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Sample records for cell repair therapy

  1. Myocardium repair with stem cell therapy

    International Nuclear Information System (INIS)

    With the aim of assessing the efficacy of bone marrow-derived stem cells transplantation in patients with myocardial infarction and severe chronic heart failure through nuclear cardiology techniques, 15 revascularized patients were studied: nine (Group I) received autologous bone marrow-derived stem cells. The other six were controls (Group II). All underwent a clinical evaluation, radionuclide ventriculography, and gated-SPECT myocardial perfusion scintigraphy (MIBI-technetium99m, two-day protocol: dipyridamole - rest), before and three months after the procedure. At three months there was a clinical improvement in 89% of patients from Group I. The left ventricular ejection fraction increased: from 32±9% to 44±13% (p=0.03; Group I) and from 38±2% to 48±14% (p NS; Group II). The peak filling rate improved from 120±11 to 196±45 EDV/sec (p=0.03; Group I). The dipyridamole summed score diminished significantly only in Group I (from 35±5 to 23±14; p=0.02). The perfusion improvement was related to the implantation site in 60% of cases. We conclude that the bone marrow-derived stem cells transplantation is effective in patients with severe chronic heart failure of ischemic origin (au)

  2. [Current cell therapy strategies for repairing the central nervous system].

    Science.gov (United States)

    Féron, F

    2007-09-01

    One of the chief contemporary goals of neurologists and neuroscientists is to find a way to overcome the debilitating effects of brain diseases, especially neurodegenerative diseases. Since very few molecules have been found to be efficient in curing the patients and even halting the progression of the symptoms, cell therapy is now seen as an attractive alternative. Two therapeutic strategies are currently under investigation: i) the "substitution" strategy, based on grafts of cells capable of differentiating in the appropriate cells and restoring lost functions and ii) the "neuroprotective" or "conservative" strategy aiming to increase the resistance of spared cells to the toxicity of their environment and to reinforce the body's own mechanisms of healing. Twenty years ago, foetal neuroblasts were the first cells to be transplanted in the brains of patients with Parkinson's or Huntington disease. A phase II clinical trial is presently conducted in France for the latter disorder. However, the numerous ethical and technical issues raised by the use of embryonic and foetal cells have directed the focus of clinicians and researchers towards substitute cell types. In this review, we summarise the main findings of the most recent basic studies and clinical trials based on: i) the grafting of surrogate adult cells such as bone marrow mesenchymal stem cells and olfactory ensheathing cells; ii) the potential therapeutic applications of neuropoiesis - the persistent neurogenesis in the brain - as a source for tissue engraftment and as self-repair by a person's own indigenous population of pluripotent cells and iii) immune-based therapy (autologous activated macrophages and T cell vaccination) as well as administration of immunomodulatory molecules. Unexpectedly, it has been found that undifferentiated adult stem cells can display immune-like functions when they home in on an inflamed brain area while immune cells and immunosuppressors can improve functional and

  3. Stem cell-based therapy in neural repair.

    Science.gov (United States)

    Hsu, Yi-Chao; Chen, Su-Liang; Wang, Dan-Yen; Chiu, Ing-Ming

    2013-01-01

    Cell-based therapy could aid in alleviating symptoms or even reversing the progression of neurodegenerative diseases and nerve injuries. Fibroblast growth factor 1 (FGF1) has been shown to maintain the survival of neurons and induce neurite outgrowth. Accumulating evidence suggests that combination of FGF1 and cell-based therapy is promising for future therapeutic application. Neural stem cells (NSCs), with the characteristics of self-renewal and multipotency, can be isolated from embryonic stem cells, embryonic ectoderm, and developing or adult brain tissues. For NSC clinical application, several critical problems remain to be resolved: (1) the source of NSCs should be personalized; (2) the isolation methods and protocols of human NSCs should be standardized; (3) the clinical efficacy of NSC transplants must be evaluated in more adequate animal models; and (4) the mechanism of intrinsic brain repair needs to be better characterized. In addition, the ideal imaging technique for tracking NSCs would be safe and yield high temporal and spatial resolution, good sensitivity and specificity. Here, we discuss recent progress and future development of cell-based therapy, such as NSCs, induced pluripotent stem cells, and induced neurons, in neurodegenerative diseases and peripheral nerve injuries. PMID:23806879

  4. Cell therapy for intervertebral disc repair: advancing cell therapy from bench to clinics

    Directory of Open Access Journals (Sweden)

    LM Benneker

    2014-05-01

    Full Text Available Intervertebral disc (IVD degeneration is a major cause of pain and disability; yet therapeutic options are limited and treatment often remains unsatisfactory. In recent years, research activities have intensified in tissue engineering and regenerative medicine, and pre-clinical studies have demonstrated encouraging results. Nonetheless, the translation of new biological therapies into clinical practice faces substantial barriers. During the symposium "Where Science meets Clinics", sponsored by the AO Foundation and held in Davos, Switzerland, from September 5-7, 2013, hurdles for translation were outlined, and ways to overcome them were discussed. With respect to cell therapy for IVD repair, it is obvious that regenerative treatment is indicated at early stages of disc degeneration, before structural changes have occurred. It is envisaged that in the near future, screening techniques and non-invasive imaging methods will be available to detect early degenerative changes. The promises of cell therapy include a sustained effect on matrix synthesis, inflammation control, and prevention of angio- and neuro-genesis. Discogenic pain, originating from "black discs" or annular injury, prevention of adjacent segment disease, and prevention of post-discectomy syndrome were identified as prospective indications for cell therapy. Before such therapy can safely and effectively be introduced into clinics, the identification of the patient population and proper standardisation of diagnostic parameters and outcome measurements are indispensable. Furthermore, open questions regarding the optimal cell type and delivery method need to be resolved in order to overcome the safety concerns implied with certain procedures. Finally, appropriate large animal models and well-designed clinical studies will be required, particularly addressing safety aspects.

  5. Repair of Ischemic Injury by Pluripotent Stem Cell Based Cell Therapy without Teratoma through Selective Photosensitivity

    Directory of Open Access Journals (Sweden)

    Seung-Ju Cho

    2015-12-01

    Full Text Available Stem-toxic small molecules have been developed to induce selective cell death of pluripotent stem cells (PSCs to lower the risk of teratoma formation. However, despite their high efficacies, chemical-based approaches may carry unexpected toxicities on specific differentiated cell types. Herein, we took advantage of KillerRed (KR as a suicide gene, to selectively induce phototoxicity using visible light via the production of reactive oxygen species. PSCs in an undifferentiated state that exclusively expressed KR (KR-PSCs were eliminated by a single exposure to visible light. This highly selective cell death in KR-PSCs was exploited to successfully inhibit teratoma formation. In particular, endothelial cells from KR-mPSCs remained fully functional in vitro and sufficient to repair ischemic injury in vivo regardless of light exposure, suggesting that a genetic approach in which KR is expressed in a tightly controlled manner would be a viable strategy to inhibit teratoma formation for future safe PSC-based therapies.

  6. Cell and gene therapy for arrhythmias: Repair of cardiac conduction damage

    Institute of Scientific and Technical Information of China (English)

    Yong-Fu Xiao

    2011-01-01

    Action potentials generated in the sinoatrial node(SAN)dominate the rhythm and rate of a healthy human heart.Subsequently,these action potentials propagate to the whole heart via its conduction system .Abnormalities of impulse generation and/or propagation in a heart can cause arrhythmias.For example,SAN dysfunction or conduction block of the atrioventricular node can lead to serious bradycardia which is currently treated with an implanted electronic pacemaker.On the other hand conduction damage may cause reentrant tachyarrhythmias which are primarily treated pharmacologically or by medical device-based therapies,including defibrillation and tissue ablation.However,drug therapies sometimes may not be effective or are associated with serious side effects.Device-based therapies for cardiac arrhythmias,even with well developed technology,still face inadequacies,limitations,hardware complications,and other challenges.Therefore,scientists are actively seeking other alternatives for antiarrhythmic therapy.In particular,cells and genes used for repairing cardiac conduction damage/defect have been investigated in various studies both in vitro and in vivo.Despite the complexities of the excitation and conduction systems of the heart,cell and gene-based strategies provide novel alternatives for treatment or cure of cardiac anhythmias.This review summarizes some highlights of recent research progress in this field.

  7. Concise review: Insights from normal bone remodeling and stem cell-based therapies for bone repair.

    Science.gov (United States)

    Khosla, Sundeep; Westendorf, Jennifer J; Mödder, Ulrike I

    2010-12-01

    There is growing interest in the use of mesenchymal stem cells for bone repair. As a major reason for normal bone remodeling is the removal of fatigue microcracks, advances in our understanding of this process may inform approaches to enhance fracture healing. Increasing evidence now indicates that physiological bone remodeling occurs in close proximity to blood vessels and that these vessels carry perivascular stem cells that differentiate into osteoblasts. Similarly, fracture healing is critically dependent on the ingrowth of blood vessels not only for a nutrient supply but also for the influx of osteoblasts. A number of animal and human studies have now shown the potential benefit of bone marrow-derived mesenchymal stem cells in enhancing bone repair. However, as in other tissues, the question of whether these cells improve fracture healing directly by differentiating into osteoblasts or indirectly by secreting paracrine factors that recruit blood vessels and the accompanying perivascular stem cells remains a major unresolved issue. Moreover, CD34+ cells, which are enriched for endothelial/hematopoietic cells, have also shown efficacy in various bone repair models, at least in part due to the induction of angiogenesis and recruitment of host progenitor cells. Thus, mesenchymal and nonmesenchymal stem/progenitor cells are attractive options for bone repair. It is possible that they contribute directly to bone repair, but it is also likely that they express paracrine factors in the appropriate amounts and combinations that promote and sustain the healing process. PMID:20960512

  8. Tissue engineering and cell based therapies, from the bench to the clinic: The potential to replace, repair and regenerate

    Directory of Open Access Journals (Sweden)

    Fodor William L

    2003-11-01

    Full Text Available Abstract The field of Regenerative Biology as it applies to Regenerative Medicine is an increasingly expanding area of research with hopes of providing therapeutic treatments for diseases and/or injuries that conventional medicines and even new biologic drug therapies cannot effectively treat. Extensive research in the area of Regenerative Medicine is focused on the development of cells, tissues and organs for the purpose of restoring function through transplantation. The general belief is that replacement, repair and restoration of function is best accomplished by cells, tissues or organs that can perform the appropriate physiologic/metabolic duties better than any mechanical device, recombinant protein therapeutic or chemical compound. Several strategies are currently being investigated and include, cell therapies derived from autologous primary cell isolates, cell therapies derived from established cell lines, cell therapies derived from a variety of stem cells, including bone marrow/mesenchymal stem cells, cord blood stem cells, embryonic stem cells, as well as cells tissues and organs from genetically modified animals. This mini-review is not meant to be exhaustive, but aims to highlight clinical applications for the four areas of research listed above and will address a few key advances and a few of the hurdles yet to be overcome as the technology and science improve the likelihood that Regenerative Medicine will become clinically routine.

  9. Concise Review: Insights from Normal Bone Remodeling and Stem Cell-Based Therapies for Bone Repair

    OpenAIRE

    Khosla, Sundeep; Westendorf, Jennifer J.; Mödder, Ulrike I.

    2010-01-01

    There is growing interest in the use of mesenchymal stem cells for bone repair. Since a major reason for normal bone remodeling is the removal of fatigue microcracks, advances in our understanding of this process may inform approaches to enhancing fracture healing. Increasing evidence now indicates that physiological bone remodeling occurs in close proximity to blood vessels and that these vessels carry perivascular stem cells that differentiate into osteoblasts. Similarly, fracture healing i...

  10. Reprogramming Cells for Brain Repair

    OpenAIRE

    McKinnon, Randall D.; Alyx T. Guarino

    2013-01-01

    At present there are no clinical therapies that can repair traumatic brain injury, spinal cord injury or degenerative brain disease. While redundancy and rewiring of surviving circuits can recover some lost function, the brain and spinal column lack sufficient endogenous stem cells to replace lost neurons or their supporting glia. In contrast, pre-clinical studies have demonstrated that exogenous transplants can have remarkable efficacy for brain repair in animal models. Mesenchymal stromal c...

  11. Dual Differentiation-Exogenous Mesenchymal Stem Cell Therapy for Traumatic Spinal Cord Injury Repair in a Murine Hemisection Model

    Directory of Open Access Journals (Sweden)

    Hai Liu

    2013-01-01

    Full Text Available Mesenchymal stem cell (MSC transplantation has shown tremendous promise as a therapy for repair of various tissues of the musculoskeletal, vascular, and central nervous systems. Based on this success, recent research in this field has focused on complex tissue damage, such as that which occurs from traumatic spinal cord injury (TSCI. As the critical event for successful exogenous, MSC therapy is their migration to the injury site, which allows for their anti-inflammatory and morphogenic effects on fracture healing, neuronal regeneration, and functional recover. Thus, there is a need for a cost-effective in vivo model that can faithfully recapitulate the salient features of the injury, therapy, and recovery. To address this, we review the recent advances in exogenous MSC therapy for TSCI and traumatic vertebral fracture repair and the existing challenges regarding their translational applications. We also describe a novel murine model designed to take advantage of multidisciplinary collaborations between musculoskeletal and neuroscience researchers, which is needed to establish an efficacious MSC therapy for TSCI.

  12. Reprogramming Cells for Brain Repair

    Directory of Open Access Journals (Sweden)

    Randall D. McKinnon

    2013-08-01

    Full Text Available At present there are no clinical therapies that can repair traumatic brain injury, spinal cord injury or degenerative brain disease. While redundancy and rewiring of surviving circuits can recover some lost function, the brain and spinal column lack sufficient endogenous stem cells to replace lost neurons or their supporting glia. In contrast, pre-clinical studies have demonstrated that exogenous transplants can have remarkable efficacy for brain repair in animal models. Mesenchymal stromal cells (MSCs can provide paracrine factors that repair damage caused by ischemic injury, and oligodendrocyte progenitor cell (OPC grafts give dramatic functional recovery from spinal cord injury. These studies have progressed to clinical trials, including human embryonic stem cell (hESC-derived OPCs for spinal cord repair. However, ESC-derived allografts are less than optimal, and we need to identify a more appropriate donor graft population. The cell reprogramming field has developed the ability to trans-differentiate somatic cells into distinct cell types, a technology that has the potential to generate autologous neurons and glia which address the histocompatibility concerns of allografts and the tumorigenicity concerns of ESC-derived grafts. Further clarifying how cell reprogramming works may lead to more efficient direct reprogram approaches, and possibly in vivo reprogramming, in order to promote brain and spinal cord repair.

  13. DNA damage and repair kinetics after microbeam radiation therapy emulation in living cells using monoenergetic synchrotron X-ray microbeams

    International Nuclear Information System (INIS)

    The molecular response of mammalian cells to a monoenergetic synchrotron X-ray microbeam which emulated microbeam radiation configurations has been investigated. Very few γH2AX foci were found outside the irradiated zone within 1 h of irradiation, even within a single nucleus. Furthermore, 12 h after radiation there was a large decrease in foci number but many cells still contained γH2AX foci, of which many were outside the directly irradiated regions. A novel synchrotron-based approach, known as microbeam radiation therapy (MRT), currently shows considerable promise in increased tumour control and reduced normal tissue damage compared with conventional radiotherapy. Different microbeam widths and separations were investigated using a controlled cell culture system and monoenergetic (5.35 keV) synchrotron X-rays in order to gain further insight into the underlying cellular response to MRT. DNA damage and repair was measured using fluorescent antibodies against phosphorylated histone H2AX, which also allowed us to verify the exact location of the microbeam path. Beam dimensions that reproduced promising MRT strategies were used to identify useful methods to study the underpinnings of MRT. These studies include the investigation of different spatial configurations on bystander effects. γH2AX foci number were robustly induced in directly hit cells and considerable DNA double-strand break repair occurred by 12 h post-10 Gy irradiation; however, many cells had some γH2AX foci at the 12 h time point. γH2AX foci at later time points did not directly correspond with the targeted regions suggesting cell movement or bystander effects as a potential mechanism for MRT effectiveness. Partial irradiation of single nuclei was also investigated and in most cases γH2AX foci were not observed outside the field of irradiation within 1 h after irradiation indicating very little chromatin movement in this time frame. These studies contribute to the understanding of the

  14. DNA repair in cancer: emerging targets for personalized therapy

    International Nuclear Information System (INIS)

    Genomic deoxyribonucleic acid (DNA) is under constant threat from endogenous and exogenous DNA damaging agents. Mammalian cells have evolved highly conserved DNA repair machinery to process DNA damage and maintain genomic integrity. Impaired DNA repair is a major driver for carcinogenesis and could promote aggressive cancer biology. Interestingly, in established tumors, DNA repair activity is required to counteract oxidative DNA damage that is prevalent in the tumor microenvironment. Emerging clinical data provide compelling evidence that overexpression of DNA repair factors may have prognostic and predictive significance in patients. More recently, DNA repair inhibition has emerged as a promising target for anticancer therapy. Synthetic lethality exploits intergene relationships where the loss of function of either of two related genes is nonlethal, but loss of both causes cell death. Exploiting this approach by targeting DNA repair has emerged as a promising strategy for personalized cancer therapy. In the current review, we focus on recent advances with a particular focus on synthetic lethality targeting in cancer

  15. Mesenchymal Stem Cell Therapy for Protection and Repair of Injured Vital Organs

    NARCIS (Netherlands)

    van Poll, D.; Parekkadan, B.; Rinkes, I. H. M. Borel; Tilles, A. W.; Yarmush, M. L.

    2008-01-01

    Recently there has been a paradigm shift in what is considered to be the therapeutic promise of mesenchymal stem cells (MSCs) in diseases of vital organs. Originally, research focused on MSCs as a source of regenerative cells by differentiation of transplanted cells into lost cell types. It is now c

  16. Genotoxic therapy stimulates error-prone DNA repair in dormant hepatocellular cancer stem cells

    OpenAIRE

    Nishikawa, Shimpei; Ishii, Hideshi; HARAGUCHI, NAOTSUGU; Kano, Yoshihiro; FUKUSUMI, TAKAHITO; OHTA, KATSUYA; OZAKI, MIYUKI; Sakai, Daisuke; SATOH, TAROH; Nagano, Hiroaki; Doki, Yuichiro; Mori, Masaki

    2012-01-01

    Previous studies have described distinct dormant and proliferating populations of cancer stem cells in hepatocellular carcinoma. The CD13 protein is involved in the scavenging of reactive oxygen species through the glutathione reductase pathway and is associated with resistance to chemotherapy. Whereas CD13− proliferating cancer stem cells are sensitive to chemotherapy, CD13+ dormant cancer stem cells are associated with the development of resistance to chemotherapy. CD13+ cells in hypoxic ar...

  17. Damage-repair processes in thermal neutron capture therapy

    International Nuclear Information System (INIS)

    Radiobiological specificity of thermal neutron capture therapy was examined using cultured cell lines of B16 mouse melanoma cells and of V79 Chinese hamster cells, with particular reference to the recovery from sublethal radiation damage (SLD) and potentially lethal radiation damage (PLD). A boron compound used was 10B1-para-boronophenylalanine (10B1-BPA). Cell survival curves of B16 melanoma cells irradiated with thermal neutrons alone had no shoulders. Cells treated with 10B1-BPA followed by thermal neutron irradiation showed remarkably enhanced killing in proportion to the concentration of 10B1-BPA. Neither B16 cells nor V79 cells possessed the ability to repair SLD. The B16 cells possessed little ability to repair 10B1-BPA plus thermal neutrons-induced PLD. Some cells possessed the ability to sequentially repair PLD when caffeine was added to the cell medium during irradiation. B16 cells efficiently repaired x ray-induced slow type PLD, but could not repair thermal neutron-induced PLD or 10B1-BPA plus thermal neutron-induced PLD. V79 cells possessed a greater ability to repair both x ray-induced PLD and thermal neutron-induced PLD than B16 melanoma cells. (Namekawa, K.)

  18. Cell Therapy for Multiple Sclerosis

    OpenAIRE

    Ben-Hur, Tamir

    2011-01-01

    The spontaneous recovery observed in the early stages of multiple sclerosis (MS) is substituted with a later progressive course and failure of endogenous processes of repair and remyelination. Although this is the basic rationale for cell therapy, it is not clear yet to what degree the MS brain is amenable for repair and whether cell therapy has an advantage in comparison to other strategies to enhance endogenous remyelination. Central to the promise of stem cell therapy is the therapeutic pl...

  19. A combined cell therapy and in-situ tissue-engineering approach for myocardial repair.

    Science.gov (United States)

    Habib, Manhal; Shapira-Schweitzer, Keren; Caspi, Oren; Gepstein, Amira; Arbel, Gil; Aronson, Doron; Seliktar, Dror; Gepstein, Lior

    2011-10-01

    Myocardial cell-replacement strategies are hampered by limited sources for human cardiomyocytes and by significant cell loss following transplantation. We tested the hypothesis that a combined delivery of cardiomyocytes with an in-situ polymerizable hydrogel into a post-MI rat heart will result in better functional outcomes than each intervention alone. A photopolymerizable, biodegradable, PEGylated-fibrinogen (PF) hydrogel matrix was used as the carrier for the cardiomyocytes [neonatal rat ventricular cardiomyocytes (NRVCMs) or human embryonic stem cell-derived cardiomyocytes (hESC-CMs)]. Infarcted rat hearts (LAD ligation) were randomized to injection of saline, NRVCMs, biopolymer, or combined biopolymer-cell delivery. Echocardiography revealed typical post-infarction remodeling after 30 days in the saline-injected control group [deterioration of fractional shortening (FS) by 31.0 ± 3.6%]. Injection of NRVCMs or PF alone significantly (p hydrogel can act as a cardiomyocyte cell-carrier and add to the beneficial effects of the grafted cells in preventing unfavorable post-infarction cardiac remodeling. PMID:21783246

  20. Current perspectives in stem cell therapy for spinal cord repair in humans: a review of work from the past 10 years

    Directory of Open Access Journals (Sweden)

    Eric Domingos Mariano

    2014-06-01

    Full Text Available Spinal cord injury (SCI and amyotrophic laterals sclerosis (ALS are devastating neurological conditions that affect individuals worldwide, significantly reducing quality of life, both for patients and their relatives. Objective : The present review aims to summarize the multiple restorative approaches being developed for spinal cord repair, the use of different stem cell types and the current knowledge regarding stem cell therapy. Method : Review of the literature from the past 10 years of human studies using stem cell transplantation as the main therapy, with or without adjuvant therapies. Conclusion : The current review offers an overview of the state of the art regarding spinal cord restoration, and serves as a starting point for future studies.

  1. Stem cell therapy to protect and repair the developing brain: a review of mechanisms of action of cord blood and amnion epithelial derived cells

    Directory of Open Access Journals (Sweden)

    Margie eCastillo-Melendez

    2013-10-01

    Full Text Available In the research, clinical and wider community there is great interest in the use of stem cells to reduce the progression, or indeed repair brain injury. Perinatal brain injury may result from acute or chronic insults sustained during fetal development, during the process of birth, or in the newborn period. The most readily identifiable outcome of perinatal brain injury is cerebral palsy, however this is just one consequence in a spectrum of mild to severe neurological deficits. As we review, there are now clinical trials taking place worldwide targeting cerebral palsy with stem cell therapies. It will likely be many years before strong evidence-based results emerge from these trials. With such trials underway, it is both appropriate and timely to address the physiological basis for the efficacy of stem-like cells in preventing damage to, or regenerating, the newborn brain. Appropriate experimental animal models are best placed to deliver this information. Cell availability, the potential for immunological rejection, ethical and logistical considerations, together with the propensity for native cells to form terratomas, make it unlikely that embryonic or fetal stem cells will be practical. Fortunately, these issues do not pertain to the use of human amnion epithelial cells (hAECs, or umbilical cord blood (UCB stem cells that are readily and economically obtained from the placenta and umbilical cord discarded at birth. These cells have the potential for transplantation to the newborn where brain injury is diagnosed or even suspected. We will explore the novel characteristics of hAECs and undifferentiated UCB cells, as well as UCB-derived endothelial progenitor cells and mesenchymal stem cells, and how immunomodulation and anti-inflammatory properties are principal mechanisms of action that are common to these cells, and which in turn may ameliorate the cerebral hypoxia and inflammation that are final pathways in the pathogenesis of perinatal brain

  2. Stem cells and repair of lung injuries

    Directory of Open Access Journals (Sweden)

    Randell Scott H

    2004-07-01

    Full Text Available Abstract Fueled by the promise of regenerative medicine, currently there is unprecedented interest in stem cells. Furthermore, there have been revolutionary, but somewhat controversial, advances in our understanding of stem cell biology. Stem cells likely play key roles in the repair of diverse lung injuries. However, due to very low rates of cellular proliferation in vivo in the normal steady state, cellular and architectural complexity of the respiratory tract, and the lack of an intensive research effort, lung stem cells remain poorly understood compared to those in other major organ systems. In the present review, we concisely explore the conceptual framework of stem cell biology and recent advances pertinent to the lungs. We illustrate lung diseases in which manipulation of stem cells may be physiologically significant and highlight the challenges facing stem cell-related therapy in the lung.

  3. Stem cells for cardiac repair: an introduction

    Institute of Scientific and Technical Information of China (English)

    Bastiaan C du Pr(e); Pieter A Doevendans; Linda W van Laake

    2013-01-01

    Cardiovascular disease is a major cause of morbidity and mortality throughout the world. Most cardiovascular diseases, such as ischemic heart disease and cardiomyopathy, are associated with loss of functional cardiomyocytes. Unfortunately, the heart has a limited regenerative capacity and is not able to replace these cardiomyocytes once lost. In recent years, stem cells have been put forward as a potential source for cardiac regeneration. Pre-clinical studies that use stem cell-derived cardiac cells show promising results. The mechanisms, though, are not well understood, results have been variable, sometimes transient in the long term, and often without a mechanistic explanation. There are still several major hurdles to be taken. Stem cell-derived cardiac cells should resemble original cardiac cell types and be able to integrate in the damaged heart. Integration requires administration of stem cell-derived cardiac cells at the right time using the right mode of delivery. Once delivered, transplanted cells need vascularization, electrophysiological coupling with the injured heart, and prevention of immunological rejection. Finally, stem cell therapy needs to be safe, reproducible, and affordable. In this review, we will give an introduction to the principles of stem cell based cardiac repair.

  4. Stem cell-based bone repair

    OpenAIRE

    Fei, Yurong; Xu, Ren-He; Hurley, Marja M.

    2012-01-01

    To accelerate bone repair, one strategy is to deliver the cells that make bone. The current review focuses on stem cell-based bone repair. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can self-renew unlimitedly and differentiate into the bone forming cells – osteoblasts. Scientists have been actively investigating culture conditions to stably and efficiently induce differentiation of these stem cells into osteoblasts. However, ESCs have the issues of ethnics, immune ...

  5. (64)Cu-ATSM therapy targets regions with activated DNA repair and enrichment of CD133(+) cells in an HT-29 tumor model: Sensitization with a nucleic acid antimetabolite.

    Science.gov (United States)

    Yoshii, Yukie; Furukawa, Takako; Matsumoto, Hiroki; Yoshimoto, Mitsuyoshi; Kiyono, Yasushi; Zhang, Ming-Rong; Fujibayashi, Yasuhisa; Saga, Tsuneo

    2016-06-28

    (64)Cu-diacetyl-bis (N(4)-methylthiosemicarbazone) ((64)Cu-ATSM) is a potential theranostic agent targeting the over-reduced state under hypoxia within tumors. Recent clinical Cu-ATSM positron emission tomography studies have revealed a correlation between uptake and poor prognosis; however, the reason is unclear. Here, using a human colon carcinoma HT-29 model, we demonstrated that the intratumoral (64)Cu-ATSM high-uptake regions exhibited malignant characteristics, such as upregulated DNA repair and elevated %CD133(+) cancer stem-like cells. Based on this evidence, we developed a strategy to enhance the efficacy of (64)Cu-ATSM internal radiotherapy (IRT) by inhibiting DNA repair with a nucleic acid (NA) antimetabolite. The results of the analyses showed upregulation of pathways related to DNA repair along with NA incorporation (bromodeoxyuridine uptake) and elevation of %CD133(+) cells in (64)Cu-ATSM high-uptake regions. In an in vivo(64)Cu-ATSM treatment study, co-administration of an NA antimetabolite and (64)Cu-ATSM synergistically inhibited tumor growth, with little toxicity, and effectively reduced %CD133(+) cells. (64)Cu-ATSM therapy targeted malignant tumor regions with activated DNA repair and high concentrations of CD133(+) cells in the HT-29 model. NA antimetabolite co-administration can be an effective approach to enhance the therapeutic effect of (64)Cu-ATSM IRT. PMID:26996296

  6. Adult stem cells and tissue repair.

    Science.gov (United States)

    Körbling, M; Estrov, Z; Champlin, R

    2003-08-01

    Recently, adult stem cells originating from bone marrow or peripheral blood have been suggested to contribute to repair and genesis of cells specific for liver, cardiac and skeletal muscle, gut, and brain tissue. The mechanism involved has been termed transdifferentiation, although other explanations including cell fusion have been postulated. Using adult stem cells to generate or repair solid organ tissue obviates the immunologic, ethical, and teratogenic issues that accompany embryonic stem cells. PMID:12931235

  7. New Therapy of Skin Repair Combining Adipose-Derived Mesenchymal Stem Cells with Sodium Carboxymethylcellulose Scaffold in a Pre-Clinical Rat Model

    OpenAIRE

    Cristiano Rodrigues; de Assis, Adriano M.; Moura, Dinara J.; Graziele Halmenschlager; Jenifer Saffi; Léder Leal Xavier; Marilda da Cruz Fernandes; Márcia Rosângela Wink

    2014-01-01

    Lesions with great loss of skin and extensive burns are usually treated with heterologous skin grafts, which may lead rejection. Cell therapy with mesenchymal stem cells is arising as a new proposal to accelerate the healing process. We tested a new therapy consisting of sodium carboxymethylcellulose (CMC) as a biomaterial, in combination with adipose-derived stem cells (ADSCs), to treat skin lesions in an in vivo rat model. This biomaterial did not affect membrane viability and induced a sma...

  8. Difference in Membrane Repair Capacity Between Cancer Cell Lines and a Normal Cell Line.

    Science.gov (United States)

    Frandsen, Stine Krog; McNeil, Anna K; Novak, Ivana; McNeil, Paul L; Gehl, Julie

    2016-08-01

    Electroporation-based treatments and other therapies that permeabilize the plasma membrane have been shown to be more devastating to malignant cells than to normal cells. In this study, we asked if a difference in repair capacity could explain this observed difference in sensitivity. Membrane repair was investigated by disrupting the plasma membrane using laser followed by monitoring fluorescent dye entry over time in seven cancer cell lines, an immortalized cell line, and a normal primary cell line. The kinetics of repair in living cells can be directly recorded using this technique, providing a sensitive index of repair capacity. The normal primary cell line of all tested cell lines exhibited the slowest rate of dye entry after laser disruption and lowest level of dye uptake. Significantly, more rapid dye uptake and a higher total level of dye uptake occurred in six of the seven tested cancer cell lines (p electroporation. Viability in the primary normal cell line (98 % viable cells) was higher than in the three tested cancer cell lines (81-88 % viable cells). These data suggest more effective membrane repair in normal, primary cells and supplement previous explanations why electroporation-based therapies and other therapies permeabilizing the plasma membrane are more effective on malignant cells compared to normal cells in cancer treatment. PMID:27312328

  9. Therapeutic potential of stem cells in auditory hair cell repair

    Directory of Open Access Journals (Sweden)

    Ryuji Hata

    2009-01-01

    Full Text Available The prevalence of acquired hearing loss is very high. About 10% of the total population and more than one third of the population over 65 years suffer from debilitating hearing loss. The most common type of hearing loss in adults is idiopathic sudden sensorineural hearing loss (ISSHL. In the majority of cases, ISSHL is permanent and typically associated with loss of sensory hair cells in the organ of Corti. Following the loss of sensory hair cells, the auditory neurons undergo secondary degeneration. Sensory hair cells and auditory neurons do not regenerate throughout life, and loss of these cells is irreversible and cumulative. However, recent advances in stem cell biology have gained hope that stem cell therapy comes closer to regenerating sensory hair cells in humans. A major advance in the prospects for the use of stem cells to restore normal hearing comes with the recent discovery that hair cells can be generated ex vivo from embryonic stem (ES cells, adult inner ear stem cells and neural stem cells. Furthermore, there is increasing evidence that stem cells can promote damaged cell repair in part by secreting diffusible molecules such as growth factors. These results suggest that stem-cell-based treatment regimens can be applicable to the damaged inner ear as future clinical applications.Previously we have established an animal model of cochlear ischemia in gerbils and showed progressive hair cell loss up to 4 days after ischemia. Auditory brain stem response (ABR recordings have demonstrated that this gerbil model displays severe deafness just after cochlear ischemia and gradually recovers thereafter. These pathological findings and clinical manifestations are reminiscent of ISSHL in humans. In this study, we have shown the effectiveness of stem cell therapy by using this animal model of ISSHL.

  10. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis

  11. Mechanical injury and repair of cells

    Science.gov (United States)

    Miyake, Katsuya; McNeil, Paul L.

    2003-01-01

    OBJECTIVE: To concisely review the field of cell plasma membrane disruption (torn cell surface) and repair. MAIN POINTS: Plasma membrane disruption is a common form of cell injury under physiologic conditions, after trauma, in certain muscular dystrophies, and during certain forms of clinical intervention. Rapid repair of a disruption is essential to cell survival and involves a complex and active cell response that includes membrane fusion and cytoskeletal activation. Tissues, such as cardiac and skeletal muscle, adapt to a disruption injury by hypertrophying. Cells adapt by increasing the efficiency of their resealing response. CONCLUSION: Plasma membrane disruption is an important cellular event in both health and disease. The disruption repair mechanism is now well understood at the cellular level, but much remains to be learned at the molecular level. Cell and tissue level adaptational responses to the disruption either prevent its further occurrence or facilitate future repairs. Therapeutically useful drugs might result if, using this accumulating knowledge, chemical agents can be developed that can enhance repair or adaptive responses.

  12. DNA repair in human bronchial epithelial cells

    International Nuclear Information System (INIS)

    The purpose of this investigation was to compare the response of human cell types (bronchial epithelial cells and fibroblasts and skin fibroblasts) to various DNA damaging agents. Repair of DNA single strand breaks (SSB) induced by 5 krads of X-ray was similar for all cell types; approximately 90% of the DNA SSB were rejoined within one hour. During excision repair of DNA damage from u.v.-radiation, the frequencies of DNA SSB as estimated by the alkaline elution technique, were similar in all cell types. Repair replication as measured by BND cellulose chromatography was also similar in epithelial and fibroblastic cells after u.v.-irradiation. Similar levels of SSB were also observed in epithelial and fibroblastic cells after exposure to chemical carcinogens: 7,12-dimethylbenz[a]anthracene; benzo[a]pyrene diol epoxide (BPDE); or N-methyl-N-nitro-N-nitrosoguanidine. Significant repair replication of BPDE-induced DNA damage was detected in both bronchial epithelial and fibroblastic cells, although the level in fibroblasts was approximately 40% of that in epithelial cells. The pulmonary carcinogen asbestos did not damage DNA. DNA-protein crosslinks induced by formaldehyde were rapidly removed in bronchial cells. Further, epithelial and fibroblastic cells, which were incubated with formaldehyde and the polymerase inhibitor combination of cytosine arabinoside and hydroxyurea, accumulated DNA SSB at approximately equal frequencies. These results should provide a useful background for further investigations of the response of human bronchial cells to various DNA damaging agents

  13. Mechanisms of DNA Repair in Mammalian Cells

    International Nuclear Information System (INIS)

    The authors examined DNA synthesis in cultured mammalian cells after irradiation with X-rays or ultraviolet light, using equilibrium density gradient and autoradiographic techniques. Unscheduled DNA synthesis (the synthesis of DNA by cells not in S phase of the cell cycle) occurs at doses of u.v. where survival is greater than 90% and at doses of X-rays where survival is of the order of 50%. At higher doses it was established that repair replication (insertion of precursors into parental strands of DNA ) occurs in these cells, and it is presumed that these two phenomena (unscheduled DNA synthesis and repair replication) are manifestations of the same repair process. During the time that these phenomena occur, very little degradation of DNA takes place, as measured by appearance of prelabelled components of DNA in the medium or in the acid soluble portion of the cell. This is in direct contrast to the situation in bacteria, in which extensive degradation of DNA occurs after irradiation, presumably as a result of enzymatic processes that remove many undamaged bases in addition to the ones injured by the irradiation. A small amount of radioactivity does appear in the acid soluble portion and in the media from prelabelled cells from both irradiated and control mammalian cell cultures. The amount in the medium from irradiated cultures is slightly, but significantly, greater than that from controls; thus there does appear to be a very low level of degradation of DNA in irradiated mammalian cells. These data indicate that the repair of DNA in mammalian cells does not involve the same steps as those that occur in bacteria. The results suggest instead that mammalian cells have a much more specific system for repair, which involves excision of only the damaged portion of the DNA. Possible mechanisms of repair of mammalian DNA are considered. (author)

  14. New therapy of skin repair combining adipose-derived mesenchymal stem cells with sodium carboxymethylcellulose scaffold in a pre-clinical rat model.

    Directory of Open Access Journals (Sweden)

    Cristiano Rodrigues

    Full Text Available Lesions with great loss of skin and extensive burns are usually treated with heterologous skin grafts, which may lead rejection. Cell therapy with mesenchymal stem cells is arising as a new proposal to accelerate the healing process. We tested a new therapy consisting of sodium carboxymethylcellulose (CMC as a biomaterial, in combination with adipose-derived stem cells (ADSCs, to treat skin lesions in an in vivo rat model. This biomaterial did not affect membrane viability and induced a small and transient genotoxicity, only at the highest concentration tested (40 mg/mL. In a rat wound model, CMC at 10 mg/mL associated with ADSCs increased the rate of cell proliferation of the granulation tissue and epithelium thickness when compared to untreated lesions (Sham, but did not increase collagen fibers nor alter the overall speed of wound closure. Taken together, the results show that the CMC is capable to allow the growth of ADSCs and is safe for this biological application up to the concentration of 20 mg/mL. These findings suggest that CMC is a promising biomaterial to be used in cell therapy.

  15. Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) combination therapy through impairing intracellular ATP production and DNA repair in breast cancer stem cells.

    Science.gov (United States)

    Soo, Jaslyn Sian-Siu; Ng, Char-Hong; Tan, Si Hoey; Malik, Rozita Abdul; Teh, Yew-Ching; Tan, Boon-Shing; Ho, Gwo-Fuang; See, Mee-Hoong; Taib, Nur Aishah Mohd; Yip, Cheng-Har; Chung, Felicia Fei-Lei; Hii, Ling-Wei; Teo, Soo-Hwang; Leong, Chee-Onn

    2015-10-01

    Metformin, an AMPK activator, has been reported to improve pathological response to chemotherapy in diabetic breast cancer patients. To date, its mechanism of action in cancer, especially in cancer stem cells (CSCs) have not been fully elucidated. In this study, we demonstrated that metformin, but not other AMPK activators (e.g. AICAR and A-769662), synergizes 5-fluouracil, epirubicin, and cyclophosphamide (FEC) combination chemotherapy in non-stem breast cancer cells and breast cancer stem cells. We show that this occurs through an AMPK-dependent mechanism in parental breast cancer cell lines. In contrast, the synergistic effects of metformin and FEC occurred in an AMPK-independent mechanism in breast CSCs. Further analyses revealed that metformin accelerated glucose consumption and lactate production more severely in the breast CSCs but the production of intracellular ATP was severely hampered, leading to a severe energy crisis and impairs the ability of CSCs to repair FEC-induced DNA damage. Indeed, addition of extracellular ATP completely abrogated the synergistic effects of metformin on FEC sensitivity in breast CSCs. In conclusion, our results suggest that metformin synergizes FEC sensitivity through distinct mechanism in parental breast cancer cell lines and CSCs, thus providing further evidence for the clinical relevance of metformin for the treatment of cancers. PMID:26276035

  16. Mesenchymal Stem Cell-Based Therapy

    OpenAIRE

    Mundra, Vaibhav; Gerling, Ivan C.; Mahato, Ram I.

    2012-01-01

    Mesenchymal stem cells (MSCs) are multipotent adult stem cells which have self-renewal capacity and differentiation potential into several mesenchymal lineages including bones, cartilages, adipose tissues and tendons. MSCs may repair tissue injuries and prevent immune cell activation and proliferation. Immunomodulation and secretion of growth factors by MSCs have led to realizing the true potential of MSC-based cell therapy. The use of MSCs as immunomdulators has been explored in cell/organ t...

  17. Stem cells for skeletal muscle repair

    OpenAIRE

    Shadrach, Jennifer L.; Wagers, Amy J.

    2011-01-01

    Skeletal muscle is a highly specialized tissue composed of non-dividing, multi-nucleated muscle fibres that contract to generate force in a controlled and directed manner. Skeletal muscle is formed during embryogenesis from a subset of muscle precursor cells, which generate both differentiated muscle fibres and specialized muscle-forming stem cells known as satellite cells. Satellite cells remain associated with muscle fibres after birth and are responsible for muscle growth and repair throug...

  18. Repair-misrepair model of cell survival

    International Nuclear Information System (INIS)

    During the last three years a new model, the repair-misrepair model (RMR) has been proposed, to interpret radiobiological experiments with heavy ions. In using the RMR model it became apparent that some of its features are suitable for handling the effects produced by a variety of environmental agents in addition to ionizing radiation. Two separate sequences of events are assumed to take place in an irradiated cell. The first sequence begins with an initial energy transfer consisting of ionizations and excitations, culminating via fast secondary physical and chemical processes in established macromolecular lesions in essential cell structures. The second sequence contains the responses of the cell to the lesions and consists of the processes of recognition and molecular repair. In normal cells there exists one repair process or at most a few enzymatic repair processes for each essential macromolecular lesion. The enzymatic repair processes may last for hours and minutes, and can be separated in time from the initial physicochemical and later genetic phases

  19. Mutagenesis and DNA repair in mammalian cells

    International Nuclear Information System (INIS)

    Two aspects of DNA damage and repair in mammalian cells were investigated. Using a lambda phage shuttle vector, a system was developed to study mutations arising in the DNA of mammalian cells. This system was used to determine the spectrum of mutations induced in cellular DNA by ultraviolet light. Also, the repair of base pair mismatches in DNA was studied by the development of a method to detect a DNA mismatch repair activity in extracts made from cultured human cells. In order to study mutations arising in mammalian cells, stable mouse L cell lines were established with multiple copies of lambda phage vector which contains the supF gene of E. coli as a target for mutagenesis. Rescue of viable phage from high molecular weight mouse cell DNA using lambda in vitro packaging extracts was efficient and yielded a negligible background of phage with mutations in the supF gene. From mouse cells exposed to 12 J/m2 of 254 nm ultraviolet (UV) light, 78,510 phage were rescued of which eight were found to have mutant supF genes. DNA sequence analysis of the mutants suggests that the primary site of UV mutagenesis in mammalian cells is at pyrimidine-cytosine (Py-C) sequences, and that the most frequent mutation at this site is a C to T transition

  20. American Society of Gene & Cell Therapy

    Science.gov (United States)

    ... Resources Clinical Trials Information Gene Therapy and Cell Therapy Terminology Gene Therapy & Cell Therapy Breakthroughs FAQs Gene Therapy and Cell Therapy Defined Gene Therapy and Cell Therapy for Diseases Sites of ...

  1. DNA repair in murine embryonic stem cells and differentiated cells

    International Nuclear Information System (INIS)

    Embryonic stem (ES) cells are rapidly proliferating, self-renewing cells that have the capacity to differentiate into all three germ layers to form the embryo proper. Since these cells are critical for embryo formation, they must have robust prophylactic mechanisms to ensure that their genomic integrity is preserved. Indeed, several studies have suggested that ES cells are hypersensitive to DNA damaging agents and readily undergo apoptosis to eliminate damaged cells from the population. Other evidence suggests that DNA damage can cause premature differentiation in these cells. Several laboratories have also begun to investigate the role of DNA repair in the maintenance of ES cell genomic integrity. It does appear that ES cells differ in their capacity to repair damaged DNA compared to differentiated cells. This minireview focuses on repair mechanisms ES cells may use to help preserve genomic integrity and compares available data regarding these mechanisms with those utilized by differentiated cells

  2. Intraoperative Stem Cell Therapy

    OpenAIRE

    Coelho, Mónica Beato; Cabral, Joaquim M. S.; Karp, Jeffrey M.

    2012-01-01

    Stem cells hold significant promise for regeneration of tissue defects and disease-modifying therapies. Although numerous promising stem cell approaches are advancing in clinical trials, intraoperative stem cell therapies offer more immediate hope by integrating an autologous cell source with a well-established surgical intervention in a single procedure. Herein, the major developments in intraoperative stem cell approaches, from in vivo models to clinical studies, are reviewed, and the poten...

  3. Nonclinical safety strategies for stem cell therapies

    Energy Technology Data Exchange (ETDEWEB)

    Sharpe, Michaela E., E-mail: michaela_sharpe@yahoo.com [Investigative Toxicology, Drug Safety Research and Development, Pfizer Ltd, Ramsgate Road, Sandwich, CT13 9NJ (United Kingdom); Morton, Daniel [Exploratory Drug Safety, Drug Safety Research and Development, Pfizer Inc, Cambridge, 02140 (United States); Rossi, Annamaria [Investigative Toxicology, Drug Safety Research and Development, Pfizer Ltd, Ramsgate Road, Sandwich, CT13 9NJ (United Kingdom)

    2012-08-01

    Recent breakthroughs in stem cell biology, especially the development of the induced pluripotent stem cell techniques, have generated tremendous enthusiasm and efforts to explore the therapeutic potential of stem cells in regenerative medicine. Stem cell therapies are being considered for the treatment of degenerative diseases, inflammatory conditions, cancer and repair of damaged tissue. The safety of a stem cell therapy depends on many factors including the type of cell therapy, the differentiation status and proliferation capacity of the cells, the route of administration, the intended clinical location, long term survival of the product and/or engraftment, the need for repeated administration, the disease to be treated and the age of the population. Understanding the product profile of the intended therapy is crucial to the development of the nonclinical safety study design.

  4. Stem cells and exosomes in cardiac repair.

    Science.gov (United States)

    Singla, Dinender K

    2016-04-01

    Cardiac diseases currently lead in the number of deaths per year, giving rise an interest in transplanting embryonic and adult stem cells as a means to improve damaged tissue from conditions such as myocardial infarction and coronary artery disease. After testing these cells as a treatment option in both animal and human models, it is believed that these cells improve the damaged tissue primarily through the release of autocrine and paracrine factors. Major concerns such as teratoma formation, immune response, difficulty harvesting cells, and limited cell proliferation and differentiation, hinder the routine use of these cells as a treatment option in the clinic. The advent of stem cell-derived exosomes circumvent those concerns, while still providing the growth factors, miRNA, and additional cell protective factors that aid in repairing and regenerating the damaged tissue. These exosomes have been found to be anti-apoptotic, anti-fibrotic, pro-angiogenic, as well as enhance cardiac differentiation, all of which are key to repairing damaged tissue. As such, stem cell derived exosomes are considered to be a potential new and novel approach in the treatment of various cardiac diseases. PMID:26848944

  5. DNA damage and gene therapy of xeroderma pigmentosum, a human DNA repair-deficient disease

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Full correction of mutation in the XPC gene by engineered nucleases. • Meganucleases and TALENs are inhibited by 5-MeC for inducing double strand breaks. • Gene therapy of XP cells is possible using homologous recombination for DSB repair. - Abstract: Xeroderma pigmentosum (XP) is a genetic disease characterized by hypersensitivity to ultra-violet and a very high risk of skin cancer induction on exposed body sites. This syndrome is caused by germinal mutations on nucleotide excision repair genes. No cure is available for these patients except a complete protection from all types of UV radiations. We reviewed the various techniques to complement or to correct the genetic defect in XP cells. We, particularly, developed the correction of XP-C skin cells using the fidelity of the homologous recombination pathway during repair of double-strand break (DSB) in the presence of XPC wild type sequences. We used engineered nucleases (meganuclease or TALE nuclease) to induce a DSB located at 90 bp of the mutation to be corrected. Expression of specific TALE nuclease in the presence of a repair matrix containing a long stretch of homologous wild type XPC sequences allowed us a successful gene correction of the original TG deletion found in numerous North African XP patients. Some engineered nucleases are sensitive to epigenetic modifications, such as cytosine methylation. In case of methylated sequences to be corrected, modified nucleases or demethylation of the whole genome should be envisaged. Overall, we showed that specifically-designed TALE-nuclease allowed us to correct a 2 bp deletion in the XPC gene leading to patient's cells proficient for DNA repair and showing normal UV-sensitivity. The corrected gene is still in the same position in the human genome and under the regulation of its physiological promoter. This result is a first step toward gene therapy in XP patients

  6. DNA damage and gene therapy of xeroderma pigmentosum, a human DNA repair-deficient disease

    Energy Technology Data Exchange (ETDEWEB)

    Dupuy, Aurélie [Laboratory of Genetic Instability and Oncogenesis UMR8200CNRS, Institut Gustave Roussy and University Paris-Sud, Villejuif (France); Sarasin, Alain, E-mail: alain.sarasin@gustaveroussy.fr [Laboratory of Genetic Instability and Oncogenesis UMR8200CNRS, Institut Gustave Roussy and University Paris-Sud, Villejuif (France); Service de Génétique, Institut Gustave Roussy (France)

    2015-06-15

    Graphical abstract: - Highlights: • Full correction of mutation in the XPC gene by engineered nucleases. • Meganucleases and TALENs are inhibited by 5-MeC for inducing double strand breaks. • Gene therapy of XP cells is possible using homologous recombination for DSB repair. - Abstract: Xeroderma pigmentosum (XP) is a genetic disease characterized by hypersensitivity to ultra-violet and a very high risk of skin cancer induction on exposed body sites. This syndrome is caused by germinal mutations on nucleotide excision repair genes. No cure is available for these patients except a complete protection from all types of UV radiations. We reviewed the various techniques to complement or to correct the genetic defect in XP cells. We, particularly, developed the correction of XP-C skin cells using the fidelity of the homologous recombination pathway during repair of double-strand break (DSB) in the presence of XPC wild type sequences. We used engineered nucleases (meganuclease or TALE nuclease) to induce a DSB located at 90 bp of the mutation to be corrected. Expression of specific TALE nuclease in the presence of a repair matrix containing a long stretch of homologous wild type XPC sequences allowed us a successful gene correction of the original TG deletion found in numerous North African XP patients. Some engineered nucleases are sensitive to epigenetic modifications, such as cytosine methylation. In case of methylated sequences to be corrected, modified nucleases or demethylation of the whole genome should be envisaged. Overall, we showed that specifically-designed TALE-nuclease allowed us to correct a 2 bp deletion in the XPC gene leading to patient's cells proficient for DNA repair and showing normal UV-sensitivity. The corrected gene is still in the same position in the human genome and under the regulation of its physiological promoter. This result is a first step toward gene therapy in XP patients.

  7. Studies on the effect of low level laser therapy on bone repair

    International Nuclear Information System (INIS)

    The speed and quality of bone repair has direct clinical relevance. It has been suggested that Low Level Laser Therapy (LLLT) accelerates bone healing and that neuropeptides play a role in bone metabolism. This study investigated LLLT effects (using a GaAlAs semiconductor laser, 830 nm wavelength, 70 mW output power at an energy density of 4J/cm2) on the repair of pinned immobilised femoral osteotomies in male Sprague Dawley rats randomly assigned to 3 experimental groups: a control group, group A (osteotomised limb irradiated) and group B (non-osteotomised limb irradiated). Specimens were retrieved from 1-5 weeks post-trauma for histology, immunohistochemical investigation of neuropeptide expression (NPY, CGRP, SP, VIP), radioimmunoassay, bone mineral density (BMD) and biomechanical strength testing studies. Histology suggested accelerated bone repair in group B by 3 weeks, while by 5 weeks the control group was more advanced displaying bony union. Distinct differences were detected in the pattern and level of neuropeptide expression in repairing fractures between groups with several novel and discrete peptide localisations being reported for bone and cartilage cell types and bone marrow megakaryocytes. A role for neuropeptides in bone metabolism is supported. Bone densitometry showed no significant difference between groups for in vivo BMD data but did on more accurate in vitro assessment. Biomechanical studies demonstrated stronger osteotomies in the control group compared to irradiated groups at 5 weeks post-osteotomy suggesting that bone quality may be poorer after LLLT. The initial acceleration of bone repair after laser therapy indicates that it is biostimulatory to repair (a systemic effect was detected), however as the control group was more advanced by 5 weeks post-fracture further investigation of different treatment schedules is indicated. This research confirms that BMD is not the sole determinant of bone strength but that bone quality is clearly

  8. Comparison of repair capability of four human tumor cell lines

    International Nuclear Information System (INIS)

    A fast and reliable method for assessment of repair capacity of cells based on the restoration of transcription of the gene for the green fluorescent protein carried by a plasmid vector is presented. Repair capacity of the cells counted under fluorescent microscope 24 hours following transcription. This approach has been applied to compare the rates of repair of different types of DNA lesions in four human tumor cell lines. The analysis of the obtained results show that there are considerable differences in the repair capacity of the different cell lines towards the different types of lesions. It should be noted that the difference in repair capacity of the host cells are better evident when plasmids with lower rather that higher number of lesions per unit length of plasmid DNA are used. This is probably because the egfp genes with fewer lesions can be fully repaired while egfp genes with more lesions remain inactive even after some of the lesions have been repaired

  9. A novel cell permeable DNA replication and repair marker

    OpenAIRE

    Herce, Henry D.; Rajan, Malini; Lättig-Tünnemann, Gisela; Fillies, Marion; Cardoso, M. Cristina

    2014-01-01

    Proliferating Cell Nuclear Antigen (PCNA) is a key protein in DNA replication and repair. The dynamics of replication and repair in live cells is usually studied introducing translational fusions of PCNA. To obviate the need for transfection and bypass the problem of difficult to transfect and/or short lived cells, we have now developed a cell permeable replication and/or repair marker. The design of this marker has three essential molecular components: (1) an optimized artificial PCNA bindin...

  10. Stem Cells for Augmenting Tendon Repair

    Directory of Open Access Journals (Sweden)

    Lawrence V. Gulotta

    2012-01-01

    Full Text Available Tendon healing is fraught with complications such as reruptures and adhesion formation due to the formation of scar tissue at the injury site as opposed to the regeneration of native tissue. Stem cells are an attractive option in developing cell-based therapies to improve tendon healing. However, several questions remain to be answered before stem cells can be used clinically. Specifically, the type of stem cell, the amount of cells, and the proper combination of growth factors or mechanical stimuli to induce differentiation all remain to be seen. This paper outlines the current literature on the use of stem cells for tendon augmentation.

  11. Role of paracrine factors in stem and progenitor cell mediated cardiac repair and tissue fibrosis

    Directory of Open Access Journals (Sweden)

    Burchfield Jana S

    2008-10-01

    Full Text Available Abstract A new era has begun in the treatment of ischemic disease and heart failure. With the discovery that stem cells from diverse organs and tissues, including bone marrow, adipose tissue, umbilical cord blood, and vessel wall, have the potential to improve cardiac function beyond that of conventional pharmacological therapy comes a new field of research aiming at understanding the precise mechanisms of stem cell-mediated cardiac repair. Not only will it be important to determine the most efficacious cell population for cardiac repair, but also whether overlapping, common mechanisms exist. Increasing evidence suggests that one mechanism of action by which cells provide tissue protection and repair may involve paracrine factors, including cytokines and growth factors, released from transplanted stem cells into the surrounding tissue. These paracrine factors have the potential to directly modify the healing process in the heart, including neovascularization, cardiac myocyte apoptosis, inflammation, fibrosis, contractility, bioenergetics, and endogenous repair.

  12. Human Nerual Stem Cells for Brain Repair

    OpenAIRE

    Kim, Seung U.; Lee, Hong J.; In H Park; Chu, Kon; Lee, Soon T.; Kim, Manho; Roh, Jae K.; Kim, Seung K.; Wang, Kyu C.

    2008-01-01

    Cell replacement therapy and gene transfer to the diseased or injured brain have provided the basis for the development of potentially powerful new therapeutic strategies for a broad spectrum of human neurological diseases including Parkinson disease, Huntington disease, amyotrophic lateral sclerosis (ALS), Alzheimer disease, multiple sclerosis (MS), stroke, spinal cord injury and brain cancer. In recent years, neurons and glial cells have successfully been generated from neural stem cells, a...

  13. New design of nucleotide excision repair (NER) inhibitors for combination cancer therapy.

    Science.gov (United States)

    Gentile, Francesco; Tuszynski, Jack A; Barakat, Khaled H

    2016-04-01

    Many cancer chemotherapy agents act by targeting the DNA of cancer cells, causing substantial damage within their genome and causing them to undergo apoptosis. An effective DNA repair pathway in cancer cells can act in a reverse way by removing these drug-induced DNA lesions, allowing cancer cells to survive, grow and proliferate. In this context, DNA repair inhibitors opened a new avenue in cancer treatment, by blocking the DNA repair mechanisms from removing the chemotherapy-mediated DNA damage. In particular, the nucleotide excision repair (NER) involves more than thirty protein-protein interactions and removes DNA adducts caused by platinum-based chemotherapy. The excision repair cross-complementation group 1 (ERCC1)-xeroderma pigmentosum, complementation group A (XPA) protein (XPA-ERCC1) complex seems to be one of the most promising targets in this pathway. ERCC1 is over expressed in cancer cells and the only known cellular function so far for XPA is to recruit ERCC1 to the damaged point. Here, we build upon our recent advances in identifying inhibitors for this interaction and continue our efforts to rationally design more effective and potent regulators for the NER pathway. We employed in silico drug design techniques to: (1) identify compounds similar to the recently discovered inhibitors, but more effective at inhibiting the XPA-ERCC1 interactions, and (2) identify different scaffolds to develop novel lead compounds. Two known inhibitor structures have been used as starting points for two ligand/structure-hybrid virtual screening approaches. The findings described here form a milestone in discovering novel inhibitors for the NER pathway aiming at improving the efficacy of current platinum-based therapy, by modulating the XPA-ERCC1 interaction. PMID:26939044

  14. Repair of ultraviolet irradiation damage in mouse neuroblasts cells

    International Nuclear Information System (INIS)

    It was demonstrated, using hydroxyurea inhibition of DNA replication and CsCl density centrifugation, that excision repair occurs both in the differentiated state, and when cells have been restored to growing conditions. since the ability to remove photodamage is present, we postulated that sensitivity was due to failure to remove damage from critical regions of the genome or alternatively a deficiency in another mechanism of repair, such as post replication repair, which has been demonstrated in rodent cells. The first possibility was examined by comparing excision repair in pyrmidine tracts, in which preferential formation of dimers occurs at lower UV doses, and nontract regions. Excision repair was also determined in satellite and main band DNA. The results indicate that in the particular regions of the genome examined no preference for excision repair is detected. Post replication repair (i.e. the ability to elongate DNA which is synthesized in low molecular weight pieces after UV irradiation) was determined in growing and differentiated cells. The results show that postreplication repair is normal in differentiated cells which have entered the first S phase after serum return. since excision repair and postreplication repair appear to be normal it is possible that an additional repair process is involved or that some other cell function is irreversible damage. (author)

  15. Cell therapy of pseudarthrosis

    OpenAIRE

    Bastos Filho, Ricardo; Lermontov, Simone; Borojevic, Radovan; Schott, Paulo Cezar; Gameiro, Vinicius Schott; José Mauro GRANJEIRO

    2012-01-01

    Objective To assess the safety and efficiency of cell therapy for pseudarthrosis. Implant of the bone marrow aspirate was compared to mononuclear cells purified extemporaneously using the Sepax® equipment. Methods Six patients with nonunion of the tibia or femur were treated. Four received a percutaneous infusion of autologous bone marrow aspirated from the iliac crest, and two received autologous bone marrow mononuclear cells separated from the aspirate with the Sepax®. The primary fixation ...

  16. Acetylation regulates DNA repair mechanisms in human cells.

    Science.gov (United States)

    Piekna-Przybylska, Dorota; Bambara, Robert A; Balakrishnan, Lata

    2016-06-01

    The p300-mediated acetylation of enzymes involved in DNA repair and replication has been previously shown to stimulate or inhibit their activities in reconstituted systems. To explore the role of acetylation on DNA repair in cells we constructed plasmid substrates carrying inactivating damages in the EGFP reporter gene, which should be repaired in cells through DNA mismatch repair (MMR) or base excision repair (BER) mechanisms. We analyzed efficiency of repair within these plasmid substrates in cells exposed to deacetylase and acetyltransferase inhibitors, and also in cells deficient in p300 acetyltransferase. Our results indicate that protein acetylation improves DNA mismatch repair in MMR-proficient HeLa cells and also in MMR-deficient HCT116 cells. Moreover, results suggest that stimulated repair of mismatches in MMR-deficient HCT116 cells is done though a strand-displacement synthesis mechanism described previously for Okazaki fragments maturation and also for the EXOI-independent pathway of MMR. Loss of p300 reduced repair of mismatches in MMR-deficient cells, but did not have evident effects on BER mechanisms, including the long patch BER pathway. Hypoacetylation of the cells in the presence of acetyltransferase inhibitor, garcinol generally reduced efficiency of BER of 8-oxoG damage, indicating that some steps in the pathway are stimulated by acetylation. PMID:27104361

  17. Mismatch Repair and Colon Cancer: Mechanisms and Therapies Explored.

    Science.gov (United States)

    Li, Stephen K H; Martin, Alberto

    2016-04-01

    Colorectal cancer (CRC) remains one of the most prevalent cancers worldwide. In sporadic CRC, mutations frequently occur in the DNA mismatch repair (MMR) pathway. In addition, germline MMR mutations have been linked to Lynch syndrome, the most common form of hereditary CRC. Although genetic mutations, diet, inflammation, and the gut microbiota can influence CRC, it is unclear how MMR deficiency relates to these factors to modulate disease. In this review, the association of MMR to the etiology of CRC is examined, particularly in the context of microRNAs (miRNAs), inflammation, and the microbiome. We also discuss the most current targeted therapies, methods of prevention, and molecular biomarkers against MMR-deficient CRC, all of which are encouraging advancements in the field. PMID:26970951

  18. A stem cell-based approach to cartilage repair.

    Science.gov (United States)

    Johnson, Kristen; Zhu, Shoutian; Tremblay, Matthew S; Payette, Joshua N; Wang, Jianing; Bouchez, Laure C; Meeusen, Shelly; Althage, Alana; Cho, Charles Y; Wu, Xu; Schultz, Peter G

    2012-05-11

    Osteoarthritis (OA) is a degenerative joint disease that involves the destruction of articular cartilage and eventually leads to disability. Molecules that promote the selective differentiation of multipotent mesenchymal stem cells (MSCs) into chondrocytes may stimulate the repair of damaged cartilage. Using an image-based high-throughput screen, we identified the small molecule kartogenin, which promotes chondrocyte differentiation (median effective concentration = 100 nM), shows chondroprotective effects in vitro, and is efficacious in two OA animal models. Kartogenin binds filamin A, disrupts its interaction with the transcription factor core-binding factor β subunit (CBFβ), and induces chondrogenesis by regulating the CBFβ-RUNX1 transcriptional program. This work provides new insights into the control of chondrogenesis that may ultimately lead to a stem cell-based therapy for osteoarthritis. PMID:22491093

  19. Targeting DNA repair by coDbait enhances melanoma targeted radionuclide therapy.

    Science.gov (United States)

    Viallard, Claire; Chezal, Jean-Michel; Mishellany, Florence; Ranchon-Cole, Isabelle; Pereira, Bruno; Herbette, Aurélie; Besse, Sophie; Boudhraa, Zied; Jacquemot, Nathalie; Cayre, Anne; Miot-Noirault, Elisabeth; Sun, Jian-Sheng; Dutreix, Marie; Degoul, Françoise

    2016-03-15

    Radiolabelled melanin ligands offer an interesting strategy for the treatment of disseminated pigmented melanoma. One of these molecules, ICF01012 labelled with iodine 131, induced a significant slowing of melanoma growth. Here, we have explored the combination of [131I]ICF01012 with coDbait, a DNA repair inhibitor, to overcome melanoma radioresistance and increase targeted radionuclide therapy (TRT) efficacy. In human SK-Mel 3 melanoma xenograft, the addition of coDbait had a synergistic effect on tumor growth and median survival. The anti-tumor effect was additive in murine syngeneic B16Bl6 model whereas coDbait combination with [131I]ICF01012 did not increase TRT side effects in secondary pigmented tissues (e.g. hair follicles, eyes). Our results confirm that DNA lesions induced by TRT were not enhanced with coDbait association but, the presence of micronuclei and cell cycle blockade in tumor shows that coDbait acts by interrupting or delaying DNA repair. In this study, we demonstrate for the first time, the usefulness of DNA repair traps in the context of targeted radionuclide therapy. PMID:26887045

  20. Targeting DNA repair by coDbait enhances melanoma targeted radionuclide therapy

    Science.gov (United States)

    Viallard, Claire; Chezal, Jean-Michel; Mishellany, Florence; Ranchon-Cole, Isabelle; Pereira, Bruno; Herbette, Aurélie; Besse, Sophie; Boudhraa, Zied; Jacquemot, Nathalie; Cayre, Anne; Miot-Noirault, Elisabeth; Sun, Jian-Sheng; Dutreix, Marie; Degoul, Françoise

    2016-01-01

    Radiolabelled melanin ligands offer an interesting strategy for the treatment of disseminated pigmented melanoma. One of these molecules, ICF01012 labelled with iodine 131, induced a significant slowing of melanoma growth. Here, we have explored the combination of [131I]ICF01012 with coDbait, a DNA repair inhibitor, to overcome melanoma radioresistance and increase targeted radionuclide therapy (TRT) efficacy. In human SK-Mel 3 melanoma xenograft, the addition of coDbait had a synergistic effect on tumor growth and median survival. The anti-tumor effect was additive in murine syngeneic B16Bl6 model whereas coDbait combination with [131I]ICF01012 did not increase TRT side effects in secondary pigmented tissues (e.g. hair follicles, eyes). Our results confirm that DNA lesions induced by TRT were not enhanced with coDbait association but, the presence of micronuclei and cell cycle blockade in tumor shows that coDbait acts by interrupting or delaying DNA repair. In this study, we demonstrate for the first time, the usefulness of DNA repair traps in the context of targeted radionuclide therapy. PMID:26887045

  1. DNA damage induced by boron neutron capture therapy is partially repaired by DNA ligase IV.

    Science.gov (United States)

    Kondo, Natsuko; Sakurai, Yoshinori; Hirota, Yuki; Tanaka, Hiroki; Watanabe, Tsubasa; Nakagawa, Yosuke; Narabayashi, Masaru; Kinashi, Yuko; Miyatake, Shin-ichi; Hasegawa, Masatoshi; Suzuki, Minoru; Masunaga, Shin-ichiro; Ohnishi, Takeo; Ono, Koji

    2016-03-01

    Boron neutron capture therapy (BNCT) is a particle radiation therapy that involves the use of a thermal or epithermal neutron beam in combination with a boron ((10)B)-containing compound that specifically accumulates in tumor. (10)B captures neutrons and the resultant fission reaction produces an alpha ((4)He) particle and a recoiled lithium nucleus ((7)Li). These particles have the characteristics of high linear energy transfer (LET) radiation and therefore have marked biological effects. High-LET radiation is a potent inducer of DNA damage, specifically of DNA double-strand breaks (DSBs). The aim of the present study was to clarify the role of DNA ligase IV, a key player in the non-homologous end-joining repair pathway, in the repair of BNCT-induced DSBs. We analyzed the cellular sensitivity of the mouse embryonic fibroblast cell lines Lig4-/- p53-/- and Lig4+/+ p53-/- to irradiation using a thermal neutron beam in the presence or absence of (10)B-para-boronophenylalanine (BPA). The Lig4-/- p53-/- cell line had a higher sensitivity than the Lig4+/+ p53-/-cell line to irradiation with the beam alone or the beam in combination with BPA. In BNCT (with BPA), both cell lines exhibited a reduction of the 50 % survival dose (D 50) by a factor of 1.4 compared with gamma-ray and neutron mixed beam (without BPA). Although it was found that (10)B uptake was higher in the Lig4+/+ p53-/- than in the Lig4-/- p53-/- cell line, the latter showed higher sensitivity than the former, even when compared at an equivalent (10)B concentration. These results indicate that BNCT-induced DNA damage is partially repaired using DNA ligase IV. PMID:26573366

  2. Neural repair with pluripotent stem cells.

    Science.gov (United States)

    Döbrössy, Máté; Pruszak, Jan

    2013-01-01

    The nervous system is characterized by its complex network of highly specialized cells that enable us to perceive stimuli from the outside world and react accordingly. The computational integration enabled by these networks remains to be elucidated, but appropriate sensory input, processing, and motor control are certainly essential for survival. Consequently, loss of nervous tissue due to injury or disease represents a considerable biomedical challenge. Stem cell research offers the promise to provide cells for nervous system repair to replace lost and damaged neural tissue and alleviate disease. We provide a protocol-based chapter on fundamental principles and procedures of pluripotent stem cell (PSC) differentiation and neural transplantation. Rather than detailed methodological step-by-step descriptions of these procedures, we provide an overview and highlight the most critical aspects and key steps of PSC neural induction, subtype specification in different in vitro systems, as well as neural cell transplantation to the central nervous system. We conclude with a summary of suitable readout methods including in vitro phenotypic analysis, histology, and functional analysis in vivo. PMID:24029933

  3. Isolating human DNA repair genes using rodent-cell mutants

    International Nuclear Information System (INIS)

    The DNA repair systems of rodent and human cells appear to be at least as complex genetically as those in lower eukaryotes and bacteria. The use of mutant lines of rodent cells as a means of identifying human repair genes by functional complementation offers a new approach toward studying the role of repair in mutagenesis and carcinogenesis. In each of six cases examined using hybrid cells, specific human chromosomes have been identified that correct CHO cell mutations affecting repair of damage from uv or ionizing radiations. This finding suggests that both the repair genes and proteins may be virtually interchangeable between rodent and human cells. Using cosmid vectors, human repair genes that map to chromosome 19 have cloned as functional sequences: ERCC2 and XRCC1. ERCC1 was found to have homology with the yeast excision repair gene RAD10. Transformants of repair-deficient cell lines carrying the corresponding human gene show efficient correction of repair capacity by all criteria examined. 39 refs., 1 fig., 1 tab

  4. Stem cell-based biological tooth repair and regeneration

    OpenAIRE

    Volponi, Ana Angelova; Pang, Yvonne; Sharpe, Paul T.

    2010-01-01

    Teeth exhibit limited repair in response to damage, and dental pulp stem cells probably provide a source of cells to replace those damaged and to facilitate repair. Stem cells in other parts of the tooth, such as the periodontal ligament and growing roots, play more dynamic roles in tooth function and development. Dental stem cells can be obtained with ease, making them an attractive source of autologous stem cells for use in restoring vital pulp tissue removed because of infection, in regene...

  5. DNA repair and radiation sensitivity in mammalian cells

    International Nuclear Information System (INIS)

    Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population

  6. DNA damage and repair in human cells exposed to sunlight

    International Nuclear Information System (INIS)

    Cultured human cells were treated with direct sunlight under conditions which minimised the hypertonic, hyperthermic and fixative effects of solar radiation. Sunlight produced similar levels of DNA strand breaks as equitoxic 254 nm UV in two fibroblast strains and a melanoma cell line, but DNA repair synthesis and inhibition of semiconservative DNA synthesis and of DNA chain elongation were significantly less for sunlight-exposed cells. DNA breaks induced by sunlight were removed more rapidly. Thus, the repair of solar damage differs considerably from 254 nm UV repair. Glass-filtered sunlight (>320 nm) was not toxic to cells and did not induce repair synthesis but gave a low level of short-lived DNA breaks and some inhibition of DNA chain elongation; thymidine uptake was enhanced. Filtered sunlight slightly enhanced UV-induced repair synthesis and UV toxicity; photoreactivation of UV damage was not found. Attempts to transform human fibroblasts using sunlight, with or without phorbol ester, were unsuccessful. (author)

  7. Mutagenesis in repair-deficient human cell strains

    International Nuclear Information System (INIS)

    Cell killing and mutation experiments with a range of human skin fibroblast cell strains are described. With ultraviolet light increased sensitivity to cell killing was observed in excision-defective xeroderma pigmentosum cell strains and cells from Cockayne syndrome patients and patient 11961 from no known syndrome with no observable defects in repair. Xeroderma pigmentosum variant cells with defects in daughter strand repair did not show enhanced sensitivity. All of these cell strains were hypermutable when compared with normal cells and this allows the authors to propose that (i) excision repair may, as in bacteria, be essentially error free, (ii) daughter strand repair is error prone and (iii) additional undefined error-prone repair processes may exist. With gamma irradiation the sensitive ataxia telangiectasia cells are not hypermutable, these cells may then be defective in an error-prone repair process. Alternatively, induced mutants which have origin as chromosome deletions may prove lethal in such cells because of their susceptibility to the chromosome damaging effects of ionizing radiation. Photoreactivation was without effect on sister strand exchanges in a marsupial cell line. This result indicates that these chromosome effects are not caused by pyrimidine dimers but some other lesion. (Auth.)

  8. Embryonic and adult stem cell therapy.

    Science.gov (United States)

    Brignier, Anne C; Gewirtz, Alan M

    2010-02-01

    There are many types of stem cells. All share the characteristics of being able to self-renew and to give rise to differentiated progeny. Over the last decades, great excitement has been generated by the prospect of being able to exploit these properties for the repair, improvement, and/or replacement of damaged organs. However, many hurdles, both scientific and ethical, remain in the path of using human embryonic stem cells for tissue-engineering purposes. In this report we review current strategies for isolating, enriching, and, most recently, inducing the development of human pluripotent stem cells. In so doing, we discuss the scientific and ethical issues associated with this endeavor. Finally, progress in the use of stem cells as therapies for type 1 diabetes mellitus, congestive heart failure, and various neurologic and immunohematologic disorders, and as vehicles for the delivery of gene therapy, is briefly discussed. PMID:20061008

  9. Differential astroglial responses in the spinal cord of rats submitted to a sciatic nerve double crush treated with local injection of cultured Schwann cell suspension or lesioned spinal cord extract: implications on cell therapy for nerve repair Respostas astrocitárias na medula espinal do rato submetido ao esmagamento duplo do nervo ciático e tratado com injeção local de suspensão de células de Schwann cultivadas ou de extrato de medula espinal lesada: implicações na terapia celular para o reparo do nervo

    OpenAIRE

    João Gabriel Martins Dallo; Bernardo Vergara Reichert; José Benedito Ramos Valladão Júnior; Camila Silva; Bianca Aparecida de Luca; Beatriz de Freitas Azevedo Levy; Gerson Chadi

    2007-01-01

    PURPOSE: Reactive astrocytes are implicated in several mechanisms after central or peripheral nervous system lesion, including neuroprotection, neuronal sprouting, neurotransmission and neuropathic pain. Schwann cells (SC), a peripheral glia, also react after nerve lesion favoring wound/repair, fiber outgrowth and neuronal regeneration. We investigated herein whether cell therapy for repair of lesioned sciatic nerve may change the pattern of astroglial activation in the spinal cord ventral or...

  10. Neural stem cell transplantation in the repair of spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Neural stem cells are a pronising candidate for neural transplantation aimed at neural cell replacement and repair of the damaged host central nervous system (CNS). Recent studies using neural stem cells have shown that implanted neural stem cells can effectively incorporate into the damaged CNS and differentiate into neurons, astrocytes, and oligodendrocytes. The recent explosion in the field of neural stem cell research has provided insight into the inductive factors influencing neural stem cell differentiation and may yield potential therapies for several neurological disorders, including spinal cord injury. In this review, we summarize recent studies involving neural stem cell biology in both rodents and humans. We also discuss unique advantages and possible mechanisms of using neural stem cell trans plantation in the repair of spinal cord injury.

  11. A novel cell permeable DNA replication and repair marker.

    Science.gov (United States)

    Herce, Henry D; Rajan, Malini; Lättig-Tünnemann, Gisela; Fillies, Marion; Cardoso, M Cristina

    2014-01-01

    Proliferating Cell Nuclear Antigen (PCNA) is a key protein in DNA replication and repair. The dynamics of replication and repair in live cells is usually studied introducing translational fusions of PCNA. To obviate the need for transfection and bypass the problem of difficult to transfect and/or short lived cells, we have now developed a cell permeable replication and/or repair marker. The design of this marker has three essential molecular components: (1) an optimized artificial PCNA binding peptide; (2) a cell-penetrating peptide, derived from the HIV-1 Trans Activator of Transcription (TAT); (3) an in vivo cleavable linker, linking the two peptides. The resulting construct was taken up by human, hamster and mouse cells within minutes of addition to the media. Inside the cells, the cargo separated from the vector peptide and bound PCNA effectively. Both replication and repair sites could be directly labeled in live cells making it the first in vivo cell permeable peptide marker for these two fundamental cellular processes. Concurrently, we also introduced a quick peptide based PCNA staining method as an alternative to PCNA antibodies for immunofluorescence applications. In summary, we present here a versatile tool to instantaneously label repair and replication processes in fixed and live cells. PMID:25484186

  12. APOBEC3G enhances lymphoma cell radioresistance by promoting cytidine deaminase-dependent DNA repair.

    Science.gov (United States)

    Nowarski, Roni; Wilner, Ofer I; Cheshin, Ori; Shahar, Or D; Kenig, Edan; Baraz, Leah; Britan-Rosich, Elena; Nagler, Arnon; Harris, Reuben S; Goldberg, Michal; Willner, Itamar; Kotler, Moshe

    2012-07-12

    APOBEC3 proteins catalyze deamination of cytidines in single-stranded DNA (ssDNA), providing innate protection against retroviral replication by inducing deleterious dC > dU hypermutation of replication intermediates. APOBEC3G expression is induced in mitogen-activated lymphocytes; however, no physiologic role related to lymphoid cell proliferation has yet to be determined. Moreover, whether APOBEC3G cytidine deaminase activity transcends to processing cellular genomic DNA is unknown. Here we show that lymphoma cells expressing high APOBEC3G levels display efficient repair of genomic DNA double-strand breaks (DSBs) induced by ionizing radiation and enhanced survival of irradiated cells. APOBEC3G transiently accumulated in the nucleus in response to ionizing radiation and was recruited to DSB repair foci. Consistent with a direct role in DSB repair, inhibition of APOBEC3G expression or deaminase activity resulted in deficient DSB repair, whereas reconstitution of APOBEC3G expression in leukemia cells enhanced DSB repair. APOBEC3G activity involved processing of DNA flanking a DSB in an integrated reporter cassette. Atomic force microscopy indicated that APOBEC3G multimers associate with ssDNA termini, triggering multimer disassembly to multiple catalytic units. These results identify APOBEC3G as a prosurvival factor in lymphoma cells, marking APOBEC3G as a potential target for sensitizing lymphoma to radiation therapy. PMID:22645179

  13. In Vivo Reprogramming for CNS Repair: Regenerating Neurons from Endogenous Glial Cells.

    Science.gov (United States)

    Li, Hedong; Chen, Gong

    2016-08-17

    Neuroregeneration in the CNS has proven to be difficult despite decades of research. The old dogma that CNS neurons cannot be regenerated in the adult mammalian brain has been overturned; however, endogenous adult neurogenesis appears to be insufficient for brain repair. Stem cell therapy once held promise for generating large quantities of neurons in the CNS, but immunorejection and long-term functional integration remain major hurdles. In this Perspective, we discuss the use of in vivo reprogramming as an emerging technology to regenerate functional neurons from endogenous glial cells inside the brain and spinal cord. Besides the CNS, in vivo reprogramming has been demonstrated successfully in the pancreas, heart, and liver and may be adopted in other organs. Although challenges remain for translating this technology into clinical therapies, we anticipate that in vivo reprogramming may revolutionize regenerative medicine by using a patient's own internal cells for tissue repair. PMID:27537482

  14. Cyclosporin in cell therapy for cardiac regeneration.

    Science.gov (United States)

    Jansen Of Lorkeers, S J; Hart, E; Tang, X L; Chamuleau, M E D; Doevendans, P A; Bolli, R; Chamuleau, S A J

    2014-07-01

    Stem cell therapy is a promising strategy in promoting cardiac repair in the setting of ischemic heart disease. Clinical and preclinical studies have shown that cell therapy improves cardiac function. Whether autologous or allogeneic cells should be used, and the need for immunosuppression in non-autologous settings, is a matter of debate. Cyclosporin A (CsA) is frequently used in preclinical trials to reduce cell rejection after non-autologous cell therapy. The direct effect of CsA on the function and survival of stem cells is unclear. Furthermore, the appropriate daily dosage of CsA in animal models has not been established. In this review, we discuss the pros and cons of the use of CsA on an array of stem cells both in vitro and in vivo. Furthermore, we present a small collection of data put forth by our group supporting the efficacy and safety of a specific daily CsA dosage in a pig model. PMID:24831573

  15. Mesenchymal stem cell therapy for heart disease.

    Science.gov (United States)

    Gnecchi, Massimiliano; Danieli, Patrizia; Cervio, Elisabetta

    2012-08-19

    Mesenchymal stem cells (MSC) are adult stem cells with capacity for self-renewal and multi-lineage differentiation. Initially described in the bone marrow, MSC are also present in other organs and tissues. From a therapeutic perspective, because of their easy preparation and immunologic privilege, MSC are emerging as an extremely promising therapeutic agent for tissue regeneration and repair. Studies in animal models of myocardial infarction have demonstrated the ability of transplanted MSC to engraft and differentiate into cardiomyocytes and vascular cells. Most importantly, engrafted MSC secrete a wide array of soluble factors that mediate beneficial paracrine effects and may greatly contribute to cardiac repair. Together, these properties can be harnessed to both prevent and reverse remodeling in the ischemically injured ventricle. In proof-of-concept and phase I clinical trials, MSC therapy improved left ventricular function, induced reverse remodeling, and decreased scar size. In this review we will focus on the current understanding of MSC biology and MSC mechanism of action in cardiac repair. PMID:22521741

  16. Cell Therapies for Liver Diseases

    OpenAIRE

    Yu, Yue; Fisher, James E.; Lillegard, Joseph B.; Rodysill, Brian; Amiot, Bruce; Nyberg, Scott L.

    2012-01-01

    Cell therapies, which include bioartificial liver support and hepatocyte transplantation, have emerged as potential treatments for a variety of liver diseases. Acute liver failure (ALF), acute-on-chronic liver failure, and inherited metabolic liver diseases are examples of liver diseases that have been successfully treated with cell therapies at centers around the world. Cell therapies also have the potential for wide application in other liver diseases, including non-inherited liver diseases...

  17. Cell Therapies for Liver Diseases

    Science.gov (United States)

    Yu, Yue; Fisher, James E.; Lillegard, Joseph B.; Rodysill, Brian; Amiot, Bruce; Nyberg, Scott L.

    2011-01-01

    Cell therapies, which include bioartificial liver support and hepatocyte transplantation, have emerged as potential treatments for a variety of liver diseases. Acute liver failure (ALF), acute-on-chronic liver failure, and inherited metabolic liver diseases are examples of liver diseases that have been successfully treated with cell therapies at centers around the world. Cell therapies also have the potential for wide application in other liver diseases, including non-inherited liver diseases and liver cancer, and in improving the success of liver transplantation. Here we briefly summarize current concepts of cell therapy for liver diseases. PMID:22140063

  18. Stem cell therapy for diabetes

    OpenAIRE

    Lee, K. O.; Gan, S U; Calne, R Y

    2012-01-01

    Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced plu...

  19. Nanomedicine Approaches to Modulate Neural Stem Cells in Brain Repair.

    Science.gov (United States)

    Santos, Tiago; Boto, Carlos; Saraiva, Cláudia M; Bernardino, Liliana; Ferreira, Lino

    2016-06-01

    We explore the concept of modulating neural stem cells and their niches for brain repair using nanotechnology-based approaches. These approaches include stimulating cell proliferation, recruitment, and differentiation to functionally recover damaged areas. Nanoscale-engineered materials potentially overcome limited crossing of the blood-brain barrier, deficient drug delivery, and cell targeting. PMID:26917252

  20. 28. Embryonic and adult stem cell therapy.

    Science.gov (United States)

    Henningson, Carl T; Stanislaus, Marisha A; Gewirtz, Alan M

    2003-02-01

    Stem cells are characterized by the ability to remain undifferentiated and to self-renew. Embryonic stem cells derived from blastocysts are pluripotent (able to differentiate into many cell types). Adult stem cells, which were traditionally thought to be monopotent multipotent, or tissue restricted, have recently also been shown to have pluripotent properties. Adult bone marrow stem cells have been shown to be capable of differentiating into skeletal muscle, brain microglia and astroglia, and hepatocytes. Stem cell lines derived from both embryonic stem and embryonic germ cells (from the embryonic gonadal ridge) are pluripotent and capable of self-renewal for long periods. Therefore embryonic stem and germ cells have been widely investigated for their potential to cure diseases by repairing or replacing damaged cells and tissues. Studies in animal models have shown that transplantation of fetal, embryonic stem, or embryonic germ cells may be able to treat some chronic diseases. In this review, we highlight recent developments in the use of stem cells as therapeutic agents for three such diseases: Diabetes, Parkinson disease, and congestive heart failure. We also discuss the potential use of stem cells as gene therapy delivery cells and the scientific and ethical issues that arise with the use of human stem cells. PMID:12592319

  1. Brain necrosis after fractionated radiation therapy: Is the halftime for repair longer than we thought?

    International Nuclear Information System (INIS)

    Purpose: To derive a radiobiological model that enables the estimation of brain necrosis and spinal cord myelopathy rates for a variety of fractionation schemes, and to compare repair effects between brain and spinal cord. Methods: Sigmoidal dose response relationships for brain radiation necrosis and spinal cord myelopathy are derived from clinical data using nonlinear regression. Three different repair models are considered and the repair halftimes are included as regression parameters. Results: For radiation necrosis, a repair halftime of 38.1 (range 6.9–76) h is found with monoexponential repair, while for spinal cord myelopathy, a repair halftime of 4.1 (range 0–8) h is found. The best-fit alpha beta ratio is 0.96 (range 0.24–1.73)Conclusions: A radiobiological model that includes repair corrections can describe the clinical data for a variety of fraction sizes, fractionation schedules, and total doses. Modeling suggests a relatively long repair halftime for brain necrosis. This study suggests that the repair halftime for late radiation effects in the brain may be longer than is currently thought. If confirmed in future studies, this may lead to a re-evaluation of radiation fractionation schedules for some CNS diseases, particularly for those diseases where fractionated stereotactic radiation therapy is used.

  2. Brain necrosis after fractionated radiation therapy: Is the halftime for repair longer than we thought?

    Energy Technology Data Exchange (ETDEWEB)

    Bender, Edward T. [Department of Human Oncology, University of Wisconsin-Madison, School of Medicine and Public Health, 600 Highland Avenue, Madison, Wisconsin 53792 (United States)

    2012-11-15

    Purpose: To derive a radiobiological model that enables the estimation of brain necrosis and spinal cord myelopathy rates for a variety of fractionation schemes, and to compare repair effects between brain and spinal cord. Methods: Sigmoidal dose response relationships for brain radiation necrosis and spinal cord myelopathy are derived from clinical data using nonlinear regression. Three different repair models are considered and the repair halftimes are included as regression parameters. Results: For radiation necrosis, a repair halftime of 38.1 (range 6.9-76) h is found with monoexponential repair, while for spinal cord myelopathy, a repair halftime of 4.1 (range 0-8) h is found. The best-fit alpha beta ratio is 0.96 (range 0.24-1.73)Conclusions: A radiobiological model that includes repair corrections can describe the clinical data for a variety of fraction sizes, fractionation schedules, and total doses. Modeling suggests a relatively long repair halftime for brain necrosis. This study suggests that the repair halftime for late radiation effects in the brain may be longer than is currently thought. If confirmed in future studies, this may lead to a re-evaluation of radiation fractionation schedules for some CNS diseases, particularly for those diseases where fractionated stereotactic radiation therapy is used.

  3. A REVIEW OF GENE AND STEM CELL THERAPY IN CUTANEOUS WOUND HEALING

    OpenAIRE

    Branski, Ludwik K.; Gauglitz, Gerd G; Herndon, David N.; Jeschke, Marc G.

    2008-01-01

    Different therapies that modulate wound repair have been proposed over the last few decades. This article reviews the two emerging fields of gene and stem cell therapy in wound healing. Gene therapy, initially developed for treatment of congenital defects, is a new option for enhancing wound repair. In order to accelerate wound closure, genes encoding for growth factors or cytokines have showed the most potential. The majority of gene delivery systems are based on viral transfection, naked DN...

  4. Repair of tracheal epithelium by basal cells after chlorine-induced injury

    Directory of Open Access Journals (Sweden)

    Musah Sadiatu

    2012-11-01

    The data are consistent with a model where surviving basal cells function as progenitor cells to repopulate the tracheal epithelium after chlorine injury. In areas with few remaining basal cells, repair is inefficient, leading to airway fibrosis. These studies establish a model for understanding regenerative processes in the respiratory epithelium useful for testing therapies for airway injury.

  5. Stem cells in endodontic therapy

    Directory of Open Access Journals (Sweden)

    Sita Rama Kumar M, Madhu Varma K, Kalyan Satish R, Manikya kumar Nanduri.R, Murali Krishnam Raju S, Mohan rao

    2014-11-01

    Full Text Available Stem cells have the remarkable potential to develop into many different cell types in the body. Serving as a sort of repair system for the body, they can theoretically divide without limit to replenish other cells as long as the person or animal is still alive. However, progress in stem cell biology and tissue engineering may present new options for replacing heavily damaged or lost teeth, or even individual tooth structures. The goal of this review is to discuss the potential impact of dental pulp stem cells on regenerative endodontics.

  6. An update on targeted gene repair in mammalian cells: methods and mechanisms

    OpenAIRE

    Bolund Lars; Sørensen Charlotte B; Nielsen Roni R; Jakobsen Maria; Dalsgaard Trine; Jensen Nanna M; Jensen Thomas G

    2011-01-01

    Abstract Transfer of full-length genes including regulatory elements has been the preferred gene therapy strategy for clinical applications. However, with significant drawbacks emerging, targeted gene alteration (TGA) has recently become a promising alternative to this method. By means of TGA, endogenous DNA repair pathways of the cell are activated leading to specific genetic correction of single-base mutations in the genome. This strategy can be implemented using single-stranded oligodeoxyr...

  7. Cell-based therapies and imaging in cardiology

    Energy Technology Data Exchange (ETDEWEB)

    Bengel, Frank M. [Technische Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Munich (Germany); Schachinger, Volker; Dimmeler, Stefanie [University of Frankfurt, Department of Molecular Cardiology, Frankfurt (Germany)

    2005-12-01

    Cell therapy for cardiac repair has emerged as one of the most exciting and promising developments in cardiovascular medicine. Evidence from experimental and clinical studies is increasing that this innovative treatment will influence clinical practice in the future. But open questions and controversies with regard to the basic mechanisms of this therapy continue to exist and emphasise the need for specific techniques to visualise the mechanisms and success of therapy in vivo. Several non-invasive imaging approaches which aim at tracking of transplanted cells in the heart have been introduced. Among these are direct labelling of cells with radionuclides or paramagnetic agents, and the use of reporter genes for imaging of cell transplantation and differentiation. Initial studies have suggested that these molecular imaging techniques have great potential. Integration of cell imaging into studies of cardiac cell therapy holds promise to facilitate further growth of the field towards a broadly clinically useful application. (orig.)

  8. Bone marrow stromal cell : mediated neuroprotection for spinal cord repair

    NARCIS (Netherlands)

    Ritfeld, Gaby Jane

    2014-01-01

    Currently, there is no treatment available that restores anatomy and function after spinal cord injury. This thesis explores transplantation of bone marrow-derived mesenchymal stem cells (bone marrow stromal cells; BMSCs) as a therapeutic approach for spinal cord repair. BMSCs secrete neurotrophic f

  9. Stem cell therapy for diabetes

    Directory of Open Access Journals (Sweden)

    K O Lee

    2012-01-01

    Full Text Available Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells, umbilical cord stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Recent advances in stem cell therapy may turn this into a realistic treatment for diabetes in the near future.

  10. Potentials of Endogenous Neural Stem cells in Cortical Repair

    Directory of Open Access Journals (Sweden)

    Bhaskar eSaha

    2012-04-01

    Full Text Available In the last few decades great thrust has been put in the area of regenerative neurobiology research to combat brain injuries and neurodegenerative diseases. The recent discovery of neurogenic niches in the adult brain has led researchers to study how to mobilize these cells to orchestrate an endogenous repair mechanism. The brain can minimize injury-induced damage by means of an immediate glial response and by initiating repair mechanisms that involve the generation and mobilization of new neurons to the site of injury where they can integrate into the existing circuit. This review highlights the current status of research in this field. Here, we discuss the changes that take place in the neurogenic milieu following injury. We will focus, in particular, on the cellular and molecular controls that lead to increased proliferation in the Sub ventricular Zone (SVZ as well as neurogenesis. We will also concentrate on how these cellular and molecular mechanisms influence the migration of new cells to the affected area and their differentiation into neuronal/glial lineage that initiate the repair mechanism. Next, we will discuss some of the different factors that limit/retard the repair process and highlight future lines of research that can help to overcome these limitations. A clear understanding of the underlying molecular mechanisms and physiological changes following brain damage and the subsequent endogenous repair should help us develop better strategies to repair damaged brains.

  11. Stem cell therapy: From bench to bedside

    International Nuclear Information System (INIS)

    Several countries have increased efforts to develop medical countermeasures to protect against radiation toxicity due to acts of bio-terrorism as well as cancer treatment. Both acute radiation injuries and delayed effects such as cutaneous effects and impaired wound repair depend, to some extent, on angiogenesis deficiency. Vascular damage influences levels of nutrients, oxygen available to skin tissue and epithelial cell viability. Consequently, the evolution of radiation lesions often becomes uncontrolled and surgery is the final option-amputation leading to a disability. Therefore, the development of strategies designed to promote healing of radiation injuries is a major therapeutic challenge. Adult mesenchymal stem cell therapy has been combined with surgery in some cases and not in others and successfully applied in patients with accidental radiation injuries. Although research in the field of radiation skin injury management has made substantial progress in the past 10 y, several strategies are still needed in order to enhance the beneficial effect of stem cell therapy and to counteract the deleterious effect of an irradiated tissue environment. This review summarises the current and evolving advances concerning basic and translational research based on stem cell therapy for the management of radiological burns. (authors)

  12. Cell Therapy for Cardiovascular Regeneration

    OpenAIRE

    Takehara, Naofumi

    2013-01-01

    A great numbers of cardiovascular disease patients all over the world are suffering in the poor outcomes. Under this situation, cardiac regeneration therapy to reorganize the postnatal heart that is defined as a terminal differentiated-organ is a very important theme and mission for human beings. However, the temporary success of several clinical trials using usual cell types with uncertain cell numbers has provided the transient effect of cell therapy to these patients. We therefore should r...

  13. Somatic cell genetics approach to dissecting mammalian DNA repair

    International Nuclear Information System (INIS)

    This review article examines the application of the methods and concepts of somatic cell genetics to the study of DNA repair. The first steps of this approach involve classical procedures of mutant isolation, complementation analysis, and mapping of genes using hybrid cells. Subsequent steps utilize the techniques of DNA-mediated gene transfer and methodologies of the recombinant DNA field. Several human repair genes have been cloned, but they have not been used to overproduce proteins thus far. This article highlights the more important developments and attempts to review in detail all of the isolated mutant cell lines that may be altered in the repair processes. Faster methods of gene cloning are greatly needed because the procedures for making secondary transformants from total genomic DNA are tedious

  14. Molecular Imaging in Stem Cell Therapy for Spinal Cord Injury

    Directory of Open Access Journals (Sweden)

    Fahuan Song

    2014-01-01

    Full Text Available Spinal cord injury (SCI is a serious disease of the center nervous system (CNS. It is a devastating injury with sudden loss of motor, sensory, and autonomic function distal to the level of trauma and produces great personal and societal costs. Currently, there are no remarkable effective therapies for the treatment of SCI. Compared to traditional treatment methods, stem cell transplantation therapy holds potential for repair and functional plasticity after SCI. However, the mechanism of stem cell therapy for SCI remains largely unknown and obscure partly due to the lack of efficient stem cell trafficking methods. Molecular imaging technology including positron emission tomography (PET, magnetic resonance imaging (MRI, optical imaging (i.e., bioluminescence imaging (BLI gives the hope to complete the knowledge concerning basic stem cell biology survival, migration, differentiation, and integration in real time when transplanted into damaged spinal cord. In this paper, we mainly review the molecular imaging technology in stem cell therapy for SCI.

  15. Human Cardiac Tissue Engineering: From Pluripotent Stem Cells to Heart Repair

    Science.gov (United States)

    Jackman, Christopher P.; Shadrin, Ilya Y.; Carlson, Aaron L.; Bursac, Nenad

    2014-01-01

    Engineered cardiac tissues hold great promise for use in drug and toxicology screening, in vitro studies of human physiology and disease, and as transplantable tissue grafts for myocardial repair. In this review, we discuss recent progress in cell-based therapy and functional tissue engineering using pluripotent stem cell-derived cardiomyocytes and we describe methods for delivery of cells into the injured heart. While significant hurdles remain, notable advances have been made in the methods to derive large numbers of pure human cardiomyocytes, mature their phenotype, and produce and implant functional cardiac tissues, bringing the field a step closer to widespread in vitro and in vivo applications. PMID:25599018

  16. Strategies to Optimize Adult Stem Cell Therapy for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Shan Liu

    2016-06-01

    Full Text Available Stem cell therapy aims to replace damaged or aged cells with healthy functioning cells in congenital defects, tissue injuries, autoimmune disorders, and neurogenic degenerative diseases. Among various types of stem cells, adult stem cells (i.e., tissue-specific stem cells commit to becoming the functional cells from their tissue of origin. These cells are the most commonly used in cell-based therapy since they do not confer risk of teratomas, do not require fetal stem cell maneuvers and thus are free of ethical concerns, and they confer low immunogenicity (even if allogenous. The goal of this review is to summarize the current state of the art and advances in using stem cell therapy for tissue repair in solid organs. Here we address key factors in cell preparation, such as the source of adult stem cells, optimal cell types for implantation (universal mesenchymal stem cells vs. tissue-specific stem cells, or induced vs. non-induced stem cells, early or late passages of stem cells, stem cells with endogenous or exogenous growth factors, preconditioning of stem cells (hypoxia, growth factors, or conditioned medium, using various controlled release systems to deliver growth factors with hydrogels or microspheres to provide apposite interactions of stem cells and their niche. We also review several approaches of cell delivery that affect the outcomes of cell therapy, including the appropriate routes of cell administration (systemic, intravenous, or intraperitoneal vs. local administration, timing for cell therapy (immediate vs. a few days after injury, single injection of a large number of cells vs. multiple smaller injections, a single site for injection vs. multiple sites and use of rodents vs. larger animal models. Future directions of stem cell-based therapies are also discussed to guide potential clinical applications.

  17. Strategies to Optimize Adult Stem Cell Therapy for Tissue Regeneration

    Science.gov (United States)

    Liu, Shan; Zhou, Jingli; Zhang, Xuan; Liu, Yang; Chen, Jin; Hu, Bo; Song, Jinlin; Zhang, Yuanyuan

    2016-01-01

    Stem cell therapy aims to replace damaged or aged cells with healthy functioning cells in congenital defects, tissue injuries, autoimmune disorders, and neurogenic degenerative diseases. Among various types of stem cells, adult stem cells (i.e., tissue-specific stem cells) commit to becoming the functional cells from their tissue of origin. These cells are the most commonly used in cell-based therapy since they do not confer risk of teratomas, do not require fetal stem cell maneuvers and thus are free of ethical concerns, and they confer low immunogenicity (even if allogenous). The goal of this review is to summarize the current state of the art and advances in using stem cell therapy for tissue repair in solid organs. Here we address key factors in cell preparation, such as the source of adult stem cells, optimal cell types for implantation (universal mesenchymal stem cells vs. tissue-specific stem cells, or induced vs. non-induced stem cells), early or late passages of stem cells, stem cells with endogenous or exogenous growth factors, preconditioning of stem cells (hypoxia, growth factors, or conditioned medium), using various controlled release systems to deliver growth factors with hydrogels or microspheres to provide apposite interactions of stem cells and their niche. We also review several approaches of cell delivery that affect the outcomes of cell therapy, including the appropriate routes of cell administration (systemic, intravenous, or intraperitoneal vs. local administration), timing for cell therapy (immediate vs. a few days after injury), single injection of a large number of cells vs. multiple smaller injections, a single site for injection vs. multiple sites and use of rodents vs. larger animal models. Future directions of stem cell-based therapies are also discussed to guide potential clinical applications. PMID:27338364

  18. An update on targeted gene repair in mammalian cells: methods and mechanisms.

    Science.gov (United States)

    Jensen, Nanna M; Dalsgaard, Trine; Jakobsen, Maria; Nielsen, Roni R; Sørensen, Charlotte B; Bolund, Lars; Jensen, Thomas G

    2011-01-01

    Transfer of full-length genes including regulatory elements has been the preferred gene therapy strategy for clinical applications. However, with significant drawbacks emerging, targeted gene alteration (TGA) has recently become a promising alternative to this method. By means of TGA, endogenous DNA repair pathways of the cell are activated leading to specific genetic correction of single-base mutations in the genome. This strategy can be implemented using single-stranded oligodeoxyribonucleotides (ssODNs), small DNA fragments (SDFs), triplex-forming oligonucleotides (TFOs), adeno-associated virus vectors (AAVs) and zinc-finger nucleases (ZFNs). Despite difficulties in the use of TGA, including lack of knowledge on the repair mechanisms stimulated by the individual methods, the field holds great promise for the future. The objective of this review is to summarize and evaluate the different methods that exist within this particular area of human gene therapy research. PMID:21284895

  19. An update on targeted gene repair in mammalian cells: methods and mechanisms

    Directory of Open Access Journals (Sweden)

    Bolund Lars

    2011-02-01

    Full Text Available Abstract Transfer of full-length genes including regulatory elements has been the preferred gene therapy strategy for clinical applications. However, with significant drawbacks emerging, targeted gene alteration (TGA has recently become a promising alternative to this method. By means of TGA, endogenous DNA repair pathways of the cell are activated leading to specific genetic correction of single-base mutations in the genome. This strategy can be implemented using single-stranded oligodeoxyribonucleotides (ssODNs, small DNA fragments (SDFs, triplex-forming oligonucleotides (TFOs, adeno-associated virus vectors (AAVs and zinc-finger nucleases (ZFNs. Despite difficulties in the use of TGA, including lack of knowledge on the repair mechanisms stimulated by the individual methods, the field holds great promise for the future. The objective of this review is to summarize and evaluate the different methods that exist within this particular area of human gene therapy research.

  20. Stem cell therapy independent of stemness.

    Science.gov (United States)

    Lee, Techung

    2012-12-26

    Mesenchymal stem cell (MSC) therapy is entering a new era shifting the focus from initial feasibility study to optimization of therapeutic efficacy. However, how MSC therapy facilitates tissue regeneration remains incompletely characterized. Consistent with the emerging notion that secretion of multiple growth factors/cytokines (trophic factors) by MSC provides the underlying tissue regenerative mechanism, the recent study by Bai et al demonstrated a critical therapeutic role of MSC-derived hepatocyte growth factor (HGF) in two animal models of multiple sclerosis (MS), which is a progressive autoimmune disorder caused by damage to the myelin sheath and loss of oligodendrocytes. Although current MS therapies are directed toward attenuation of the immune response, robust repair of myelin sheath likely requires a regenerative approach focusing on long-term replacement of the lost oligodendrocytes. This approach appears feasible because adult organs contain various populations of multipotent resident stem/progenitor cells that may be activated by MSC trophic factors as demonstrated by Bai et al This commentary highlights and discusses the major findings of their studies, emphasizing the anti-inflammatory function and trophic cross-talk mechanisms mediated by HGF and other MSC-derived trophic factors in sustaining the treatment benefits. Identification of multiple functionally synergistic trophic factors, such as HGF and vascular endothelial growth factor, can eventually lead to the development of efficacious cell-free therapeutic regimens targeting a broad spectrum of degenerative conditions. PMID:23516128

  1. nduced pluripotent stem cells and cell therapy

    Directory of Open Access Journals (Sweden)

    Banu İskender

    2013-12-01

    Full Text Available Human embryonic stem cells are derived from the inner cell mass of a blastocyst-stage embryo. They hold a huge promise for cell therapy with their self-renewing ability and pluripotency, which is known as the potential to differentiate into all cell types originating from three embryonic germ layers. However, their unique pluripotent feature could not be utilised for therapeutic purposes due to the ethical and legal problems during derivation. Recently, it was shown that the cells from adult tissues could be reverted into embryonic state, thereby restoring their pluripotent feature. This has strenghtened the possiblity of directed differentition of the reprogrammed somatic cells into the desired cell types in vitro and their use in regenerative medicine. Although these cells were termed as induced pluripotent cells, the mechanism of pluripotency has yet to be understood. Still, induced pluripotent stem cell technology is considered to be significant by proposing novel approaches in disease modelling, drug screening and cell therapy. Besides their self-renewing ability and their potential to differentiate into all cell types in a human body, they arouse a great interest in scientific world by being far from the ethical concerns regarding their embryonic counterparts and their unique feature of being patient-specific in prospective cell therapies. In this review, induced pluripotent stem cell technology and its role in cell-based therapies from past to present will be discussed. J Clin Exp Invest 2013; 4 (4: 550-561

  2. STEM CELL-PAVED BIOBRIDGE FACILITATES NEURAL REPAIR IN TRAUMATIC BRAIN INJURY

    Directory of Open Access Journals (Sweden)

    Ernest Yankee

    2014-06-01

    Full Text Available Modified mesenchymal stromal cells (MSCs display a unique mechanism of action during the repair phase of traumatic brain injury by exhibiting the ability to build a biobridge between the neurogenic niche and the site of injury. Immunohistochemistry and laser capture assay have visualized this biobridge in the area between the neurogenic subventricular zone and the injured cortex. This biobridge expresses high levels of extracellular matrixmetalloproteinases (MMPs, which are initially co-localized with a stream of transplanted MSCs, but later this region contains only few to non-detectable grafts and becomes overgrown by newly recruited host cells. We have reported that long-distance migration of host cells from the neurogenic niche to the injured brain site can be attained via these transplanted stem cell-paved biobridges, which serve as a key regenerative process for the initiation of endogenous repair mechanisms. Thus far the two major schools of discipline in stem cell repair mechanisms support the idea of “cell replacement” and the bystander effects of “trophic factor secretion.” Our novel observation of stem cell-paved biobridges as pathways for directed migration of host cells from neurogenic niche towards the injured brain site adds another mode of action underlying stem cell therapy. More in-depth investigations on graft-host interaction will likely aid translational research focused on advancing this stem cell-paved biobridge from its current place, as an equally potent repair mechanism as cell replacement and trophic factor secretion, into a new treatment strategy for traumatic brain injury and other neurological disorders.

  3. Bone marrow stromal cell: mediated neuroprotection for spinal cord repair

    OpenAIRE

    Ritfeld, Gaby Jane

    2014-01-01

    Currently, there is no treatment available that restores anatomy and function after spinal cord injury. This thesis explores transplantation of bone marrow-derived mesenchymal stem cells (bone marrow stromal cells; BMSCs) as a therapeutic approach for spinal cord repair. BMSCs secrete neurotrophic factors, enabling neuroprotection/tissue sparing in a rat model of spinal cord injury. In this model system, bone marrow stromal cell-mediated tissue sparing leads to motor and sensory function impr...

  4. Gene manipulated peritoneal cell patch repairs infarcted myocardium

    OpenAIRE

    Huang, Wei; Zhang, Dongsheng; Millard, Ronald W.; Wang, Tao; Zhao, Tiemin; Fan, Guo-Chang; Ashraf, Atif; Xu, Meifeng; ASHRAF, Muhammad; Wang, Yigang

    2009-01-01

    A gene manipulated cell patch using a homologous peritoneum substrate was developed and applied after myocardial infarction to repair scarred myocardium. We genetically engineered male rat mesenchymal stem cells (MSC) using adenoviral transduction to over-express CXCR4/green fluorescent protein (GFP) (MSCCXCR4) or MSCNull or siRNA targeting CXCR4 (MSCsiRNA). Gene expression was studied by real-time quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA). Cells were cultured on e...

  5. Endogenous Cartilage Repair by Recruitment of Stem Cells.

    Science.gov (United States)

    Im, Gun-Il

    2016-04-01

    Articular cartilage has a very limited capacity for repair after injury. The adult body has a pool of stem cells that are mobilized during injury or disease. These cells exist inside niches in bone marrow, muscle, adipose tissue, synovium, and other connective tissues. A method that mobilizes this endogenous pool of stem cells will provide a less costly and less invasive alternative if these cells successfully regenerate defective cartilage. Traditional microfracture procedures employ the concept of bone marrow stimulation to regenerate cartilage. However, the regenerated tissue usually is fibrous cartilage, which has very poor mechanical properties compared to those of normal hyaline cartilage. A method that directs the migration of a large number of autologous mesenchymal stem cells toward injury sites, retains these cells around the defects, and induces chondrogenic differentiation that would enhance success of endogenous cartilage repair. This review briefly summarizes chemokines and growth factors that induce recruitment, proliferation, and differentiation of endogenous progenitor cells, endogenous cell sources for regenerating cartilage, scaffolds for delivery of bioactive factors, and bioadhesive materials that are necessary to bring about endogenous cartilage repair. PMID:26559963

  6. Ku80-deleted cells are defective at base excision repair

    Energy Technology Data Exchange (ETDEWEB)

    Li, Han [The University of Texas Health Science Center at San Antonio, The Institute of Biotechnology, The Department of Molecular Medicine, 15355 Lambda Drive, San Antonio, TX 78245-3207 (United States); Tumor Suppression Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029 (Spain); Marple, Teresa [The University of Texas Health Science Center at San Antonio, The Institute of Biotechnology, The Department of Molecular Medicine, 15355 Lambda Drive, San Antonio, TX 78245-3207 (United States); Hasty, Paul, E-mail: hastye@uthscsa.edu [The University of Texas Health Science Center at San Antonio, The Institute of Biotechnology, The Department of Molecular Medicine, 15355 Lambda Drive, San Antonio, TX 78245-3207 (United States); Tumor Suppression Group, Spanish National Cancer Research Centre (CNIO), Madrid 28029 (Spain)

    2013-05-15

    Graphical abstract: - Highlights: • Ku80-deleted cells are hypersensitive to ROS and alkylating agents. • Cells deleted for Ku80, but not Ku70 or Lig4, have reduced BER capacity. • OGG1 rescues hypersensitivity to H{sub 2}O{sub 2} and paraquat in Ku80-mutant cells. • Cells deleted for Ku80, but not Lig4, are defective at repairing AP sites. • Cells deleted for Ku80, but not Lig4 or Brca2 exon 27, exhibit increased PAR. - Abstract: Ku80 forms a heterodimer with Ku70, called Ku, that repairs DNA double-strand breaks (DSBs) via the nonhomologous end joining (NHEJ) pathway. As a consequence of deleting NHEJ, Ku80-mutant cells are hypersensitive to agents that cause DNA DSBs like ionizing radiation. Here we show that Ku80 deletion also decreased resistance to ROS and alkylating agents that typically cause base lesions and single-strand breaks (SSBs). This is unusual since base excision repair (BER), not NHEJ, typically repairs these types of lesions. However, we show that deletion of another NHEJ protein, DNA ligase IV (Lig4), did not cause hypersensitivity to these agents. In addition, the ROS and alkylating agents did not induce γ-H2AX foci that are diagnostic of DSBs. Furthermore, deletion of Ku80, but not Lig4 or Ku70, reduced BER capacity. Ku80 deletion also impaired BER at the initial lesion recognition/strand scission step; thus, involvement of a DSB is unlikely. Therefore, our data suggests that Ku80 deletion impairs BER via a mechanism that does not repair DSBs.

  7. Chromatin factors affecting DNA repair in mammalian cell nuclei

    International Nuclear Information System (INIS)

    We are investigating chromatin factors that participate in the incision step of DNA repair in eukaryotic cells. Localization of repair activity within nuclei, the stability and extractability of activity, the specificity for recognizing damage in chromatin or purified DNA as substrates are of interest in this investigation of human cells, CHO cells, and their radiation sensitive mutants. We have developed procedures that provide nuclei in which their DNA behaves as a collection of circular molecules. The integrity of the DNA in human nuclei can be maintained during incubation in appropriate buffers for as long as 60 minutes. When cells or nuclei are exposed to uv light prior to incubation, incisions presumably associated with DNA repair can be demonstrated. Incision activity is stable to prior extraction of nuclei with 0.6 M NaCl, which removes many nonhistone proteins. Our studies are consistent with an hypothesis that factors responsible for initiating DNA repair are localized in the nuclear matrix. 18 references, 3 figures

  8. Repair of defects in photoactive layer of organic solar cells

    NARCIS (Netherlands)

    Oostra, A.J.; Blom, P.W.M.; Michels, J.J.

    2015-01-01

    Defects occurring during printing of the photoactive layer in organic solar cells lead to short-circuits due to direct contact between the PEDOT:PSS anode and metallic cathode. We provide a highly effective repair method where the defected zone with bare PEDOT:PSS is treated with aqueous sodium hypo

  9. Radioimmunoassay studies on repair of ultraviolet damaged DNA in cultured animal cells

    International Nuclear Information System (INIS)

    UV (ultraviolet) damaged DNA and its repair of various cultured animal cells were observed by radioimmunoassay using anti-serum against the UV irradiation induced heat-degenerated DNA. There is some difference among the cells of used animals according to their DNA repairabilities. The cells were divided into four groups according to the existence or strength of their repairabilities. 1) excision repair type: cells of men and chimpanzees. 2) photoreactivation type: cells derived from Tachydromus tachydromoides and chicks. 3) photoreactivation with excision repair: cells of rats, kangaroos and mosquitos. 4) non-excision repair type: cells of mice, Meriones and rats. Animal cells have plural types of repair. Main types of repair will differ according to the kind of animals. (Ichikawa, K.)

  10. Ku80-Deleted Cells are Defective at Base Excision Repair

    OpenAIRE

    Li, Han; Marple, Teresa; Hasty, Paul

    2013-01-01

    Ku80 forms a heterodimer with Ku70, called Ku, that repairs DNA double-strand breaks (DSBs) via the nonhomologous end joining (NHEJ) pathway. As a consequence of deleting NHEJ, Ku80-mutant cells are hypersensitive to agents that cause DNA DSBs like ionizing radiation. Here we show that Ku80 deletion also decreased resistance to ROS and alkylating agents that typically cause base lesions and single-strand breaks (SSBs). This is unusual since base excision repair (BER), not NHEJ, typically repa...

  11. HCMV-infected cells maintain efficient nucleotide excision repair of the viral genome while abrogating repair of the host genome.

    Directory of Open Access Journals (Sweden)

    John M O'Dowd

    Full Text Available Many viruses subvert the host cell's ability to mount and complete various DNA damage responses (DDRs after infection. HCMV infection of permissive fibroblasts activates host DDRs at the time of viral deposition and during replication, but the DDRs remain uncompleted without arrest or apoptosis. We believe this was in part due to partitioning of the damage response and double strand break repair components. After extraction of soluble proteins, the localization of these components fell into three groups: specifically associated with the viral replication centers (RCs, diffused throughout the nucleoplasm and excluded from the RCs. Others have shown that cells are incapable of processing exogenously introduced damage after infection. We hypothesized that the inability of the cells to process damage might be due to the differential association of repair components within the RCs and, in turn, potentially preferential repair of the viral genome and compromised repair of the host genome. To test this hypothesis we used multiple strategies to examine repair of UV-induced DNA damage in mock and virus-infected fibroblasts. Comet assays indicated that repair was initiated, but was not completed in infected cells. Quantitative analysis of immunofluorescent localization of cyclobutane pyrimidine dimers (CPDs revealed that after 24 h of repair, CPDs were significantly reduced in viral DNA, but not significantly changed in the infected host DNA. To further quantitate CPD repair, we developed a novel dual-color Southern protocol allowing visualization of host and viral DNA simultaneously. Combining this Southern methodology with a CPD-specific T4 endonuclease V alkaline agarose assay to quantitate repair of adducts, we found efficient repair of CPDs from the viral DNA but not host cellular DNA. Our data confirm that NER functions in HCMV-infected cells and almost exclusively repairs the viral genome to the detriment of the host's genome.

  12. Gene therapy and peripheral nerve repair: a perspective

    OpenAIRE

    Hoyng, Stefan A.; de Winter, Fred; Tannemaat, Martijn R.; Blits, Bas; Malessy, Martijn J. A.; Verhaagen, Joost

    2015-01-01

    Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan’s, Parkinson’s (PD) and Alzheimer’s disease (AD), retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral vectors (AAV) and the first AAV-based therapeutic, a vector encoding lipoprotein lipase, is now marketed in Europe under the name Glybera. These remarkable advances may become relevant to translati...

  13. Gene therapy and peripheral nerve repair: a perspective

    OpenAIRE

    Fred De Winter; Tannemaat, Martijn R.; Bas Blits; Joost Verhaagen

    2015-01-01

    Clinical phase I/II studies have demonstrated the safety of gene therapy for a variety of central nervous system disorders, including Canavan’s, Parkinson’s and Alzheimer’s disease, retinal diseases and pain. The majority of gene therapy studies in the CNS have used adeno-associated viral vectors (AAV) and the first AAV-based therapeutic, a vector encoding lipoprotein lipase, is now marketed in Europe under the name Glybera. These remarkable advances may become relevant to translational resea...

  14. Application of Allogeneic Fibroblast Cells in Cellular Therapy of Recessive Dystrophic Epidermolysis Bullosa

    OpenAIRE

    MR Zare; Ahmadi; Rostamzadeh; Kurd; Hejazi; Fard; Anjomshoa; Nilforoushzadeh

    2015-01-01

    Context Connective tissue cells include fibroblasts, chondrocytes, adipocyte, and osteocytes. These cells are specialized for the secretion of collagenous extracellular matrix and are responsible for the architectural framework of the human body. Evidence Acquisition Connective tissue cells play a central role in supporting as well as repairing tissues and organs. Fibroblast cell therapy could be used for the treatment of burn wou...

  15. Rapid repair of potentially lethal damage in normal and ataxia telangiectasia cell lines

    International Nuclear Information System (INIS)

    Potentially lethal damage repair (PLDR) was investigated in two normal and three ataxia telangiectasia (AT) human-skin fibroblast cell lines cultured in vitro. Using plateau-phase cells, time kinetics and repair were measured after irradiation. PLDR depended on both dose and survival level, as previously seen in rodent cells. Human cells differed from rodent cells in PLDR speed and ability to discern two components within the repair response. Fast repair had a t1/2 of approximately 5-7 min; the slow response occurred over hours. AT cells had demonstrable PLDR contrasting previous studies. Quantitatively, the proportion of fast and slow repair was similar for each dose in either normal or AT cells. However, AT cells had lower levels of both types of repair. When analyzing PLDR in human cells, differences in repair rates between human and rodent cells must be considered. (author)

  16. Regulation of MUTYH, a DNA Repair Enzyme, in Renal Proximal Tubular Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Jianping Lu

    2015-01-01

    Full Text Available MUTYH is a DNA repair enzyme that initiates a base excision repair (BER by recognizing and removing 8-Oxoguanine (8-oxoG and its paired adenine. We demonstrated that both TGF-β1 and H2O2 treatment led to an increased 8-oxoG in cultured human proximal tubule epithelial (HK-2 cells, while the former induced epithelial-mesenchymal transition and the latter caused cell apoptosis. Without stimulation, HK-2 cells showed MUTYH expression in mitochondria. TGF-β1 triggered a transient upregulation of mitochondrial MUTYH and induced the expression of nuclear isoforms, while H2O2 showed no role on MUTYH expression. Ureteral obstruction (UUO mice exhibited high 8-oxoG reactivity with tubulointerstitial lesions. After obstruction, the MUTYH expression was increased only in tubules at day 3 and decreased with obvious tubular atrophy at day 10. Particularly, MUTYH was primarily located in normal tubular cytoplasm with a dominant mitochondrial form. A few cells with nuclear MUTYH expression were observed in the fibrotic interstitium. We confirmed that increased MUTYH expression was upregulated and positively correlated with the severity of kidney fibrosis. Thus, renal fibrosis caused a cell-type-specific and time-dependent response of oxidative DNA repairs, even within the same tissues. It suggests that intervention of MUTYH might be effective for therapies.

  17. Efficacy of Low Level Laser Therapy After Hand Flexor Tendon Repair

    Science.gov (United States)

    Ayad, K. E.; El Gohary, H. M.; Abd Elrahman, M.; Abd El Mejeed, S. F.; Bekheet, A. B.

    2009-09-01

    Flexor tendon injury is a common problem requiring suturing repair followed by early postoperative mobilization. Muscle atrophy, joint stiffness, osteoarthritis, infection, skin necrosis, ulceration of joint cartilage and tendocutaneous adhesion are familiar complications produced by prolonged immobilization of surgically repaired tendon ruptures. The purpose of this study was to clarify the importance of low level laser therapy after hand flexor tendon repair in zone II. Thirty patients aging between 20 and 40 years were divided into two groups. Patients in group A (n = 15) received a conventional therapeutic exercise program while patients in group B (n = 15) received low level laser therapy combined with the same therapeutic exercise program. The results showed a statistically significant increase in total active motion of the proximal and distal interphalangeal joints as well as maximum hand grip strength at three weeks and three months postoperative, but improvement was more significant in group B. It was concluded that the combination of low level laser therapy and early therapeutic exercises was more effective than therapeutic exercises alone in improving total active motion of proximal and distal interphalangeal joints and hand grip strength after hand flexor tendon repair.

  18. Efficacy of Low Level Laser Therapy After Hand Flexor Tendon Repair

    International Nuclear Information System (INIS)

    Flexor tendon injury is a common problem requiring suturing repair followed by early postoperative mobilization. Muscle atrophy, joint stiffness, osteoarthritis, infection, skin necrosis, ulceration of joint cartilage and tendocutaneous adhesion are familiar complications produced by prolonged immobilization of surgically repaired tendon ruptures. The purpose of this study was to clarify the importance of low level laser therapy after hand flexor tendon repair in zone II. Thirty patients aging between 20 and 40 years were divided into two groups. Patients in group A (n = 15) received a conventional therapeutic exercise program while patients in group B (n = 15) received low level laser therapy combined with the same therapeutic exercise program. The results showed a statistically significant increase in total active motion of the proximal and distal interphalangeal joints as well as maximum hand grip strength at three weeks and three months postoperative, but improvement was more significant in group B. It was concluded that the combination of low level laser therapy and early therapeutic exercises was more effective than therapeutic exercises alone in improving total active motion of proximal and distal interphalangeal joints and hand grip strength after hand flexor tendon repair.

  19. Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors.

    Science.gov (United States)

    Weingeist, David M; Ge, Jing; Wood, David K; Mutamba, James T; Huang, Qiuying; Rowland, Elizabeth A; Yaffe, Michael B; Floyd, Scott; Engelward, Bevin P

    2013-03-15

    A key modality of non-surgical cancer management is DNA damaging therapy that causes DNA double-strand breaks that are preferentially toxic to rapidly dividing cancer cells. Double-strand break repair capacity is recognized as an important mechanism in drug resistance and is therefore a potential target for adjuvant chemotherapy. Additionally, spontaneous and environmentally induced DSBs are known to promote cancer, making DSB evaluation important as a tool in epidemiology, clinical evaluation and in the development of novel pharmaceuticals. Currently available assays to detect double-strand breaks are limited in throughput and specificity and offer minimal information concerning the kinetics of repair. Here, we present the CometChip, a 96-well platform that enables assessment of double-strand break levels and repair capacity of multiple cell types and conditions in parallel and integrates with standard high-throughput screening and analysis technologies. We demonstrate the ability to detect multiple genetic deficiencies in double-strand break repair and evaluate a set of clinically relevant chemical inhibitors of one of the major double-strand break repair pathways, non-homologous end-joining. While other high-throughput repair assays measure residual damage or indirect markers of damage, the CometChip detects physical double-strand breaks, providing direct measurement of damage induction and repair capacity, which may be useful in developing and implementing treatment strategies with reduced side effects. PMID:23422001

  20. Gene Therapy In Squamous Cell Carcinoma – A Short Review

    Directory of Open Access Journals (Sweden)

    Soma Susan Varghese

    2011-07-01

    Full Text Available Oral cancer remains one of the leading causes of death world wide. Various means to destroy tumor cells preferentially have been developed; gene therapy is one among them with less treatment morbidity. Gene therapy involves the transfer of therapeutic or working copy of genes into a specific cell of an individual in order to repair a faulty copy of gene. The alteration can be accomplished by repairing or replacing the damaged DNA by various strategies and vectors. To date genetically altered viruses are commonly used as gene delivery vehicle (vector which has an advantage of evolutionary selection of host-virus relation. Non viral vectors which include the physical transfection of genes can be accomplished by electrophoration, microinjection, or use of ballistic particles and chemical transfection by forming liposomes.

  1. Mesenchymal Stem Cells: Application for Immunomodulation and Tissue Repair

    DEFF Research Database (Denmark)

    Horwood, Nicole J.; Dazzi, Francesco; Zaher, Walid; Kassem, Moustapha

    Mesenchymal stem cells (MSC) are stem cell populations present among the bone marrow stroma and a number of other tissues that are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. MSC provide supportive stroma for growth and...... differentiation of hematopoietic stem cells (HSC) and hematopoiesis. These cells have been described as important immunoregulators due to their ability to suppress T cells proliferation. MSC can also directly contribute to tissue repair by migrating to sites of injury and providing a source of cells for...... differentiation and/or providing bystander support for resident stromal cells. This chapter discusses the cellular and molecular properties of MSC, the mechanisms by which they can modulate immune responses and the clinical applications of MSC in disorders such as graft-versus-host disease and aplastic anaemia...

  2. Limbal Stem Cell Therapy

    OpenAIRE

    Kringlegarden, Hilde Grane

    2013-01-01

    It is widely accepted today that stem cells in the adult corneal epithelium is located to the limbus. No specific marker of limbal epithelial cells (LESCs) has been identified, yet many have been suggested, including ΔNp63α, ABCG2, vimentin and notch 1. Negative markers include amongst others the differentiation markers Ck3 and Ck12. The lack of an identified specific marker elucidates the need for establishment of more exact molecular markers of LESCs. Limbal stem cell deficiency (LSCD) may ...

  3. Regulation of DNA repair in serum-stimulated xeroderma pigmentosum cells

    OpenAIRE

    1984-01-01

    The regulation of DNA repair during serum stimulation of quiescent cells was examined in normal human cells, in fibroblasts from three xeroderma pigmentosum complementation groups (A, C, and D), in xeroderma pigmentosum variant cells, and in ataxia telangiectasia cells. The regulation of nucleotide excision repair was examined by exposing cells to ultraviolet irradiation at discrete intervals after cell stimulation. Similarly, base excision repair was quantitated after exposure to methylmetha...

  4. Mathematical modeling of the cells repair regulations in Nasopharyngeal carcinoma.

    Science.gov (United States)

    Adi-Kusumo, Fajar; Wiraya, Ario

    2016-07-01

    Nasopharyngeal Carcinoma (NPC) is a malignant cancer which is caused by the activation of Epstein-Barr Virus (EBV) via some external factors. In the cells repair regulations, the p53 gene mutation can be used as the early indication of the NPC growth. The NPC growth is due to the DNA damage accumulation caused by the EBV infection. In this paper we construct the cells repair regulations model to characterize the NPC growth. The model is a 15 dimensional of first order ODE system and consists the proteins and enzymes reactions. We do some numerical simulations to show the inactivation of the phosphorylated and acetylated p53, and the chromosomal instability of p53 gene, which can be used as the earlier stage detection of NPC. PMID:27140528

  5. Cell based therapies for ischemic stroke: From basic science to bedside

    OpenAIRE

    Liu, Xinfeng; Ye, Ruidong; Yan, Tao; Yu, Shan Ping; Wei, Ling; Xu, Gelin; Fan, Xinying; Jiang, Yongjun; Stetler, R. Anne; Liu, George; Chen, Jieli

    2013-01-01

    Cell therapy is emerging as a viable therapy to restore neurological function after stroke. Many types of stem/progenitor cells from different sources have been explored for their feasibility and efficacy for the treatment of stroke. Transplanted cells not only have the potential to replace the lost circuitry, but also produce growth and trophic factors, or stimulate the release of such factors from host brain cells, thereby enhancing endogenous brain repair processes. Although stem/progenito...

  6. Myelin repair and functional recovery mediated by neural cell transplantation in a mouse model of multiple sclerosis

    Institute of Scientific and Technical Information of China (English)

    Lianhua Bai; Jordan Hecker; Amber Kerstetter; Robert H.Miller

    2013-01-01

    Cellular therapies are becoming a major focus for the treatment of demyelinating diseases such as multiple sclerosis (MS),therefore it is important to identify the most effective cell types that promote myelin repair.Several components contribute to the relative benefits of specific cell types including the overall efficacy of the cell therapy,the reproducibility of treatment,the mechanisms of action of distinct cell types and the ease of isolation and generation of therapeutic populations.A range of distinct cell populations promote functional recovery in animal models of MS including neural stem cells and mesenchymal stem cells derived from different tissues.Each of these cell populations has advantages and disadvantages and likely works through distinct mechanisms.The relevance of such mechanisms to myelin repair in the adult central nervous system is unclear since the therapeutic cells are generally derived from developing animals.Here we describe the isolation and characterization of a population of neural cells from the adult spinal cord that are characterized by the expression of the cell surface glycoprotein NG2.In functional studies,injection of adult NG2+ cells into mice with ongoing MOG35-55-induced experimental autoimmune encephalomyelitis (EAE) enhanced remyelination in the CNS while the number of CD3+ T cells in areas of spinal cord demyelination was reduced approximately three-fold.In vivo studies indicated that in EAE,NG2+ cells stimulated endogenous repair while in vitro they responded to signals in areas of induced inflammation by differentiating into oligodendrocytes.These results suggested that adult NG2+ cells represent a useful cell population for promoting neural repair in a variety of different conditions including demyelinating diseases such as MS.

  7. Current Stem Cell Delivery Methods for Myocardial Repair

    OpenAIRE

    Sheng, Calvin C.; Li Zhou; Jijun Hao

    2013-01-01

    Heart failure commonly results from an irreparable damage due to cardiovascular diseases (CVDs), the leading cause of morbidity and mortality in the United States. In recent years, the rapid advancements in stem cell research have garnered much praise for paving the way to novel therapies in reversing myocardial injuries. Cell types currently investigated for cellular delivery include embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and adult stem cell lineages such as ske...

  8. Bone marrow cells - a tool for spinal cord injury repair

    Czech Academy of Sciences Publication Activity Database

    Syková, Eva; Urdzíková, Lucia; Jendelová, Pavla; Burian, M.; Glogarová, Kateřina; Hájek, M.

    Elsevier. Roč. 193, č. 1 (2005), s. 261-262. ISSN 0014-4886. [Annual Conference of the American Society for Neural Transplantation and Repair /12./. 28.04.2005-02.05.2005, Clearwater] R&D Projects: GA MŠk(CZ) LN00A065; GA ČR(CZ) GA304/03/1189 Institutional research plan: CEZ:AV0Z50390512 Keywords : bone marrow cells Subject RIV: FH - Neurology

  9. Fibroblast growth factor 2 and DNA repair involvement in the keratinocyte stem cells response to ionizing radiation

    International Nuclear Information System (INIS)

    Keratinocyte stem cells (KSCs) from the human inter follicular epidermis are regarded as the major target to radiation during radiotherapy. We found herein that KSCs are more resistant to ionizing radiation than their direct progeny, and presented more rapid DNA damage repair kinetics than the progenitors. Furthermore, we provided evidence describing the effect of fibroblast growth factor 2 (FGF2) signaling on the ability of KSCs and progenitors to repair damaged DNA. Despite our knowledge of the fact, that FGF is an anti-apoptotic factor in multiple cell types, the direct link between DNA repair and FGF2 signaling has rarely been shown. Existence of such link is an important issue with implications not only to stem cell field but also to cancer therapy. (author)

  10. Recent advances in cell-based therapy for Parkinson disease

    DEFF Research Database (Denmark)

    Astradsson, Arnar; Cooper, Oliver; Vinuela, Angel;

    2008-01-01

    In this review, the authors discuss recent advances in the field of cell therapy for Parkinson disease (PD). They compare and contrast recent clinical trials using fetal dopaminergic neurons. They attribute differences in cell preparation techniques, cell type specification, and immunosuppression...... progress in enrichment and purification strategies of stem cell-derived dopaminergic midbrain neurons. They conclude that recent advances in cell therapy for PD will create a viable long-term treatment option for synaptic repair for this debilitating disease....... as reasons for variable outcome and for some of the side effects observed in these clinical trials. To address ethical, practical, and technical issues related to the use of fetal cell sources, alternative sources of therapeutic dopaminergic neurons are being developed. The authors describe the...

  11. Advances in corneal cell therapy.

    Science.gov (United States)

    Fuest, Matthias; Yam, Gary Hin-Fai; Peh, Gary Swee-Lim; Mehta, Jodhbir S

    2016-09-01

    Corneal integrity is essential for visual function. Transplantation remains the most common treatment option for advanced corneal diseases. A global donor material shortage requires a search for alternative treatments. Different stem cell populations have been induced to express corneal cell characteristics in vitro and in animal models. Yet before their application to humans, scientific and ethical issues need to be solved. The in vitro propagation and implantation of primary corneal cells has been rapidly evolving with clinical practices of limbal epithelium transplantation and a clinical trial for endothelial cells in progress, implying cultivated ocular cells as a promising option for the future. This review reports on the latest developments in primary ocular cell and stem cell research for corneal therapy. PMID:27498943

  12. Towards personalized regenerative cell therapy

    DEFF Research Database (Denmark)

    Lin, Lin; Bolund, Lars; Luo, Yonglun

    2015-01-01

    Mesenchymal stem cells (MSCs) are adult stem cells with the capacity of self-renewal and multilineage differentiation, and can be isolated from several adult tissues. However, isolating MSCs from adult tissues for cell therapy is hampered by the invasive procedure, the rarity of the cells and their...... attenuated proliferation capacity when cultivated and expanded in vitro. Human MSCs derived from induced pluripotent stem cells (iPSC-MSCs) have now evolved as a promising alternative cell source for MSCs and regenerative medicine. Several groups, including ours, have reported successful derivation of...... functional iPSC-MSCs and applied these cells in MSC-based therapeutic testing. Still, the current experience and understanding of iPSC-MSCs with respect to production methods, safety and efficacy are primitive. In this review, we highlight the methodological progress in iPSC-MSC research, describing the...

  13. DNA repair in a Fanconi's anemia fibroblast cell strain

    International Nuclear Information System (INIS)

    DNA repair and colony survival were measured in fibroblasts from a patient with Fanconi's anemia, HG 261, and from normal human donors after exposure to these cells to the cross-linking agent mitomycin C, X-rays or ultraviolet light. Survival was similar in HG 261 and normal cells after X-ray or ultraviolet radiation, but was reduced in the Fanconi's anemia cells after treatment with mitomycin C. The level of DNA cross-linking, as measured by the method of alkaline elution, was the same in both cell strains after exposure to various doses of mitomycin C. With incubation after drug treatment, a gradual decrease in the amount of cross-linking was observed, the rate of this apparent repair of cross-link damage was the same in both normal and HG 261 cells. The rejoining of DNA single strand breaks after X-irradiation and the production of excision breaks after ultraviolet radiation were also normal in HG 261 cells as determined by alkaline elution. (Auth.)

  14. Early sensory re-education of the hand after peripheral nerve repair based on mirror therapy: a randomized controlled trial

    OpenAIRE

    Paula, Mayara H.; Barbosa, Rafael I.; Marcolino, Alexandre M; Valéria M.C. Elui; Birgitta Rosén; Marisa C. R. Fonseca

    2016-01-01

    BACKGROUND: Mirror therapy has been used as an alternative stimulus to feed the somatosensory cortex in an attempt to preserve hand cortical representation with better functional results. OBJECTIVE: To analyze the short-term functional outcome of an early re-education program using mirror therapy compared to a late classic sensory program for hand nerve repair. METHOD: This is a randomized controlled trial. We assessed 20 patients with median and ulnar nerve and flexor tendon repair usin...

  15. Early sensory re-education of the hand after peripheral nerve repair based on mirror therapy: a randomized controlled trial

    OpenAIRE

    Paula, Mayara H.; Barbosa, Rafael I.; Marcolino, Alexandre M; Valéria M.C. Elui; Rosén, Birgitta; Marisa C. R. Fonseca

    2016-01-01

    BACKGROUND: Mirror therapy has been used as an alternative stimulus to feed the somatosensory cortex in an attempt to preserve hand cortical representation with better functional results. OBJECTIVE: To analyze the short-term functional outcome of an early re-education program using mirror therapy compared to a late classic sensory program for hand nerve repair. METHOD: This is a randomized controlled trial. We assessed 20 patients with median and ulnar nerve and flexor tendon repair using the...

  16. Current Status of Cell Therapies in Stroke

    OpenAIRE

    Bang, Oh Young

    2009-01-01

    Stroke is a leading cause of death and disability in adults. Recovery after stroke is usually limited as there is no definite therapy to restore lost brain function. Cell therapy is an emerging paradigm in stroke therapy for patients with fixed neurologic deficits. Cell therapy for stroke may be greatly different from cell therapy for other disease conditions; the complexity of central nervous system structures and functions may limit its effectiveness. Recently, there have been several clini...

  17. Non-DBS DNA Repair Genes Regulate Radiation-induced Cytogenetic Damage Repair and Cell Cycle Progression

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Casey, Rachael; Wu, Honglu

    2008-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in DSB repair, and its impact on cytogenetic responses has not been systematically studied. In the present study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by transfection with small interfering RNA in human fibroblast cells. The purpose of this study is to identify new roles of these selected genes on regulating DSB repair and cell cycle progression , as measured in the micronuclei formation and chromosome aberration. In response to IR, the formation of MN was significantly increased by suppressed expression of 5 genes: Ku70 in the DSB repair pathway, XPA in the NER pathway, RPA1 in the MMR pathway, and RAD17 and RBBP8 in cell cycle control. Knocked-down expression of 4 genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Furthermore, loss of XPA, P21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Most of the 11 genes that affected cytogenetic responses are not known to have clear roles influencing DBS repair. Nine of these 11 genes were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate the biological consequences after IR.

  18. Scintillometric determination of DNA repair in human cell lines

    International Nuclear Information System (INIS)

    The ability of a variety of chemical and physical agents to stimulate DNA repair synthesis in human cell cultures was tested by a simplified scintillometric procedure, with the use of hydroxyurea (HU) to suppress DNA replicative synthesis. After incubation with [3H]thymidine, the radioactivity incorporated into DNA was determined in controls (C) and treated (T) cultures and in the corresponding HU series (Csub(HU), Tsub(HU)). The ratios Tsub(HU)/Csub(HU) and Tsub(HU)/T:Csub(HU)/C, indicating absolute and relative increases of DNA radioactivity, were calculated. When both ratios were significantly higher than 1, they were taken as indices of DNA repair stimulation. (orig./AJ)

  19. Stem cells for liver tissue repair:Current knowledge and perspectives

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Stem cells from extra- or intrahepatic sources have been recently characterized and their usefulness for the generation of hepatocyte-like lineages has been demonstrated.Therefore,they are being increasingly considered for future applications in liver cell therapy.In that field,liver cell transplantation is currently regarded as a possible alternative to whole organ transplantation,while stem cells possess theoretical advantages on hepatocytes as they display higher in vitro culture performances and could be used in autologous transplant procedures.However,the current research on the hepatic fate of stem cells is still facing difficulties to demonstrate the acquisition of a full mature hepatocyte phenotype,both in vitro and in vivo.Furthermore,the lack of obvious demonstration of in vivo hepatocyte-like cell functionality remains associated to low repopulation rates obtained after current transplantation procedures.The present review focuses on the current knowledge of the stern cell potential for liver therapy.We discuss the characteristics of the principal cell candidates and the methods to demonstrate their hepatic potential in vitro and in vivo.We finally address the question of the future clinical applications of stem cells for liver tissue repair and the technical aspects that remain to be investigated.

  20. FGF2 mediates DNA repair in epidermoid carcinoma cells exposed to ionizing radiation

    International Nuclear Information System (INIS)

    Fibroblast growth factor 2 (FGF2) is a well-known survival factor. However, its role in DNA repair is poorly documented. The present study was designed to investigate in epidermoid carcinoma cells the potential role of FGF2 in DNA repair. The side population (SP) with cancer stem cell-like properties and the main population (MP) were isolated from human A431 squamous carcinoma cells. Radiation-induced DNA damage and repair were assessed using the alkaline comet assay. FGF2 expression was quantified by enzyme linked immunosorbent assay (ELISA). SP cells exhibited rapid repair of radiation induced DNA damage and a high constitutive level of nuclear FGF2. Blocking FGF2 signaling abrogated the rapid DNA repair. In contrast, in MP cells, a slower repair of damage was associated with low basal expression of FGF2. Moreover, the addition of exogenous FGF2 accelerated DNA repair in MP cells. When irradiated, SP cells secreted FGF2, whereas MP cells did not. FGF2 was found to mediate DNA repair in epidermoid carcinoma cells. We postulate that carcinoma stem cells would be intrinsically primed to rapidly repair DNA damage by a high constitutive level of nuclear FGF2. In contrast, the main population with a low FGF2 content exhibits a lower repair rate which can be increased by exogenous FGF2. (authors)

  1. Control of radiation sensitivity of mammalian cells. Regulation of expression of DNA repair genes

    International Nuclear Information System (INIS)

    This review describes authors' investigations concerning regulation of expression of DNA repair genes for the purpose of control of radiosensitivity of mammalian cells for cancer radiotherapy. One of their experiments concerns the enhancement of sensitivity to radiation and anti-tumor agents by suppressing the expression of mammalian Rad51 gene which playing a central role in recombination repair against DNA double-strand break, by RNA interference (RNAi). Described are the mode of action of RNAi, mechanism of suppression of Rad51 gene expression by it, enhancing effect in radiosensitivity, stable suppression and enhancement by hairpin RNA and its possible usefulness in cancer therapy. The other concerns the histone H2AX gene, which delivering the repair signal post phosphorylation in chromatin against the double-strand break. Experimental results of suppression of the histone H2AX gene by tet-off system, enhancement of radiosensitivity by the suppression and functional recovery by the gene transfer are described, and the radiosensitivity can be thus artificially controlled by tetracycline in authors' F9 2AX (tet/tet) cells. (N.I.)

  2. Cell therapy in congestive heart failure

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Congestive heart failure (CHF) has emerged as a major worldwide epidemic and its main causes seem to be the aging of the population and the survival of patients with post-myocardial infarction. Cardiomyocyte dropout (necrosis and apoptosis) plays a critical role in the progress of CHF; thus treatment of CHF by exogenous cell implantation will be a promising medical approach. In the acute phase of cardiac damage cardiac stem cells (CSCs) within the heart divide symmetrically and/or asymmetrically in response to the change of heart homeostasis, and at the same time homing of bone marrow stem cells (BMCs) to injured area is thought to occur, which not only reconstitutes CSC population to normal levels but also repairs the heart by differentiation into cardiac tissue. So far, basic studies by using potential sources such as BMCs and CSCs to treat animal CHF have shown improved ventricular remodelling and heart function. Recently, however, a few of randomized, double-blind, placebo-controlled clinical trials demonstrated mixed results in heart failure with BMC therapy during acute myocardial infarction.

  3. Adult Stem Cells and Diabetes Therapy

    OpenAIRE

    Ilgun, Handenur; Kim, Joseph William; Luo, LuGuang

    2015-01-01

    The World Health Organization estimates that diabetes will be the fourth most prevalent disease by 2050. Developing a new therapy for diabetes is a challenge for researchers and clinicians in field. Many medications are being used for treatment of diabetes however with no conclusive and effective results therefore alternative therapies are required. Stem cell therapy is a promising tool for diabetes therapy, and it has involved embryonic stem cells, adult stem cells, and pluripotent stem cell...

  4. Stem cell therapy in the management of shoulder rotatorcuff disorders

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Rotator cuff tears are frequent shoulder problems thatare usually dealt with surgical repair. Despite improvedsurgical techniques, the tendon-to-bone healing rateis unsatisfactory due to difficulties in restoring thedelicate transitional tissue between bone and tendon.It is essential to understand the molecular mechanismsthat determine this failure. The study of the molecularenvironment during embryogenesis and during normalhealing after injury is key in devising strategies to geta successful repair. Mesenchymal stem cells (MSC) candifferentiate into different mesodermal tissues and havea strong paracrine, anti-inflammatory, immunoregulatoryand angiogenic potential. Stem cell therapy is thus apotentially effective therapy to enhance rotator cuffhealing. Promising results have been reported with theuse of autologous MSC of different origins in animalstudies they have shown to have better healing properties,increasing the amount of fibrocartilage formationand improving the orientation of fibrocartilage fibers withless immunologic response and reduced lymphocyteinfiltration. All these changes lead to an increase inbiomechanical strength. However, animal research is stillinconclusive and more experimental studies are neededbefore human application. Future directions includeexpanded stem cell therapy in combination with growthfactors or different scaffolds as well as new stem celltypes and gene therapy.

  5. Low-level laser therapy (LLLT) reduces inflammatory infiltrate and enhances skeletal muscle repair: Histomorphometric parameters

    Science.gov (United States)

    Paiva-Oliveira, E. L.; Lima, N. C.; Silva, P. H.; Sousa, N. T. A.; Barbosa, F. S.; Orsini, M.; Silva, J. G.

    2012-09-01

    Low level laser therapy (LLLT) has been suggested as an effective therapeutics in inflammatory processes modulation and tissue repairing. However, there is a lack of studies that analyze the anti-inflammatory effects of the infrared lasers in muscular skeletal injury. The aim of this study was to investigate the effects of low-level laser therapy 904 nm in the repair process of skeletal muscle tissue. Swiss mice were submitted to cryoinjury and divided in test (LLLT-treated) and control groups. Histological sections were stained with hematoxylin-eosin to assess general morphology and inflammatory influx, and Picrossirus to quantify collagen fibers deposition. Our results showed significant reduction in inflammatory infiltrated in irradiated mice after 4 days of treatment compared to control ( p = 0.01). After 8 days, the irradiated group showed high levels at regenerating myofibers with significant statistically differences in relation at control group ( p LLLT reduces the inflammatory response in the initial stages of injury and accelerates the process of muscular tissue repair.

  6. Moving from the laboratory bench to patients' bedside: considerations for effective therapy with stem cells.

    Science.gov (United States)

    Sherman, Lauren S; Munoz, Jessian; Patel, Shyam A; Dave, Meneka A; Paige, Ilani; Rameshwar, Pranela

    2011-10-01

    Although stem cell therapy is not a new field, the field was limited to transplantation of hematopoietic stem cells. Such transplantation has provided invaluable information for the emerging field with new stem cells. Mesenchymal stem cells (MSCs) are an attractive source for therapy; reduced ethical concern, ease in expansion, as off-the-shelf stem cells. MSCs exert immune suppressive properties, providing them with the potential for immune suppressive therapy such as autoimmunity, asthma, allergic rhinitis and graft versus host disease. In addition, MSCs, as well as other stem cells, can be applied for bone and cartilage repair, cardiovascular disease, and neural repair/protection. The data thus far with MSCs are mixed. This review discusses the immune-enhancing properties of MSCs to explain the possible confounds of inflammatory microenvironment in the MSCs therapy. Although this review focuses on MSCs, the information can be extrapolated to other stem cells. The review summarizes the biology of MSCs, including multilineage differentiation potential, transdifferentiation capability, and immunological effects. We emphasize the key concepts that may predict the use of these cells in medicine, namely, the application of these cells from the bench to the bedside. Prospects on immunotherapy, neuroregeneration, and cardiovascular repair are used as examples of tissue repair. PMID:22029813

  7. Mesenchymal stem cell therapy and lung diseases.

    Science.gov (United States)

    Akram, Khondoker M; Samad, Sohel; Spiteri, Monica; Forsyth, Nicholas R

    2013-01-01

    Mesenchymal stem cells (MSCs), a distinct population of adult stem cells, have amassed significant interest from both medical and scientific communities. An inherent multipotent differentiation potential offers a cell therapy option for various diseases, including those of the musculoskeletal, neuronal, cardiovascular and pulmonary systems. MSCs also secrete an array of paracrine factors implicated in the mitigation of pathological conditions through anti-inflammatory, anti-apoptotic and immunomodulatory mechanisms. The safety and efficacy of MSCs in human application have been confirmed through small- and large-scale clinical trials. However, achieving the optimal clinical benefit from MSC-mediated regenerative therapy approaches is entirely dependent upon adequate understanding of their healing/regeneration mechanisms and selection of appropriate clinical conditions. MSC-mediated acute alveolar injury repair. A cartoon depiction of an injured alveolus with associated inflammation and AEC apoptosis. Proposed routes of MSC delivery into injured alveoli could be by either intratracheal or intravenous routes, for instance. Following delivery a proposed mechanism of MSC action is to inhibit/reduce alveolar inflammation by abrogation of IL-1_-depenedent Tlymphocyte proliferation and suppression of TNF-_ secretion via macrophage activation following on from stimulation by MSC-secreted IL-1 receptor antagonist (IL-1RN). The inflammatory environment also stimulates MSC to secrete prostaglandin-E2 (PGE2) which can stimulate activated macrophages to secrete the anti-inflammatory cytokine IL-10. Inhibition of AEC apoptosis following injury can also be promoted via MSC stimulated up-regulation of the anti-apoptotic Bcl-2 gene. MSC-secreted KGF can stimulate AECII proliferation and migration propagating alveolar epithelial restitution. Alveolar structural engraftment of MSC is a rare event. PMID:22772131

  8. Dystrophin Gene Replacement and Gene Repair Therapy for Duchenne Muscular Dystrophy in 2016: An Interview.

    Science.gov (United States)

    Duan, Dongsheng

    2016-03-01

    After years of relentless efforts, gene therapy has now begun to deliver its therapeutic promise in several diseases. A number of gene therapy products have received regulatory approval in Europe and Asia. Duchenne muscular dystrophy (DMD) is an X-linked inherited lethal muscle disease. It is caused by mutations in the dystrophin gene. Replacing and/or repairing the mutated dystrophin gene holds great promises to treated DMD at the genetic level. Last several years have evidenced significant developments in preclinical experimentations in murine and canine models of DMD. There has been a strong interest in moving these promising findings to clinical trials. In light of rapid progress in this field, the Parent Project Muscular Dystrophy (PPMD) recently interviewed me on the current status of DMD gene therapy and readiness for clinical trials. Here I summarized the interview with PPMD. PMID:27003751

  9. Effect of adipose-derived stromal cells and BMP12 on intrasynovial tendon repair: A biomechanical, biochemical, and proteomics study.

    Science.gov (United States)

    Gelberman, Richard H; Shen, Hua; Kormpakis, Ioannis; Rothrauff, Benjamin; Yang, Guang; Tuan, Rocky S; Xia, Younan; Sakiyama-Elbert, Shelly; Silva, Matthew J; Thomopoulos, Stavros

    2016-04-01

    The outcomes of flexor tendon repair are highly variable. As recent efforts to improve healing have demonstrated promise for growth factor- and cell-based therapies, the objective of the current study was to enhance repair via application of autologous adipose derived stromal cells (ASCs) and the tenogenic growth factor bone morphogenetic protein (BMP) 12. Controlled delivery of cells and growth factor was achieved in a clinically relevant canine model using a nanofiber/fibrin-based scaffold. Control groups consisted of repair-only (no scaffold) and acellular scaffold. Repairs were evaluated after 28 days of healing using biomechanical, biochemical, and proteomics analyses. Range of motion was reduced in the groups that received scaffolds compared to normal. There was no effect of ASC + BMP12 treatment for range of motion or tensile properties outcomes versus repair-only. Biochemical assays demonstrated increased DNA, glycosaminoglycans, and crosslink concentration in all repair groups compared to normal, but no effect of ASC + BMP12. Total collagen was significantly decreased in the acellular scaffold group compared to normal and significantly increased in the ASC + BMP12 group compared to the acellular scaffold group. Proteomics analysis comparing healing tendons to uninjured tendons revealed significant increases in proteins associated with inflammation, stress response, and matrix degradation. Treatment with ASC + BMP12 amplified these unfavorable changes. In summary, the treatment approach used in this study induced a negative inflammatory reaction at the repair site leading to poor healing. Future approaches should consider cell and growth factor delivery methods that do not incite negative local reactions. PMID:26445383

  10. Plastic Fantastic: Schwann Cells and Repair of the Peripheral Nervous System

    OpenAIRE

    Kim, Haesun A.; Mindos, Thomas; Parkinson, David B.

    2013-01-01

    Repair in the peripheral nervous system (PNS) is a complex process that requires the active de-differentiation of Schwann cells to an immature repair state following injury; this de-differentiation is dependent upon the activity of the p38 and ERK1/2 mitogen-activated protein kinases, as well as the transcription factor cJun. Understanding the mechanisms of repair raises the possibility of both boosting repair after PNS trauma and even, possibly, blocking the inappropriate demyelination seen ...

  11. Human periodontal ligament stem cells repair mental nerve injury*

    Institute of Scientific and Technical Information of China (English)

    Bohan Li; Hun-Jong Jung; Soung-Min Kim; Myung-Jin Kim; Jeong Won Jahng; Jong-Ho Lee

    2013-01-01

    Human periodontal ligament stem cells are easily accessible and can differentiate into Schwann cells. We hypothesized that human periodontal ligament stem cells can be used as an alternative source for the autologous Schwann cells in promoting the regeneration of injured peripheral nerve. To validate this hypothesis, human periodontal ligament stem cells (1 × 106) were injected into the crush-injured left mental nerve in rats. Simultaneously, autologous Schwann cells (1 × 106) and PBS were also injected as controls. Real-time reverse transcriptase polymerase chain reaction showed that at 5 days after injection, mRNA expression of low affinity nerve growth factor receptor was sig-nificantaly increased in the left trigeminal ganglion of rats with mental nerve injury. Sensory tests, histomorphometric evaluation and retrograde labeling demonstrated that at 2 and 4 weeks after in-jection, sensory function was significantly improved, the numbers of retrograde labeled sensory neurons and myelinated axons were significantly increased, and human periodontal ligament stem cells and autologous Schwann cells exhibited similar therapeutic effects. These findings suggest that transplantation of human periodontal ligament stem cells show a potential value in repair of mental nerve injury.

  12. Stem cells: sources and therapies.

    Science.gov (United States)

    Monti, Manuela; Perotti, Cesare; Del Fante, Claudia; Cervio, Marila; Redi, Carlo Alberto

    2012-01-01

    The historical, lexical and conceptual issues embedded in stem cell biology are reviewed from technical, ethical, philosophical, judicial, clinical, economic and biopolitical perspectives. The mechanisms assigning the simultaneous capacity to self-renew and to differentiate to stem cells (immortal template DNA and asymmetric division) are evaluated in the light of the niche hypothesis for the stemness state. The induction of cell pluripotency and the different stem cells sources are presented (embryonic, adult and cord blood). We highlight the embryonic and adult stem cell properties and possible therapies while we emphasize the particular scientific and social values of cord blood donation to set up cord blood banks. The current scientific and legal frameworks of cord blood banks are reviewed at an international level as well as allogenic, dedicated and autologous donations. The expectations and the challenges in relation to present-day targeted diseases like diabetes mellitus type I, Parkinson's disease and myocardial infarction are evaluated in the light of the cellular therapies for regenerative medicine. PMID:23283430

  13. Repair of pyrimidine dimer ultraviolet light photoproducts by human cell extracts

    International Nuclear Information System (INIS)

    A newly developed method allows human cell extracts to carry out repair synthesis on ultraviolet light irradiated closed circular plasmid DNA. The identity of the photodamage that leads to this repair replication was investigated. Removal of stable pyrimidine hydrates from irradiated plasmid pAT153 did not significantly affect the amount of repair replication in the fluence range of 0-450 J/m2, because of the low yield of these products and their short DNA repair patch size. Photoreactivation of irradiated DNA using purified Escherichia coli DNA photolyase to remove more than 95% of the cyclobutane dimers from the DNA reduced the observed repair synthesis by 20-40%. The greater part of the repair synthesis is highly likely to be caused by (6-4) pyrimidine dimer photoproducts. This class of lesions is rapidly repaired by mammalian cells, and their removal is known to be important for cell survival after ultraviolet irradiation

  14. Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors

    OpenAIRE

    Weingeist, David M.; Ge, Jing; Wood, David K.; Mutamba, James T; Huang, Qiuying; Rowland, Elizabeth A.; Yaffe, Michael B.; Floyd, Scott; Engelward, Bevin P.

    2013-01-01

    A key modality of non-surgical cancer management is DNA damaging therapy that causes DNA double-strand breaks that are preferentially toxic to rapidly dividing cancer cells. Double-strand break repair capacity is recognized as an important mechanism in drug resistance and is therefore a potential target for adjuvant chemotherapy. Additionally, spontaneous and environmentally induced DSBs are known to promote cancer, making DSB evaluation important as a tool in epidemiology, clinical evaluatio...

  15. Current stem cell delivery methods for myocardial repair.

    Science.gov (United States)

    Sheng, Calvin C; Zhou, Li; Hao, Jijun

    2013-01-01

    Heart failure commonly results from an irreparable damage due to cardiovascular diseases (CVDs), the leading cause of morbidity and mortality in the United States. In recent years, the rapid advancements in stem cell research have garnered much praise for paving the way to novel therapies in reversing myocardial injuries. Cell types currently investigated for cellular delivery include embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and adult stem cell lineages such as skeletal myoblasts, bone-marrow-derived stem cells (BMSCs), mesenchymal stem cells (MSCs), and cardiac stem cells (CSCs). To engraft these cells into patients' damaged myocardium, a variety of approaches (intramyocardial, transendocardial, transcoronary, venous, intravenous, intracoronary artery and retrograde venous administrations and bioengineered tissue transplantation) have been developed and explored. In this paper, we will discuss the pros and cons of these delivery modalities, the current state of their therapeutic potentials, and a multifaceted evaluation of their reported clinical feasibility, safety, and efficacy. While the issues of optimal delivery approach, the best progenitor stem cell type, the most effective dose, and timing of administration remain to be addressed, we are highly optimistic that stem cell therapy will provide a clinically viable option for myocardial regeneration. PMID:23509740

  16. Current Stem Cell Delivery Methods for Myocardial Repair

    Directory of Open Access Journals (Sweden)

    Calvin C. Sheng

    2013-01-01

    Full Text Available Heart failure commonly results from an irreparable damage due to cardiovascular diseases (CVDs, the leading cause of morbidity and mortality in the United States. In recent years, the rapid advancements in stem cell research have garnered much praise for paving the way to novel therapies in reversing myocardial injuries. Cell types currently investigated for cellular delivery include embryonic stem cells (ESCs, induced pluripotent stem cells (iPSCs, and adult stem cell lineages such as skeletal myoblasts, bone-marrow-derived stem cells (BMSCs, mesenchymal stem cells (MSCs, and cardiac stem cells (CSCs. To engraft these cells into patients’ damaged myocardium, a variety of approaches (intramyocardial, transendocardial, transcoronary, venous, intravenous, intracoronary artery and retrograde venous administrations and bioengineered tissue transplantation have been developed and explored. In this paper, we will discuss the pros and cons of these delivery modalities, the current state of their therapeutic potentials, and a multifaceted evaluation of their reported clinical feasibility, safety, and efficacy. While the issues of optimal delivery approach, the best progenitor stem cell type, the most effective dose, and timing of administration remain to be addressed, we are highly optimistic that stem cell therapy will provide a clinically viable option for myocardial regeneration.

  17. Carotid Repair Using Autologous Adipose-Derived Endothelial Cells

    Science.gov (United States)

    Froehlich, Harald; Gulati, Rajiv; Boilson, Barry; Witt, Tyra; Harbuzariu, Adriana; Kleppe, Laurel; Dietz, Allan B.; Lerman, Amir; Simari, Robert D.

    2009-01-01

    Background and Purpose Adipose tissue is an abundant source of endothelial cells as well as stem and progenitor cells which can develop an endothelial phenotype. It has been demonstrated that these cells have distinct angiogenic properties in vitro and in vivo. However, whether these cells have the capacity to directly improve large vessel form and function following vascular injury remains unknown. To define whether delivery of adipose-derived endothelial cells (ADECs) would improve healing of injured carotid arteries, a rabbit model of acute arterial injury was employed. Methods Autologous rabbit ADECS were generated utilizing defined culture conditions. To test the ability of ADECs to enhance carotid artery repair, cells were delivered intra-arterially following acute balloon injury. Additional delivery studies were performed following functional selection of cells prior to delivery. Results Following rabbit omental fat harvest and digestion, a proliferative, homogenous, and distinctly endothelial population of ADECs was identified. Direct delivery of autologous ADECs resulted in marked re-endothelialization 48 hours following acute vascular injury as compared to saline controls (82.2 ±26.9% vs 4.2±3.0% pADECs that were selected for their ability to take up acetylated LDL significantly improved vasoreactivity and decreased intimal formation following vascular injury. Conclusions Taken together, these data suggest that ADECs represent an autologous source of proliferative endothelial cells which demonstrate the capacity to rapidly improve re-endothelialization, improve vascular reactivity, and decrease intimal formation in a carotid artery injury model. PMID:19286583

  18. The endoperoxide ascaridol shows strong differential cytotoxicity in nucleotide excision repair-deficient cells

    International Nuclear Information System (INIS)

    Targeting synthetic lethality in DNA repair pathways has become a promising anti-cancer strategy. However little is known about such interactions with regard to the nucleotide excision repair (NER) pathway. Therefore, cell lines with a defect in the NER genes ERCC6 or XPC and their normal counterparts were screened with 53 chemically defined phytochemicals isolated from plants used in traditional Chinese medicine for differential cytotoxic effects. The screening revealed 12 drugs that killed NER-deficient cells more efficiently than proficient cells. Five drugs were further analyzed for IC50 values, effects on cell cycle distribution, and induction of DNA damage. Ascaridol was the most effective compound with a difference of > 1000-fold in resistance between normal and NER-deficient cells (IC50 values for cells with deficiency in ERCC6: 0.15 μM, XPC: 0.18 μM, and normal cells: > 180 μM). NER-deficiency combined with ascaridol treatment led to G2/M-phase arrest, an increased percentage of subG1 cells, and a substantially higher DNA damage induction. These results were confirmed in a second set of NER-deficient and -proficient cell lines with isogenic background. Finally, ascaridol was characterized for its ability to generate oxidative DNA damage. The drug led to a dose-dependent increase in intracellular levels of reactive oxygen species at cytotoxic concentrations, but only NER-deficient cells showed a strongly induced amount of 8-oxodG sites. In summary, ascaridol is a cytotoxic and DNA-damaging compound which generates intracellular reactive oxidative intermediates and which selectively affects NER-deficient cells. This could provide a new therapeutic option to treat cancer cells with mutations in NER genes. -- Highlights: ► Thousand-fold higher Ascaridol activity in NER-deficient versus proficient cells. ► Impaired repair of Ascaridol-induced oxidative DNA damage in NER-deficient cells. ► Selective activity of Ascaridol opens new therapy options in NER

  19. The Fanconi anemia pathway: Repairing the link between DNA damage and squamous cell carcinoma

    International Nuclear Information System (INIS)

    Fanconi anemia (FA) is a rare inherited recessive disease caused by mutations in one of fifteen genes known to encode FA pathway components. In response to DNA damage, nuclear FA proteins associate into high molecular weight complexes through a cascade of post-translational modifications and physical interactions, followed by the repair of damaged DNA. Hematopoietic cells are particularly sensitive to the loss of these interactions, and bone marrow failure occurs almost universally in FA patients. FA as a disease is further characterized by cancer susceptibility, which highlights the importance of the FA pathway in tumor suppression, and will be the focus of this review. Acute myeloid leukemia is the most common cancer type, often subsequent to bone marrow failure. However, FA patients are also at an extreme risk of squamous cell carcinoma (SCC) of the head and neck and gynecological tract, with an even greater incidence in those individuals who have received a bone marrow transplant and recovered from hematopoietic disease. FA tumor suppression in hematopoietic versus epithelial compartments could be mechanistically similar or distinct. Definition of compartment specific FA activities is now critical to assess the effects of today's bone marrow failure treatments on tomorrow's solid tumor development. It is our hope that current therapies can then be optimized to decrease the risk of malignant transformation in both hematopoietic and epithelial cells. Here we review our current understanding of the mechanisms of action of the Fanconi anemia pathway as it contributes to stress responses, DNA repair and squamous cell carcinoma susceptibility

  20. Cell therapy in femur fractures

    International Nuclear Information System (INIS)

    Regenerative medicine has opened another opportunity for effective consolidation and rapid recovery of patients with traumatic injuries. We present a 46 year-old white male patient with a history of traffic accident. A middle third left femur fracture was diagnosed and plain radiographs showed IV grade comminution. He was released after 20 days of hospitalization with persistent pain despite of pain medication every 4-6 hours. Cell therapy was prescribed and it was performed on outpatient basis. After 48 hours the improvement was increased progressively, stability was achieved and pain disappeared in the fracture site, this was a symptom present since the accident. 8 weeks after cell therapy, radiological improvement was observed. In general, his evolution was considered satisfactory for the fast recovery and its incorporation into social life. This is the first patient in Artemisa province who underwent this new type of therapy and as far as we know at the time of this writing, it is also the first reported in the scientific literature in Cuba

  1. Peripheral Blood Mononuclear Cells Enhance Cartilage Repair in in vivo Osteochondral Defect Model.

    Science.gov (United States)

    Hopper, Niina; Wardale, John; Brooks, Roger; Power, Jonathan; Rushton, Neil; Henson, Frances

    2015-01-01

    This study characterized peripheral blood mononuclear cells (PBMC) in terms of their potential in cartilage repair and investigated their ability to improve the healing in a pre-clinical large animal model. Human PBMCs were isolated with gradient centrifugation and adherent PBMC's were evaluated for their ability to differentiate into adipogenic, chondrogenic and osteogenic lineages and also for their expression of musculoskeletal genes. The phenotype of the PBMCs was evaluated using Stro-1, CD34, CD44, CD45, CD90, CD106, CD105, CD146 and CD166 cell surface markers. Osteochondral defects were created in the medial femoral condyle (MFC) of 24 Welsh mountain sheep and evaluated at a six month time point. Four cell treatment groups were evaluated in combination with collagen-GAG-scaffold: (1) MSC alone; (2) MSCs and PBMCs at a ratio of 20:1; (3) MSCs and PBMC at a ratio of 2:1 and (4) PBMCs alone. Samples from the surgical site were evaluated for mechanical properties, ICRS score and histological repair. Fresh PBMC samples were 90% positive for hematopoietic cell surface markers and negative for the MSC antibody panel (stem cell markers in hypoxic culture and lacked CD34/45 positive cells (cells had acquired an MSC-like phenotype and transformed in hypoxia from their original hematopoietic lineage. Four key genes in muskuloskeletal biology were significantly upregulated in adherent PBMCs by hypoxia: BMP2 4.2-fold (p = 0.0007), BMP6 10.7-fold (p = 0.0004), GDF5 2.0-fold (p = 0.002) and COL1 5.0-fold (p = 0.046). The monolayer multilineage analysis confirmed the trilineage mesenchymal potential of the adherent PBMCs. PBMC cell therapy was equally good as bone marrow MSC therapy for defects in the ovine large animal model. Our results show that PBMCs support cartilage healing and oxygen tension of the environment was found to have a key effect on the derivation of a novel adherent cell population with an MSC-like phenotype. This study presents a novel and easily

  2. DNA repair in mammalian cells exposed to combinations of carcinogenic agents

    International Nuclear Information System (INIS)

    Cells defective in one or more aspects of repair are killed and often mutagenized more readily than normal cells by DNA damaging agents, and humans whose cells are deficient in repair are at an increased carcinogenic risk compared to normal individuals. The excision repair of uv induced pyrimidine dimers is a well studied system, but the details of the steps in this repair system are far from being understood in human cells. We know that there are a number of chemicals that mimic uv in that normal human cells repair DNA damage from both these agents and from uv by a long patch excision repair system, and that xeroderma pigmentosum cells defective in repair of uv are also defective in the repair of damage from these chemicals. The chemicals we have investigated are AAAF, 4-NQO, DMBA-epoxide, and ICR-170. We describe experiments, using several techniques, in which DNA excision repair is measured after treatment of various human cell strains with combinations of uv and these agents. If two agents have a common rate limiting step then, at doses high enough to saturate the repair system, one would expect the observed repair after a treatment with a combination of agents to be equal to that from one agent alone. Such is not the case for normal human or excision-deficient XP cells. In the former repair is additive and in the latter repair is usually appreciably less than that observed with either agent alone. Models that attempt to explain these surprising results involve complexes of enzymes and cofactors

  3. Usefulness of DNA repair genes in prediction and potentiation of radiosensitivity in tumor cells

    International Nuclear Information System (INIS)

    Radiotherapy is one of the common treatment modalities for cancer. However, owing to the differences in intrinsic radiosensitivity of the different tumor types, a significant variation in therapeutic response is observed during radiotherapy leading to ineffective killing of tumor cells or occasional adverse effects in normal tissues. Hence, an optimization of radiation dose in clinical practice based on the radiosensitivity of individual patients and tumor types is of paramount importance. From this perspective, prediction of radiosensitivity of tumor tissues and understanding about molecular determinants of radiosensitivity can help in improving the efficacy of radiation therapy. Therefore, in the present study, expression of genes which are involved in DNA damage response and cytoprotective pathways were studied to evaluate their use in predicting the radiosensitivity of tumor cells using six different tumor cells (HT1080, DU145, MCF7, A549, PC3 and HT29). Initially the radiosensitivity profile of these tumor cells has been studied using clonogenic survival assay. Then the expression profile of genes, which are involved in crucial radiation response pathways like, DNA damage, repair, apoptosis and redox regulation were analyzed by real time q-PCR (either 2 Gy or 6 Gy). The fold change in expression was calculated for different genes and was correlated with clonogenic survival. Out of 15 genes analyzed, three genes (HSP70, KU80 and RAD51) showed change in gene expression in accordance with their radiosensitivity. The expression of these three genes also showed a significant positive correlation with survival fraction. The 'r' values observed were 0.97, 0.99, and 0.97 for HSP70, KU80 and RAD51, respectively. Since these genes are involved in DNA repair pathways, we have investigated the effect of inhibition of DNA-PK (a protein involved in the non-homologous end joining and consists of Ku70/KU80 complex and DNA-PKcs), in potentiating the radiation induced damage in

  4. Current focus of stem cell application in retinal repair

    Institute of Scientific and Technical Information of China (English)

    Maria L Alonso-Alonso; Girish Kumar Srivastava

    2015-01-01

    The relevance of retinal diseases, both in society'seconomy and in the quality of people's life who suffer withthem, has made stem cell therapy an interesting topic forresearch. Embryonic stem cells (ESCs), induced pluripotentstem cells (iPSCs) and adipose derived mesenchymal stemcells (ADMSCs) are the focus in current endeavors as asource of different retinal cells, such as photoreceptorsand retinal pigment epithelial cells. The aim is to applythem for cell replacement as an option for treating retinaldiseases which so far are untreatable in their advancedstage. ESCs, despite the great potential for differentiation,have the dangerous risk of teratoma formation as wellas ethical issues, which must be resolved before startinga clinical trial. iPSCs, like ESCs, are able to differentiatein to several types of retinal cells. However, the processto get them for personalized cell therapy has a high costin terms of time and money. Researchers are working toresolve this since iPSCs seem to be a realistic option fortreating retinal diseases. ADMSCs have the advantagethat the procedures to obtain them are easier. Despiteadvancements in stem cell application, there are stillseveral challenges that need to be overcome beforetransferring the research results to clinical application.This paper reviews recent research achievements of theapplications of these three types of stem cells as well asclinical trials currently based on them.

  5. Low-Level Laser Therapy and Calcitonin in Bone Repair: Densitometric Analysis

    OpenAIRE

    Emilia Angela Loschiavo Arisawa; Janete Dias Almeida; Raduan Hage; Claúdia Alessandra Cardoso; Tatiana Pinto Ribeiro; Simone Bustamante Nascimento

    2012-01-01

    The aim of this work was to evaluate the association of low-level laser therapy (LLLT, 830 nm) and calcitonin in bone repair considering that bone healing remains a challenge to health professionals. Calcitonin has antiosteoclastic action and LLLT is a treatment that uses low-level lasers or light-emitting diodes to alter cellular function. Both are used to improve bone healing. Densitometry is a clinical noninvasive valuable tool used to evaluate bone mineral density (BMD). Sixty male rats w...

  6. A DNA Repair BRCA1 Estrogen Receptor and Targeted Therapy in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Adisorn Ratanaphan

    2012-11-01

    Full Text Available BRCA1 is a key mediator of DNA repair pathways and participates in the maintenance of the genomic integrity of cells. The control of DNA damage repair mechanisms by BRCA1 is of great interest since molecular defects in this pathway may reflect a predictive value in terms of a cell’s sensitivity to DNA damaging agents or anticancer drugs. BRCA1 has been found to exhibit a hormone-dependent pattern of expression in breast cells. Wild-type BRCA1 is required for the inhibition of the growth of breast tumor cells in response to the pure steroidal ERα antagonist fulvestrant. Also a loss of BRCA1-mediated transcriptional activation of ERα expression results in increased resistance to ERα antagonists. Platinum-based drugs, poly(ADP-ribose polymerase (PARP inhibitors, and their combination are currently included in chemotherapy regimens for breast cancer. Preclinical and clinical studies in a BRCA1-defective setting have recently indicated a rationale for the use of these compounds against hereditary breast cancers. Initial findings indicate that neoadjuvant use of cisplatin results in high rates of complete pathological response in patients with breast cancer who have BRCA1 mutations. Cisplatin produces a better response in triple-negative breast cancer (TNBC than in non-TNBC diseases in both the neoadjuvant and adjuvant settings. This implies that TNBC cells may harbor a dysfunctional BRCA1 repair pathway.

  7. Stem cell therapy vs. ethics and religion

    OpenAIRE

    Hansen, Paula Melo Paulon; Sloth, Stine Hesselholt

    2009-01-01

    Stem cells are somatic cells that can go through two different kinds of divisions. Symmetric division allows them to divide into undifferentiated cells, whilst asymmetric division produces one undifferentiated cell and a sister cell that will differentiate later on. Human stem cell therapy (HSCT) is a controversial theme in the religious, political, legal, ethical and scientific worlds. Although it is believed by many scientists that stem cell therapy will be able to cure life-threatening dis...

  8. Capacity of ultraviolet-induced DNA repair in human glioma cells

    International Nuclear Information System (INIS)

    A DNA repair abnormality is likely related to an increased incidence of neoplasms in several autosomal recessive diseases such as xeroderma pigmentosum, Fanconi's anemia, Bloom's syndrome and ataxia telangiectasia. In human glioma cells, however, there are only a few reports on DNA repair. In this study, an ultraviolet (UV)-induced DNA repair was examined systematically in many human glioma cells. Two human malignant glioma cell lines (MMG-851, U-251-MG) and 7 human glioma cell strains (4, benign; 3, malignant) of short term culture, in which glial fibrillary acidic protein (GFAP) staining were positive, were used. To investigate the capacity of DNA repair, UV sensitivity was determined by colony formation; excision repair by autoradiography and Cytosine Arabinoside (Ara-C) assay; and post-replication repair by the joining rate of newly synthesized DNA. As a result, the colony-forming abilities of malignant glioma cell lines were lower than those of normal human fibroblasts, but no difference was found between two malignant glioma cell lines. The excision repair of the malignant group (2 cell lines and 3 cell strains) was apparently lower than that of the benign group (4 cell strains). In two malignant glioma cell lines, the excision repair of MMG-851 was lower than that of U-251-MG, and the post-replication repair of MMG-851 was higher than that of U-251-MG. These results were considered to correspond well with colony-forming ability. The results indicate that there are some differences in each human malignant glioma cell in its UV-induced DNA repair mechanism, and that the excision repair of the malignant glioma cells is apparently lower than that of the benign glioma cells. These findings may be useful for diagnosis and treatment. (author)

  9. Mesenchymal Stem Cells and Induced Pluripotent Stem Cells as Therapies for Multiple Sclerosis

    Directory of Open Access Journals (Sweden)

    Juan Xiao

    2015-04-01

    Full Text Available Multiple sclerosis (MS is a chronic, autoimmune, inflammatory demyelinating disorder of the central nervous system that leads to permanent neurological deficits. Current MS treatment regimens are insufficient to treat the irreversible neurological disabilities. Tremendous progress in the experimental and clinical applications of cell-based therapies has recognized stem cells as potential candidates for regenerative therapy for many neurodegenerative disorders including MS. Mesenchymal stem cells (MSC and induced pluripotent stem cell (iPSCs derived precursor cells can modulate the autoimmune response in the central nervous system (CNS and promote endogenous remyelination and repair process in animal models. This review highlights studies involving the immunomodulatory and regenerative effects of mesenchymal stem cells and iPSCs derived cells in animal models, and their translation into immunomodulatory and neuroregenerative treatment strategies for MS.

  10. DNA repair in human xeroderma pigmentosum and chinese hamster cells

    International Nuclear Information System (INIS)

    The investigations described were performed to study the genetic heterogeneity of excision repair-deficient XP (xeroderma pigmentosum) strains and the biochemical defects in their repair processes after irradiation with ultraviolet radiation. (Auth.)

  11. Influence of the thymus on hemopoietic stem cells capability to repair sublethal radiation damages

    International Nuclear Information System (INIS)

    In the course of irradiation of mice bone marrow (300 rad in vitro + 300 rad in vivo) hemopoietic stem cells injury decreases significantly at the irradiation interval of 5 hrs as compared to 30 min interval at the expence of repairment from sublethal radiation damages (the Elkind repair effect). In case of thymectomized mature mice, the capability of hemopoietic stem cells for the Elkind repair is sharply distorted when 2/2-5 months after operation. Thymus transplantation removes thymectomy effect

  12. Stem Cell Therapy in Pediatric Neurological Disorders

    OpenAIRE

    Farnaz Torabian; Arvin Aghayi Nejad; Arash Akhavan Rezayat; Mehran Beiraghi Toosi; Ali Reza Attaei Nakhaie; Hamid Reza Rahimi

    2015-01-01

    Pediatric neurological disorders including muscular dystrophy, cerebral palsy, and spinal cord injury are defined as a heterogenous group of diseases, of which some are known to be genetic. The two significant features represented for stem cells, leading to distinguish them from other cell types are addressed as below: they can renew themselves besides the ability to differentiate into cells with special function as their potency. Researches about the role of stem cells in repair of damaged t...

  13. Mesenchymal stem cells and collagen patches for anteriorcruciate ligament repair

    Institute of Scientific and Technical Information of China (English)

    Benjamin Gantenbein; Neha Gadhari; Samantha CW Chan; Sandro Kohl; Sufian S Ahmad

    2015-01-01

    AIM To investigate collagen patches seeded withmesenchymal stem cells (MSCs) and/or tenocytes (TCs)with regards to their suitability for anterior cruciateligament (ACL) repair.METHODS: Dynamic intraligamentary stabilizationutilizes a dynamic screw system to keep ACL remnantsin place and promote biological healing, supplementedby collagen patches. How these scaffolds interact withcells and what type of benefit they provide has not yetbeen investigated in detail. Primary ACL-derived TCsand human bone marrow derived MSCs were seededonto two different types of 3D collagen scaffolds,Chondro-Gide? (CG) and Novocart? (NC). Cells wereseeded onto the scaffolds and cultured for 7 d eitheras a pure populations or as "premix" containing a 1:1ratio of TCs to MSCs. Additionally, as controls, cells wereseeded in monolayers and in co-cultures on both sidesof porous high-density membrane inserts (0.4 μm). Weanalyzed the patches by real time polymerase chainreaction, glycosaminoglycan (GAG), DNA and hydroxyproline(HYP) content. To determine cell spreadingand adherence in the scaffolds microscopic imagingtechniques, i.e. , confocal laser scanning microscopy(cLSM) and scanning electron microscopy (SEM), wereapplied.RESULTS: CLSM and SEM imaging analysis confirmedcell adherence onto scaffolds. The metabolic cellactivity revealed that patches promote adherenceand proliferation of cells. The most dramatic increasein absolute metabolic cell activity was measuredfor CG samples seeded with tenocytes or a 1:1 cellpremix. Analysis of DNA content and cLSM imagingalso indicated MSCs were not proliferating as nicely astenocytes on CG. The HYP to GAG ratio significantlychanged for the premix group, resulting from a slightlylower GAG content, demonstrating that the cells aremodifying the underlying matrix. Real-time quantitative Gantenbein B et al . Mesenchymal stem cells for ACL repair polymerase chain reaction data indicated that MSCs

  14. Cell and gene therapy in Australia.

    Science.gov (United States)

    Martiniello-Wilks, R; Rasko, J E J

    2007-01-01

    The expansion of human cells to produce cell therapeutic products for the treatment of disease is, with few exceptions, an experimental therapy. Because cell therapies involve a biological product, often with some genetic or other modification, they require extensive pre-clinical research and development. Cell therapy production processes and premises require licensing by the Therapeutic Goods Administration. In this review, timed to coincide with the international meetings of the ISCT and ISSCR in Australia, we describe some promising cell therapies currently under development. PMID:17464751

  15. Cell therapy of refractory Crohn's disease.

    Science.gov (United States)

    Knyazev, O V; Parfenov, A I; Shcherbakov, P L; Ruchkina, I N; Konoplyannikov, A G

    2013-11-01

    We analyzed medium-term efficiency and safety of biological therapy of Crohn's disease, in particular transplantation of allogenic mesenchymal stromal bone marrow cells and anticytokine therapy with selective immunosuppressive agents. It was found that both methods of biological therapy of refractory Crohn's disease resulted in clinical and in some cases endoscopic remission. In most cases, clinical remission was maintained without steroid hormone therapy. Thus, both methods produce comparable clinical results. It was concluded that transplantation of mesenchymal stromal bone marrow cells could be considered as a promising method in the therapy of refractory Crohn's disease comparable by its efficiency with infliximab therapy. PMID:24319711

  16. Stem Cell Therapy for Congestive Heart Failure

    Directory of Open Access Journals (Sweden)

    Gunduz E

    2011-01-01

    Full Text Available IntroductionHeart failure is a major cardiovascular health problem. Coronary artery disease is the leading cause of congestive heart failure (CHF [1]. Cardiac transplantation remains the most effective long-term treatment option, however is limited primarily by donor availability, rejection and infections. Mechanical circulatory support has its own indications and limitations [2]. Therefore, there is a need to develop more effective therapeutic strategies.Recently, regenerative medicine has received considerable scientific attention in the cardiovascular arena. We report here our experience demonstrating the beneficial effects of cardiac stem cell therapy on left ventricular functions in a patient with Hodgkin’s lymphoma (HL who developed CHF due to ischemic heart disease during the course of lymphoma treatment. Case reportA 58-year-old male with relapsed HL was referred to our bone marrow transplantation unit in October 2009. He was given 8 courses of combination chemotherapy with doxorubicin, bleomycin, vincristine, and dacarbazine (ABVD between June 2008 and February 2009 and achieved complete remission. However, his disease relapsed 3 months after completing the last cycle of ABVD and he was decided to be treated with DHAP (cisplatin, cytarabine, dexamethasone followed autologous stem cell transplantation (SCT. After the completion of first course of DHAP regimen, he developed acute myocardial infarction (AMI and coronary artery bypass grafting (CABG was performed. After his cardiac function stabilized, 3 additional courses of DHAP were given and he was referred to our centre for consideration of autologous SCT. Computed tomography scans obtained after chemotherapy confirmed complete remission. Stem cells were collected from peripheral blood after mobilization with 10 µg/kg/day granulocyte colony-stimulating factor (G-CSF subcutaneously. Collection was started on the fifth day of G-CSF and performed for 3 consecutive days. Flow cytometric

  17. Repair effect of transplantation of bone marrow mesenchymal stem cells on liver injury in severe burned rats and its mechanism

    International Nuclear Information System (INIS)

    Objective: To investigate the repair effect of transplantation of bone marrow mesenchymal stem cells (BMSCs) on liver injury in severe burned rats, and to clarify its mechanism. Methods: The BMSCs of rats were isolated, cultured, amplified, identified, and labeled in vitro. 30 Wistar rats were randomly divided into normal control group (n=10), model group (n=10) and cell therapy group (n=10). The burned rat model was established. The BMSCs labeled by chlormethyl-benzamidodialkylcarbocyanine (CM-Dil) were transplanted into the rats in cell therapy group by retro-orbital intravenous injection and the saline was injected into the rats in model group. The general status of all rats were observed. The liver tissues of rats were obtained 2 weeks after transplantation, and the pathohistological changes were observed and the pathohistological scores were detected; the apoptotic rate of liver cells was detected by TUNEL method; the engraftment of BMSCs in liver tissues of the rats was observed under laser scanning confocal microscope. Results: 2 weeks after transplantation, the rats in model group were obviously malaise dispirited and the rats in cell therapy group showed obviously better, and the body weight of the rats in cell therapy group was higher than that in model group (P<0.05). The pathohistological results showed the normal liver lobules of the rats in model group disappeared, and the liver cords disordered, and some liver sinusoids dilated and congested, lymphocytes infiltrated with occasional focal aggregating, and cell edema was found, cytoplasm loose and steatosis were seen in liver tissue. However, the pathohistological changes of liver tissue of the rats in cell therapy group were significantly better than those in model group. The pathohistological score of the rats in cell therapy group was significantly lower than that in model group (P<0.05). The TUNEL staining results showed that there were lots of apoptotic liver cells in liver tissue of the rats in

  18. DNA Repair and Cancer Therapy: Targeting APE1/Ref-1 Using Dietary Agents

    Directory of Open Access Journals (Sweden)

    Julian J. Raffoul

    2012-01-01

    Full Text Available Epidemiological studies have demonstrated the cancer protective effects of dietary agents and other natural compounds isolated from fruits, soybeans, and vegetables on neoplasia. Studies have also revealed the potential for these natural products to be combined with chemotherapy or radiotherapy for the more effective treatment of cancer. In this paper we discuss the potential for targeting the DNA base excision repair enzyme APE1/Ref-1 using dietary agents such as soy isoflavones, resveratrol, curcumin, and the vitamins ascorbate and α-tocopherol. We also discuss the potential role of soy isoflavones in sensitizing cancer cells to the effects of radiotherapy. A comprehensive review of the dual nature of APE1/Ref-1 in DNA repair and redox activation of cellular transcription factors, NF-κB and HIF-1α, is also discussed. Further research efforts dedicated to delineating the role of APE1/Ref-1 DNA repair versus redox activity in sensitizing cancer cells to conventional treatment are warranted.

  19. Paracrine Mechanisms of Mesenchymal Stem Cells in Tissue Repair.

    Science.gov (United States)

    Gnecchi, Massimiliano; Danieli, Patrizia; Malpasso, Giuseppe; Ciuffreda, Maria Chiara

    2016-01-01

    Tissue regeneration from transplanted mesenchymal stromal cells (MSC) either through transdifferentiation or cell fusion was originally proposed as the principal mechanism underlying their therapeutic action. However, several studies have now shown that both these mechanisms are very inefficient. The low MSC engraftment rate documented in injured areas also refutes the hypothesis that MSC repair tissue damage by replacing cell loss with newly differentiated cells. Indeed, despite evidence of preferential homing of MSC to the site of myocardial ischemia, exogenously administered MSC show poor survival and do not persist in the infarcted area. Therefore, it has been proposed that the functional benefits observed after MSC transplantation in experimental models of tissue injury might be related to the secretion of soluble factors acting in a paracrine fashion. This hypothesis is supported by pre-clinical studies demonstrating equal or even improved organ function upon infusion of MSC-derived conditioned medium (MSC-CM) compared with MSC transplantation. Identifying key MSC-secreted factors and their functional role seems a reasonable approach for a rational design of nextgeneration MSC-based therapeutics. Here, we summarize the major findings regarding both different MSC-mediated paracrine actions and the identification of paracrine mediators. PMID:27236669

  20. Differing levels of excision repair in human fetal dermis and brain cells

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, R.E. (Ohio State Univ., Columbus (USA). Dept. of Radiology); D' Ambrosio, S.M. (Ohio State Univ., Columbus (USA). Dept. of Radiology; Ohio State Univ., Columbus (USA). Dept. of Pharmacology)

    1982-01-01

    The levels of DNA excision repair, as measured by unscheduled DNA synthesis (UDS) and the UV-endonuclease sensitive site assay, were compared in cells derived from human fetal brain and dermal tissues. The level of UDS induced following ultraviolet (UV) irradiation was found to be lower (approx. 60%) in the fetal brain cells than in fetal dermal cells. It was determined, using the UV-endonuclease sensitive site assay to confirm the UDS observation, that 50% of the dimers induced by UV in fetal dermal cells were repaired in 8 h. while only 15% were removed in the fetal brain cells during the same period of time. Even after 24 h. only 44% of the dimers induced by UV in the fetal brain cells were repaired, while 65% were removed in the dermal cells. These data suggest that cultured human fetal brain cells exhibit lower levels of excision repair compared to cultured human fetal dermal cells.

  1. An inverse switch in DNA base excision and strand break repair contributes to melphalan resistance in multiple myeloma cells.

    Directory of Open Access Journals (Sweden)

    Mirta M L Sousa

    Full Text Available Alterations in checkpoint and DNA repair pathways may provide adaptive mechanisms contributing to acquired drug resistance. Here, we investigated the levels of proteins mediating DNA damage signaling and -repair in RPMI8226 multiple myeloma cells and its Melphalan-resistant derivative 8226-LR5. We observed markedly reduced steady-state levels of DNA glycosylases UNG2, NEIL1 and MPG in the resistant cells and cross-resistance to agents inducing their respective DNA base lesions. Conversely, repair of alkali-labile sites was apparently enhanced in the resistant cells, as substantiated by alkaline comet assay, autoribosylation of PARP-1, and increased sensitivity to PARP-1 inhibition by 4-AN or KU58684. Reduced base-excision and enhanced single-strand break repair would both contribute to the observed reduction in genomic alkali-labile sites, which could jeopardize productive processing of the more cytotoxic Melphalan-induced interstrand DNA crosslinks (ICLs. Furthermore, we found a marked upregulation of proteins in the non-homologous end-joining (NHEJ pathway of double-strand break (DSB repair, likely contributing to the observed increase in DSB repair kinetics in the resistant cells. Finally, we observed apparent upregulation of ATR-signaling and downregulation of ATM-signaling in the resistant cells. This was accompanied by markedly increased sensitivity towards Melphalan in the presence of ATR-, DNA-PK, or CHK1/2 inhibitors whereas no sensitizing effect was observed subsequent to ATM inhibition, suggesting that replication blocking lesions are primary triggers of the DNA damage response in the Melphalan resistant cells. In conclusion, Melphalan resistance is apparently contributed by modulation of the DNA damage response at multiple levels, including downregulation of specific repair pathways to avoid repair intermediates that could impair efficient processing of cytotoxic ICLs and ICL-induced DSBs. This study has revealed several novel

  2. Repair of gamma-ray-induced DNA base damage in xeroderma pigmentosum cells

    International Nuclear Information System (INIS)

    The repair of DNA damage produced by 137Cs gamma irradiation was measured with a preparation from Micrococcus luteus containing DNA damage-specific endonucleases in combination with alkaline elution. The frequency of these endonuclease sensitive sites (ESS) was determined after 54 or 110 Gy of oxic irradiation in normal and xeroderma pigmentosum (XP) fibroblasts from complementation groups A, C, D, and G. Repair was rapid in all cell strains with greater than 50% repair after 1.5 h of repair incubation. At later repair times, 12-17 h, more ESS remained in XP than in normal cells. The frequency of excess ESS in XP cells was approximately 0.04 per 10(9) Da of DNA per Gy which was equivalent to 10% of the initial ESS produced. The removal of ESS was comparable in XP cells with normal radiosensitivity and XP3BR cells which have been reported to be moderately radiosensitive

  3. Cell-free assay measuring repair DNA synthesis in human fibroblasts

    International Nuclear Information System (INIS)

    Osmotic disruption of confluent cultured human fibroblasts that have been irradiated or exposed to chemical carcinogens allows the specific measurement of repair DNA synthesis using dTTP as a precursor. Fibroblasts similarly prepared from various xeroderma pigmentosum cell lines show the deficiencies of uv-induced DNA synthesis predicted from in vivo studies, while giving normal responses to methylmethanesulfonate. A pyrimidine-dimer-specific enzyme, T4 endonuclease V, stimulated the rate of uv-induced repair synthesis with normal and xeroderma pigmentosum cell lines. This system should prove useful for identifying agents that induce DNA repair, and cells that respond abnormally to such induction. It should also be applicable to an in vitro complementation assay with repair-defective cells and proteins obtained from repair-proficient cells. Finally, by using actively growing fibroblasts and thymidine in the system, DNA replication can be measured and studied in vitro

  4. An application of embryonic skin cells to repair diabetic skin wound: a wound reparation trail.

    Science.gov (United States)

    Qian, De Jian; Guo, Xiang Kai; Duan, Hui Chuan; Han, Zhi Hua; Meng, Fei; Liu, Ju; Wang, Yan

    2014-12-01

    Cell therapy has shown its power to promote diabetic chronic wound healing. However, problems of scar formation and loss of appendages have not yet been solved. Our study aims to explore the potential of using embryonic skin cells (ESkCs) to repair diabetic wounds. Circular wound was created on the back of the diabetic mice, and ESkCs stained with CM-DIL were transplanted into the wound. Wound area was recorded at the day 4, 7, 11, and 14 after transplantation. The tissue samples were obtained at week 1, 2, and 3, and the tissue sections were stained by transforming growth factor β1 (TGF-β1), TGF-β3, vascular endothelial growth factor (VEGF), and CD31. The new skin formed on the wound of the diabetic mice with ESkC treatment at week 1 but not on the wounds of the non-treatment group. The histological scores of diabetic group with ESkC treatment were significantly better than the non-treatment group (P hair follicles formation, and angiogenesis. The expression of TGF-β1 and VEGF in ESkC-treated groups was noticeable in week 1 but disappeared in week 2. TGF-β3 was not expressed at week 1 but expressed markedly around hair follicles in week 2 in ESkC-treated groups. Our study demonstrated that ESkCs are capable of developing new skin with appendage restoration to repair the diabetic wounds. PMID:25030484

  5. Stem Cell Therapy for Heart Failure

    OpenAIRE

    Michler, Robert E.

    2013-01-01

    The last decade has witnessed the publication of a large number of clinical trials primarily using bone marrow-derived stem cells as the injected cell. These “first-generation” clinical trials have advanced our understanding and shown us that (1) cell therapy is safe, (2) cell therapy has been modestly effective, and (3) in humans, bone marrow-derived stem cells do not transdifferentiate into cardiomyocytes or new blood vessels (or at least in sufficient numbers to have any effect).

  6. Cell Therapy for Parkinson’s Disease

    OpenAIRE

    Morizane, Asuka; Takahashi, Jun

    2016-01-01

    In Parkinson’s disease (PD), dopamine neurons in the substantia nigra are degenerated and lost. Cell therapy for PD replaces the lost dopamine neurons by transplanting donor dopamine neural progenitor cells. Cell therapy for PD has been performed in the clinic since the 1980s and uses donor cells from the mesencephalon of aborted embryos. Regenerative medicine for PD using induced pluripotent stem (iPS) cell technology is drawing attention, because it offers a limitless and more advantageous ...

  7. Cell viability and repair systems in mammal cells

    International Nuclear Information System (INIS)

    Synchronized cell cultures of mice are irradiated with 4,0J/m2 ultraviolet light at different times. The possible mechanisms involved in the recuperation of the cellular survival observed, are discussed. (M.A.)

  8. Repair-deficient xeroderma pigmentosum cells made UV light resistant by fusion with X-ray-inactivated Chinese hamster cells.

    OpenAIRE

    Karentz, D; Cleaver, J.E.

    1986-01-01

    Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The hybrid cells exhibited UV resistance and DNA repair characteristics comparable to those expressed by CHO cells, and their DNA had greater homology with CHO DNA than did the DNA from XP cells. Cont...

  9. More Than Tiny Sacks: Stem Cell Exosomes as Cell-Free Modality for Cardiac Repair.

    Science.gov (United States)

    Kishore, Raj; Khan, Mohsin

    2016-01-22

    Stem cell therapy provides immense hope for regenerating the pathological heart, yet has been marred by issues surrounding the effectiveness, unclear mechanisms, and survival of the donated cell population in the ischemic myocardial milieu. Poor survival and engraftment coupled to inadequate cardiac commitment of the adoptively transferred stem cells compromises the improvement in cardiac function. Various alternative approaches to enhance the efficacy of stem cell therapies and to overcome issues with cell therapy have been used with varied success. Cell-free components, such as exosomes enriched in proteins, messenger RNAs, and miRs characteristic of parental stem cells, represent a potential approach for treating cardiovascular diseases. Recently, exosomes from different kinds of stem cells have been effectively used to promote cardiac function in the pathological heart. The aim of this review is to summarize current research efforts on stem cell exosomes, including their potential benefits and limitations to develop a potentially viable therapy for cardiovascular problems. PMID:26838317

  10. Further proof of the plasticity of adult stem cells and their role in tissue repair

    OpenAIRE

    Prockop, Darwin J.

    2003-01-01

    In this issue, De Bari et al. (2003) present elegant data to counter the recent claims that adult stem cells have a limited plasticity. Further, they provide evidence that adult stem cells can seek out damaged tissues and repair them.

  11. A biophysical model of cell evolution after cytotoxic treatments: Damage, repair and cell response.

    Science.gov (United States)

    Tomezak, M; Abbadie, C; Lartigau, E; Cleri, F

    2016-01-21

    We present a theoretical agent-based model of cell evolution under the action of cytotoxic treatments, such as radiotherapy or chemotherapy. The major features of cell cycle and proliferation, cell damage and repair, and chemical diffusion are included. Cell evolution is based on a discrete Markov chain, with cells stepping along a sequence of discrete internal states from 'normal' to 'inactive'. Probabilistic laws are introduced for each type of event a cell can undergo during its life: duplication, arrest, senescence, damage, reparation, or death. We adjust the model parameters on a series of cell irradiation experiments, carried out in a clinical LINAC, in which the damage and repair kinetics of single- and double-strand breaks are followed. Two showcase applications of the model are then presented. In the first one, we reconstruct the cell survival curves from a number of published low- and high-dose irradiation experiments. We reobtain a very good description of the data without assuming the well-known linear-quadratic model, but instead including a variable DSB repair probability. The repair capability of the model spontaneously saturates to an exponential decay at increasingly high doses. As a second test, we attempt to simulate the two extreme possibilities of the so-called 'bystander' effect in radiotherapy: the 'local' effect versus a 'global' effect, respectively activated by the short-range or long-range diffusion of some factor, presumably secreted by the irradiated cells. Even with an oversimplified simulation, we could demonstrate a sizeable difference in the proliferation rate of non-irradiated cells, the proliferation acceleration being much larger for the global than the local effect, for relatively small fractions of irradiated cells in the colony. PMID:26549470

  12. Cell Therapy in Chagas Disease

    Directory of Open Access Journals (Sweden)

    Antonio C. Campos de Carvalho

    2009-01-01

    Full Text Available Chagas disease which is caused by the parasite Trypanosoma cruzi is an important cause of cardiomyopathy in Latin America. In later stages chagasic cardiomyopathy is associated with congestive heart failure which is often refractory to medical therapy. In these individuals heart transplantation has been attempted. However, this procedure is fraught with many problems attributable to the surgery and the postsurgical administration of immunosuppressive drugs. Studies in mice suggest that the transplantation of bone-marrow-derived cells ameliorates the inflammation and fibrosis in the heart associated with this infection. Cardiac magnetic resonance imaging reveals that bone marrow transplantation ameliorates the infection induced right ventricular enlargement. On the basis of these animal studies the safety of autologous bone marrow transplantation has been assessed in patients with chagasic end-stage heart disease. The initial results are encouraging and more studies need to be performed.

  13. Defective repair of gamma-ray-induced DNA damage in xeroderma pigmentosum cells

    International Nuclear Information System (INIS)

    The bromouracil-photolysis technique has been used to estimate the sizes of the repaired regions in normal human and xeroderma pigmentosum (XP) cells irradiated by γ-rays aerobically or anoxically. After one and a half hours of incubation, single-strand breaks were repaired and the repaired regions were small - one to two BrUra residues -for cells irradiated aerobically or anoxically. After a 20-hour incubation, the repaired region in normal cells showed a component mimicking U.V.-repair. There were large patches (approximately 30 BrUra residues) in the approximate ratios of one per six chain breaks for aerobic irradiation and one per three chain breaks for anoxic irradiation. XP cells, however, only showed large patches at 20 hours if they had been irradiated aerobically. Such regions could not be detected in XP cells irradiated anoxically. These results indicate (1) that some part of ionizing damage mimics excision of U.V. damage in that the repair patches are large and the repair takes an appreciable time; (2) the types of such damage depend on whether the irradiation is done aerobically or anoxically; and (3) XP cells are defective in repairing a component of anoxic damage. (author)

  14. Effects of camptothecin on double-strand break repair by non-homologous end-joining in DNA mismatch repair-deficient human colorectal cancer cell lines

    OpenAIRE

    Jacob, Sandrine; Miquel, Catherine; Sarasin, Alain; Praz, Françoise

    2005-01-01

    Loss of a functional mismatch repair (MMR) system in colorectal cancer (CRC) cells is associated with microsatellite instability and increased sensitivity to topoisomerase inhibitors. In this study, we have investigated whether a defect in double-strand break (DSB) repair by non-homologous end-joining (NHEJ) could explain why MMR-deficient CRC cells are hypersensitive to camptothecin (CPT), a topoisomerase I inhibitor. To evaluate the efficiency and the fidelity of DSB repair, we have transie...

  15. DNA excision repair in cell extracts from human cell lines exhibiting hypersensitivity to DNA-damaging agents

    International Nuclear Information System (INIS)

    Whole cell extracts from human lymphoid cell lines can perform in vitro DNA repair synthesis in plasmids damaged by agents including UV or cis-diamminedichloroplatinum(II) (cis-DDP). Extracts from xeroderma pigmentosum (XP) cells are defective in repair synthesis. We have now studied in vitro DNA repair synthesis using extracts from lymphoblastoid cell lines representing four human hereditary syndromes with increased sensitivity to DNA-damaging agents. Extracts of cell lines from individuals with the sunlight-sensitive disorders dysplastic nevus syndrome or Cockayne's syndrome (complementation groups A and B) showed normal DNA repair synthesis in plasmids with UV photoproducts. This is consistent with in vivo measurements of the overall DNA repair capacity in such cell lines. A number of extracts were prepared from two cell lines representing the variant form of XP (XP-V). Half of the extracts prepared showed normal levels of in vitro DNA repair synthesis in plasmids containing UV lesions, but the remainder of the extracts from the same cell lines showed deficient repair synthesis, suggesting the possibility of an unusually labile excision repair protein in XP-V. Fanconi's anemia (FA) cells show cellular hypersensitivity to cross-linking agents including cis-DDP. Extracts from cell lines belonging to two different complementation groups of FA showed normal DNA repair synthesis in plasmids containing cis-DDP or UV adducts. Thus, there does not appear to be an overall excision repair defect in FA, but the data do not exclude a defect in the repair of interstrand DNA cross-links

  16. Repair of radiation damages to haemopoietic stem cells of mouse embryonal liver: kinetic aspects

    International Nuclear Information System (INIS)

    The method of fractionated irradiation was used to study kinetic aspects of repair of sublethal radiation damages in precursor cells from mouse embryonal liver that form in vivo colonies on 8th and 11th days. It was shown that 11-day CFUs had a lesser ability to repair sublethal radiation damages than 8-day ones at different time-intervals between radiation fractions (from 2 to 6 h). These two CFUs subpopulations differed also in the repair kinetics

  17. DNA Repair Gene Polymorphisms May Be Associated with Prognosis of Upper Urinary Tract Transitional Cell Carcinoma

    OpenAIRE

    Miwa Sasaki; Shigeru Sakano; Naoko Okayama; Jumpei Akao; Tomohiko Hara; Yoshihisa Kawai; Chietaka Ohmi; Yuji Hinoda; Katsusuke Naito

    2008-01-01

    Upper urinary tract transitional cell carcinoma (UUT-TCC) is quite an uncommon disease, and its prognosis differs among individuals irrespective of tumor stage. DNA repair gene polymorphisms are reported to result in the modulation of the repair capacity and might influence the prognosis of UUT-TCC. We examined the associations between functional polymorphisms in five DNA repair genes, and the prognosis of UUT-TCC in 103 UUT-TCC patients. Variant alleles in xeroderma pigmentosum complementati...

  18. Stem cells: potential source for retinal repair and regeneration Células tronco: fonte potencial para a regeneração retiniana

    OpenAIRE

    Leonardo Torquetti; Paula Castanheira; Alfredo Miranda Góes; Nehemy Marcio

    2007-01-01

    Stem cells have been studied in several fields of Medicine, and their applications are not too far from the clinical practice. Retinal impairment by neuronal death has been considered incurable due to the limited regenerative capacity of the central nervous system. The capacity of stem cells to regenerate tissues, as well as their plasticity makes them a potential source for retinal repair. The stem cells are a great promise for the therapy of inherited retinal disorders and retinal-neuronal ...

  19. Cell sensitivity to exogenous agents as a basis of tumor therapy

    International Nuclear Information System (INIS)

    Dose-survival relationship of mammalian cells to exogeous agents, as determined by in vitro and in vivo assays, provides a bases for tumor therapy. The dose-survival response can be altered by several cellular factors: (1) cell cycle dependence of sensitivity, (2) growth phase dependence of sensitivity, (3) repair of sublethal damage, (4) repair of potentially lethal damage, and (5) cell-drug interaction. All of these factors are deeply involved in a therapeutic design for tumors. Repair of potentially lethal damage and cell-drug interaction, and the most recent development in studies of these factors, were mentioned in relation to bleomycin action on mammalian cells. On the basis of these cellular factors the pros and cons of different therapeutic designs for bleomycin were discussed. (auth.)

  20. Renal replacement therapies after abdominal aortic aneurysm repair--a review.

    Science.gov (United States)

    Hudorović, Narcis; Lovricević, Ivo; Brkić, Petar; Ahel, Zaky; Vicić-Hudorović, Visnja

    2011-09-01

    The objective of this review is to assess the incidence of postoperative acute renal failure that necessitates the application of hemofiltration and to determine the factors that influence the outcome in patients undergoing surgical repair of abdominal aortic aneurysm. In addition, the review aims to assess the outcomes of postoperative early hemofiltration as compared to late intensive hemofiltration. Different forms of renal replacement therapies for use in abdominal aortic aneurysm surgery patients are discussed. Electronic literature searches were performed using Pubmed, Medline, Embase, Sumsearch, Cinahil, The Cochrane Central Register of Controlled Trials and Excerpta Medica. The search identified 419 potentially eligible studies, of which 119 were excluded based on the title and abstract. Of the remaining 300 studies, full articles were collected and re-evaluated. Forty-five articles satisfied our inclusion criteria, of which only 12 were of the IA Level of evidence. The search results indicated that the underlying disease, its severity and stage, the etiology of acute renal failure, clinical and hemodynamic status of the patient, the resources available, and different costs of therapy might all influence the choice of the renal replacement therapy strategy. However, clear guidelines on renal replacement therapy duration are still lacking. Moreover, it is not known whether in acute renal failure patients undergoing abdominal aortic aneurysm surgery, renal replacement therapy modalities can eliminate significant amounts of clinically relevant inflammatory mediators. This review gives current information available in the literature on the possible mechanisms underlying acute renal failure and recent developments in continuous renal replacement treatment modalities. PMID:22384777

  1. Nucleotide Excision Repair and Vitamin D-Relevance for Skin Cancer Therapy.

    Science.gov (United States)

    Pawlowska, Elzbieta; Wysokinski, Daniel; Blasiak, Janusz

    2016-01-01

    Ultraviolet (UV) radiation is involved in almost all skin cancer cases, but on the other hand, it stimulates the production of pre-vitamin D3, whose active metabolite, 1,25-dihydroxyvitamin D3 (1,25VD3), plays important physiological functions on binding with its receptor (vitamin D receptor, VDR). UV-induced DNA damages in the form of cyclobutane pyrimidine dimers or (6-4)-pyrimidine-pyrimidone photoproducts are frequently found in skin cancer and its precursors. Therefore, removing these lesions is essential for the prevention of skin cancer. As UV-induced DNA damages are repaired by nucleotide excision repair (NER), the interaction of 1,25VD3 with NER components can be important for skin cancer transformation. Several studies show that 1,25VD3 protects DNA against damage induced by UV, but the exact mechanism of this protection is not completely clear. 1,25VD3 was also shown to affect cell cycle regulation and apoptosis in several signaling pathways, so it can be considered as a potential modulator of the cellular DNA damage response, which is crucial for mutagenesis and cancer transformation. 1,25VD3 was shown to affect DNA repair and potentially NER through decreasing nitrosylation of DNA repair enzymes by NO overproduction by UV, but other mechanisms of the interaction between 1,25VD3 and NER machinery also are suggested. Therefore, the array of NER gene functioning could be analyzed and an appropriate amount of 1.25VD3 could be recommended to decrease UV-induced DNA damage important for skin cancer transformation. PMID:27058533

  2. Nucleotide Excision Repair and Vitamin D—Relevance for Skin Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Elzbieta Pawlowska

    2016-04-01

    Full Text Available Ultraviolet (UV radiation is involved in almost all skin cancer cases, but on the other hand, it stimulates the production of pre-vitamin D3, whose active metabolite, 1,25-dihydroxyvitamin D3 (1,25VD3, plays important physiological functions on binding with its receptor (vitamin D receptor, VDR. UV-induced DNA damages in the form of cyclobutane pyrimidine dimers or (6-4-pyrimidine-pyrimidone photoproducts are frequently found in skin cancer and its precursors. Therefore, removing these lesions is essential for the prevention of skin cancer. As UV-induced DNA damages are repaired by nucleotide excision repair (NER, the interaction of 1,25VD3 with NER components can be important for skin cancer transformation. Several studies show that 1,25VD3 protects DNA against damage induced by UV, but the exact mechanism of this protection is not completely clear. 1,25VD3 was also shown to affect cell cycle regulation and apoptosis in several signaling pathways, so it can be considered as a potential modulator of the cellular DNA damage response, which is crucial for mutagenesis and cancer transformation. 1,25VD3 was shown to affect DNA repair and potentially NER through decreasing nitrosylation of DNA repair enzymes by NO overproduction by UV, but other mechanisms of the interaction between 1,25VD3 and NER machinery also are suggested. Therefore, the array of NER gene functioning could be analyzed and an appropriate amount of 1.25VD3 could be recommended to decrease UV-induced DNA damage important for skin cancer transformation.

  3. Nucleotide Excision Repair and Vitamin D—Relevance for Skin Cancer Therapy

    Science.gov (United States)

    Pawlowska, Elzbieta; Wysokinski, Daniel; Blasiak, Janusz

    2016-01-01

    Ultraviolet (UV) radiation is involved in almost all skin cancer cases, but on the other hand, it stimulates the production of pre-vitamin D3, whose active metabolite, 1,25-dihydroxyvitamin D3 (1,25VD3), plays important physiological functions on binding with its receptor (vitamin D receptor, VDR). UV-induced DNA damages in the form of cyclobutane pyrimidine dimers or (6-4)-pyrimidine-pyrimidone photoproducts are frequently found in skin cancer and its precursors. Therefore, removing these lesions is essential for the prevention of skin cancer. As UV-induced DNA damages are repaired by nucleotide excision repair (NER), the interaction of 1,25VD3 with NER components can be important for skin cancer transformation. Several studies show that 1,25VD3 protects DNA against damage induced by UV, but the exact mechanism of this protection is not completely clear. 1,25VD3 was also shown to affect cell cycle regulation and apoptosis in several signaling pathways, so it can be considered as a potential modulator of the cellular DNA damage response, which is crucial for mutagenesis and cancer transformation. 1,25VD3 was shown to affect DNA repair and potentially NER through decreasing nitrosylation of DNA repair enzymes by NO overproduction by UV, but other mechanisms of the interaction between 1,25VD3 and NER machinery also are suggested. Therefore, the array of NER gene functioning could be analyzed and an appropriate amount of 1.25VD3 could be recommended to decrease UV-induced DNA damage important for skin cancer transformation. PMID:27058533

  4. Repair of vesicovaginal fistula caused by radiation therapy with labia maiora skin flap

    Directory of Open Access Journals (Sweden)

    Stanojević Dušan

    2010-01-01

    Full Text Available Introduction Vesicovaginal fistula can occur after delivery, gynaecologic or urologic surgery, irradiation therapy or as destruction caused by a tumour or trauma. The main problem after irradiation is decreased elasticity of the tissue around the fistula. We present our experience in the treatment of three patients with vesicovaginal fistula using a labia maiora skin flap. Case Outline From May 2007 to January 2008 three patients with vesicovaginal fistula were treated using labia maiora skin flap. The fistulae occurred after mean 19 months (11, 20 and 26 months following irradiation therapy applied to treat malignant disease. The mean age of the patients was 54 years (47, 53 and 62 years. The mean diameter of the fistulae was 3.5 cm (2, 4 and 4.5 cm. Using transvaginal approch, all devitalized and fibrous tissue was removed with the closure of the bladder wall. The labia maiora skin flap with good vascularization was transposed to close the defect and anastomozed to the vagina. The mean follow-up was 16 months (13, 17 and 18 months. Labia maiora skin flap size was mean 3.7 cm (2.6, 3.7 and 4.8 cm. We achieved satisfactory outcome in all patients. There were neither postoperative complications nor fistula recurrence. Conclusion Labia maiora skin flap presents a good alternative for surgical treatment of vesicovaginal fistula. The flap is more adequate for larger defects and for the repair of fibrously changed vaginal wall which is present after irradiation therapy. .

  5. Repair of potentially lethal radiation damage in human squamous carcinoma cells after chronic hypoxia

    International Nuclear Information System (INIS)

    The purpose of this study was to examine the repair of radiation-induced potentially lethal damage in A431 and CaSki cells after chronic hypoxia. Cells in exponential phase are subjected to hypoxia (4 h of hypoxia. The repair returned to aerobic control level by 3 h of reoxygenation. PLDR of A431 cells reached maximum at about 9 h after irradiation in cells reoxygenated for 10 min after hypoxia. However, the repair is maximum at 6 h in cells reoxygenated for 3 h after hypoxia and in aerobic cells not previously exposed to hypoxia. Reoxygenation after chronic hypoxia did not affect the PLDR capacity and repair kinetics of CaSki cells. The results suggest that radiosensitization by reoxygenation after chronic hypoxia is not related to inhibition of PLDR. 14 refs., 3 figs

  6. Repair of DNA damage in mammalian cells after treatment with UV and dimethyl sulphate: discrimination between nucleotide and base excision repair by their temperature dependence.

    Science.gov (United States)

    Hjertvik, M; Erixon, K; Ahnström, G

    1998-03-01

    Alkylating agents have been reported to give rise to both short and long patches of repair. The reason for the different patch sizes is not known. One possibility is that alkylating agents can trigger both base and nucleotide excision repair. Another possibility is that base excision repair itself can result in different patch sizes. Recognition and incision at lesions is the rate limiting step in excision repair. In order to discriminate between base and nucleotide excision repair it would be desirable to be able to distinguish between different incision activities. In order to accurately measure incision rates, the rejoining of the strand-breaks formed must be inhibited. We have used two inhibitors, aphidicolin and 3-aminobenzamide. Aphidicolin, an inhibitor of DNA polymerases alpha/delta/epsilon. caused accumulation of single-strand breaks both after UV and dimethylsulphate. 3-Aminobenzamide, an inhibitor of poly(ADP-ribose)-polymerase caused accumulation of single-strand breaks only after alkylating agents and is thus specific for base excision repair. Enzymatic activities can be characterised by their activation energy. In order to discriminate between base and nucleotide excision repair the temperature dependence of incision activities was determined. When the temperature is decreased, the incision rate is reduced to a larger extent for UV than for DMS-induced repair. Incisions in UV-irradiated cells are practically cut off at temperatures of 15 degrees C and below, whereas DMS-exposed cells still are actively repairing at this temperature. In DMS treated cells the temperature dependence was the same whether aphidicolin or 3-aminobenzamide was used, speaking against an involvement of nucleotide excision repair. In addition, cell lines deficient in nucleotide excision repair responded in the same way to aphidicolin after DMS treatment as normal cells and were able to make incisions at 15 degrees C. This indicates that nucleotide excision repair is not to any

  7. Low-Level Laser Therapy and Calcitonin in Bone Repair: Densitometric Analysis

    Directory of Open Access Journals (Sweden)

    Tatiana Pinto Ribeiro

    2012-01-01

    Full Text Available The aim of this work was to evaluate the association of low-level laser therapy (LLLT, 830 nm and calcitonin in bone repair considering that bone healing remains a challenge to health professionals. Calcitonin has antiosteoclastic action and LLLT is a treatment that uses low-level lasers or light-emitting diodes to alter cellular function. Both are used to improve bone healing. Densitometry is a clinical noninvasive valuable tool used to evaluate bone mineral density (BMD. Sixty male rats were submitted to bone defect with a trephine bur, randomly divided into four groups of 15 animals each: control (C; synthetic salmon calcitonin (Ca; LLLT (La; LLLT combined with calcitonin (LaCa. Animals from Ca and LaCa received 2 UI/Kg synthetic salmon calcitonin intramuscularly on alternate days after surgery. Animals from groups La and LaCa were treated with infrared LLLT (830 nm, 10 mW, 20 J/cm2, 6 s, contact mode. Five animals from each group were euthanized 7, 14, and 21 days after surgery and bone defects were analyzed by densitometry. Statistical analysis showed a significant difference in BMD values in LaCa group at 7 and 21 days (=0,005. The results of the densitometric study showed that LLLT (830 nm combined with calcitonin improved bone repair.

  8. Personal characteristics, therapy modalities and individual DNA repair capacity as predictive factors of acute skin toxicity in an unselected cohort of breast cancer patients receiving radiotherapy

    International Nuclear Information System (INIS)

    Background and purpose: Intrinsic and extrinsic factors can affect the occurrence of side effects of radiotherapy. The influence of therapy modalities, personal characteristics and individual DNA repair capacity on the risk of acute skin toxicity was thus evaluated. Materials and methods: In a prospective study of 478 female breast cancer patients receiving adjuvant radiotherapy of the breast after breast-conserving surgery, acute skin toxicity was documented systematically using a modified version of the common toxicity criteria. Prognostic personal and treatment characteristics were identified for the entire cohort. Individual DNA repair capacity was determined in a subgroup of 113 patients with alkaline comet assay using phytohemagglutinin stimulated lymphocytes. Using proportional hazards analysis to account for cumulative biologically effective radiation dose, the hazard for the development of acute skin reactions (moist desquamation) associated with DNA repair capacity was modeled. Results: Of the 478 participants, 84 presented with acute reactions by the end of treatment. Higher body mass index was significantly associated with an increased risk for acute reactions (hazard ratio=1.09 per 1 kg/m2), adjusted for treating hospital and photon beam quality. The comet assay parameters examined, including background DNA damage in non-irradiated cells, DNA damage induced by 5 Gy, and DNA repair capacity, were not significantly associated with risk of acute skin toxicity. Conclusions: Higher BMI is predictive of acute skin toxicity, however, individual repair parameters as determined by the alkaline comet assay are not informative enough. More comprehensive analyses including late effects of radiotherapy and repair kinetics optimized for different radiation-induced DNA lesions are warranted

  9. Cell-Based Therapies for Diabetic Complications

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    Stella Bernardi

    2012-01-01

    Full Text Available In recent years, accumulating experimental evidence supports the notion that diabetic patients may greatly benefit from cell-based therapies, which include the use of adult stem and/or progenitor cells. In particular, mesenchymal stem cells and the circulating pool of endothelial progenitor cells have so far been the most studied populations of cells proposed for the treatment of vascular complications affecting diabetic patients. We review the evidence supporting their use in this setting, the therapeutic benefits that these cells have shown so far as well as the challenges that cell-based therapies in diabetic complications put out.

  10. Ultrafast chemical repair of DNA single and double strand break precursors in irradiated V79 cells

    International Nuclear Information System (INIS)

    The fast kinetics of reactions of free radical precursors of DNA single strand breaks (ssb) and double strand breaks (dsb) have been determined in Chinese hamster V79 cells by fast mixing and irradiation methods using the alkaline unwinding technique to assay breaks. Fast chemical repair of oxygen-dependent ssb and dsb precursors was observed and approached completion within 10 to 20 ms of irradiation. Treatment of cells with the glutathione synthesis blocking agent, buthionine sulphoximine, showed that approximately half of the chemical repair was attributable to intracellular non-protein thiols. The nature of the residual repair is obscure, but it is apparently not attributable to non-protein thiols. Similar repair rates and thiol dependences were also found for cell kill. With all three endpoints, oxygen competes with and blocks the chemical repair. 36 refs., 6 figs., 1 tab

  11. The Fanconi anemia pathway: Repairing the link between DNA damage and squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Romick-Rosendale, Lindsey E. [Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children' s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229 (United States); Lui, Vivian W.Y.; Grandis, Jennifer R. [Department of Otolaryngology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Wells, Susanne I., E-mail: Susanne.Wells@cchmc.org [Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children' s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229 (United States)

    2013-03-15

    Fanconi anemia (FA) is a rare inherited recessive disease caused by mutations in one of fifteen genes known to encode FA pathway components. In response to DNA damage, nuclear FA proteins associate into high molecular weight complexes through a cascade of post-translational modifications and physical interactions, followed by the repair of damaged DNA. Hematopoietic cells are particularly sensitive to the loss of these interactions, and bone marrow failure occurs almost universally in FA patients. FA as a disease is further characterized by cancer susceptibility, which highlights the importance of the FA pathway in tumor suppression, and will be the focus of this review. Acute myeloid leukemia is the most common cancer type, often subsequent to bone marrow failure. However, FA patients are also at an extreme risk of squamous cell carcinoma (SCC) of the head and neck and gynecological tract, with an even greater incidence in those individuals who have received a bone marrow transplant and recovered from hematopoietic disease. FA tumor suppression in hematopoietic versus epithelial compartments could be mechanistically similar or distinct. Definition of compartment specific FA activities is now critical to assess the effects of today's bone marrow failure treatments on tomorrow's solid tumor development. It is our hope that current therapies can then be optimized to decrease the risk of malignant transformation in both hematopoietic and epithelial cells. Here we review our current understanding of the mechanisms of action of the Fanconi anemia pathway as it contributes to stress responses, DNA repair and squamous cell carcinoma susceptibility.

  12. Human umbilical cord mesenchymal stem cells promote peripheral nerve repair via paracrine mechanisms

    Directory of Open Access Journals (Sweden)

    Zhi-yuan Guo

    2015-01-01

    Full Text Available Human umbilical cord-derived mesenchymal stem cells (hUCMSCs represent a promising young-state stem cell source for cell-based therapy. hUCMSC transplantation into the transected sciatic nerve promotes axonal regeneration and functional recovery. To further clarify the paracrine effects of hUCMSCs on nerve regeneration, we performed human cytokine antibody array analysis, which revealed that hUCMSCs express 14 important neurotrophic factors. Enzyme-linked immunosorbent assay and immunohistochemistry showed that brain-derived neurotrophic factor, glial-derived neurotrophic factor, hepatocyte growth factor, neurotrophin-3, basic fibroblast growth factor, type I collagen, fibronectin and laminin were highly expressed. Treatment with hUCMSC-conditioned medium enhanced Schwann cell viability and proliferation, increased nerve growth factor and brain-derived neurotrophic factor expression in Schwann cells, and enhanced neurite growth from dorsal root ganglion explants. These findings suggest that paracrine action may be a key mechanism underlying the effects of hUCMSCs in peripheral nerve repair.

  13. Understanding the application of stem cell therapy in cardiovascular diseases

    Directory of Open Access Journals (Sweden)

    Sharma RK

    2012-10-01

    Full Text Available Rakesh K Sharma, Donald J Voelker, Roma Sharma, Hanumanth K ReddyUniversity of Arkansas for Medical Sciences, Medical Center of South Arkansas, El Dorado, AR, USAAbstract: Throughout their lifetime, an individual may sustain many injuries and recover spontaneously over a period of time, without even realizing the injury in the first place. Wound healing occurs due to a proliferation of stem cells capable of restoring the injured tissue. The ability of adult stem cells to repair tissue is dependent upon the intrinsic ability of tissues to proliferate. The amazing capacity of embryonic stem cells to give rise to virtually any type of tissue has intensified the search for similar cell lineage in adults to treat various diseases including cardiovascular diseases. The ability to convert adult stem cells into pluripotent cells that resemble embryonic cells, and to transplant those in the desired organ for regenerative therapy is very attractive, and may offer the possibility of treating harmful disease-causing mutations. The race is on to find the best cells for treatment of cardiovascular disease. There is a need for the ideal stem cell, delivery strategies, myocardial retention, and time of administration in the ideal patient population. There are multiple modes of stem cell delivery to the heart with different cell retention rates that vary depending upon method and site of injection, such as intra coronary, intramyocardial or via coronary sinus. While there are crucial issues such as retention of stem cells, microvascular plugging, biodistribution, homing to myocardium, and various proapoptotic factors in the ischemic myocardium, the regenerative potential of stem cells offers an enormous impact on clinical applications in the management of cardiovascular diseases.Keywords: stem cell therapy, stem cell delivery, cardiovascular diseases, myocardial infarction, cardiomyopathy

  14. Studies on bleomycin-induced repair DNA synthesis in permeable mouse ascites sarcoma cells.

    Directory of Open Access Journals (Sweden)

    Mori,Shigeru

    1989-04-01

    Full Text Available To study the mechanism of DNA excision repair, a DNA repair system employing permeable mouse sarcoma (SR-C3H/He cells was established and characterized. SR-C3H/He cells were permeabilized with a 0.0175% Triton X-100 solution. The permeable cells were treated with 1 mM ATP and 0.11 mM bleomycin, and then washed thoroughly to remove ATP and bleomycin. Repair DNA synthesis occurred in the bleomycin-damaged, permeable SR-C3H/He cells when incubated with ATP and four deoxyribonucleoside triphosphates. The repair nature of the DNA synthesis was confirmed by the BrdUMP density shift technique, and by the reduced sensitivity of the newly synthesized DNA to Escherichia coli exonuclease III. The DNA synthesis was optimally enhanced by addition of 0.08 M NaCl. Studies using selective inhibitors of DNA synthesis showed that aphidicolin-sensitive DNA polymerase (DNA polymerase alpha and/or delta and DNA polymerase beta were involved in the repair process. The present DNA repair system is thought to be useful to study nuclear DNA damage by bleomycin, removal of the damaged ends by an exonuclease, repair DNA synthesis by DNA polymerases and repair patch ligation by DNA ligase(s.

  15. Double strand break repair: two mechanisms in competition but tightly linked to cell cycle

    International Nuclear Information System (INIS)

    DNA double strand breaks (DSB) are highly toxic damage although they can be induced to create genetic diversity. Two distinct pathways can repair DSB: Homologous Recombination (HR) and Non Homologous End Joining (NHEJ). If un- or mis-repaired, this damage can lead to cancer. Thus, it is essential to investigate how these two pathways are regulated for DSB repair. NHEJ inhibition leads to HR DSB repair stimulation. However, this channeling to HR is tightly linked to cell cycle since NHEJ and HR are active in G1/early S and late S/G2, respectively. Our results suggest that G1-unrepaired DSB go through S phase to be repaired by HR in G2. Those results allow a better understanding of DSB repair mechanisms regulation. (author)

  16. The indirect effect of radiation reduces the repair fidelity of NHEJ as verified in repair deficient CHO cell lines exposed to different radiation qualities and potassium bromate

    Energy Technology Data Exchange (ETDEWEB)

    Bajinskis, Ainars, E-mail: ainars.bajinskis@gmt.su.se [Centre for Radiation Protection Research, Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm (Sweden); Olsson, Gunilla; Harms-Ringdahl, Mats [Centre for Radiation Protection Research, Department of Genetics, Microbiology and Toxicology, Stockholm University, S-10691 Stockholm (Sweden)

    2012-03-01

    The complexity of DNA lesions induced by ionizing radiation is mainly dependent on radiation quality, where the indirect action of radiation may contribute to different extent depending on the type of radiation under study. The effect of indirect action of radiation can be investigated by using agents that induce oxidative DNA damage or by applying free radical scavengers. The aim of this study was to investigate the role of the indirect effect of radiation for the repair fidelity of non-homologous end-joining (NHEJ), homologous recombination repair (HRR) and base excision repair (BER) when DNA damage of different complexity was induced by gamma radiation, alpha particles or from base damages (8-oxo-dG) induced by potassium bromate (KBrO{sub 3}). CHO cells lines deficient in XRCC3 (HRR) irs1SF, XRCC7 (NHEJ) V3-3 and XRCC1 (BER) EM9 were irradiated in the absence or presence of the free radical scavenger dimethyl sulfoxide (DMSO). The endpoints investigated included rate of cell proliferation by the DRAG assay, clonogenic cell survival and the level of primary DNA damage by the comet assay. The results revealed that the indirect effect of low-LET radiation significantly reduced the repair fidelity of both NHEJ and HRR pathways. For high-LET radiation the indirect effect of radiation also significantly reduced the repair fidelity for the repair deficient cell lines. The results suggest further that the repair fidelity of the error prone NHEJ repair pathway is more impaired by the indirect effect of high-LET radiation relative to the other repair pathways studied. The response to bromate observed for the two DSB repair deficient cell lines strongly support earlier studies that bromate induces complex DNA damages. The significantly reduced repair fidelity of irs1SF and V3-3 suggests that NHEJ as well as HRR are needed for the repair, and that complex DSBs are formed after bromate exposure.

  17. Viability in holder of irradiated cells: distinguish between repair and cell multiplication

    International Nuclear Information System (INIS)

    In experiments in which liquid holding recovery (LHR) was measured, the majority of cellular population is formed by non-viable cells and cell multiplication may be important for LHR expression. In order to distinguish between recuperation of viability (true LHR) and cell multiplication, it was necessary to employ improved plating techniques and a fluctuation test based on Poisson distribution. Our results are an indication that this fluctuation test, used together with the traditional method, is a good tool to distinguish repair from cell multiplication. (author)

  18. ESCRT III repairs nuclear envelope ruptures during cell migration to limit DNA damage and cell death.

    Science.gov (United States)

    Raab, M; Gentili, M; de Belly, H; Thiam, H R; Vargas, P; Jimenez, A J; Lautenschlaeger, F; Voituriez, Raphaël; Lennon-Duménil, A M; Manel, N; Piel, M

    2016-04-15

    In eukaryotic cells, the nuclear envelope separates the genomic DNA from the cytoplasmic space and regulates protein trafficking between the two compartments. This barrier is only transiently dissolved during mitosis. Here, we found that it also opened at high frequency in migrating mammalian cells during interphase, which allowed nuclear proteins to leak out and cytoplasmic proteins to leak in. This transient opening was caused by nuclear deformation and was rapidly repaired in an ESCRT (endosomal sorting complexes required for transport)-dependent manner. DNA double-strand breaks coincided with nuclear envelope opening events. As a consequence, survival of cells migrating through confining environments depended on efficient nuclear envelope and DNA repair machineries. Nuclear envelope opening in migrating leukocytes could have potentially important consequences for normal and pathological immune responses. PMID:27013426

  19. Treating hearing disorders with cell and gene therapy

    Science.gov (United States)

    Gillespie, Lisa N.; Richardson, Rachael T.; Nayagam, Bryony A.; Wise, Andrew K.

    2014-12-01

    Hearing loss is an increasing problem for a substantial number of people and, with an aging population, the incidence and severity of hearing loss will become more significant over time. There are very few therapies currently available to treat hearing loss, and so the development of new therapeutic strategies for hearing impaired individuals is of paramount importance to address this unmet clinical need. Most forms of hearing loss are progressive in nature and therefore an opportunity exists to develop novel therapeutic approaches to slow or halt hearing loss progression, or even repair or replace lost hearing function. Numerous emerging technologies have potential as therapeutic options. This paper details the potential of cell- and gene-based therapies to provide therapeutic agents to protect sensory and neural cells from various insults known to cause hearing loss; explores the potential of replacing lost sensory and nerve cells using gene and stem cell therapy; and describes the considerations for clinical translation and the challenges that need to be overcome.

  20. Stem cell therapy to treat heart ischaemia

    DEFF Research Database (Denmark)

    Qayyum, Abbas Ali; Mathiasen, Anders Bruun; Kastrup, Jens

    2014-01-01

    (CABG), morbidity and mortality is still high in patients with CAD. Along with PCI and CABG or in patients without options for revascularization, stem cell regenerative therapy in controlled trials is a possibility. Stem cells are believed to exert their actions by angiogenesis and regeneration of...... cardiomyocytes. Recently published clinical trials and meta-analysis of stem cell studies have shown encouraging results with increased left ventricle ejection fraction and reduced symptoms in patients with CAD and heart failure. There is some evidence of mesenchymal stem cell being more effective compared to...... other cell types and cell therapy may be more effective in patients with known diabetes mellitus. However, further investigations are warranted....

  1. Stem cell factor receptor induces progenitor and natural killer cell-mediated cardiac survival and repair after myocardial infarction

    OpenAIRE

    Ayach, Bilal B.; Yoshimitsu, Makoto; Dawood, Fayez; Sun, Mei; Arab, Sara; Chen, Manyin; HIGUCHI, KOJI; Siatskas, Christopher; Lee, Paul; Lim, Hilda; Zhang, Jane; Cukerman, Eva; Stanford, William L.; Medin, Jeffrey A; Liu, Peter P.

    2006-01-01

    Inappropriate cardiac remodeling and repair after myocardial infarction (MI) predisposes to heart failure. Studies have reported on the potential for lineage negative, steel factor positive (c-kit+) bone marrow-derived hematopoetic stem∕progenitor cells (HSPCs) to repair damaged myocardium through neovascularization and myogenesis. However, the precise contribution of the c-kit signaling pathway to the cardiac repair process has yet to be determined. In this study, we sought to directly eluci...

  2. Intramuscular injection of bone marrow mesenchymal stem cells with small gap neurorrhaphy for peripheral nerve repair.

    Science.gov (United States)

    Wang, Peiji; Zhang, Yong; Zhao, Jiaju; Jiang, Bo

    2015-01-12

    We had previously reported that small gap neurorrhaphy by scissoring and sleeve-jointing epineurium could enhance the rate and quality of peripheral nerve regeneration. To date, local implantation and systemic delivery of bone marrow mesenchymal stem cells (BMSCs) have been routinely used in nerve tissue engineering, but they each have some intrinsic limitations. We hypothesised that targeted muscular administration of BMSCs capable of reaching the damaged nerve would be advisable. Here, we investigated the therapeutic efficacy of transplantation of BMSCs through targeted muscular injection with small gap neurorrhaphy by scissoring and sleeve-jointing epineurium on repairing peripheral nerve injury in a rat model. One week after a rat model of peripheral nerve injury was established by small gap neurorrhaphy, thirty-six Sprague-Dawley rats were randomly divided into three groups (n=12): the intramuscular injection of BMSCs group (IM), the intravenous injection of BMSCs group (IV) and the intramuscular injection of phosphate-buffered solution group (PBS). The process of the nerve regeneration was assayed functionally and morphologically. The results indicated that compared to the IV-treated and PBS-treated groups, the targeted muscular injection therapy resulted in much more beneficial effects, as evidenced by increases in the sciatic function index, nerve conduction velocity, myelin sheath thickness and restoration rate of gastrocnemius muscle wet weight. In conclusion, the combination therapy of small gap neurorrhaphy and BMSC transplantation through targeted muscular injection can significantly promote the regeneration of peripheral nerve and improve the nerve's functional recovery, which may help establish a reliable approach for repairing peripheral nerve injury. PMID:25434870

  3. Pluripotent Stem Cells and Gene Therapy

    OpenAIRE

    Simara, Pavel; Motl, Jason A.; Kaufman, Dan S.

    2013-01-01

    Human pluripotent stem cells represent an accessible cell source for novel cell-based clinical research and therapies. With the realization of induced pluripotent stem cells (iPSCs), it is possible to produce almost any desired cell type from any patient's cells. Current developments in gene modification methods have opened the possibility for creating genetically corrected human iPSCs for certain genetic diseases that could be used later in autologous transplantation. Promising preclinical s...

  4. Dithiothreitol pretreatment and inducible repair in UV-irradiated Escherichia coli K12 cells

    International Nuclear Information System (INIS)

    The UV radiation survival of several Escherichia coli K12 strains was measured after pretreatment with dithiothreitol (DTT). In DNA repair-competent cells, UV survival was enhanced (ER = 1.2) after pretreating cells for 1.0h using 10 mmol dm-3 DTT and then incubating cells for 1.5h in buffer before UV irradiation. Similar experiments using the excision repair mutant, AB1886μυr A6, or the recombination repair and SOS-deficient mutant, AB2462recA, strains did not show enhanced UV survival. None of the E. coli strains tested were protected against UV killing by simultaneous treatment with DTT (10 mmol dm-3). These results, and the fact that incubation in chloramphenicol removed the wild-type response in DTT-pretreated, UV-irradiated cells, suggest that observed UV radioprotection was a result of inducible enzymatic repair processes such as recA-dependent repair. The proposed stimulus for inducible repair in these cells is DNA damage caused by intracellular hydroxyl radicals arising from thiol oxidation. The involvement of oxygen radicals in the induction pathway is supported by results that showed superoxide dismutase and catalase could inhibit a portion (one-third) of the inducible repair. (author)

  5. Early sensory re-education of the hand after peripheral nerve repair based on mirror therapy: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Mayara H. Paula

    2016-02-01

    Full Text Available BACKGROUND: Mirror therapy has been used as an alternative stimulus to feed the somatosensory cortex in an attempt to preserve hand cortical representation with better functional results. OBJECTIVE: To analyze the short-term functional outcome of an early re-education program using mirror therapy compared to a late classic sensory program for hand nerve repair. METHOD: This is a randomized controlled trial. We assessed 20 patients with median and ulnar nerve and flexor tendon repair using the Rosen Score combined with the DASH questionnaire. The early phase group using mirror therapy began on the first postoperative week and lasted 5 months. The control group received classic sensory re-education when the protective sensation threshold was restored. All participants received a patient education booklet and were submitted to the modified Duran protocol for flexor tendon repair. The assessments were performed by the same investigator blinded to the allocated treatment. Mann-Whitney Test and Effect Size using Cohen's d score were used for inter-group comparisons at 3 and 6 months after intervention. RESULTS: The primary outcome (Rosen score values for the Mirror Therapy group and classic therapy control group after 3 and 6 months were 1.68 (SD=0.5; 1.96 (SD=0.56 and 1.65 (SD=0.52; 1.51 (SD=0.62, respectively. No between-group differences were observed. CONCLUSION: Although some clinical improvement was observed, mirror therapy was not shown to be more effective than late sensory re-education in an intermediate phase of nerve repair in the hand. Replication is needed to confirm these findings.

  6. CD133+ cells contribute to radioresistance via altered regulation of DNA repair genes in human lung cancer cells

    International Nuclear Information System (INIS)

    Background: Radioresistance in human tumors has been linked in part to a subset of cells termed cancer stem cells (CSCs). The prominin 1 (CD133) cell surface protein is proposed to be a marker enriching for CSCs. We explore the importance of DNA repair in contributing to radioresistance in CD133+ lung cancer cells. Materials and methods: A549 and H1299 lung cancer cell lines were used. Sorted CD133+ cells were exposed to either single 4 Gy or 8 Gy doses and clonogenic survival measured. ϒ-H2AX immunofluorescence and quantitative real time PCR was performed on sorted CD133+ cells both in the absence of IR and after two single 4 Gy doses. Lentiviral shRNA was used to silence repair genes. Results: A549 but not H1299 cells expand their CD133+ population after single 4 Gy exposure, and isolated A549 CD133+ cells demonstrate IR resistance. This resistance corresponded with enhanced repair of DNA double strand breaks (DSBs) and upregulated expression of DSB repair genes in A549 cells. Prior IR exposure of two single 4 Gy doses resulted in acquired DNA repair upregulation and improved repair proficiency in both A549 and H1299. Finally Exo1 and Rad51 silencing in A549 cells abrogated the CD133+ IR expansion phenotype and induced IR sensitivity in sorted CD133+ cells. Conclusions: CD133 identifies a population of cells within specific tumor types containing altered expression of DNA repair genes that are inducible upon exposure to chemotherapy. This altered gene expression contributes to enhanced DSB resolution and the radioresistance phenotype of these cells. We also identify DNA repair genes which may serve as promising therapeutic targets to confer radiosensitivity to CSCs

  7. Human embryonic stem cells have enhanced repair of multiple forms of DNA damage

    DEFF Research Database (Denmark)

    Maynard, Scott; Swistowska, Anna Maria; Lee, Jae Wan;

    2008-01-01

    Embryonic stem cells need to maintain genomic integrity so that they can retain the ability to differentiate into multiple cell types without propagating DNA errors. Previous studies have suggested that mechanisms of genome surveillance, including DNA repair, are superior in mouse embryonic stem...... cells compared with various differentiated murine cells. Using single-cell gel electrophoresis (comet assay) we found that human embryonic stem cells (BG01, I6) have more efficient repair of different types of DNA damage (generated from H2O2, UV-C, ionizing radiation, or psoralen) than human primary...... fibroblasts (WI-38, hs27) and, with the exception of UV-C damage, HeLa cells. Microarray gene expression analysis showed that mRNA levels of several DNA repair genes are elevated in human embryonic stem cells compared with their differentiated forms (embryoid bodies). These data suggest that genomic...

  8. Differential repair of platinum-DNA adducts in human bladder and testicular tumor continuous cell lines

    International Nuclear Information System (INIS)

    The formation and removal of four platinum-DNA adducts were immunochemically quantitated in cultured cells derived from a human bladder carcinoma cell line (RT112) and from two lines derived from germ cell tumors of the testis (833K and SUSA), following exposure in vitro to 16.7 microM (5 micrograms/ml) cisplatin. RT112 cells were least sensitive to the drug and were proficient in the repair of all four adducts, whereas SUSA cells, which were 5-fold more sensitive, were deficient in the repair of DNA-DNA intrastrand cross-links in the sequences pApG and pGpG. Despite expressing a similar sensitivity to SUSA cells, 833K cells were proficient in the repair of all four adducts, although less so than the RT112 bladder tumor cells. In addition, SUSA cells were unable to repair DNA-DNA interstrand cross-links whereas 50-85% of these lesions were removed in RT112 and 833K cells 24 h following drug exposure. It is possible that the inability of SuSa cells to repair platinated DNA may account for their hypersensitivity to cisplatin

  9. Stem cell therapy for white matter disorders: don't forget the microenvironment!

    Science.gov (United States)

    Dooves, Stephanie; van der Knaap, Marjo S; Heine, Vivi M

    2016-07-01

    White matter disorders (WMDs) are a major source of handicap at all ages. They often lead to progressive neurological dysfunction and early death. Although causes are highly diverse, WMDs share the property that glia (astrocytes and oligodendrocytes) are among the cells primarily affected, and that myelin is either not formed or lost. Many WMDs might benefit from cell replacement therapies. Successful preclinical studies in rodent models have already led to the first clinical trials in humans using glial or oligodendrocyte progenitor cells aiming at (re)myelination. However, myelin is usually not the only affected structure. Neurons, microglia, and astrocytes are often also affected and are all important partners in creating the right conditions for proper white matter repair. Composition of the extracellular environment is another factor to be considered. Cell transplantation therapies might therefore require inclusion of non-oligodendroglial cell types and target more than only myelin repair. WMD patients would likely benefit from multimodal therapy approaches involving stem cell transplantation and microenvironment-targeting strategies to alter the local environment to a more favorable state for cell replacement. Furthermore most proof-of-concept studies have been performed with human cells in rodent disease models. Since human glial cells show a larger regenerative capacity than their mouse counterparts in the host mouse brain, microenvironmental factors affecting white matter recovery might be overlooked in rodent studies. We would like to stress that cell replacement therapy is a highly promising therapeutic option for WMDs, but a receptive microenvironment is crucial. PMID:27000179

  10. Two pathways of DNA double-strand break repair in G1 cells of Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    The G1 cells of the diploid yeast Saccharomyces cerevislae are known to be capable of a slow repair of DNA double-strand breaks (DSB) during holding the cells in a non-nutrient medium. In the present paper, it has been shown that S. cerevislae cells γ-irradiated in the G1 phase of cell cycle are capable of fast repair of DNA DSB; this process is completed within 30-40 min of holding the cells in water at 28 deg C. For this reason, the kinetics of DNA DSB repair during holding the cells in a non-nutrient medium are biphasic, i.e., the first, ''fast'' phase is completed within 30-40 min; wheras the second, ''slow'' one, within 48 h. Mutations rad51, rad52, rad54 and rad55 inhibit the fast repair of DNA DSB, whereas mutations rad50, rad53 and rad57 do not practically influence this process. It has been shown that the observed fast and slow repair of DNA DSB in the G1 diploid cells of S, cerevislae are separate pathways of DNA DSB repair in yeast

  11. A Novel Cell Death Gene Acts to Repair Patterning Defects in Drosophila melanogaster

    OpenAIRE

    Tanaka, Kentaro M.; Takahashi, Aya; Fuse, Naoyuki; Takano-Shimizu-Kouno, Toshiyuki

    2014-01-01

    Cell death is a mechanism utilized by organisms to eliminate excess cells during development. Here, we describe a novel regulator of caspase-independent cell death, Mabiki (Mabi), that is involved in the repair of the head patterning defects caused by extra copies of bicoid in Drosophila melanogaster. Mabiki functions together with caspase-dependent cell death mechanisms to provide robustness during development.

  12. The role of mismatch repair in small-cell lung cancer cells

    DEFF Research Database (Denmark)

    Hansen, L T; Thykjaer, T; Ørntoft, T F; Rasmussen, L J; Keller, P; Spang-Thomsen, M; Edmonston, T Bocker; Schmutte, C; Fishel, R; Petersen, L Nørgård

    2003-01-01

    The role of mismatch repair (MMR) in small-cell lung cancer (SCLC) is controversial, as the phenotype of a MMR-deficiency, microsatellite instability (MSI), has been reported to range from 0 to 76%. We studied the MMR pathway in a panel of 21 SCLC cell lines and observed a highly heterogeneous...... pattern of MMR gene expression. A significant correlation between the mRNA and protein levels was found. We demonstrate that low hMLH1 gene expression was not linked to promoter CpG methylation. One cell line (86MI) was found to be deficient in MMR and exhibited resistance to the alkylating agent MNNG...

  13. Introduction to Stem Cell Therapy

    OpenAIRE

    Biehl, Jesse K.; Russell, Brenda

    2009-01-01

    Stem cells have the ability to differentiate into specific cell types. The two defining characteristics of a stem cell are perpetual self-renewal and the ability to differentiate into a specialized adult cell type. There are two major classes of stem cells: pluripotent that can become any cell in the adult body, and multipotent that are restricted to becoming a more limited population of cells. Cell sources, characteristics, differentiation and therapeutic applications are discussed. Stem cel...

  14. Ultraviolet light-resistant primary transfectants of xeroderma pigmentosum cells are also DNA repair-proficient

    International Nuclear Information System (INIS)

    In a previous work, an immortal xeroderma pigmentosum cell line belonging to complementation group C was complemented to a UV-resistant phenotype by transfection with a human cDNA clone library. We now report that the primary transformants selected for UV-resistance also acquired normal levels of DNA repair. This was assessed both by measurement of UV-induced [3H]thymidine incorporation and by equilibrium sedimentation analysis of repair-DNA synthesis. Therefore, the transduced DNA element which confers normal UV-resistance also corrects the excision repair defect of the xeroderma pigmentosum group C cell line

  15. DNA strand breakage repair in ataxia telangiectasia fibroblast-like cells

    International Nuclear Information System (INIS)

    Human diploid fibroblast-like cells derived from four patients with the genetic disease ataxia telangiectasia and from two non-mutant donors were examined for the repair of X-ray induced strand breaks in DNA. The ataxia telangiectasia cultures showed no significant differences from the non-mutant cultures in the kinetics and extent of strand repair. This suggests that the increased spontaneous and X-ray induced chromatid aberrations observed in ataxia telangiectasia cells are not caused by a defect in the repair of single strand breaks as might be suspected from a general model of aberration production

  16. Recent progress with the DNA repair mutants of Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    Repair deficient mutants of Chinese hamster ovary (CHO) cells are being used to identify human genes that correct the repair defects and to study mechanisms of DNA repair and mutagenesis. Five independent tertiary DNA transformants were obtained from the EM9 mutant. In these clones a human DNA sequence was identified that correlated with the resistance of the cells to CldUrd. After Eco RI digestion, Southern transfer, and hybridization of transformant DNAs with the BLUR-8 Alu family sequence, a common fragment of 25 to 30 kb was present. 37 refs., 4 figs., 3 tabs

  17. Modeling of induced mutation process in bacterial cells with defects in excision repair system

    International Nuclear Information System (INIS)

    A mathematical model of the UV-induced mutation process in Escherichia coli bacteria cells with defects in uvrA and polA genes has been developed. The model describes in detail the reaction kinetics for excision repair system. The number of mismatches as results from translesion-synthesis is calculated for both wild-type and mutant cells. An effect of temporal modulation for amount of single-stranded DNA during post-replication repair is predicted. A comparison of repair system efficiency is conducted

  18. Trans-splicing repair of mutant p53 suppresses the growth of hepatocellular carcinoma cells in vitro and in vivo

    OpenAIRE

    Xingxing He; Fang Liu; Jingjun Yan; Yunan Zhang; Junwei Yan; Haitao Shang; Qian Dou; Qiu Zhao; Yuhu Song

    2015-01-01

    Reactivation of wild-type p53 (wt-p53) function is an attractive therapeutic approach to p53-defective cancers. An ideal p53-based gene therapy should restore wt-p53 production and reduces mutant p53 transcripts simultaneously. In this study, we described an alternative strategy named as trans-splicing that repaired mutant p53 transcripts in hepatocellular carcinoma (HCC) cells. The plasmids which encoded a pre-trans-splicing molecule (PTM) targeting intron 6 of p53 were constructed and then ...

  19. Propofol promotes spinal cord injury repair by bone marrow mesenchymal stem cell transplantation

    OpenAIRE

    Ya-jing Zhou; Jian-min Liu; Shu-ming Wei; Yun-hao Zhang; Zhen-hua Qu; Shu-bo Chen

    2015-01-01

    Propofol is a neuroprotective anesthetic. Whether propofol can promote spinal cord injury repair by bone marrow mesenchymal stem cells remains poorly understood. We used rats to investigate spinal cord injury repair using bone marrow mesenchymal stem cell transplantation combined with propofol administration via the tail vein. Rat spinal cord injury was clearly alleviated; a large number of newborn non-myelinated and myelinated nerve fibers appeared in the spinal cord, the numbers of CM-Dil-l...

  20. Formaldehyde catabolism is essential in cells deficient for the Fanconi anemia DNA-repair pathway.

    Science.gov (United States)

    Rosado, Ivan V; Langevin, Frédéric; Crossan, Gerry P; Takata, Minoru; Patel, Ketan J

    2011-12-01

    Metabolism is predicted to generate formaldehyde, a toxic, simple, reactive aldehyde that can damage DNA. Here we report a synthetic lethal interaction in avian cells between ADH5, encoding the main formaldehyde-detoxifying enzyme, and the Fanconi anemia (FA) DNA-repair pathway. These results define a fundamental role for the combined action of formaldehyde catabolism and DNA cross-link repair in vertebrate cell survival. PMID:22081012

  1. The Endocrine Regulation of Stem Cells: Physiological Importance and Pharmacological Potentials for Cell-Based Therapy.

    Science.gov (United States)

    Ghorbani, Ahmad; Naderi-Meshkin, Hojjat

    2016-01-01

    Throughout life, different types of stem cells participate in tissue generation, maintenance, plasticity, and repair. Their abilities to secrete growth factors, to proliferate and differentiate into several cell lineages, and to migrate and home into the damaged tissues have made them attractive candidates for cell therapy and tissue engineering applications. Normal stem cell function is tied to the cell-intrinsic mechanisms and extrinsic signals derived from the surrounding microenvironment or circulation. Understanding the regulatory signals that govern stem cell functions is essential in order to have full knowledge about organogenesis, tissue maintenance and tissue plasticity in the physiological condition. It is also important for optimizing tissue engineering and improving the therapeutic efficiency of stem cells in regenerative medicine. A growing body of evidence indicates that hormonal signals can critically influence stem cell functions in fetal, postnatal, and adult tissues. This review focuses on recent studies revealing how growth hormone, insulin, thyroid hormone, parathormone, adrenocorticotropin, glucocorticoids, erythropoietin, and gastrointestinal hormones control stem cell behavior through influencing survival, proliferation, migration, homing, and differentiation of these cells. Moreover, how environmental factors such as exercise, hypoxia, and nutrition might affect stem cell functions through influencing the endocrine system is discussed. Some of the current limitations of cell therapy and how hormones can help overcoming these limitations are briefly outlined. PMID:26337380

  2. Percutaneous Mitral Valve Repair in Mitral Regurgitation Reduces Cell-Free Hemoglobin and Improves Endothelial Function.

    Directory of Open Access Journals (Sweden)

    Christos Rammos

    Full Text Available Endothelial dysfunction is predictive for cardiovascular events and may be caused by decreased bioavailability of nitric oxide (NO. NO is scavenged by cell-free hemoglobin with reduction of bioavailable NO up to 70% subsequently deteriorating vascular function. While patients with mitral regurgitation (MR suffer from an impaired prognosis, mechanisms relating to coexistent vascular dysfunctions have not been described yet. Therapy of MR using a percutaneous mitral valve repair (PMVR approach has been shown to lead to significant clinical benefits. We here sought to investigate the role of endothelial function in MR and the potential impact of PMVR.Twenty-seven patients with moderate-to-severe MR treated with the MitraClip® device were enrolled in an open-label single-center observational study. Patients underwent clinical assessment, conventional echocardiography, and determination of endothelial function by measuring flow-mediated dilation (FMD of the brachial artery using high-resolution ultrasound at baseline and at 3-month follow-up. Patients with MR demonstrated decompartmentalized hemoglobin and reduced endothelial function (cell-free plasma hemoglobin in heme 28.9±3.8 μM, FMD 3.9±0.9%. Three months post-procedure, PMVR improved ejection fraction (from 41±3% to 46±3%, p = 0.03 and NYHA functional class (from 3.0±0.1 to 1.9±1.7, p<0.001. PMVR was associated with a decrease in cell free plasma hemoglobin (22.3±2.4 μM, p = 0.02 and improved endothelial functions (FMD 4.8±1.0%, p<0.0001.We demonstrate here that plasma from patients with MR contains significant amounts of cell-free hemoglobin, which is accompanied by endothelial dysfunction. PMVR therapy is associated with an improved hemoglobin decompartmentalization and vascular function.

  3. Low Reactive Level Laser Therapy for Mesenchymal Stromal Cells Therapies

    Directory of Open Access Journals (Sweden)

    Toshihiro Kushibiki

    2015-01-01

    Full Text Available Low reactive level laser therapy (LLLT is mainly focused on the activation of intracellular or extracellular chromophore and the initiation of cellular signaling by using low power lasers. Over the past forty years, it was realized that the laser therapy had the potential to improve wound healing and reduce pain and inflammation. In recent years, the term LLLT has become widely recognized in the field of regenerative medicine. In this review, we will describe the mechanisms of action of LLLT at a cellular level and introduce the application to mesenchymal stem cells and mesenchymal stromal cells (MSCs therapies. Finally, our recent research results that LLLT enhanced the MSCs differentiation to osteoblast will also be described.

  4. Stem cell therapy. Use of differentiated pluripotent stem cells as replacement therapy for treating disease

    DEFF Research Database (Denmark)

    Fox, Ira J; Daley, George Q; Goldman, Steven A;

    2014-01-01

    Pluripotent stem cells (PSCs) directed to various cell fates holds promise as source material for treating numerous disorders. The availability of precisely differentiated PSC-derived cells will dramatically affect blood component and hematopoietic stem cell therapies and should facilitate......, and industry is critical for generating new stem cell-based therapies....... treatment of diabetes, some forms of liver disease and neurologic disorders, retinal diseases, and possibly heart disease. Although an unlimited supply of specific cell types is needed, other barriers must be overcome. This review of the state of cell therapies highlights important challenges. Successful...

  5. Repair of DNA strand breaks in progeric fibroblasts and aging human diploid cells

    International Nuclear Information System (INIS)

    The rate of rejoining of DNA strand breaks induced by 10 krad of γ-irradiation has been studied in normal human diploid skin fibroblasts and skin fibroblasts from six patients with symptoms of progeria. Although slightly more rapid in very early passage, the repair rate in normal cells was similar throughout most of their life span in vitro. The appearance of cells with reduced repair capacity was evident as the cultures became senescent. The progeric fibroblasts varied greatly in their response to irradiation. The rate of repair was greatly reduced in two strains, whereas in two others extensive DNA degradation was consistently observed in unirradiated cells. Degradation was apparently related to the radiation received from the incorporated radiolabel. Normal repair was seen in progeric fibroblasts transformed by SV40 virus

  6. Time effectiveness of DNA injury and its repair induced by irradiation using single cell gel electrophoresis

    International Nuclear Information System (INIS)

    Objective: To improve the accuracy of estimation of radiation biodosimetry after radiation accident, to explore the time-effect relationship of DNA repair after irradiation, and to describe the curves and plane of DNA repair. Methods: The neutral single cell gel electrophoresis (SCGE) was performed to estimate the repair of DNA double-strand break (DNA-DSB) in human lymphocytes induced by different dose of radiation at 3, 24, 48, 72 h post irradiation. Results: Better goodness of fit was obtained not only in the dose-response curves at different time points, but also in the time-response curves at different doses. A smooth three-dimensional plane model was obtained when combining the two curves. Conclusions: The curves of DNA-DSB repair showed a linear relationship, and repair of radiation-plane model could be used for biological dosimetry. (authors)

  7. Nucleotide-excision repair of DNA in cell-free extracts of the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    A wide spectrum of DNA lesions are repaired by the nucleotide-excision repair (NER) pathway in both eukaryotic and prokaryotic cells. We have developed a cell-free system in Saccharomyces cerevisiae that supports NER. NER was monitored by measuring repair synthesis in DNA treated with cisplatin or with UV radiation. Repair synthesis in vitro was defective in extracts of rad1, rad2, and rad10 mutant cells, all of which have mutations in genes whose products are known to be required for NER in vivo. Additionally, repair synthesis was complemented by mixing different mutant extracts, or by adding purified Rad1 or Rad10 protein to rad1 or rad10 mutant extracts, respectively. The latter observation demonstrates that the Rad1 and Rad10 proteins directly participate in the biochemical pathway of NER. NER supported by nuclear extracts requires ATP and Mg2+ and is stimulated by polyethylene glycol and by small amounts of whole cell extract containing overexpressed Rad2 protein. The nuclear extracts also contain base-excision repair activity that is present at wild-type levels in rad mutant extracts. This cell-free system is expected to facilitate studies on the biochemical pathway of NER in S. cerevisiae

  8. [Outlook: Future therapy of renal cell carcinoma].

    Science.gov (United States)

    Bergmann, Lothar; Miller, Kurt

    2010-01-01

    Targeted therapies have fundamentally altered the therapy of metastatic renal cell carcinoma (mRCC). Sunitinib today is an internationally recommended reference standard in first-line therapy; other drugs such as Temsirolimus, Everolimus, Bevacizumab (in combination with Interferon-alpha) and Sorafenib are part of the therapeutic arsenal. Practitioners thus have now more and better therapeutic options at hand, leading to a significantly improved prognosis for mRCC patients. Numerous ongoing research activities aim at the improvement of the benefits of the new compounds in the metastatic situation or application earlier in the course of the disease. Key aspects of future development in RCC are the optimization of the current therapy options by developing new targeted therapies, the search for the best combinations and sequences including the role of nephrectomy and the assessment in the adjuvant or neo-adjuvant setting. The following contribution provides an overview of ongoing studies, thus giving insight into the future therapy of RCC. PMID:20164673

  9. Effects of trypsin on X-ray-induced cell killing, chromosome abnormalities and kinetics of DNA repair in mammalian cells

    International Nuclear Information System (INIS)

    When cells are trypsinized before irradiation a potentiation of X-ray damage may occur. This is known as the 'trypsin effect'. Potentiation of X-ray damage on cell killing was seen in V79 Chinese hamster cells but was marginal in Chinese hamster ovary (CHO K1) cells and not evident in murine Ehrlich ascites tumour (EAT) cells. Trypsinization did however increase the number of X-ray-induced chromosomal abnormalities in all 3 lines. To investigate the possibility that trypsin acts by digestion of proteins in chromatin, further experiments were performed to monitor DNA damage and repair. Induction of DNA breaks by X-rays was unaffected by trypsin but trypsinized EAT (suspension) cells repaired single-strand breaks (sbb) less rapidly than controls indicating an inhibitory effect or trypsin on ssb repair. However double-strand break (dsb) repair was unaffected by trypsin. It was also found that the EDTA solution in which the trypsin was dissolved also contributes to the inhibition of dsb repair. The results show that trypsinization can enhance X-ray-induced cell killing, chromosomal damage and DNA repair, the effect varying between cell lines. (author). 37 refs.; 7 figs

  10. Light-emitting diode therapy increases collagen deposition during the repair process of skeletal muscle.

    Science.gov (United States)

    de Melo, Claudia Aparecida Viana; Alves, Agnelo Neves; Terena, Stella Maris Lins; Fernandes, Kristianne Porta Santos; Nunes, Fábio Daumas; da Silva, Daniela de Fátima Teixeira; Bussadori, Sandra Kalil; Deana, Alessandro Melo; Mesquita-Ferrari, Raquel Agnelli

    2016-04-01

    This study analyzed the effects of light-emitting diode (LED) therapy on the morphology of muscle tissue as well as collagen remodeling and matrix metalloproteinase 2 (MMP-2) activity in the skeletal muscle of rats following acute injury. Wistar rats were divided into four groups: (1) control, (2) sham, (3) untreated cryoinjury, and (4) cryoinjury treated with LED. Cryoinjury was induced by two applications of a metal probe cooled in liquid nitrogen directly onto the belly of the tibialis anterior muscle. For treatment, the LED equipment (wavelength 850 nm, output power 30 mW, and total energy 3.2 J) was used daily. The study periods were 1, 3, and 7 days after cryoinjury. Morphological aspects were evaluated through hematoxylin-eosin staining. The amount of collagen fibers was evaluated using Picro Sirius Red staining under polarized light. The gelatinase activity of MMP-2 was evaluated using zymography. The results showed significant reductions in inflammatory infiltrate after 3 days and an increased number of immature muscle fibers after 7 days. Furthermore, treatment induced a reduction in the gelatinolytic activity of MMP-2 after 1, 3, and 7 days in comparison to the untreated injury groups and increased the collagen deposition after 3 and 7 days in the treated groups. LED therapy at 850 nm induced a significant reduction in inflammation, decreased MMP-2 activity, and increased the amount of immature muscle and collagen fibers during the muscle repair process following acute injury. PMID:26873500

  11. Enhancement of DNA repair capacity of mammalian cells by carcinogen treatment

    International Nuclear Information System (INIS)

    To determine whether DNA excision repair is enhanced in mammalian cells in response to DNA damage, as it is in bacteria as part of the SOS response, we used an expression vector-host cell reactivation assay to measure cellular DNA repair capacity. When UV-damaged chloramphenicol acetyltransferase (CAT) vector DNA was introduced into monkey cells (CV-1), the level of CAT activity was inversely related to the UV fluence due to inhibition of CAT gene expression by UV photoproducts. When CV-1 cells were treated with either UV radiation or mitomycin C, 24-48 h before transfection, CAT expression from the UV-irradiated plasmid was increased. This increase also occurred in a line of normal human cells, but not in repair-deficient human xeroderma pigmentosum cells. We confirmed that this increase in CAT expression was due to repair, and not to production of damage-free templates by recombination; the frequency of generation of supF+ recombinants after transfection with UV-irradiated pZ189 vectors carrying different point mutations in the supF gene did not significantly increase in carcinogen-treated CV-1 cells. From these results we conclude that carcinogen treatment enhances the excision-repair capacity of normal mammalian cells

  12. Pluripotent Stem Cells and Gene Therapy

    Science.gov (United States)

    Simara, Pavel; Motl, Jason A.; Kaufman, Dan S.

    2013-01-01

    Human pluripotent stem cells represent an accessible cell source for novel cell-based clinical research and therapies. With the realization of induced pluripotent stem cells (iPSCs), it is possible to produce almost any desired cell type from any patient's cells. Current developments in gene modification methods have opened the possibility for creating genetically corrected human iPSCs for certain genetic diseases that could be used later in autologous transplantation. Promising preclinical studies have demonstrated correction of disease-causing mutations in a number of hematological, neuronal and muscular disorders. This review aims to summarize these recent advances with a focus on iPSC generation techniques, as well as gene modification methods. We will then further discuss some of the main obstacles remaining to be overcome before successful application of human pluripotent stem cell-based therapy arrives in the clinic and what the future of stem cell research may look like. PMID:23353080

  13. Translational research of adult stem cell therapy

    Institute of Scientific and Technical Information of China (English)

    Gen; Suzuki

    2015-01-01

    Congestive heart failure(CHF) secondary to chronic coronary artery disease is a major cause of morbidity and mortality world-wide. Its prevalence is increasing despite advances in medical and device therapies. Cell based therapies generating new cardiomyocytes and vessels have emerged as a promising treatment to reverse functional deterioration and prevent the progression to CHF. Functional efficacy of progenitor cells isolated from the bone marrow and the heart have been evaluated in preclinical large animal models. Furthermore, several clinical trials using autologous and allogeneic stem cells and progenitor cells have demonstrated their safety in humans yet their clinical relevance is inconclusive. This review will discuss the clinical therapeutic applications of three specific adult stem cells that have shown particularly promising regenerative effects in preclinical studies, bone marrow derived mesenchymal stem cell, heart derived cardiosphere-derived cell and cardiac stem cell. We will also discuss future therapeutic approaches.

  14. Human amniotic fluid stem cells labeled with up-conversion nanoparticles for imaging-monitored repairing of acute lung injury.

    Science.gov (United States)

    Xu, Yunyun; Xiang, Jian; Zhao, He; Liang, Hansi; Huang, Jie; Li, Yan; Pan, Jian; Zhou, Huiting; Zhang, Xueguang; Wang, Jiang Huai; Liu, Zhuang; Wang, Jian

    2016-09-01

    Human amniotic fluid stem (hAFS) cells have generated a great deal of excitement in cell-based therapies and regenerative medicine. Here, we examined the effect of hAFS cells labeled with dual-polymer-coated UCNP-PEG-PEI nanoparticles in a murine model of acute lung injury (ALI). We observed hAFS cells migration to the lung using highly sensitive in vivo upconversion luminescence (UCL) imaging. We demonstrated that hAFS cells remained viable and retained their ability to differentiate even after UCNP-PEG-PEI labeling. More importantly, hAFS cells displayed remarkable positive effects on ALI-damaged lung tissue repair compared with mouse bone marrow mesenchymal stem cells (mBMSCs), which include recovery of the integrity of alveolar-capillary membrane, attenuation of transepithelial leukocyte and neutrophil migration, and down-regulation of proinflammatory cytokine and chemokine expression. Our work highlights a promising role for imaging-guided hAFS cell-based therapy in ALI. PMID:27244692

  15. Recent insights: mesenchymal stromal/stem cell therapy for acute respiratory distress syndrome

    Science.gov (United States)

    Horie, Shahd; Laffey, John G.

    2016-01-01

    Acute respiratory distress syndrome (ARDS) causes respiratory failure, which is associated with severe inflammation and lung damage and has a high mortality and for which there is no therapy. Mesenchymal stromal/stem cells (MSCs) are adult multi-progenitor cells that can modulate the immune response and enhance repair of damaged tissue and thus may provide a therapeutic option for ARDS. MSCs demonstrate efficacy in diverse in vivo models of ARDS, decreasing bacterial pneumonia and ischemia-reperfusion-induced injury while enhancing repair following ventilator-induced lung injury. MSCs reduce the pro-inflammatory response to injury while augmenting the host response to bacterial infection. MSCs appear to exert their effects via multiple mechanisms—some are cell interaction dependent whereas others are paracrine dependent resulting from both soluble secreted products and microvesicles/exosomes derived from the cells. Strategies to further enhance the efficacy of MSCs, such as by overexpressing anti-inflammatory or pro-repair molecules, are also being investigated. Encouragingly, early phase clinical trials of MSCs in patients with ARDS are under way, and experience with these cells in trials for other diseases suggests that the cells are well tolerated. Although considerable translational challenges, such as concerns regarding cell manufacture scale-up and issues regarding cell potency and batch variability, must be overcome, MSCs constitute a highly promising potential therapy for ARDS.

  16. Inactivation of ultraviolet repair in normal and xeroderma pigmentosum cells by methyl methanesulfonate

    International Nuclear Information System (INIS)

    Excision repair of ultraviolet damage in the DNA of normal and xeroderma pigmentosum (Groups C, D, and variant) cells was inactivated by exposure of cells to methyl methanesulfonate immediately before irradiation independent of the presence of 0 to 10% fetal calf serum. The inactivation could be represented by a semilog relationship between the amount of repair and methyl methanesulfonate concentration up to approximately 5 mM. The inactivation can be considered to occur as the result of alkylation of a large (about 10(6) daltons) repair enzyme complex, and the dose required to reduce repair to 37% for most cells types was between 4 and 7 mM. No consistent, large difference in sensitivity to methyl methanesulfonate was found in any xeroderma pigmentosum complementation group compared to normal cells, implying that reduced repair in these groups may be caused by small inherited changes in the amino acid composition (i.e., point mutations or small deletions) rather than by losses of major components of the repair enzyme complex

  17. Characterization of DNA repair phenotypes of Xeroderma pigmentosum cell lines by a paralleled in vitro test

    International Nuclear Information System (INIS)

    DNA is constantly damaged modifying the genetic information for which it encodes. Several cellular mechanisms as the Base Excision Repair (BER) and the Nucleotide Excision Repair (NER) allow recovering the right DNA sequence. The Xeroderma pigmentosum is a disease characterised by a deficiency in the NER pathway. The aim of this study was to propose an efficient and fast test for the diagnosis of this disease as an alternative to the currently available UDS test. DNA repair activities of XP cell lines were quantified using in vitro miniaturized and paralleled tests in order to establish DNA repair phenotypes of XPA and XPC deficient cells. The main advantage of the tests used in this study is the simultaneous measurement of excision or excision synthesis (ES) of several lesions by only one cellular extract. We showed on one hand that the relative ES of the different lesions depend strongly on the protein concentration of the nuclear extract tested. Working at high protein concentration allowed discriminating the XP phenotype versus the control one, whereas it was impossible under a certain concentration's threshold. On the other hand, while the UVB irradiation of control cells stimulated their repair activities, this effect was not observed in XP cells. This study brings new information on the XPA and XPC protein roles during BER and NER and underlines the complexity of the regulations of DNA repair processes. (author)

  18. Induction and repair of DNA strand breaks in human tumor cells

    International Nuclear Information System (INIS)

    The presence of radioresistant or repair-proficient cells in a tumor is often associated with radiotherapy failure. The authors have begun to study the mechanisms of resistance in these tumor cells. Their initial studies focused on the induction and repair of DNA strand breaks as measured by DNA elution. Eight human tumor (5 squamous cell carcinomas, 2 melanomas, and 1 adenocarcinoma) and 2 nonmalignant cell lines have been examined. Their D/sub O/s range from 1.07 Gy to 2.81 Gy while their extrapolation numbers (n) range from 1.2 to 24.8. Three parameters are being investigated for X-ray-induced DNA single and double-strand breaks; 1) the initial number of breaks induced, 2) the residual DNA strand break frequency and 3) the time to repair 50% of the lesions. The kinetics of repair of DNA single-strand breaks were similar for all the lines studied. In 2 cases, radiosensitivity was associated with either a high residual DNA strand break frequency or a slower rate of repair. No single parameter or combination of parameters, however, consistently correlated with radiosensitivity or n. Thus, while differences in the induction and repair of DNA single-strand breaks might explain some of the observed differences in radiation responses, they are in general a poor predictor radiation sensitivity

  19. Deficient repair of potentially lethal damage in actively growing ataxia telangiectasia cells

    International Nuclear Information System (INIS)

    The repair of potentially lethal damage after X rays was studied in exponentially growing normal and ataxia telangiectasia (A-T) strains of human fibroblasts. X-ray killing of all normal strains from six healthy persons was enhanced when cells were treated with hypertonic phosphate-buffered saline immediately after irradiation. This treatment is not toxic to unirradiated cells and demonstrates that ordinarily these cells repair potentially lethal damage. The potentially lethal damage in normal cells is repaired within 1 hr. In contrast, all A-T strains from four A-T patients were completely deficient in their ability to repair potentially lethal damage. Treatment with a hypertonic solution after X irradiation is known to increase the frequency of chromosomal aberrations and to enhance cell killing, as though hypertonicity had induced the A-T state in normal cells. These results support the inference that the increased radiosensitivity of A-T cells can be attributed to some defect in the repair of DNA damage rather than abnormal DNA synthesis following irradiation

  20. Genetic characterization of cells of homocystinuria patients with disrupted DNA repair system

    International Nuclear Information System (INIS)

    Fibroblasts obtained from biopsy material and lymphocytes of patients with homocystinuria were investigated for repair activity according to the following criteria: rejoined DNA breaks, induced by 4-nitroquinoline-1-oxide and γ-radiation; indices of reactivation and induced mutagenesis of smallpox vaccine virus treated with these mutagens. In lymphocytes a defect of DNA repair was observed according to all criteria investigated. During passage of fibroblast cultures, inhibition of repair activity of cells was preserved according to γ-type. Increase in the number of spontaneous and γ-induced mutations of virus was noted according to degree of passage of fibroblasts

  1. Association between age and repair of oxidatively damaged DNA in human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Løhr, Mille; Jensen, Annie; Eriksen, Louise;

    2015-01-01

    damaged DNA in peripheral blood mononuclear cells (PBMCs). We isolated PBMCs from subjects aged 18-83 years, as part of a health survey of the Danish population that focussed on lifestyle factors. The level of DNA repair activity was measured as incisions on potassium bromate-damaged DNA by the comet...... assay. There was an inverse association between age and DNA repair activity with a 0.65% decline in activity per year from age 18 to 83 (95% confidence interval: 0.16-1.14% per year). Univariate regression analysis also indicated inverse associations between DNA repair activity and waist-hip ratio (P...

  2. The cell-cycle checkpoint kinase Chk1 is required for mammalian homologous recombination repair

    DEFF Research Database (Denmark)

    Sørensen, Claus Storgaard; Hansen, Lasse Tengbjerg; Dziegielewski, Jaroslaw;

    2005-01-01

    The essential checkpoint kinase Chk1 is required for cell-cycle delays after DNA damage or blocked DNA replication. However, it is unclear whether Chk1 is involved in the repair of damaged DNA. Here we establish that Chk1 is a key regulator of genome maintenance by the homologous recombination......, the essential recombination repair protein RAD51 is recruited to DNA repair foci performing a vital role in correct HRR. We demonstrate that Chk1 interacts with RAD51, and that RAD51 is phosphorylated on Thr 309 in a Chk1-dependent manner. Consistent with a functional interplay between Chk1 and RAD51...

  3. Formation and repair of γ-radiation induced DNA breaks in micrococcus radiodurans cells

    International Nuclear Information System (INIS)

    A study was made of the yield of single- and double-strand DNA breaks in γ-irradiated M. radiodurans cells. It was shown that the system of superfast and fast repair of single-strand breaks of the studied bacteria is more effective than that of E.coli. The two studied strains of M. radiodurans differing in radiosensitivity exhibited similar effectiveness of the superfast and fast repair of single-strand breaks but the radioresistant strain possessed a better capacity for postirradiation repair of doublestrand breaks than the radiosensitive strain

  4. Nrf2 facilitates repair of radiation induced DNA damage through homologous recombination repair pathway in a ROS independent manner in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, Sundarraj; Pal, Debojyoti; Sandur, Santosh K., E-mail: sskumar@barc.gov.in

    2015-09-15

    Highlights: • Nrf2 inhibition in A549 cells led to attenuated DNA repair and radiosensitization. • Influence of Nrf2 on DNA repair is not linked to its antioxidant function. • Nrf2 influences DNA repair through homologous recombination (HR) repair pathway. • Many genes involved in HR pathway show ARE sequences in their upstream region. - Abstract: Nrf2 is a redox sensitive transcription factor that is involved in the co-ordinated transcription of genes involved in redox homeostasis. But the role of Nrf2 in DNA repair is not investigated in detail. We have employed A549 and MCF7 cells to study the role of Nrf2 on DNA repair by inhibiting Nrf2 using all-trans retinoic acid (ATRA) or by knock down approach prior to radiation exposure (4 Gy). DNA damage and repair analysis was studied by γH2AX foci formation and comet assay. Results suggested that the inhibition of Nrf2 in A549 or MCF7 cells led to significant slowdown in DNA repair as compared to respective radiation controls. The persistence of residual DNA damage even in the presence of free radical scavenger N-acetyl cysteine, suggested that the influence of Nrf2 on DNA repair was not linked to its antioxidant functions. Further, its influence on non-homologous end joining repair pathway was studied by inhibiting both Nrf2 and DNA-PK together. This led to synergistic reduction of survival fraction, indicating that Nrf2 may not be influencing the NHEJ pathway. To investigate the role of homologous recombination repair (HR) pathway, RAD51 foci formation was monitored. There was a significant reduction in the foci formation in cells treated with ATRA or shRNA against Nrf2 as compared to their respective radiation controls. Further, Nrf2 inhibition led to significant reduction in mRNA levels of RAD51. BLAST analysis was also performed on upstream regions of DNA repair genes to identify antioxidant response element and found that many repair genes that are involved in HR pathway may be regulated by Nrf2

  5. Nrf2 facilitates repair of radiation induced DNA damage through homologous recombination repair pathway in a ROS independent manner in cancer cells

    International Nuclear Information System (INIS)

    Highlights: • Nrf2 inhibition in A549 cells led to attenuated DNA repair and radiosensitization. • Influence of Nrf2 on DNA repair is not linked to its antioxidant function. • Nrf2 influences DNA repair through homologous recombination (HR) repair pathway. • Many genes involved in HR pathway show ARE sequences in their upstream region. - Abstract: Nrf2 is a redox sensitive transcription factor that is involved in the co-ordinated transcription of genes involved in redox homeostasis. But the role of Nrf2 in DNA repair is not investigated in detail. We have employed A549 and MCF7 cells to study the role of Nrf2 on DNA repair by inhibiting Nrf2 using all-trans retinoic acid (ATRA) or by knock down approach prior to radiation exposure (4 Gy). DNA damage and repair analysis was studied by γH2AX foci formation and comet assay. Results suggested that the inhibition of Nrf2 in A549 or MCF7 cells led to significant slowdown in DNA repair as compared to respective radiation controls. The persistence of residual DNA damage even in the presence of free radical scavenger N-acetyl cysteine, suggested that the influence of Nrf2 on DNA repair was not linked to its antioxidant functions. Further, its influence on non-homologous end joining repair pathway was studied by inhibiting both Nrf2 and DNA-PK together. This led to synergistic reduction of survival fraction, indicating that Nrf2 may not be influencing the NHEJ pathway. To investigate the role of homologous recombination repair (HR) pathway, RAD51 foci formation was monitored. There was a significant reduction in the foci formation in cells treated with ATRA or shRNA against Nrf2 as compared to their respective radiation controls. Further, Nrf2 inhibition led to significant reduction in mRNA levels of RAD51. BLAST analysis was also performed on upstream regions of DNA repair genes to identify antioxidant response element and found that many repair genes that are involved in HR pathway may be regulated by Nrf2

  6. Repair and cell cycle response in cells exposed to environmental biohazards. Final report, January 1, 1973-December 31, 1984

    International Nuclear Information System (INIS)

    These studies have focussed on agents which cause damage to DNA leading to inhibition of DNA synthesis or faulty DNA replication or repair. The overall goal of this project has been to understand how environmental agents interact with the DNA of cells and how cells cope with any resulting damage. In particular we have been concerned with the nature of the repair systems involved in restoration of damaged DNA and the cellular responses to radiation or chemical damage

  7. Immunohistochemical characteristics of epithelial cell rests of Malassez during cementum repair.

    Science.gov (United States)

    Hasegawa, Naohiko; Kawaguchi, Hiroyuki; Ogawa, Tetsuji; Uchida, Takashi; Kurihara, Hidemi

    2003-02-01

    To clarify the roles of epithelial cell rests of Malassez (ECRM) during periodontal repair, experimental root resorption was induced in rats and then the ECRM that existed in periodontal ligament during cementum repair was investigated using morphological and immunohistochemical approaches. At day 7, after mechanical injury, root resorption was observed and ECRM were present adjacent to the site of resorption lacunae. They were observed in periodontal ligament adjacent to site of the resorption lacunae. These ECRM were immunoreactive for bone morphogenetic protein-2. During the stage of early cementum repair, the ECRM were immunoreactive for osteopontin and ameloblastin. They strongly reacted to proliferating cell nuclear antigen. In uninjured control sections, ECRM located in the periodontal ligament adjacent to cementum were not immunoreactive for any antibodies. These findings suggested that ECRM may be related to cementum repair by activating their potential to secrete matrix proteins which have been expressed in tooth development. PMID:12558937

  8. Biomarkers in T cell therapy clinical trials

    Directory of Open Access Journals (Sweden)

    Kalos Michael

    2011-08-01

    Full Text Available Abstract T cell therapy represents an emerging and promising modality for the treatment of both infectious disease and cancer. Data from recent clinical trials have highlighted the potential for this therapeutic modality to effect potent anti-tumor activity. Biomarkers, operationally defined as biological parameters measured from patients that provide information about treatment impact, play a central role in the development of novel therapeutic agents. In the absence of information about primary clinical endpoints, biomarkers can provide critical insights that allow investigators to guide the clinical development of the candidate product. In the context of cell therapy trials, the definition of biomarkers can be extended to include a description of parameters of the cell product that are important for product bioactivity. This review will focus on biomarker studies as they relate to T cell therapy trials, and more specifically: i. An overview and description of categories and classes of biomarkers that are specifically relevant to T cell therapy trials, and ii. Insights into future directions and challenges for the appropriate development of biomarkers to evaluate both product bioactivity and treatment efficacy of T cell therapy trials.

  9. Repetitious nature of repaired DNA in mammalian cells. Progress report, June 1, 1975--May 31, 1976

    International Nuclear Information System (INIS)

    The specific activity of DNA isolated from cultured mammalian cells labeled with tritiated thymidine was determined for 20 minute intervals beginning at different times post-uv irradiation, during the period in which post-replication repair is presumed to occur. It was concluded that the radioactivity incorporated into the DNA synthesized at different times post-uv irradiation, during the period of presumed post-replication repair, is uniformly distributed throughout the genome

  10. Umbilical cord-derived mesenchymal stem cell transplantation combined with hyperbaric oxygen treatment for repair of traumatic brain injury

    Institute of Scientific and Technical Information of China (English)

    Hai-xiao Zhou; Zhi-gang Liu; Xiao-jiao Liu; Qian-xue Chen

    2016-01-01

    Transplantation of umbilical cord-derived mesenchymal stem cells (UC-MSCs) for repair of traumatic brain injury has been used in the clinic. Hyperbaric oxygen (HBO) treatment has long been widely used as an adjunctive therapy for treating traumatic brain injury. UC-MSC transplantation combined with HBO treatment is expected to yield better therapeutic effects on traumatic brain injury. In this study, we established rat models of severe traumatic brain injury by pressurized lfuid (2.5–3.0 atm impact force). The injured rats were then administered UC-MSC transplantationvia the tail vein in combination with HBO treatment. Compared with monotherapy, aquaporin 4 expression decreased in the injured rat brain, but growth-associated protein-43 expression, calaxon-like structures, and CM-Dil-positive cell number increased. Following combination therapy, however, rat cognitive and neurological function signiifcantly improved. UC-MSC transplantation combined with HBO therapyfor repair of traumatic brain injury shows better therapeutic effects than monotherapy and signiifcantly promotes recovery of neurological functions.

  11. Umbilical cord-derived mesenchymal stem cell transplantation combined with hyperbaric oxygen treatment for repair of traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Hai-xiao Zhou

    2016-01-01

    Full Text Available Transplantation of umbilical cord-derived mesenchymal stem cells (UC-MSCs for repair of traumatic brain injury has been used in the clinic. Hyperbaric oxygen (HBO treatment has long been widely used as an adjunctive therapy for treating traumatic brain injury. UC-MSC transplantation combined with HBO treatment is expected to yield better therapeutic effects on traumatic brain injury. In this study, we established rat models of severe traumatic brain injury by pressurized fluid (2.5-3.0 atm impact force. The injured rats were then administered UC-MSC transplantation via the tail vein in combination with HBO treatment. Compared with monotherapy, aquaporin 4 expression decreased in the injured rat brain, but growth-associated protein-43 expression, calaxon-like structures, and CM-Dil-positive cell number increased. Following combination therapy, however, rat cognitive and neurological function significantly improved. UC-MSC transplantation combined with HBO therapyfor repair of traumatic brain injury shows better therapeutic effects than monotherapy and significantly promotes recovery of neurological functions.

  12. Umbilical cord-derived mesenchymal stem cell transplantation combined with hyperbaric oxygen treatment for repair of traumatic brain injury.

    Science.gov (United States)

    Zhou, Hai-Xiao; Liu, Zhi-Gang; Liu, Xiao-Jiao; Chen, Qian-Xue

    2016-01-01

    Transplantation of umbilical cord-derived mesenchymal stem cells (UC-MSCs) for repair of traumatic brain injury has been used in the clinic. Hyperbaric oxygen (HBO) treatment has long been widely used as an adjunctive therapy for treating traumatic brain injury. UC-MSC transplantation combined with HBO treatment is expected to yield better therapeutic effects on traumatic brain injury. In this study, we established rat models of severe traumatic brain injury by pressurized fluid (2.5-3.0 atm impact force). The injured rats were then administered UC-MSC transplantation via the tail vein in combination with HBO treatment. Compared with monotherapy, aquaporin 4 expression decreased in the injured rat brain, but growth-associated protein-43 expression, calaxon-like structures, and CM-Dil-positive cell number increased. Following combination therapy, however, rat cognitive and neurological function significantly improved. UC-MSC transplantation combined with HBO therapyfor repair of traumatic brain injury shows better therapeutic effects than monotherapy and significantly promotes recovery of neurological functions. PMID:26981097

  13. The repair of cyclobutane dimers and PYR(6-4) PYO adducts in normal and repair-deficient mammalian cells

    International Nuclear Information System (INIS)

    Antiserum raised against DNA irradiated with a high dose of far UV light was found to have at least two antibody populations. A competitive assay in which the labelled antigen (/sup 32/P-labelled poly (dA):poly (dT)) was irradiated with far UV light (254nm) was shown to be specific for Pyr (6-4) Pyo adducts. Labelled antigen irradiated with near UV light (320nm) competed specifically for cyclobutane dimers. This assay had the same specificity as one consisting of labelled antigen irradiated with far UV light in competition for antiserum raised against DNA irradiated with near UV light in the presence of acetophenone. The authors conclude from these results that their previous data for removal of antibody-binding sites demonstrated repair of Pyr(6-4)Pyo adducts in normal, but not UV-hypersensitive, mammalian cell lines. Using the cyclobutane dimer-specific assay they have been able to correlate the removal of antibody-binding sites with repair kinetics previously published for T4 endonuclease V sensitive sites in mouse, hamster, normal human and Xeroderma pigmentosum cells

  14. Myocardial injection of apelin-overexpressing bone marrow cells improves cardiac repair via upregulation of Sirt3 after myocardial infarction.

    Directory of Open Access Journals (Sweden)

    Lanfang Li

    Full Text Available Our previous study shows that treatment with apelin increases bone marrow cells (BMCs recruitment and promotes cardiac repair after myocardial infarction (MI. The objective of this study was to investigate whether overexpression of apelin in BMCs improved cell therapy and accelerated cardiac repair and functional recovery in post-MI mice. Mouse myocardial infarction was achieved by coronary artery ligation and BMCs overexpressing apelin (apelin-BMCs or GFP (GFP-BMCs were injected into ischemic area immediately after surgery. In vitro, exposure of cultured BMCs to apelin led to a gradual increase in SDF-1á and CXCR4 expression. Intramyocardial delivery of apelin-BMCs in post-MI mice resulted in a significant increase number of APJ⁺/c-kit⁺/Sca1⁺ cells in the injected area compared to GFP-BMCs treated post-MI mice. Treatment with apelin-BMCs increased expression of VEGF, Ang-1 and Tie-2 in post-MI mice. Apelin-BMCs treatment also significantly increased angiogenesis and attenuated cardiac fibrosis formation in post-MI mice. Most importantly, treatment with apelin-BMCs significantly improved left ventricular (LV systolic function in post-MI mice. Mechanistically, Apelin-BMCs treatment led to a significant increase in Sirtuin3 (Sirt3 expression and reduction of reactive oxygen species (ROS formation. Treatment of cultured BMCs with apelin also increased Notch3 expression and Akt phosphorylation. Apelin treatment further attenuated stress-induced apoptosis whereas knockout of Sirt3 abolished anti-apoptotic effect of apelin in cultured BMCs. Moreover, knockout of Sirt3 significantly attenuated apelin-BMCs-induced VEGF expression and angiogenesis in post-MI mice. Knockout of Sirt3 further blunted apelin-BMCs-mediated improvement of cardiac repair and systolic functional recovery in post-MI mice. These data suggest that apelin improves BMCs therapy on cardiac repair and systolic function in post-MI mice. Upregulation of Sirt3 may contribute to the

  15. Myocardial injection of apelin-overexpressing bone marrow cells improves cardiac repair via upregulation of Sirt3 after myocardial infarction.

    Science.gov (United States)

    Li, Lanfang; Zeng, Heng; Hou, Xuwei; He, Xiaochen; Chen, Jian-Xiong

    2013-01-01

    Our previous study shows that treatment with apelin increases bone marrow cells (BMCs) recruitment and promotes cardiac repair after myocardial infarction (MI). The objective of this study was to investigate whether overexpression of apelin in BMCs improved cell therapy and accelerated cardiac repair and functional recovery in post-MI mice. Mouse myocardial infarction was achieved by coronary artery ligation and BMCs overexpressing apelin (apelin-BMCs) or GFP (GFP-BMCs) were injected into ischemic area immediately after surgery. In vitro, exposure of cultured BMCs to apelin led to a gradual increase in SDF-1á and CXCR4 expression. Intramyocardial delivery of apelin-BMCs in post-MI mice resulted in a significant increase number of APJ⁺/c-kit⁺/Sca1⁺ cells in the injected area compared to GFP-BMCs treated post-MI mice. Treatment with apelin-BMCs increased expression of VEGF, Ang-1 and Tie-2 in post-MI mice. Apelin-BMCs treatment also significantly increased angiogenesis and attenuated cardiac fibrosis formation in post-MI mice. Most importantly, treatment with apelin-BMCs significantly improved left ventricular (LV) systolic function in post-MI mice. Mechanistically, Apelin-BMCs treatment led to a significant increase in Sirtuin3 (Sirt3) expression and reduction of reactive oxygen species (ROS) formation. Treatment of cultured BMCs with apelin also increased Notch3 expression and Akt phosphorylation. Apelin treatment further attenuated stress-induced apoptosis whereas knockout of Sirt3 abolished anti-apoptotic effect of apelin in cultured BMCs. Moreover, knockout of Sirt3 significantly attenuated apelin-BMCs-induced VEGF expression and angiogenesis in post-MI mice. Knockout of Sirt3 further blunted apelin-BMCs-mediated improvement of cardiac repair and systolic functional recovery in post-MI mice. These data suggest that apelin improves BMCs therapy on cardiac repair and systolic function in post-MI mice. Upregulation of Sirt3 may contribute to the protective

  16. How we make cell therapy in Italy

    Directory of Open Access Journals (Sweden)

    Montemurro T

    2015-08-01

    Full Text Available Tiziana Montemurro, Mariele Viganò, Silvia Budelli, Elisa Montelatici, Cristiana Lavazza, Luigi Marino, Valentina Parazzi, Lorenza Lazzari, Rosaria GiordanoCell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, ItalyAbstract: In the 21st century scenario, new therapeutic tools are needed to take up the social and medical challenge posed by the more and more frequent degenerative disorders and by the aging of population. The recent category of advanced therapy medicinal products has been created to comprise cellular, gene therapy, and tissue engineered products, as a new class of drugs. Their manufacture requires the same pharmaceutical framework as for conventional drugs and this means that industrial, large-scale manufacturing process has to be adapted to the peculiar characteristics of cell-containing products. Our hospital took up the challenge of this new path in the early 2000s; and herein we describe the approach we followed to set up a pharmaceutical-grade facility in a public hospital context, with the aim to share the solutions we found to make cell therapy compliant with the requirements for the production and the quality control of a high-standard medicinal product.Keywords: advanced therapy medicinal product, good manufacturing practices, stem cells

  17. Gene and cell therapy for muscle regeneration

    OpenAIRE

    Stilhano, Roberta Sessa; Martins, Leonardo; Ingham, Sheila Jean McNeill; Pesquero, João Bosco; Huard, Johnny

    2015-01-01

    Skeletal muscle injury and healing are multifactorial processes, involving three steps of healing: (1) degeneration and inflammation, (2) regeneration, and (3) fibrosis. Fibrous tissue hinders the muscle’s complete recovery and current therapies fail in achieving total muscle recovery. Gene and cell therapy (or both) are potential future treatments for severe muscular injuries. Stem cells’ properties associated with growth factors or/and cytokines can improve muscle healing and permit long-te...

  18. Stem cell therapy independent of stemness

    OpenAIRE

    Lee, Techung

    2012-01-01

    Mesenchymal stem cell (MSC) therapy is entering a new era shifting the focus from initial feasibility study to optimization of therapeutic efficacy. However, how MSC therapy facilitates tissue regeneration remains incompletely characterized. Consistent with the emerging notion that secretion of multiple growth factors/cytokines (trophic factors) by MSC provides the underlying tissue regenerative mechanism, the recent study by Bai et al demonstrated a critical therapeutic role of MSC-derived h...

  19. Strategies for future histocompatible stem cell therapy

    DEFF Research Database (Denmark)

    Nehlin, Jan; Barington, Torben

    2009-01-01

    Stem cell therapy based on the safe and unlimited self-renewal of human pluripotent stem cells is envisioned for future use in tissue or organ replacement after injury or disease. A gradual decline of regenerative capacity has been documented among the adult stem cell population in some body organs...... during the aging process. Recent progress in human somatic cell nuclear transfer and inducible pluripotent stem cell technologies has shown that patient-derived nuclei or somatic cells can be reprogrammed in vitro to become pluripotent stem cells, from which the three germ layer lineages can be generated......, genetically identical to the recipient. Once differentiation protocols and culture conditions can be defined and optimized, patient-histocompatible pluripotent stem cells could be directed towards virtually every cell type in the human body. Harnessing this capability to enrich for given cells within...

  20. CELL THERAPY OF HEART PATHOLOGIES

    OpenAIRE

    Lukash, L.

    2008-01-01

    The review article is devoted to cellular cardiomyoplasty as a novel technology of treatment of cardiac insufficiency. The experiments on animals and the first clinical trials have shown the possibility to improve the contractile function of diseased heart after transplantation of different types of donor cells: cardiomyocytes, bone marrow enriched by hematopoietic stem cells and mesenchymal stem cells. The problems of cellular cardiomyoplasty are discussed.

  1. Suppression of DNA-dependent protein kinase sensitize cells to radiation without affecting DSB repair

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Ann-Sofie, E-mail: ann-sofie.gustafsson@bms.uu.se; Abramenkovs, Andris; Stenerlöw, Bo

    2014-11-15

    Highlights: • We reduced the level of DNA-PKcs with siRNA and examined cells after γ-irradiation. • Low DNA-PKcs levels lead to radiosensitivity but did not affect repair of DSB. • Low DNA-PKcs levels may block progression of mitosis. • DNA-PKcs role in mitotic progression is independent of its role in DSB repair. • We suggest different mechanisms by which loss of DNA-PKcs function sensitize cells. - Abstract: Efficient and correct repair of DNA double-strand break (DSB) is critical for cell survival. Defects in the DNA repair may lead to cell death, genomic instability and development of cancer. The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs) is an essential component of the non-homologous end joining (NHEJ) which is the major DSB repair pathway in mammalian cells. In the present study, by using siRNA against DNA-PKcs in four human cell lines, we examined how low levels of DNA-PKcs affected cellular response to ionizing radiation. Decrease of DNA-PKcs levels by 80–95%, induced by siRNA treatment, lead to extreme radiosensitivity, similar to that seen in cells completely lacking DNA-PKcs and low levels of DNA-PKcs promoted cell accumulation in G2/M phase after irradiation and blocked progression of mitosis. Surprisingly, low levels of DNA-PKcs did not affect the repair capacity and the removal of 53BP1 or γ-H2AX foci and rejoining of DSB appeared normal. This was in strong contrast to cells completely lacking DNA-PKcs and cells treated with the DNA-PKcs inhibitor NU7441, in which DSB repair were severely compromised. This suggests that there are different mechanisms by which loss of DNA-PKcs functions can sensitize cells to ionizing radiation. Further, foci of phosphorylated DNA-PKcs (T2609 and S2056) co-localized with DSB and this was independent of the amount of DNA-PKcs but foci of DNA-PKcs was only seen in siRNA-treated cells. Our study emphasizes on the critical role of DNA-PKcs for maintaining survival after radiation exposure

  2. Relevance of DNA repair pathways on ascorbic acid effects on Echerichia Coli K-12 cells

    International Nuclear Information System (INIS)

    Inactivation kinetics were performed with repair proficient and deficient Escherichia coli K-12 cells treated with oxidized solutions of ascorbic acid. The repair pathways controlled by the recA and uvrA gene products are essential for cell survival to the treatment. However, SOS chromotest result indicates that the SOS functions are only induced at high and toxic concentrations of the drug. Moreover, single strand breaks in DNA from treated cells are detected, demonstrating genome damage promoted by oxidized solutions of ascorbate. (M.A.C.)

  3. A novel method for monitoring functional lesion-specific recruitment of repair proteins in live cells

    International Nuclear Information System (INIS)

    Highlights: • A method of monitoring lesion-specific recruitment of proteins in vivo is described. • Recruitment of repair enzymes to abasic sites is monitored by co-localization. • Repair protein recruitment is consistent with known protein–protein relationships. • Cells demonstrated complete repair of abasic sites by 90 min. - Abstract: DNA–protein relationships have been studied by numerous methods, but a particular gap in methodology lies in the study of DNA adduct-specific interactions with proteins in vivo, which particularly affects the field of DNA repair. Using the repair of a well-characterized and ubiquitous adduct, the abasic (AP) site, as a model, we have developed a comprehensive method of monitoring DNA lesion-specific recruitment of proteins in vivo over time. We utilized a surrogate system in which a Cy3-labeled plasmid containing a single AP-site was transfected into cells, and the interaction of the labeled DNA with BER enzymes, including APE1, Polβ, LIG1, and FEN1, was monitored by immunofluorescent staining of the enzymes by Alexafluor-488-conjugated secondary antibody. The recruitment of enzymes was characterized by quantification of Cy3-Alexafluor-488 co-localization. To validate the microscopy-based method, repair of the transfected AP-site DNA was also quantified at various time points post-transfection using a real time PCR-based method. Notably, the recruitment time kinetics for each enzyme were consistent with AP-site repair time kinetics. This microscopy-based methodology is reliable in detecting the recruitment of proteins to specific DNA substrates and can be extended to study other in vivo DNA–protein relationships in any DNA sequence and in the context of any DNA structure in transfectable proliferating or quiescent cells. The method may be applied to a variety of disciplines of nucleic acid transaction pathways, including repair, replication, transcription, and recombination

  4. A novel method for monitoring functional lesion-specific recruitment of repair proteins in live cells

    Energy Technology Data Exchange (ETDEWEB)

    Woodrick, Jordan; Gupta, Suhani; Khatkar, Pooja; Dave, Kalpana; Levashova, Darya; Choudhury, Sujata; Elias, Hadi; Saha, Tapas; Mueller, Susette; Roy, Rabindra, E-mail: rr228@georgetown.edu

    2015-05-15

    Highlights: • A method of monitoring lesion-specific recruitment of proteins in vivo is described. • Recruitment of repair enzymes to abasic sites is monitored by co-localization. • Repair protein recruitment is consistent with known protein–protein relationships. • Cells demonstrated complete repair of abasic sites by 90 min. - Abstract: DNA–protein relationships have been studied by numerous methods, but a particular gap in methodology lies in the study of DNA adduct-specific interactions with proteins in vivo, which particularly affects the field of DNA repair. Using the repair of a well-characterized and ubiquitous adduct, the abasic (AP) site, as a model, we have developed a comprehensive method of monitoring DNA lesion-specific recruitment of proteins in vivo over time. We utilized a surrogate system in which a Cy3-labeled plasmid containing a single AP-site was transfected into cells, and the interaction of the labeled DNA with BER enzymes, including APE1, Polβ, LIG1, and FEN1, was monitored by immunofluorescent staining of the enzymes by Alexafluor-488-conjugated secondary antibody. The recruitment of enzymes was characterized by quantification of Cy3-Alexafluor-488 co-localization. To validate the microscopy-based method, repair of the transfected AP-site DNA was also quantified at various time points post-transfection using a real time PCR-based method. Notably, the recruitment time kinetics for each enzyme were consistent with AP-site repair time kinetics. This microscopy-based methodology is reliable in detecting the recruitment of proteins to specific DNA substrates and can be extended to study other in vivo DNA–protein relationships in any DNA sequence and in the context of any DNA structure in transfectable proliferating or quiescent cells. The method may be applied to a variety of disciplines of nucleic acid transaction pathways, including repair, replication, transcription, and recombination.

  5. Stem cell strategies for Alzheimer's disease therapy.

    Science.gov (United States)

    Sugaya, K; Alvarez, A; Marutle, A; Kwak, Y D; Choumkina, E

    2006-06-01

    We have found much evidence that the brain is capable of regenerating neurons after maturation. In our previous study, human neural stem cells (HNSCs) transplanted into aged rat brains differentiated into neural cells and significantly improved the cognitive functions of the animals, indicating that HNSCs may be a promising candidate for cell-replacement therapies for neurodegenerative diseases including Alzheimer's disease (AD). However, ethical and practical issues associated with HNSCs compel us to explore alternative strategies. Here, we report novel technologies to differentiate adult human mesenchymal stem cells, a subset of stromal cells in the bone marrow, into neural cells by modifying DNA methylation or over expression of nanog, a homeobox gene expressed in embryonic stem cells. We also report peripheral administrations of a pyrimidine derivative that increases endogenous stem cell proliferation improves cognitive function of the aged animal. Although these results may promise a bright future for clinical applications used towards stem cell strategies in AD therapy, we must acknowledge the complexity of AD. We found that glial differentiation takes place in stem cells transplanted into amyloid-( precursor protein (APP) transgenic mice. We also found that over expression of APP gene or recombinant APP treatment causes glial differentiation of stem cells. Although further detailed mechanistic studies may be required, RNA interference of APP or reduction of APP levels in the brain can significantly reduced glial differentiation of stem cells and may be useful in promoting neurogenesis after stem cell transplantation. PMID:16953146

  6. DNA repair: the culprit for tumor-initiating cell survival?

    OpenAIRE

    Mathews, Lesley A.; Cabarcas, Stephanie M.; Farrar, William L.

    2011-01-01

    The existence of “tumor-initiating cells” (TICs) has been a topic of heated debate for the last few years within the field of cancer biology. Their continuous characterization in a variety of solid tumors has led to an abundance of evidence supporting their existence. TICs are believed to be responsible for resistance against conventional treatment regimes of chemotherapy and radiation, ultimately leading to metastasis and patient demise. This review summarizes DNA repair mechanism(s) and the...

  7. Efficiency of Cell Therapy in Liver Cirrhosis.

    Science.gov (United States)

    Shevela, E Ya; Starostina, N M; Pal'tsev, A I; Shipunov, M V; Zheltova, O I; Meledina, I V; Khvan, L A; Leplina, O Yu; Ostanin, A A; Chernykh, E R; Kozlov, V A

    2016-02-01

    We studied safety and clinical efficacy of transplantation of autologous bone marrow cell in complex therapy of 158 patients with chronic hepatitis and cirrhosis of the liver. The efficiency of cell therapy was assessed in 12 months after single injection of the cells. The positive response (alleviation of liver cirrhosis or stabilization of the pathological process) was observed in 70% cases. The efficacy of therapy correlated with the severity and etiology of the disease and was maximum in patients with Child-Pugh class A (in 82.5% cases) and class B liver cirrhosis (in 79% cases); in patients with class C liver cirrhosis, the positive response was achieved in 42.5% cases. In 39 patients, ultrasonic examination performed in 3 years after transplantation revealed no focal lesions or ectopic ossification foci. PMID:26902361

  8. An Appropriate Response to the Black-Box Warning: Corrective, Barrier Repair Therapy in Atopic Dermatitis

    OpenAIRE

    Elias, Peter M

    2009-01-01

    Due to years of sophisticated research on T cell function, many dermatologists have viewed atopic dermatitis (AD) largely as an inflammatory disorder of TH1/TH2 imbalance. Hence, therapy has largely consisted of topical immunomodulators and/or steroids. The imposition of “black box” warnings about the potential toxicity associated with prolonged use of the immunosuppressive drugs, tacrolimus 0.1% or 0.3% ointment (Protopic®, Astellas Pharma U.S., Inc., Deerfield, IL) and pimecrolimus 1% cream...

  9. An Official American Thoracic Society Workshop Report 2015. Stem Cells and Cell Therapies in Lung Biology and Diseases.

    Science.gov (United States)

    Wagner, Darcy E; Cardoso, Wellington V; Gilpin, Sarah E; Majka, Susan; Ott, Harald; Randell, Scott H; Thébaud, Bernard; Waddell, Thomas; Weiss, Daniel J

    2016-08-01

    The University of Vermont College of Medicine, in collaboration with the NHLBI, Alpha-1 Foundation, American Thoracic Society, Cystic Fibrosis Foundation, European Respiratory Society, International Society for Cellular Therapy, and the Pulmonary Fibrosis Foundation, convened a workshop, "Stem Cells and Cell Therapies in Lung Biology and Lung Diseases," held July 27 to 30, 2015, at the University of Vermont. The conference objectives were to review the current understanding of the role of stem and progenitor cells in lung repair after injury and to review the current status of cell therapy and ex vivo bioengineering approaches for lung diseases. These are all rapidly expanding areas of study that both provide further insight into and challenge traditional views of mechanisms of lung repair after injury and pathogenesis of several lung diseases. The goals of the conference were to summarize the current state of the field, discuss and debate current controversies, and identify future research directions and opportunities for both basic and translational research in cell-based therapies for lung diseases. This 10th anniversary conference was a follow up to five previous biennial conferences held at the University of Vermont in 2005, 2007, 2009, 2011, and 2013. Each of those conferences, also sponsored by the National Institutes of Health, American Thoracic Society, and respiratory disease foundations, has been important in helping guide research and funding priorities. The major conference recommendations are summarized at the end of the report and highlight both the significant progress and major challenges in these rapidly progressing fields. PMID:27509163

  10. Measurement of DNA strand break repair and survival rate after X-irradiation of synchronized CHO cells

    International Nuclear Information System (INIS)

    The author investigated the induction and repair of DNA strand breaks and the survival rate of CHO cells after X-radiation at different stages of the cell cycle. His particular concern was the interdependence between cell inactivation and double strand break repair. (orig./AJ)

  11. Potential benefits and limitations of utilizing chondroprogenitors in cell-based cartilage therapy.

    Science.gov (United States)

    Jayasuriya, Chathuraka T; Chen, Qian

    2015-01-01

    Chondroprogenitor cells are a subpopulation of multipotent progenitors that are primed for chondrogenesis. They are believed to have the biological repertoire to be ideal for cell-based cartilage therapy. In addition to summarizing recent advances in chondroprogenitor cell characterization, this review discusses the projected pros and cons of utilizing chondroprogenitors in regenerative medicine and compares them with that of pre-existing methods, including autologous chondrocyte implantation (ACI) and the utilization of bone marrow derived mesenchymal stem cells (MSCs) for the purpose of cartilage tissue repair. PMID:26075411

  12. Cell therapy: A comparison of adult and embryonic stem cells

    Czech Academy of Sciences Publication Activity Database

    Syková, Eva; Jendelová, Pavla; Kozubenko, Nataliya

    Lille : organizátor symposia, 2010. S1-1-S1-1. [European Symposium on Stem Cell Research for Stroke . 04.05.2010-05.05.2010, Lille] Institutional research plan: CEZ:AV0Z50390703 Keywords : cell therapy * stem cells

  13. Efficiency of repair of pyrimidine dimers and psoralen monoadducts in normal and xeroderma pigmentosum human cells

    International Nuclear Information System (INIS)

    Repair of DNA damage produced by ultraviolet light or 5-methylisopsoralen in normal and xeroderma pigmentosum human cells involves many similar steps. Aphidicolin and cytosine arabinoside block repair of both kinds of damage with similar efficiency, indicating that DNA polymerase α has a major role in repair for these lesions. In xeroderma pigmentosum cells of various complementation groups, the relative efficiency of excision repair for both ultraviolet- and 5-methylisopsoralen-induced damage was group A< C< D, indicating a close resemblance between both kinds of lesions in relation to the repair deficiencies in these groups. At high doses, the maximum rate of repair of damage by ultraviolet light was about twice that for methylisopsoralen damage, possibly because ultraviolet-induced damage forms a substrate that is more readily recognized and excised than that of the psoralen adducts. Differences in the structural distortions to DNA caused by these kinds of damage could be detected using single strand specific nucleases which excised dimers but not 5-MIP adducts from double strand DNA. (author)

  14. Caffeine as a repair inhibitor and its action on the normal cell cycle in protozoa

    International Nuclear Information System (INIS)

    Caffeine has been demonstrated to inhibit repair of ionizing radiation damage, UV, and chemical DNA damage. The mechanism of caffeine action is not completely established at the present time but it has been clearly demonstrated that excision repair is inhibited in prokaryotes. The levels of caffeine which inhibit DNA repair are well tolerated by unirradiated organisms but radiation might impose an extra stress which would cause the irradiated organism to die from the normal caffeine sensitive function. The authors have tested synchronized protozoans at various times in the growth cycle for caffeine sensitivity. They infer sensitivity by the measured disruption of the normal growth cycle induced by a pulse treatment with lethal levels of caffeine. Some parts (G1) of the cell cycle show little sensitivity while late cycle (late S) may be quite sensitive. The relationship of cyclic caffeine sensitivity to repair inhibition is not obvious

  15. Bone Marrow Mesenchymal Stem Cell and Vein Conduit on Sciatic Nerve Repair in Rats

    Science.gov (United States)

    Seyed Foroutan, Kamal; Khodarahmi, Ali; Alavi, Hootan; Pedram, Sepehr; Baghaban Eslaminejad, Mohamad Reza; Bordbar, Sima

    2015-01-01

    Background: Peripheral nerve repair with sufficient functional recovery is an important issue in reconstructive surgery. Stem cells have attracted extensive research interest in recent years. Objectives: The purpose of this study was to compare the vein conduit technique, with and without the addition of mesenchymal stem cells in gap-less nerve injury repair in rats. Materials and Methods: In this study, 36 Wistar rats were randomly allocated to three groups: In the first group, nerve repair was performed with simple neurorrhaphy (control group), in the second group, nerve repair was done with vein conduit over site (vein conduit group) and in the third group, bone marrow stem cells were instilled into the vein conduit (stem cell group) after nerve repair with vein conduit over site. Six weeks after the intervention, the sciatic function index, electrophysiological study and histological examination were performed. Results: All animals tolerated the surgical procedures and survived well. The sciatic function index and latency were significantly improved in the vein conduit (P = 0.04 and 0.03, respectively) and stem cell group (P = 0.02 and 0.03, respectively) compared with the control group. No significant difference was observed in sciatic function and latency between the vein conduit and stem-cell groups. Moreover, histological analysis showed no significant difference in regenerative density between these two groups. Conclusions: The results of this study showed that the meticulous microsurgical nerve repair, which was performed using the vein tubulization induced significantly better sciatic nerve regeneration. However, the addition of bone marrow mesenchymal stem cell to vein conduit failed to promote any significant changes in regeneration outcome. PMID:25825699

  16. A novel cell death gene acts to repair patterning defects in Drosophila melanogaster.

    Science.gov (United States)

    Tanaka, Kentaro M; Takahashi, Aya; Fuse, Naoyuki; Takano-Shimizu-Kouno, Toshiyuki

    2014-06-01

    Cell death is a mechanism utilized by organisms to eliminate excess cells during development. Here, we describe a novel regulator of caspase-independent cell death, Mabiki (Mabi), that is involved in the repair of the head patterning defects caused by extra copies of bicoid in Drosophila melanogaster. Mabiki functions together with caspase-dependent cell death mechanisms to provide robustness during development. PMID:24671768

  17. Repair of ionizing radiation DNA base damage in ataxia-telangiectasia cells

    International Nuclear Information System (INIS)

    Micrococcus luteus endonuclease sensitive sites were measured by alkaline elution in normal human and ataxia-telangiectasia (AT) fibroblasts after ionizing radiation. Due to the sensitivity of this assay, repair of base damage after 3 to 6 kilorads has been measured after oxic or hypoxic radiation. With 5.5 kilorads of oxic radiation, more than 50% of the base damage was removed after 1.5 h of repair incubation in all cells, including exr+ and exr- AT cells, and approximately 75% was removed by 4 h. After 3 or 4.5 kilorads of hypoxic X-irradiation, repair was equivalent in normal and exr- AT cells. This study included three exr- AT strains which have been reported to be deficient in the removal of gamma-ray base damage at higher doses. Since these strains repaired ionizing radiation base damage normally at lower doses, which are more relevant to survival, it is concluded that the X-ray hypersensitivity of AT cells is probably not related to the repair of base damage

  18. Cell Therapy for Wound Healing

    OpenAIRE

    You, Hi-Jin; Han, Seung-Kyu

    2014-01-01

    In covering wounds, efforts should include utilization of the safest and least invasive methods with goals of achieving optimal functional and cosmetic outcome. The recent development of advanced wound healing technology has triggered the use of cells to improve wound healing conditions. The purpose of this review is to provide information on clinically available cell-based treatment options for healing of acute and chronic wounds. Compared with a variety of conventional methods, such as skin...

  19. Repair-deficient xeroderma pigmentosum cells made UV light resistant by fusion with X-ray-inactivated Chinese hamster cells

    International Nuclear Information System (INIS)

    Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The hybrid cells exhibited UV resistance and DNA repair characteristics comparable to those expressed by CHO cells, and their DNA had greater homology with CHO DNA than did the DNA from XP cells. Control experiments consisted of fusion of irradiated and unirradiated XP cells and repeated exposure of unfused XP cells to UV doses used for hybrid selection. These treatments did not result in an increase in UV resistance, repair capability, or homology with CHO DNA. The hybrid cell lines do not, therefore, appear to be XP revertants. The establishment of these stable hybrid cell lines is an initial step toward identifying and cloning CHO DNA repair genes that complement the XP defect in human cells. The method should also be applicable to cloning genes for other diseases, such as ataxia-telangiectasia and Fanconi's anemia

  20. Repair of spinal cord injury by neural stem cells transfected with brain-derived neurotrophic factor-green fluorescent protein in rats A double effect of stem cells and growth factors

    Institute of Scientific and Technical Information of China (English)

    Yansong Wang; Gang Lü

    2010-01-01

    Brain-derived neurotrophic factor(BDNF)can significantly promote nerve regeneration and repair.High expression of the BDNF-green fluorescent protein(GFP)gene persists for a long time after transfection into neural stem cells.Nevertheless,little is known about the biological characteristics of BDNF-GFP modified nerve stem cells in vivo and their ability to induce BDNF expression or repair spinal cord injury.In the present study,we transplanted BDNF-GFP transgenic neural stem cells into a hemisection model of rats.Rats with BDNF-GFP stem cells exhibited significantly increased BDNF expression and better locomotor function compared with stem cells alone.Cellular therapy with BDNF-GFP transgenic stem cells can improve outcomes better than stem cells alone and may have therapeutic potential for spinal cord injury.

  1. γ-ray dose rate effect in DNA double-strand break repair deficient murine cells

    International Nuclear Information System (INIS)

    Objective: To analyze the dose rate effect and potentially lethal damage repair in DNA double-strand break repair deficient murine cells (SCID) irradiated by γ-ray. Methods: The wild type (CB.17+/+) and SCID cells were exposed to γ-ray at high and low dose rates. The high dose rate exposure was fractionated into two equal doses at 24 h intervals. The survival rates of irradiated cells were calculated by clone-forming analysis. Results: When γ-ray was given to wild type (CB.17+/+) cells in two fractions at 24 h intervals, the survival rate was significantly higher than that when the same total dose was given singly. In contrast, there was no difference in the survival rates between the single and fractionated exposure in SCID cells. SCID cells were more sensitive than CB.17+/+ cells to both low and high dose rates γ-ray exposure for cell killing. The survival rate by low dose rate exposure was significantly higher than that by high dose rate exposure, not only in CB.17+/+ cells but also in SCID cells. Conclusions: SCID cells are deficient in repairing γ-ray induced double-strand breaks. There is dose rate effect in both SCID and CB.17+/+ cells

  2. The role of DNA repair on cell killing by charged particles

    Science.gov (United States)

    Eguchi-Kasai, K.; Murakami, M.; Itsukaichi, H.; Fukutsu, K.; Kanai, T.; Furusawa, Y.; Sato, K.; Ohara, H.; Yatagai, F.

    It can be noted that it is not simple double strand breaks (dsb) but the non-reparable breaks that are associated with high biological effectiveness in the cell killing effect for high LET radiation. Here, we have examined the effectiveness of fast neutrons and low (initial energy = 12 MeV/u) or high (135 MeV/u) energy charged particles on cell death in 19 mammalian cell lines including radiosensitive mutants. Some of the radiosensitive lines were deficient in DNA dsb repair such as LX830, M10, V3, and L5178Y-S cells and showed lower values of relative biological effectiveness (RBE) for fast neutrons if compared with their parent cell lines. The other lines of human ataxia-telangiectasia fibroblasts, irs 1, irs 2, irs 3 and irs1SF cells, which were also radiosensitive but known as proficient in dsb repair, showed moderate RBEs. Dsb repair deficient mutants showed low RBE values for heavy ions. These experimental findings suggest that the DNA repair system does not play a major role against the attack of high linear energy transfer (LET) radiations. Therefore, we hypothesize that a main cause of cell death induced by high LET radiations is due to non-reparable dsb, which are produced at a higher rate compared to low LET radiations.

  3. Prospect of Induced Pluripotent Stem Cell Genetic Repair to Cure Genetic Diseases

    Directory of Open Access Journals (Sweden)

    Jeanne Adiwinata Pawitan

    2012-01-01

    Full Text Available In genetic diseases, where the cells are already damaged, the damaged cells can be replaced by new normal cells, which can be differentiated from iPSC. To avoid immune rejection, iPSC from the patient’s own cell can be developed. However, iPSC from the patients’s cell harbors the same genetic aberration. Therefore, before differentiating the iPSCs into required cells, genetic repair should be done. This review discusses the various technologies to repair the genetic aberration in patient-derived iPSC, or to prevent the genetic aberration to cause further damage in the iPSC-derived cells, such as Zn finger and TALE nuclease genetic editing, RNA interference technology, exon skipping, and gene transfer method. In addition, the challenges in using the iPSC and the strategies to manage the hurdles are addressed.

  4. Application of Allogeneic Fibroblast Cells in Cellular Therapy of Recessive Dystrophic Epidermolysis Bullosa

    Directory of Open Access Journals (Sweden)

    Zare

    2015-09-01

    Full Text Available Context Connective tissue cells include fibroblasts, chondrocytes, adipocyte, and osteocytes. These cells are specialized for the secretion of collagenous extracellular matrix and are responsible for the architectural framework of the human body. Evidence Acquisition Connective tissue cells play a central role in supporting as well as repairing tissues and organs. Fibroblast cell therapy could be used for the treatment of burn wounds, scars, diabetic foot ulcers, acne scars and skin aging. This review focused on biology of fibroblasts and their role in cell therapy of recessive dystrophic epidermolysis bullosa (RDEB. Results Fibroblasts are known to play a pivotal role in skin structure and integrity, and dermal fibroblasts are believed to promote skin regeneration and rejuvenation via collagen production. Conclusions Fibroblasts can be used in transplantations to ameliorate an immune system response, in order to reduce antigen production. Human fibroblasts suppress ongoing mixed lymphocyte reactions (MLRs between lymphocyte cells from two individuals, and supernatant materials from fibroblast cultures suppress MLRs.

  5. uv photobiology: excision repair

    International Nuclear Information System (INIS)

    The following topics are discussed: steps in nucleotide excision; damage to DNA by uv-endonuclease; use of complementation to study DNA repair in Escherichia coli and mammalian cells; role of BUDR photolysis in excision repair, relation between DNA repair defect and human disease; base excision repair; and excision repair by removal of damaged region of a base in DNA without excision

  6. Repair responses to DNA damage: enzymatic pathways in E coli and human cells

    International Nuclear Information System (INIS)

    Bacteria and eukaryotic cells employ a variety of enzymatic pathways to remove damage from DNA or to lessen its impact upon cellular functions. Most of these processes were discovered in Escherichia coli and have been most extensively analyzed in this organism because suitable mutants have been isolated and characterized. Analogous pathways have been inferred to exist in mammalian cells from the presence of enzyme activities similar to those known to be involved in repair in bacteria, from the analysis of events in cells treated with DNA damaging agents, and from the analysis of the few naturally occurring mutant cell types. Mammalian cells possess an excision repair pathway similar to the constitutive pathway in E coli. Although not as well understood, the incision event is at least as complex, and repair resynthesis produces patches of about the same size as the constitutive short patches. In mammalian cells, no patches comparable in size to those produced by the inducible pathway of E coli are observed. Endonuclease V of bacteriophage T4 incises DNA at pyrimidine dimers by cleaving first the glycosylic bond between deoxyribose and the 5'pyrimidine of the dimer and then the phosphodiester bond between the two pyrimidines. We have cloned the gene (den V) that codes for this enzyme and have demonstrated its expression in uvrA recA and uvrB recA cells of E coli. Because T4 endonuclease V can alleviate the excission repair deficiency of xeroderma pigmentosum when added to permeabilized cells or to isolated nuclei after UV irradiation, the cloned denV gene may ultimately be of value for analyzing DNA repair pathways in cultured human cells

  7. Age and gender effects on DNA strand break repair in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Garm, Christian; Moreno-Villanueva, Maria; Bürkle, Alexander; Petersen, Inge; Bohr, Vilhelm A.; Christensen, Kaare; Stevnsner, Tinna V.

    2013-01-01

    single-strand breaks (SSBs) and double-strand breaks (DSBs) in human peripheral blood mononuclear cells (PBMCs). Of these lesions, DSBs are the least frequent but the most dangerous for cells. We have measured the level of endogenous SSBs, SSB repair capacity, γ-H2AX response, and DSB repair capacity in......Exogenous and endogenous damage to DNA is constantly challenging the stability of our genome. This DNA damage increase the frequency of errors in DNA replication, thus causing point mutations or chromosomal rearrangements and has been implicated in aging, cancer, and neurodegenerative diseases...

  8. How we make cell therapy in Italy.

    Science.gov (United States)

    Montemurro, Tiziana; Viganò, Mariele; Budelli, Silvia; Montelatici, Elisa; Lavazza, Cristiana; Marino, Luigi; Parazzi, Valentina; Lazzari, Lorenza; Giordano, Rosaria

    2015-01-01

    In the 21st century scenario, new therapeutic tools are needed to take up the social and medical challenge posed by the more and more frequent degenerative disorders and by the aging of population. The recent category of advanced therapy medicinal products has been created to comprise cellular, gene therapy, and tissue engineered products, as a new class of drugs. Their manufacture requires the same pharmaceutical framework as for conventional drugs and this means that industrial, large-scale manufacturing process has to be adapted to the peculiar characteristics of cell-containing products. Our hospital took up the challenge of this new path in the early 2000s; and herein we describe the approach we followed to set up a pharmaceutical-grade facility in a public hospital context, with the aim to share the solutions we found to make cell therapy compliant with the requirements for the production and the quality control of a high-standard medicinal product. PMID:26316716

  9. Mesenchymal stem cells: a new trend for cell therapy

    Institute of Scientific and Technical Information of China (English)

    Xin WEI; Xue YANG; Zhi-peng HAN; Fang-fang QU; Li SHAO; Yu-fang SHI

    2013-01-01

    Mesenchymal stem cells (MSCs),the major stem cells for cell therapy,have been used in the clinic for approximately 10 years.From animal models to clinical trials,MSCs have afforded promise in the treatment of numerous diseases,mainly tissue injury and immune disorders.In this review,we summarize the recent opinions on methods,timing and cell sources for MSC administration in clinical applications,and provide an overview of mechanisms that are significant in MSC-mediated therapies.Although MSCs for cell therapy have been shown to be safe and effective,there are still challenges that need to be tackled before their wide application in the clinic.

  10. Adult Stem Cell Therapy for Periodontal Disease

    OpenAIRE

    Kim, Su-Hwan; Seo, Byoung-Moo; Choung, Pill-Hoon; Lee, Yong-Moo

    2010-01-01

    Periodontal disease is a major cause of tooth loss and characterized by inflammation of tooth-supporting structures. Recently, the association between periodontal disease and other health problems has been reported, the importance of treating periodontal disease for general health is more emphasized. The ultimate goal of periodontal therapy is regeneration of damaged periodontal tissues. The development of adult stem cell research enables to improve the cell-based tissue engineering for perio...

  11. Large animal models for stem cell therapy

    OpenAIRE

    Harding, John; Roberts, R. Michael; Mirochnitchenko, Oleg

    2013-01-01

    The field of regenerative medicine is approaching translation to clinical practice, and significant safety concerns and knowledge gaps have become clear as clinical practitioners are considering the potential risks and benefits of cell-based therapy. It is necessary to understand the full spectrum of stem cell actions and preclinical evidence for safety and therapeutic efficacy. The role of animal models for gaining this information has increased substantially. There is an urgent need for nov...

  12. Development and application of compact and on-chip electron linear accelerators for dynamic tracking cancer therapy and DNA damage/repair analysis

    Science.gov (United States)

    Uesaka, M.; Demachi, K.; Fujiwara, T.; Dobashi, K.; Fujisawa, H.; Chhatkuli, R. B.; Tsuda, A.; Tanaka, S.; Matsumura, Y.; Otsuki, S.; Kusano, J.; Yamamoto, M.; Nakamura, N.; Tanabe, E.; Koyama, K.; Yoshida, M.; Fujimori, R.; Yasui, A.

    2015-06-01

    We are developing compact electron linear accelerators (hereafter linac) with high RF (Radio Frequency) frequency (9.3 GHz, wavelength 32.3 mm) of X-band and applying to medicine and non-destructive testing. Especially, potable 950 keV and 3.95 MeV linac X-ray sources have been developed for on-site transmission testing at several industrial plants and civil infrastructures including bridges. 6 MeV linac have been made for pinpoint X-ray dynamic tracking cancer therapy. The length of the accelerating tube is ∼600 mm. The electron beam size at the X-ray target is less than 1 mm and X-ray spot size at the cancer is less than 3 mm. Several hardware and software are under construction for dynamic tracking therapy for moving lung cancer. Moreover, as an ultimate compact linac, we are designing and manufacturing a laser dielectric linac of ∼1 MeV with Yr fiber laser (283 THz, wavelength 1.06 pm). Since the wavelength is 1.06 μm, the length of one accelerating strcture is tens pm and the electron beam size is in sub-micro meter. Since the sizes of cell and nuclear are about 10 and 1 μm, respectively, we plan to use this “On-chip” linac for radiation-induced DNA damage/repair analysis. We are thinking a system where DNA in a nucleus of cell is hit by ∼1 μm electron or X-ray beam and observe its repair by proteins and enzymes in live cells in-situ.

  13. Cancer Stem Cells, Cancer Cell Plasticity and Radiation Therapy

    OpenAIRE

    Vlashi, Erina; Pajonk, Frank

    2014-01-01

    Since the first prospective identification of cancer stem cells in solid cancers the cancer stem cell hypothesis has reemerged as a research topic of increasing interest. It postulates that solid cancers are organized hierarchically with a small number of cancer stem cells driving tumor growth, repopulation after injury and metastasis. They give rise to differentiated progeny, which lack these features. The model predicts that for any therapy to provide cure, all cancer stem cells have to be ...

  14. Telocytes as a Source of Progenitor Cells in Regeneration and Repair Through Granulation Tissue.

    Science.gov (United States)

    Díaz-Flores, Lucio; Gutiérrez, Ricardo; Pino García, Maria; González, Miriam; Díaz-Flores, Lucio; Francisco Madrid, Juan

    2016-01-01

    This review outlines the role of CD34+ stromal cells/telocytes (CD34+ SC/TCs) in repair and considers the following issues. Firstly, the conceptual aspects of repair, including regeneration and repair through granulation tissue (RTGT) as two types of repair, RTGT stages (inflammatory, proliferative, and remodeling), and tissue in repair as a substrate to assess the in vivo behavior of activated CD34+ SC/TCs. Subsequently, current knowledge of CD34+ SC/TCs, such as identification, characteristics, and functions, as well as possible stages (quiescent and activated) are taken into account. We then consider the role in regeneration of quiescent CD34+ SC/TCs (in unperturbed physiological conditions) as a nurse of stem cells (e.g., in the heart, skin, respiratory tree, gastrointestinal tract, liver, eye, and choroid plexus). Special attention is paid to the characteristics of activated CD34+ SC/TCs and the overlapping steps of activation with and without loss of CD34 expression and with and without gain of αSMA expression. With this contribution, we establish the role of CD34+ SC/TCs as progenitor cells and as a source of fibroblasts and myofibroblasts in repair through granulation tissue, fibrosis, and tumor stroma. Activated CD34+ SC/TCs in encapsulation and other processes (e.g., Reinke's edema, cutaneous myxoid cyst, mixomatous mitral valve degeneration, and fibrous papula of the face) are also outlined. Finally, similarities between modifications of CD34+ SC/TCs during in vivo activation and of multipotent mesenchymal stromal/stem cells in culture are examined in order to correlate the growing literature on CD34+ SC/TCs and the exponential research in cultured mesenchymal stromal/stem cells. PMID:26423297

  15. Human periodontal ligament stem cells repair mental nerve injury

    OpenAIRE

    Li, Bohan; Jung, Hun-Jong; Kim, Soung-Min; Kim, Myung-Jin; Jahng, Jeong Won; Lee, Jong-Ho

    2013-01-01

    Human periodontal ligament stem cells are easily accessible and can differentiate into Schwann cells. We hypothesized that human periodontal ligament stem cells can be used as an alternative source for the autologous Schwann cells in promoting the regeneration of injured peripheral nerve. To validate this hypothesis, human periodontal ligament stem cells (1 × 106) were injected into the crush-injured left mental nerve in rats. Simultaneously, autologous Schwann cells (1 × 106) and PBS were al...

  16. Neocarzinostatin-mediated DNA damage and repair in wild-type and repair-deficient Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    The formation and repair of neocarzinostatin (NCS)-mediated DNA damage were examined in two strains of Chinese hamster ovary cells. The response in strain EM9, a mutant line selected for its sensitivity to ethyl methanesulfonate and shown to have a defect in the repair of X-ray-induced DNA breaks, was compared with that observed in the parental strain (AA8). The DNA strand breaks and their subsequent rejoining were measured using the method of elution of DNA from filters under either alkaline (for single-strand breaks), or nondenaturing conditions (for double-strand breaks). Colony survival assays showed that the mutant was more sensitive to the action of NCS than was the parental strain by a factor of approximately 1.5. Elution analyses showed that the DNA from both strains was damaged by NCS; the mutant displayed more damage than the parent under the same treatment conditions. Single-strand breaks were produced with a frequency of about 10 to 15 times the frequency of double-strand breaks. Both strains were able to rejoin both single-strand breaks and double-strand breaks induced by NCS treatment. The strand break data suggest that the difference in NCS-mediated cytotoxicity between EM9 and AA8 cells may be directly related to the enhanced production of DNA strand breaks in EM9. However, the fact that much higher doses of NCS were required in the DNA studies compared to the colony survival assays implies that either a small number of DNA breaks occur in a critical region of the genome, or that lesions other than DNA strand breaks are partly responsible for the observed cytotoxicity

  17. Progress and prospects in stem cell therapy

    Institute of Scientific and Technical Information of China (English)

    Xiu-ling XU; Fei YI; Hui-ze PAN; Shun-lei DUAN; Zhi-chao DING; Guo-hong YUAN; Jing QU

    2013-01-01

    In the past few years,progress being made in stem cell studies has incontestably led to the hope of developing cell replacement based therapy for diseases deficient in effective treatment by conventional ways.The induced pluripotent stem cells (iPSCs) are of great interest of cell therapy research because of their unrestricted self-renewal and differentiation potentials.Proof of principle studies have successfully demonstrated that iPSCs technology would substantially benefit clinical studies in various areas,including neurological disorders,hematologic diseases,cardiac diseases,liver diseases and etc.On top of this,latest advances of gene editing technologies have vigorously endorsed the possibility of obtaining disease-free autologous cells from patient specific iPSCs.Here in this review,we summarize current progress of stem cell therapy research with special enthusiasm in iPSCs studies.In addition,we compare current gene editing technologies and discuss their potential implications in clinic application in the future.

  18. Polymorphisms in human DNA repair genes and head and neck squamous cell carcinoma

    Indian Academy of Sciences (India)

    Rim Khlifi; Ahmed Rebai; Amel Hamza-Chaffai

    2012-12-01

    Genetic polymorphisms in some DNA repair proteins are associated with a number of malignant transformations like head and neck squamous cell carcinoma (HNSCC). Xeroderma pigmentosum group D (XPD) and X-ray repair cross-complementing proteins 1 (XRCC1) and 3 (XRCC3) genes are involved in DNA repair and were found to be associated with HNSCC in numerous studies. To establish our overall understanding of possible relationships between DNA repair gene polymorphisms and development of HNSCC, we surveyed the literature on epidemiological studies that assessed potential associations with HNSCC risk in terms of gene–environment interactions, genotype-induced functional defects in enzyme activity and/or protein expression, and the influence of ethnic origin on these associations.We conclude that large, well-designed studies of common polymorphisms in DNA repair genes are needed. Such studies may benefit from analysis of multiple genes or polymorphisms and from the consideration of relevant exposures that may influence the likelihood of HNSCC when DNA repair capacity is reduced.

  19. TOPICAL REVIEW: Stem cells engineering for cell-based therapy

    Science.gov (United States)

    Taupin, Philippe

    2007-09-01

    Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

  20. Mesenchymal stem cells: cell biology and potential use in therapy

    DEFF Research Database (Denmark)

    Kassem, Moustapha; Kristiansen, Malthe; Abdallah, Basem M

    2004-01-01

    Mesenchymal stem cells are clonogenic, non-haematopoietic stem cells present in the bone marrow and are able to differentiate into multiple mesoderm-type cell lineages e.g. osteoblasts, chondrocytes, endothelial-cells and also non-mesoderm-type lineages e.g. neuronal-like cells. Several methods...... are currently available for isolation of the mesenchymal stem cells based on their physical and immunological characteristics. Because of the ease of their isolation and their extensive differentiation potential, mesenchymal stem cells are among the first stem cell types to be introduced in the clinic. Recent...... studies have demonstrated that the life span of mesenchymal stem cells in vitro can be extended by increasing the levels of telomerase expression in the cells and thus allowing culture of large number of cells needed for therapy. In addition, it has been shown that it is possible to culture the cells...

  1. Repair of ultraviolet radiation damage in xeroderma pigmentosum cells belonging to complementation group F

    International Nuclear Information System (INIS)

    DNA-repair characteristics of xeroderma pigmentosum belonging to complementation group F were investigated. The cells exhibited an intermediate level of repair as measured in terms of (1) disappearance of T4 endonuclease-V-susceptible sites from DNA, (2) formation of ultraviolet-induced strand breaks in DNA, and (3) ultraviolet-induced unscheduled DNA synthesis during post-irradiation incubation. The impaired ability of XP3YO to perform unscheduled DNA synthesis was restored, to half the normal level, by the concomitant treatment with T4 endonuclease V and ultraviolet-inactivated Sendai virus. It is suggested that xeroderma pigmentosum cells of group F may be defective, at least in part, in the incision step of excision repair. (orig.)

  2. Repair of X-ray-induced single-strand breaks by a cell-free system

    International Nuclear Information System (INIS)

    Repair of X-ray-induced single-strand breaks of DNA was studied in vitro using an exonuclease purified from mouse ascites sarcoma (SR-C3H/He) cells. X-ray-dose-dependent unscheduled DNA synthesis was primed by the exonuclease. Repair of X-ray-induced single-strand breaks in pUC19 plasmid DNA was demonstrated by agarose gel electrophoresis after incubating the damaged DNA with the exonuclease, DNA polymerase (Klenow fragment of DNA polymerase I or DNA polymerase β purified from SR-C3H/He cells), four deoxynucleoside triphosphates, ATP and DNA ligase (T4 DNA ligase or DNA ligase I purified from calf thymus). The present results suggested that the exonuclease is involved in the initiation of repair of X-ray-induced single-strand breaks in removing 3' ends of X-ray-damaged DNA. (author)

  3. Distinctions in sensitivity and repair of cells of children with some hereditary diseases

    Energy Technology Data Exchange (ETDEWEB)

    Zasukhina, G.D.; Barashnev, Yu.I.; Vasil' eva, I.M.; Sdirkova, N.I.; Semyachkina, A.N. (AN SSSR, Moscow. Inst. Obshchej Genetiki)

    A study was made of blood cell sensitivity of children with some hereditary diseases, to ..gamma..-radiation and 4-nitro-quinoline-1-oxide. Using the host cell reactivation and chromatographic methods we revealed the increase in the sensitivity to the above mentioned agents and inhibition of the repair function in cells of patients with the following diseases: Marfan's disease, histidinemia, osteogenesis imperfecta, Sylvere-Russelle, Laurence, Franchescetti, and Losch-Nychane syndromes.

  4. Distinctions in sensitivity and repair of cells of children with some hereditary diseases

    International Nuclear Information System (INIS)

    A study was made of blood cell sensitivity of children, with some hereditary diseases, to ν-radiation and 4-nitro-quinoline-1-oxide. Using the host cell reactivation and chromatographic methods we revealed the increase in the sensitivity to the above mentioned agents and inhibition of the repair function in cells of patients with the following diseases: Marfan's disease, histidinemia, osteogenesis imperfecta, Sylvere-Russelle, Laurence, Franchescetti, and Losch-Nychane syndromes

  5. Large scale isolation of DNA repair mutants of Chinese hamster ovary cells

    International Nuclear Information System (INIS)

    A semiautomated procedure has been designed and used successfully to permit the isolation of a large number of uv (ultraviolet light) sensitive mutant colonies of Chinese hamster ovary (CHO) cells. 149 uv sensitive mutants of CHO cells have been isolated to date by this procedure. This represents the largest in vitro isolation to date of uv sensitive mutants of mammalian cells The isolation of uv sensitive clones of EM9-1 represents the first stepwise isolation of double mutants of mammalian cells with sensitivity to an increased range of carcinogenic agents. Using a rapid screening test for complementation group assignment, 70 of these mutants have been assigned to a total of 5 complementation classes. Representatives of 4 of these classes have been studied for competence in repair replication following uv irradiation and have demonstrated a defective phenotype in uv repair. Representatives of 2 of these repair-deficient classes have been studies for uv mutagenic response for three selective markers, and have demonstrated an approximately ninefold enhancement in mutant yield per unit uv exposure relative to the parental cels. The sensitivity, repair phenotype, and mutational response ofthe isolates studied resemble that of human mutant xeroderma pigmentosum cells

  6. Transplantation of bone marrow derived cells promotes pancreatic islet repair in diabetic mice

    International Nuclear Information System (INIS)

    The transplantation of bone marrow (BM) derived cells to initiate pancreatic regeneration is an attractive but as-yet unrealized strategy. Presently, BM derived cells from green fluorescent protein transgenic mice were transplanted into diabetic mice. Repair of diabetic islets was evidenced by reduction of hyperglycemia, increase in number of islets, and altered pancreatic histology. Cells in the pancreata of recipient mice co-expressed BrdU and insulin. Double staining revealed β cells were in the process of proliferation. BrdU+ insulin- PDX-1+ cells, Ngn3+ cells and insulin+ glucagon+ cells, which showed stem cells, were also found during β-cell regeneration. The majority of transplanted cells were mobilized to the islet and ductal regions. In recipient pancreas, transplanted cells simultaneously expressed CD34 but did not express insulin, PDX-1, Ngn3, Nkx2.2, Nkx6.1, Pax4, Pax6, and CD45. It is concluded that BM derived cells especially CD34+ cells can promote repair of pancreatic islets. Moreover, both proliferation of β cells and differentiation of pancreatic stem cells contribute to the regeneration of β cells

  7. Carcinogen-induced DNA repair in nucleotide-permeable Escherichia coli cells

    International Nuclear Information System (INIS)

    Upon exposure to the carcinogens N-acetoxy-N-2-acetylaminofluorene and 7-bromomethyl-benz[a]anthracene, which bind covalently to DNA, ether-permeabilized (nucleotide-permeable) Escherichia coli wild-type cells responded with DNA excision repair. This repair was missing in mutants carrying defects in genes uvrA, uvrB and uvrC, whereas it was present in uvrD and several rec mutants. Enzymic activities involved were identified by measuring repair polymerization and size reduction of denatured DNA. An easily measurable effect in E. coli wild-type cells was carcinogen-induced repair polymerization. When initiated by N-acetoxy-N-2-acetylaminofluorene or 7-bromomethyl-benz[a]anthracene, it depended upton an ATP-requiring step; CTP, GTP or UTP did not substitute for ATP. DNA repair synthesis was inhibited by p-chloromercuribenzoate and quinacrine. In uvrA, uvrB and uvrC mutants no carcinogen-stimulated DNA synthesis could be detected, indicating that steps involved in pyrimidine dimer excision are also involved in chemorepair. In recA, recB and recC mutant cells, repair synthesis was stimulated by the carcinogens to a normal extent. This evidence excludes the ATP-dependent recB,C deoxyribonuclease and recA gene products as playing an important role in carcinogen-induced excision repair. polA1 cells showed drastically reduced levels of repair polymerization, indicating that DNA polymerase I is the main polymerizing enzyme. As determined by DNA size reduction in alkaline sucrose gradients, the arylalkylating carcinogens caused endonucleolytic cleavage of endogenous DNA in wild-type cells. This incision step was most effectively performed in the presence of ATP; UTP, CTP and GTP were only slightly effective. Incision was inhibited by p-chloromercuribenzoate and quinacrine. When exposed to the arylalkylating carcinogens, uvrA, uvrB and uvrC mutant cells did not perform the incision step in the presence of ATP, suggesting the involvement of the respective gene products in the

  8. Heterogeneous Stem Cells in Skin Homeostatis and Wound Repair

    OpenAIRE

    Anna Meilana; Nurrani Mustika Dewi; Andi Wijaya

    2015-01-01

    BACKGROUND: The skin protects mammals from insults, infection and dehydration and enables thermoregulation and sensory perception. Various skin-resident cells carry out these diverse functions. Constant turnover of cells and healing upon injury necessitate multiple reservoirs of stem cells. The skin is a complex organ harboring several distinct populations of stem cells and a rich array of cell types. Advances in genetic and imaging tools have brought new findings about the lineage relationsh...

  9. Hydrogen peroxide induced genomic instability in nucleotide excision repair-deficient lymphoblastoid cells

    Directory of Open Access Journals (Sweden)

    Gopalakrishnan Kalpana

    2010-12-01

    Full Text Available Abstract Background The Nucleotide Excision Repair (NER pathway specialises in UV-induced DNA damage repair. Inherited defects in the NER can predispose individuals to Xeroderma Pigmentosum (XP. UV-induced DNA damage cannot account for the manifestation of XP in organ systems not directly exposed to sunlight. While the NER has recently been implicated in the repair of oxidative DNA lesions, it is not well characterised. Therefore we sought to investigate the role of NER factors Xeroderma Pigmentosum A (XPA, XPB and XPD in oxidative DNA damage-repair by subjecting lymphoblastoid cells from patients suffering from XP-A, XP-D and XP-B with Cockayne Syndrome to hydrogen peroxide (H2O2. Results Loss of functional XPB or XPD but not XPA led to enhanced sensitivity towards H2O2-induced cell death. XP-deficient lymphoblastoid cells exhibited increased susceptibility to H2O2-induced DNA damage with XPD showing the highest susceptibility and lowest repair capacity. Furthermore, XPB- and XPD-deficient lymphoblastoid cells displayed enhanced DNA damage at the telomeres. XPA- and XPB-deficient lymphoblastoid cells also showed differential regulation of XPD following H2O2 treatment. Conclusions Taken together, our data implicate a role for the NER in H2O2-induced oxidative stress management and further corroborates that oxidative stress is a significant contributing factor in XP symptoms. Resistance of XPA-deficient lymphoblastoid cells to H2O2-induced cell death while harbouring DNA damage poses a potential cancer risk factor for XPA patients. Our data implicate XPB and XPD in the protection against oxidative stress-induced DNA damage and telomere shortening, and thus premature senescence.

  10. Stem cell therapy for retinal diseases

    Institute of Scientific and Technical Information of China (English)

    Jose Mauricio Garcia,; Luisa Mendon?a; Rodrigo Brant; Murilo Abud; Caio Regatieri; Bruno Diniz

    2015-01-01

    In this review, we discuss about current knowledgeabout stem cell (SC) therapy in the treatment of retinaldegeneration. Both human embryonic stem cell andinduced pluripotent stem cell has been growth inculture for a long time, and started to be explored inthe treatment of blinding conditions. The Food andDrug Administration, recently, has granted clinical trialsusing SC retinal therapy to treat complex disorders, asStargardt's dystrophy, and patients with geographicatrophy, providing good outcomes. This study'sintent is to overview the critical regeneration of thesubretinal anatomy through retinal pigment epitheliumtransplantation, with the goal of reestablish importantpathways from the retina to the occipital cortex of thebrain, as well as the differentiation from pluripotentquiescent SC to adult retina, and its relationshipwith a primary retinal injury, different techniques oftransplantation, management of immune rejection andtumorigenicity, its potential application in improvingpatients' vision, and, finally, approaching future directionsand challenges for the treatment of several conditions.

  11. Denaturation of DNA repair proteins as a possible rate limiting step in the thermal death of single cells

    International Nuclear Information System (INIS)

    The experiments to be described support the hypothesis that the denaturation of DNA repair proteins is a rate limiting step in the thermal death of cells grown in tissue culture. Mammalian fibroblasts were subjected to small changes in temperature before ultraviolet (uv) irradiation in order to detect changes in repair of uv induced damage. Repair of DNA was measured by several methods after uv treatment. In some experiments repair was measured by incorporating 3H-Thymidine at 370C for different lengths of time after uv irradiation. Autoradiography suggested that prior heat treatment impairs the repair in all of the cells rather than causes the thermal death of a large portion of the cells. Finally, an endonuclease specific assay was conducted to determine whether the effects were due to the thermal denaturation of the endonuclease repair enzyme or rather to some heat sensitive process. By using a dimer specific endonuclease from M. luteus, the number of dimers produced and repaired was measured directly. For both hamster ahd human fibroblasts, significantly less repair was observed in cells incubated at 410C prior to uv treatment than in cells incubated at 370C before uv treatment. This suggests that the endonuclease repair enzymes are denatured at the higher temperature

  12. CAR-T Cell Therapy for Lymphoma.

    Science.gov (United States)

    Ramos, Carlos A; Heslop, Helen E; Brenner, Malcolm K

    2016-01-01

    Lymphomas arise from clonal expansions of B, T, or NK cells at different stages of differentiation. Because they occur in the immunocyte-rich lymphoid tissues, they are easily accessible to antibodies and cell-based immunotherapy. Expressing chimeric antigen receptors (CARs) on T cells is a means of combining the antigen-binding site of a monoclonal antibody with the activating machinery of a T cell, enabling antigen recognition independent of major histocompatibility complex restriction, while retaining the desirable antitumor properties of a T cell. Here, we discuss the basic design of CARs and their potential advantages and disadvantages over other immune therapies for lymphomas. We review current clinical trials in the field and consider strategies to improve the in vivo function and safety of immune cells expressing CARs. The ultimate driver of CAR development and implementation for lymphoma will be the demonstration of their ability to safely and cost-effectively cure these malignancies. PMID:26332003

  13. The clinical relevance of cell-based therapy for the treatment of stress urinary incontinence

    DEFF Research Database (Denmark)

    Gräs, Søren; Lose, Gunnar

    2011-01-01

    Stress urinary incontinence is a common disorder affecting the quality of life for millions of women worldwide. Effective surgical procedures involving synthetic permanent meshes exist, but significant short- and long-term complications occur. Cell-based therapy using autologous stem cells or...... provided proof of concept for the idea. An initial enthusiasm caused by positive results from early clinical trials has been dampened by the recognition of scientific irregularities. At the same time, the safety issue for cell-based therapy has been highlighted by the appearance of new and comprehensive...... progenitor cells presents an alternative approach, which aims at repairing the anatomical components of the urethral continence mechanism. In vitro expanded progenitor cells isolated from muscle biopsies have been most intensely investigated, and both preclinical trials and a few clinical trials have...

  14. Propofol promotes spinal cord injury repair by bone marrow mesenchymal stem cell transplantation

    Institute of Scientific and Technical Information of China (English)

    Ya-jing Zhou; Jian-min Liu; Shu-ming Wei; Yun-hao Zhang; Zhen-hua Qu; Shu-bo Chen

    2015-01-01

    Propofol is a neuroprotective anesthetic. Whether propofol can promote spinal cord injury repair by bone marrow mesenchymal stem cells remains poorly understood. We used rats to investigate spinal cord injury repair using bone marrow mesenchymal stem cell transplantation combined with propofol administrationvia the tail vein. Rat spinal cord injury was clearly alleviated; a large number of newborn non-myelinated and myelinated nerve ifbers appeared in the spinal cord, the numbers of CM-Dil-labeled bone marrow mesenchymal stem cells and lfuorogold-labeled nerve ifbers were increased and hindlimb motor function of spinal cord-injured rats was mark-edly improved. These improvements were more prominent in rats subjected to bone marrow mesenchymal cell transplantation combined with propofol administration than in rats receiving monotherapy. These results indicate that propofol can enhance the therapeutic effects of bone marrow mesenchymal stem cell transplantation on spinal cord injury in rats.

  15. In-cell crane and repair hoist for power reactor and nuclear fuel development corporation

    International Nuclear Information System (INIS)

    Transformation of the high-level radioactive liquid waste into stable vitrification has been proceeding as a national project by PNC (Power Reactor and Nuclear Fuel Development Corporation). IHI has participated in this project as a main member and has undertaken development and designing of the key technology and facilities of the demonstrational plant. The in-cell crane and repair hoise are the mock up that had been developed for simulating remote technology and remote handling other facilities in the mock vitrification cell that were constructed at the PNC Tokai Works. The in-cell crane installed in the radioactive atmospheric cell has the ability of remote maintenance itself in addition to remote handling other facilities and repair hoist installed on the ceiling of the cell is used for remote maintenance of other machines. (author)

  16. Stem cells for cell replacement therapy: a therapeutic strategy for HD?

    Science.gov (United States)

    Rosser, Anne; Svendsen, Clive N

    2014-09-15

    Much interest has been expressed over the last couple of decades in the potential application of stem cells to medicine, both for research and diagnostic tools and as a source of donor cells for therapeutic purposes. Potential therapeutic applications include replacement of cells in many body organs where the capacity for intrinsic repair is limited, including the pancreas, heart, and brain. A key challenge is to generate the relevant donor cell types, and this is particularly challenging in the brain where the number of different neuronal subtypes is so great. Although dopamine neuron replacement in Parkinson's disease has been the focus of most clinical studies, great interest has been shown in this approach for other disorders, including Huntington's disease. Replacing complete neural circuits in the adult brain is clearly challenging, and there are many other complexities with regard to both donor cells and host. This article presents the pros and cons of taking a cell therapy approach in Huntington's disease. It considers the implantation both of cells that are already of the same neural subtype as those lost in the disease process (ie, primary fetal cells derived from the developing striatum) and those derived from stem cells, which require "directing" toward that phenotype. PMID:25216372

  17. Differences in repair of radiation induced damage in two human tumor cell lines as measured by cell survival and alkaline DNA unwinding

    International Nuclear Information System (INIS)

    We studied the relationship between the repair of radiation induced DNA strand breaks and cellular repair kinetics in two human tumor cell lines, NB-100 (neuroblastoma) and HN-1 (squamous cell carcinoma). Damage was quantified using the fluorometric analysis of DNA unwiding (FADU) for DNA damage, and cell survival was assessed using a clonogenic assay. In plateau phase cells repair of sublethal damage was virtually absent in NB-100 after 4 Gy (recovery ratio 1.0), whereas HN-1 cells did show sublethal damage repair (recovery ratio 1.4). Repair of potentially lethal damage was more pronounced in NB-100 cells (recovery ratio 2.3) than in HN-1 cells (recovery ratio 1.7) after 4 Gy. Graded doses of X-rays induced comparable levels of DNA damage in both tumor cell lines. However, in HN-1 cells more DNA strand breaks were repaired after 4 Gy, leaving about 25% of the initial damage unrepaired, whereas in NB-100 about 50% was unrepaired. This higher fraction of unrepaired DNA damage correlated well with the degree of sublethal damage repair which was lower in NB-100 than in HN-1 cell, but it did not correlate with the repair of potentially lethal damage, which was higher in NB-100 than in HN-1. Since the level of damage remaining post-irradiation may be the critical variable for survival, the FADU technique can contribute in elucidating the relationship between radiosensitivity and DNA damage repair capacity. (orig.)

  18. Stem Cell Therapy Shows Promise Against Heart Failure

    Science.gov (United States)

    ... nlm.nih.gov/medlineplus/news/fullstory_158122.html Stem Cell Therapy Shows Promise Against Heart Failure A second ... 4, 2016 MONDAY, April 4, 2016 (HealthDay News) -- Stem cell therapy shows promise for people battling heart failure, ...

  19. Intraspinal transplantation of motoneuron-like cell combined with delivery of polymer-based glial cell line-derived neurotrophic factor for repair of spinal cord contusion injury

    Institute of Scientific and Technical Information of China (English)

    Alireza Abdanipour; Taki Tiraihi; Taher Taheri

    2014-01-01

    To evaluate the effects of glial cell line-derived neurotrophic factor transplantation combined with adipose-derived stem cells-transdifferentiated motoneuron delivery on spinal cord con-tusion injury, we developed rat models of spinal cord contusion injury, 7 days later, injected adipose-derived stem cells-transdifferentiated motoneurons into the epicenter, rostral and caudal regions of the impact site and simultaneously transplanted glial cell line-derived neuro-trophic factor-gelfoam complex into the myelin sheath. Motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery reduced cavity formations and increased cell density in the transplantation site. The combined therapy exhibited superior promoting effects on recovery of motor function to transplantation of glial cell line-derived neurotrophic factor, adipose-derived stem cells or motoneurons alone. These ifndings suggest that motoneuron-like cell transplantation combined with glial cell line-derived neurotrophic factor delivery holds a great promise for repair of spinal cord injury.

  20. Role of endogenous Schwann cells in tissue repair after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Shu-xin Zhang; Fengfa Huang; Mary Gates; Eric G. Holmberg

    2013-01-01

    Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types that are widely studied and most commonly used for cell transplantation to treat spinal cord injury, due to their intrinsic characteristics including the ability to secrete a variety of neurotrophic factors. This mini review summarizes the recent findings of endogenous Schwann cells after spinal cord injury and discusses their role in tissue repair and axonal regeneration. After spinal cord injury, numerous endogenous Schwann cells migrate into the lesion site from the nerve roots, involving in the construction of newly formed repaired tissue and axonal myelination. These invading Schwann cells also can move a long distance away from the injury site both rostrally and caudally. In addition, Schwann cells can be induced to migrate by minimal insults (such as scar ablation) within the spinal cord and integrate with astrocytes under certain circumstances. More importantly, the host Schwann cells can be induced to migrate into spinal cord by transplantation of different cell types, such as exogenous Schwann cells, olfactory ensheathing cells, and bone marrow-derived stromal stem cells. Migration of endogenous Schwann cells following spinal cord injury is a common natural phenomenon found both in animal and human, and the myelination by Schwann cells has been examined effective in signal conduction electrophysiologically. Therefore, if the inherent properties of endogenous Schwann cells could be developed and utilized, it would offer a new avenue for the restoration of injured spinal cord.

  1. Radiobiological study on DNA strand breaks and repair using single cell gel electrophoresis

    International Nuclear Information System (INIS)

    Single cell gel electrophoresis (SCGE) provides a novel method to measure DNA damage in individual cells and more importantly, to assess heterogeneity in response within a mixed population of cells. Cells embedded in agarose are lysed, subjected to electrophoresis, stained with a fluorescent DNA-specific dye, and viewed under a fluorescence microscope. Damaged cells display 'comets', broken DNA migrating farther to the anode in the electric field. We have previously used this technique to quantify DNA damage induced by moderate doses of low and high LET radiations in cultured Chinese hamster cells. The assay has been optimized in terms of lysing and electrophoresis conditions, and applied to analyse the DNA strand breaks, their repair kinetics and heterogeneity in response in individual Chinese hamster cells exposed to gamma-rays, and to KUR thermal neutrons with and without 10B or to KEK PF monochromatic soft X-rays as well as to a radio-mimetic agent, neocarzinostatin. The DNA double-strand breaks induced by boron-neutron captured reactions were repaired at a slower rate, but a heterogeneity in response might not contribute to the difference. The neocarzinostatin-induced DNA damage were efficiently repaired in a dose-dependent fashion. The initial amount of gamma-ray induced DNA double-strand breaks was not significantly altered in cells pre-exposed to very low adapting dose. (author)

  2. The effects of over-expressing Tip60 on cellular DNA damage repair and cell cycle progression

    International Nuclear Information System (INIS)

    To investigate the effects of Tip60 on DNA damage repair, cell cycle and the related mechanism as well, the proliferative activity, DNA double strand break (DSB) repair competency and cell cycle arrest were analyzed in stable Tip60-overexpression U2OS cells established by transfecting with exogenous Tip60 gene. It was found that the overexpression of Tip60 inhibited the proliferative activity but increased the DNA damage repair competency. The radiation-induced G2/M arrest was prolonged in Tip60 over-expressed U2OS cells, which was associated with a decreasing level of cell cycle checkpoint protein Cyclin B/CDC2 complex. (authors)

  3. DNA DAMAGE REPAIR AND CELL CYCLE CONTROL: A NATURAL BIO-DEFENSE MECHANISM

    Science.gov (United States)

    DNA DAMAGE REPAIR AND CELL CYCLE CONTROL: A natural bio-defense mechanismAnuradha Mudipalli.Maintenance of genetic information, including the correct sequence of nucleotides in DNA, is essential for replication, gene expression, and protein synthesis. DNA lesions onto...

  4. Making Ends Meet: Myeloid Cells Catalyze Blood Vessel Repair in the Brain.

    Science.gov (United States)

    Deczkowska, Aleksandra; Schwartz, Michal

    2016-05-17

    Hemorrhagic stroke, primarily caused by rupture of blood vessels in the brain, is a leading cause of death and disability in adults. In this issue of Immunity, Liu et al. (2016) demonstrate that repair of cerebrovascular ruptures can be directly mediated by myeloid cells. PMID:27192572

  5. Expression of Delayed Cell Death and DNA Repair in Human Epithelial Cell Lines Following Exposure to Ultraviolet Radiation

    International Nuclear Information System (INIS)

    The long term effects of UVA and UVB have been investigated using two human epithelial cell lines, HTori-3 (a human thyroid epithelial cell line) and 340 RPE-T53 (a human retinal pigment epithelial cell line). There was a marked difference in clonogenic survival following exposure between the two cell lines. DNA repair studies were undertaken using ara-C treatment. Ara-C administered immediately after UVB exposure, reduced survival in both cell lines indicating that DNA repair was inhibited. The plating efficiency, as an index of delayed cell death of both cell lines measured up to 20 population doublings following exposure to UV was reduced in a dose dependent manner after exposure to UVB but not to UVA. (author)

  6. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    Science.gov (United States)

    Pretel, H.; Oliveira, J. A.; Lizarelli, R. F. Z.; Ramalho, L. T. O.

    2009-02-01

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI - only Ca(OH)2, GII - laser 688 nm, and GIII - laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p < 0.05) and between groups GI and GIII (p < 0.01). On 60th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm.

  7. Evaluation of dental pulp repair using low level laser therapy (688 nm and 785 nm) morphologic study in capuchin monkeys

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the hypothesis that low-level laser therapy (LLLT) 688 nm and 785 nm accelerate dentin barrier formation and repair process after traumatic pulp exposure. The sample consisted of 45 premolars of capuchin monkeys (Cebus apella) with pulp exposure Class V cavities. All premolars were treated with calcium hydroxide (Ca(OH)2), divided in groups of 15 teeth each, and analyzed on 7th, 25th, and 60th day. Group GI – only Ca(OH)2, GII – laser 688 nm, and GIII – laser 785 nm. Laser beam was used in single and punctual dose with the parameters: continuous, 688 nm and 785 nm wavelength, tip's area of 0.00785 cm2, power 50 mW, application time 20 s, dose 255 J/cm2, energy 2 J. Teeth were capped with Ca(OH)2, Ca(OH)2 cement and restored with amalgam. All groups presented pulp repair. On 25th day the thickness of the formed dentin barrier was different between the groups GI and GII (p th day there was difference between GI and GIII (p < 0.01). It may be concluded that, LLLT 688 nm and 785 nm accelerated dentin barrier formation and consequently pulp repair process, with best results using infrared laser 785 nm

  8. Radiation therapy for intracranial germ cell tumors

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Shingo; Hayakawa, Kazushige; Tsuchiya, Miwako; Arai, Masahiko; Kazumoto, Tomoko; Niibe, Hideo; Tamura, Masaru

    1988-04-01

    The results of radiation therapy in 31 patients with intracranial germ cell tumors have been analyzed. The five-year survival rates were 70.1 % for germinomas and 38.1 % for teratomas. Three patients with germinoma have since died of spinal seeding. The prophylactic irradiation of the spinal canal has been found effective in protecting spinal seeding, since no relapse of germinoma has been observed in cases that received entire neuraxis iradiation, whereas teratomas and marker (AFP, HCG) positive tumors did not respond favorably to radiation therapy, and the cause of death in these patients has been local failure. Long-term survivors over 3 years after radiation therapy have been determined as having a good quality of life.

  9. Radiation induced bystander signals are independent of DNA damage and DNA repair capacity of the irradiated cells

    International Nuclear Information System (INIS)

    Evidence is accumulating that irradiated cells produce signals, which interact with non-exposed cells in the same population. Here, we analysed the mechanism for bystander signal arising in wild-type CHO cells and repair deficient varients, focussing on the relationship between DNA repair capacity and bystander signal arising in irradiated cells. In order to investigate the bystander effect, we carried out medium transfer experiments after X-irradiation where micronuclei were scored in non-targeted DSB repair deficient xrs5 cells. When conditioned medium from irradiated cells was transferred to unirradiated xrs5 cells, the level of induction was independent of whether the medium came from irradiated wild-type, ssb or dsb repair deficient cells. This result suggests that the activation of a bystander signal is independent of the DNA repair capacity of the irradiated cells. Also, pre-treatment of the irradiated cells with 0.5% DMSO, which suppresses micronuclei induction in CHO but not in xrs5 cells, suppressed bystander effects completely in both conditioned media, suggesting that DMSO is effective for suppression of bystander signal arising independently of DNA damage in irradiated cells. Overall the work presented here adds to the understanding that it is the repair phenotype of the cells receiving bystander signals, which determines overall response rather than that of the cell producing the bystander signal

  10. Nanopolymers Delivery of the Bone Morphogenetic Protein-4 Plasmid to Mesenchymal Stem Cells Promotes Articular Cartilage Repair In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Junjun Shi

    2012-01-01

    Full Text Available The clinical application of viral vectors for gene therapy is limited for biosafety consideration. In this study, to promote articular cartilage repair, poly (lactic-co glycolic acid (PLGA nanopolymers were used as non-viral vectors to transfect rabbit mesenchymal stem cells (MSCs with the pDC316-BMP4-EGFP plasmid. The cytotoxicity and transfection efficiency in vitro were acceptable measuring by CCK-8 and flow cytometry. After transfection, Chondrogenic markers (mRNA of Col2a1, Sox9, Bmp4, and Agg of experimental cells (MSCs being transfected with BMP-4 plasmid by PLGA nanopolymers were increased more than those of control cells (MSCs being transfected with naked BMP-4 plasmid alone. In vivo study, twelve rabbits (24 knees with large full thickness articular cartilage defects were randomly divided into the experimental group (MSCs being transfected with BMP-4 plasmid by PLGA nanopolymers and the control group (MSCs being transfected with naked BMP-4 plasmid. The experimental group showed better regeneration than the control group 6 and 12 weeks postoperatively. Hyaline-like cartilage formed at week 12 in the experimental group, indicating the local delivery of BMP-4 plasmid to MSCs by PLGA nanopolymers improved articular cartilage repair significantly. PLGA nanopolymers could be a promising and effective non-viral vector for gene therapy in cartilage repair.

  11. RCC1-dependent activation of Ran accelerates cell cycle and DNA repair, inhibiting DNA damage-induced cell senescence.

    Science.gov (United States)

    Cekan, Pavol; Hasegawa, Keisuke; Pan, Yu; Tubman, Emily; Odde, David; Chen, Jin-Qiu; Herrmann, Michelle A; Kumar, Sheetal; Kalab, Petr

    2016-04-15

    The coordination of cell cycle progression with the repair of DNA damage supports the genomic integrity of dividing cells. The function of many factors involved in DNA damage response (DDR) and the cell cycle depends on their Ran GTPase-regulated nuclear-cytoplasmic transport (NCT). The loading of Ran with GTP, which is mediated by RCC1, the guanine nucleotide exchange factor for Ran, is critical for NCT activity. However, the role of RCC1 or Ran⋅GTP in promoting cell proliferation or DDR is not clear. We show that RCC1 overexpression in normal cells increased cellular Ran⋅GTP levels and accelerated the cell cycle and DNA damage repair. As a result, normal cells overexpressing RCC1 evaded DNA damage-induced cell cycle arrest and senescence, mimicking colorectal carcinoma cells with high endogenous RCC1 levels. The RCC1-induced inhibition of senescence required Ran and exportin 1 and involved the activation of importin β-dependent nuclear import of 53BP1, a large NCT cargo. Our results indicate that changes in the activity of the Ran⋅GTP-regulated NCT modulate the rate of the cell cycle and the efficiency of DNA repair. Through the essential role of RCC1 in regulation of cellular Ran⋅GTP levels and NCT, RCC1 expression enables the proliferation of cells that sustain DNA damage. PMID:26864624

  12. Repair and cell cycle response in cells exposed to environmental biohazards. Progress report, 1 June 1982-31 May 1983

    International Nuclear Information System (INIS)

    The research program has attempted to determine low environmental agents, especially ionizing radiation, interact with DNA and how the cells respond to the resulting damage. The focus has been on the spectrum of damage generated in DNA, the kinds of damage that can be repaired, and the mechanisms of repair. The effects of radioprotective agents and certain sensitizing conditions on breakage of DNA in bacterial cells by ionizing radiation, and mechanisms of enzymatic excision of pyrimidine dimers and other DNA adducts have been studied

  13. Cell-based and biomaterial approaches to connective tissue repair

    Science.gov (United States)

    Stalling, Simone Suzette

    Connective tissue injuries of skin, tendon and ligament, heal by a reparative process in adults, filling the wound site with fibrotic, disorganized scar tissue that poorly reflects normal tissue architecture or function. Conversely, fetal skin and tendon have been shown to heal scarlessly. Complete regeneration is not intrinsically ubiquitous to all fetal tissues; fetal diaphragmatic and gastrointestinal injuries form scars. In vivo studies suggest that the presence of fetal fibroblasts is essential for scarless healing. In the orthopaedic setting, adult anterior cruciate ligament (ACL) heals poorly; however, little is known about the regenerative capacity of fetal ACL or fetal ACL fibroblasts. We characterized in vitro wound healing properties of fetal and adult ACL fibroblasts demonstrating that fetal ACL fibroblasts migrate faster and elaborate greater quantities of type I collagen, suggesting the healing potential of the fetal ACL may not be intrinsically poor. Similar to fetal ACL fibroblasts, fetal dermal fibroblasts also exhibit robust cellular properties. We investigated the age-dependent effects of dermal fibroblasts on tendon-to-bone healing in rat supraspinatus tendon injuries, a reparative injury model. We hypothesized delivery of fetal dermal fibroblasts would increase tissue organization and mechanical properties in comparison to adult dermal fibroblasts. However, at 1 and 8 weeks, the presence of dermal fibroblasts, either adult or fetal, had no significant effect on tissue histology or mechanical properties. There was a decreasing trend in cross-sectional area of repaired tendons treated with fetal dermal fibroblasts in comparison to adult, but this finding was not significant in comparison to controls. Finally, we synthesized a novel polysaccharide, methacrylated methylcellulose (MA-MC), and fabricated hydrogels using a well-established photopolymerization technique. We characterized the physical and mechanical properties of MA-MC hydrogels in

  14. Red and Infrared Low-Level Laser Therapy Prior to Injury with or without Administration after Injury Modulate Oxidative Stress during the Muscle Repair Process

    OpenAIRE

    Ribeiro, Beatriz Guimarães; Alves, Agnelo Neves; dos Santos, Lucas Andreo Dias; Cantero, Tatiane Matarazzo; Fernandes, Kristianne Porta Santos; Dias, Danielle da Silva; Bernardes, Nathalia; De Angelis, Kátia; Mesquita-Ferrari, Raquel Agnelli

    2016-01-01

    Introduction Muscle injury is common among athletes and amateur practitioners of sports. Following an injury, the production of reactive oxygen species (ROS) occurs, which can harm healthy muscle fibers (secondary damage) and delay the repair process. Low-level laser therapy (LLLT) administered prior to or following an injury has demonstrated positive and protective effects on muscle repair, but the combination of both administration times together has not been clarified. Aim To evaluate the ...

  15. Mantle cell lymphoma: Frontline and salvage therapy.

    Science.gov (United States)

    Romaguera, Jorge E

    2008-10-01

    Mantle cell lymphoma (MCL) is a therapeutic challenge because of its lower cure rate when compared with other lymphomas such as diffuse large cell lymphoma. The current emphasis in the treatment of newly diagnosed MCL has been on intensifying chemotherapy, but there is no consensus on the need to consolidate with autologous stem cell transplantation. These approaches, however, have not resulted in a cure. Newer strategies include the use of models to aid in tailoring therapy. Likewise, autologous stem cell consolidation does not cure relapsed disease. Because of its known graft-versus-lymphoma effect, allogeneic stem cell transplantation offers a potentially curative option for relapsed MCL. New insights into resistance pathways and new drugs created to inhibit them offer great promise in the treatment of newly diagnosed and previously treated MCL. PMID:20425467

  16. Renal Preservation Therapy for Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Yichun Chiu

    2012-01-01

    Full Text Available Renal preservation therapy has been a promising concept for the treatment of localized renal cell carcinoma (RCC for 20 years. Nowadays partial nephrectomy (PN is well accepted to treat the localized RCC and the oncological control is proved to be the same as the radical nephrectomy (RN. Under the result of well oncological control, minimal invasive method gains more popularity than the open PN, like laparoscopic partial nephrectomy (LPN and robot assisted laparoscopic partial nephrectomy (RPN. On the other hand, thermoablative therapy and cryoablation also play an important role in the renal preservation therapy to improve the patient procedural tolerance. Novel modalities, but limited to small number of patients, include high-intensity ultrasound (HIFU, radiosurgery, microwave therapy (MWT, laser interstitial thermal therapy (LITT, and pulsed cavitational ultrasound (PCU. Although initial results are encouraging, their real clinical roles are still under evaluation. On the other hand, active surveillance (AS has also been advocated by some for patients who are unfit for surgery. It is reasonable to choose the best therapeutic method among varieties of treatment modalities according to patients' age, physical status, and financial aid to maximize the treatment effect among cancer control, patient morbidity, and preservation of renal function.

  17. Clustered DNA lesion repair in eukaryotes: Relevance to mutagenesis and cell survival

    International Nuclear Information System (INIS)

    A clustered DNA lesion, also known as a multiply damaged site, is defined as ≥2 damages in the DNA within 1-2 helical turns. Only ionizing radiation and certain chemicals introduce DNA damage in the genome in this non-random way. What is now clear is that the lethality of a damaging agent is not just related to the types of DNA lesions introduced, but also to how the damage is distributed in the DNA. Clustered DNA lesions were first hypothesized to exist in the 1990s, and work has progressed where these complex lesions have been characterized and measured in irradiated as well as in non-irradiated cells. A clustered lesion can consist of single as well as double strand breaks, base damage and abasic sites, and the damages can be situated on the same strand or opposing strands. They include tandem lesions, double strand break (DSB) clusters and non-DSB clusters, and base excision repair as well as the DSB repair pathways can be required to remove these complex lesions. Due to the plethora of oxidative damage induced by ionizing radiation, and the repair proteins involved in their removal from the DNA, it has been necessary to study how repair systems handle these lesions using synthetic DNA damage. This review focuses on the repair process and mutagenic consequences of clustered lesions in yeast and mammalian cells. By examining the studies on synthetic clustered lesions, and the effects of low vs high LET radiation on mammalian cells or tissues, it is possible to extrapolate the potential biological relevance of these clustered lesions to the killing of tumor cells by radiotherapy and chemotherapy, and to the risk of cancer in non-tumor cells, and this will be discussed.

  18. Clustered DNA lesion repair in eukaryotes: Relevance to mutagenesis and cell survival

    Energy Technology Data Exchange (ETDEWEB)

    Sage, Evelyne [Institut Curie, Bat. 110, Centre Universitaire, 91405 Orsay (France); CNRS UMR3348, Bat. 110, Centre Universitaire, 91405 Orsay (France); Harrison, Lynn, E-mail: lclary@lsuhsc.edu [Department of Molecular and Cellular Physiology, LSUHSC-S, 1501 Kings Highway, Shreveport, LA 71130 (United States)

    2011-06-03

    A clustered DNA lesion, also known as a multiply damaged site, is defined as {>=}2 damages in the DNA within 1-2 helical turns. Only ionizing radiation and certain chemicals introduce DNA damage in the genome in this non-random way. What is now clear is that the lethality of a damaging agent is not just related to the types of DNA lesions introduced, but also to how the damage is distributed in the DNA. Clustered DNA lesions were first hypothesized to exist in the 1990s, and work has progressed where these complex lesions have been characterized and measured in irradiated as well as in non-irradiated cells. A clustered lesion can consist of single as well as double strand breaks, base damage and abasic sites, and the damages can be situated on the same strand or opposing strands. They include tandem lesions, double strand break (DSB) clusters and non-DSB clusters, and base excision repair as well as the DSB repair pathways can be required to remove these complex lesions. Due to the plethora of oxidative damage induced by ionizing radiation, and the repair proteins involved in their removal from the DNA, it has been necessary to study how repair systems handle these lesions using synthetic DNA damage. This review focuses on the repair process and mutagenic consequences of clustered lesions in yeast and mammalian cells. By examining the studies on synthetic clustered lesions, and the effects of low vs high LET radiation on mammalian cells or tissues, it is possible to extrapolate the potential biological relevance of these clustered lesions to the killing of tumor cells by radiotherapy and chemotherapy, and to the risk of cancer in non-tumor cells, and this will be discussed.

  19. In vivo tracking for cell therapies

    International Nuclear Information System (INIS)

    The success of a particular cellular therapy regime requires the therapeutic agent to migrate expeditiously to the intended target in sufficient numbers and to provoke a desirable response. There are many variables associated with the production, administration and host that need to be investigated to maximize the resulting therapeutic benefit. The large number of factors which may contribute to, or detract from, treatment efficacy can make therapy optimization an arduous procedure. Direct visualization of in vivo migration patterns using nuclear medicine techniques greatly assists the appraisal of the multitude of variables. Conventional radionuclide cell labeling is a proven, simple and sensitive technique which can provide whole body biodistribution information. Labeling with a PET isotope offers greater sensitivity, much improved 3-dimensional resolution and quantification. In general, current efforts are increasingly concentrating on this technology. Imaging studies can supply definitive evidence of successful targeting and allow quantification of the degree of migration to a particular site. Incorporating tracking studies into clinical trials of cell-based therapy at the earliest stage can provide proof of mechanism of the therapy and permit evaluation of the many contributory variables, even on a patient-by-patient basis

  20. Cell therapies for pancreatic beta-cell replenishment.

    Science.gov (United States)

    Okere, Bernard; Lucaccioni, Laura; Dominici, Massimo; Iughetti, Lorenzo

    2016-01-01

    The current treatment approach for type 1 diabetes is based on daily insulin injections, combined with blood glucose monitoring. However, administration of exogenous insulin fails to mimic the physiological activity of the islet, therefore diabetes often progresses with the development of serious complications such as kidney failure, retinopathy and vascular disease. Whole pancreas transplantation is associated with risks of major invasive surgery along with side effects of immunosuppressive therapy to avoid organ rejection. Replacement of pancreatic beta-cells would represent an ideal treatment that could overcome the above mentioned therapeutic hurdles. In this context, transplantation of islets of Langerhans is considered a less invasive procedure although long-term outcomes showed that only 10 % of the patients remained insulin independent five years after the transplant. Moreover, due to shortage of organs and the inability of islet to be expanded ex vivo, this therapy can be offered to a very limited number of patients. Over the past decade, cellular therapies have emerged as the new frontier of treatment of several diseases. Furthermore the advent of stem cells as renewable source of cell-substitutes to replenish the beta cell population, has blurred the hype on islet transplantation. Breakthrough cellular approaches aim to generate stem-cell-derived insulin producing cells, which could make diabetes cellular therapy available to millions. However, to date, stem cell therapy for diabetes is still in its early experimental stages. This review describes the most reliable sources of stem cells that have been developed to produce insulin and their most relevant experimental applications for the cure of diabetes. PMID:27400873

  1. In vitro expression levels of cell-cycle checkpoint proteins are associated with cellular DNA repair capacity in peripheral blood lymphocytes: a multivariate analysis

    OpenAIRE

    Fan, You-Hong; Hu, Zhibin; Li, Chunying; Wang, Li-E; Guo, Zhaozheng; Qiao, Yawei; Zhang, Li; Zhang, Wei; Mao, Li; Wei, Qingyi

    2007-01-01

    DNA repair should occur after cells sense DNA damage signals and undergo cell-cycle arrest to provide sufficient time for DNA repair, and suboptimal DNA repair capacity (DRC) in peripheral lymphocytes has been suggested as a cancer susceptibility marker. Numerous studies showed a functional link between DNA damage sensing, cell-cycle checkpoint and DNA repair. We hypothesized that in vitro cell-cycle checkpoint-related protein expression levels in stimulated lymphocytes predict DRC levels. To...

  2. Optimization and standardization of the ''comet assay'' for analyzing the repair of DNA damage in cells

    International Nuclear Information System (INIS)

    Human tumor cells or isolated human peripheral blood lymphocytes were analyzed in the experiments. The amount of DNA damage and the effectiveness of DNA repair was measured after X-irradiation using the 'comet assay' technique. Results: In this presentation the influences of different methodological factors like agarose concentration, buffer pH, electrophoresis time, electric field strength on the applicability of the 'comet assay' are described in detail and optimum conditions for 'comet assay' experiments have been evaluated. Additionally the authors will show a comparison of different fluorescent DNA dyes pointing out their advantages or disadvantages for 'comet' analysis. The usefulness of this technique and its capabilities are exemplified by showing DNA repair kinetics of human lymphocytes of different healthy or radiosensitive donors after in-vitro irradiation with 2 Gy X-rays. Conclusions: This paper presents data on the optimization and standardization of the original 'comet assay' leading to an extremely fast and practicable protocol in the field of single cell gel electrophoresis. After irradiation with 0.1 Gy an increase in the amount of DNA damage can be measured with high statistical significance and the DNA repair capacity of individual cells after X-ray doses of 2 Gy can be analyzed with high reproducibility. The results comparing DNA repair capacities of different donors point out that the 'comet assay' may have the potential for the estimation of individual radiosensitivity. (orig./MG)

  3. A Chinese hamster ovary cell line hypersensitive to ionizing radiation and deficient in repair replication

    International Nuclear Information System (INIS)

    An X-ray-sensitive Chinese hamster ovary cell line was isolated by means of a semi-automated procedure in which mutagenized cells formed colonies on top of agar, were X-irradiated, and were photographed at two later times. The author compared the photographs to identify colonies that displayed significant growth arrest. One of the colonies identified in this manner produced a stable line (irs1SF) that is hypersensitive to ionizing radiation. irs1SF performs only half as much X-ray-induced repair replication as the parental line, indicating a defect in excision repair. This defect is believed to be the primary cause of the line's radiosensitivity. Although irs1SF repairs DNA double-strand breaks at a normal rate, it repairs single-strand breaks more slowly than normal. irs1SF has an elevated number of spontaneous chromatid aberrations and produces significantly higher numbers of X-ray-induced chromatid aberrations after exposure during the G1 phase of the cell cycle. The line is hypomutable, with X-ray exposure inducing only one-third as many 6-thioguanine-resistant colonies as the parental line. 45 refs.; 10 figs.; 1 table

  4. DNA Repair Gene Polymorphisms May Be Associated with Prognosis of Upper Urinary Tract Transitional Cell Carcinoma1

    OpenAIRE

    SASAKI, Miwa; Sakano, Shigeru; Okayama, Naoko; Akao, Jumpei; Hara, Tomohiko; Kawai, Yoshihisa; Ohmi, Chietaka; Hinoda, Yuji; Naito, Katsusuke

    2008-01-01

    Upper urinary tract transitional cell carcinoma (UUT-TCC) is quite an uncommon disease, and its prognosis differs among individuals irrespective of tumor stage. DNA repair gene polymorphisms are reported to result in the modulation of the repair capacity and might influence the prognosis of UUT-TCC. We examined the associations between functional polymorphisms in five DNA repair genes, and the prognosis of UUT-TCC in 103 UUT-TCC patients. Variant alleles in xeroderma pigmentosum complementati...

  5. A cell-free system for DNA repair synthesis using purified enzymes from the Novikoff hepatoma

    International Nuclear Information System (INIS)

    Novikoff DNA polymerase-β and Novikoff DNase V have been used in a cell-free DNA excision repair system for UV-irradiated substrates to determine their DNA repair capabilities. The repair system was shown to depend upon UV-irradiated DNA, incision by phage T4 UV-endonuclease, excision by DNase V and synthesis by DNA polymerase-β; ligation was not included. Highly purified calf thymus DNA was UV-irradiated at 500-750 J/m2 and incised by T4 UV-endonuclease. The repair system was used to follow the purification of DNase V and DNA polymerase-β. For increased specificity, the parameters of UV-irradiation, incision, excision and synthesis were confirmed on highly supercoiled, covalently closed, phage PM2 DNA. Optimal DNA and Mg2+ concentrations were determined for the repair assay, which was shown to be linear with respect to time. Excision of the 3'-apyrimidinic site and the 5'-pyrimidine dimer by bidirectional DNase V, presumed to occur from the above experiments, was studied more thoroughly using lightly UV-irradiated [3H]poly(dT)poly (dA), labeled in both the base and the sugar, and incised with T4 UV-endonuclease

  6. Cell Therapy for Diabetic Neuropathy Using Adult Stem or Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Ji Woong Han

    2013-04-01

    Full Text Available Diabetic neuropathy (DN is the most common and disabling complication of diabetes that may lead to foot ulcers and limb amputations. Despite widespread awareness of DN, the only effective treatments are glucose control and pain management. A growing body of evidence suggests that DN is characterized by reduction of vascularity in peripheral nerves and deficiency in neurotrophic and angiogenic factors. Previous studies have tried to introduce neurotrophic or angiogenic factors in the form of protein or gene for therapy, but the effect was not significant. Recent studies have shown that bone marrow (BM-derived stem or progenitor cells have favorable effects on the repair of cardiovascular diseases. Since these BM-derived stem or progenitor cells contain various angiogenic and neurotrophic factors, these cells have been attempted for treating experimental DN, and turned out to be effective for reversing various manifestations of experimental DN. These evidences suggest that cell therapy, affecting both vascular and neural components, can represent a novel therapeutic option for treatment of clinical DN.

  7. STAT3 signaling controls satellite cell expansion and skeletal muscle repair

    OpenAIRE

    Tierney, Matthew Timothy; Aydogdu, Tufan; Sala, David; Malecova, Barbora; Gatto, Sole; Puri, Pier Lorenzo; Latella, Lucia; Sacco, Alessandra

    2014-01-01

    The progression of disease- and age-dependent skeletal muscle wasting results in part from a decline in the number and function of satellite cells, the direct cellular contributors to muscle repair1–10. However, little is known about the molecular effectors underlying satellite cell impairment and depletion. Elevated levels of inflammatory cytokines, including interleukin-6 (IL-6), are associated with both age-related and muscle-wasting conditions11–13. The levels of STAT3, a downstream effec...

  8. Innate Lymphoid Cells: Balancing Immunity, Inflammation, and Tissue Repair in the Intestine

    OpenAIRE

    Wojno, Elia D. Tait; Artis, David

    2012-01-01

    Innate lymphoid cells (ILCs) are a recently described group of innate immune cells that can regulate immunity, inflammation, and tissue repair in multiple anatomical compartments, particularly the barrier surfaces of the skin, airways, and intestine. Broad categories of ILCs have been defined based on transcription factor expression and the ability to produce distinct patterns of effector molecules. Recent studies have revealed that ILC populations can regulate commensal bacterial communities...

  9. Tcf3 promotes cell migration and wound repair through regulation of lipocalin 2

    OpenAIRE

    Miao, Qi; Ku, Amy T.; Nishino, Yudai; Howard, Jeffrey M.; Rao, Ajay S.; Shaver, Timothy M.; Garcia, Gloria E.; Le, Diep N.; Karlin, Kristen L; Westbrook, Thomas F.; Poli, Valeria; Nguyen, Hoang

    2014-01-01

    Cell migration is an integral part of re-epithelialization during skin wound healing, a complex process involving molecular controls that are still largely unknown. Here we identify a novel role for Tcf3, an essential transcription factor regulating embryonic and adult skin stem cell functions, as a key effector of epidermal wound repair. We show that Tcf3 is upregulated in skin wounds and that Tcf3 overexpression accelerates keratinocyte migration and skin wound healing. We also identify Sta...

  10. Substrate-mediated reprogramming of human fibroblasts into neural crest stem-like cells and their applications in neural repair.

    Science.gov (United States)

    Tseng, Ting-Chen; Hsieh, Fu-Yu; Dai, Niann-Tzyy; Hsu, Shan-Hui

    2016-09-01

    Cell- and gene-based therapies have emerged as promising strategies for treating neurological diseases. The sources of neural stem cells are limited while the induced pluripotent stem (iPS) cells have risk of tumor formation. Here, we proposed the generation of self-renewable, multipotent, and neural lineage-related neural crest stem-like cells by chitosan substrate-mediated gene transfer of a single factor forkhead box D3 (FOXD3) for the use in neural repair. A simple, non-toxic, substrate-mediated method was applied to deliver the naked FOXD3 plasmid into human fibroblasts. The transfection of FOXD3 increased cell proliferation and up-regulated the neural crest marker genes (FOXD3, SOX2, and CD271), stemness marker genes (OCT4, NANOG, and SOX2), and neural lineage-related genes (Nestin, β-tubulin and GFAP). The expression levels of stemness marker genes and neural crest maker genes in the FOXD3-transfected fibroblasts were maintained until the fifth passage. The FOXD3 reprogrammed fibroblasts based on the new method significantly rescued the neural function of the impaired zebrafish. The chitosan substrate-mediated delivery of naked plasmid showed feasibility in reprogramming somatic cells. Particularly, the FOXD3 reprogrammed fibroblasts hold promise as an easily accessible cellular source with neural crest stem-like behavior for treating neural diseases in the future. PMID:27341268

  11. Renal Preservation Therapy for Renal Cell Carcinoma

    OpenAIRE

    Yichun Chiu; Allen W. Chiu

    2012-01-01

    Renal preservation therapy has been a promising concept for the treatment of localized renal cell carcinoma (RCC) for 20 years. Nowadays partial nephrectomy (PN) is well accepted to treat the localized RCC and the oncological control is proved to be the same as the radical nephrectomy (RN). Under the result of well oncological control, minimal invasive method gains more popularity than the open PN, like laparoscopic partial nephrectomy (LPN) and robot assisted laparoscopic partial nephrectomy...

  12. Targeted therapy for metastatic renal cell carcinoma

    OpenAIRE

    Patel, P H; Chaganti, R.S.K.; Motzer, R J

    2006-01-01

    Metastatic renal cell carcinoma (RCC) has historically been refractory to cytotoxic and hormonal agents; only interleukin 2 and interferon alpha provide response in a minority of patients. We reviewed RCC biology and explored the ways in which this understanding led to development of novel, effective targeted therapies. Small molecule tyrosine kinase inhibitors, monoclonal antibodies and novel agents are all being studied, and phase II studies show promising activity of sunitinib, sorafenib a...

  13. Stem Cell Therapy for Heart Disease

    OpenAIRE

    Puliafico, Shannon B.; Penn, Marc S.; Silver, Kevin H.

    2013-01-01

    Coronary artery disease is the leading cause of death in Americans. After myocardial infarction, significant ventricular damage persists despite timely reperfusion and pharmacological management. Treatment is limited, as current modalities do not cure this damage. In the past decade, stem cell therapy has emerged as a promising therapeutic solution to restore myocardial function. Clinical trials have demonstrated safety and beneficial effects in patients suffering from acute myocardial infarc...

  14. Stem cell therapy: A challenge to periodontist

    OpenAIRE

    Jayashree A Mudda; Monika Bajaj

    2011-01-01

    Periodontitis is an inflammatory disease which manifests clinically as loss of supporting periodontal tissues including periodontal ligament, cementum, and alveolar bone, and periodontal therapy is aimed at achieving complete regeneration of these structures. To date, this goal has been tried to accomplish using various bone grafts, growth factors, and barrier membranes. Stem cells are the most fascinating area of biology today and have been used clinically in the field of medicine to treat m...

  15. Meta-Analyses of Human Cell-Based Cardiac Regeneration Therapies: What Can Systematic Reviews Tell Us About Cell Therapies for Ischemic Heart Disease?

    Science.gov (United States)

    Martin-Rendon, Enca

    2016-04-15

    Controversies from basic science, discrepancies from clinical trials, and divergent results from meta-analyses have recently arisen in the field of cell therapies for cardiovascular repair and regeneration. Noticeably, there are almost as many systematic reviews and meta-analyses published as there are well-conducted clinical studies. But how do we disentangle the confusion they have raised? This article addresses why results obtained from systematic reviews and meta-analyses of human cell-based cardiac regeneration therapies are still valid to inform the design of future clinical trials. It also addresses how meta-analyses are not free from limitations and how important it is to assess the quality of the evidence and the quality of the systematic reviews and finally how stronger conclusions can be drawn when several pieces of evidence converge. PMID:27081109

  16. PET imaging of adoptive progenitor cell therapies.

    Energy Technology Data Exchange (ETDEWEB)

    Gelovani, Juri G.

    2008-05-13

    Objectives. The overall objective of this application is to develop novel technologies for non-invasive imaging of adoptive stem cell-based therapies with positron emission tomography (PET) that would be applicable to human patients. To achieve this objective, stem cells will be genetically labeled with a PET-reporter gene and repetitively imaged to assess their distribution, migration, differentiation, and persistence using a radiolabeled reporter probe. This new imaging technology will be tested in adoptive progenitor cell-based therapy models in animals, including: delivery pro-apoptotic genes to tumors, and T-cell reconstitution for immunostimulatory therapy during allogeneic bone marrow progenitor cell transplantation. Technical and Scientific Merits. Non-invasive whole body imaging would significantly aid in the development and clinical implementation of various adoptive progenitor cell-based therapies by providing the means for non-invasive monitoring of the fate of injected progenitor cells over a long period of observation. The proposed imaging approaches could help to address several questions related to stem cell migration and homing, their long-term viability, and their subsequent differentiation. The ability to image these processes non-invasively in 3D and repetitively over a long period of time is very important and will help the development and clinical application of various strategies to control and direct stem cell migration and differentiation. Approach to accomplish the work. Stem cells will be genetically with a reporter gene which will allow for repetitive non-invasive “tracking” of the migration and localization of genetically labeled stem cells and their progeny. This is a radically new approach that is being developed for future human applications and should allow for a long term (many years) repetitive imaging of the fate of tissues that develop from the transplanted stem cells. Why the approach is appropriate. The novel approach to

  17. PET imaging of adoptive progenitor cell therapies

    International Nuclear Information System (INIS)

    The overall objective of this application is to develop novel technologies for non-invasive imaging of adoptive stem cell-based therapies with positron emission tomography (PET) that would be applicable to human patients. To achieve this objective, stem cells will be genetically labeled with a PET-reporter gene and repetitively imaged to assess their distribution, migration, differentiation, and persistence using a radiolabeled reporter probe. This new imaging technology will be tested in adoptive progenitor cell-based therapy models in animals, including: delivery pro-apoptotic genes to tumors, and T-cell reconstitution for immunostimulatory therapy during allogeneic bone marrow progenitor cell transplantation. Technical and Scientific Merits. Non-invasive whole body imaging would significantly aid in the development and clinical implementation of various adoptive progenitor cell-based therapies by providing the means for non-invasive monitoring of the fate of injected progenitor cells over a long period of observation. The proposed imaging approaches could help to address several questions related to stem cell migration and homing, their long-term viability, and their subsequent differentiation. The ability to image these processes non-invasively in 3D and repetitively over a long period of time is very important and will help the development and clinical application of various strategies to control and direct stem cell migration and differentiation. Approach to accomplish the work. Stem cells will be genetically with a reporter gene which will allow for repetitive non-invasive 'tracking' of the migration and localization of genetically labeled stem cells and their progeny. This is a radically new approach that is being developed for future human applications and should allow for a long term (many years) repetitive imaging of the fate of tissues that develop from the transplanted stem cells. Why the approach is appropriate. The novel approach to stem cell imaging

  18. Concise Review: Stem Cell Therapy for Muscular Dystrophies

    OpenAIRE

    Wilschut, Karlijn J.; Ling, Vivian B.; Bernstein, Harold S.

    2012-01-01

    Stem cell therapy holds promise as a treatment for muscular dystrophy by providing cells that can both deliver functional muscle proteins and replenish the stem cell pool. This article reviews the current state of research on myogenic stem cells and identifies the important challenges that must be addressed as stem cell therapy is brought to the clinic.

  19. Heterogeneous Stem Cells in Skin Homeostatis and Wound Repair

    Directory of Open Access Journals (Sweden)

    Anna Meilana

    2015-08-01

    Full Text Available BACKGROUND: The skin protects mammals from insults, infection and dehydration and enables thermoregulation and sensory perception. Various skin-resident cells carry out these diverse functions. Constant turnover of cells and healing upon injury necessitate multiple reservoirs of stem cells. The skin is a complex organ harboring several distinct populations of stem cells and a rich array of cell types. Advances in genetic and imaging tools have brought new findings about the lineage relationships between skin stem cells and their progeny. Such knowledge may offer novel avenues for therapeutics and regenerative medicine. CONTENT: In the past years, our view of the mechanisms that govern skin homeostasis and regeneration have markedly changed. New populations of stem cells have been identified that behave spatio-temporally differently in healthy tissues and in situations of damage, indicating that a great level of stem cell heterogeneity is present in the skin. There are believed to be distinct populations of stem cells in different locations. The lineages that they feed are normally constrained by signals from their local environment, but they can give rise to all epidermal lineages in response to appropriate stimuli. Given the richness of structures such as blood vessels, subcutaneous fat, innervation and the accumulation of fibroblasts under the upper parts of the rete ridges (in the case of human skin, it is reasonable to speculate that the microenvironment might be essential for interfollicular epidermal homeostasis. The bloodstream is probably the main source of long-range signals reaching the skin, and cues provided by the vascular niche might be essential for skin homeostasis. SUMMARY: A key function of the interfollicular epidermis is to act as a protective interface between the body and the external environment, and it contains several architectural elements that enable it to fulfill this function. All elements of the epidermis play

  20. Quantitative aspects of repair of potentially lethal damage in mammalian cells

    International Nuclear Information System (INIS)

    Stationary cultures of Ehrlich ascites tumour cells were irradiated with X-rays and then immediately or after a time interval tsub(rep) plated to measure the survival. The increase in survival observed after delayed plating was interpreted as repair of potentially lethal damage. A cybernetic model was used to analyse these data. Three states of damage were assumed for the cells. In state A the cells could grow to macrocolonies, in state B the cells suffered potentially lethal damage and could grow to macrocolonies only if they were allowed to repair the damage and in state C the cells were lethally damaged. A method of deriving the values of the parameters of the model from the experimental data was given. The dependence of the reaction rate constant of the repair potentially lethal damage on the dose D was used to derive a possible mechanism for the production of the shoulder in the dose effect curve. Finally this model was compared with other models of radiation action in living cells. (author)

  1. Single-cell gel electrophoresis applied to the analysis of UV-C damage and its repair in human cells

    International Nuclear Information System (INIS)

    The authors have adapted procedure of single cell gel electrophoresis (SCGE) for studying DNA damage and repair induced by UV-C-radiation, using HeLa cells. UV-C itself does not induce DNA breakage, and though cellular repair of UV-C damage produces DNA breaks as intermediates, these are too short-lived to be detected by SCGE. Incubation of UV-C-irradiated cells with the DNA synthesis inhibitor aphidicolin causes accumulation of incomplete repair sites to a level readily detected by SCGE even after doses as low as 0.5 J m-2 and incubation for as little as 5 min. The authors also studied UV-C-dependent incision, repair synthesis and ligation in permeable cells. Finally, key incubated permeable cells, after UV-C-irradiation, with exogenous UV endonuclease, examined consequent breaks both by SCGE and by alkaline unwinding to express results of the electrophoretic method in terms of DNA break frequencies. The sensitivity of the SCGE technique can thus be estimated; as few as 0.1 DNA breaks per 109 daltons are detected. (Author)

  2. Muscling up damaged hearts through cell therapy

    Institute of Scientific and Technical Information of China (English)

    Chi Van Dang

    2006-01-01

    @@ Molecular and cellular processes gleaned from the most fundamental of biomedical studies are now harnessed for their potential healing properties. In the US and throughout the world, millions of patients suffer from myocardial infarction and many succumb to the morbidity and mortality of the ensuing cardiac failure, a protracted condition in need of healing. While pharmacological agents have been the mainstay intervention that ameliorates cardiac failure through increased contractility or reduction of cardiac workload, these agents do not inherently heal the wounds inflicted by poor perfusion of the affected cardiac tissue.Cell therapy, however, holds the promise of repleting the damage heart with new contractile cells that can be engineered to secrete concoctions that promote healing by recruiting new blood vessel development or angiogenesis.Such cell therapeutic promise has already been fulfilled for many decades for hematological diseases through transplantation of bone marrow stem cells, which are now more broadly implicated for their healing potential of other tissues.

  3. Axonal outgrowth is associated with increased ERK 1/2 activation but decreased caspase 3 linked cell death in Schwann cells after immediate nerve repair in rats

    Directory of Open Access Journals (Sweden)

    Kanje Martin

    2011-01-01

    Full Text Available Abstract Background Extracellular-signal regulated kinase (ERK1/2 is activated by nerve damage and its activation precedes survival and proliferation of Schwann cells. In contrast, activation of caspase 3, a cysteine protease, is considered as a marker for apoptosis in Schwann cells. In the present study, axonal outgrowth, activation of ERK1/2 by phosphorylation (p-ERK 1/2 and immunoreactivity of cleaved caspase 3 were examined after immediate, delayed, or no repair of transected rat sciatic nerves. Results Axonal outgrowth, detected by neurofilament staining, was longer after immediate repair than after either the delayed or no repair conditions. Immediate repair also showed a higher expression of p-ERK 1/2 and a lower number of cleaved caspase 3 stained Schwann cells than after delayed nerve repair. If the transected nerve was not repaired a lower level of p-ERK 1/2 was found than in either the immediate or delayed repair conditions. Axonal outgrowth correlated to p-ERK 1/2, but not clearly with cleaved caspase 3. Contact with regenerating axons affected Schwann cells with respect to p-ERK 1/2 and cleaved caspase 3 after immediate nerve repair only. Conclusion The decreased regenerative capacity that has historically been observed after delayed nerve repair may be related to impaired activation of Schwann cells and increased Schwann cell death. Outgrowing axons influence ERK 1/2 activation and apoptosis of Schwann cells.

  4. Investigation progress of imaging techniques monitoring stem cell therapy

    International Nuclear Information System (INIS)

    Recently stem cell therapy has showed potential clinical application in diabetes mellitus, cardiovascular diseases, malignant tumor and trauma. Efficient techniques of non-invasively monitoring stem cell transplants will accelerate the development of stem cell therapies. This paper briefly reviews the clinical practice of stem cell, in addition, makes a review of monitoring methods including magnetic resonance and radionuclide imaging which have been used in stem cell therapy. (authors)

  5. Stem cells--potential for repairing damaged lungs and growing human lungs for transplant.

    Science.gov (United States)

    Bishop, Anne E; Rippon, Helen J

    2006-08-01

    Repair or regeneration of defective lung epithelium would be of great therapeutic potential. It is estimated by the British Lung Foundation that 1 in 7 people in the UK is affected by a lung disease and that 1 in 4 admissions to children's wards are as a result of respiratory problems. Potential cellular sources for the regeneration of lung tissue in vivo or lung tissue engineering in vitro include endogenous pulmonary epithelial stem cells, extrapulmonary circulating stem cells and embryonic stem cells. This article discusses the potential role of each of these stem cell types in future approaches to the treatment of lung injury and disease. PMID:16856797

  6. Drug delivery technologies and stem cells for tissue repair and regeneration.

    Science.gov (United States)

    Orive, Gorka; Cobos, Raquel; Gorriti, Janire; Pedraz, Jose L; Meregalli, Mirella; Torrente, Yvan

    2015-01-01

    In the last few years several technologies are being developed for eventually repairing or replacing damaged or injured tissues and even organs. Some of these emerging technologies include the design and development of new biomaterials, the optimization of nano- and micro-technologies for drug and cell delivery, the use of autologous proteins or the application of stem cells as therapeutics. Thus, several types of stem cells, e.g. ESCs, iPSCs, MSCs, CD133+ stem cells are being evaluated for tissue regeneration purposes. The present review describes some of these emerging technologies and discusses their potential benefits and challenges. PMID:25934974

  7. [Recruitment of osteogenic cells to bone formation sites during development and fracture repair - German Version].

    Science.gov (United States)

    Böhm, A-M; Dirckx, N; Maes, C

    2016-04-01

    Recruitment of osteoblast lineage cells to their bone-forming locations is essential for skeletal development and fracture healing. In developing bones, osteoprogenitor cells invade the cartilage mold to establish the primary ossification center. Similarly, osteogenic cells infiltrate and populate the callus tissue that is formed following an injury. Proper bone development and successful fracture repair must, therefore, rely on controlled temporal and spatial navigation cues guiding the cells to the sites where new bone formation is needed. Some cellular mechanisms and molecular pathways involved have been elucidated. PMID:27003859

  8. The role of stem cells in airway repair: implications for the origins of lung cancer

    OpenAIRE

    Mulvihill, Michael S.; Kratz, Johannes R.; Patrick Pham; Jablons, David M.; Biao He

    2013-01-01

    Lung cancer is the leading cause of cancer-related deaths worldwide. Recently, advancements in our ability to identify and study stem cell populations in the lung have helped researchers to elucidate the central role that cells with stem cell-like properties may have in lung tumorigenesis. Much of this research has focused on the use of the airway repair model to study response to injury. In this review, we discuss the primary evidence of the role that cancer stem cells play in lung cancer de...

  9. Comparative study of the effects of low-intensity pulsed ultrasound and low-level laser therapy on injured muscle repair

    Science.gov (United States)

    Renno, Ana Claudia Muniz; Toma, Renata Luri; Feitosa, Suellen Maurin; Fernandes, Kelly; de Oliveira, Poliani; Parizotto, N.; Ribeiro, Daniel Araki

    2011-03-01

    Muscle tissue is one of the most frequently affected by injury, whether during sports activities, or work activities. In this context, biochemical and biophysical resources have been studied to minimize the time of muscle regeneration. Among these, low intensity pulsed ultrasound (US) and low level laser therapy (LLLT) may be highlighted. Despite a series of evidences about the positive effects of these resources in the process of tissue regeneration, the cellular and morphological changes triggered by LLLT and U.S. are still largely unknown. Thus, the aim of this study was to investigate the effects of US and LLLT on muscle repair after cryolesion by means of histopathological analysis and immunohistochemistry for COX-2. A total of thirty five male Wistar rats were randomly distributed into 4 groups: intact control group; injured control group: muscle injured animals without any treatment; laser treated group: muscle injured animals treated with 830 nm laser and ultra-sound treated group: muscle injured animals treated with US. The treatments started 24 hours post-surgery and were performed during 6 sessions. The animals exposed to lasertherapy pointed out minor degenerative changes of muscle tissue. In the same way, exposure to ultrasound was able to reduce tissue injuries induced by cryolesion, but less intense than laser therapy. Strong COX-2 positive cells were found in rats submitted to cryolesion only, whereas COX-2 immunoexpression was lower in laser treated or ultrasound treated groups. In summary, this study reveals that both lasertherapy and ultrasound have positive effects on muscle repair in rats.

  10. Mesenchymal stromal cells for cardiovascular repair: current status and future challenges

    DEFF Research Database (Denmark)

    Mathiasen, Anders Bruun; Haack-Sørensen, Mandana; Kastrup, Jens

    2009-01-01

    results of most studies are promising, but there are still many unanswered questions. In this review, we explore present preclinical and clinical knowledge regarding the use of stem cells in cardiovascular regenerative medicine, with special focus on mesenchymal stromal cells. We take a closer look at...... for regenerative therapy. Clinical studies on stem cell therapy for cardiac regeneration have shown significant improvements in ventricular pump function, ventricular remodeling, myocardial perfusion, exercise potential and clinical symptoms compared with conventionally treated control groups. The...

  11. Wound repair and anti-oxidative capacity is regulated by ITGB4 in airway epithelial cells.

    Science.gov (United States)

    Liu, Chi; Liu, Hui-jun; Xiang, Yang; Tan, Yu-rong; Zhu, Xiao-lin; Qin, Xiao-qun

    2010-08-01

    Integrin beta 4 (ITGB4) is a structural adhesion molecule which engages in maintaining the integrity of airway epithelial cells. Its specific cytomembrane structural feature strongly indicates that ITGB4 may engage in many signaling pathways and physiologic processes. However, in addition to adhesion, the specific biologic significance of ITGB4 in airway epithelial cells is almost unknown. In this article, we investigated the expression and functional properties of ITGB4 in airway epithelial cells in vivo and in vitro. Human bronchial epithelial cell line (16HBE14O-cells) and primary rat tracheal epithelial cells (RTE cells) were used to determine ITGB4 expression under ozone tress or mechanical damage, respectively. An ovalbumin (OVA)-challenged asthma model was used to investigate ITGB4 expression after antigen exposure in vivo. In addition, an ITGB4 overexpression vector and ITGB4 silence virus vector were constructed and transfected into RTE cells. Then, wound repair ability and anti-oxidation capacity was evaluated. Our results demonstrated that, on the edge of mechanically wounded cell areas, ITGB4 expression was increased after mechanical injury. After ozone stress, upregulation expression of ITGB4 was also detected. In the OVA-challenged asthma model, ITGB4 expression was decreased on airway epithelial cells accompanying with structural disruption and damage of anti-oxidation capacity. Besides, our study revealed that upregulation of ITGB4 promotes wound repair ability and anti-oxidative ability, while such abilities were blocked when ITGB4 was silenced. Taken together, these results showed that ITGB4 was a new interesting molecule involved in the regulation of wound repair and anti-oxidation processes for airway epithelial cells. PMID:20364299

  12. New Insights into Diabetes Cell Therapy.

    Science.gov (United States)

    Lysy, Philippe A; Corritore, Elisa; Sokal, Etienne M

    2016-05-01

    Since insulin discovery, islet transplantation was the first protocol to show the possibility to cure patients with type 1 diabetes using low-risk procedures. The scarcity of pancreas donors triggered a burst of studies focused on the production of new β cells in vitro. These were rapidly dominated by pluripotent stem cells (PSCs) demonstrating diabetes-reversal potential in diabetic mice. Subsequent enthusiasm fostered a clinical trial with immunoisolated embryonic-derived pancreatic progenitors. Yet safety is the Achilles' heel of PSCs, and a whole branch of β cell engineering medicine focuses on transdifferentiation of adult pancreatic cells. New data showed the possibility to chemically stimulate acinar or α cells to undergo β cell neogenesis and provide opportunities to intervene in situ without the need for a transplant, at least after weighing benefits against systemic adverse effects. The current studies suggested the pancreas as a reservoir of facultative progenitors (e.g., in the duct lining) could be exploited ex vivo for expansion and β cell differentiation in timely fashion and without the hurdles of PSC use. Diabetes cell therapy is thus a growing field not only with great potential but also with many pitfalls to overcome for becoming fully envisioned as a competitor to the current treatment standards. PMID:26983626

  13. Postreplication repair: questions of its definition and possible alteration in xeroderma pigmentosum cell strains

    International Nuclear Information System (INIS)

    DNA synthesis in normal cells and in excision-defective and variant xeroderma pigmentosum cells was investigated after irradiation with ultraviolet light. The sizes of DNA synthesized during brief pulses of [3H]thymidine 1 to 2 h after irradiation were decreased, the xeroderma pigmentosum variant showing the smallest molecular weight. Once synthesized, however, labeled DNA increased in size at the same rate as control in all cell strains, and the rate was relatively insensitive to caffeine. After 2 to 3 h, labeled DNA in each cell type reached a maximum size that was less than that in control cells, indicating the presence of long-lived blocks to DNA chain growth. This kind of experiment (pulse-chase) has in the past been used to investigate a repair process believed to be associated with the bypass of damaged sites in parental DNA: postreplication repair. We present an alternative model that does not involve a specific postreplication repair mechanism, but involves normal chain elongation and termination mechanisms in which we conceive that dimers and other damaged sites act as all-or-nothing blocks to the progress of replication forks. No evidence could be found for any inducible process that enhanced the bypass of damaged sites

  14. Bone marrow-derived endothelial progenitor cells are involved in aneurysm repair in rabbits.

    Science.gov (United States)

    Fang, Xinggen; Zhao, Rui; Wang, Kuizhong; Li, Zifu; Yang, Penfei; Huang, Qinghai; Xu, Yi; Hong, Bo; Liu, Jianmin

    2012-09-01

    Endothelial progenitor cells (EPC) are believed to be involved in aneurysmal repair and remodeling. The aim of this study was to test this hypothesis and, if true, explore how EPC contribute to aneurysm repair in a rabbit model of elastase-induced carotid aneurysm. Rabbits were divided randomly into an in situ carotid EPC transfusion group (ISCT group, n=5), and an intravenous EPC transfusion group (IVT group, n=5). Autologous EPC were double-labeled with Hoechst 33342 and 5,6-carboxyfluorescein diacetate succinimidyl ester before injection into the animals in either the carotid artery (ISCT group) or marginal ear veins (IVT group). Three weeks later, labeled cells in the aneurysms were observed with respect to location, adhesion, and growth to detect signs of aneurysm repair. Labeled EPC were detected within the neointima in all five aneurysms in the ISCT group and in three of the five aneurysms in the IVT group, but there was no endothelial growth in the aneurysmal neointima in either group. These results show that bone marrow-derived EPC are involved in the process of aneurysm repair in this rabbit model. PMID:22789632

  15. Excision repair of ultraviolet-irradiated deoxyribonucleic acid in plasmolyzed cells of Escherichia coli

    International Nuclear Information System (INIS)

    A system of cells made permeable by treatment with high concentrations of sucrose (plasmolysis) has been exploited to study the excision repair of ultraviolet-irradiated deoxyribonucleic acid in Escherichia coli. It is demonstrated that adenosine 5'-triphosphate is required for incision breaks to be made in the bacterial chromosome as well as in covalently closed bacteriophage lambda deoxyribonucleic acid. After plasmolysis, uvrC mutant strains appear as defective in the incision step as the uvrA-mutated strains. This is in contrast to the situation in intact cells where uvrC mutants accumulate single-strand breaks during postirradiation incubation. These observations have led to the proposal of a model for excision repair, in which the ultraviolet-specific endonuclease, coded for by the uvrA and uvrB genes, exists in a complex with the uvrC gene product. The complex is responsible for the incision and possibly also the excision steps of repair. The dark-repair inhibitors acriflavine and caffeine are both shown to interfere with the action of the adenosine 5'-triphosphate-dependent enzyme

  16. DNA repair

    International Nuclear Information System (INIS)

    In this chapter a series of DNA repair pathways are discussed which are available to the cell to cope with the problem of DNA damaged by chemical or physical agents. In the case of microorganisms our knowledge about the precise mechanism of each DNA repair pathway and the regulation of it has been improved considerably when mutants deficient in these repair mechanisms became available. In the case of mammalian cells in culture, until recently there were very little repair deficient mutants available, because in almost all mammalian cells in culture at least the diploid number of chromosomes is present. Therefore the frequency of repair deficient mutants in such populations is very low. Nevertheless because replica plating techniques are improving some mutants from Chinese hamsters ovary cells and L5178Y mouse lymphoma cells are now available. In the case of human cells, cultures obtained from patients with certain genetic diseases are available. A number of cells appear to be sensitive to some chemical or physical mutagens. These include cells from patients suffering from xeroderma pigmentosum, Ataxia telangiectasia, Fanconi's anemia, Cockayne's syndrome. However, only in the case of xeroderma pigmentosum cells, has the sensitivity to ultraviolet light been clearly correlated with a deficiency in excision repair of pyrimidine dimers. Furthermore the work with strains obtained from biopsies from man is difficult because these cells generally have low cloning efficiencies and also have a limited lifespan in vitro. It is therefore very important that more repair deficient mutants will become available from established cell lines from human or animal origin

  17. The Hematopoietic Stem Cell Therapy for Exploration of Space

    Science.gov (United States)

    Ohi, S.

    Departments of Biochemistry &Molecular Biology, Genetics &Human Genetics, Pediatrics &Child Long-duration space missions require countermeasures against severe/invasive disorders in astronauts that are caused by space environments, such as hematological/cardiac abnormalities, bone/muscle losses, immunodeficiency, neurological disorders, and cancer. Some, if not all, of these disorders may be amenable to hematopoietic stem cell therapy and gene therapy. Growing evidence indicates that hematopoietic stem cells (HSCs) possess extraordinary plasticity to differentiate not only to all types of blood cells but also to various tissues, including bone, muscle, skin, liver and neuronal cells. Therefore, our working hypothesis is that the hematopoietic stem cell-based therapy, herein called as the hematopoietic stem cell therapy (HSCT), might provide countermeasure/prevention for hematological abnormalities, bone and muscle losses in space, thereby maintaining astronauts' homeostasis. Our expertise lies in recombinant adeno-associated virus (rAAV)-mediated gene therapy for the hemoglobinopathies, -thalassemia and sickle cell disease (Ohi S, Kim BC, J Pharm Sci 85: 274-281, 1996; Ohi S, et al. Grav Space Biol Bull 14: 43, 2000). As the requisite steps in this protocol, we established procedures for purification of HSCs from both mouse and human bone marrow in 1 G. Furthermore, we developed an easily harvestable, long-term liquid suspension culture system, which lasts more than one year, for growing/expanding HSCs without stromal cells. Human globin cDNAs/gene were efficiently expressed from the rAAVs in the mouse HSCs in culture. Additionally, the NASA Rotating Wall Vessel (RWV) culture system is being optimized for the HSC growth/expansion. Thus, using these technologies, the above hypothesis is being investigated by the ground-based experiments as follows: 1) -thalassemic mice (C57BL/6-Hbbth/Hbbth, Hbd-minor) are transplanted with normal isologous HSCs to correct the

  18. Helicobacter pylori Disrupts Host Cell Membranes, Initiating a Repair Response and Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Hsueh-Fen Juan

    2012-08-01

    Full Text Available Helicobacter pylori (H. pylori, the human stomach pathogen, lives on the inner surface of the stomach and causes chronic gastritis, peptic ulcer, and gastric cancer. Plasma membrane repair response is a matter of life and death for human cells against physical and biological damage. We here test the hypothesis that H. pylori also causes plasma membrane disruption injury, and that not only a membrane repair response but also a cell proliferation response are thereby activated. Vacuolating cytotoxin A (VacA and cytotoxin-associated gene A (CagA have been considered to be major H. pylori virulence factors. Gastric cancer cells were infected with H. pylori wild type (vacA+/cagA+, single mutant (ΔvacA or ΔcagA or double mutant (ΔvacA/ΔcagA strains and plasma membrane disruption events and consequent activation of membrane repair components monitored. H. pylori disrupts the host cell plasma membrane, allowing localized dye and extracellular Ca2+ influx. Ca2+-triggered members of the annexin family, A1 and A4, translocate, in response to injury, to the plasma membrane, and cell surface expression of an exocytotic maker of repair, LAMP-2, increases. Additional forms of plasma membrane disruption, unrelated to H. pylori exposure, also promote host cell proliferation. We propose that H. pylori activation of a plasma membrane repair is pro-proliferative. This study might therefore provide new insight into potential mechanisms of H. pylori-induced gastric carcinogenesis.

  19. Transcription-coupled nucleotide excision repair in mammalian cells: molecular mechanisms and biological effects

    Institute of Scientific and Technical Information of China (English)

    Mafia Fousteri; Leon HF Mullenders

    2008-01-01

    The encounter of elongating RNA polymerase Ⅱ (RNAPIIo) with DNA lesions has severe consequences for the cell as this event provides a strong signal for P53-dependent apoptosis and cell cycle arrest. To counteract prolonged blockage of transcription, the cell removes the RNAPllo-hlocking DNA lesions by transcription-coupled repair (TC-NER), a specialized subpathway of nucleotide excision repair (NER). Exposure of mice to UVB light or chemicals has elucidated that TC-NER is a critical survival pathway protecting against acute toxic and long-term effects (cancer) of genotoxic exposure. Deficiency in TC-NER is associated with mutations in the CSA and CSB genes giving rise to the rare hu-man disorder Cockayne syndrome (CS). Recent data suggest that CSA and CSB play differential roles in mammalian TC-NER: CSB as a repair coupling factor to attract NER proteins, chromatin remodellers and the CSA- E3-ubiquitin iigase complex to the stalled RNAPI io. CSA is dispensable for attraction of NER proteins, yet in cooperation with CSB is required to recruit XAB2, the nucleosomal binding protein HMGNl and TFIIS. The emerging picture of TC-NER is complex: repair of transcription-blocking lesions occurs without displacement of the DNA damage-stalled RNAPIIo, and requires at least two essential assembly factors (CSA and CSB), the core NER factors (except for XPC-RAD23B), and TC-NER specific factors. These and yet unidentified proteins will accomplish not only efficient repair of transcrip-tion-blocking lesions, but are also likely to contribute to DNA damage signalling events.

  20. 5. MUTAGEN SENSITIVITY AND DNA REPAIR CAPACITY (DRC) AS RISK FACTORS FOR NON-SMALL CELL LUNG CANCER

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@An alkaline single cell gel electrophoresis assay has been standardised by which mutagen sensitivity and DNA repair capacity (DRC) can be measured in cryopreserved peripheral blood lymphocytes following induction and repair of DNA damage induced by bleomycin. In an ongoing case-control study, we have applied this assay to Caucasian

  1. Distinct kinetics of DNA repair protein accumulation at DNA lesions and cell cycle-dependent formation of gammaH2AX- and NBS1-positive repair foci

    Czech Academy of Sciences Publication Activity Database

    Suchánková, Jana; Kozubek, Stanislav; Legartová, Soňa; Sehnalová, Petra; Kuntzinger, T.; Bártová, Eva

    2015-01-01

    Roč. 107, č. 12 (2015), s. 440-454. ISSN 0248-4900 R&D Projects: GA ČR(CZ) GBP302/12/G157; GA ČR(CZ) GA13-07822S Institutional support: RVO:68081707 Keywords : Cell cycle * DNA repair * Interphase Subject RIV: BO - Biophysics Impact factor: 3.506, year: 2014

  2. Cetuximab affects the capacity of DNA repair in colorectal cancer cells after 125I seeds irradiation

    International Nuclear Information System (INIS)

    Objective: To investigate the effect of C225 on DNA repair and molecular pathways in CL187 colorectal cancer cells after irradiated by 125I radioactive seeds. Methods: In the experiment involved were four groups:control group, 100 nmol/L C225 treatment group,125I radioactive seeds continuous low-dose rate irradiation group and C225 combined with 125I radioactive seeds continuous low dose rate irradiation group. Cells were collected at 48 h after 4 Gy irradiation, and γH2AX foci/cell and γH2AX foci positive cells were counted with immunofluorescence. At the same time, DNA repair proteins were detected by Western blot. Cells were analyzed immediately after 4 Gy irradiation,and changes in EGFR downstream signaling molecules were detected by Western blot. Results: Compared with 125I seeds irradiated cells,cells treated with C225 and 125I seeds irradiation showed more γH2AX foci per cell (t=8.0, P=0.05), and more γH2AX foci positive cells (t=6.8, P<0.05) and less expression of Ku70 (t=6.6, P<0.05) and DNA-PKcs (t=5.6, P<0.05). Combined with 125I-CLDR irradiation, C225 reduced cellular EGFR level (t=4.9, P<0.05) and inhibited the activation of Akt (t=5.5, P<0.05). Conclusions: In the condition of 125I seeds irradiation, C225 reduced the expression of Ku70 and DNA-PKcs, inhibited the activation of Akt and attenuated the DNA damage repair capacity in CL187 colorectal cancer cells. (authors)

  3. Chromosomal Aberrations in DNA Repair Defective Cell Lines: Comparisons of Dose Rate and Radiation Quality

    Science.gov (United States)

    George, K. A.; Hada, M.; Patel, Z.; Huff, J.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Chromosome aberration yields were assessed in DNA double-strand break repair (DSB) deficient cells after acute doses of gamma-rays or high-LET iron nuclei, or low dose-rate (0.018 Gy/hr) gamma-rays. We studied several cell lines including fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase, DNA-PK activity. Chromosomes were analyzed using the fluorescence in-situ hybridization (FISH) chromosome painting method in cells at the first division post-irradiation and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma radiation induced higher yields of both simple and complex exchanges in the DSB repair defective cells than in the normal cells. The quadratic dose-response terms for both chromosome exchange types were significantly higher for the ATM and NBS defective lines than for normal fibroblasts. However, the linear dose-response term was significantly higher only for simple exchanges in the NBS cells. Large increases in the quadratic dose response terms indicate the important roles of ATM and NBS in chromatin modifications that facilitate correct DSB repair and minimize aberration formation. Differences in the response of AT and NBS deficient cells at lower doses suggests important questions about the applicability of observations of radiation sensitivity at high dose to low dose exposures. For all iron nuclei irradiated cells, regression models preferred purely linear and quadratic dose responses for simple and complex exchanges, respectively. All the DNA repair defective cell lines had lower Relative biological effectiveness (RBE) values than normal cells, the lowest being for the DNA-PK-deficient cells, which was near unity. To further

  4. A quantitative study of bone repair after endodontic therapy on digital subtraction radiography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Duk [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Chosun University, Kwangju (Korea, Republic of)

    1997-08-15

    This study was performed to prepare the quantitative method of judging the sensitive prognosis of chronic apical periodontitis as early as possible. The subjects were 25 cases with periapical radiolucencies of which were treated with endodontic treatment. Serial radiographs were taken by standardized method longitudinally. The density slice function of digital radiographic system were employed for quantitative and longitudinal assessment of the radiolucent area and the condensing osteitis simultaneously. Obtained results were as follows: 1. The amount of bone repair after endodontic treatment could be detected quantitatively by the density slice function of digital radiographic system. 2. Within the 6-week period after root canal filling, the prognosis could be evaluated by assessment both radiolucent area and condensing osteitis on digital radiographic system. 3. The pattern of bone repair showed peripheral type in most cases from the 6th week after root canal filling. 4. In longitudinal change, bone repair showed two patterns; the succeeding reduction of radiolucent area showing the increase of condensing osteitis in size till 6th week and following by static state or reduction tendency and the reduction following the initial increase of both areas. 5. Cases with pulpitis by trauma showed initial increase of condensing osteitis at 2nd week, marked reduction of radiolucent area and condensing osteitis at 6th week, and approximately normal bone state at 8th week after root canal filling.

  5. A quantitative study of bone repair after endodontic therapy on digital subtraction radiography

    International Nuclear Information System (INIS)

    This study was performed to prepare the quantitative method of judging the sensitive prognosis of chronic apical periodontitis as early as possible. The subjects were 25 cases with periapical radiolucencies of which were treated with endodontic treatment. Serial radiographs were taken by standardized method longitudinally. The density slice function of digital radiographic system were employed for quantitative and longitudinal assessment of the radiolucent area and the condensing osteitis simultaneously. Obtained results were as follows: 1. The amount of bone repair after endodontic treatment could be detected quantitatively by the density slice function of digital radiographic system. 2. Within the 6-week period after root canal filling, the prognosis could be evaluated by assessment both radiolucent area and condensing osteitis on digital radiographic system. 3. The pattern of bone repair showed peripheral type in most cases from the 6th week after root canal filling. 4. In longitudinal change, bone repair showed two patterns; the succeeding reduction of radiolucent area showing the increase of condensing osteitis in size till 6th week and following by static state or reduction tendency and the reduction following the initial increase of both areas. 5. Cases with pulpitis by trauma showed initial increase of condensing osteitis at 2nd week, marked reduction of radiolucent area and condensing osteitis at 6th week, and approximately normal bone state at 8th week after root canal filling.

  6. Regulation of DNA repair processes in mammalian cells. 3. Epidermal growth factor affects postirradiation recovery of cell cycle in human A431 and embryo fibroblast cells

    International Nuclear Information System (INIS)

    Recovery of the cell cycle in cells A 431 and in human embryo fibroblasts (EFH) differs much. Unlike EFH, A 431 cells have: 1) synchronized exit of cells from G1 into S phase after 5 Gr irradiation; 2) G2-block; 3) much less manifestation of these two phenomena in the presence of EGF; 4) a lesser effectiveness of the repair of DNA single-strand breaks. EGF stimulation of the repair of radiation-induced DNA lesions, SSB in particular, may be of great importance for the postirradiation cell cycle recovery

  7. Differential role of Rad51 in repair of DNA damage induced by β-rays of 131I in Raji cells: a comparison with the γ-rays

    International Nuclear Information System (INIS)

    Radioiodine is one of the oldest radionuclide used in therapy of thyroid disorder. The scope of application of radioiodine increased tremendously due to simple method of labeling of biomolecules with 131I without significant changes in biological properties. Thus, biomolecules labeled with 131I promised immense potential as therapeutic radiopharmaceuticals for cancer. The therapeutic efficacy depends on the characteristics of the β-emitter attached. The mechanisms of cell death and DNA damage repair induced by β-emitting radionuclide are not well known. In this experiment, the authors have attempted to investigate the underlying mechanism causing cell death in Raji cells and have compared the therapeutic efficacy of beta emitter, 131I, to γ-radiation by exposing the cells to an equivalent dose of γ-. Raji cells were incubated for 2h with 1.85 MBq of 131I radioactivity. Equal numbers of cells were exposed to an equivalent dose (0.4 Gy) and a therapeutic dose of 2 Gy from gamma radiation. Cell toxicity was assessed by trypan blue dye and MTT assay. Apoptosis was assessed by estimation of DNA fragmentation and cleaved PARP proteins. Radiosensitivity and DNA damage repair gene expression were analyzed by real time q-PCR. Cell viability and proliferation study confirms that Raji cell line showed comparatively higher radiosensitivity with beta emitter (131I) compared to γ-rays. In the case of apoptosis, beta emitter (131I) showed significantly high DNA fragmentation and PARP cleavage. RAD51 gene expression does not change with time in the case of 131I while it changes in the case of γ-radiation. Beta radiation from 131I is observed to be more potent in induction of cell toxicity and apoptosis in Raji cells than the γ-rays. However, RAD51 does not take part in the DNA DSB repair pathway induced by 131I and therefore play a major role in discriminating the effect of gamma rays. (author)

  8. Kallikrein-kinin in stem cell therapy

    Institute of Scientific and Technical Information of China (English)

    Julie; Chao; Grant; Bledsoe; Lee; Chao

    2014-01-01

    The tissue kallikrein-kinin system exerts a wide spectrum of biological activities in the cardiovascular, renal and central nervous systems. Tissue kallikrein-kinin modulates the proliferation, viability, mobility and functional activity of certain stem cell populations, namely mesenchymal stem cells(MSCs), endothelial progenitor cells(EPCs), mononuclear cell subsets and neural stem cells. Stimulation of these stem cells by tissue kallikrein-kinin may lead to protection against renal, cardiovascular and neural damage by inhibiting apoptosis, inflammation, fibrosis and oxidative stress and promoting neovascularization. Moreover, MSCs and EPCs genetically modified with tissue kallikrein are resistant to hypoxia- and oxidative stress-induced apoptosis, and offer enhanced protective actions in animal models of heart and kidney injury and hindlimb ischemia. In addition, activation of the plasma kallikrein-kinin system promotes EPC recruitment to the inflamed synovium of arthritic rats. Conversely, cleaved high molecular weight kininogen, a product of plasma kallikrein, reduces the viability and vasculogenic activity of EPCs. Therefore, kallikrein-kinin provides a new approach in enhancing the efficacy of stem cell therapy for human diseases.

  9. Therapeutic potential of stem cells in skin repair and regeneration

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cui-ping; FU Xiao-bing

    2008-01-01

    @@ Stem cells are defined by their capacity of self-renewal and multilineage differentiation, which make them uniquely situated to treat a broad spectrum of human diseases. Based on a series of remarkable studies in several fields of regen-erative medicine, their application is not too far from the clinical practice.

  10. More efficient repair of DNA double-strand breaks in skeletal muscle stem cells compared to their committed progeny

    Directory of Open Access Journals (Sweden)

    Leyla Vahidi Ferdousi

    2014-11-01

    Full Text Available The loss of genome integrity in adult stem cells results in accelerated tissue aging and is possibly cancerogenic. Adult stem cells in different tissues appear to react robustly to DNA damage. We report that adult skeletal stem (satellite cells do not primarily respond to radiation-induced DNA double-strand breaks (DSBs via differentiation and exhibit less apoptosis compared to other myogenic cells. Satellite cells repair these DNA lesions more efficiently than their committed progeny. Importantly, non-proliferating satellite cells and post-mitotic nuclei in the fiber exhibit dramatically distinct repair efficiencies. Altogether, reduction of the repair capacity appears to be more a function of differentiation than of the proliferation status of the muscle cell. Notably, satellite cells retain a high efficiency of DSB repair also when isolated from the natural niche. Finally, we show that repair of DSB substrates is not only very efficient but, surprisingly, also very accurate in satellite cells and that accurate repair depends on the key non-homologous end-joining factor DNA-PKcs.

  11. Relationship of DNA repair processes to mutagenesis and carcinogenesis in mammalian cells. Progress report, August 1, 1977-October 31, 1980

    International Nuclear Information System (INIS)

    The objective of this research is to determine the role of DNA repair in mutagenesis and carcinogenesis in mammalian cells. More specifically, mutant strains will be selected which are deficient in various DNA repair pathways. These strains will be studied with regard to (1) the nature of the defect in repair, and (2) the mutability and transformability of the defective cells by various agents as compared to the wild type parental cells. The results to date include progress in the following areas: (1) determination of optimum conditions for growth and maintenance of cells and for quantitative measurement of various cellular parameters; (2) investigation of the effect of holding mutagenized cells for various periods in a density inhibited state on survival and on mutation and transformation frequencies; (3) examination of the repair capabilities of BHK cells, as compared to repair-proficient and repair-deficient human cells and excision-deficient mouse cells, as measured by the reactivation of Herpes simplex virus (HSV) treated with radiation and ethylmethane sulfonate (EMS); (4) initiation of host cell reactivation viral sucide enrichment and screening of survivors of the enrichment for sensitivity to ionizing radiation; and (5) investigation of the toxicity, mutagenicity, and carcinogenicity of various metabolites of 4-nitroquinoline-1-oxide (4-NQO)

  12. DNA repair in HeLa Zh-63 cells after irradiation and action of chemical carcinogens

    International Nuclear Information System (INIS)

    In HeLa Zh-63 cells prelabelled with 3H-thymidine the repair of γ-ray-induced single-strand breaks in the nutrient medium and in the buffer proceeds with the same intensity. The process is inhibited with acriflavine, quinacrine and 2,4-dinitrophenol but not with caffeine. The repair of double-strand breaks of DNA in the nutrient medium is more complete than in the buffer. It is inhibited by acriflavine but not by caffeine. In cells pulse-labelled with 3H-thymidine after U.V.-irradiation and 7-bromomethylbenz-(α)anthracene (BMBA) treatment the nascent DNA has a low molecular weight (Msub(w)). In U.V.-irradiated cells during incubation Msub(w) restores to the control level. In BMBA-treated cells Msub(w) is not restored within the first 6 h, but 18-21 h later DNA of a normal Msub(w) is synthesized. After the action of γ-rays and 2-aminofluorene (AF) nascent DNA with a normal Msub(w) is synthesized. When a pulse label is introduced simultaneously with caffeine after γ-ray-irradiation and BMBA (but not U.V.-light or AF) treatment the Msub(w) of nascent DNA is less than in the case without caffeine. It is assumed to be due to fast post-replication repair (during pulse labelling) which is sensitive to caffeine. (author)

  13. Chronic Liver Disease: Stem Cell Therapy

    Directory of Open Access Journals (Sweden)

    Gamal MA Hassan

    2013-03-01

    Full Text Available Chronic liver diseases (CLD affect hundreds of millions of patientsworldwide. Stem Cells (SCs therapy to treat chronic liver diseasesis resorted and is considered as the dream of the future. AlthoughSCs are a promising means for treatment of liver diseases, studiesare still at the beginning of this era. SCs are undifferentiatedcells capable of renewing themselves throughout their life and ofgenerating one or more types of differentiated cells. Different typesof SCs with hepatic differentiation potential are theoretically eligiblefor liver cell replacement. These include Embryonic and fetal liverSCs, induced pluripotent SCs, hepatoblasts, annex SCs (pluripotentSCs obtained from umbilical cord and umbilical cord blood,placenta and amniotic fluid, and adult SCs, such hepatic progenitorcells, hematopoietic SCs, and mesenchymal stem cell. The optimalSCs delivery route should be easy to perform, less invasive andtraumatic, minimum side effects, and with high cells survival rate.Liver SCs can be transplanted through several routes: Intraperitonealand percutaneous intrahepatic artery catheterization in acute liverfailure, and umbilical vein catheterization, percutaneous intrahepaticroute, and portal vein or intrahepatic artery catheterization inmetabolic liver diseases. Whatever the source or delivery route ofSCs, how they can be manipulated for therapeutic interventionsin a variety of hepatic diseases is of course of great interest infuture studies. Although all clinical trials to date have shown someimprovement in liver function and CD34+ cells have been usedsafely for bone marrow transplantation for over 20 years, onlyrandomized controlled clinical trials will be able to fully assess thepotential clinical benefit of adult SCs therapy for patients with CLD.

  14. Optimizing autologous cell grafts to improve stem cell gene therapy.

    Science.gov (United States)

    Psatha, Nikoletta; Karponi, Garyfalia; Yannaki, Evangelia

    2016-07-01

    Over the past decade, stem cell gene therapy has achieved unprecedented curative outcomes for several genetic disorders. Despite the unequivocal success, clinical gene therapy still faces challenges. Genetically engineered hematopoietic stem cells are particularly vulnerable to attenuation of their repopulating capacity once exposed to culture conditions, ultimately leading to low engraftment levels posttransplant. This becomes of particular importance when transduction rates are low or/and competitive transplant conditions are generated by reduced-intensity conditioning in the absence of a selective advantage of the transduced over the unmodified cells. These limitations could partially be overcome by introducing megadoses of genetically modified CD34(+) cells into conditioned patients or by transplanting hematopoietic stem cells hematopoietic stem cells with high engrafting and repopulating potential. On the basis of the lessons gained from cord blood transplantation, we summarize the most promising approaches to date of increasing either the numbers of hematopoietic stem cells for transplantation or/and their engraftability, as a platform toward the optimization of engineered stem cell grafts. PMID:27106799

  15. Low-dose formaldehyde delays DNA damage recognition and DNA excision repair in human cells.

    Directory of Open Access Journals (Sweden)

    Andreas Luch

    Full Text Available OBJECTIVE: Formaldehyde is still widely employed as a universal crosslinking agent, preservative and disinfectant, despite its proven carcinogenicity in occupationally exposed workers. Therefore, it is of paramount importance to understand the possible impact of low-dose formaldehyde exposures in the general population. Due to the concomitant occurrence of multiple indoor and outdoor toxicants, we tested how formaldehyde, at micromolar concentrations, interferes with general DNA damage recognition and excision processes that remove some of the most frequently inflicted DNA lesions. METHODOLOGY/PRINCIPAL FINDINGS: The overall mobility of the DNA damage sensors UV-DDB (ultraviolet-damaged DNA-binding and XPC (xeroderma pigmentosum group C was analyzed by assessing real-time protein dynamics in the nucleus of cultured human cells exposed to non-cytotoxic (<100 μM formaldehyde concentrations. The DNA lesion-specific recruitment of these damage sensors was tested by monitoring their accumulation at local irradiation spots. DNA repair activity was determined in host-cell reactivation assays and, more directly, by measuring the excision of DNA lesions from chromosomes. Taken together, these assays demonstrated that formaldehyde obstructs the rapid nuclear trafficking of DNA damage sensors and, consequently, slows down their relocation to DNA damage sites thus delaying the excision repair of target lesions. A concentration-dependent effect relationship established a threshold concentration of as low as 25 micromolar for the inhibition of DNA excision repair. CONCLUSIONS/SIGNIFICANCE: A main implication of the retarded repair activity is that low-dose formaldehyde may exert an adjuvant role in carcinogenesis by impeding the excision of multiple mutagenic base lesions. In view of this generally disruptive effect on DNA repair, we propose that formaldehyde exposures in the general population should be further decreased to help reducing cancer risks.

  16. Stem Cell-Based Cell Therapy for Glomerulonephritis

    Directory of Open Access Journals (Sweden)

    Meiling Jin

    2014-01-01

    Full Text Available Glomerulonephritis (GN, characterized by immune-mediated inflammatory changes in the glomerular, is a common cause of end stage renal disease. Therapeutic options for glomerulonephritis applicable to all cases mainly include symptomatic treatment and strategies to delay progression. In the attempt to yield innovative interventions fostering the limited capability of regeneration of renal tissue after injury and the uncontrolled pathological process by current treatments, stem cell-based therapy has emerged as novel therapy for its ability to inhibit inflammation and promote regeneration. Many basic and clinical studies have been performed that support the ability of various stem cell populations to ameliorate glomerular injury and improve renal function. However, there is a long way before putting stem cell-based therapy into clinical practice. In the present article, we aim to review works performed with respect to the use of stem cell of different origins in GN, and to discuss the potential mechanism of therapeutic effect and the challenges for clinical application of stem cells.

  17. Treatment of acute lung injury by targeting MG53-mediated cell membrane repair

    OpenAIRE

    Jia, Yanlin; Chen, Ken; Lin, Peihui; Lieber, Gissela; Nishi, Miyuki; Yan, Rosalie; Wang, Zhen; Yao, Yonggang; LI Yu; Bryan A Whitson; Duann, Pu; Li, Haichang; Zhou, Xinyu; Zhu, Hua; Takeshima, Hiroshi

    2014-01-01

    Injury to lung epithelial cells has a role in multiple lung diseases. We previously identified mitsugumin 53 (MG53) as a component of the cell membrane repair machinery in striated muscle cells. Here we show that MG53 also has a physiological role in the lung and may be used as a treatment in animal models of acute lung injury. Mice lacking MG53 show increased susceptibility to ischemia-reperfusion and over-ventilation induced injury to the lung when compared with wild type mice. Extracellula...

  18. DNA strand breaks induced by 125I in cultured human kidney cells and their repair

    International Nuclear Information System (INIS)

    125I was incorporated into the DNA of cultured human kidney cells. In intact cells, 4 single-strand breaks per decay were measured. Two SSBs per decay were found in isolated DNA. The numbers of double-strand breaks per decay in two experiments ranged from 1.4 to 2.7 depending on two different constants used in the calculations. A detailed microdosimetric analysis will be necessary to establish relationships between eV absorbed in DNA after 125I-decay and numbers of induced strand breaks. By incubation of the cells after exposure repair of SSBs could be demonstrated. This was not the case for DSBs

  19. Reduced repair of 8-hydroxyguanine in the human breast cancer cell line, HCC1937

    International Nuclear Information System (INIS)

    Breast cancer is the second leading cause of cancer deaths in women in the United States. Although the causes of this disease are incompletely understood, oxidative DNA damage is presumed to play a critical role in breast carcinogenesis. A common oxidatively induced DNA lesion is 8-hydroxyguanine (8-OH-Gua), which has been implicated in carcinogenesis. The aim of this study was to investigate the ability of HCC1937 and MCF-7 breast cancer cell lines to repair 8-OH-Gua relative to a nonmalignant human mammary epithelial cell line, AG11134. We used oligonucleotide incision assay to analyze the ability of the two breast cancer cell lines to incise 8-OH-Gua relative to the control cell line. Liquid chromatography/mass spectrometry (LC/MS) was used to measure the levels of 8-OH-Gua as its nucleoside, 8-OH-dG in the cell lines after exposure to H2O2 followed by 30 min repair period. Protein expression levels were determined by Western blot analysis, while the hOGG1 mRNA levels were analyzed by RT-PCR. Complementation of hOGG1 activity in HCC1937 cells was assessed by addition of the purified protein in the incision assay, and in vivo by transfection of pFlagCMV-4-hOGG1. Clonogenic survival assay was used to determine sensitivity after H2O2-mediated oxidative stress. We show that the HCC1937 breast cancer cells have diminished ability to incise 8-OH-Gua and they accumulate higher levels of 8-OH-dG in the nuclear genome after H2O2 treatment despite a 30 min repair period when compared to the nonmalignant mammary cells. The defective incision of 8-OH-Gua was consistent with expression of undetectable amounts of hOGG1 in HCC1937 cells. The reduced incision activity was significantly stimulated by addition of purified hOGG1. Furthermore, transfection of pFlagCMV-4-hOGG1 in HCC1937 cells resulted in enhanced incision of 8-OH-Gua. HCC1937 cells are more sensitive to high levels of H2O2 and have up-regulated SOD1 and SOD2. This study provides evidence for inefficient repair of 8

  20. Advances in combining gene therapy with cell and tissue engineering-based approaches to enhance healing of the meniscus.

    Science.gov (United States)

    Cucchiarini, M; McNulty, A L; Mauck, R L; Setton, L A; Guilak, F; Madry, H

    2016-08-01

    Meniscal lesions are common problems in orthopaedic surgery and sports medicine, and injury or loss of the meniscus accelerates the onset of knee osteoarthritis (OA). Despite a variety of therapeutic options in the clinics, there is a critical need for improved treatments to enhance meniscal repair. In this regard, combining gene-, cell-, and tissue engineering-based approaches is an attractive strategy to generate novel, effective therapies to treat meniscal lesions. In the present work, we provide an overview of the tools currently available to improve meniscal repair and discuss the progress and remaining challenges for potential future translation in patients. PMID:27063441

  1. Defective repair of uracil causes telomere defects in mouse hematopoietic cells.

    Science.gov (United States)

    Vallabhaneni, Haritha; Zhou, Fang; Maul, Robert W; Sarkar, Jaya; Yin, Jinhu; Lei, Ming; Harrington, Lea; Gearhart, Patricia J; Liu, Yie

    2015-02-27

    Uracil in the genome can result from misincorporation of dUTP instead of dTTP during DNA synthesis, and is primarily removed by uracil DNA glycosylase (UNG) during base excision repair. Telomeres contain long arrays of TTAGGG repeats and may be susceptible to uracil misincorporation. Using model telomeric DNA substrates, we showed that the position and number of uracil substitutions of thymine in telomeric DNA decreased recognition by the telomere single-strand binding protein, POT1. In primary mouse hematopoietic cells, uracil was detectable at telomeres, and UNG deficiency further increased uracil loads and led to abnormal telomere lengthening. In UNG-deficient cells, the frequencies of sister chromatid exchange and fragility in telomeres also significantly increased in the absence of telomerase. Thus, accumulation of uracil and/or UNG deficiency interferes with telomere maintenance, thereby underscoring the necessity of UNG-initiated base excision repair for the preservation of telomere integrity. PMID:25572391

  2. Papovavirus probes for DNA repair in human cells: Final report, August 15, 1983-May 15, 1987

    International Nuclear Information System (INIS)

    Extracellularly gamma irradiated simian virus 40 (SV40) was used as a model system to study the induction and intracellular repair of DSB (double-strand DNA breaks) and SSB (single-strand DNA breaks) in higher cells. The optimal experimental conditions for this approach were determined and the comparability of radiation dose-response data were compared with those obtained by other techniques. Experiments in progress suggest that limited accessibility of heavily irradiated viral DNA to host cell enzymes leads to variable rates of repair of DSB or SSB. The effects of DNA configuration and molecular environment on the radiation induction of DSB, using SV40 as a model system are addressed. Results indicate that the intranuclear environment is highly protective against DSB induced by ionizing radiation. 9 refs., 11 figs., 3 tabs

  3. Induction of repair functions by hydrogen peroxide in Chinese hamster cells

    International Nuclear Information System (INIS)

    Hydrogen peroxide has been found to kill Chinese hamster V79 cells as an exponential function of dose. When a small dose (0.9 μg/ml for 1 h) was used as a pretreatment, before exposure to higher concentrations of the same agent, the cells became more resistant to killing than those which were not so pretreated. The presence of cycloheximide or benzamide, during this pretreatment, inhibited this observed increase in resistance. This pretreatment also resulted in decreased killing efficiency by MNNG and gamma-rays, but had no effect upon UV-light-induced killing. The results suggest that proteins (repair enzymes?) are synthesized after treatment with the small dose of hydrogen peroxide, and that these induced proteins enhance the cellular repair functions for agents causing DNA breaks. (author)

  4. STAT3 signaling controls satellite cell expansion and skeletal muscle repair

    Science.gov (United States)

    Tierney, Matthew Timothy; Aydogdu, Tufan; Sala, David; Malecova, Barbora; Gatto, Sole; Puri, Pier Lorenzo; Latella, Lucia; Sacco, Alessandra

    2015-01-01

    The progression of disease- and age-dependent skeletal muscle wasting results in part from a decline in the number and function of satellite cells, the direct cellular contributors to muscle repair1–10. However, little is known about the molecular effectors underlying satellite cell impairment and depletion. Elevated levels of inflammatory cytokines, including interleukin-6 (IL-6), are associated with both age-related and muscle-wasting conditions11–13. The levels of STAT3, a downstream effector of IL-6, are also elevated with muscle wasting14,15, and STAT3 has been implicated in the regulation of self-renewal and stem cell fate in several tissues16–19. Here we show that IL-6–activated Stat3 signaling regulates satellite cell behavior, promoting myogenic lineage progression through myogenic differentiation 1 (Myod1) regulation. Conditional ablation of Stat3 in Pax7-expressing satellite cells resulted in their increased expansion during regeneration, but compromised myogenic differentiation prevented the contribution of these cells to regenerating myofibers. In contrast, transient Stat3 inhibition promoted satellite cell expansion and enhanced tissue repair in both aged and dystrophic muscle. The effects of STAT3 inhibition were conserved in human myoblasts. The results of this study indicate that pharmacological manipulation of STAT3 activity can be used to counteract the functional exhaustion of satellite cells, thereby maintaining the endogenous regenerative response and ameliorating muscle-wasting diseases. PMID:25194572

  5. Brain-peripheral cell crosstalk in white matter damage and repair.

    Science.gov (United States)

    Hayakawa, Kazuhide; Lo, Eng H

    2016-05-01

    White matter damage is an important part of cerebrovascular disease and may be a significant contributing factor in vascular mechanisms of cognitive dysfunction and dementia. It is well accepted that white matter homeostasis involves multifactorial interactions between all cells in the axon-glia-vascular unit. But more recently, it has been proposed that beyond cell-cell signaling within the brain per se, dynamic crosstalk between brain and systemic responses such as circulating immune cells and stem/progenitor cells may also be important. In this review, we explore the hypothesis that peripheral cells contribute to damage and repair after white matter damage. Depending on timing, phenotype and context, monocyte/macrophage can possess both detrimental and beneficial effects on oligodendrogenesis and white matter remodeling. Endothelial progenitor cells (EPCs) can be activated after CNS injury and the response may also influence white matter repair process. These emerging findings support the hypothesis that peripheral-derived cells can be both detrimental or beneficial in white matter pathology in cerebrovascular disease. This article is part of a Special Issue entitled: Vascular Contributions to Cognitive Impairment and Dementia, edited by M. Paul Murphy, Roderick A. Corriveau and Donna M. Wilcock. PMID:26277436

  6. Induction and repair of DNA strand breaks in bovine lens epithelial cells after high LET irradiation

    Science.gov (United States)

    Baumstark-Khan, C.; Heilmann, J.; Rink, H.

    The lens epithelium is the initiation site for the development of radiation induced cataracts. Radiation in the cortex and nucleus interacts with proteins, while in the epithelium, experimental results reveal mutagenic and cytotoxic effects. It is suggested that incorrectly repaired DNA damage may be lethal in terms of cellular reproduction and also may initiate the development of mutations or transformations in surviving cells. The occurrence of such genetically modified cells may lead to lens opacification. For a quantitative risk estimation for astronauts and space travelers it is necessary to know the relative biological effectiveness (RBE), because the spacial and temporal distribution of initial physical damage induced by cosmic radiation differ significantly from that of X-rays. RBEs for the induction of DNA strand breaks and the efficiency of repair of these breaks were measured in cultured diploid bovine lens epithelial cells exposed to different LET irradiation to either 300 kV X-rays or to heavy ions at the UNILAC accelerator at GSI. Accelerated ions from Z=8 (O) to Z=92 (U) were used. Strand breaks were measured by hydroxyapatite chromatography of alkaline unwound DNA (overall strand breaks). Results showed that DNA damage occurs as a function of dose, of kinetic energy and of LET. For particles having the same LET the severity of the DNA damage increases with dose. For a given particle dose, as the LET rises, the numbers of DNA strand breaks increase to a maximum and then reach a plateau or decrease. Repair kinetics depend on the fluence (irradiation dose). At any LET value, repair is much slower after heavy ion exposure than after X-irradiation. For ions with an LET of less than 10,000 keV μ -1 more than 90 percent of the strand breaks induced are repaired within 24 hours. At higher particle fluences, especially for low energetic particles with a very high local density of energy deposition within the particle track, a higher proportion of non

  7. Cell-Based Therapy for Silicosis.

    Science.gov (United States)

    Lopes-Pacheco, Miquéias; Bandeira, Elga; Morales, Marcelo M

    2016-01-01

    Silicosis is the most common pneumoconiosis globally, with higher prevalence and incidence in developing countries. To date, there is no effective treatment to halt or reverse the disease progression caused by silica-induced lung injury. Significant advances have to be made in order to reduce morbidity and mortality related to silicosis. In this review, we have highlighted the main mechanisms of action that cause lung damage by silica particles and summarized the data concerning the therapeutic promise of cell-based therapy for silicosis. PMID:27066079

  8. Cell-Based Therapy for Silicosis

    Directory of Open Access Journals (Sweden)

    Miquéias Lopes-Pacheco

    2016-01-01

    Full Text Available Silicosis is the most common pneumoconiosis globally, with higher prevalence and incidence in developing countries. To date, there is no effective treatment to halt or reverse the disease progression caused by silica-induced lung injury. Significant advances have to be made in order to reduce morbidity and mortality related to silicosis. In this review, we have highlighted the main mechanisms of action that cause lung damage by silica particles and summarized the data concerning the therapeutic promise of cell-based therapy for silicosis.

  9. Survival and DNA repair in ultraviolet-irradiated haploid and diploid cultured frog cells

    International Nuclear Information System (INIS)

    Survival and repair of DNA following ultraviolet (254-nm) radiation have been investigated in ICR 2A, a cultured cell line from haploid embryos of the grassfrog, Rana pipiens. Survival curves from cells recovering in the dark gave mean lethal dose value (D0) in the range 1.5-1.7 Jm-2 for both haploid and diploid cell stocks. The only significant difference observed between haploids and diploids was in the extent of the shoulder at low fluence (Dsub(q)), the value for exponentially multiplying diploid cells (3.0 Jm-2) being higher than that found for haploids (1.2 Jm-2). Irradiation of cultures reversibly blocked in the G1 phase of the cell cycle gave survival-curve coefficients indistinguishable between haploids and diploids. Post-irradiation exposure to visible light restored colony-forming capacity and removed chromatographically estimated pyrimidine dimers from DNA at the same rates. After fluences killing 90% of the cells, complete restoration of survival was obtained after 60-min exposure to 500 foot-candles, indicating that in this range lethality is entirely photoreversible and therefore attributable to pyrimidine dimers in DNA. Dimer removal required illumination following ultraviolet exposure, intact cells and physiological temperature, implying that the photoreversal involved DNA photolyase activity. Excision-repair capacity was slight, since no loss of dimers could be detected chromoatographically during up to 48 h incubation in the dark and since autoradiographically detected 'unscheduled DNA synthesis' was limited to a 2-fold increase saturated at 10 Jm-2. These properties make ICR 2A frog cells useful to explore how DNA-repair pathways influence mutant yield. (Auth.)

  10. Transient elevation of glycolysis confers radio-resistance by facilitating DNA repair in cells

    International Nuclear Information System (INIS)

    Cancer cells exhibit increased glycolysis for ATP production (the Warburg effect) and macromolecular biosynthesis; it is also linked with therapeutic resistance that is generally associated with compromised respiratory metabolism. Molecular mechanisms underlying radio-resistance linked to elevated glycolysis remain incompletely understood. We stimulated glycolysis using mitochondrial respiratory modifiers (MRMs viz. di-nitro phenol, DNP; Photosan-3, PS3; Methylene blue, MB) in established human cell lines (HEK293, BMG-1 and OCT-1). Glucose utilization and lactate production, levels of glucose transporters and glycolytic enzymes were investigated as indices of glycolysis. Clonogenic survival, DNA repair and cytogenetic damage were studied as parameters of radiation response. MRMs induced the glycolysis by enhancing the levels of two important regulators of glucose metabolism GLUT-1 and HK-II and resulted in 2 fold increase in glucose consumption and lactate production. This increase in glycolysis resulted in resistance against radiation-induced cell death (clonogenic survival) in different cell lines at an absorbed dose of 5 Gy. Inhibition of glucose uptake and glycolysis (using fasentin, 2-deoxy-D-glucose and 3-bromopyruvate) in DNP treated cells failed to increase the clonogenic survival of irradiated cells, suggesting that radio-resistance linked to inhibition of mitochondrial respiration is glycolysis dependent. Elevated glycolysis also facilitated rejoining of radiation-induced DNA strand breaks by activating both non-homologous end joining (NHEJ) and homologous recombination (HR) pathways of DNA double strand break repair leading to a reduction in radiation-induced cytogenetic damage (micronuclei formation) in these cells. These findings suggest that enhanced glycolysis generally observed in cancer cells may be responsible for the radio-resistance, partly by enhancing the repair of DNA damage

  11. Defective DNA repair and increased genomic instability in Cernunnos-XLF-deficient murine ES cells.

    Science.gov (United States)

    Zha, Shan; Alt, Frederick W; Cheng, Hwei-Ling; Brush, James W; Li, Gang

    2007-03-13

    Nonhomologous DNA end-joining (NHEJ) is a major pathway of DNA double-strand break (DSB) repair in mammalian cells, and it functions to join both specifically programmed DSBs that occur in the context of V(D)J recombination during early lymphocyte development as well as general DSBs that occur in all cells. Thus, defects in NHEJ impair V(D)J recombination and lead to general genomic instability. In human patients, mutations of Cernunnos-XLF (also called NHEJ1), a recently identified NHEJ factor, underlie certain severe combined immune deficiencies associated with defective V(D)J recombination and radiosensitivity. To characterize Cernunnos-XLF function in mouse cells, we used gene-targeted mutation to delete exons 4 and 5 from both copies of the Cernunnos-XLF gene in ES cell (referred to as Cer(Delta/Delta) ES cells). Analyses of Cer(Delta/Delta) ES cells showed that they produce no readily detectable Cernunnos-XLF protein. Based on transient V(D)J recombination assays, we find that Cer(Delta/Delta) ES cells have dramatic impairments in ability to form both V(D)J coding joins and joins of their flanking recombination signal sequences (RS joins). Cer(Delta/Delta) ES cells are highly sensitive to ionizing radiation and have intrinsic DNA DSB repair defects as measured by pulse field gel electrophoresis. Finally, the Cernunnos-XLF mutations led to increased spontaneous genomic instability, including translocations. We conclude that, in mice, Cernunnos-XLF is essential for normal NHEJ-mediated repair of DNA DSBs and that Cernunnos-XLF acts as a genomic caretaker to prevent genomic instability. PMID:17360556

  12. Break-induced replication repair of damaged forks induces genomic duplications in human cells

    OpenAIRE

    Costantino, L.; Sotiriou, S. K.; Rantala, J. K.; Magin, S.; Mladenov, E.; Helleday, T.; Haber, J E; Iliakis, G.; Kallioniemi, O P; Halazonetis, T D

    2013-01-01

    In budding yeast, one-ended DNA double-strand breaks (DSBs) and damaged replication forks are repaired by break-induced replication (BIR), a homologous recombination pathway that requires the Pol32 subunit of DNA polymerase delta. DNA replication stress is prevalent in cancer, but BIR has not been characterized in mammals. In a cyclin E overexpression model of DNA replication stress, POLD3, the human ortholog of POL32, was required for cell cycle progression and processive DNA synthesis. Segm...

  13. Transplanted Bone Marrow Cells Repair Heart Tissue and Reduce Myocarditis in Chronic Chagasic Mice

    OpenAIRE

    MILENA B. P. SOARES; Lima, Ricardo S.; Rocha, Leonardo L.; Takyia, Christina M; Pontes-de-Carvalho, Lain; Campos de Carvalho, Antonio C.; Ribeiro-dos-Santos, Ricardo

    2004-01-01

    A progressive destruction of the myocardium occurs in ∼30% of Trypanosoma cruzi-infected individuals, causing chronic chagasic cardiomyopathy, a disease so far without effective treatment. Syngeneic bone marrow cell transplantation has been shown to cause repair and improvement of heart function in a number of studies in patients and animal models of ischemic cardiopathy. The effects of bone marrow transplant in a mouse model of chronic chagasic cardiomyopathy, in the presence of the disease ...

  14. rBMP Represses Wnt Signaling and Influences Skeletal Progenitor Cell Fate Specification During Bone Repair

    OpenAIRE

    Minear, Steve; Leucht, Philipp; Miller, Samara; Helms, Jill A.

    2010-01-01

    Bone morphogenetic proteins (BMPs) participate in multiple stages of the fetal skeletogenic program from promoting cell condensation to regulating chondrogenesis and bone formation through endochondral ossification. Here, we show that these pleiotropic functions are recapitulated when recombinant BMPs are used to augment skeletal tissue repair. In addition to their well-documented ability to stimulate chondrogenesis in a skeletal injury, we show that recombinant BMPs (rBMPs) simultaneously su...

  15. Can Estuary Sediment Contaminants Interfere with the DNA Repair Capacity of HEPG2 Cells?

    OpenAIRE

    Pinto, Miguel; Louro, Henriqueta; Costa, Pedro Manuel; Caeiro, Sandra; Silva, Maria João

    2013-01-01

    Estuarine sediments tend to act as reservoirs of pollutants, many of which are acknowledged genotoxicants and potential carcinogens for humans. In addition, many of these environmental contaminants, particularly metals, have the potential to interfere with DNA repair mechanisms. Taking an impacted estuary as a case study (the Sado, SW Portugal), previous studies showed that human hepatoma cells (HepG2) exposed to extracts of sediments collected from two areas (urban/industrial and riverine/ag...

  16. Peripheral blood mononuclear cells enhance cartilage repair in in vivo osteochondral defect model

    OpenAIRE

    Hopper, Niina; Wardale, John; Brooks, Roger; Power, Roger; Power, Jonathan, 1941-; Rushtown, Neil; Henson, Frances

    2015-01-01

    This study characterized peripheral blood mononuclear cells (PBMC) in terms of their potential in cartilage repair and investigated their ability to improve the healing in a pre-clinical large animal model. Human PBMCs were isolated with gradient centrifugation and adherent PBMC’s were evaluated for their ability to differentiate into adipogenic, chondrogenic and osteogenic lineages and also for their expression of musculoskeletal genes. The phenotype of the PBMCs was evaluated using Stro-1, ...

  17. Mutagenic specificity of solar UV light in nucleotide excision repair-deficient rodent cells.

    OpenAIRE

    Sage, E.; Lamolet, B; Brulay, E; Moustacchi, E; Chteauneuf, A; Drobetsky, E A

    1996-01-01

    To investigate the role of nucleotide excision repair (NER) in the cellular processing of carcinogenic DNA photoproducts induced by defined, environmentally relevant portions of the solar wavelength spectrum, we have determined the mutagenic specificity of simulated sunlight (310-1100 nm), UVA (350-400 nm), and UVB (290-320 nm), as well as of the "nonsolar" model mutagen 254-nm UVC, at the adenine phosphoribosyltransferase (aprt) locus in NER-deficient (ERCC1) Chinese hamster ovary (CHO) cell...

  18. Present and future cell therapies for pancreatic beta cell replenishment

    Institute of Scientific and Technical Information of China (English)

    Juan Domínguez-Bendala; Camillo Ricordi

    2012-01-01

    If only at a small scale,islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy:the functional replenishment of damaged tissue in patients.After years of less-thanoptimal approaches to immunosuppression,recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation.Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this pioneering intervention.Progress in stem cell research over the past decade,coupled with our decades-long experience with islet transplantation,is shaping the future of cell therapies for the treatment of diabetes.Here we review the most promising avenues of research aimed at generating an inexhaustible supply of insulin-producing cells for islet regeneration,including the differentiation of pluripotent and multipotent stem cells of embryonic and adult origin along the beta cell lineage and the direct reprogramming of non-endocrine tissues into insulin-producing cells.

  19. The role of immunosuppression of mesenchymal stem cells in tissue repair and tumor growth

    Directory of Open Access Journals (Sweden)

    Han Zhipeng

    2012-03-01

    Full Text Available Abstract Mesenchymal stem cells (MSCs have acquired great interests for their potential use in the clinical therapy of many diseases because of their functions including multiple lineage differentiation, low immunogenicity and immunosuppression. Many studies suggest that MSCs are strongly immunosuppressive in vitro and in vivo. MSCs exert a profound inhibitory effect on the proliferation of T cells, B cells, dendritic cells and natural killer cells. In addition, several soluble factors have been reported to involved in the immunosuppressive effects by MSCs such as TGF-β, HGF, PGE2, IDO and iNOS. These results suggest that MSCs can be used in the therapy of immune disorder diseases, prevention of organ transplantation rejection and tissue injury. In recent study, we demonstrated that MSCs in tumor inflammatory microenvironment might be elicited of immunosuppressive function. Thus, the application of MSCs in cancer therapy might have negative effect by helping tumor cells escaping from the immune surveillance.

  20. Complementation of a DNA repair defect in xeroderma pigmentosum cells by transfer of human chromosome 9

    International Nuclear Information System (INIS)

    Complementation of the repair defect in xeroderma pigmentosum cells of complementation group A was achieved by the transfer of human chromosome 9. A set of mouse-human hybrid cell lines, each containing a single Ecogpt-marked human chromosome, was used as a source of donor chromosomes. Chromosome transfer to XPTG-1 cells, a hypoxanthine/guanine phosphoribosyltransferase-deficient mutant of simian virus 40-transformed complementation group A cells, was achieved by microcell fusion and selection for Ecogpt. Chromosome-transfer clones of XPTG-1 cells, each containing a different human donor chromosome, were analyzed for complementation of sensitivity to UV irradiation. Among all the clones, increased levels of resistance to UV was observed only in clones containing chromosome 9. Since our recipient cell line XPTG-1 is hypoxanthine/guanine phosphoribosyltransferase deficient, cultivation of Ecogpt+ clones in medium containing 6-thioguanine permits selection of cells for loss of the marker and, by inference, transferred chromosome 9. Clones isolated for growth in 6-thioguanine, which have lost the Ecogpt-marked chromosome, exhibited a UV-sensitive phenotype, confirming the presence of the repair gene(s) for complementation group A on chromosome 9

  1. Oncolytic vaccinia therapy of squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Yu Yong A

    2009-07-01

    Full Text Available Abstract Background Novel therapies are necessary to improve outcomes for patients with squamous cell carcinomas (SCC of the head and neck. Historically, vaccinia virus was administered widely to humans as a vaccine and led to the eradication of smallpox. We examined the therapeutic effects of an attenuated, replication-competent vaccinia virus (GLV-1h68 as an oncolytic agent against a panel of six human head and neck SCC cell lines. Results All six cell lines supported viral transgene expression (β-galactosidase, green fluorescent protein, and luciferase as early as 6 hours after viral exposure. Efficient transgene expression and viral replication (>150-fold titer increase over 72 hrs were observed in four of the cell lines. At a multiplicity of infection (MOI of 1, GLV-1h68 was highly cytotoxic to the four cell lines, resulting in ≥ 90% cytotoxicity over 6 days, and the remaining two cell lines exhibited >45% cytotoxicity. Even at a very low MOI of 0.01, three cell lines still demonstrated >60% cell death over 6 days. A single injection of GLV-1h68 (5 × 106 pfu intratumorally into MSKQLL2 xenografts in mice exhibited localized intratumoral luciferase activity peaking at days 2–4, with gradual resolution over 10 days and no evidence of spread to normal organs. Treated animals exhibited near-complete tumor regression over a 24-day period without any observed toxicity, while control animals demonstrated rapid tumor progression. Conclusion These results demonstrate significant oncolytic efficacy by an attenuated vaccinia virus for infecting and lysing head and neck SCC both in vitro and in vivo, and support its continued investigation in future clinical trials.

  2. Mitochondrial respiratory modifiers confer survival advantage by facilitating DNA repair in cancer cells

    International Nuclear Information System (INIS)

    High rate of aerobic glycolysis (Warburg effect), one of the primary hallmarks of cancer cells, acquired during the multistep development of tumors is also responsible for therapeutic resistance. Underlying this hallmark is the compromised respiratory metabolism that contributes to the acquisition of the glycolytic phenotype for sustained ATP production and cell proliferation. Nevertheless, the exact mechanisms underlying the glycolysis-linked radio-resistance in cancer cells remain elusive. In this study, we transiently elevated glycolysis by treating human cell lines (HEK293, BMG-1 and OCT-1) with mitochondrial respiratory modifiers (MRMs) viz. 2,4-dinitrophenol, Photosan-3, and Methylene blue to examine if transient stimulation of glycolysis before irradiation using MRMs is sufficient to confer radioresistance. Treatment with MRMs led to a significant (two-fold) increase in glucose consumption and lactate production together with a robust increase in the protein levels of two key regulators of glucose metabolism, i.e. GLUT-1 and HK-II. MRMs also enhanced the clonogenic survival and facilitated DNA repair by activating both non-homologous end joining (NHEJ) and homologous recombination (HR) pathways of DNA double strand break repair leading to reduction in radiation-induced cytogenetic damage (micronuclei formation) in these cells. Inhibition of glucose uptake by inhibitors like 2-deoxy-D-glucose (2-DG), 3-bromo pyruvate (3-BP) and fasentin under conditions of stimulated glycolysis not only reversed the effect but also sensitized the cells to radiation more profoundly. The inhibition of glycolysis using 2-DG also reduced the levels of Ku 70 (NHEJ) and Rad-51 (HR) proteins. Thus, our results suggest that enhanced glycolysis in cancer cells may confer radio-resistance and offers survival advantage partly by enhancing the repair of DNA damage. (author)

  3. DNA Repair Genes ERCC1 and BRCA1 Expression in Non-Small Cell Lung Cancer Chemotherapy Drug Resistance.

    Science.gov (United States)

    Wang, Shuai; Liu, Feng; Zhu, Jingyan; Chen, Peng; Liu, Hongxing; Liu, Qi; Han, Junqing

    2016-01-01

    BACKGROUND Surgery combined with chemotherapy is an important therapy for non-small cell lung cancer (NSCLC). However, chemotherapy drug resistance seriously hinders the curative effect. Studies show that DNA repair genes ERCC1 and BRCA1 are associated with NSCLC chemotherapy, but their expression and mechanism in NSCLC chemotherapy drug-resistant cells has not been elucidated. MATERIAL AND METHODS NSCLC cell line A549 and drug resistance cell line A549/DDP were cultured. Real-time PCR and Western blot analyses were used to detect ERCC1 and BRCA1 mRNA expression. A549/DDP cells were randomly divided into 3 groups: the control group; the siRNA-negative control group (scramble group); and the siRNA ERCC1 and BRCA1siRNA transfection group. Real-time PCR and Western blot analyses were used to determine ERCC1 and BRCA1 mRNA and protein expression. MTT was used to detect cell proliferation activity. Caspase 3 activity was tested by use of a kit. Western blot analysis was performed to detect PI3K, AKT, phosphorylated PI3K, and phosphorylated AKT protein expression. RESULTS ERCC1 and BRCA1 were overexpressed in A549/DDP compared with A549 (PBRCA1 mRNA and protein expression (PBRCA1 expression obviously inhibited cell proliferation and increased caspase 3 activity (PBRCA1 significantly decreased PI3K and AKT phosphorylation levels (PBRCA1 were overexpressed in NSCLC drug-resistant cells, and they regulated lung cancer occurrence and development through the phosphorylating PI3K/AKT signaling pathway. PMID:27289442

  4. Altered Gene Expressions and Cytogenetic Repair Efficiency in Cells with Suppressed Expression of XPA after Proton Exposure

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Gridley, Daila S.; Mehta, Satish K.; Pierson, Duane L.; Wu, Honglu

    2009-01-01

    Cellular responses to damages from ionizing radiation (IR) exposure are influenced not only by the genes involved in DNA double strand break (DSB) repair, but also by non- DSB repair genes. We demonstrated previously that suppressed expression of several non-DSB repair genes, such as XPA, elevated IR-induced cytogenetic damages. In the present study, we exposed human fibroblasts that were treated with control or XPA targeting siRNA to 250 MeV protons (0 to 4 Gy), and analyzed chromosome aberrations and expressions of genes involved in DNA repair. As expected, after proton irradiation, cells with suppressed expression of XPA showed a significantly elevated frequency of chromosome aberrations compared with control siRNA treated (CS) cells. Protons caused more severe DNA damages in XPA knock-down cells, as 36% cells contained multiple aberrations compared to 25% in CS cells after 4Gy proton irradiation. Comparison of gene expressions using the real-time PCR array technique revealed that expressions of p53 and its regulated genes in irradiated XPA suppressed cells were altered similarly as in CS cells, suggesting that the impairment of IR induced DNA repair in XPA suppressed cells is p53-independent. Except for XPA, which was more than 2 fold down regulated in XPA suppressed cells, several other DNA damage sensing and repair genes (GTSE1, RBBP8, RAD51, UNG and XRCC2) were shown a more than 1.5 fold difference between XPA knock-down cells and CS cells after proton exposure. The possible involvement of these genes in the impairment of DNA repair in XPA suppressed cells will be further investigated.

  5. Chronic Spinal Injury Repair by Olfactory Bulb Ensheathing Glia and Feasibility for Autologous Therapy

    Science.gov (United States)

    Muñoz-Quiles, Cintia; Santos-Benito, Fernando F.; Llamusí, M. Beatriz; Ramón-Cueto, Almudena

    2009-01-01

    Olfactory bulb ensheathing glia (OB-OEG) promote repair of spinal cord injury (SCI) in rats after transplantation at acute or subacute (up to 45 days) stages. The most relevant clinical scenario in humans, however, is chronic SCI, in which no more major cellular or molecular changes occur at the injury site; this occurs after the third month in rodents. Whether adult OB-OEG grafts promote repair of severe chronic SCI has not been previously addressed. Rats with complete SCI that were transplanted with OB-OEG 4 months after injury exhibited progressive improvement in motor function and axonal regeneration from different brainstem nuclei across and beyond the SCI site. A positive correlation between motor outcome and axonal regeneration suggested a role for brainstem neurons in the recovery. Functional and histological outcomes did not differ at subacute or chronic stages. Thus, autologous transplantation is a feasible approach as there is time for patient stabilization and OEG preparation in human chronic SCI; the healing effects of OB-OEG on established injuries may offer new therapeutic opportunities for chronic SCI patients. PMID:19915486

  6. Cell-Autonomous Progeroid Changes in Conditional Mouse Models for Repair Endonuclease XPG Deficiency

    Science.gov (United States)

    Vermeij, Wilbert P.; Tresini, Maria; Weymaere, Michael; Menoni, Hervé; Brandt, Renata M. C.; de Waard, Monique C.; Botter, Sander M.; Sarker, Altaf H.; Jaspers, Nicolaas G. J.; van der Horst, Gijsbertus T. J.; Cooper, Priscilla K.; Hoeijmakers, Jan H. J.; van der Pluijm, Ingrid

    2014-01-01

    As part of the Nucleotide Excision Repair (NER) process, the endonuclease XPG is involved in repair of helix-distorting DNA lesions, but the protein has also been implicated in several other DNA repair systems, complicating genotype-phenotype relationship in XPG patients. Defects in XPG can cause either the cancer-prone condition xeroderma pigmentosum (XP) alone, or XP combined with the severe neurodevelopmental disorder Cockayne Syndrome (CS), or the infantile lethal cerebro-oculo-facio-skeletal (COFS) syndrome, characterized by dramatic growth failure, progressive neurodevelopmental abnormalities and greatly reduced life expectancy. Here, we present a novel (conditional) Xpg−/− mouse model which -in a C57BL6/FVB F1 hybrid genetic background- displays many progeroid features, including cessation of growth, loss of subcutaneous fat, kyphosis, osteoporosis, retinal photoreceptor loss, liver aging, extensive neurodegeneration, and a short lifespan of 4–5 months. We show that deletion of XPG specifically in the liver reproduces the progeroid features in the liver, yet abolishes the effect on growth or lifespan. In addition, specific XPG deletion in neurons and glia of the forebrain creates a progressive neurodegenerative phenotype that shows many characteristics of human XPG deficiency. Our findings therefore exclude that both the liver as well as the neurological phenotype are a secondary consequence of derailment in other cell types, organs or tissues (e.g. vascular abnormalities) and support a cell-autonomous origin caused by the DNA repair defect itself. In addition they allow the dissection of the complex aging process in tissue- and cell-type-specific components. Moreover, our data highlight the critical importance of genetic background in mouse aging studies, establish the Xpg−/− mouse as a valid model for the severe form of human XPG patients and segmental accelerated aging, and strengthen the link between DNA damage and aging. PMID:25299392

  7. Cell-autonomous progeroid changes in conditional mouse models for repair endonuclease XPG deficiency.

    Directory of Open Access Journals (Sweden)

    Sander Barnhoorn

    2014-10-01

    Full Text Available As part of the Nucleotide Excision Repair (NER process, the endonuclease XPG is involved in repair of helix-distorting DNA lesions, but the protein has also been implicated in several other DNA repair systems, complicating genotype-phenotype relationship in XPG patients. Defects in XPG can cause either the cancer-prone condition xeroderma pigmentosum (XP alone, or XP combined with the severe neurodevelopmental disorder Cockayne Syndrome (CS, or the infantile lethal cerebro-oculo-facio-skeletal (COFS syndrome, characterized by dramatic growth failure, progressive neurodevelopmental abnormalities and greatly reduced life expectancy. Here, we present a novel (conditional Xpg-/- mouse model which -in a C57BL6/FVB F1 hybrid genetic background- displays many progeroid features, including cessation of growth, loss of subcutaneous fat, kyphosis, osteoporosis, retinal photoreceptor loss, liver aging, extensive neurodegeneration, and a short lifespan of 4-5 months. We show that deletion of XPG specifically in the liver reproduces the progeroid features in the liver, yet abolishes the effect on growth or lifespan. In addition, specific XPG deletion in neurons and glia of the forebrain creates a progressive neurodegenerative phenotype that shows many characteristics of human XPG deficiency. Our findings therefore exclude that both the liver as well as the neurological phenotype are a secondary consequence of derailment in other cell types, organs or tissues (e.g. vascular abnormalities and support a cell-autonomous origin caused by the DNA repair defect itself. In addition they allow the dissection of the complex aging process in tissue- and cell-type-specific components. Moreover, our data highlight the critical importance of genetic background in mouse aging studies, establish the Xpg-/- mouse as a valid model for the severe form of human XPG patients and segmental accelerated aging, and strengthen the link between DNA damage and aging.

  8. Gene-specific repair of benzo[a]pyrene diol epoxide DNA damage in human cells

    International Nuclear Information System (INIS)

    Gene-specific preferential repair of UV damage has been well documented in a variety of organisms. Less is known about many other types of critical DNA lesions, the data available being not numerous and contradictory. To date, the majority of observations with UV were obtained by using T4 endonuclease V system. Recent report questions the applicability of UvrABC nuclease incision method for detecting gene-specific repair. This has stimulated our search for simple and sensitive approach based on a different principle. We have employed the idea of detection by the Southern hybridization of restriction cleavage inhibition at rare sites and developed a method for the analysis of benzo[a]pyrene diol epoxide (anti-BPDE) DNA damage in human H-ras proto-oncogene. Damage-dependent induction of individual facultative bands resulting from cleavage inhibition was observed in in vitro modified (4-50 adducts/103kb) p220-ras plasmid DNA digested with EcoRI/NotI, Xhol/Xbal/PstI, and SstI/XbaI/Pst/I. In vivo lesion formation and removal was monitored at several PstI sites distributed along the 6.4 kb single copy ras sequence. Rapid gene-specific repair was seen in primary culture of normal human fibroblasts and in SV40 transformed GM00637 cells. Surprisingly, SV40 transformed XP12BE (complementation group A) GM4429 fibroblasts also repaired anti-BPDE DNA damage at comparable levels. All investigated sites within ras sequence were repaired faster than the genome overall. The results show the utility of the above approach for fine mapping of anti-BPDE DNA lesions. Data suggests that the xeroderma pigmentosum (group A) fibroblasts have a capacity of removing these bulky adducts at least from the active genes

  9. Carcinogen-induced DNA repair in nucleotide-permeable Escherichia coli cells. Induction of DNA repair by the carcinogens methyl and ethyl nitrosourea and methyl methanesulfonate.

    Science.gov (United States)

    Thielmann, H W; Vosberg, H P; Reygers, U

    1975-08-15

    Ether-permeabilized (nucleotide-permeable) cells of Escherichia coli show excision repair of their DNA after having been exposed to the carcinogens N-methyl-N-nitrosourea (MeNOUr), N-ethyl-N-nitrosourea (EtNOUr) and methyl methanesulfonate (MeSO2OMe) which are known to bind covalently to DNA. Defect mutations in genes uvrA, uvrB, uvrC, recA, recB, recC and rep did not inhibit this excision repair. Enzymic activities involved in this repair were identified by measuring size reduction of DNA, DNA degradation to acid-soluble nucleotides and repair polymerization. 1. In permeabilized cells methyl and ethyl nitrosourea induced endonucleolytic cleavage of endogenous DNA, as determined by size reduction of denatured DNA in neutral and alkaline sucrose gradients. An enzymic activity from E. coli K-12 cell extracts was purified (greater than 2000-fold) and was found to cleave preferentially methyl-nitrosourea-treated DNA and to convert the methylated supercoiled DNA duplex (RFI) of phage phiX 174 into the nicked circular form. 2. Degradation of alkylated cellular DNA to acid solubility was diminished in a mutant lacking the 5' leads to 3' exonucleolytic activity of DNA polymerase I but was not affected in a mutant which lacked the DNA polymerizing but retained the 5' leads 3' exonucleolytic activity of DNA polymerase I. 3. An easily measurable effect is carcinogen-induced repair polymerization, making it suitable for detection of covalent binding of carcinogens and potentially carcinogenic compounds. PMID:170107

  10. The Cell Therapy Catapult: growing a U.K. cell therapy industry generating health and wealth.

    Science.gov (United States)

    Thompson, Keith; Foster, Emma Palmer

    2013-12-01

    In a recent report on the regenerative medicine sector, the U.K. House of Lords made several recommendations to enable the United Kingdom to become a global leader in this important industry. Its recommendations in this regard were many and various, covering the regulatory system, clinical trials, manufacturing, funding, approval, and reimbursement. In its mission to tackle what it sees as three main types of barriers to the development of the cell therapy industry in the United Kingdom, the Cell Therapy Catapult is tackling many of these issues. Established as a center of excellence in the United Kingdom in 2012, the Cell Therapy Catapult is a research organization expected to grow to a team of around 100 experts. Its core financing of £ 70 million over the next 5 years is provided by the Technology Strategy Board, the United Kingdom's innovation agency, and with additional contract research income and access to collaborative funds, the Catapult expects to build up to annual revenues of around £ 30 million. Along with its sister Catapult programs in other areas of the economy, the Cell Therapy Catapult was established after identification of the massive early-stage expertise the country has, as well as an acute market failure-the lack of expertise to translate early-stage cell therapy research into commercial success. In this article, in addition to showing our progress so far, we will discuss the hurdles the industry faces-grouped into business, manufacturing/supply chain issues, and clinical/regulatory issues-and what we are doing to help the United Kingdom leap over them. PMID:24304073

  11. Mesenchymal stem cells for repair of the airway epithelium in asthma.

    Science.gov (United States)

    Knight, Darryl A; Rossi, Fabio M; Hackett, Tillie-Louise

    2010-12-01

    The airway epithelium is constantly faced with inflammatory and potentially injurious stimuli. Following damage, rapid repair mechanisms involving proliferation and differentiation of resident progenitor and stem cell pools are necessary in order to maintain a protective barrier. In asthma, evidence pointing to a compromised ability of the epithelium to properly repair and regenerate is rapidly accumulating. The consequences of this are presently unknown but are likely to have a significant impact on lung function. Mesenchymal stem cells have the potential to serve as a universal source for replacement of specific cells in several diseases and thus offer hope as a potential therapeutic intervention for the treatment of the chronic remodeling changes that occur in the asthmatic epithelium. However, controversy exists regarding whether these cells can actually home to and engraft within the airways and contribute to tissue function or whether this mechanism is necessary, since they can have potent paracrine immunomodulatory effects. This article focuses on the current knowledge about specific stem cell populations that may contribute to airway epithelial regeneration and discusses the use of mesenchymal stem cells as a potential therapeutic intervention. PMID:21128750

  12. Present and future cell therapies for pancreatic beta cell replenishment

    OpenAIRE

    Domínguez-Bendala, Juan; Ricordi, Camillo

    2012-01-01

    If only at a small scale, islet transplantation has successfully addressed what ought to be the primary endpoint of any cell therapy: the functional replenishment of damaged tissue in patients. After years of less-than-optimal approaches to immunosuppression, recent advances consistently yield long-term graft survival rates comparable to those of whole pancreas transplantation. Limited organ availability is the main hurdle that stands in the way of the widespread clinical utilization of this ...

  13. Radiation damage and repair in cells and cell components. Final report. Part 1

    International Nuclear Information System (INIS)

    An overview of research into the direct action of ionizing radiation, especially the effect of radiation temperature, primarily upon enzymes, into induced repair, and into S.O.S.-related phenomena, is presented

  14. Radiation damage and repair in cells and cell components. Progress report: third new contract year

    International Nuclear Information System (INIS)

    Research progress for 1979-1980 is reported. Projects discussed include the process of radiation-induced repair, Weigle-reactivation, induced radioresistance, the induction of the recA gene product, uv mutagenesis, and the induction of lambda

  15. Managing particulates in cell therapy: Guidance for best practice.

    Science.gov (United States)

    Clarke, Dominic; Stanton, Jean; Powers, Donald; Karnieli, Ohad; Nahum, Sagi; Abraham, Eytan; Parisse, Jean-Sebastien; Oh, Steve

    2016-09-01

    The intent of this article is to provide guidance and recommendations to cell therapy product sponsors (including developers and manufacturers) and their suppliers in the cell therapy industry regarding particulate source, testing, monitoring and methods for control. This information is intended to help all parties characterize the processes that generate particulates, understand product impact and provide recommendations to control particulates generated during manufacturing of cell therapy products. PMID:27426934

  16. Maggot therapy for repairing serious infective wound in a severely burned patient

    Directory of Open Access Journals (Sweden)

    WU Jun-cheng

    2012-04-01

    Full Text Available 【Abstract】The larvae of musca domestica were put in use to discard the dead tissue of a case of severe burn. A total of 50 000 aseptic maggots were put onto the infective wound surface, and aseptic dressings overlaid the surface. Three days later, another 20 000 maggots were put onto the wound for the second therapy. After twice maggot debridement, most necrotic muscle tissues of the wound were cleaned up, and eventually fresh granulation tissue grew and later the wound was covered and healed by 3 times of skin grafting. The result demonstrates that maggot therapy is safe and effective with no adverse complications except pain. Key words: Biological therapy; Wound infection; Burns; Wound healing; Debridement

  17. Two New Faces of Amifostine: Protector from DNA Damage in Normal Cells and Inhibitor of DNA Repair in Cancer Cells.

    Science.gov (United States)

    Hofer, Michal; Falk, Martin; Komůrková, Denisa; Falková, Iva; Bačíková, Alena; Klejdus, Bořivoj; Pagáčová, Eva; Štefančíková, Lenka; Weiterová, Lenka; Angelis, Karel J; Kozubek, Stanislav; Dušek, Ladislav; Galbavý, Štefan

    2016-04-14

    Amifostine protects normal cells from DNA damage induction by ionizing radiation or chemotherapeutics, whereas cancer cells typically remain uninfluenced. While confirming this phenomenon, we have revealed by comet assay and currently the most sensitive method of DNA double strand break (DSB) quantification (based on γH2AX/53BP1 high-resolution immunofluorescence microscopy) that amifostine treatment supports DSB repair in γ-irradiated normal NHDF fibroblasts but alters it in MCF7 carcinoma cells. These effects follow from the significantly lower activity of alkaline phosphatase measured in MCF7 cells and their supernatants as compared with NHDF fibroblasts. Liquid chromatography-mass spectrometry confirmed that the amifostine conversion to WR-1065 was significantly more intensive in normal NHDF cells than in tumor MCF cells. In conclusion, due to common differences between normal and cancer cells in their abilities to convert amifostine to its active metabolite WR-1065, amifostine may not only protect in multiple ways normal cells from radiation-induced DNA damage but also make cancer cells suffer from DSB repair alteration. PMID:26978566

  18. [Retinal Cell Therapy Using iPS Cells].

    Science.gov (United States)

    Takahashi, Masayo

    2016-03-01

    Progress in basic research, starting with the work on neural stem cells in the middle 1990's to embryonic stem (ES) cells and induced pluripotent stem (iPS) cells at present, will lead the cell therapy (regenerative medicine) of various organs, including the central nervous system to a big medical field in the future. The author's group transplanted iPS cell-derived retinal pigment epithelial (RPE) cell sheets to the eye of a patient with exudative age-related macular degeneration (AMD) in 2014 as a clinical research. Replacement of the RPE with the patient's own iPS cell-derived young healthy cell sheet will be one new radical treatment of AMD that is caused by cellular senescence of RPE cells. Since it was the first clinical study using iPS cell-derived cells, the primary endpoint was safety judged by the outcome one year after surgery. The safety of the cell sheet has been confirmed by repeated tumorigenisity tests using immunodeficient mice, as well as purity of the cells, karyotype and genetic analysis. It is, however, also necessary to prove the safety by clinical studies. Following this start, a good strategy considering cost and benefit is needed to make regenerative medicine a standard treatment in the future. Scientifically, the best choice is the autologous RPE cell sheet, but autologous cell are expensive and sheet transplantation involves a risky part of surgical procedure. We should consider human leukocyte antigen (HLA) matched allogeneic transplantation using the HLA 6 loci homozyous iPS cell stock that Prof. Yamanaka of Kyoto University is working on. As the required forms of donor cells will be different depending on types and stages of the target diseases, regenerative medicine will be accomplished in a totally different manner from the present small molecule drugs. Proof of concept (POC) of photoreceptor transplantation in mouse is close to being accomplished using iPS cell-derived photoreceptor cells. The shortest possible course for treatment

  19. Identification of Drugs that Regulate Dermal Stem Cells and Enhance Skin Repair

    Directory of Open Access Journals (Sweden)

    Sibel Naska

    2016-01-01

    Full Text Available Here, we asked whether we could identify pharmacological agents that enhance endogenous stem cell function to promote skin repair, focusing on skin-derived precursors (SKPs, a dermal precursor cell population. Libraries of compounds already used in humans were screened for their ability to enhance the self-renewal of human and rodent SKPs. We identified and validated five such compounds, and showed that two of them, alprostadil and trimebutine maleate, enhanced the repair of full thickness skin wounds in middle-aged mice. Moreover, SKPs isolated from drug-treated skin displayed long-term increases in self-renewal when cultured in basal growth medium without drugs. Both alprostadil and trimebutine maleate likely mediated increases in SKP self-renewal by moderate hyperactivation of the MEK-ERK pathway. These findings identify candidates for potential clinical use in human skin repair, and provide support for the idea that pharmacological activation of endogenous tissue precursors represents a viable therapeutic strategy.

  20. Concerted control of DNA double strand break repair and cell cycle progression in X-irradiated mammalian cells

    International Nuclear Information System (INIS)

    Upon examination of cell cycle regulation in a damaged cell, relations were discovered of the cell cycle control mechanisms with a complicated web of signalling pathways, eventually called the genome surveillance system. After infliction of DNA double strand breaks (DSB), the signalling is initiated by sensor proteins and transducer protein kinase ATM. This kinase phosphorylates downstream effector proteins, such as checkpoint kinases CHK1 and CHK2, which initiate the pathways leading to cell cycle arrest. In contrast with the older model of linear transmission of signals in a certain sequence, it is now accepted that the damage signalling system is branched and contains feedback loops. DSB's presence is signalled by sensor proteins (MRE11-RAD50-nibrin complex, MRN) to ATM and the signal is amplified through adaptor proteins, MDC1/NFBD1 or 53BP1 (Tp53 binding protein). MRN contains a forkheadassociated (FHA) domain and BRCA1 carboxyl-terminal (BRCT) domain. The combination of the FHA/BRCT domains has a crucial role for the binding of nibrin to the H2AX histone, assembling the components of repair foci. These domains also are important for interaction of other proteins localised in the foci. For example, MDC1/NFBD1 contains a FHA domain and two BRCT domains which are involved in protein interactions. The signal generated at DSBs is amplified and transduced to recruit components of DNA repair systems. In a concerted way with the sequential recruitment of components of repair foci, activation of transcription of genes takes place, that is necessary for blocking progression through the cell cycle, for DNA repair or apoptosis. (author)

  1. Maggot therapy for repairing serious infective wound in a severely burned patient.

    Science.gov (United States)

    Wu, Jun-Cheng; Lu, Ren-Rong; Huo, Ran; Fu, Hong-Bin

    2012-01-01

    The larvae of musca domestica were put in use to discard the dead tissue of a case of severe burn. A total of 50 000 aseptic maggots were put onto the infective wound surface, and aseptic dressings overlaid the surface. Three days later, another 20 000 maggots were put onto the wound for the second therapy. After twice maggot debridement, most necrotic muscle tissues of the wound were cleaned up, and eventually fresh granulation tissue grew and later the wound was covered and healed by 3 times of skin grafting. The result demonstrates that maggot therapy is safe and effective with no adverse complications except pain. PMID:22480679

  2. Increasing Melanoma—Too Many Skin Cell Damages or Too Few Repairs?

    Directory of Open Access Journals (Sweden)

    Örjan Hallberg

    2013-02-01

    Full Text Available Skin melanoma rates have been increasing for a long time in many Western countries. The object of this study was to apply modern problem-solving theory normally used to clear industrial problems to search for roots and causes of this medical question. Increasing cancer rates can be due to too many cell damage incidents or to too few repairs. So far, it has been assumed that the melanoma epidemic mainly is caused by increasing sun tanning habits. In order to explore this problem in more detail, we used cancer statistics from several countries over time and space. Detailed analysis of data obtained and a model study to evaluate the effects from increased damages or decreased repairs clearly indicate that the main reason behind the melanoma problem is a disturbed immune system. The possibility to introduce efficient corrective actions is apparent.

  3. Low-level laser (light) therapy (LLLT) on muscle tissue: performance, fatigue and repair benefited by the power of light

    OpenAIRE

    Ferraresi, Cleber; Hamblin, Michael R.; Parizotto, Nivaldo A.

    2012-01-01

    The use of low level laser (light) therapy (LLLT) has recently expanded to cover areas of medicine that were not previously thought of as the usual applications such as wound healing and inflammatory orthopedic conditions. One of these novel application areas is LLLT for muscle fatigue and muscle injury. Since it is becoming agreed that mitochondria are the principal photoacceptors present inside cells, and it is known that muscle cells are exceptionally rich in mitochondria, this suggests th...

  4. Overexpression of DNA ligase III in mitochondria protects cells against oxidative stress and improves mitochondrial DNA base excision repair

    DEFF Research Database (Denmark)

    Akbari, Mansour; Keijzers, Guido; Maynard, Scott;

    2014-01-01

    Base excision repair (BER) is the most prominent DNA repair pathway in human mitochondria. BER also results in a temporary generation of AP-sites, single-strand breaks and nucleotide gaps. Thus, incomplete BER can result in the generation of DNA repair intermediates that can disrupt mitochondrial...... rotenone. Our results suggest that the amount of DNA ligase III in mitochondria may be critical for cell survival following prolonged oxidative stress, and demonstrate a functional link between mitochondrial DNA damage and repair, cell survival upon oxidative stress, and removal of dysfunctional...... DNA replication and transcription and generate mutations. We carried out BER analysis in highly purified mitochondrial extracts from human cell lines U2OS and HeLa, and mouse brain using a circular DNA substrate containing a lesion at a specific position. We found that DNA ligation is significantly...

  5. The role of stem cells in airway repair: implications for the origins of lung cancer

    Institute of Scientific and Technical Information of China (English)

    Michael S.Mulvihill; Johannes R.Kratz; Patrick Pham; David M.Jablons; Biao He

    2013-01-01

    Lung cancer is the leading cause of cancer-related deaths worldwide.Recently,advancements in our ability to identify and study stem cell populations in the lung have helped researchers to elucidate the central role that cells with stem cell-like properties may have in lung tumorigenesis.Much of this research has focused on the use of the airway repair model to study response to injury.In this review,we discuss the primary evidence of the role that cancer stem cells play in lung cancer development.The implications of a stem cell origin of lung cancer are reviewed,and the importance of ongoing research to identify novel therapeutic and prognostic targets is reiterated.

  6. The role of stem cells in airway repair: implications for the origins of lung cancer

    Directory of Open Access Journals (Sweden)

    Michael S. Mulvihill

    2013-02-01

    Full Text Available Lung cancer is the leading cause of cancer-related deaths worldwide. Recently, advancements in our ability to identify and study stem cell populations in the lung have helped researchers to elucidate the central role that cells with stem cell-like properties may have in lung tumorigenesis. Much of this research has focused on the use of the airway repair model to study response to injury. In this review, we discuss the primary evidence of the role that cancer stem cells play in lung cancer development. The implications of a stem cell origin of lung cancer are reviewed, and the importance of ongoing research to identify novel therapeutic and prognostic targets is reiterated.

  7. Stem Cell Therapy: A New Treatment for Burns?

    OpenAIRE

    Gauglitz, Gerd G.; Marc G. Jeschke; Mohammed Al Shehab; Anna Arno; Blit, Patrick H.; Smith, Alexandra H.

    2011-01-01

    Stem cell therapy has emerged as a promising new approach in almost every medicine specialty. This vast, heterogeneous family of cells are now both naturally (embryonic and adult stem cells) or artificially obtained (induced pluripotent stem cells or iPSCs) and their fates have become increasingly controllable, thanks to ongoing research in this passionate new field. We are at the beginning of a new era in medicine, with multiple applications for stem cell therapy, not only as a monotherapy, ...

  8. Adoptive T cell therapy: Addressing challenges in cancer immunotherapy

    Directory of Open Access Journals (Sweden)

    Yee Cassian

    2005-04-01

    Full Text Available Abstract Adoptive T cell therapy involves the ex vivo selection and expansion of effector cells for the treatment of patients with cancer. In this review, the advantages and limitations of using antigen-specific T cells are discussed in counterpoint to vaccine strategies. Although vaccination strategies represent more readily available reagents, adoptive T cell therapy provides highly selected T cells of defined phenotype, specificity and function that may influence their biological behavior in vivo. Adoptive T cell therapy offers not only translational opportunities but also a means to address fundamental issues in the evolving field of cancer immunotherapy.

  9. A modified fluorimetric host cell reactivation assay to determine the repair capacity of primary keratinocytes, melanocytes and fibroblasts

    Directory of Open Access Journals (Sweden)

    Gebhard Daniel

    2010-06-01

    Full Text Available Abstract Background The Host Cell Reactivation Assay (HCRA is widely used to identify circumstances and substances affecting the repair capacity of cells, however, it is restricted by the transfection procedure used and the sensitivity of the detection method. Primary skin cells are particularly difficult to transfect, and therefore sensitive methods are needed to detect any variations due to the cell-type or inter-individual differences or changes induced by diverse substances. A sensitive and repeatable method to detect the repair capacity of skin cells would be useful in two different aspects: On the one hand, to identify substances influencing the repair capacity in a positive manner (these substances could be promising ingredients for cosmetic products and on the other hand, to exclude the negative effects of substances on the repair capacity (this could serve as one step further towards replacing or at least reducing animal testing. Results In this paper, we present a rapid and sensitive assay to determine the repair capacity of primary keratinocytes, melanocytes and fibroblasts based on two wave-length Green Fluorescent Protein (GFP and DsRed reporter technology in order to test different substances and their potential to influence the DNA repair capacity. For the detection of plasmid restoration, we used FACS technology, which, in comparison to luminometer technology, is highly sensitive and allows single cell based analysis. The usefulness of this assay and studying the repair capacity is demonstrated by the evidence that DNA repair is repressed by Cyclosporin A in fibroblasts. Conclusions The methodology described in this paper determines the DNA repair capacity in different types of human skin cells. The described transfection protocol is suitable for the transfection of melanocytes, keratinocytes and fibroblasts, reaching efficacies suitable for the detection of the restored plasmids by FACS technology. Therefore the repair capacity

  10. Low Reactive Level Laser Therapy for Mesenchymal Stromal Cells Therapies

    OpenAIRE

    Toshihiro Kushibiki; Takeshi Hirasawa; Shinpei Okawa; Miya Ishihara

    2015-01-01

    Low reactive level laser therapy (LLLT) is mainly focused on the activation of intracellular or extracellular chromophore and the initiation of cellular signaling by using low power lasers. Over the past forty years, it was realized that the laser therapy had the potential to improve wound healing and reduce pain and inflammation. In recent years, the term LLLT has become widely recognized in the field of regenerative medicine. In this review, we will describe the mechanisms of action of LLLT...

  11. Dictyostelium discoideum, a lower eukaryote model for the study of DNA repair: Implications for the role of DNA-damaging chemicals in the evolution of repair proficient cells

    Science.gov (United States)

    Deering, R. A.

    1994-10-01

    The evolution of the ability of living cells to cope with stress is crucial for the maintenance of their genetic integrity. Yet low levels of mutation must remain to allow adaptation to environmental changes. The cellular slime mold D. discoideum is a good system for studying molecular aspects of the repair of lethal and mutagenic damage to DNA by radiation and chemicals. The wild-type strains of this soil microorganism are extremely resistant to DNA damaging agents. In nature the amoeboid cells in their replicative stage feed on soil bacteria and are exposed to numerous DNA-damaging chemicals produced by various soil microorganisms. It is probable that the evolution of repair systems in this organism and perhaps in others is a consequence of the necessity to cope with chemical damage which also confers resistance to radiation.

  12. DNA repair efficiency in germ cells and early mouse embryos and consequences for radiation-induced transgenerational genomic damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Wyrobek, Andrew J.

    2009-01-18

    Exposure to ionizing radiation and other environmental agents can affect the genomic integrity of germ cells and induce adverse health effects in the progeny. Efficient DNA repair during gametogenesis and the early embryonic cycles after fertilization is critical for preventing transmission of DNA damage to the progeny and relies on maternal factors stored in the egg before fertilization. The ability of the maternal repair machinery to repair DNA damage in both parental genomes in the fertilizing egg is especially crucial for the fertilizing male genome that has not experienced a DNA repair-competent cellular environment for several weeks prior to fertilization. During the DNA repair-deficient period of spermatogenesis, DNA lesions may accumulate in sperm and be carried into the egg where, if not properly repaired, could result in the formation of heritable chromosomal aberrations or mutations and associated birth defects. Studies with female mice deficient in specific DNA repair genes have shown that: (i) cell cycle checkpoints are activated in the fertilized egg by DNA damage carried by the sperm; and (ii) the maternal genotype plays a major role in determining the efficiency of repairing genomic lesions in the fertilizing sperm and directly affect the risk for abnormal reproductive outcomes. There is also growing evidence that implicates DNA damage carried by the fertilizing gamete as a mediator of postfertilization processes that contribute to genomic instability in subsequent generations. Transgenerational genomic instability most likely involves epigenetic mechanisms or error-prone DNA repair processes in the early embryo. Maternal and embryonic DNA repair processes during the early phases of mammalian embryonic development can have far reaching consequences for the genomic integrity and health of subsequent generations.

  13. Modification of radiation response in mammalian cells: the repair and fixation of x-ray induced potentially lethal damage

    International Nuclear Information System (INIS)

    The effects of anisotonic salt treatments, polyamines, dimethyl sulfoxide (DMSO), 5'-bromodeoxyuridine (BrdUrd) and hyperthermia on the repair and fixation of X-ray-induced radiation damage were examined in V79 Chinese hamster lung fibroblasts, Chinese hamster ovary cells, normal and ataxia telangiectasis (AT) human cells. Significant repair of potentially lethal damage (PLD) was observed when cells were held in Earle's balanced salt solutions, or in plateau phase, following exposure to X-radiation; a much greater recovery was observed when cells were incubated at 37 degrees C between irradiation and subsequent exposure to anisotonic salts. Cells exposed to 1 or 2 mol/L DMSO or 10-5 mol/L BrdUrd exhibited PLD repair patterns comparable to control cells. Contrary to the results of others, human AT homozygotes, like normal human cells, did sustain radiation damage that could be fixed or repaired by anisotonic salt treatment. The extent of damage fixation was dose-dependent and was observed at doses as low as 0.25 Gy. A greater degree of PLD was fixed when cells were irradiated at 0 degrees C rather than 37 degrees C, suggesting that repair occurs during irradiation. While heat damage was not susceptible to fixation by anisotonic salt treatment, the synergistic enhancement of X-ray damage due to heat was fixed in a pattern dependent on the heating temperature

  14. Systemic adjuvant therapies in renal cell carcinoma.

    Science.gov (United States)

    Buti, Sebastiano; Bersanelli, Melissa; Donini, Maddalena; Ardizzoni, Andrea

    2012-10-01

    Renal cell carcinoma (RCC) is one of the ten most frequent solid tumors worldwide. Recent innovations in the treatment of metastatic disease have led to new therapeutic approaches being investigated in the adjuvant setting. Observation is the only current standard of care after radical nephrectomy, although there is evidence of efficacy of adjuvant use of vaccine among all the strategies used. This article aims to collect published experiences with systemic adjuvant approaches in RCC and to describe the results of past and ongoing phase III clinical trials in this field. We explored all the systemic treatments, including chemotherapy, immunotherapy and targeted drugs while alternative approaches have also been described. Appropriate selection of patients who would benefit from adjuvant therapies remains a crucial dilemma. Although the international guidelines do not actually recommend any adjuvant treatment after radical surgery for RCC, no conclusions have yet been drawn pending the results of the promising ongoing clinical trials with the target therapies. The significant changes that these new drugs have made on advanced disease outcome could represent the key to innovation in terms of preventing recurrence, delaying relapse and prolonging survival after radical surgery for RCC. PMID:25992216

  15. Systemic adjuvant therapies in renal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Sebastiano Buti

    2012-10-01

    Full Text Available Renal cell carcinoma (RCC is one of the ten most frequent solid tumors worldwide. Recent innovations in the treatment of metastatic disease have led to new therapeutic approaches being investigated in the adjuvant setting. Observation is the only current standard of care after radical nephrectomy, although there is evidence of efficacy of adjuvant use of vaccine among all the strategies used. This article aims to collect published experiences with systemic adjuvant approaches in RCC and to describe the results of past and ongoing phase III clinical trials in this field. We explored all the systemic treatments, including chemotherapy, immunotherapy and targeted drugs while alternative approaches have also been described. Appropriate selection of patients who would benefit from adjuvant therapies remains a crucial dilemma. Although the international guidelines do not actually recommend any adjuvant treatment after radical surgery for RCC, no conclusions have yet been drawn pending the results of the promising ongoing clinical trials with the target therapies. The significant changes that these new drugs have made on advanced disease outcome could represent the key to innovation in terms of preventing recurrence, delaying relapse and prolonging survival after radical surgery for RCC.

  16. Ongoing studies of cell-based therapies for articular cartilage defects in Japan

    Directory of Open Access Journals (Sweden)

    Ogura T

    2014-12-01

    Full Text Available Takahiro Ogura,1 Akihiro Tsuchiya,2 Shuichi Mizuno1 1Department of Orthopedic Surgery, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA, USA; 2Funabashi Orthopaedic Hospital Sports Medicine Center, Funabashi, Chiba, Japan Abstract: Recently, cell-based therapies have generated great interest in the repair of articular cartilage defects and degeneration. Surgical treatments for these indications have multiple options, including marrow stimulation, osteochondral autograft transplant, and autologous chondrocyte implantation. The autologous chondrocyte implantation technique has been improved using a cell scaffold and other devices. Meanwhile, advanced cell-based therapies, including cultured stem cell treatment, have been studied in clinical trials. Most studies have been designed and authorized by institutional review boards and/or the regulatory agencies of the investigators’ countries. For cellular products in regenerative medicine, regulations of many countries are amenable to expedited approval. This paper aims to provide an update on ongoing and prospective cell-based therapies, focusing on articular cartilage injury at designated institutions authorized by the Japanese Pharmaceutical and Medical Device Agency. Keywords: autologous chondrocyte implantation, mesenchymal stem cell, knee joint

  17. DNA repair mechanisms of tumor cells and chemotherapy sensitivity%肿瘤细胞DNA损伤修复机制与化疗敏感性

    Institute of Scientific and Technical Information of China (English)

    张朋军

    2008-01-01

    DNA damage caused by chemotherapeutic drugs plays an important role in the tumor chemo- therapy.The DNA repair pathways that are activated in response to DNA damage induce resistance to chemo-therapeutic drugs or radiation and depress the effect of these agents on tumor cells.Down-regulated DNA repair capacity has shown a better effect through inducing tumor cell hypersensitivity to chemotherapeutic drugs.It has emerged as an important comprehensive approach by down-regulated expression of DNA repair genes in the treatment of cancer.%在肿瘤化疗中,药物所致DNA损伤起着极其重要的作用.其损伤很大程度上刺激了DNA修复能力的增强,从而严重制约化疗药物的药效.而DNA修复能力的下降可使肿瘤细胞对药物产生超敏反应,达到更好的辅助化疗效果.因此作为一种辅助化疗的方法可以通过改变基因使肿瘤细胞DNA修复能力下降.

  18. Sequential Therapy in Metastatic Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Bradford R Hirsch

    2016-04-01

    Full Text Available The treatment of metastatic renal cell carcinoma (mRCC has changed dramatically in the past decade. As the number of available agents, and related volume of research, has grown, it is increasingly complex to know how to optimally treat patients. The authors are practicing medical oncologists at the US Oncology Network, the largest community-based network of oncology providers in the country, and represent the leadership of the Network's Genitourinary Research Committee. We outline our thought process in approaching sequential therapy of mRCC and the use of real-world data to inform our approach. We also highlight the evolving literature that will impact practicing oncologists in the near future.

  19. DNA mismatch repair efficiency and fidelity are elevated during DNA synthesis in human cells

    International Nuclear Information System (INIS)

    DNA mismatch repair (MMR) within human cells is hypothesized to occur primarily at the replication fork. However, experimental models measuring MMR activity at specific phases of the cell cycle and during genomic DNA synthesis are lacking. We have investigated MMR activity within the nuclear environment of HeLa cells after enriching for G1, S and G2/M phase of the cell cycle by centrifugal elutriation. This approach preserves physiologically normal MMR activity in cell populations subdivided into different phases of the cell cycle. Here we have shown that nuclear protein concentration of hMutSα and hMutLα increases as cells progress into S phase during routine cell culture. MMR activity, as measured by both in vitro and in vivo approaches, increases during S phase to the highest extent within normally growing cells. Both fidelity and activity of MMR are highest on actively replicating templates within intact cells during S phase. The MMR pathway however, is also active at lower levels at other phases of the cell cycle, and on nonreplicating templates

  20. Maggot therapy for repairing serious infective wound in a severely burned patient

    Institute of Scientific and Technical Information of China (English)

    WU Jun-cheng; LU Ren-rong; HUO Ran; FU Hong-bin

    2012-01-01

    The larvae of musca domestica were put in use to discard the dead tissue of a case of severe burn.A total of 50 000 aseptic maggots were put onto the infective wound surface,and aseptic dressings overlaid the surface.Three days later,another 20 000 maggots were put onto the wound for the second therapy.After twice maggot debridement,most necrotic muscle tissues of the wound were cleaned up,and eventually fresh granulation tissue grew and later the wound was covered and healed by 3 times of skin grafting.The result demonstrates that maggot therapy is safe and effective with no adverse complications except pain.

  1. Cartilage tissue engineering: towards a biomaterial-assisted mesenchymal stem cell therapy

    Science.gov (United States)

    Vinatier, Claire; Bouffi, Carine; Merceron, Christophe; Gordeladze, Jan; Brondello, Jean-Marc; Jorgensen, Christian; Weiss, Pierre; Guicheux, Jérôme; Noël, Danièle

    2009-01-01

    Injuries to articular cartilage are one of the most challenging issues of musculoskeletal medicine due to the poor intrinsic ability of this tissue for repair. Despite progress in orthopaedic surgery, the lack of efficient modalities of treatment for large chondral defects has prompted research on tissue engineering combining chondrogenic cells, scaffold materials and environmental factors. The aim of this review is to focus on the recent advances made in exploiting the potentials of cell therapy for cartilage engineering. These include: 1) defining the best cell candidates between chondrocytes or multipotent progenitor cells, such as multipotent mesenchymal stromal cells (MSC), in terms of readily available sources for isolation, expansion and repair potential; 2) engineering biocompatible and biodegradable natural or artificial matrix scaffolds as cell carriers, chondrogenic factors releasing factories and supports for defect filling, 3) identifying more specific growth factors and the appropriate scheme of application that will promote both chondrogenic differentiation and then maintain the differentiated phenotype overtime and 4) evaluating the optimal combinations that will answer to the functional demand placed upon cartilage tissue replacement in animal models and in clinics. Finally, some of the major obstacles generally encountered in cartilage engineering are discussed as well as future trends to overcome these limiting issues for clinical applications. PMID:19804369

  2. Influence of aryl hydrocarbon- (Ah) receptor and genotoxins on DNA repair gene expression and cell survival of mouse hepatoma cells

    International Nuclear Information System (INIS)

    The aryl hydrocarbon receptor (AhR) mediates toxicity of a variety of environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) and dioxins. However, the underlying mechanisms and genetic programmes regulated by AhR to cause adverse effects but also to counteract poisoning are still poorly understood. Here we analysed the effects of two AhR ligands, benzo[a]pyrene (B[a]P), a DNA damaging tumour initiator and promotor and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a pure tumour promoter, on cell survival and on nucleotide excision repair (NER) gene expression. NER deals with so called 'bulky' DNA adducts including those generated by enzymatically activated B[a]P. Therefore, the hypothesis that AhR may enhance NER gene expression to trigger DNA repair in the presence of genotoxic AhR ligands was tested. Furthermore, we investigated a potential cytoprotective effect of AhR activation by the non-genotoxic ligand TCDD against cell death induced by various genotoxins. Finally, the actions of genotoxins themselves on NER gene expression were studied. As a cell culture model we used mouse hepatoma cells (Hepa-c7) proficient for AhR and its partner protein ARNT as well as subclones deficient in AhR (Hepa-c12) or ARNT (Hepa-c4) to study involvement of AhR and ARNT in response to B[a]P and TCDD. Indeed, the mRNA levels of the two NER genes XP-C and DNA polymerase kappa were increased by B[a]P and TCDD, however, this was not accompanied by an increase in the amount of the respective proteins. Pretreatment of cells with TCDD did not reduce cytotoxicity induced by various genotoxins. Thus, in Hepa-c7 cells AhR has no major effects on the expression of these crucial NER proteins and does not prevent genotoxin-provoked cell death. As expected, the genotoxins B[a]P and cis-platin led to p53 accumulation and induction of its target p21. Interestingly, however, NER gene expression was not enhanced but rather decreased. As two NER genes, XP-C and DNA damage binding

  3. Repair, regenerative and supportive therapies of the annulus fibrosus: achievements and challenges

    OpenAIRE

    Bron, J.L.; Helder, M N; Meisel, H. J.; Royen, Van, Paul; Smit, T. H.

    2009-01-01

    Lumbar discectomy is a very effective therapy for neurological decompression in patients suffering from sciatica due to hernia nuclei pulposus. However, high recurrence rates and persisting post-operative low back pain in these patients require serious attention. In the past decade, tissue engineering strategies have been developed mainly targeted to the regeneration of the nucleus pulposus (NP) of the intervertebral disc. Accompanying techniques that deal with the damaged annulus fibrous are...

  4. Maggot therapy for repairing serious infective wound in a severely burned patient

    OpenAIRE

    WU Jun-cheng; LU Ren-rong; HUO, RAN; FU Hong-bin

    2012-01-01

    【Abstract】The larvae of musca domestica were put in use to discard the dead tissue of a case of severe burn. A total of 50 000 aseptic maggots were put onto the infective wound surface, and aseptic dressings overlaid the surface. Three days later, another 20 000 maggots were put onto the wound for the second therapy. After twice maggot debridement, most necrotic muscle tissues of the wound were cleaned up, and eventually fresh granulation tissue grew and later the woun...

  5. Toxicity DNA damage and inhibition of DNA repair synthesis in human melanoma cells by concentrated sunlight

    International Nuclear Information System (INIS)

    A water lens was used to focus solar radiation, giving an 8-fold concentration of the total spectrum and a cytocidal flux similar to that of laboratory UV sources. Survival curves for human melanoma cells were similar for sunlight and 254 nm UV. An xeroderma pigmentosum lymphoblastoid line was equally sensitive to both agents and human cell lines sensitive to ionizing radiation (lymphoblastoid lines), crosslinking agents or monofunctional alkylating agents (melanoma lines) had the same 254 nm UV and solar survival responses as appropriate control lines. Two melanoma sublines derived separately by 16 cycles of treatment with sunlight or 254 nm UV were crossresistant to both agents. In one melanoma cell line, DNA strand breaks and DNA protein crosslinking were induced in melanoma cells by sunlight but pyrimidine dimers and DNA interstrand crosslinking could not be detected. The solar fluence response of DNA repair synthesis was much less than that from equitoxic 254 nm UV, reaching a maximum near the D0 value and then declining; but semiconservative DNA synthesis remained high. These effects were not due to changes in thymidine pool sizes. Solar exposure did not have a major effect on 254 nm UV-induced repair synthesis. (author)

  6. RNF4 regulates DNA double-strand break repair in a cell cycle-dependent manner.

    Science.gov (United States)

    Kuo, Ching-Ying; Li, Xu; Stark, Jeremy M; Shih, Hsiu-Ming; Ann, David K

    2016-03-18

    Both RNF4 and KAP1 play critical roles in the response to DNA double-strand breaks (DSBs), but the functional interplay of RNF4 and KAP1 in regulating DNA damage response remains unclear. We have previously demonstrated the recruitment and degradation of KAP1 by RNF4 require the phosphorylation of Ser824 (pS824) and SUMOylation of KAP1. In this report, we show the retention of DSB-induced pS824-KAP1 foci and RNF4 abundance are inversely correlated as cell cycle progresses. Following irradiation, pS824-KAP1 foci predominantly appear in the cyclin A (-) cells, whereas RNF4 level is suppressed in the G0-/G1-phases and then accumulates during S-/G2-phases. Notably, 53BP1 foci, but not BRCA1 foci, co-exist with pS824-KAP1 foci. Depletion of KAP1 yields opposite effect on the dynamics of 53BP1 and BRCA1 loading, favoring homologous recombination repair. In addition, we identify p97 is present in the RNF4-KAP1 interacting complex and the inhibition of p97 renders MCF7 breast cancer cells relatively more sensitive to DNA damage. Collectively, these findings suggest that combined effect of dynamic recruitment of RNF4 to KAP1 regulates the relative occupancy of 53BP1 and BRCA1 at DSB sites to direct DSB repair in a cell cycle-dependent manner. PMID:26766492

  7. Schwann Cells Transplantation Promoted and the Repair of Brain Stem Injury in Rats

    Institute of Scientific and Technical Information of China (English)

    HONG WAN; YI-HUA AN; MEI-ZHEN SUN; YA-ZHUO ZHANG; ZHONG-CHENG WANG

    2003-01-01

    To explore the possibility of Schwann cells transplantation to promote the repair of injured brain stem reticular structure in rats. Methods Schwann cells originated from sciatic nerves of 1 to 2-day-old rats were expanded and labelled by BrdU in vitro, transplanted into rat brain stem reticular structure that was pre-injured by electric needle stimulus. Immunohistochemistry and myelin-staining were used to investigate the expression of BrdU, GAP-43 and new myelination respectively. Results BrdU positive cells could be identified for up to 8 months and their number increased by about 23%, which mainly migrated toward injured ipsilateral cortex. The GAP-43expression reached its peak in 1 month after transplantation and was significantly higher than that in the control group. New myelination could be seen in destructed brain stem areas. Conclusion The transplantation of Schwann cells can promote the restoration of injured brain stem reticular structure.

  8. Application of Nanoscaffolds in Mesenchymal Stem Cell-Based Therapy

    OpenAIRE

    Ghoraishizadeh, Saman; Ghorishizadeh, Afsoon; Ghoraishizadeh, Peyman; Daneshvar, Nasibeh; Boroojerdi, Mohadese Hashem

    2014-01-01

    Regenerative medicine is an alternative solution for organ transplantation. Stem cells and nanoscaffolds are two essential components in regenerative medicine. Mesenchymal stem cells (MSCs) are considered as primary adult stem cells with high proliferation capacity, wide differentiation potential, and immunosuppression properties which make them unique for regenerative medicine and cell therapy. Scaffolds are engineered nanofibers that provide suitable microenvironment for cell signalling whi...

  9. Tumor Cell Response to Synchrotron Microbeam Radiation Therapy Differs Markedly From Cells in Normal Tissues

    International Nuclear Information System (INIS)

    Purpose: High-dose synchrotron microbeam radiation therapy (MRT) can be effective at destroying tumors in animal models while causing very little damage to normal tissues. The aim of this study was to investigate the cellular processes behind this observation of potential clinical importance. Methods and Materials: MRT was performed using a lattice of 25 μm-wide, planar, polychromatic, kilovoltage X-ray microbeams, with 200-μm peak separation. Inoculated EMT-6.5 tumor and normal mouse skin tissues were harvested at defined intervals post-MRT. Immunohistochemical detection of γ-H2AX allowed precise localization of irradiated cells, which were also assessed for proliferation and apoptosis. Results: MRT significantly reduced tumor cell proliferation by 24 h post-irradiation (p = 0.002). An unexpected finding was that within 24 h of MRT, peak and valley irradiated zones were indistinguishable in tumors because of extensive cell migration between the zones. This was not seen in MRT-treated normal skin, which appeared to undergo a coordinated repair response. MRT elicited an increase in median survival times of EMT-6.5 and 67NR tumor-inoculated mice similar to that achieved with conventional radiotherapy, while causing markedly less normal tissue damage. Conclusions: This study provides evidence of a differential response at a cellular level between normal and tumor tissues after synchrotron MRT.

  10. Mesenchymal Stem Cells Enhance Nerve Regeneration in a Rat Sciatic Nerve Repair and Hindlimb Transplant Model

    Science.gov (United States)

    Cooney, Damon S.; Wimmers, Eric G.; Ibrahim, Zuhaib; Grahammer, Johanna; Christensen, Joani M.; Brat, Gabriel A.; Wu, Lehao W.; Sarhane, Karim A.; Lopez, Joseph; Wallner, Christoph; Furtmüller, Georg J.; Yuan, Nance; Pang, John; Sarkar, Kakali; Lee, W. P. Andrew; Brandacher, Gerald

    2016-01-01

    This study investigates the efficacy of local and intravenous mesenchymal stem cell (MSC) administration to augment neuroregeneration in both a sciatic nerve cut-and-repair and rat hindlimb transplant model. Bone marrow-derived MSCs were harvested and purified from Brown-Norway (BN) rats. Sciatic nerve transections and repairs were performed in three groups of Lewis (LEW) rats: negative controls (n = 4), local MSCs (epineural) injection (n = 4), and systemic MSCs (intravenous) injection (n = 4). Syngeneic (LEW-LEW) (n = 4) and allogeneic (BN-LEW) (n = 4) hindlimb transplants were performed and assessed for neuroregeneration after local or systemic MSC treatment. Rats undergoing sciatic nerve cut-and-repair and treated with either local or systemic injection of MSCs had significant improvement in the speed of recovery of compound muscle action potential amplitudes and axon counts when compared with negative controls. Similarly, rats undergoing allogeneic hindlimb transplants treated with local injection of MSCs exhibited significantly increased axon counts. Similarly, systemic MSC treatment resulted in improved nerve regeneration following allogeneic hindlimb transplants. Systemic administration had a more pronounced effect on electromotor recovery while local injection was more effective at increasing fiber counts, suggesting different targets of action. Local and systemic MSC injections significantly improve the pace and degree of nerve regeneration after nerve injury and hindlimb transplantation. PMID:27510321

  11. Tissue engineering and the use of stem/progenitor cells for airway epithelium repair

    Directory of Open Access Journals (Sweden)

    GM Roomans

    2010-06-01

    Full Text Available Stem/progenitor cells can be used to repair defects in the airway wall, resulting from e.g., tumors, trauma, tissue reactions following long-time intubations, or diseases that are associated with epithelial damage. Several potential sources of cells for airway epithelium have been identified. These can be divided into two groups. The first group consists of endogenous progenitor cells present in the respiratory tract. This group can be subdivided according to location into (a a ductal cell type in the submucosal glands of the proximal trachea, (b basal cells in the intercartilaginous zones of the lower trachea and bronchi, (c variant Clara cells (Clarav-cells in the bronchioles and (d at the junctions between the bronchioles and the alveolar ducts, and (e alveolar type II cells. This classification of progenitor cell niches is, however, controversial. The second group consists of exogenous stem cells derived from other tissues in the body. This second group can be subdivided into: (a embryonic stem (ES cells, induced pluripotent stem (iPS cells, or amniotic fluid stem cells, (b side-population cells from bone marrow or epithelial stem cells present in bone marrow or circulation and (c fat-derived mesenchymal cells. Airway epithelial cells can be co-cultured in a system that includes a basal lamina equivalent, extracellular factors from mesenchymal fibroblasts, and in an air-liquid interface system. Recently, spheroid-based culture systems have been developed. Several clinical applications have been suggested: cystic fibrosis, acute respiratory distress syndrome, chronic obstructive lung disease, pulmonary fibrosis, pulmonary edema, and pulmonary hypertension. Clinical applications so far are few, but include subglottic stenosis, tracheomalacia, bronchiomalacia, and emphysema.

  12. Effects of expanded bone marrow cells supported by stromal cells on hematopoietic repair in lethally irradiated mice

    International Nuclear Information System (INIS)

    Objective: To compare the effects of bone marrow cells expanded under different conditions on hematopoietic repair of radiation injury. Methods: In the liquid expanded cultural system with several cytokines and/or a bone marrow stromal cell layer, bone marrow mononuclear cells of mice were expanded for 5 days. Then, the expanded cells were transplanted to lethally irradiated mice via the caudal vein. The hematopoietic recovery of mice after transplantation was assessed by analysing the peripheral blood Hb,WBC, TBC and observing the survival states. Results: Ex vivo expansion of bone marrow mononuclear cells with combined use of cytokines under our cultural conditions can not improve the hematopoietic recovery of post-irradiated mice, but the expansion supported by bone marrow stromal cells can accelerate this process significantly

  13. MS Stem Cell Therapy Succeeds but Poses Risks

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_159285.html MS Stem Cell Therapy Succeeds But Poses Risks Toxic side effects ... HealthDay News) -- A treatment combining chemotherapy and a stem cell transplant could represent a major advance against aggressive ...

  14. MS Stem Cell Therapy Succeeds but Poses Risks

    Science.gov (United States)

    ... nih.gov/medlineplus/news/fullstory_159285.html MS Stem Cell Therapy Succeeds But Poses Risks Toxic side effects ... HealthDay News) -- A treatment combining chemotherapy and a stem cell transplant could represent a major advance against aggressive ...

  15. Repair and mutagenesis of herpes simplex virus in UV-irradiated monkey cells

    International Nuclear Information System (INIS)

    Mutagenic repair in mammalian cells was investigated by determining the mutagenesis of UV-irradiated or unirradiated herpes simplex virus in UV-irradiated CV-1 monkey kidney cells. These results were compared with the results for UV-enhanced virus reactivation (UVER) in the same experimental situation. High and low multiplicities of infection were used to determine the effects of multiplicity reactivation (MR). UVER and MR were readily demonstrable and were approximately equal in amount in an infectious center assay. For this study, a forward-mutation assay was developed to detect virus mutants resistant to iododeoxycytidine (ICdR), probably an indication of the mutant virus being defective at its thymidine kinase locus. ICdR-resistant mutants did not have a growth advantage over wild-type virus in irradiated or unirradiated cells. Thus, higher fractions of mutant virus indicated greater mutagenesis during virus repair and/or replication. The data showed that: (1) unirradiated virus was mutated in unirradiated cells, providing a background level of mutagenesis; (2) unirradiated virus was mutated about 40% more in irradiated cells, indicating that virus replication (DNA synthesis) became more mutagenic as a result of cell irradiation; (3) irradiated virus was mutated much more (about 6-fold) than unirradiated virus, even in unirradiated cells; (4) cell irradiation did not change the mutagenesis of irradiated virus except at high multiplicity of infection. High multiplicity of infection did not demonstrate UVER or MR alone to be either error-free or error-prone. When the two processes were present simultaneously, they were mutagenic. (orig.)

  16. Dynamic loading, matrix maintenance and cell injection therapy of human intervertebral discs cultured in a bioreactor.

    Science.gov (United States)

    Rosenzweig, D H; Gawri, R; Moir, J; Beckman, L; Eglin, D; Steffen, T; Roughley, P J; Ouellet, J A; Haglund, L

    2016-01-01

    Low back pain originating from intervertebral disc (IVD) degeneration affects the quality of life for millions of people, and it is a major contributor to global healthcare costs. Long-term culture of intact IVDs is necessary to develop ex vivo models of human IVD degeneration and repair, where the relationship between mechanobiology, disc matrix composition and metabolism can be better understood. A bioreactor was developed that facilitates culture of intact human IVDs in a controlled, dynamically loaded environment. Tissue integrity and cell viability was evaluated under 3 different loading conditions: low 0.1-0.3, medium 0.1-0.3 and high 0.1-1.2 MPa. Cell viability was maintained > 80 % throughout the disc at low and medium loads, whereas it dropped to approximately 70 % (NP) and 50 % (AF) under high loads. Although cell viability was affected at high loads, there was no evidence of sGAG loss, changes in newly synthesised collagen type II or chondroadherin fragmentation. Sulphated GAG content remained at a stable level of approximately 50 µg sGAG/mg tissue in all loading protocols. To evaluate the feasibility of tissue repair strategies with cell supplementation, human NP cells were transplanted into discs within a thermoreversible hyaluronan hydrogel. The discs were loaded under medium loads, and the injected cells remained largely localised to the NP region. This study demonstrates the feasibility of culturing human IVDs for 14 days under cyclic dynamic loading conditions. The system allows the determination a safe range-of-loading and presents a platform to evaluate cell therapies and help to elucidate the effect of load following cell-based therapies. PMID:26728497

  17. mTOR inhibition and levels of the DNA repair protein MGMT in T98G glioblastoma cells

    Science.gov (United States)

    2014-01-01

    Background Glioblastoma multiforme (GBM), the most common and most aggressive type of primary adult brain tumour, responds poorly to conventional treatment. Temozolomide (TMZ) chemotherapy remains the most commonly used treatment, despite a large proportion of tumours displaying TMZ resistance. 60% of GBM tumours have unmethylated MGMT promoter regions, resulting in an overexpression of the DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT), which is responsible for tumour resistance to TMZ chemotherapy. Tumours also often exhibit hyperactive PI3-kinase/mTOR signalling, which enables them to resynthesise proteins quickly. Since MGMT is a suicide protein that is degraded upon binding to and repairing TMZ-induced O6-methylguanine adducts, it has been hypothesized that inhibition of translation via the mTOR signalling pathway could generate a tumour-specific reduction in MGMT protein and increase TMZ sensitivity. Methods MGMT was monitored at the post-transcriptional, translational and protein levels, to determine what effect mTOR inhibition was having on MGMT protein expression in vitro. Results We show that inhibiting mTOR signalling is indeed associated with acute inhibition of protein synthesis. Western blots show that despite this, relative to loading control proteins, steady state levels of MGMT protein increased and MGMT mRNA was retained in heavy polysomes. Whilst TMZ treatment resulted in maintained MGMT protein levels, concomitant treatment of T98G cells with TMZ and KU0063794 resulted in increased MGMT protein levels without changes in total mRNA levels. Conclusions These in vitro data suggest that, counterintuitively, mTOR inhibition may not be a useful adjunct to TMZ therapy and that more investigation is needed before applying mTOR inhibitors in a clinical setting. PMID:24909675

  18. Differential regulation of intracellular factors mediating cell cycle, DNA repair and inflammation following exposure to silver nanoparticles in human cells

    Directory of Open Access Journals (Sweden)

    AshaRani PV

    2012-02-01

    Full Text Available Abstract Background Investigating the cellular and molecular signatures in eukaryotic cells following exposure to nanoparticles will further our understanding on the mechanisms mediating nanoparticle induced effects. This study illustrates the molecular effects of silver nanoparticles (Ag-np in normal human lung cells, IMR-90 and human brain cancer cells, U251 with emphasis on gene expression, induction of inflammatory mediators and the interaction of Ag-np with cytosolic proteins. Results We report that silver nanoparticles are capable of adsorbing cytosolic proteins on their surface that may influence the function of intracellular factors. Gene and protein expression profiles of Ag-np exposed cells revealed up regulation of many DNA damage response genes such as Gadd 45 in both the cell types and ATR in cancer cells. Moreover, down regulation of genes necessary for cell cycle progression (cyclin B and cyclin E and DNA damage response/repair (XRCC1 and 3, FEN1, RAD51C, RPA1 was observed in both the cell lines. Double strand DNA damage was observed in a dose dependant manner as evidenced in γH2AX foci assay. There was a down regulation of p53 and PCNA in treated cells. Cancer cells in particular showed a concentration dependant increase in phosphorylated p53 accompanied by the cleavage of caspase 3 and PARP. Our results demonstrate the involvement of NFκB and MAP kinase pathway in response to Ag-np exposure. Up regulation of pro-inflammatory cytokines such as interleukins (IL-8, IL-6, macrophage colony stimulating factor, macrophage inflammatory protein in fibroblasts following Ag-np exposure were also observed. Conclusion In summary, Ag-np can modulate gene expression and protein functions in IMR-90 cells and U251 cells, leading to defective DNA repair, proliferation arrest and inflammatory response. The observed changes could also be due to its capability to adsorb cytosolic proteins on its surface.

  19. Targeting Cancer Stem Cells with Nanoparticle-Enabled Therapies

    OpenAIRE

    Burke, Andrew R.; Singh, Ravi N.; Carroll, David L.; Torti, Frank M.; Torti, Suzy V.

    2012-01-01

    Emerging evidence suggests that multiple tumor types are sustained by a small population of transformed stem-like cells that have the ability to both self-renew and give rise to non-tumorigenic daughter cells that constitute the bulk of a tumor. These cells, which generally constitute a minority of the overall cancer cell population, are highly resistant to conventional therapies and persist following treatment, leading to disease relapse and the formation of distant metastases. Therapies tha...

  20. Relationship of DNA repair processes to mutagenesis and carcinogenesis in mammalian cells. Three-year report, February 1, 1981-September 30, 1983

    International Nuclear Information System (INIS)

    Mutant strains were selected which are deficient in various DNA repair pathways and these were studied with regard to (1) the nature of the defect in repair, and (2) the mutability and transformability of the defective cells by various agents as compared to the wild type parental cells. Lightly mutagenized wild-type cells were infected with irradiated herpes simplex virus (HSV). Cells which repair HSV are lysed so the surviving population is enriched in repair-deficient cells. Six strains which survived two rounds of infection were characterized with respect to their radiosensitivity