Cardiac Restoration Stemming From the Placenta Tree: Insights From Fetal and Perinatal Cell Biology

Directory of Open Access Journals (Sweden)

Sveva Bollini

2018-04-01

Full Text Available Efficient cardiac repair and ultimate regeneration still represents one of the main challenges of modern medicine. Indeed, cardiovascular disease can derive from independent conditions upsetting heart structure and performance: myocardial ischemia and infarction (MI, pharmacological cardiotoxicity, and congenital heart defects, just to name a few. All these disorders have profound consequences on cardiac tissue, inducing the onset of heart failure over time. Since the cure is currently represented by heart transplantation, which is extremely difficult due to the shortage of donors, much effort is being dedicated to developing innovative therapeutic strategies based on stem cell exploitation. Among the broad scenario of stem/progenitor cell subpopulations, fetal and perinatal sources, namely amniotic fluid and term placenta, have gained interest due to their peculiar regenerative capacity, high self-renewal capability, and ease of collection from clinical waste material. In this review, we will provide the state-of-the-art on fetal perinatal stem cells for cardiac repair and regeneration. We will discuss different pathological conditions and the main therapeutic strategies proposed, including cell transplantation, putative paracrine therapy, reprogramming, and tissue engineering approaches.

How Can Nanotechnology Help to Repair the Body? Advances in Cardiac, Skin, Bone, Cartilage and Nerve Tissue Regeneration

Directory of Open Access Journals (Sweden)

Juan Antonio Marchal

2013-03-01

Full Text Available Nanotechnologists have become involved in regenerative medicine via creation of biomaterials and nanostructures with potential clinical implications. Their aim is to develop systems that can mimic, reinforce or even create in vivo tissue repair strategies. In fact, in the last decade, important advances in the field of tissue engineering, cell therapy and cell delivery have already been achieved. In this review, we will delve into the latest research advances and discuss whether cell and/or tissue repair devices are a possibility. Focusing on the application of nanotechnology in tissue engineering research, this review highlights recent advances in the application of nano-engineered scaffolds designed to replace or restore the followed tissues: (i skin; (ii cartilage; (iii bone; (iv nerve; and (v cardiac.

DNA repair , cell repair and radiosensitivity

International Nuclear Information System (INIS)

Zhestyanikov, V.D.

1983-01-01

Data obtained in laboratory of radiation cytology and literature data testifying to a considerable role of DNA repair in cell sensitivity to radiation and chemical DNA-tropic agents have been considered. Data pointing to the probability of contribution of inducible repair of DNA into plant cells sensitivity to X-rays are obtained. Certain violations of DNA repair do not result in the increase of radiosensitivity. It is assumed that in the cases unknown mechanisms of DNA repair operate

PROPOSED CARDIAC STEM CELLS DERIVED FROM “CARDIOSPHERES” LACK CARDIOMYOGENIC POTENTIAL

DEFF Research Database (Denmark)

Andersen, Ditte Caroline

   Recent studies have reported that clinical relevant numbers of cardiac stem cells (CSCs) with cardiomyogenic potential can be obtained from small heart tissue biopsies, by an intrinsic ability of CSCs to form beating cardiospheres (CSs) during ex vivo culture. Such data have provided optimism...... that injuried heart tissue may be repaired by stem cell therapy using autologous CS derived cells, and pre-clinical studies have already been described in literature.    Herein, we established CSs from neonatal rats, and by immunofluorescence, qRT-PCR, and microscopic examination we demonstrated...... to form CSs by themselves. Phenotypically, CS cells largely resembled fibroblasts, and they lacked cardiomyogenic as well as endothelial differentiation potential.    Our data imply that at least the murine cardiosphere model seems unsuitable for enrichment of cardiac stem cells with cardiomyogenic...

8-Oxoguanine DNA glycosylase 1 (ogg1) maintains the function of cardiac progenitor cells during heart formation in zebrafish

Energy Technology Data Exchange (ETDEWEB)

Yan, Lifeng [State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029 (China); Zhou, Yong [Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China); Yu, Shanhe [Shanghai Institute of Hematology, RuiJin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025 (China); Ji, Guixiang [Nanjing Institute of Environmental Sciences/Key Laboratory of Pesticide Environmental Assessment and Pollution Control, Ministry of Environmental Protection, Nanjing 210042 (China); Wang, Lei [Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao Tong University School of Medicine, Shanghai 200025 (China); Liu, Wei [State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029 (China); Gu, Aihua, E-mail: aihuagu@njmu.edu.cn [State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 210029 (China)

2013-11-15

Genomic damage may devastate the potential of progenitor cells and consequently impair early organogenesis. We found that ogg1, a key enzyme initiating the base-excision repair, was enriched in the embryonic heart in zebrafish. So far, little is known about DNA repair in cardiogenesis. Here, we addressed the critical role of ogg1 in cardiogenesis for the first time. ogg1 mainly expressed in the anterior lateral plate mesoderm (ALPM), the primary heart tube, and subsequently the embryonic myocardium by in situ hybridisation. Loss of ogg1 resulted in severe cardiac morphogenesis and functional abnormalities, including the short heart length, arrhythmia, decreased cardiomyocytes and nkx2.5{sup +} cardiac progenitor cells. Moreover, the increased apoptosis and repressed proliferation of progenitor cells caused by ogg1 deficiency might contribute to the heart phenotype. The microarray analysis showed that the expression of genes involved in embryonic heart tube morphogenesis and heart structure were significantly changed due to the lack of ogg1. Among those, foxh1 is an important partner of ogg1 in the cardiac development in response to DNA damage. Our work demonstrates the requirement of ogg1 in cardiac progenitors and heart development in zebrafish. These findings may be helpful for understanding the aetiology of congenital cardiac deficits. - Highlights: • A key DNA repair enzyme ogg1 is expressed in the embryonic heart in zebrafish. • We found that ogg1 is essential for normal cardiac morphogenesis in zebrafish. • The production of embryonic cardiomyocytes requires appropriate ogg1 expression. • Ogg1 critically regulated proliferation of cardiac progenitor cells in zebrafish. • foxh1 is a partner of ogg1 in the cardiac development in response to DNA damage.

Electrical Stimulation Promotes Cardiac Differentiation of Human Induced Pluripotent Stem Cells

Directory of Open Access Journals (Sweden)

Damián Hernández

2016-01-01

Full Text Available Background. Human induced pluripotent stem cells (iPSCs are an attractive source of cardiomyocytes for cardiac repair and regeneration. In this study, we aim to determine whether acute electrical stimulation of human iPSCs can promote their differentiation to cardiomyocytes. Methods. Human iPSCs were differentiated to cardiac cells by forming embryoid bodies (EBs for 5 days. EBs were then subjected to brief electrical stimulation and plated down for 14 days. Results. In iPS(Foreskin-2 cell line, brief electrical stimulation at 65 mV/mm or 200 mV/mm for 5 min significantly increased the percentage of beating EBs present by day 14 after plating. Acute electrical stimulation also significantly increased the cardiac gene expression of ACTC1, TNNT2, MYH7, and MYL7. However, the cardiogenic effect of electrical stimulation was not reproducible in another iPS cell line, CERA007c6. Beating EBs from control and electrically stimulated groups expressed various cardiac-specific transcription factors and contractile muscle markers. Beating EBs were also shown to cycle calcium and were responsive to the chronotropic agents, isoproterenol and carbamylcholine, in a concentration-dependent manner. Conclusions. Our results demonstrate that brief electrical stimulation can promote cardiac differentiation of human iPS cells. The cardiogenic effect of brief electrical stimulation is dependent on the cell line used.

GRAF1 deficiency blunts sarcolemmal injury repair and exacerbates cardiac and skeletal muscle pathology in dystrophin-deficient mice.

Science.gov (United States)

Lenhart, Kaitlin C; O'Neill, Thomas J; Cheng, Zhaokang; Dee, Rachel; Demonbreun, Alexis R; Li, Jianbin; Xiao, Xiao; McNally, Elizabeth M; Mack, Christopher P; Taylor, Joan M

2015-01-01

The plasma membranes of striated muscle cells are particularly susceptible to rupture as they endure significant mechanical stress and strain during muscle contraction, and studies have shown that defects in membrane repair can contribute to the progression of muscular dystrophy. The synaptotagmin-related protein, dysferlin, has been implicated in mediating rapid membrane repair through its ability to direct intracellular vesicles to sites of membrane injury. However, further work is required to identify the precise molecular mechanisms that govern dysferlin targeting and membrane repair. We previously showed that the bin-amphiphysin-Rvs (BAR)-pleckstrin homology (PH) domain containing Rho-GAP GTPase regulator associated with focal adhesion kinase-1 (GRAF1) was dynamically recruited to the tips of fusing myoblasts wherein it promoted membrane merging by facilitating ferlin-dependent capturing of intracellular vesicles. Because acute membrane repair responses involve similar vesicle trafficking complexes/events and because our prior studies in GRAF1-deficient tadpoles revealed a putative role for GRAF1 in maintaining muscle membrane integrity, we postulated that GRAF1 might also play an important role in facilitating dysferlin-dependent plasma membrane repair. We used an in vitro laser-injury model to test whether GRAF1 was necessary for efficient muscle membrane repair. We also generated dystrophin/GRAF1 doubledeficient mice by breeding mdx mice with GRAF1 hypomorphic mice. Evans blue dye uptake and extensive morphometric analyses were used to assess sarcolemmal integrity and related pathologies in cardiac and skeletal muscles isolated from these mice. Herein, we show that GRAF1 is dynamically recruited to damaged skeletal and cardiac muscle plasma membranes and that GRAF1-depleted muscle cells have reduced membrane healing abilities. Moreover, we show that dystrophin depletion exacerbated muscle damage in GRAF1-deficient mice and that mice with dystrophin/GRAF1

Wnt/β-Catenin Signaling during Cardiac Development and Repair

Directory of Open Access Journals (Sweden)

Jan W. Buikema

2014-05-01

Full Text Available Active Wnt/β-catenin signaling is essential for proper cardiac specification, progenitor expansion and myocardial growth. During development, the mass of the embryonic heart increases multiple times to achieve the dimensions of adult ventricular chambers. Cell division in the embryonic heart is fairly present, whereas cell turnover in the adult myocardium is extremely low. Understanding of embryonic cardiomyocyte cell-replication, therefore, could improve strategies for cardiac regenerative therapeutics. Here, we review which role Wnt signaling plays in cardiac development and highlight a selection of attempts that have been made to modulate Wnt signaling after cardiac ischemic injury to improve cardiac function and reduce infarct size.

Cell tracking in cardiac repair: What to image and how to image

NARCIS (Netherlands)

A. Ruggiero (Alessandro); D.L.J. Thorek (Daniel L.J.); J. Guenoun (Jamal); G.P. Krestin (Gabriel); M.R. Bernsen (Monique)

2012-01-01

textabstractStem cell therapies hold the great promise and interest for cardiac regeneration among scientists, clinicians and patients. However, advancement and distillation of a standard treatment regimen are not yet finalised. Into this breach step recent developments in the imaging biosciences.

Cell-based therapies for cardiac repair : a meeting report on scientific observations and European regulatory viewpoints

NARCIS (Netherlands)

Schüssler-Lenz, Martina; Beuneu, Claire; Menezes-Ferreira, Margarida; Jekerle, Veronika; Bartunek, Jozef; Chamuleau, Steven; Celis, Patrick; Doevendans, Pieter; O'Donovan, Maura; Hill, Jonathan; Hystad, Marit; Jovinge, Stefan; Kyselovič, Ján; Lipnik-Stangelj, Metoda; Maciulaitis, Romaldas; Prasad, Krishna; Samuel, Anthony; Tenhunen, Olli; Tonn, Torsten; Rosano, Giuseppe; Zeiher, Andreas; Salmikangas, Paula

In the past decade, novel cell-based products have been studied in patients with acute and chronic cardiac disease to assess whether these therapies are efficacious in improving heart function and preventing the development of end-stage heart failure. Cardiac indications studied include acute

Case Report: Cardiac Rehabilitation in a Patient with MVR & AVR & Tricuspid Valve Repair

Directory of Open Access Journals (Sweden)

Babak Gousheh

2003-01-01

Full Text Available Patient is a 24 year .old male with valvular heart disease, severe mitral & aortic & tricuspid valve stenosis and regurgitation. After MVR & AVR & tricuspid surgical repair, he has undergone cardiac rehabilitation for 8 weeks (24 sittings. After completion of a cardiac rehabilitation, review of cardiovascular tests showed obvious improvement in the functional capacity, blood pressure and heart rate. Physically and mentally patient feels very comfortable and hopeful of a good healthy life.

Surface-modified polymers for cardiac tissue engineering.

Science.gov (United States)

Moorthi, Ambigapathi; Tyan, Yu-Chang; Chung, Tze-Wen

2017-09-26

Cardiovascular disease (CVD), leading to myocardial infarction and heart failure, is one of the major causes of death worldwide. The physiological system cannot significantly regenerate the capabilities of a damaged heart. The current treatment involves pharmacological and surgical interventions; however, less invasive and more cost-effective approaches are sought. Such new approaches are developed to induce tissue regeneration following injury. Hence, regenerative medicine plays a key role in treating CVD. Recently, the extrinsic stimulation of cardiac regeneration has involved the use of potential polymers to stimulate stem cells toward the differentiation of cardiomyocytes as a new therapeutic intervention in cardiac tissue engineering (CTE). The therapeutic potentiality of natural or synthetic polymers and cell surface interactive factors/polymer surface modifications for cardiac repair has been demonstrated in vitro and in vivo. This review will discuss the recent advances in CTE using polymers and cell surface interactive factors that interact strongly with stem cells to trigger the molecular aspects of the differentiation or formulation of cardiomyocytes for the functional repair of heart injuries or cardiac defects.

A review of the use of cardiac computed tomography for evaluating the mitral valve before and after mitral valve repair

Energy Technology Data Exchange (ETDEWEB)

Kim, Jong Hun; Choi, Jong Bum [Dept. of Thoracic and Cardiovascular Surgery, Chonbuk National University Medical School, Research Institute of Clinical Medicine of Chonbuk National University, Biomedical Research Institute of Chonbuk National University Hospital, Jeonju (Korea, Republic of); Kim, Eun Young; Jin, Gong Yong [Dept. of Radiology, Radiology, Research Institute of Clinical Medicine of Chonbuk National University, Biomedical Research Institute of Chonbuk National University Hospital, Institute for Medical Sciences of Chonbuk National University Medical School, Jeonju (Korea, Republic of)

2017-09-15

The role of cardiac computed tomography (CT) for evaluating the mitral valve (MV) has been limited since echocardiography is the main method of evaluation. However, recent advances in cardiac CT have enable detailed evaluation of the anatomy and geometry of the MV. We describe assessments of the anatomy and coaptation geometric parameters of normal MVs, and also review repair of diseased/damaged MV. We also discuss pre- and post-surgical imaging of MV pathology using cardiac CT and various CT images. We found that cardiac CT could be used as an alternative imaging modality to echocardiography for pre-operative MV evaluation and to predict clinical outcomes following repair.

A review of the use of cardiac computed tomography for evaluating the mitral valve before and after mitral valve repair

International Nuclear Information System (INIS)

Kim, Jong Hun; Choi, Jong Bum; Kim, Eun Young; Jin, Gong Yong

2017-01-01

The role of cardiac computed tomography (CT) for evaluating the mitral valve (MV) has been limited since echocardiography is the main method of evaluation. However, recent advances in cardiac CT have enable detailed evaluation of the anatomy and geometry of the MV. We describe assessments of the anatomy and coaptation geometric parameters of normal MVs, and also review repair of diseased/damaged MV. We also discuss pre- and post-surgical imaging of MV pathology using cardiac CT and various CT images. We found that cardiac CT could be used as an alternative imaging modality to echocardiography for pre-operative MV evaluation and to predict clinical outcomes following repair

Engineering Cardiac Muscle Tissue: A Maturating Field of Research.

Science.gov (United States)

Weinberger, Florian; Mannhardt, Ingra; Eschenhagen, Thomas

2017-04-28

Twenty years after the initial description of a tissue engineered construct, 3-dimensional human cardiac tissues of different kinds are now generated routinely in many laboratories. Advances in stem cell biology and engineering allow for the generation of constructs that come close to recapitulating the complex structure of heart muscle and might, therefore, be amenable to industrial (eg, drug screening) and clinical (eg, cardiac repair) applications. Whether the more physiological structure of 3-dimensional constructs provides a relevant advantage over standard 2-dimensional cell culture has yet to be shown in head-to-head-comparisons. The present article gives an overview on current strategies of cardiac tissue engineering with a focus on different hydrogel methods and discusses perspectives and challenges for necessary steps toward the real-life application of cardiac tissue engineering for disease modeling, drug development, and cardiac repair. © 2017 American Heart Association, Inc.

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.

Cardiac Bmi1(+) cells contribute to myocardial renewal in the murine adult heart.

Science.gov (United States)

Valiente-Alandi, Iñigo; Albo-Castellanos, Carmen; Herrero, Diego; Arza, Elvira; Garcia-Gomez, Maria; Segovia, José C; Capecchi, Mario; Bernad, Antonio

2015-10-26

The mammalian adult heart maintains a continuous, low cardiomyocyte turnover rate throughout life. Although many cardiac stem cell populations have been studied, the natural source for homeostatic repair has not yet been defined. The Polycomb protein BMI1 is the most representative marker of mouse adult stem cell systems. We have evaluated the relevance and role of cardiac Bmi1 (+) cells in cardiac physiological homeostasis. Bmi1 (CreER/+);Rosa26 (YFP/+) (Bmi1-YFP) mice were used for lineage tracing strategy. After tamoxifen (TM) induction, yellow fluorescent protein (YFP) is expressed under the control of Rosa26 regulatory sequences in Bmi1 (+) cells. These cells and their progeny were tracked by FACS, immunofluorescence and RT-qPCR techniques from 5 days to 1 year. FACS analysis of non-cardiomyocyte compartment from TM-induced Bmi1-YFP mice showed a Bmi1 (+)-expressing cardiac progenitor cell (Bmi1-CPC: B-CPC) population, SCA-1 antigen-positive (95.9 ± 0.4 %) that expresses some stemness-associated genes. B-CPC were also able to differentiate in vitro to the three main cardiac lineages. Pulse-chase analysis showed that B-CPC remained quite stable for extended periods (up to 1 year), which suggests that this Bmi1 (+) population contains cardiac progenitors with substantial self-maintenance potential. Specific immunostaining of Bmi1-YFP hearts serial sections 5 days post-TM induction indicated broad distribution of B-CPC, which were detected in variably sized clusters, although no YFP(+) cardiomyocytes (CM) were detected at this time. Between 2 to 12 months after TM induction, YFP(+) CM were clearly identified (3 ± 0.6 % to 6.7 ± 1.3 %) by immunohistochemistry of serial sections and by flow cytometry of total freshly isolated CM. B-CPC also contributed to endothelial and smooth muscle (SM) lineages in vivo. High Bmi1 expression identifies a non-cardiomyocyte resident cardiac population (B-CPC) that contributes to the main lineages of the heart in

Nucleotide excision repair in differentiated cells

Energy Technology Data Exchange (ETDEWEB)

Wees, Caroline van der [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Department of Cardiology, Leiden University Medical Center, Leiden (Netherlands); Jansen, Jacob [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Vrieling, Harry [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Laarse, Arnoud van der [Department of Cardiology, Leiden University Medical Center, Leiden (Netherlands); Zeeland, Albert van [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Mullenders, Leon [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands)]. E-mail: l.mullenders@lumc.nl

2007-01-03

Nucleotide excision repair (NER) is the principal pathway for the removal of a wide range of DNA helix-distorting lesions and operates via two NER subpathways, i.e. global genome repair (GGR) and transcription-coupled repair (TCR). Although detailed information is available on expression and efficiency of NER in established mammalian cell lines, little is known about the expression of NER pathways in (terminally) differentiated cells. The majority of studies in differentiated cells have focused on repair of UV-induced cyclobutane pyrimidine dimers (CPD) and 6-4-photoproducts (6-4PP) because of the high frequency of photolesions at low level of toxicity and availability of sensitive technologies to determine photolesions in defined regions of the genome. The picture that emerges from these studies is blurred and rather complex. Fibroblasts and terminally differentiated myocytes of the rat heart display equally efficient GGR of 6-4PP but poor repair of CPD due to the absence of p48 expression. This repair phenotype is clearly different from human terminal differentiated neurons. Furthermore, both cell types were found to carry out TCR of CPD, thus mimicking the repair phenotype of established rodent cell lines. In contrast, in intact rat spermatogenic cells repair was very inefficient at the genome overall level and in transcriptionally active genes indicating that GGR and TCR are non-functional. Also, non-differentiated mouse embryonic stem (ES) cells exhibit low levels of NER after UV irradiation. However, the mechanisms that lead to low NER activity are clearly different: in differentiated spermatogenic cells differences in chromatin compaction and sequestering of NER proteins may underlie the lack of NER activity in pre-meiotic cells, whereas in non-differentiated ES cells NER is impaired by a strong apoptotic response.

Functional cardiomyocytes derived from Isl1 cardiac progenitors via Bmp4 stimulation.

Directory of Open Access Journals (Sweden)

Esra Cagavi

Full Text Available As heart failure due to myocardial infarction remains a leading cause of morbidity worldwide, cell-based cardiac regenerative therapy using cardiac progenitor cells (CPCs could provide a potential treatment for the repair of injured myocardium. As adult CPCs may have limitations regarding tissue accessibility and proliferative ability, CPCs derived from embryonic stem cells (ESCs could serve as an unlimited source of cells with high proliferative ability. As one of the CPCs that can be derived from embryonic stem cells, Isl1 expressing cardiac progenitor cells (Isl1-CPCs may serve as a valuable source of cells for cardiac repair due to their high cardiac differentiation potential and authentic cardiac origin. In order to generate an unlimited number of Isl1-CPCs, we used a previously established an ESC line that allows for isolation of Isl1-CPCs by green fluorescent protein (GFP expression that is directed by the mef2c gene, specifically expressed in the Isl1 domain of the anterior heart field. To improve the efficiency of cardiac differentiation of Isl1-CPCs, we studied the role of Bmp4 in cardiogenesis of Isl1-CPCs. We show an inductive role of Bmp directly on cardiac progenitors and its enhancement on early cardiac differentiation of CPCs. Upon induction of Bmp4 to Isl1-CPCs during differentiation, the cTnT+ cardiomyocyte population was enhanced 2.8±0.4 fold for Bmp4 treated CPC cultures compared to that detected for vehicle treated cultures. Both Bmp4 treated and untreated cardiomyocytes exhibit proper electrophysiological and calcium signaling properties. In addition, we observed a significant increase in Tbx5 and Tbx20 expression in differentiation cultures treated with Bmp4 compared to the untreated control, suggesting a link between Bmp4 and Tbx genes which may contribute to the enhanced cardiac differentiation in Bmp4 treated cultures. Collectively these findings suggest a cardiomyogenic role for Bmp4 directly on a pure population of

Human cardiac stem cells exhibit mesenchymal features and are maintained through Akt/GSK-3β signaling

International Nuclear Information System (INIS)

Tateishi, Kento; Ashihara, Eishi; Honsho, Shoken; Takehara, Naofumi; Nomura, Tetsuya; Takahashi, Tomosaburo; Ueyama, Tomomi; Yamagishi, Masaaki; Yaku, Hitoshi; Matsubara, Hiroaki; Oh, Hidemasa

2007-01-01

Recent evidence suggested that human cardiac stem cells (hCSCs) may have the clinical application for cardiac repair; however, their characteristics and the regulatory mechanisms of their growth have not been fully investigated. Here, we show the novel property of hCSCs with respect to their origin and tissue distribution in human heart, and demonstrate the signaling pathway that regulates their growth and survival. Telomerase-active hCSCs were predominantly present in the right atrium and outflow tract of the heart (infant > adult) and had a mesenchymal cell-like phenotype. These hCSCs expressed the embryonic stem cell markers and differentiated into cardiomyocytes to support cardiac function when transplanted them into ischemic myocardium. Inhibition of Akt pathway impaired the hCSC proliferation and induced apoptosis, whereas inhibition of glycogen synthase kinase-3 (GSK-3) enhanced their growth and survival. We conclude that hCSCs exhibit mesenchymal features and that Akt/GSK-3β may be crucial modulators for hCSC maintenance in human heart

DNA repair in human cells

International Nuclear Information System (INIS)

Regan, J.D.; Carrier, W.L.; Kusano, I.; Furuno-Fukushi, I.; Dunn, W.C. Jr.; Francis, A.A.; Lee, W.H.

1982-01-01

Our primary objective is to elucidate the molecular events in human cells when cellular macromolecules such as DNA are damaged by radiation or chemical agents. We study and characterize (i) the sequence of DNA repair events, (ii) the various modalities of repair, (iii) the genetic inhibition of repair due to mutation, (iv) the physiological inhibition of repair due to mutation, (v) the physiological inhibition of repair due to biochemical inhibitors, and (vi) the genetic basis of repair. Our ultimate goals are to (i) isolate and analyze the repair component of the mutagenic and/or carcinogenic event in human cells, and (ii) elucidate the magnitude and significance of this repair component as it impinges on the practical problems of human irradiation or exposure to actual or potential chemical mutagens and carcinogens. The significance of these studies lies in (i) the ubiquitousness of repair (most organisms, including man, have several complex repair systems), (ii) the belief that mutagenic and carcinogenic events may arise only from residual (nonrepaired) lesions or that error-prone repair systems may be the major induction mechanisms of the mutagenic or carcinogenic event, and (iii) the clear association of repair defects and highly carcinogenic disease states in man [xeroderma pigmentosum (XP)

Cell therapy attenuates cardiac dysfunction post myocardial infarction: effect of timing, routes of injection and a fibrin scaffold.

Directory of Open Access Journals (Sweden)

Juliana S Nakamuta

Full Text Available BACKGROUND: Cell therapy approaches for biologic cardiac repair hold great promises, although basic fundamental issues remain poorly understood. In the present study we examined the effects of timing and routes of administration of bone marrow cells (BMC post-myocardial infarction (MI and the efficacy of an injectable biopolymer scaffold to improve cardiac cell retention and function. METHODOLOGY/PRINCIPAL FINDINGS: (99mTc-labeled BMC (6 x 10(6 cells were injected by 4 different routes in adult rats: intravenous (IV, left ventricular cavity (LV, left ventricular cavity with temporal aorta occlusion (LV(+ to mimic coronary injection, and intramyocardial (IM. The injections were performed 1, 2, 3, or 7 days post-MI and cell retention was estimated by gamma-emission counting of the organs excised 24 hs after cell injection. IM injection improved cell retention and attenuated cardiac dysfunction, whereas IV, LV or LV* routes were somewhat inefficient (<1%. Cardiac BMC retention was not influenced by timing except for the IM injection that showed greater cell retention at 7 (16% vs. 1, 2 or 3 (average of 7% days post-MI. Cardiac cell retention was further improved by an injectable fibrin scaffold at day 3 post-MI (17 vs. 7%, even though morphometric and function parameters evaluated 4 weeks later displayed similar improvements. CONCLUSIONS/SIGNIFICANCE: These results show that cells injected post-MI display comparable tissue distribution profile regardless of the route of injection and that there is no time effect for cardiac cell accumulation for injections performed 1 to 3 days post-MI. As expected the IM injection is the most efficient for cardiac cell retention, it can be further improved by co-injection with a fibrin scaffold and it significantly attenuates cardiac dysfunction evaluated 4 weeks post myocardial infarction. These pharmacokinetic data obtained under similar experimental conditions are essential for further development of these

DNA replication and repair in Tilapia cells

International Nuclear Information System (INIS)

Yew, F.H.; Chang, L.M.

1984-01-01

The effect of ultraviolet radiation on a cell line established from the warm water fish Tilapia has been assessed by measuring the rate of DNA synthesis, excision repair, post-replication repair and cell survival. The cells tolerate ultraviolet radiation better than mammalian cells with respect to DNA synthesis, post-replication repair and cell survival. They are also efficient in excision repair, which in other fish cell lines has been found to be at a low level or absent. Their response to the inhibitors hydroxyurea and 1-β-D-arabinofuranosylcytosine is less sensitive than that of other cell lines, yet the cells seem to have very small pools of DNA precursor. (author)

Transfer of Chinese hamster DNA repair gene(s) into repair-deficient human cells (Xeroderma pigmentosum)

International Nuclear Information System (INIS)

Karentz, D.; Cleaver, J.E.

1985-01-01

Transfer of repair genes by DNA transfection into repair-deficient Xeroderma pigmentosum (XP) cells has thus far been unsuccessful, presenting an obstacle to cloning XP genes. The authors chose an indirect route to transfer repair genes in chromosome fragments. DNA repair-competent (UV resistant) hybrid cell lines were established by PEG-mediated fusions of DNA repair-deficient (UV sensitive) human fibroblasts (XP12RO) with wild type Chinese hamster (CHO) cells (AA8). CHO cells were exposed to 5 Krad X-rays prior to fusions, predisposing hybrid cells to lose CHO chromosome fragments preferentially. Repair-competent hybrids were selected by periodic exposures to UV light. Secondary and tertiary hybrid cell lines were developed by fusion of X-irradiated hybrids to XP12RO. The hybrid cell lines exhibit resistance to UV that is comparable to that of CHO cells and they are proficient at repair replication after UV exposure. Whole cell DNA-DNA hybridizations indicate that the hybrids have greater homology to CHO DNA than is evident between XP12RO and CHO. These observations indicate that CHO DNA sequences which can function in repair of UV-damaged DNA in human cells have been transferred into the genome of the repair-deficient XP12RO cells

Cardiac magnetic resonance markers of progressive RV dilation and dysfunction after tetralogy of Fallot repair

NARCIS (Netherlands)

Wald, Rachel M.; Valente, Anne Marie; Gauvreau, Kimberlee; Babu-Narayan, Sonya V.; Assenza, Gabriele Egidy; Schreier, Jenna; Gatzoulis, Michael A.; Kilner, Philip J.; Koyak, Zeliha; Mulder, Barbara; Powell, Andrew J.; Geva, Tal

2015-01-01

Patients with repaired tetralogy of Fallot (TOF) are followed serially by cardiac magnetic resonance (CMR) for surveillance of RV dilation and dysfunction. We sought to define the prevalence of progressive RV disease and the optimal time interval between CMR evaluations. Candidates were selected

Mesenchymal Stem Cells in Cardiology

Science.gov (United States)

White, Ian A.; Sanina, Cristina; Balkan, Wayne; Hare, Joshua M.

2017-01-01

Cardiovascular disease (CVD) accounts for more deaths globally than any other single disease. There are on average 1.5 million episodes of myocardial infarction (heart attack) each year in the United States alone with roughly one third resulting in death. There is therefore a major need for developing new and effective strategies to promote cardiac repair. Intramyocardial transplantation of mesenchymal stem cells (MSCs) has emerged as a leading contender in the pursuit of clinical intervention and therapy. MSCs are potent mediators of cardiac repair and are therefore an attractive tool in the development of pre-clinical and clinical trials. MSCs are capable of secreting a large array of soluble factors, which have had demonstrated effects on pathogenic cardiac remolding, fibrosis, immune activation and cardiac stem cell proliferation within the damaged heart. MSCs are also capable of differentiation into cardiomyocytes, endothelial cells and vascular smooth muscle cells, although the relative contribution of trilineage differentiation and paracrine effectors on cardiac repair remains the subject of active investigation. PMID:27236666

Repair-misrepair model of cell survival

International Nuclear Information System (INIS)

Tobias, C.A.; Blakely, E.A.; Ngo, F.Q.H.

1980-01-01

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

Repair in Ehrlich ascites tumor cells

International Nuclear Information System (INIS)

Wanna-Nakamura, S.S.

1981-01-01

Unscheduled DNA synthesis (UDS), an indicator of excision repair, was induced in freshly drawn Ehrlich ascites tumor cells (EAT), using ionizing radiation, far ultraviolet light (254 nm) or near uv light (365 nm) in combination with 8-methoxypsoralen. UDS was scored by grain counts in autoradiographs following the incorporation of tritium-labelled thymidine. The amount of UDS after each of these agents was expressed in terms of two parameters, viz. numer of cells showing repair and the mean number of grains per nucleus. The influence of radiation dose and of the duration of radioactive thymidine incubation were also examined. To test for a possible relationship between low mitotic index and repair capability, EAT cells were incubated in buffered salt media to lower the mitotic index. Cells kept in a buffered salt solution for 7 h show a marked drop in mitotic index compared to those incubated in minimal medium containing 15% fetal calf serum (MEM + FCS). This drop in mitotic index was reversible for up to 5 h, if cells were returned to MEM + FCS. Cells incubated in MEM + FCS also showed a decrease in mitotic activity compared to freshly drawn cells. This reduced mitotic index is approximately constant for up to 24 h. With the drop in mitotic index, EAT cells also show a drop in repair compared to freshly drawn cells. The repair capability of cells incubated in buffer can be restored by returning cells to MEM + FCS

Polymer microfiber meshes facilitate cardiac differentiation of c-kit{sup +} human cardiac stem cells

Energy Technology Data Exchange (ETDEWEB)

Kan, Lijuan [Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (United States); Thayer, Patrick [Department of Chemical Engineering, School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA (United States); Fan, Huimin [Research Institute of Heart Failure, Shanghai East Hospital of Tongji University, Shanghai (China); Ledford, Benjamin; Chen, Miao [Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (United States); Goldstein, Aaron [Department of Chemical Engineering, School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA (United States); Cao, Guohua [School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, VA (United States); He, Jia-Qiang, E-mail: jiahe@vt.edu [Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, VA (United States)

2016-09-10

Electrospun microfiber meshes have been shown to support the proliferation and differentiation of many types of stem cells, but the phenotypic fate of c-kit{sup +} human cardiac stem cells (hCSCs) have not been explored. To this end, we utilized thin (~5 µm) elastomeric meshes consisting of aligned 1.7 µm diameter poly (ester-urethane urea) microfibers as substrates to examine their effect on hCSC viability, morphology, proliferation, and differentiation relative to cells cultured on tissue culture polystyrene (TCPS). The results showed that cells on microfiber meshes displayed an elongated morphology aligned in the direction of fiber orientation, lower proliferation rates, but increased expressions of genes and proteins majorly associated with cardiomyocyte phenotype. The early (NK2 homeobox 5, Nkx2.5) and late (cardiac troponin I, cTnI) cardiomyocyte genes were significantly increased on meshes (Nkx=2.5 56.2±13.0, cTnl=2.9±0.56,) over TCPS (Nkx2.5=4.2±0.9, cTnl=1.6±0.5, n=9, p<0.05 for both groups) after differentiation. In contrast, expressions of smooth muscle markers, Gata6 and myosin heavy chain (SM-MHC), were decreased on meshes. Immunocytochemical analysis with cardiac antibody exhibited the similar pattern of above cardiac differentiation. We conclude that aligned microfiber meshes are suitable for guiding cardiac differentiation of hCSCs and may facilitate stem cell-based therapies for treatment of cardiac diseases. - Highlights: • First study to characterize c-kit{sup +} human cardiac stem cells on microfiber meshes. • Microfiber meshes seem reducing cell proliferation, but no effect on cell viability. • Microfiber meshes facilitate the elongation of human cardiac stem cells in culture. • Cardiac but not smooth muscle differentiation were enhanced on microfiber meshes. • Microfiber meshes may be used as cardiac patches in cell-based cardiac therapy.

Repair of furocoumarin adducts in mammalian cells

International Nuclear Information System (INIS)

Zolan, M.E.; Smith, C.A.; Hanawalt, P.C.

1984-01-01

DNA repair was studied in cultured mammalian cells treated with the furocoumarins 8-methoxypsoralen (8-MOP), aminomethyl trioxsalen, or angelicin and irradiated with near UV light. The amount of DNA cross-linked by 8-MOP in normal human cells decreased by about one-half in 24 hours after treatment; no decrease was observed in xeroderma pigmentosum cells, group A. At present, it is not known to what extent this decrease represents complete repair events at the sites of cross-links. Furocoumarin adducts elicited excision repair in normal human and monkey cells but not in xeroderma pigmentosum group A cells. This excision repair resembled in several aspects that elicited by pyrimidine dimers, formed in DNA by irradiation with 254-nm UV light; however, it appeared that for at least 8-MOP and aminomethyl trioxsalen, removal of adducts was not as efficient as was the removal of pyrimidine dimers. A comparison was also made of repair in the 172-base-pair repetitive alpha-DNA component of monkey cells to repair in the bulk of the genome. Although repair elicited by pyrimidine dimers in alpha-DNA was the same as in the bulk DNA, that following treatment of cells with either aminomethyl trioxsalen or angelicin and near UV was markedly deficient in alpha-DNA. This deficiency reflected the removal of fewer adducts from alpha-DNA after the same initial adduct frequencies. These results could mean that each furocoumarin may produce several structurally distinct adducts to DNA in cells and that the capacity of cellular repair systems to remove these various adducts may vary greatly

Biomaterials for cardiac regeneration

CERN Document Server

Ruel, Marc

2015-01-01

This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

From developmental biology to heart repair

NARCIS (Netherlands)

Campione, M.; Moorman, A. F.; Kelly, R. G.

2007-01-01

Advances in our understanding of cardiac development have fuelled research into cellular approaches to myocardial repair of the damaged heart. In this collection of reviews we present recent advances into the basic mechanisms of heart development and the resident and non-resident progenitor cell

Isolating human DNA repair genes using rodent-cell mutants

International Nuclear Information System (INIS)

Thompson, L.H.; Weber, C.A.; Brookman, K.W.; Salazar, E.P.; Stewart, S.A.; Mitchell, D.L.

1987-01-01

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

DNA repair and radiation sensitivity in mammalian cells

International Nuclear Information System (INIS)

Chen, D.J.C.; Stackhouse, M.; Chen, D.S.

1993-01-01

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

Micromanaging cardiac regeneration : Targeted delivery of microRNAs for cardiac repair and regeneration

NARCIS (Netherlands)

Kamps, Jan A.A.M.; Krenning, Guido

2016-01-01

The loss of cardiomyocytes during injury and disease can result in heart failure and sudden death, while the adult heart has a limited capacity for endogenous regeneration and repair. Current stem cell-based regenerative medicine approaches modestly improve cardiomyocyte survival, but offer

Efficient Isolation of Cardiac Stem Cells from Brown Adipose

Directory of Open Access Journals (Sweden)

Zhiqiang Liu

2010-01-01

Full Text Available Cardiac stem cells represent a logical cell type to exploit in cardiac regeneration. The efficient harvest of cardiac stem cells from a suitable source would turn promising in cardiac stem cell therapy. Brown adipose was recently found to be a new source of cardiac stem cells, instrumental to myocardial regeneration. Unfortunately, an efficient method for the cell isolation is unavailable so far. In our study we have developed a new method for the efficient isolation of cardiac stem cells from brown adipose by combining different enzymes. Results showed that the total cell yield dramatically increased (more than 10 times, P<.01 compared with that by previous method. The content of CD133-positive cells (reported to differentiate into cardiomyocytes with a high frequency was much higher than that in the previous report (22.43% versus 3.5%. Moreover, the isolated cells could be the efficiently differentiated into functional cardiomyocytes in optimized conditions. Thus, the new method we established would be of great use in further exploring cardiac stem cell therapy.

Repair of traumatized mammalian hair cells via sea anemone repair proteins.

Science.gov (United States)

Tang, Pei-Ciao; Smith, Karen Müller; Watson, Glen M

2016-08-01

Mammalian hair cells possess only a limited ability to repair damage after trauma. In contrast, sea anemones show a marked capability to repair damaged hair bundles by means of secreted repair proteins (RPs). Previously, it was found that recovery of traumatized hair cells in blind cavefish was enhanced by anemone-derived RPs; therefore, the ability of anemone RPs to assist recovery of damaged hair cells in mammals was tested here. After a 1 h incubation in RP-enriched culture media, uptake of FM1-43 by experimentally traumatized murine cochlear hair cells was restored to levels comparable to those exhibited by healthy controls. In addition, RP-treated explants had significantly more normally structured hair bundles than time-matched traumatized control explants. Collectively, these results indicate that anemone-derived RPs assist in restoring normal function and structure of experimentally traumatized hair cells of the mouse cochlea. © 2016. Published by The Company of Biologists Ltd.

Repair of radiation damage in mammalian cells

Energy Technology Data Exchange (ETDEWEB)

Setlow, R.B.

1981-01-01

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.

Repair of radiation damage in mammalian cells

International Nuclear Information System (INIS)

Setlow, R.B.

1981-01-01

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

DNA repair in murine embryonic stem cells and differentiated cells

International Nuclear Information System (INIS)

Tichy, Elisia D.; Stambrook, Peter J.

2008-01-01

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

Cell sensitivity to irradiation and DNA repair processes

International Nuclear Information System (INIS)

Kozubek, S.; Krasavin, E.A.

1984-01-01

A new model of oxygen effect realisation is proposed for E.coli cells. The model explains differencies in oxygen enhancement ratio (OER) between wild type cells and repair deficient mutants. These differencies are logically linked to corresponding defects in repair systems. A quantitative analysis has been performed. The dependence of OER and cell sensitivity on the properties of cultivation medium is considered, too. Decreasing OER and increasing sensitivity in poor conditions are explained as the consequence of the shift of repair capacity from slow to fast repair system

Small Engine, Big Power: MicroRNAs as Regulators of Cardiac Diseases and Regeneration

Directory of Open Access Journals (Sweden)

Darukeshwara Joladarashi

2014-09-01

Full Text Available Cardiac diseases are the predominant cause of human mortality in the United States and around the world. MicroRNAs (miRNAs are small non-coding RNAs that have been shown to modulate a wide range of biological functions under various pathophysiological conditions. miRNAs alter target expression by post-transcriptional regulation of gene expression. Numerous studies have implicated specific miRNAs in cardiovascular development, pathology, regeneration and repair. These observations suggest that miRNAs are potential therapeutic targets to prevent or treat cardiovascular diseases. This review focuses on the emerging role of miRNAs in cardiac development, pathogenesis of cardiovascular diseases, cardiac regeneration and stem cell-mediated cardiac repair. We also discuss the novel diagnostic and therapeutic potential of these miRNAs and their targets in patients with cardiac diseases.

Thymosin β4: multiple functions in protection, repair and regeneration of the mammalian heart.

Science.gov (United States)

Bollini, Sveva; Riley, Paul R; Smart, Nicola

2015-01-01

Despite recent improvements in interventional medicine, cardiovascular disease still represents the major cause of morbidity worldwide, with myocardial infarction being the most common cardiac injury. This has sustained the development of several regenerative strategies based on the use of stem cells and tissue engineering approaches in order to achieve cardiac repair and regeneration by enhancing coronary neovascularization, modulating acute inflammation and supporting myocardial regeneration to provide new functional muscle. The actin monomer binding peptide, Thymosin β4 (Tβ4), has recently been described as a powerful regenerative agent with angiogenic, anti-inflammatory and cardioprotective effects on the heart and which specifically acts on its resident cardiac progenitor cells. In this review we will discuss the state of the art regarding the many roles of Tβ4 in preserving and regenerating the mammalian heart, with specific attention to its ability to activate the quiescent adult epicardium and specific subsets of epicardial progenitor cells for repair. The therapeutic potential of Tβ4 for the treatment of cardiac failure is herein evaluated alongside existing, emerging and prospective novel treatments.

Capacity of ultraviolet-induced DNA repair in human glioma cells

Energy Technology Data Exchange (ETDEWEB)

Itoh, Hiroji

1987-04-01

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.

Induced repair and mutagenesis in animal cells

International Nuclear Information System (INIS)

Takimoto, Koichi

1981-01-01

Induced repair and mutagenesis of animal cells against UV were studied in contrast with SOS repair of E. coli primarily by the use of viruses. Since UV-enhanced reactivation is a phenomenon similar to UV-reactivation (mutagenesis) and the presence of lesion bypass synthsis has been suggested, UV-enhanced reactivation has several common aspects with SOS reactivation of E. coli. However, correlation is not necessarily noted between increase in the viral survival rate and mutagenesis, nor do protease blockers exert any effect. Therefore, SOS repair of E. coli may have different mechansms from induced repair and mutagenesis in animal cells. (Ueda, J.)

Pre-transplantation specification of stem cells to cardiac lineage for regeneration of cardiac tissue.

Science.gov (United States)

Mayorga, Maritza; Finan, Amanda; Penn, Marc

2009-03-01

Myocardial infarction (MI) is a lead cause of mortality in the Western world. Treatment of acute MI is focused on restoration of antegrade flow which inhibits further tissue loss, but does not restore function to damaged tissue. Chronic therapy for injured myocardial tissue involves medical therapy that attempts to minimize pathologic remodeling of the heart. End stage therapy for chronic heart failure (CHF) involves inotropic therapy to increase surviving cardiac myocyte function or mechanical augmentation of cardiac performance. Not until the point of heart transplantation, a limited resource at best, does therapy focus on the fundamental problem of needing to replace injured tissue with new contractile tissue. In this setting, the potential for stem cell therapy has garnered significant interest for its potential to regenerate or create new contractile cardiac tissue. While to date adult stem cell therapy in clinical trials has suggested potential benefit, there is waning belief that the approaches used to date lead to regeneration of cardiac tissue. As the literature has better defined the pathways involved in cardiac differentiation, preclinical studies have suggested that stem cell pretreatment to direct stem cell differentiation prior to stem cell transplantation may be a more efficacious strategy for inducing cardiac regeneration. Here we review the available literature on pre-transplantation conditioning of stem cells in an attempt to better understand stem cell behavior and their readiness in cell-based therapy for myocardial regeneration.

Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages

International Nuclear Information System (INIS)

Arsic, Nikola; Mamaeva, Daria; Lamb, Ned J.; Fernandez, Anne

2008-01-01

Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal β III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders

Muscle-derived stem cells isolated as non-adherent population give rise to cardiac, skeletal muscle and neural lineages.

Science.gov (United States)

Arsic, Nikola; Mamaeva, Daria; Lamb, Ned J; Fernandez, Anne

2008-04-01

Stem cells with the ability to differentiate in specialized cell types can be extracted from a wide array of adult tissues including skeletal muscle. Here we have analyzed a population of cells isolated from skeletal muscle on the basis of their poor adherence on uncoated or collagen-coated dishes that show multi-lineage differentiation in vitro. When analysed under proliferative conditions, these cells express stem cell surface markers Sca-1 (65%) and Bcrp-1 (80%) but also MyoD (15%), Neuronal beta III-tubulin (25%), GFAP (30%) or Nkx2.5 (1%). Although capable of growing as non-attached spheres for months, when given an appropriate matrix, these cells adhere giving rise to skeletal muscle, neuronal and cardiac muscle cell lineages. A similar cell population could not be isolated from either bone marrow or cardiac tissue suggesting their specificity to skeletal muscle. When injected into damaged muscle, these non-adherent muscle-derived cells are retrieved expressing Pax7, in a sublaminar position characterizing satellite cells and participate in forming new myofibers. These data show that a non-adherent stem cell population can be specifically isolated and expanded from skeletal muscle and upon attachment to a matrix spontaneously differentiate into muscle, cardiac and neuronal lineages in vitro. Although competing with resident satellite cells, these cells are shown to significantly contribute to repair of injured muscle in vivo supporting that a similar muscle-derived non-adherent cell population from human muscle may be useful in treatment of neuromuscular disorders.

Improving cardiac myocytes performance by CNTs platforms

Directory of Open Access Journals (Sweden)

Valentina eMartinelli

2013-09-01

Full Text Available The application of nanotechnology to the cardiovascular system has increasingly caught scientists’ attention as a potentially powerful tool for the development of new generation devices able to interface, repair or boost the performance of cardiac tissue. Carbon nanotubes (CNTs are considered as promising materials for nanomedicine applications in general and have been recently tested towards excitable cell growth. CNTs are cylindrically shaped structures made up of rolled-up graphene sheets, with unique electrical, thermal and mechanical properties, able to effectively conducting electrical current in electrochemical interfaces. CNTs-based scaffolds have been recently found to support the in vitro growth of cardiac cells: in particular, their ability to improve cardiomyocytes proliferation, maturation and electrical behavior are making CNTs extremely attractive for the development and exploitation of interfaces able to impact on cardiac cells physiology and function.

Adaptive repair induced by small doses of γ radiation in repair-defective human cells

International Nuclear Information System (INIS)

Zasukhina, G.D.; L'vova, G.N.; Vasil'eva, I.M.; Sinel'shchikova, T.A.; Semyachkina, A.N.

1993-01-01

Adaptive repair induced by small doses of gamma radiation was studied in repair-defective xeroderma pigmentosum, gout, and homocystinuria cells. The adaptation of cells induced by small doses of radiation was estimated after subsequent exposure to gamma radiation, 4-nitroquinoline-1-oxide, and N-methyl-N-nitro-N-nitrosoguanidine by three methods: (1) by the reduction in DNA breaks; (2) by induction of resistant DNA synthesis; and (3) by increased reactivation of vaccinia virus. The three cell types in response to the three different mutagens revealed differences in the mechanism of cell defense in excision repair, in the adaptive response, and in Weigl reactivation

DNA repair in human bronchial epithelial cells

International Nuclear Information System (INIS)

Fornace, A.J. Jr.; Lechner, J.F.; Grafstrom, R.C.; Harris, C.C.

1982-01-01

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

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

International Nuclear Information System (INIS)

Yatani, Ryuichi; Tohgo, Yukihiro; Kunishima, Nobuyoshi.

1975-01-01

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.)

Regulation of DNA repair processes in mammalian cell

International Nuclear Information System (INIS)

Bil'din, V.N.; Sergina, T.B.; Zhestyanikov, V.D.

1992-01-01

A study was made of the repair of ionizing radiation-induced DNA single-strand breaks (SSB) in proliferating and quiescent mouse Swiss 3T6 cells and in those stimulated from the quiet status by epidermal growth factor in combination with insulin, in the presence of specific inhibitors of DNA polymerase α and β (aphidicolin) and DNA polymerase β (2', 3'-dideoxythjymidine-5'-triphosphate). The repair of DNA SSB induced by X-ray-irradiation (10 Gy) or by γ-ray irradiation (150 Gy) is more sensitive to aphidicolin and mitogen-simulated cells three times stronger than in proliferating cells. The influence of 2', 3'-dideoxythymidine-5'-triphosphate on the rate of DNA SSB repair in cells of all the three types does not differ. Thus, the decrease in DNA repair efficiency in quiescent cells is connected with a decrease in the activity of aphidicolin-sensitive DNA polymerase, apparently DNA polymerase α

DNA repair in mammalian cells exposed to combinations of carcinogenic agents

International Nuclear Information System (INIS)

Setlow, R.B.; Ahmed, F.E.

1979-01-01

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

DNA Repair in Human Pluripotent Stem Cells Is Distinct from That in Non-Pluripotent Human Cells

Science.gov (United States)

Luo, Li Z.; Park, Sang-Won; Bates, Steven E.; Zeng, Xianmin; Iverson, Linda E.; O'Connor, Timothy R.

2012-01-01

The potential for human disease treatment using human pluripotent stem cells, including embryonic stem cells and induced pluripotent stem cells (iPSCs), also carries the risk of added genomic instability. Genomic instability is most often linked to DNA repair deficiencies, which indicates that screening/characterization of possible repair deficiencies in pluripotent human stem cells should be a necessary step prior to their clinical and research use. In this study, a comparison of DNA repair pathways in pluripotent cells, as compared to those in non-pluripotent cells, demonstrated that DNA repair capacities of pluripotent cell lines were more heterogeneous than those of differentiated lines examined and were generally greater. Although pluripotent cells had high DNA repair capacities for nucleotide excision repair, we show that ultraviolet radiation at low fluxes induced an apoptotic response in these cells, while differentiated cells lacked response to this stimulus, and note that pluripotent cells had a similar apoptotic response to alkylating agent damage. This sensitivity of pluripotent cells to damage is notable since viable pluripotent cells exhibit less ultraviolet light-induced DNA damage than do differentiated cells that receive the same flux. In addition, the importance of screening pluripotent cells for DNA repair defects was highlighted by an iPSC line that demonstrated a normal spectral karyotype, but showed both microsatellite instability and reduced DNA repair capacities in three out of four DNA repair pathways examined. Together, these results demonstrate a need to evaluate DNA repair capacities in pluripotent cell lines, in order to characterize their genomic stability, prior to their pre-clinical and clinical use. PMID:22412831

DNA-radiosensitivity and repair in mammolian cells

International Nuclear Information System (INIS)

Proskuryakov, S.Ya.; Ivannik, B.P.; Ryabchenko, N.I.

1979-01-01

Determination was made of the formation and repair of single-stranded DNA breaks (SB) in cells of rat thymus and liver and Ehrlich's ascites tumor (EAT) with the use of the method of low-gradient viscosimetry of alkaline cell lysates. The radiochemical yield of single-stranded breaks (Gsub(SB)) induced by irradiation of animals is 41.2 eV/break for hepatocytes, 96.8 eV/break, for thymocytes, and 129.7 eV/break, for EAT cells. The half-recovery time of single-stranded DNA breaks for cells of thymus and EAT exposed in vivo is 16.0 and 5.1 s -1 , correspondingly. In hepatocytes exposed in vivo and in vitro no repairs occurs for 3 h. Under conditions of inhibition of SB repair, when suspensions of thymocytes and hepatocytes were exposed in vitro at 4 deg C, Gsub(SB) is 35.5 and 38.7 eV/break, respectively. The analysis of the data obtained prompts the conclusion that under in vivo conditions, there is a correlation between DNA radiosensitivity and the rate of repair processes

Inspiration from heart development: Biomimetic development of functional human cardiac organoids.

Science.gov (United States)

Richards, Dylan J; Coyle, Robert C; Tan, Yu; Jia, Jia; Wong, Kerri; Toomer, Katelynn; Menick, Donald R; Mei, Ying

2017-10-01

Recent progress in human organoids has provided 3D tissue systems to model human development, diseases, as well as develop cell delivery systems for regenerative therapies. While direct differentiation of human embryoid bodies holds great promise for cardiac organoid production, intramyocardial cell organization during heart development provides biological foundation to fabricate human cardiac organoids with defined cell types. Inspired by the intramyocardial organization events in coronary vasculogenesis, where a diverse, yet defined, mixture of cardiac cell types self-organizes into functional myocardium in the absence of blood flow, we have developed a defined method to produce scaffold-free human cardiac organoids that structurally and functionally resembled the lumenized vascular network in the developing myocardium, supported hiPSC-CM development and possessed fundamental cardiac tissue-level functions. In particular, this development-driven strategy offers a robust, tunable system to examine the contributions of individual cell types, matrix materials and additional factors for developmental insight, biomimetic matrix composition to advance biomaterial design, tissue/organ-level drug screening, and cell therapy for heart repair. Copyright © 2017 Elsevier Ltd. All rights reserved.

Repetitious nature of repaired DNA in mammalian cells

International Nuclear Information System (INIS)

1978-01-01

The report consists of three appendices, as follows: summary of preliminary studies of the comparative DNA repair in normal lymphoblastoid and Burkitt's lymphoma cell lines; nonuniform reassociation of human lymphoblastoid cell DNA repair replicated following methyl methane sulfonate treatment; and preliminary DNA single-strand breakage studies in the L5178Y cell line

Skin appendage-derived stem cells: cell biology and potential for wound repair.

Science.gov (United States)

Xie, Jiangfan; Yao, Bin; Han, Yutong; Huang, Sha; Fu, Xiaobing

2016-01-01

Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. These stem cells also participate in the repair of the epidermis after injuries, inducing restoration of tissue integrity and function of damaged tissue. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. In this review, we summarize the current knowledge of skin appendage-derived stem cells, including their fundamental characteristics, their preferentially expressed biomarkers, and their potential contribution involved in wound repair. Finally, we will also discuss current strategies, future applications, and limitations of these stem cells, attempting to provide some perspectives on optimizing the available therapy in cutaneous repair and regeneration.

Translational findings from cardiovascular stem cell research.

Science.gov (United States)

Mazhari, Ramesh; Hare, Joshua M

2012-01-01

The possibility of using stem cells to regenerate damaged myocardium has been actively investigated since the late 1990s. Consistent with the traditional view that the heart is a "postmitotic" organ that possesses minimal capacity for self-repair, much of the preclinical and clinical work has focused exclusively on introducing stem cells into the heart, with the hope of differentiation of these cells into functioning cardiomyocytes. This approach is ongoing and retains promise but to date has yielded inconsistent successes. More recently, it has become widely appreciated that the heart possesses endogenous repair mechanisms that, if adequately stimulated, might regenerate damaged cardiac tissue from in situ cardiac stem cells. Accordingly, much recent work has focused on engaging and enhancing endogenous cardiac repair mechanisms. This article reviews the literature on stem cell-based myocardial regeneration, placing emphasis on the mutually enriching interaction between basic and clinical research. Copyright © 2012 Elsevier Inc. All rights reserved.

Cardiac Cells Beating in Culture: A Laboratory Exercise

Science.gov (United States)

Weaver, Debora

2007-01-01

This article describes how to establish a primary tissue culture, where cells are taken directly from an organ of a living animal. Cardiac cells are taken from chick embryos and transferred to culture dishes. These cells are not transformed and therefore have a limited life span. However, the unique characteristics of cardiac cells are maintained…

Enhancement of myocardial regeneration through genetic engineering of cardiac progenitor cells expressing Pim-1 kinase.

Science.gov (United States)

Fischer, Kimberlee M; Cottage, Christopher T; Wu, Weitao; Din, Shabana; Gude, Natalie A; Avitabile, Daniele; Quijada, Pearl; Collins, Brett L; Fransioli, Jenna; Sussman, Mark A

2009-11-24

Despite numerous studies demonstrating the efficacy of cellular adoptive transfer for therapeutic myocardial regeneration, problems remain for donated cells with regard to survival, persistence, engraftment, and long-term benefits. This study redresses these concerns by enhancing the regenerative potential of adoptively transferred cardiac progenitor cells (CPCs) via genetic engineering to overexpress Pim-1, a cardioprotective kinase that enhances cell survival and proliferation. Intramyocardial injections of CPCs overexpressing Pim-1 were given to infarcted female mice. Animals were monitored over 4, 12, and 32 weeks to assess cardiac function and engraftment of Pim-1 CPCs with echocardiography, in vivo hemodynamics, and confocal imagery. CPCs overexpressing Pim-1 showed increased proliferation and expression of markers consistent with cardiogenic lineage commitment after dexamethasone exposure in vitro. Animals that received CPCs overexpressing Pim-1 also produced greater levels of cellular engraftment, persistence, and functional improvement relative to control CPCs up to 32 weeks after delivery. Salutary effects include reduction of infarct size, greater number of c-kit(+) cells, and increased vasculature in the damaged region. Myocardial repair is significantly enhanced by genetic engineering of CPCs with Pim-1 kinase. Ex vivo gene delivery to enhance cellular survival, proliferation, and regeneration may overcome current limitations of stem cell-based therapeutic approaches.

Repair processes for photochemical damage in mammalian cells

International Nuclear Information System (INIS)

Cleaver, J.E.

1974-01-01

Repair processes for photochemical damage in cells following uv irradiation are reviewed. Cultured fibroblast cells from human patients with xeroderma pigmentosum were used as an example to illustrate aspects of repair of injuries to DNA and proteins. (250 references) (U.S.)

DNA-repair synthesis in ataxia telangiectasia lymphoblastoid cells

Energy Technology Data Exchange (ETDEWEB)

Ford, M.D.; Houldsworth, J.; Lavin, M.F. (Queensland Univ., Brisbane (Australia). Dept. of Biochemistry)

1981-12-01

The ability of a number of Epstein-Barr virus-transformed lymphoblastoid cells from ataxia telangiectasia (AT) patients to repair ..gamma..-radiation damage to DNA was determined. All of these AT cells were previously shown to be hypersensitive to ..gamma..-radiation. Two methods were used to determine DNA-repair synthesis: isopycnic gradient analysis and a method employing hydroxyurea to inhibit semiconservative DNA synthesis. Control, AT heterozygote and AT homozygote cells were demonstrated to have similar capacities for repair of radiation damage to DNA. In addition at high radiation doses (10-40 krad) the extent of inhibition of DNA synthesis was similar in the different cell types.

Directed fusion of cardiac spheroids into larger heterocellular microtissues enables investigation of cardiac action potential propagation via cardiac fibroblasts

Science.gov (United States)

Markes, Alexander R.; Okundaye, Amenawon O.; Qu, Zhilin; Mende, Ulrike; Choi, Bum-Rak

2018-01-01

Multicellular spheroids generated through cellular self-assembly provide cytoarchitectural complexities of native tissue including three-dimensionality, extensive cell-cell contacts, and appropriate cell-extracellular matrix interactions. They are increasingly suggested as building blocks for larger engineered tissues to achieve shapes, organization, heterogeneity, and other biomimetic complexities. Application of these tissue culture platforms is of particular importance in cardiac research as the myocardium is comprised of distinct but intermingled cell types. Here, we generated scaffold-free 3D cardiac microtissue spheroids comprised of cardiac myocytes (CMs) and/or cardiac fibroblasts (CFs) and used them as building blocks to form larger microtissues with different spatial distributions of CMs and CFs. Characterization of fusing homotypic and heterotypic spheroid pairs revealed an important influence of CFs on fusion kinetics, but most strikingly showed rapid fusion kinetics between heterotypic pairs consisting of one CF and one CM spheroid, indicating that CMs and CFs self-sort in vitro into the intermixed morphology found in the healthy myocardium. We then examined electrophysiological integration of fused homotypic and heterotypic microtissues by mapping action potential propagation. Heterocellular elongated microtissues which recapitulate the disproportionate CF spatial distribution seen in the infarcted myocardium showed that action potentials propagate through CF volumes albeit with significant delay. Complementary computational modeling revealed an important role of CF sodium currents and the spatial distribution of the CM-CF boundary in action potential conduction through CF volumes. Taken together, this study provides useful insights for the development of complex, heterocellular engineered 3D tissue constructs and their engraftment via tissue fusion and has implications for arrhythmogenesis in cardiac disease and repair. PMID:29715271

Directed fusion of cardiac spheroids into larger heterocellular microtissues enables investigation of cardiac action potential propagation via cardiac fibroblasts.

Directory of Open Access Journals (Sweden)

Tae Yun Kim

Full Text Available Multicellular spheroids generated through cellular self-assembly provide cytoarchitectural complexities of native tissue including three-dimensionality, extensive cell-cell contacts, and appropriate cell-extracellular matrix interactions. They are increasingly suggested as building blocks for larger engineered tissues to achieve shapes, organization, heterogeneity, and other biomimetic complexities. Application of these tissue culture platforms is of particular importance in cardiac research as the myocardium is comprised of distinct but intermingled cell types. Here, we generated scaffold-free 3D cardiac microtissue spheroids comprised of cardiac myocytes (CMs and/or cardiac fibroblasts (CFs and used them as building blocks to form larger microtissues with different spatial distributions of CMs and CFs. Characterization of fusing homotypic and heterotypic spheroid pairs revealed an important influence of CFs on fusion kinetics, but most strikingly showed rapid fusion kinetics between heterotypic pairs consisting of one CF and one CM spheroid, indicating that CMs and CFs self-sort in vitro into the intermixed morphology found in the healthy myocardium. We then examined electrophysiological integration of fused homotypic and heterotypic microtissues by mapping action potential propagation. Heterocellular elongated microtissues which recapitulate the disproportionate CF spatial distribution seen in the infarcted myocardium showed that action potentials propagate through CF volumes albeit with significant delay. Complementary computational modeling revealed an important role of CF sodium currents and the spatial distribution of the CM-CF boundary in action potential conduction through CF volumes. Taken together, this study provides useful insights for the development of complex, heterocellular engineered 3D tissue constructs and their engraftment via tissue fusion and has implications for arrhythmogenesis in cardiac disease and repair.

Materializing Heart Regeneration: Biomimicry of Key Observations in Cell Transplantation Therapies and Natural Cardiac Regeneration

Science.gov (United States)

Kong, Yen P.; Jongpaiboonkit, Leena

2016-07-01

New regenerative paradigms are needed to address the growing global problem of heart failure as existing interventions are unsatisfactory. Outcomes from the current paradigm of cell transplantation have not been stellar but the mechanistic knowledge learned from them is instructive in the development of future paradigms. An emerging biomaterial-based approach incorporating key mechanisms and additional ones scrutinized from the process of natural heart regeneration in zebrafish may become the next evolution in cardiac repair. We highlight, with examples, tested key concepts and pivotal ones that may be integrated into a successful therapy.

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

International Nuclear Information System (INIS)

Hansson, J.; Keyse, S.M.; Lindahl, T.; Wood, R.D.

1991-01-01

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

Sustained co-delivery of BIO and IGF-1 by a novel hybrid hydrogel system to stimulate endogenous cardiac repair in myocardial infarcted rat hearts.

Science.gov (United States)

Fang, Rui; Qiao, Shupei; Liu, Yi; Meng, Qingyuan; Chen, Xiongbiao; Song, Bing; Hou, Xiaolu; Tian, Weiming

2015-01-01

Dedifferentiation and proliferation of endogenous cardiomyocytes in situ can effectively improve cardiac repair following myocardial infarction (MI). 6-Bromoindirubin-3-oxime (BIO) and insulin-like growth factor 1 (IGF-1) are two potent factors that promote cardiomyocyte survival and proliferation. However, their delivery for sustained release in MI-affected areas has proved to be challenging. In the current research, we present a study on the sustained co-delivery of BIO and IGF-1 in a hybrid hydrogel system to simulate endogenous cardiac repair in an MI rat model. Both BIO and IGF-1 were efficiently encapsulated in gelatin nanoparticles, which were later cross-linked with the oxidized alginate to form a novel hybrid hydrogel system. The in vivo results indicated that the hybrid system could enhance the proliferation of cardiomyocytes in situ and could promote revascularization around the MI sites, allowing improved cardiac function. Taken together, we concluded that the hybrid hydrogel system can co-deliver BIO and IGF-1 to areas of MI and thus improve cardiac function by promoting the proliferation of cardiomyocytes and revascularization.

Sustained co-delivery of BIO and IGF-1 by a novel hybrid hydrogel system to stimulate endogenous cardiac repair in myocardial infarcted rat hearts

Science.gov (United States)

Fang, Rui; Qiao, Shupei; Liu, Yi; Meng, Qingyuan; Chen, Xiongbiao; Song, Bing; Hou, Xiaolu; Tian, Weiming

2015-01-01

Dedifferentiation and proliferation of endogenous cardiomyocytes in situ can effectively improve cardiac repair following myocardial infarction (MI). 6-Bromoindirubin-3-oxime (BIO) and insulin-like growth factor 1 (IGF-1) are two potent factors that promote cardiomyocyte survival and proliferation. However, their delivery for sustained release in MI-affected areas has proved to be challenging. In the current research, we present a study on the sustained co-delivery of BIO and IGF-1 in a hybrid hydrogel system to simulate endogenous cardiac repair in an MI rat model. Both BIO and IGF-1 were efficiently encapsulated in gelatin nanoparticles, which were later cross-linked with the oxidized alginate to form a novel hybrid hydrogel system. The in vivo results indicated that the hybrid system could enhance the proliferation of cardiomyocytes in situ and could promote revascularization around the MI sites, allowing improved cardiac function. Taken together, we concluded that the hybrid hydrogel system can co-deliver BIO and IGF-1 to areas of MI and thus improve cardiac function by promoting the proliferation of cardiomyocytes and revascularization. PMID:26251592

Early postoperative remodelling following repair of tetralogy of Fallot utilising unsedated cardiac magnetic resonance: a pilot study.

Science.gov (United States)

DiLorenzo, Michael P; Goldmuntz, Elizabeth; Nicolson, Susan C; Fogel, Mark A; Mercer-Rosa, Laura

2018-05-01

IntroductionThe right ventricular adaptations early after surgery in infants with tetralogy of Fallot are important to understand the changes that occur later on in life; this physiology has not been fully delineated. We sought to assess early postoperative right ventricular remodelling in patients with tetralogy of Fallot by cardiac MRI.Materials and methodSubjects with tetralogy of Fallot under 1 year of age were recruited following complete surgical repair for tetralogy of Fallot. Protocol-based cardiac MRI to assess anatomy, function, and flows was performed before hospital discharge using the feed and sleep technique, an unsedated imaging technique. MRI was completed in 16 subjects at a median age of 77 days (interquartile range 114). There was normal ventricular ejection fraction and indexed right ventricular end-diastolic volume (48±13 cc/m2), but elevated right ventricular mass (z score 6.2±2.4). Subjects requiring a transannular patch or right ventricle to pulmonary artery conduit had moderate pulmonary insufficiency (regurgitant fraction 27±16%).DiscussionEarly right ventricular remodelling after surgical repair for tetralogy of Fallot is characterised by significant pulmonary regurgitation, right ventricular hypertrophy, and lack of dilation. Performing cardiac MRI using the feed and sleep technique is feasible in infants younger than 5 months. These results might open new avenues to study longitudinal right ventricular changes in tetralogy of Fallot and to further explore the utility of unsedated MRI in patients with other types of CHDs.

DNA repair capacity and rate of excision repair in UV-irradiated mammalian cells

International Nuclear Information System (INIS)

Inoue, Masao; Takebe, Hiraku.

1978-01-01

Repair capacities of five mammalian cell strains were measured by colony-forming ability, HCR of UV-irradiated virus, UDS, pyrimidine dimer excision, and semi-conservative DNA replication. Colony-forming ability of UV-irradiated cells was high for human amnion FL cells and mouse L cells, slightly low for African green monkey CV-1 cells, and extremely low for xeroderma pigmentosum cells. HCR of UV-irradiated Herpes simplex virus was high in CV-1 cells, FL and normal human fibroblast cells, low in both XP and L cells. The amount of UDS was high in FL and normal human fibroblast cells, considerably low in CV-1 cells, and essentially no UDS was observed in XP cells. Rate of UDS after UV-irradiation was slower for CV-1 cells than FL and human fibroblast cells. Rate of the excision of thymine-containing dimers from the acid-insoluble fraction during post-irradiation incubation of the cells was rapid in FL and normal human cells and slow in CV-1 cells, and no excision took place in XP cells. Semi-conservative DNA synthesis was reduced after UV-irradiation in all cell lines, but subsequently recovered in FL, normal human and CV-1 cells. The onset of recovery was 4 h after UV-irradiation for FL and normal human cells, but about 6 h for CV-1 cells. The apparent intermediate repair of CV-1 cells except for HCR may be related to the slow rate of excision repair. ''Patch and cut'' model is more favorable than ''cut and patch'' model to elucidate these results. (auth.)

Stem Cells for Cardiac Regeneration by Cell Therapy and Myocardial Tissue Engineering

Science.gov (United States)

Wu, Jun; Zeng, Faquan; Weisel, Richard D.; Li, Ren-Ke

Congestive heart failure, which often occurs progressively following a myocardial infarction, is characterized by impaired myocardial perfusion, ventricular dilatation, and cardiac dysfunction. Novel treatments are required to reverse these effects - especially in older patients whose endogenous regenerative responses to currently available therapies are limited by age. This review explores the current state of research for two related approaches to cardiac regeneration: cell therapy and tissue engineering. First, to evaluate cell therapy, we review the effectiveness of various cell types for their ability to limit ventricular dilatation and promote functional recovery following implantation into a damaged heart. Next, to assess tissue engineering, we discuss the characteristics of several biomaterials for their potential to physically support the infarcted myocardium and promote implanted cell survival following cardiac injury. Finally, looking ahead, we present recent findings suggesting that hybrid constructs combining a biomaterial with stem and supporting cells may be the most effective approaches to cardiac regeneration.

Effects of combined mesenchymal stem cells and heme oxygenase-1 therapy on cardiac performance.

Science.gov (United States)

Zeng, Bin; Chen, Honglei; Zhu, Chengang; Ren, Xiaofeng; Lin, Guosheng; Cao, Feng

2008-10-01

Bone marrow mesenchymal stem cells (MSCs) have the potential to repair the infarcted myocardium and improve cardiac function. However, this approach is limited by its poor viability after transplantation, and controversy still exists over the mechanism by which MSCs contribute to the tissue repair. The human heme oxygenase-1 (hHO-1) was transfected into cultured MSCs using an adenoviral vector. 1 x 10(6) Ad-hHO-1-transfected MSCs (HO-1-MSCs) or Ad-Null-transfected MSCs (Null-MSCs) or PBS only (PBS group) were injected intramyocardially into rat hearts 1h after myocardial infarction. HO-1-MSCs survived in the infarcted myocardium, and expressed hHO-1 mRNA. The expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) was significantly enhanced in HO-1-MSCs-treated hearts. At the same time, there were significant reduction of TNF-alpha, IL-1-beta and IL-6 mRNA, and marked increase of IL-10 mRNA in HO-1-MSCs-treated hearts. Moreover, a further downregulation of proapoptotic protein, Bax, and a marked increase in microvessel density were observed in HO-1-MSCs-treated hearts. The infarct size and cardiac performance were also significantly improved in HO-1-MSCs-treated hearts. The combined approach improves MSCs survival and is superior to MSCs injection alone.

Development of heart muscle-cell diversity: a help or a hindrance for phenotyping embryonic stem cell-derived cardiomyocytes

NARCIS (Netherlands)

Fijnvandraat, Arnoud C.; Lekanne Deprez, Ronald H.; Moorman, Antoon F. M.

2003-01-01

Despite the advances in cardiovascular treatment, cardiac disease remains a major cause of morbidity in all industrialized countries. The extraordinary potential of (embryonic) stem cells for therapeutic purposes has revolutionized ideas about cardiac repair of diseased cardiac muscle to exciting

Induced Pluripotent Stem Cells 10 Years Later: For Cardiac Applications.

Science.gov (United States)

Yoshida, Yoshinori; Yamanaka, Shinya

2017-06-09

Induced pluripotent stem cells (iPSCs) are reprogrammed cells that have features similar to embryonic stem cells, such as the capacity of self-renewal and differentiation into many types of cells, including cardiac myocytes. Although initially the reprogramming efficiency was low, several improvements in reprogramming methods have achieved robust and efficient generation of iPSCs without genomic insertion of transgenes. iPSCs display clonal variations in epigenetic and genomic profiles and cellular behavior in differentiation. iPSC-derived cardiac myocytes (iPSC cardiac myocytes) recapitulate phenotypic differences caused by genetic variations, making them attractive human disease models, and are useful for drug discovery and toxicology testing. In addition, iPSC cardiac myocytes can help with patient stratification in regard to drug responsiveness. Furthermore, they can be used as source cells for cardiac regeneration in animal models. Here, we review recent progress in iPSC technology and its applications to cardiac diseases. © 2017 American Heart Association, Inc.

Cell-free assay measuring repair DNA synthesis in human fibroblasts

International Nuclear Information System (INIS)

Ciarrocchi, G.; Linn, S.

1978-01-01

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

Difference in membrane repair capacity between cancer cell lines and a normal cell line

DEFF Research Database (Denmark)

Frandsen, Stine Krog; McNeil, Anna K.; Novak, Ivana

2016-01-01

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...... cancer cell lines (p immortalized cell line (p

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.

Frequency of intrachromosomal homologous recombination induced by UV radiation in normally repairing and excision repair-deficient human cells

International Nuclear Information System (INIS)

Tsujimura, T.; Maher, V.M.; McCormick, J.J.; Godwin, A.R.; Liskay, R.M.

1990-01-01

To investigate the role of DNA damage and nucleotide excision repair in intrachromosomal homologous recombination, a plasmid containing duplicated copies of the gene coding for hygromycin resistance was introduced into the genome of a repair-proficient human cell line, KMST-6, and two repair-deficient lines, XP2OS(SV) from xeroderma pigmentosum complementation group A and XP2YO(SV) from complementation group F. Neither hygromycin-resistance gene codes for a functional enzyme because each contains an insertion/deletion mutation at a unique site, but recombination between the two defective genes can yield hygromycin-resistant cells. The rates of spontaneous recombination in normal and xeroderma pigmentosum cell strains containing the recombination substrate were found to be similar. The frequency of UV-induced recombination was determined for three of these cell strains. At low doses, the group A cell strain and the group F cell strain showed a significant increase in frequency of recombinants. The repair-proficient cell strain required 10-to 20-fold higher doses of UV to exhibit comparable increases in frequency of recombinants. These results suggest that unexcised DNA damage, rather than the excision repair process per se, stimulates such recombination

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

International Nuclear Information System (INIS)

Marie, Melanie; Hafner, Sophie; Moratille, Sandra; Vaigot, Pierre; Rigaud, Odile; Martin, Michele T.; Mine, Solene

2012-01-01

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)

Perspectives on stem cell therapy for cardiac regeneration. Advances and challenges.

Science.gov (United States)

Choi, Sung Hyun; Jung, Seok Yun; Kwon, Sang-Mo; Baek, Sang Hong

2012-01-01

Ischemic heart disease (IHD) accelerates cardiomyocyte loss, but the developing stem cell research could be useful for regenerating a variety of tissue cells, including cardiomyocytes. Diverse sources of stem cells for IHD have been reported, including embryonic stem cells, induced pluripotent stem cells, skeletal myoblasts, bone marrow-derived stem cells, mesenchymal stem cells, and cardiac stem cells. However, stem cells have unique advantages and disadvantages for cardiac tissue regeneration, which are important considerations in determining the specific cells for improving cell survival and long-term engraftment after transplantation. Additionally, the dosage and administration method of stem cells need to be standardized to increase stability and efficacy for clinical applications. Accordingly, this review presents a summary of the stem cell therapies that have been studied for cardiac regeneration thus far, and discusses the direction of future cardiac regeneration research for stem cells.

Relationship of DNA repair and chromosome aberrations to potentially lethal damage repair in X-irradiated mammalian cells

International Nuclear Information System (INIS)

Fornace, A.J. Jr.; Nagasawa, H.; Little, J.B.

1980-01-01

By the alkaline elution technique, the repair of x-ray-induced DNA single strand breaks and DNA-protein cross-links was investigated in stationary phase, contact-inhibited mouse cells. During the first hour of repair, approximately 90% of x-ray induced single strand breaks were rejoined whereas most of the remaining breaks were rejoined more slowly during the next 5 h. The number of residual non-rejoined single strand breaks was approximately proportional to the x-ray dose at early repair times. DNA-protein cross-links were removed at a slower rate - T 1/2 approximately 10 to 12 h. Cells were subcultured at low density at various times after irradiation and scored for colony survival, and chromosome aberrations in the first mitosis after sub-culture. Both cell lethality and the frequency of chromosome aberrations decreased during the first several hours of repair, reaching a minimum level by 6 h; this decrease correlated temporally with the repair of the slowly rejoining DNA strand breaks. The possible relationship of DNA repair to changes in survival and chromosome aberrations is discussed

X-ray repair replication in L1210 leukemia cells

International Nuclear Information System (INIS)

Lee, Y.C.; Byfield, J.E.; Bennett, L.R.; Chan, P.Y.M.

1974-01-01

Repair replication has been studied in detail in mouse L1210 leukemia cells. A method of identifying and quantitating repair replication using a pre- and postradiation block of normal replication with cytosine arabinoside is illustrated. The method derived does not require isolation of DNA per se and appears to be satisfactory for screening for inhibitors of repair replication. Repair replication can be demonstrated at doses in the 1000-rad range in bromouridine deoxyriboside-substituted cells and at slightly higher doses in nonsubstituted cells. Drugs that are known to bind to DNA inhibit this x-ray-induced repair replication. Drugs with these properties may be identified by the methods described and compared quantitatively in their ability to inhibit this type of x-ray damage. Since these phenomena can be demonstrated for low radiation doses and at drug concentrations attainable in vivo during human cancer chemotherapy this class of anticancer agent may be worthy of closer study. Application to the L1210 leukemia system should permit comparison of in vitro and in vivo drug effects in the context of the extensive in vivo pharmacological data already available for L1210 cells. (U.S.)

The Bright and the Dark Sides of DNA Repair in Stem Cells

OpenAIRE

Frosina, Guido

2010-01-01

DNA repair is a double-edged sword in stem cells. It protects normal stem cells in both embryonic and adult tissues from genetic damage, thus allowing perpetuation of intact genomes into new tissues. Fast and efficient DNA repair mechanisms have evolved in normal stem and progenitor cells. Upon differentiation, a certain degree of somatic mutations becomes more acceptable and, consequently, DNA repair dims. DNA repair turns into a problem when stem cells transform and become cancerous. Tran...

Patient-Specific Induced Pluripotent Stem Cell Models: Generation and Characterization of Cardiac Cells.

Science.gov (United States)

Zanella, Fabian; Sheikh, Farah

2016-01-01

The generation of human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes has been of utmost interest for the study of cardiac development, cardiac disease modeling, and evaluation of cardiotoxic effects of novel candidate drugs. Several protocols have been developed to guide human stem cells toward the cardiogenic path. Pioneering work used serum to promote cardiogenesis; however, low cardiogenic throughputs, lack of chemical definition, and batch-to-batch variability of serum lots constituted a considerable impediment to the implementation of those protocols to large-scale cell biology. Further work focused on the manipulation of pathways that mouse genetics indicated to be fundamental in cardiac development to promote cardiac differentiation in stem cells. Although extremely elegant, those serum-free protocols involved the use of human recombinant cytokines that tend to be quite costly and which can also be variable between lots. The latest generation of cardiogenic protocols aimed for a more cost-effective and reproducible definition of the conditions driving cardiac differentiation, using small molecules to manipulate cardiogenic pathways overriding the need for cytokines. This chapter details methods based on currently available cardiac differentiation protocols for the generation and characterization of robust numbers of hiPSC-derived cardiomyocytes under chemically defined conditions.

The repair of damage to DNA in different cell types

International Nuclear Information System (INIS)

Karran, P.

1974-01-01

DNA single strand breaks induced by either X-ray irradiation or by methyl methanesulphonate (MMS) were studied in different lymphoid cell populations directly taken from the animal and maintained in tissue culture merely for the duration of the experiment. The results obtained from these cell populations were compared with those obtained with L5178Y cells maintained in tissue culture. All cell types studied were found to possess at least one class of enzymes required for repair of DNA damage, namely those enzymes involved in the rejoining of X-ray induced by MMS is different in each cell type. Repair replication was at much reduced levels and the endonucleolytic degradation was at much reduced levels and the endonucleolytic degradation was initiated at lower MMS concentration in the lymphoid cells as compared to L5178Y cells. It is suggested that the overall ''repair capacity'' of a population may be related to the number of cells in a cycle which, moreover, might be the only ones to have the ability to repair damage to DNA induced by MMS (G.G.)

Increased DNA-repair in spleen cells of M. Hodgkin

International Nuclear Information System (INIS)

Frischauf, H.; Neumann, E.; Howanietz, L.; Dolejs, I.; Tuschl, H.; Altmann, H.

1974-11-01

In spleen cells of control patients and cells of Morbus Hodgkin, DNA-repair after gamma- and UV-irradiation was determined measuring the incorporated 3H-thymidine activity in the DNA. Additionally, the ratio of labeled cells compared to non-labeled cells and the grains per cell were evaluated by autoradiographic investigations. DNA-content per cell was measured using pulsecytophotometry. A significant increase of DNA-repair capacity after gamma-irradiation was found by density gradient centrifugation in alkaline sucrose. The same trend could be shown by investigations of unscheduled DNA-synthesis using autoradiographic method. (author)

Deficient repair of chemical adducts in alpha DNA of monkey cells

International Nuclear Information System (INIS)

Zolan, M.E.; Cortopassi, G.A.; Smith, C.A.; Hanawalt, P.C.

1982-01-01

Researchers have examined excision repair of DNA damage in the highly repeated alpha DNA sequence of cultured African green monkey cells. Irradiation of cells with 254 nm ultraviolet light resulted in the same frequency of pyrimidine dimers in alpha DNA and the bulk of the DNA. The rate and extent of pyrimidine dimer removal, as judged by measurement of repair synthesis, was also similar for alpha DNA and bulk DNA. In cells treated with furocoumarins and long-wave-length ultraviolet light, however, repair synthesis in alpha DNA was only 30% of that in bulk DNA, although it followed the same time course. Researchers found that this reduced repair was not caused by different initial amounts of furocoumarin damage or by different sizes of repair patches, as researchers found these to be similar in the two DNA species. Direct quantification demonstrated that fewer furocoumarin adducts were removed from alpha DNA than from bulk DNA. In cells treated with another chemical DNA-damaging agent, N-acetoxy-2-acetylaminofluorene, repair synthesis in alpha DNA was 60% of that in bulk DNA. These results show that the repair of different kinds of DNA damage can be affected to different extents by some property of this tandemly repeated heterochromatic DNA. To our knowledge, this is the first demonstration in primate cells of differential repair of cellular DNA sequences

Cardiac glycosides induce cell death in human cells by inhibiting general protein synthesis.

Directory of Open Access Journals (Sweden)

Andrea Perne

2009-12-01

Full Text Available Cardiac glycosides are Na(+/K(+-pump inhibitors widely used to treat heart failure. They are also highly cytotoxic, and studies have suggested specific anti-tumor activity leading to current clinical trials in cancer patients. However, a definitive demonstration of this putative anti-cancer activity and the underlying molecular mechanism has remained elusive.Using an unbiased transcriptomics approach, we found that cardiac glycosides inhibit general protein synthesis. Protein synthesis inhibition and cytotoxicity were not specific for cancer cells as they were observed in both primary and cancer cell lines. These effects were dependent on the Na(+/K(+-pump as they were rescued by expression of a cardiac glycoside-resistant Na(+/K(+-pump. Unlike human cells, rodent cells are largely resistant to cardiac glycosides in vitro and mice were found to tolerate extremely high levels.The physiological difference between human and mouse explains the previously observed sensitivity of human cancer cells in mouse xenograft experiments. Thus, published mouse xenograft models used to support anti-tumor activity for these drugs require reevaluation. Our finding that cardiac glycosides inhibit protein synthesis provides a mechanism for the cytotoxicity of CGs and raises concerns about ongoing clinical trials to test CGs as anti-cancer agents in humans.

Characterization of a mutant rat kangaroo cell line with alterations in the cell cycle and DNA repair

Directory of Open Access Journals (Sweden)

Miyaji E.N.

2000-01-01

Full Text Available Using a positive selection system for isolating DNA replication and repair related mutants, we isolated a clone from a rat kangaroo cell line (PtK2 that has increased sensitivity to UV light. Characterization of this clone indicated normal post-replication repair after UV irradiation, and normal removal rates of cyclobutane pyrimidine dimers and pyrimidine(6-4pyrimidone photoproducts by excision repair. However, this cell line has decreased ability to make early incisions on damaged DNA, possibly indicating a defect in preferential repair of actively transcribed genes, and a slower cell proliferation rate, including a longer S-phase. This phenotype reinforces the present notion that control of key mechanisms in cell metabolism, such as cell cycle control, repair, transcription and cell death, can be linked.

Repair of potentially lethal and sublethal radiation damage in x-irradiated ascites tumor cells

International Nuclear Information System (INIS)

Tsuboi, Atsushi; Okamoto, Mieko; Tsuchiya, Takehiko.

1985-01-01

The ability of cells to repair cellular radiation damage during the growth of TMT-3 ascites tumor and the effect of host reaction on the repair ability were examined by using an in vitro assay of cell clonogenicity after in situ irradiation of tumor cells. In single-dose experiments, the repair of potentially lethal radiation damage (PLD) was observed in stationary phase cells (12-day tumor) of the unirradiated host, but not in exponential phase cells (3-day tumor) of the unirradiated host animals. However, if previously irradiated host animals were used, even the exponentially growing tumor cells showed repair of PLD. In two-dose experiments, the ability to repair sublethal radiation damage (SLD) in exponential phase tumor cells was less than that of stationary phase cells in the unirradiated host. In the pre-irradiated host, the extent of the repair in exponential phase cells was somewhat enhanced. These results suggest that irradiation of host animals might suppress a factor that inhibits repair, resulting in enhancement of the repair capability of tumor cells. (author)

Diffuse myocardial fibrosis following tetralogy of Fallot repair: a T1 mapping cardiac magnetic resonance study

Energy Technology Data Exchange (ETDEWEB)

Kozak, Marcelo F.; Yoo, Shi-Joon; Seed, Mike; Grosse-Wortmann, Lars [The Hospital for Sick Children, University of Toronto, Labatt Family Heart Centre in the Department of Paediatrics and Department of Diagnostic Imaging, Toronto (Canada); Redington, Andrew [The Hospital for Sick Children, University of Toronto, Labatt Family Heart Centre in the Department of Paediatrics, Toronto (Canada); Greiser, Andreas [Siemens AG Healthcare Sector, Erlangen (Germany)

2014-04-15

Adverse ventricular remodeling after tetralogy of Fallot (TOF) repair is associated with diffuse myocardial fibrosis. The goal of this study was to measure post-contrast myocardial T1 in pediatric patients after TOF repair as surrogates of myocardial fibrosis. Children after TOF repair who underwent cardiac magnetic resonance imaging with T1 mapping using the modified look-locker inversion recovery (MOLLI) sequence were included. In addition to routine volumetric and flow data, we measured post-contrast T1 values of the basal interventricular septum, the left ventricular (LV) lateral wall, and the inferior and anterior walls of the right ventricle (RV). Results were compared to data from age-matched healthy controls. The scans of 18 children who had undergone TOF repair and 12 healthy children were included. Post-contrast T1 values of the left ventricular lateral wall (443 ± 54 vs. 510 ± 77 ms, P = 0.0168) and of the right ventricular anterior wall (333 ± 62 vs. 392 ± 72 ms, P = 0.0423) were significantly shorter in children with TOF repair than in controls, suggesting a higher degree of fibrosis. In children with TOF repair, but not in controls, post-contrast T1 values were shorter in the right ventricle than the left ventricle and shorter in the anterior wall of the right ventricle than in the inferior segments. In the TOF group, post-contrast T1 values of the RV anterior wall correlated with the RV end-systolic volume indexed to body surface area (r = 0.54; r{sup 2} = 0.30; P = 0.0238). In children who underwent tetralogy of Fallot repair the myocardium of both ventricles appears to bear an abnormally high fibrosis burden. (orig.)

Diffuse myocardial fibrosis following tetralogy of Fallot repair: a T1 mapping cardiac magnetic resonance study

International Nuclear Information System (INIS)

Kozak, Marcelo F.; Yoo, Shi-Joon; Seed, Mike; Grosse-Wortmann, Lars; Redington, Andrew; Greiser, Andreas

2014-01-01

Adverse ventricular remodeling after tetralogy of Fallot (TOF) repair is associated with diffuse myocardial fibrosis. The goal of this study was to measure post-contrast myocardial T1 in pediatric patients after TOF repair as surrogates of myocardial fibrosis. Children after TOF repair who underwent cardiac magnetic resonance imaging with T1 mapping using the modified look-locker inversion recovery (MOLLI) sequence were included. In addition to routine volumetric and flow data, we measured post-contrast T1 values of the basal interventricular septum, the left ventricular (LV) lateral wall, and the inferior and anterior walls of the right ventricle (RV). Results were compared to data from age-matched healthy controls. The scans of 18 children who had undergone TOF repair and 12 healthy children were included. Post-contrast T1 values of the left ventricular lateral wall (443 ± 54 vs. 510 ± 77 ms, P = 0.0168) and of the right ventricular anterior wall (333 ± 62 vs. 392 ± 72 ms, P = 0.0423) were significantly shorter in children with TOF repair than in controls, suggesting a higher degree of fibrosis. In children with TOF repair, but not in controls, post-contrast T1 values were shorter in the right ventricle than the left ventricle and shorter in the anterior wall of the right ventricle than in the inferior segments. In the TOF group, post-contrast T1 values of the RV anterior wall correlated with the RV end-systolic volume indexed to body surface area (r = 0.54; r 2 = 0.30; P = 0.0238). In children who underwent tetralogy of Fallot repair the myocardium of both ventricles appears to bear an abnormally high fibrosis burden. (orig.)

Boosting the pentose phosphate pathway restores cardiac progenitor cell availability in diabetes.

Science.gov (United States)

Katare, Rajesh; Oikawa, Atsuhiko; Cesselli, Daniela; Beltrami, Antonio P; Avolio, Elisa; Muthukrishnan, Deepti; Munasinghe, Pujika Emani; Angelini, Gianni; Emanueli, Costanza; Madeddu, Paolo

2013-01-01

Diabetes impinges upon mechanisms of cardiovascular repair. However, the biochemical adaptation of cardiac stem cells to sustained hyperglycaemia remains largely unknown. Here, we investigate the molecular targets of high glucose-induced damage in cardiac progenitor cells (CPCs) from murine and human hearts and attempt safeguarding CPC viability and function through reactivation of the pentose phosphate pathway. Type-1 diabetes was induced by streptozotocin. CPC abundance was determined by flow cytometry. Proliferating CPCs were identified in situ by immunostaining for the proliferation marker Ki67. Diabetic hearts showed marked reduction in CPC abundance and proliferation when compared with controls. Moreover, Sca-1(pos) CPCs isolated from hearts of diabetic mice displayed reduced activity of key enzymes of the pentose phosphate pathway, glucose-6-phosphate dehydrogenase (G6PD), and transketolase, increased levels of superoxide and advanced glucose end-products (AGE), and inhibition of the Akt/Pim-1/Bcl-2 signalling pathway. Similarly, culture of murine CPCs or human CD105(pos) progenitor cells in high glucose inhibits the pentose phosphate and pro-survival signalling pathways, leading to the activation of apoptosis. In vivo and in vitro supplementation with benfotiamine reactivates the pentose phosphate pathway and rescues CPC availability and function. This benefit is abrogated by either G6PD silencing by small interfering RNA (siRNA) or Akt inhibition by dominant-negative Akt. We provide new evidence of the negative impact of diabetes and high glucose on mechanisms controlling CPC redox state and survival. Boosting the pentose phosphate pathway might represent a novel mechanistic target for protection of CPC integrity.

PlGF repairs myocardial ischemia through mechanisms of angiogenesis, cardioprotection and recruitment of myo-angiogenic competent marrow progenitors.

Directory of Open Access Journals (Sweden)

Hiroto Iwasaki

Full Text Available Despite preclinical success in regenerating and revascularizing the infarcted heart using angiogenic growth factors or bone marrow (BM cells, recent clinical trials have revealed less benefit from these therapies than expected.We explored the therapeutic potential of myocardial gene therapy of placental growth factor (PlGF, a VEGF-related angiogenic growth factor, with progenitor-mobilizing activity.Myocardial PlGF gene therapy improves cardiac performance after myocardial infarction, by inducing cardiac repair and reparative myoangiogenesis, via upregulation of paracrine anti-apoptotic and angiogenic factors. In addition, PlGF therapy stimulated Sca-1(+/Lin(- (SL BM progenitor proliferation, enhanced their mobilization into peripheral blood, and promoted their recruitment into the peri-infarct borders. Moreover, PlGF enhanced endothelial progenitor colony formation of BM-derived SL cells, and induced a phenotypic switch of BM-SL cells, recruited in the infarct, to the endothelial, smooth muscle and cardiomyocyte lineage.Such pleiotropic effects of PlGF on cardiac repair and regeneration offer novel opportunities in the treatment of ischemic heart disease.

Cardiac remodeling following percutaneous mitral valve repair - initial results assessed by cardiovascular magnetic resonance imaging

DEFF Research Database (Denmark)

Radunski, U K; Franzen, O; Barmeyer, A

2014-01-01

PURPOSE: Percutaneous mitral valve repair with the MitraClip device (Abbott Vascular, Redwood City, California, USA) is a novel therapeutic option in patients with mitral regurgitation. This study evaluated the feasibility of cardiac volume measurements by cardiovascular magnetic resonance imaging...... (CMR) to assess reverse myocardial remodeling in patients after MitraClip implantation. MATERIALS AND METHODS: 12 patients underwent CMR at baseline (BL) before and at 6 months follow-up (FU) after MitraClip implantation. Cine-CMR was performed in short- and long-axes for the assessment of left...... end-systolic (48 [42 - 80] vs. 51 [40 - 81] ml/m(2); p = 0.48), and LA (87 [55 - 124] vs. 92 [48 - 137] ml/m(2); p = 0.20) volume indices between BL and FU. CONCLUSION: CMR enables the assessment of cardiac volumes in patients after MitraClip implantation. Our CMR findings indicate that percutaneous...

Saturation of DNA repair in mammalian cells

Energy Technology Data Exchange (ETDEWEB)

Ahmed, F E; Setlow, R B

1979-01-01

Excision repair seems to reach a plateau in normal human cells at a 254 nm dose near 20 J/m/sup 2/. We measured excision repair in normal human fibroblasts up to 80 J/m/sup 2/. The four techniques used (unscheduled DNA synthesis, photolysis of BrdUrd incorporated during repair, loss of sites sensitive to a UV endonuclease from Micrococcus luteus, and loss of pyrimidine dimers from DNA) showed little difference between the two doses. Moreover, the loss of endonuclease sites in 24h following two 20 J/m/sup 2/ doses separated by 24h was similar to the loss observed following one dose. Hence, we concluded that the observed plateau in excision repair is real and does not represent some inhibitory process at high doses but a true saturation of one of the rate limiting steps in repair.

Engineering the heart: Evaluation of conductive nanomaterials for improving implant integration and cardiac function

Science.gov (United States)

Zhou, Jin; Chen, Jun; Sun, Hongyu; Qiu, Xiaozhong; Mou, Yongchao; Liu, Zhiqiang; Zhao, Yuwei; Li, Xia; Han, Yao; Duan, Cuimi; Tang, Rongyu; Wang, Chunlan; Zhong, Wen; Liu, Jie; Luo, Ying; (Mengqiu) Xing, Malcolm; Wang, Changyong

2014-01-01

Recently, carbon nanotubes together with other types of conductive materials have been used to enhance the viability and function of cardiomyocytes in vitro. Here we demonstrated a paradigm to construct ECTs for cardiac repair using conductive nanomaterials. Single walled carbon nanotubes (SWNTs) were incorporated into gelatin hydrogel scaffolds to construct three-dimensional ECTs. We found that SWNTs could provide cellular microenvironment in vitro favorable for cardiac contraction and the expression of electrochemical associated proteins. Upon implantation into the infarct hearts in rats, ECTs structurally integrated with the host myocardium, with different types of cells observed to mutually invade into implants and host tissues. The functional measurements showed that SWNTs were essential to improve the performance of ECTs in inhibiting pathological deterioration of myocardium. This work suggested that conductive nanomaterials hold therapeutic potential in engineering cardiac tissues to repair myocardial infarction. PMID:24429673

DNA repair ability of cultured cells derived from mouse embryos in comparison with human cells

International Nuclear Information System (INIS)

Yaki, T.

1982-01-01

DNA repair in mouse cells derived from embryos of 3 inbred strains were investigated in comparison with that in human cells. The levels of unscheduled DNA synthesis after UV irradiation appeared to change at different passages, but capacities of host-cell reactivation of UV-irradiated herpes simplex virus were always reduced to the same levels as those in xeroderma pigmentosum cells. This implied that mouse cells are reduced in excision-repair capacities and that the apparently high levels of unscheduled DNA synthesis at certain passages are not quantitatively related to high levels of cell survival. Essentially no differences in DNA repair were noted among 3 strains - BALB/c, C3H/He and C57BL/10. (orig.)

Cardiac tissue engineering and regeneration using cell-based therapy

Directory of Open Access Journals (Sweden)

Alrefai MT

2015-05-01

Full Text Available Mohammad T Alrefai,1–3 Divya Murali,4 Arghya Paul,4 Khalid M Ridwan,1,2 John M Connell,1,2 Dominique Shum-Tim1,2 1Division of Cardiac Surgery, 2Division of Surgical Research, McGill University Health Center, Montreal, QC, Canada; 3King Faisal Specialist Hospital and Research Center, Jeddah, Saudi Arabia; 4Department of Chemical and Petroleum Engineering, School of Engineering, University of Kansas, Lawrence, KS, USA Abstract: Stem cell therapy and tissue engineering represent a forefront of current research in the treatment of heart disease. With these technologies, advancements are being made into therapies for acute ischemic myocardial injury and chronic, otherwise nonreversible, myocardial failure. The current clinical management of cardiac ischemia deals with reestablishing perfusion to the heart but not dealing with the irreversible damage caused by the occlusion or stenosis of the supplying vessels. The applications of these new technologies are not yet fully established as part of the management of cardiac diseases but will become so in the near future. The discussion presented here reviews some of the pioneering works at this new frontier. Key results of allogeneic and autologous stem cell trials are presented, including the use of embryonic, bone marrow-derived, adipose-derived, and resident cardiac stem cells. Keywords: stem cells, cardiomyocytes, cardiac surgery, heart failure, myocardial ischemia, heart, scaffolds, organoids, cell sheet and tissue engineering

DNA replication and repair in Tilapia cells. 1. The effect of ultraviolet radiation

Energy Technology Data Exchange (ETDEWEB)

Yew, F.H.; Chang, L.M. (National Taiwan Univ., Taipei (China))

1984-12-01

The effect of ultraviolet radiation on a cell line established from the warm water fish Tilapia has been assessed by measuring the rate of DNA synthesis, excision repair, post-replication repair and cell survival. The cells tolerate ultraviolet radiation better than mammalian cells with respect to DNA synthesis, post-replication repair and cell survival. They are also efficient in excision repair, which in other fish cell lines has been found to be at a low level or absent. Their response to the inhibitors hydroxyurea and 1-..beta..-D-arabinofuranosylcytosine is less sensitive than that of other cell lines, yet the cells seem to have very small pools of DNA precursor.

Plasma Levels of High Sensitivity Cardiac Troponin T in Adults with Repaired Tetralogy of Fallot

Science.gov (United States)

Lai, Clare T. M.; Wong, Sophia J.; Ip, Janice J. K.; Wong, Wai-keung; Tsang, Kwong-cheong; Lam, Wendy W. M.; Cheung, Yiu-fai

2015-01-01

Detectable low circulating level of cardiac troponin T (cTnT) may reflect subclinical myocardial injury. We tested the hypothesis that circulating levels of hs-cTnT are altered in adults with repaired tetralogy of Fallot (TOF) and associated with ventricular volume load and function. Eighty-eight TOF patients and 48 controls were studied. Plasma hs-cTnT levels were determined using a highly sensitive assay (hs-cTnT). The right (RV) and left ventricular (LV) volumes and ejection fraction (EF) were measured using 3D echocardiography and, in 52 patients, cardiac magnetic resonance (CMR). The median (interquartile range) for male and female patients were 4.87 (3.83–6.62) ng/L and 3.11 (1.00–3.87) ng/L, respectively. Thirty percent of female but none of the male patients had increased hs-cTnT levels. Female patients with elevated hs-cTnT levels, compared to those without, had greater RV end-diastolic and end-systolic volumes and LV systolic dyssynchrony index (all p < 0.05). For patient cohort only, hs-cTnT levels correlated positively with CMR-derived RV end-diastolic volume and negatively with echocardiography-derived LV and RV EF (all p < 0.05). Multiple linear regression identified sex and RV EF as significant correlates of log-transformed hs-cTnT levels. Increased hs-cTnT levels occur in 30% of female patients after TOF repair, and are associated with greater RV volumes and worse RV EF. PMID:26360613

Repair and regeneration: opportunities for carcinogenesis from tissue stem cells

OpenAIRE

Perryman, Scott V; Sylvester, Karl G

2007-01-01

This review will discuss the mechanisms of repair and regeneration in various tissue types and how dysregulation of these mechaisms may lead to cancer. Normal homeostasis involves a careful balance between cell loss and cell renewal. Stem and progenitor cells perform these biologic processes as the functional units of regeneration during both tissue homeostasis and repair. The concept of tissue stem cells capable of giving rise to all differentiated cells within a given tissue led to the conc...

Scaffold Free Bio-orthogonal Assembly of 3-Dimensional Cardiac Tissue via Cell Surface Engineering

Science.gov (United States)

Rogozhnikov, Dmitry; O'Brien, Paul J.; Elahipanah, Sina; Yousaf, Muhammad N.

2016-12-01

There has been tremendous interest in constructing in vitro cardiac tissue for a range of fundamental studies of cardiac development and disease and as a commercial system to evaluate therapeutic drug discovery prioritization and toxicity. Although there has been progress towards studying 2-dimensional cardiac function in vitro, there remain challenging obstacles to generate rapid and efficient scaffold-free 3-dimensional multiple cell type co-culture cardiac tissue models. Herein, we develop a programmed rapid self-assembly strategy to induce specific and stable cell-cell contacts among multiple cell types found in heart tissue to generate 3D tissues through cell-surface engineering based on liposome delivery and fusion to display bio-orthogonal functional groups from cell membranes. We generate, for the first time, a scaffold free and stable self assembled 3 cell line co-culture 3D cardiac tissue model by assembling cardiomyocytes, endothelial cells and cardiac fibroblast cells via a rapid inter-cell click ligation process. We compare and analyze the function of the 3D cardiac tissue chips with 2D co-culture monolayers by assessing cardiac specific markers, electromechanical cell coupling, beating rates and evaluating drug toxicity.

Biomaterial property-controlled stem cell fates for cardiac regeneration

Directory of Open Access Journals (Sweden)

Yanyi Xu

2016-09-01

Full Text Available Myocardial infarction (MI affects more than 8 million people in the United States alone. Due to the insufficient regeneration capacity of the native myocardium, one widely studied approach is cardiac tissue engineering, in which cells are delivered with or without biomaterials and/or regulatory factors to fully regenerate the cardiac functions. Specifically, in vitro cardiac tissue engineering focuses on using biomaterials as a reservoir for cells to attach, as well as a carrier of various regulatory factors such as growth factors and peptides, providing high cell retention and a proper microenvironment for cells to migrate, grow and differentiate within the scaffolds before implantation. Many studies have shown that the full establishment of a functional cardiac tissue in vitro requires synergistic actions between the seeded cells, the tissue culture condition, and the biochemical and biophysical environment provided by the biomaterials-based scaffolds. Proper electrical stimulation and mechanical stretch during the in vitro culture can induce the ordered orientation and differentiation of the seeded cells. On the other hand, the various scaffolds biochemical and biophysical properties such as polymer composition, ligand concentration, biodegradability, scaffold topography and mechanical properties can also have a significant effect on the cellular processes.

Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

Directory of Open Access Journals (Sweden)

Jose Luis Ramirez-GarciaLuna

Full Text Available In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1 mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2 re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3 the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

Defective bone repair in mast cell-deficient Cpa3Cre/+ mice.

Science.gov (United States)

Ramirez-GarciaLuna, Jose Luis; Chan, Daniel; Samberg, Robert; Abou-Rjeili, Mira; Wong, Timothy H; Li, Ailian; Feyerabend, Thorsten B; Rodewald, Hans-Reimer; Henderson, Janet E; Martineau, Paul A

2017-01-01

In the adult skeleton, cells of the immune system interact with those of the skeleton during all phases of bone repair to influence the outcome. Mast cells are immune cells best known for their pathologic role in allergy, and may be involved in chronic inflammatory and fibrotic disorders. Potential roles for mast cells in tissue homeostasis, vascularization and repair remain enigmatic. Previous studies in combined mast cell- and Kit-deficient KitW-sh/W-sh mice (KitW-sh) implicated mast cells in bone repair but KitW-sh mice suffer from additional Kit-dependent hematopoietic and non- hematopoietic deficiencies that could have confounded the outcome. The goal of the current study was to compare bone repair in normal wild type (WT) and Cpa3Cre/+ mice, which lack mast cells in the absence of any other hematopoietic or non- hematopoietic deficiencies. Repair of a femoral window defect was characterized using micro CT imaging and histological analyses from the early inflammatory phase, through soft and hard callus formation, and finally the remodeling phase. The data indicate 1) mast cells appear in healing bone of WT mice but not Cpa3Cre/+ mice, beginning 14 days after surgery; 2) re-vascularization of repair tissue and deposition of mineralized bone was delayed and dis-organised in Cpa3Cre/+ mice compared with WT mice; 3) the defects in Cpa3Cre/+ mice were associated with little change in anabolic activity and biphasic alterations in osteoclast and macrophage activity. The outcome at 56 days postoperative was complete bridging of the defect in most WT mice and fibrous mal-union in most Cpa3Cre/+ mice. The results indicate that mast cells promote bone healing, possibly by recruiting vascular endothelial cells during the inflammatory phase and coordinating anabolic and catabolic activity during tissue remodeling. Taken together the data indicate that mast cells have a positive impact on bone repair.

In vitro epigenetic reprogramming of human cardiac mesenchymal stromal cells into functionally competent cardiovascular precursors.

Directory of Open Access Journals (Sweden)

Matteo Vecellio

Full Text Available Adult human cardiac mesenchymal-like stromal cells (CStC represent a relatively accessible cell type useful for therapy. In this light, their conversion into cardiovascular precursors represents a potential successful strategy for cardiac repair. The aim of the present work was to reprogram CStC into functionally competent cardiovascular precursors using epigenetically active small molecules. CStC were exposed to low serum (5% FBS in the presence of 5 µM all-trans Retinoic Acid (ATRA, 5 µM Phenyl Butyrate (PB, and 200 µM diethylenetriamine/nitric oxide (DETA/NO, to create a novel epigenetically active cocktail (EpiC. Upon treatment the expression of markers typical of cardiac resident stem cells such as c-Kit and MDR-1 were up-regulated, together with the expression of a number of cardiovascular-associated genes including KDR, GATA6, Nkx2.5, GATA4, HCN4, NaV1.5, and α-MHC. In addition, profiling analysis revealed that a significant number of microRNA involved in cardiomyocyte biology and cell differentiation/proliferation, including miR 133a, 210 and 34a, were up-regulated. Remarkably, almost 45% of EpiC-treated cells exhibited a TTX-sensitive sodium current and, to a lower extent in a few cells, also the pacemaker I(f current. Mechanistically, the exposure to EpiC treatment introduced global histone modifications, characterized by increased levels of H3K4Me3 and H4K16Ac, as well as reduced H4K20Me3 and H3s10P, a pattern compatible with reduced proliferation and chromatin relaxation. Consistently, ChIP experiments performed with H3K4me3 or H3s10P histone modifications revealed the presence of a specific EpiC-dependent pattern in c-Kit, MDR-1, and Nkx2.5 promoter regions, possibly contributing to their modified expression. Taken together, these data indicate that CStC may be epigenetically reprogrammed to acquire molecular and biological properties associated with competent cardiovascular precursors.

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

International Nuclear Information System (INIS)

Desai, Amar; Webb, Bryan; Gerson, Stanton L.

2014-01-01

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

Cardiac Ochronosis

Science.gov (United States)

Erek, Ersin; Casselman, Filip P.A.; Vanermen, Hugo

2004-01-01

We report the case of 67-year-old woman who underwent aortic valve replacement and mitral valve repair due to ochronotic valvular disease (alkaptonuria), which was diagnosed incidentally during cardiac surgery. PMID:15745303

DNA repair and its coupling to DNA replication in eukaryotic cells. [UV, x ray

Energy Technology Data Exchange (ETDEWEB)

Cleaver, J.E.

1978-01-01

This review article with 184 references presents the view that mammalian cells have one major repair system, excision repair, with many branches (nucleotide excision repair, base excision repair, crosslink repair, etc.) and a multiplicity of enzymes. Any particular carcinogen makes a spectrum of damaged sites and each kind of damage may be repaired by one or more branches of excision repair. Excision repair is rarely complete, except at very low doses, and eukaryotic cells survive and replicate DNA despite the presence of unrepaired damage. An alteration in a specific biochemical pathway seen in damaged or mutant cells will not always be the primary consequence of damage or of the biochemical defect of the cells. Detailed kinetic data are required to understand comprehensively the various facets of excision repair and replication. Correlation between molecular events of repair and cytological and cellular changes such as chromosomal damage, mutagenesis, transformation, and carcinogenesis are also rudimentary.

Noninvasive detection of cardiac repair after acute myocardial infarction in rats by 111In fab fragment of monoclonal antibody specific for tenascin-C

International Nuclear Information System (INIS)

Okada, Kenichi; Uehara, Tomoya; Arano, Yasushi

2008-01-01

Left ventricular (LV) remodeling after acute myocardial infarction (MI) causes heart failure, and thus it is important to evaluate cardiac repair as the early stage of LV remodeling. Tenascin-C (TNC), an extracellular matrix glycoprotein, is transiently and abundantly expressed in the heart during the early stage of tissue remodeling after MI. However, it is not expressed in healthy adult heart. This study was undertaken to develop a new noninvasive diagnostic technique to detect cardiac repair after acute MI using 111 In Fab fragment of a monoclonal antibody specific for TNC. 111 In-anti-TNC-Fab was injected intravenously in 13 rats at 1 (D1, n=3), 3 (D3, n=5), and 5 (D5, n=5) days after producing MI and in 5 sham-operated rats (S). We performed autoradiography and dual-isotope single-photon emission computed tomography imaging (SPECT) of 111 In-anti-TNC-Fab and 99m Tc methoxyisobutyl isonitrile (MIBI). The radioactivity in the heart was significantly higher in D (D1, 0.45±0.06% injected-dose/g; D3, 0.64±0.12; D5, 0.38±0.07) than S (0.27±0.06, P 111 In-anti-TNC-Fab, which was complementary to the perfusion image. The results of the present study indicated that we can localize the infarcted region in the heart by ex vivo and in vivo imaging methods using 111 In-anti-TNC-Fab, and suggested the potential usefulness of noninvasive detection of cardiac repair. (author)

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

International Nuclear Information System (INIS)

Gibson, R.E.; D'Ambrosio, S.M.; Ohio State Univ., Columbus

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. (author)

Roles of neural stem cells in the repair of peripheral nerve injury.

Science.gov (United States)

Wang, Chong; Lu, Chang-Feng; Peng, Jiang; Hu, Cheng-Dong; Wang, Yu

2017-12-01

Currently, researchers are using neural stem cell transplantation to promote regeneration after peripheral nerve injury, as neural stem cells play an important role in peripheral nerve injury repair. This article reviews recent research progress of the role of neural stem cells in the repair of peripheral nerve injury. Neural stem cells can not only differentiate into neurons, astrocytes and oligodendrocytes, but can also differentiate into Schwann-like cells, which promote neurite outgrowth around the injury. Transplanted neural stem cells can differentiate into motor neurons that innervate muscles and promote the recovery of neurological function. To promote the repair of peripheral nerve injury, neural stem cells secrete various neurotrophic factors, including brain-derived neurotrophic factor, fibroblast growth factor, nerve growth factor, insulin-like growth factor and hepatocyte growth factor. In addition, neural stem cells also promote regeneration of the axonal myelin sheath, angiogenesis, and immune regulation. It can be concluded that neural stem cells promote the repair of peripheral nerve injury through a variety of ways.

Induced Pluripotent Stem Cells-Derived Mesenchymal Stem Cells Attenuate Cigarette Smoke-Induced Cardiac Remodeling and Dysfunction

Directory of Open Access Journals (Sweden)

Yingmin Liang

2017-07-01

Full Text Available The strong relationship between cigarette smoking and cardiovascular disease (CVD has been well-documented, but the mechanisms by which smoking increases CVD risk appear to be multifactorial and incompletely understood. Mesenchymal stem cells (MSCs are regarded as an important candidate for cell-based therapy in CVD. We hypothesized that MSCs derived from induced pluripotent stem cell (iPSC-MSCs or bone marrow (BM-MSCs might alleviate cigarette smoke (CS-induced cardiac injury. This study aimed to investigate the effects of BM-MSCs or iPSC-MSCs on CS-induced changes in serum and cardiac lipid profiles, oxidative stress and inflammation as well as cardiac function in a rat model of passive smoking. Male Sprague-Dawley rats were randomly selected for exposure to either sham air (SA as control or 4% CS for 1 h per day for 56 days. On day 29 and 43, human adult BM-MSCs, iPSC-MSCs or PBS were administered intravenously to CS-exposed rats. Results from echocardiography, serum and cardiac lipid profiles, cardiac antioxidant capacity, cardiac pro- and anti-inflammatory cytokines and cardiac morphological changes were evaluated at the end of treatment. iPSC-MSC-treated group showed a greater effect in the improvement of CS-induced cardiac dysfunction over BM-MSCs-treated group as shown by increased percentage left ventricular ejection fraction and percentage fractional shortening, in line with the greater reversal of cardiac lipid abnormality. In addition, iPSC-MSCs administration attenuated CS-induced elevation of cardiac pro-inflammatory cytokines as well as restoration of anti-inflammatory cytokines and anti-oxidative markers, leading to ameliorate cardiac morphological abnormalities. These data suggest that iPSC-MSCs on one hand may restore CS-induced cardiac lipid abnormality and on the other hand may attenuate cardiac oxidative stress and inflammation via inhibition of CS-induced NF-κB activation, leading to improvement of cardiac remodeling and

Human-induced pluripotent stem cell-derived cardiomyocytes from cardiac progenitor cells: effects of selective ion channel blockade.

Science.gov (United States)

Altomare, Claudia; Pianezzi, Enea; Cervio, Elisabetta; Bolis, Sara; Biemmi, Vanessa; Benzoni, Patrizia; Camici, Giovanni G; Moccetti, Tiziano; Barile, Lucio; Vassalli, Giuseppe

2016-12-01

Human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes are likely to revolutionize electrophysiological approaches to arrhythmias. Recent evidence suggests the somatic cell origin of hiPSCs may influence their differentiation potential. Owing to their cardiomyogenic potential, cardiac-stromal progenitor cells (CPCs) are an interesting cellular source for generation of hiPSC-derived cardiomyocytes. The effect of ionic current blockade in hiPSC-derived cardiomyocytes generated from CPCs has not been characterized yet. Human-induced pluripotent stem cell-derived cardiomyocytes were generated from adult CPCs and skin fibroblasts from the same individuals. The effect of selective ionic current blockade on spontaneously beating hiPSC-derived cardiomyocytes was assessed using multi-electrode arrays. Cardiac-stromal progenitor cells could be reprogrammed into hiPSCs, then differentiated into hiPSC-derived cardiomyocytes. Human-induced pluripotent stem cell-derived cardiomyocytes of cardiac origin showed higher upregulation of cardiac-specific genes compared with those of fibroblastic origin. Human-induced pluripotent stem cell-derived cardiomyocytes of both somatic cell origins exhibited sensitivity to tetrodotoxin, a blocker of Na +  current (I Na ), nifedipine, a blocker of L-type Ca 2+  current (I CaL ), and E4031, a blocker of the rapid component of delayed rectifier K +  current (I Kr ). Human-induced pluripotent stem cell-derived cardiomyocytes of cardiac origin exhibited sensitivity to JNJ303, a blocker of the slow component of delayed rectifier K +  current (I Ks ). In hiPSC-derived cardiomyocytes of cardiac origin, I Na , I CaL , I Kr , and I Ks were present as tetrodotoxin-, nifedipine-, E4031-, and JNJ303-sensitive currents, respectively. Although cardiac differentiation efficiency was improved in hiPSCs of cardiac vs. non-cardiac origin, no major functional differences were observed between hiPSC-derived cardiomyocytes of different somatic

Ultrasound-guided transversus abdominis plane block in combination with ilioinguinal-iliohypogastric block in a high risk cardiac patient for inguinal hernia repair: a case report

OpenAIRE

BARISIN, STJEPAN; DUZEL, VIKTOR; SAKIC, LIVIJA

2015-01-01

Background and Purpose: A high risk cardiac patient, ASA IV, was planned for inguinal hernia repair. Since general anaesthesia presented a high risk, anaesthesia was conducted with a transversus abdominis plane (TAP) in combination with ilioinguinal-iliohypogastric (ILIH) block. Material and Methods: A 70-year old male patient with severe CAD and previous LAD PTCA, AVR, in situ PPM and severe MR and TR 3+, was planned for elective inguinal hernia repair. The preoperative ECH...

Quantitation of DNA repair in brain cell cultures: implications for autoradiographic analysis of mixed cell populations

International Nuclear Information System (INIS)

Dambergs, R.; Kidson, C.

1979-01-01

Quantitation of DNA repair in the mixed cell population of mouse embryo brain cultures has been assessed by autoradiographic analysis of unscheduled DNA synthesis following UV-irradiation. The proportion of labelled neurons and the grain density over neuronal nuclei were both less than the corresponding values for glial cells. The nuclear geometries of these two classes of cell are very different. Partial correction for the different geometries by relating grain density to nuclear area brought estimates of neuronal and glial DNA repair synthesis more closely in line. These findings have general implications for autoradiographic measurement of DNA repair in mixed cell populations and in differentiated versus dividing cells. (author)

Role of DNA lesions and repair in the transformation of human cells

International Nuclear Information System (INIS)

Maher, V.M.; McCormick, J.J.

1987-01-01

Results of studies on the transformation of diploid human fibroblasts in culture into tumor-forming cells by exposure to chemical carcinogens or radiation indicate that such transformation is multi-stepped process that at least one step, acquisition of anchorage independence, occurs as a mutagenic event. Studies comparing normal-repairing human cells with DNA repair-deficient cells, such as those derived from cancer-prone xeroderma pigmentosum patients, indicate that excision repair in human fibroblasts is essentially an error-free process that the ability to excise potentially cytotoxic, mutagenic, or transforming lesions induced DNA by carcinogens determines their ultimate biological consequences. Cells deficient in excision repair are abnormally sensitive to these agents. Studies with cells treated at various times in the cell cycle show that there is a certain limited amount of time available for DNA repair between the initial exposure and the onset of the cellular event responsible for mutation induction and transformation to anchorage independence. The data suggest that DNA replication on a template containing unexcised lesions (photoproducts, adducts) is the critical event

Cell Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath

Science.gov (United States)

2017-07-01

to subsequently guide tissue regeneration , for example, by seeded tissue progenitor cells . To achieve this objective, the first step is to develop...AWARD NUMBER: W81XWH-15-1-0104 TITLE: Cell -Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath PRINCIPAL INVESTIGATOR...SUBTITLE 5a. CONTRACT NUMBER Cell -Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath 5b. GRANT NUMBER W81XWH-15-1-0104 5c. PROGRAM

Exosomes from Cardiomyocyte Progenitor Cells and Mesenchymal Stem Cells Stimulate Angiogenesis Via EMMPRIN

NARCIS (Netherlands)

Vrijsen, Krijn R.; Maring, Janita A.; Chamuleau, Steven A J; Verhage, Vera; Mol, Emma A.; Deddens, Janine C.; Metz, Corina H G; Lodder, Kirsten; van Eeuwijk, Esther C M; van Dommelen, Susan M.; Doevendans, Pieter A.; Smits, Anke M.; Goumans, Marie José; Sluijter, Joost P G

2016-01-01

To date, cellular transplantation therapy has not yet fulfilled its high expectations for cardiac repair. A major limiting factor is lack of long-term engraftment of the transplanted cells. Interestingly, transplanted cells can positively affect their environment via secreted paracrine factors,

The stem cell secretome and its role in brain repair.

Science.gov (United States)

Drago, Denise; Cossetti, Chiara; Iraci, Nunzio; Gaude, Edoardo; Musco, Giovanna; Bachi, Angela; Pluchino, Stefano

2013-12-01

Compelling evidence exists that non-haematopoietic stem cells, including mesenchymal (MSCs) and neural/progenitor stem cells (NPCs), exert a substantial beneficial and therapeutic effect after transplantation in experimental central nervous system (CNS) disease models through the secretion of immune modulatory or neurotrophic paracrine factors. This paracrine hypothesis has inspired an alternative outlook on the use of stem cells in regenerative neurology. In this paradigm, significant repair of the injured brain may be achieved by injecting the biologics secreted by stem cells (secretome), rather than implanting stem cells themselves for direct cell replacement. The stem cell secretome (SCS) includes cytokines, chemokines and growth factors, and has gained increasing attention in recent years because of its multiple implications for the repair, restoration or regeneration of injured tissues. Thanks to recent improvements in SCS profiling and manipulation, investigators are now inspired to harness the SCS as a novel alternative therapeutic option that might ensure more efficient outcomes than current stem cell-based therapies for CNS repair. This review discusses the most recent identification of MSC- and NPC-secreted factors, including those that are trafficked within extracellular membrane vesicles (EVs), and reflects on their potential effects on brain repair. It also examines some of the most convincing advances in molecular profiling that have enabled mapping of the SCS. Copyright © 2013 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

Repair of human DNA: radiation and chemical damage in normal and xeroderma pigmentosum cells

International Nuclear Information System (INIS)

Regan, J.D.; Setlow, R.B.

1976-01-01

We present the experimental evidence we have gathered, using a particular assay for DNA repair in human cells, the photolysis of bromodeoxyuridine (BrdUrd) incorporated during repair. This assay characterizes the sequence of repair events that occur in human cells after radiation, both ultraviolet and ionizing, and permits an estimation of the size of the average repaired region after these physical insults to DNA. We will discuss chemical insults to DNA and attempt to liken the repair processes after chemical damages of various kinds to those repair processes that occur in human DNA after damage from physical agents. We will also show results indicating that, under certain conditions, repair events resembling those seen after uv-irradiation can be observed in normal human cells after ionizing radiation. Furthermore the XP cells, defective in the repair of uv-induced DNA damage, show defective repair of these uv-like DNA lesions induced by ionizing radiation

DNA repair in human cells exposed to combinations of carcinogenic agents

International Nuclear Information System (INIS)

Setlow, R.B.; Ahmed, F.E.

1980-01-01

Normal human and XP 2 fibroblasts were treated with uv plus uv-mimetic chemicals. The uv dose used was sufficient to saturate the uv excision repair system. Excision repair after combined treatments was estimated by unscheduled DNA synthesis, BrdUrd photolysis, and the loss of sites sensitive to a uv specific endonuclease. Since the repair of damage from uv and its mimetics is coordinately controlled we expected that there would be similar rate-limiting steps in the repair of uv and chemical damage and that after a combined treatment the total amount of repair would be the same as from uv or the chemicals separately. The expectation was not fulfilled. In normal cells repair after a combined treatment was additive whereas in XP cells repair after a combined treatment was usually less than after either agent separately. The chemicals tested were AAAF, DMBA-epoxide, 4NQO, and ICR-170

STAT3 Controls the Long-Term Survival and Phenotype of Repair Schwann Cells during Nerve Regeneration.

Science.gov (United States)

Benito, Cristina; Davis, Catherine M; Gomez-Sanchez, Jose A; Turmaine, Mark; Meijer, Dies; Poli, Valeria; Mirsky, Rhona; Jessen, Kristjan R

2017-04-19

After nerve injury, Schwann cells convert to a phenotype specialized to promote repair. But during the slow process of axonal regrowth, these repair Schwann cells gradually lose their regeneration-supportive features and eventually die. Although this is a key reason for the frequent regeneration failures in humans, the transcriptional mechanisms that control long-term survival and phenotype of repair cells have not been studied, and the molecular signaling underlying their decline is obscure. We show, in mice, that Schwann cell STAT3 has a dual role. It supports the long-term survival of repair Schwann cells and is required for the maintenance of repair Schwann cell properties. In contrast, STAT3 is less important for the initial generation of repair Schwann cells after injury. In repair Schwann cells, we find that Schwann cell STAT3 activation by Tyr705 phosphorylation is sustained during long-term denervation. STAT3 is required for maintaining autocrine Schwann cell survival signaling, and inactivation of Schwann cell STAT3 results in a striking loss of repair cells from chronically denervated distal stumps. STAT3 inactivation also results in abnormal morphology of repair cells and regeneration tracks, and failure to sustain expression of repair cell markers, including Shh, GDNF, and BDNF. Because Schwann cell development proceeds normally without STAT3, the function of this factor appears restricted to Schwann cells after injury. This identification of transcriptional mechanisms that support long-term survival and differentiation of repair cells will help identify, and eventually correct, the failures that lead to the deterioration of this important cell population. SIGNIFICANCE STATEMENT Although injured peripheral nerves contain repair Schwann cells that provide signals and spatial clues for promoting regeneration, the clinical outcome after nerve damage is frequently poor. A key reason for this is that, during the slow growth of axons through the proximal

DNA replication and post-replication repair in U.V.-sensitive mouse neuroblastoma cells

International Nuclear Information System (INIS)

Lavin, M.F.; McCombe, P.; Kidson, C.

1976-01-01

Mouse neuroblastoma cells differentiated when grown in the absence of serum; differentiation was reversed on the addition of serum. Differentiated cells were more sensitive to U.V.-radiation than proliferating cells. Whereas addition of serum to differentiated neuroblastoma cells normally resulted in immediate, synchronous entry into S phase, irradiation just before the addition of serum resulted in a long delay in the onset of DNA replication. During this lag period, incorporated 3 H-thymidine appeared in the light density region of CsCl gradients, reflecting either repair synthesis or abortive replication. Post-replication repair (gap-filling) was found to be present in proliferating cells and at certain times in differentiated cells. It is suggested that the sensitivity of differentiated neuroblastoma cells to U.V.-radiation may have been due to ineffective post-replication repair or to deficiencies in more than one repair mechanism, with reduction in repair capacity beyond a critical threshold. (author)

Radiation studies on sensitivity and repair of human mammary epithelial cells

International Nuclear Information System (INIS)

Tracy Chuihsu Yang; Stampfer, M.R.; Tobias, C.A.

1989-01-01

The authors present results indicating that normal breast epithelial cells and fibroblasts respond to X-rays similarly, lacking significant repair of sublethal damage when 2 Gy was used as the conditioning dose. Epithelial cells from tumor and from parenchymal tissue peripheral to the tumor, however, did show an efficient repair of sublethal damage. The reasons for this difference is unknown. Heavy-ion studies suggest energetic carbon and neon particles can be more effective in killing normal and tumour cells. The RBE for normal cells, however, appeared to be slightly less than for tumor cells. The repair of sublethal damage in tumor cells was less for neon particles than for X-rays. These findings suggest that heavy ions might be more advantageous than X-rays in treating breast tumors. (author)

Some important advances in DNA repair study on the mammalian cells

International Nuclear Information System (INIS)

Xia Shouxuan.

1991-01-01

In the recent years the study of DNA damage and repair in the mammalian cells has gone deeply at gene level and got the following advances: (1) For a long time DNA has been considered to be an uniform unit in case of damage and repair. Now this concept should be replaced by the non-random distribution of damage and heterogenous repair in the genome. These would allow us to study cellular mutagenesis, carcinogenesis, aging and dying processes in great detail, and would be beneficial to the elucidation of mechanisms of radiation sickness and chemical toxicology. (2) The advent of new techniques in molecular biology has made it possible to isolate and clone the human DNA repair genes. Up to now more than ten human DNA repair genes have been cloned and these works would have an important impact on the theoretical and practical study in this field. Because DNA repair system is very complicate, voluminous work should be done in the future. (3) The technique of gene transfer has been efficiently used in the study of DNA repair in mammalian cells and has made great contribution in the cellular engineering. It could modify the genetic behavior of the gene-accepting cells, and enhance the DNA repair ability to physical and chemical damages. Human gene therapy for DNA deficient diseases is now on the day

Pathologic Stimulus Determines Lineage Commitment of Cardiac C-kit+ Cells.

Science.gov (United States)

Chen, Zhongming; Zhu, Wuqiang; Bender, Ingrid; Gong, Wuming; Kwak, Il-Youp; Yellamilli, Amritha; Hodges, Thomas J; Nemoto, Natsumi; Zhang, Jianyi; Garry, Daniel J; van Berlo, Jop H

2017-12-12

Although cardiac c-kit + cells are being tested in clinical trials, the circumstances that determine lineage differentiation of c-kit + cells in vivo are unknown. Recent findings suggest that endogenous cardiac c-kit + cells rarely contribute cardiomyocytes to the adult heart. We assessed whether various pathological stimuli differentially affect the eventual cell fates of c-kit + cells. We used single-cell sequencing and genetic lineage tracing of c-kit + cells to determine whether various pathological stimuli would result in different fates of c-kit + cells. Single-cell sequencing of cardiac CD45 - c-kit + cells showed innate heterogeneity, indicative of the existence of vascular and mesenchymal c-kit + cells in normal hearts. Cardiac pressure overload resulted in a modest increase in c-kit-derived cardiomyocytes, with significant increases in the numbers of endothelial cells and fibroblasts. Doxorubicin-induced acute cardiotoxicity did not increase c-kit-derived endothelial cell fates but instead induced cardiomyocyte differentiation. Mechanistically, doxorubicin-induced DNA damage in c-kit + cells resulted in expression of p53. Inhibition of p53 blocked cardiomyocyte differentiation in response to doxorubicin, whereas stabilization of p53 was sufficient to increase c-kit-derived cardiomyocyte differentiation. These results demonstrate that different pathological stimuli induce different cell fates of c-kit + cells in vivo. Although the overall rate of cardiomyocyte formation from c-kit + cells is still below clinically relevant levels, we show that p53 is central to the ability of c-kit + cells to adopt cardiomyocyte fates, which could lead to the development of strategies to preferentially generate cardiomyocytes from c-kit + cells. © 2017 American Heart Association, Inc.

Mechanisms of DNA damage repair in adult stem cells and implications for cancer formation.

Science.gov (United States)

Weeden, Clare E; Asselin-Labat, Marie-Liesse

2018-01-01

Maintenance of genomic integrity in tissue-specific stem cells is critical for tissue homeostasis and the prevention of deleterious diseases such as cancer. Stem cells are subject to DNA damage induced by endogenous replication mishaps or exposure to exogenous agents. The type of DNA lesion and the cell cycle stage will invoke different DNA repair mechanisms depending on the intrinsic DNA repair machinery of a cell. Inappropriate DNA repair in stem cells can lead to cell death, or to the formation and accumulation of genetic alterations that can be transmitted to daughter cells and so is linked to cancer formation. DNA mutational signatures that are associated with DNA repair deficiencies or exposure to carcinogenic agents have been described in cancer. Here we review the most recent findings on DNA repair pathways activated in epithelial tissue stem and progenitor cells and their implications for cancer mutational signatures. We discuss how deep knowledge of early molecular events leading to carcinogenesis provides insights into DNA repair mechanisms operating in tumours and how these could be exploited therapeutically. Copyright © 2017 Elsevier B.V. All rights reserved.

Modern problems of DNA repair in mammalian cells and some unsettled questions

International Nuclear Information System (INIS)

Gaziev, A.I.

1978-01-01

A comparison of DNA repair process in the cells of mammals and E. coli revealed no principal differences in the enzymic mechanisms of DNA repair in the cells of higher and lower organisms. It has been found that when given is the same number of impairments in the section of DNA chain in the cells of mammals and bacteria the regeneration in the former occurs more slowly than in the latter. Low rate elimination of impairments of DNA in the cells of mammals is due to a more complex intracellular and permolecular organization. It is stressed that the investigation into the mechanisms of fixing impairments in case of postreplication DNA repair is a very important and unresolved problem, especially in terms of radiation mutagenesis and cancerogenesis. Much thought is given to the problem of repairing double stranded ruptures of DNA. It is proposed that DNA repair should be considered not only in terms of functioning of enzymes in DNA metabolism, but also permolecular organization of genome in the cell

Sca-1+ cardiosphere-derived cells are enriched for Isl1-expressing cardiac precursors and improve cardiac function after myocardial injury.

Directory of Open Access Journals (Sweden)

Jianqin Ye

Full Text Available BACKGROUND: Endogenous cardiac progenitor cells are a promising option for cell-therapy for myocardial infarction (MI. However, obtaining adequate numbers of cardiac progenitors after MI remains a challenge. Cardiospheres (CSs have been proposed to have cardiac regenerative properties; however, their cellular composition and how they may be influenced by the tissue milieu remains unclear. METHODOLOGY/PRINCIPAL FINDING: Using "middle aged" mice as CSs donors, we found that acute MI induced a dramatic increase in the number of CSs in a mouse model of MI, and this increase was attenuated back to baseline over time. We also observed that CSs from post-MI hearts engrafted in ischemic myocardium induced angiogenesis and restored cardiac function. To determine the role of Sca-1(+CD45(- cells within CSs, we cloned these from single cell isolates. Expression of Islet-1 (Isl1 in Sca-1(+CD45(- cells from CSs was 3-fold higher than in whole CSs. Cloned Sca-1(+CD45(- cells had the ability to differentiate into cardiomyocytes, endothelial cells and smooth muscle cells in vitro. We also observed that cloned cells engrafted in ischemic myocardium induced angiogenesis, differentiated into endothelial and smooth muscle cells and improved cardiac function in post-MI hearts. CONCLUSIONS/SIGNIFICANCE: These studies demonstrate that cloned Sca-1(+CD45(- cells derived from CSs from infarcted "middle aged" hearts are enriched for second heart field (i.e., Isl-1(+ precursors that give rise to both myocardial and vascular tissues, and may be an appropriate source of progenitor cells for autologous cell-therapy post-MI.

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

Directory of Open Access Journals (Sweden)

Musah Sadiatu

2012-11-01

Full Text Available Abstract Background Chlorine is a widely used toxic compound that is considered a chemical threat agent. Chlorine inhalation injures airway epithelial cells, leading to pulmonary abnormalities. Efficient repair of injured epithelium is necessary to restore normal lung structure and function. The objective of the current study was to characterize repair of the tracheal epithelium after acute chlorine injury. Methods C57BL/6 mice were exposed to chlorine and injected with 5-ethynyl-2′-deoxyuridine (EdU to label proliferating cells prior to sacrifice and collection of tracheas on days 2, 4, 7, and 10 after exposure. Airway repair and restoration of a differentiated epithelium were examined by co-localization of EdU labeling with markers for the three major tracheal epithelial cell types [keratin 5 (K5 and keratin 14 (K14 for basal cells, Clara cell secretory protein (CCSP for Clara cells, and acetylated tubulin (AcTub for ciliated cells]. Morphometric analysis was used to measure proliferation and restoration of a pseudostratified epithelium. Results Epithelial repair was fastest and most extensive in proximal trachea compared with middle and distal trachea. In unexposed mice, cell proliferation was minimal, all basal cells expressed K5, and K14-expressing basal cells were absent from most sections. Chlorine exposure resulted in the sloughing of Clara and ciliated cells from the tracheal epithelium. Two to four days after chlorine exposure, cell proliferation occurred in K5- and K14-expressing basal cells, and the number of K14 cells was dramatically increased. In the period of peak cell proliferation, few if any ciliated or Clara cells were detected in repairing trachea. Expression of ciliated and Clara cell markers was detected at later times (days 7–10, but cell proliferation was not detected in areas in which these differentiated markers were re-expressed. Fibrotic lesions were observed at days 7–10 primarily in distal trachea. Conclusion

Phytochemicals radiosensitize cancer cells by inhibiting DNA repair

International Nuclear Information System (INIS)

Singh, Rana P.

2017-01-01

Solid tumors are mostly treated with radiotherapy. Radiotherapy is toxic to normal tissues and also promote the invasiveness and radioresistance in cancer cells. The resistance against radiotherapy and adverse effects to normal cells reduce the overall therapeutic effects of the treatment. Radiosensitizing agents usually show limited success during clinical trials. Therefore, the search and development of new radiosensitizers showing selective response to only cancer cells is desirable. We analyzed the radiosensitizing effects including cell death effect of silibinin, a phytochemical on prostate cancer cells. Silibinin enhanced gamma radiation (2.5-10 Gy) induced inhibition in colony formation selectively in prostate cancer cells. In cell cycle progression, G2/M phase is the most sensitive phase for radiation-induced damage which was delayed by the compound treatment in radiation exposed cells. The lower concentrations of silibinin substantially enhanced radiation-induced apoptosis. A prolonged reactive oxygen species production was also observed in these treatments EGFR signaling pathway can contribute to radiation-induced pro-survival mechanisms and to the therapeutic resistance. Agent treatment reduced the IR-induced EGFR phosphorylation and consequently reversed the resistance mediating mechanisms within the cancer cell. Thus, inhibiting DNA repair in cancer cells would enhance therapeutic response of radiation in cancer cells. Silibinin affected the localization of EGFR and DNA-dependent protein kinase, the DNA-PK is known to be an important mediator of DSB repair in human cells, and showed increased number of pH2AX (ser139) foci, and thus indicating lower DNA repair in these cancer cells. This was also confirmed in the tumor xenograft study. Our findings suggest that a combination of silibinin with radiation could be an effective treatment of radioresistant human prostate cancer and warrants further investigation. (author)

Cardiac cell modelling: Observations from the heart of the cardiac physiome project

KAUST Repository

Fink, Martin; Niederer, Steven A.; Cherry, Elizabeth M.; Fenton, Flavio H.; Koivumä ki, Jussi T.; Seemann, Gunnar; Thul, Rü diger; Zhang, Henggui; Sachse, Frank B.; Beard, Dan; Crampin, Edmund J.; Smith, Nicolas P.

2011-01-01

In this manuscript we review the state of cardiac cell modelling in the context of international initiatives such as the IUPS Physiome and Virtual Physiological Human Projects, which aim to integrate computational models across scales and physics. In particular we focus on the relationship between experimental data and model parameterisation across a range of model types and cellular physiological systems. Finally, in the context of parameter identification and model reuse within the Cardiac Physiome, we suggest some future priority areas for this field. © 2010 Elsevier Ltd.

DNA strand breakage repair in ataxia telangiectasia fibroblast-like cells

Energy Technology Data Exchange (ETDEWEB)

Vincent, Jr, R A; Sheridan, III, R B; Huang, P C [Johns Hopkins Univ., Baltimore, Md. (USA). Dept. of Environmental and Biophysical Sciences

1975-12-01

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.

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

International Nuclear Information System (INIS)

Cleaver, J.E.

1982-01-01

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

[Surgical Repair for Blunt Cardiac Rupture].

Science.gov (United States)

Yashiki, Noriyoshi; Yachi, Tsuyoshi; Takahashi, Tomohiko

2017-07-01

Blunt cardiac injury is a life-threatening condition. We report 3 successful cases in which we performed surgery for blunt cardiac injury. Three individuals were injured, 2 in traffic accidents and the other being caught between a crane and a steel frame. Echocardiograms and computed tomography scans revealed pooling of bloody pericardial fluid in all 3 patients, who underwent emergency surgery. Two patients needed sutures to control persistent bleeding. Although a heart-lung machine was prepared at the start of surgery in all 3 cases, we did not need to use it for any patient. Thus, prior to performing such surgery, it is necessary to ascertain its need.

A cell-free scaffold-based cartilage repair provides improved function hyaline-like repair at one year.

Science.gov (United States)

Siclari, Alberto; Mascaro, Gennaro; Gentili, Chiara; Cancedda, Ranieri; Boux, Eugenio

2012-03-01

Bone marrow stimulation techniques in cartilage repair such as drilling are limited by the formation of fibrous to hyaline-like repair tissue. It has been suggested such techniques can be enhanced by covering the defect with scaffolds. We present an innovative approach using a polyglycolic acid (PGA)-hyaluronan scaffold with platelet-rich-plasma (PRP) in drilling. We asked whether (1) PRP immersed in a cell-free PGA-hyaluronan scaffold improves patient-reported 1-year outcomes for the Knee injury and Osteoarthritis Score (KOOS), and (2) implantation of the scaffold in combination with bone marrow stimulation leads to the formation of hyaline-like cartilage repair tissue. We reviewed 52 patients who had arthroscopic implantation of the PGA-hyaluronan scaffold immersed with PRP in articular cartilage defects of the knee pretreated with Pridie drilling. Patients were assessed by KOOS. At 9 months followup, histologic staining was performed in specimens obtained from five patients to assess the repair tissue quality. The KOOS subscores improved for pain (55 to 91), symptoms (57 to 88), activities of daily living (69 to 86), sports and recreation (36 to 70), and quality of life (38 to 73). The histologic evaluation showed a homogeneous hyaline-like cartilage repair tissue. The cell-free PGA-hyaluronan scaffold combined with PRP leads to cartilage repair and improved patient-reported outcomes (KOOS) during 12 months of followup. Histologic sections showed morphologic features of hyaline-like repair tissue. Long-term followup is needed to determine if the cartilage repair tissue is durable. Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Molecular and environmental cues in cardiac differentiation of mesenchymal stem cells

NARCIS (Netherlands)

Ramkisoensing, Arti Anushka

2014-01-01

In this thesis molecular and environmental cues in cardiac differentiation of mesenchymal stem cells were investigated. The main conclusions were that the cardiac differentiation potential of human mesenchymal stem cells negatively correlates with donor age. This in its own shows a negative

Cardiac-Restricted IGF-1Ea Overexpression Reduces the Early Accumulation of Inflammatory Myeloid Cells and Mediates Expression of Extracellular Matrix Remodelling Genes after Myocardial Infarction

Directory of Open Access Journals (Sweden)

Enrique Gallego-Colon

2015-01-01

Full Text Available Strategies to limit damage and improve repair after myocardial infarct remain a major therapeutic goal in cardiology. Our previous studies have shown that constitutive expression of a locally acting insulin-like growth factor-1 Ea (IGF-1Ea propeptide promotes functional restoration after cardiac injury associated with decreased scar formation. In the current study, we investigated the underlying molecular and cellular mechanisms behind the enhanced functional recovery. We observed improved cardiac function in mice overexpressing cardiac-specific IGF-1Ea as early as day 7 after myocardial infarction. Analysis of gene transcription revealed that supplemental IGF-1Ea regulated expression of key metalloproteinases (MMP-2 and MMP-9, their inhibitors (TIMP-1 and TIMP-2, and collagen types (Col 1α1 and Col 1α3 in the first week after injury. Infiltration of inflammatory cells, which direct the remodelling process, was also altered; in particular there was a notable reduction in inflammatory Ly6C+ monocytes at day 3 and an increase in anti-inflammatory CD206+ macrophages at day 7. Taken together, these results indicate that the IGF-1Ea transgene shifts the balance of innate immune cell populations early after infarction, favouring a reduction in inflammatory myeloid cells. This correlates with reduced extracellular matrix remodelling and changes in collagen composition that may confer enhanced scar elasticity and improved cardiac function.

Ku80-deleted cells are defective at base excision repair

International Nuclear Information System (INIS)

Li, Han; Marple, Teresa; Hasty, Paul

2013-01-01

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 2 O 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

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.

Establishing Early Functional Perfusion and Structure in Tissue Engineered Cardiac Constructs.

Science.gov (United States)

Wang, Bo; Patnaik, Sourav S; Brazile, Bryn; Butler, J Ryan; Claude, Andrew; Zhang, Ge; Guan, Jianjun; Hong, Yi; Liao, Jun

2015-01-01

Myocardial infarction (MI) causes massive heart muscle death and remains a leading cause of death in the world. Cardiac tissue engineering aims to replace the infarcted tissues with functional engineered heart muscles or revitalize the infarcted heart by delivering cells, bioactive factors, and/or biomaterials. One major challenge of cardiac tissue engineering and regeneration is the establishment of functional perfusion and structure to achieve timely angiogenesis and effective vascularization, which are essential to the survival of thick implants and the integration of repaired tissue with host heart. In this paper, we review four major approaches to promoting angiogenesis and vascularization in cardiac tissue engineering and regeneration: delivery of pro-angiogenic factors/molecules, direct cell implantation/cell sheet grafting, fabrication of prevascularized cardiac constructs, and the use of bioreactors to promote angiogenesis and vascularization. We further provide a detailed review and discussion on the early perfusion design in nature-derived biomaterials, synthetic biodegradable polymers, tissue-derived acellular scaffolds/whole hearts, and hydrogel derived from extracellular matrix. A better understanding of the current approaches and their advantages, limitations, and hurdles could be useful for developing better materials for future clinical applications.

Restrictive or Liberal Red-Cell Transfusion for Cardiac Surgery

DEFF Research Database (Denmark)

Mazer, C David; Whitlock, Richard P; Fergusson, Dean A

2017-01-01

BACKGROUND: The effect of a restrictive versus liberal red-cell transfusion strategy on clinical outcomes in patients undergoing cardiac surgery remains unclear. METHODS: In this multicenter, open-label, noninferiority trial, we randomly assigned 5243 adults undergoing cardiac surgery who had a E...

Biochemistry and biology: heart-to-heart to investigate cardiac progenitor cells.

Science.gov (United States)

Chimenti, Isotta; Forte, Elvira; Angelini, Francesco; Messina, Elisa; Giacomello, Alessandro

2013-02-01

Cardiac regenerative medicine is a rapidly evolving field, with promising future developments for effective personalized treatments. Several stem/progenitor cells are candidates for cardiac cell therapy, and emerging evidence suggests how multiple metabolic and biochemical pathways strictly regulate their fate and renewal. In this review, we will explore a selection of areas of common interest for biology and biochemistry concerning stem/progenitor cells, and in particular cardiac progenitor cells. Numerous regulatory mechanisms have been identified that link stem cell signaling and functions to the modulation of metabolic pathways, and vice versa. Pharmacological treatments and culture requirements may be exploited to modulate stem cell pluripotency and self-renewal, possibly boosting their regenerative potential for cell therapy. Mitochondria and their many related metabolites and messengers, such as oxygen, ROS, calcium and glucose, have a crucial role in regulating stem cell fate and the balance of their functions, together with many metabolic enzymes. Furthermore, protein biochemistry and proteomics can provide precious clues on the definition of different progenitor cell populations, their physiology and their autocrine/paracrine regulatory/signaling networks. Interdisciplinary approaches between biology and biochemistry can provide productive insights on stem/progenitor cells, allowing the development of novel strategies and protocols for effective cardiac cell therapy clinical translation. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Keeping the Rhythm : Cardiac Pacemaker Cell Development

NARCIS (Netherlands)

Burkhard, S.B.

2017-01-01

The heart is the first organ to form and function in the developing vertebrate embryo. Its proper morphogenesis and function is crucial for survival. Here we focus on the development and characterization of a highly specialized subset of cardiac cells, the pacemaker cells. In the mammalian heart,

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

International Nuclear Information System (INIS)

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. 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

Cardiac Magnetic Resonance Feature Tracking Biventricular Two-Dimensional and Three-Dimensional Strains to Evaluate Ventricular Function in Children After Repaired Tetralogy of Fallot as Compared with Healthy Children.

Science.gov (United States)

Berganza, Fernando M; de Alba, Cesar Gonzalez; Özcelik, Nazire; Adebo, Dilachew

2017-03-01

Cardiac magnetic resonance imaging is an important tool to evaluate cardiac anatomy and ventricular size and function after repaired tetralogy of Fallot. Magnetic resonance tissue tagging is the gold standard for evaluation of myocardial strain. However, myocardial tagging strain requires tagged images to be obtained prospectively, during the scan and with limited temporal resolution. Cardiac magnetic resonance feature tracking is a new tool that allows the retrospective analysis of cine images. There is limited experience with cardiac magnetic resonance feature tracking strain analysis in children. The medical records of patients with repaired tetralogy of Fallot that had a cardiac magnetic resonance (CMR) study from December 2013 to June 2015 were reviewed. The control group included patients who underwent a CMR with normal cardiac anatomy and ventricular function. Global longitudinal, circumferential and radial strain parameters (2D and 3D) were obtained by retrospectively contouring cine images from ventricular short axis, two chamber and four chamber views using post-processing software (Circle CVi 42 , Calgary, Canada). The correlation between conventional ventricular function parameters and ventricular strain was performed using Pearson's correlation. The mean age of tetralogy of Fallot and control subjects was 12.4 and 14.1 years, respectively. In patients after repaired tetralogy of Fallot, the mean left ventricular global 2D and 3D circumferential strains were -17.4 ± 2.9 and -10.1 ± 3, respectively. The mean indexed right ventricular end-diastolic volume was 135.4 cc m 2  ± 46 compared to 75.7 cc m 2  ± 17 in control subjects (P = 0.0001, CI 95%). Left ventricular global circumferential 3D strain showed a statistically significant difference in patients after TOF repair compared to normal subjects (-10.1 ± 3 vs. -14.71 ± 1.9, P = 0.00001). A strong correlation between left ventricular global circumferential 3D strain and right

Aging impairs double-strand break repair by homologous recombination in Drosophila germ cells.

Science.gov (United States)

Delabaere, Laetitia; Ertl, Henry A; Massey, Dashiell J; Hofley, Carolyn M; Sohail, Faraz; Bienenstock, Elisa J; Sebastian, Hans; Chiolo, Irene; LaRocque, Jeannine R

2017-04-01

Aging is characterized by genome instability, which contributes to cancer formation and cell lethality leading to organismal decline. The high levels of DNA double-strand breaks (DSBs) observed in old cells and premature aging syndromes are likely a primary source of genome instability, but the underlying cause of their formation is still unclear. DSBs might result from higher levels of damage or repair defects emerging with advancing age, but repair pathways in old organisms are still poorly understood. Here, we show that premeiotic germline cells of young and old flies have distinct differences in their ability to repair DSBs by the error-free pathway homologous recombination (HR). Repair of DSBs induced by either ionizing radiation (IR) or the endonuclease I-SceI is markedly defective in older flies. This correlates with a remarkable reduction in HR repair measured with the DR-white DSB repair reporter assay. Strikingly, most of this repair defect is already present at 8 days of age. Finally, HR defects correlate with increased expression of early HR components and increased recruitment of Rad51 to damage in older organisms. Thus, we propose that the defect in the HR pathway for germ cells in older flies occurs following Rad51 recruitment. These data reveal that DSB repair defects arise early in the aging process and suggest that HR deficiencies are a leading cause of genome instability in germ cells of older animals. © 2016 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Repair models of cell survival and corresponding computer program for survival curve fitting

International Nuclear Information System (INIS)

Shen Xun; Hu Yiwei

1992-01-01

Some basic concepts and formulations of two repair models of survival, the incomplete repair (IR) model and the lethal-potentially lethal (LPL) model, are introduced. An IBM-PC computer program for survival curve fitting with these models was developed and applied to fit the survivals of human melanoma cells HX118 irradiated at different dose rates. Comparison was made between the repair models and two non-repair models, the multitar get-single hit model and the linear-quadratic model, in the fitting and analysis of the survival-dose curves. It was shown that either IR model or LPL model can fit a set of survival curves of different dose rates with same parameters and provide information on the repair capacity of cells. These two mathematical models could be very useful in quantitative study on the radiosensitivity and repair capacity of cells

Repair of radiation damage in mammalian cells: its relevance to environmental effects

International Nuclear Information System (INIS)

Han, A.; Elkind, M.M.

1979-01-01

Assessment of the potential biological hazards associated with energy production technologies involves the quantitation of risk on the basis of dose-effect dependencies, from which, it is hoped, some safety guidelines can be developed. Our current knowledge of the biological importance of damage/repair processes stems by and large from radiation studies which clearly demonstrate that cellular response to radiation depends upon the ability of cells to repair the damage. Apparently, the same is true for cellular response to different chemical agents. Drawing upon our experiences from radiation studies, we demonstrate the relevance of ongoing repair processes, as evident in the studies of radiation induced cell killing and neoplastic transformation, to the type of risk estimates that might be associated with the hazards from energy production technologies. The effect of repair on cell survival is considered. It is evident from our studies that in the region of small doses, repair of damage relative to cell lethality is of importance in estimating the magnitude of effect. Aside from the cytotoxic effects in terms of cell killing, one of the greatest concerns associated with energy production is the potential of a given technology, or its effluents, to produce cancer. It is therefore of importance to quantify the risk in this context of damage registration and possible effect of repair on damage expression. It has been generally established that exposure of normal cells in culture to a variety of known carcinogens results in neoplastic transformation. Our observations with C3H/10T1/2 cells in culture lend direct evidence for the hypothesis that reduced tumor incidences at low dose rates of radiation could be due to the repair of induced damage

Elimination of remaining undifferentiated induced pluripotent stem cells in the process of human cardiac cell sheet fabrication using a methionine-free culture condition.

Science.gov (United States)

Matsuura, Katsuhisa; Kodama, Fumiko; Sugiyama, Kasumi; Shimizu, Tatsuya; Hagiwara, Nobuhisa; Okano, Teruo

2015-03-01

Cardiac tissue engineering is a promising method for regenerative medicine. Although we have developed human cardiac cell sheets by integration of cell sheet-based tissue engineering and scalable bioreactor culture, the risk of contamination by induced pluripotent stem (iPS) cells in cardiac cell sheets remains unresolved. In the present study, we established a novel culture method to fabricate human cardiac cell sheets with a decreased risk of iPS cell contamination while maintaining viabilities of iPS cell-derived cells, including cardiomyocytes and fibroblasts, using a methionine-free culture condition. When cultured in the methionine-free condition, human iPS cells did not survive without feeder cells and could not proliferate or form colonies on feeder cells or in coculture with cells for cardiac cell sheet fabrication. When iPS cell-derived cells after the cardiac differentiation were transiently cultured in the methionine-free condition, gene expression of OCT3/4 and NANOG was downregulated significantly compared with that in the standard culture condition. Furthermore, in fabricated cardiac cell sheets, spontaneous and synchronous beating was observed in the whole area while maintaining or upregulating the expression of various cardiac and extracellular matrix genes. These findings suggest that human iPS cells are methionine dependent and a methionine-free culture condition for cardiac cell sheet fabrication might reduce the risk of iPS cell contamination.

High Density Sphere Culture of Adult Cardiac Cells Increases the Levels of Cardiac and Progenitor Markers and Shows Signs of Vasculogenesis

Directory of Open Access Journals (Sweden)

Kristina Vukusic

2013-01-01

Full Text Available 3D environment and high cell density play an important role in restoring and supporting the phenotypes of cells represented in cardiac tissues. The aim of this study was therefore to investigate the suitability of high density sphere (HDS cultures for studies of cardiomyocyte-, endothelial-, and stem-cell biology. Primary adult cardiac cells from nine human biopsies were cultured using different media for up to 9 weeks. The possibilities to favor a certain cell phenotype and induce production of extra cellular matrix (ECM were studied by histology, immunohistochemistry, and quantitative real-time PCR. Defined media gave significant increase in both cardiac- and progenitor-specific markers and also an intraluminal position of endothelial cells over time. Cardiac media showed indication of differentiation and maturity of HDS considering the ECM production and activities within NOTCH regulation but no additional cardiac differentiation. Endothelial media gave no positive effects on endothelial phenotype but increased proliferation without fibroblast overgrowth. In addition, indications for early vasculogenesis were found. It was also possible to affect the Wnt signaling in HDS by addition of a glycogen synthase kinase 3 (GSK3 inhibitor. In conclusion, these findings show the suitability of HDS as in vitro model for studies of cardiomyocyte-, endothelial-, and stem-cell biology.

Selective induction of DNA repair pathways in human B cells activated by CD4+ T cells.

Directory of Open Access Journals (Sweden)

Xiaosheng Wu

Full Text Available Greater than 75% of all hematologic malignancies derive from germinal center (GC or post-GC B cells, suggesting that the GC reaction predisposes B cells to tumorigenesis. Because GC B cells acquire expression of the highly mutagenic enzyme activation-induced cytidine deaminase (AID, GC B cells may require additional DNA repair capacity. The goal of this study was to investigate whether normal human B cells acquire enhanced expression of DNA repair factors upon AID induction. We first demonstrated that several DNA mismatch repair, homologous recombination, base excision repair, and ATR signaling genes were overexpressed in GC B cells relative to naïve and memory B cells, reflecting activation of a process we have termed somatic hyperrepair (SHR. Using an in vitro system, we next characterized activation signals required to induce AID expression and SHR. Although AID expression was induced by a variety of polyclonal activators, SHR induction strictly required signals provided by contact with activated CD4+ T cells, and B cells activated in this manner displayed reduced levels of DNA damage-induced apoptosis. We further show the induction of SHR is independent of AID expression, as GC B cells from AID-/-mice retained heightened expression of SHR proteins. In consideration of the critical role that CD4+ T cells play in inducing the SHR process, our data suggest a novel role for CD4+ T cells in the tumor suppression of GC/post-GC B cells.

Concise Review: Cardiac Disease Modeling Using Induced Pluripotent Stem Cells.

Science.gov (United States)

Yang, Chunbo; Al-Aama, Jumana; Stojkovic, Miodrag; Keavney, Bernard; Trafford, Andrew; Lako, Majlinda; Armstrong, Lyle

2015-09-01

Genetic cardiac diseases are major causes of morbidity and mortality. Although animal models have been created to provide some useful insights into the pathogenesis of genetic cardiac diseases, the significant species differences and the lack of genetic information for complex genetic diseases markedly attenuate the application values of such data. Generation of induced pluripotent stem cells (iPSCs) from patient-specific specimens and subsequent derivation of cardiomyocytes offer novel avenues to study the mechanisms underlying cardiac diseases, to identify new causative genes, and to provide insights into the disease aetiology. In recent years, the list of human iPSC-based models for genetic cardiac diseases has been expanding rapidly, although there are still remaining concerns on the level of functionality of iPSC-derived cardiomyocytes and their ability to be used for modeling complex cardiac diseases in adults. This review focuses on the development of cardiomyocyte induction from pluripotent stem cells, the recent progress in heart disease modeling using iPSC-derived cardiomyocytes, and the challenges associated with understanding complex genetic diseases. To address these issues, we examine the similarity between iPSC-derived cardiomyocytes and their ex vivo counterparts and how this relates to the method used to differentiate the pluripotent stem cells into a cardiomyocyte phenotype. We progress to examine categories of congenital cardiac abnormalities that are suitable for iPSC-based disease modeling. © AlphaMed Press.

Cardiac regeneration therapy: connections to cardiac physiology.

Science.gov (United States)

Takehara, Naofumi; Matsubara, Hiroaki

2011-12-01

Without heart transplantation, a large number of patients with failing hearts worldwide face poor outcomes. By means of cardiomyocyte regeneration, cardiac regeneration therapy is emerging with great promise as a means for restoring loss of cardiac function. However, the limited success of clinical trials using bone marrow-derived cells and myoblasts with heterogeneous constituents, transplanted at a wide range of cell doses, has led to disagreement on the efficacy of cell therapy. It is therefore essential to reevaluate the evidence for the efficacy of cell-based cardiac regeneration therapy, focusing on targets, materials, and methodologies. Meanwhile, the revolutionary innovation of cardiac regeneration therapy is sorely needed to help the millions of people who suffer heart failure from acquired loss of cardiomyocytes. Cardiac regeneration has been used only in limited species or as a developing process in the rodent heart; now, the possibility of cardiomyocyte turnover in the human heart is being revisited. In the pursuit of this concept, the use of cardiac stem/progenitor stem cells in the cardiac niche must be focused to usher in a second era of cardiac regeneration therapy for the severely injured heart. In addition, tissue engineering and cellular reprogramming will advance the next era of treatment that will enable current cell-based therapy to progress to "real" cardiac regeneration therapy. Although many barriers remain, the prevention of refractory heart failure through cardiac regeneration is now becoming a realistic possibility.

DNA repair in lens cells during chick embryo development

International Nuclear Information System (INIS)

Counis, M.F.; Chaudun, E.; Simonneau, L.; Courtois, Y.

1979-01-01

When chick lens epithelium is cultured in vitro, differentiation into lens fiber cells is accompanied by DNA degradation. This phenomenon of terminal differentiation was studied in the epithelium from embryos at the 6th and 11th days of development. DNA size and the ability of the cells to repair DNA damage induced by X-rays were analysed in alkaline sucrose gradients. In the 6-day epithelium a rapid degradation and complete lack of DNA repair were recorded. Similar observations have been made in previous studies on the 11-day sample, but here degradation is progressive and occurs after a lag of several days. In the younger epithelium, internal irradiation by [ 3 H)thymidine also had a drastic effect resembling that caused by X-rays. In order to assess the process of differentiation in the experimental system the synthesis of delta- and αcrystallins was monitored. Stage-related modifications in the rates of synthesis were recorded. The results confirm that the DNA repair system is impaired during terminal differentiation. The differences observed between the two stages may reflect either a developmental modification in DNA repair mechanisms or a change in the relative proportions of differentiating cells. An hypothesis is proposed in support of the latter case. (Auth.)

Measuring strand discontinuity-directed mismatch repair in yeast Saccharomyces cerevisiae by cell-free nuclear extracts.

Science.gov (United States)

Yuan, Fenghua; Lai, Fangfang; Gu, Liya; Zhou, Wen; El Hokayem, Jimmy; Zhang, Yanbin

2009-05-01

Mismatch repair corrects biosynthetic errors generated during DNA replication, whose deficiency causes a mutator phenotype and directly underlies hereditary non-polyposis colorectal cancer and sporadic cancers. Because of remarkably high conservation of the mismatch repair machinery between the budding yeast (Saccharomyces cerevisiae) and humans, the study of mismatch repair in yeast has provided tremendous insights into the mechanisms of this repair pathway in humans. In addition, yeast cells possess an unbeatable advantage over human cells in terms of the easy genetic manipulation, the availability of whole genome deletion strains, and the relatively low cost for setting up the system. Although many components of eukaryotic mismatch repair have been identified, it remains unclear if additional factors, such as DNA helicase(s) and redundant nuclease(s) besides EXO1, participate in eukaryotic mismatch repair. To facilitate the discovery of novel mismatch repair factors, we developed a straightforward in vitro cell-free repair system. Here, we describe the practical protocols for preparation of yeast cell-free nuclear extracts and DNA mismatch substrates, and the in vitro mismatch repair assay. The validity of the cell-free system was confirmed by the mismatch repair deficient yeast strain (Deltamsh2) and the complementation assay with purified yeast MSH2-MSH6.

Radioadaptive response. Efficient repair of radiation-induced DNA damage in adapted cells

International Nuclear Information System (INIS)

Ikushima, Takaji; Aritomi, Hisako; Morisita, Jun

1996-01-01

To verify the hypothesis that the induction of a novel, efficient repair mechanism for chromosomal DNA breaks may be involved in the radioadaptive response, the repair kinetics of DNA damage has been studied in cultured Chinese hamster V79 cells with single-cell gel electrophoresis. The cells were adapted by priming exposure with 5 cGy of γ-rays and 4-h incubation at 37C. There were no indication of any difference in the initial yields of DNA double-strand breaks induced by challenging doses from non-adapted cells and from adapted cells. The rejoining of DNA double-strand breaks was monitored over 120 min after the adapted cells were challenged with 5 or 1.5 Gy, doses at the same level to those used in the cytogenetical adaptive response. The rate of DNA damage repair in adapted cells was higher than that in non-adapted cells, and the residual damage was less in adapted cells than in non-adapted cells. These results indicate that the radioadaptive response may result from the induction of a novel, efficient DNA repair mechanism which leads to less residual damage, but not from the induction of protective functions that reduce the initial DNA damage

Association of myocardial cell necrosis with experimental cardiac hypertrophy

Energy Technology Data Exchange (ETDEWEB)

Revis, N W; Cameron, A J.V.

1979-01-01

Cardiac hypertrophy was induced in rabbits by injecting thyroxime or isoprenaline, or by surgically constricting the abdominal aorta. An increase in heart weight was associated with a change in the ratios of bound to free forms of five lysosomal enzymes, a change in serum creatine phosphokinase and lactate dehydrogenase, and a change in the morphology of the myocardial cells. Isoprenaline treatment for 5 days induced a maximal change in heart weight, in the ratio of lysosomal enzymes, and in the serum enzymes. Thyroxine treatment was required for 15 days before maximal changes in heart weight, ratio, and serum enzymes were observed. In contrast, coarctation of the aorta caused a progressive change in heart weight, in the ratio of lysosomal enzymes, and in serum enzymes. These results suggest that necrosis of the myocardial cells does indeed accompany cardiac hypertrophy. It was further observed that autophagosomes, degenerating mitochondria in the myocardial cells during the induction of cardiac hypertrophy, and myofibril lysis were found, all of which confirms the suggestion of myocardial cell necrosis in the experimentally enlarged heart.

A UV-sensitive human clonal cell line, RSa, which has low repair activity

International Nuclear Information System (INIS)

Suzuki, N.; Fuse, A.

1981-01-01

The repair activity of a human transformed cell line, RSa, which was found to be highly sensitive to the lethal effects of 254 mm far-ultraviolet radiation, was compared with that of HeLa cells by evaluating the range of UV-induced incorporation of [methyl- 3 H]thymidine ([ 3 H]dThd) or 5-[6- 3 H]bromodeoxyuridine ([ 3 H]BrdUrd) into deoxyribonucleic acid. Direct scintillation counting was used for measuring the extent of unscheduled DNA synthesis (UDS) in UV-irradiated cells, which were treated with hydroxyurea or with arginine deprivation. More quantitative measurements were made by using the density labeling and equilibrium centrifugation method for assaying repair replication. All the amounts of UDS and repair replication in RSa cells were markedly below those in HeLa cells. The possible relationships of the low repair activity to abnormally high UV sensitivity in RSa cells are discussed. (orig.)

Enhancement of postreplication repair in Chinese hamster cells

International Nuclear Information System (INIS)

D'Ambrosio, S.M.; Setlow, R.B.

1976-01-01

Alkaline sedimentation profiles of pulse-labeled DNA from Chinese hamster cells showed that DNA from cells treated with N-acetoxy-acetylaminofluorene or ultraviolet radiation was made in segments smaller than those from untreated cells. Cells treated with a small dose (2.5 μM) of N-acetoxy-acetylaminofluorene or(2.5 J . m -2 ) 254-nm radiation, several hours before a larger dose (7 to 10 μM) of N-acetoxy-acetylaminofluorene or 5.0 J . m -2 of 254-nm radiation, also synthesized small DNA after the second dose. However, the rate at which this small DNA was joined together into parental size was appreciably greater than in absence of the small dose. This enhancement of postreplication repair (as a result of the initial small dose) was not observed when cells were incubated with cycloheximide between the two treatments. The results suggest that N-acetoxy-acetylaminofluorene and ultraviolet-damaged DNA from Chinese hamster cells are repaired by similar postreplicative mechanisms that require de novo protein synthesis for enhancement

Simple suspension culture system of human iPS cells maintaining their pluripotency for cardiac cell sheet engineering.

Science.gov (United States)

Haraguchi, Yuji; Matsuura, Katsuhisa; Shimizu, Tatsuya; Yamato, Masayuki; Okano, Teruo

2015-12-01

In this study, a simple three-dimensional (3D) suspension culture method for the expansion and cardiac differentiation of human induced pluripotent stem cells (hiPSCs) is reported. The culture methods were easily adapted from two-dimensional (2D) to 3D culture without any additional manipulations. When hiPSCs were directly applied to 3D culture from 2D in a single-cell suspension, only a few aggregated cells were observed. However, after 3 days, culture of the small hiPSC aggregates in a spinner flask at the optimal agitation rate created aggregates which were capable of cell passages from the single-cell suspension. Cell numbers increased to approximately 10-fold after 12 days of culture. The undifferentiated state of expanded hiPSCs was confirmed by flow cytometry, immunocytochemistry and quantitative RT-PCR, and the hiPSCs differentiated into three germ layers. When the hiPSCs were subsequently cultured in a flask using cardiac differentiation medium, expression of cardiac cell-specific genes and beating cardiomyocytes were observed. Furthermore, the culture of hiPSCs on Matrigel-coated dishes with serum-free medium containing activin A, BMP4 and FGF-2 enabled it to generate robust spontaneous beating cardiomyocytes and these cells expressed several cardiac cell-related genes, including HCN4, MLC-2a and MLC-2v. This suggests that the expanded hiPSCs might maintain the potential to differentiate into several types of cardiomyocytes, including pacemakers. Moreover, when cardiac cell sheets were fabricated using differentiated cardiomyocytes, they beat spontaneously and synchronously, indicating electrically communicative tissue. This simple culture system might enable the generation of sufficient amounts of beating cardiomyocytes for use in cardiac regenerative medicine and tissue engineering. Copyright © 2013 John Wiley & Sons, Ltd.

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.

The Potential for Synovium-derived Stem Cells in Cartilage Repair

DEFF Research Database (Denmark)

Kubosch, Eva Johanna; Lang, Gernot Michael; Fürst, David

2018-01-01

for the treatment of large, isolated, full thickness cartilage defects. Several disadvantages such as the need for two surgical procedures or hypertrophic regenerative cartilage, underline the need for alternative cell sources. OBJECTIVE: Mesenchymal stem cells, particularly synovium-derived mesenchymal stem cells......, represent a promising cell source. Synovium-derived mesenchymal stem cells have attracted considerable attention since they display great chondrogenic potential and less hypertrophic differentiation than mesenchymal stem cells derived from bone marrow. The aim of this review was to summarize the current...... knowledge on the chondrogenic potential for synovial stem cells in regard to cartilage repair purposes. RESULTS: A literature search was carried out identifying 260 articles in the databases up to January 2017. Several in vitro and initial animal in vivo studies of cartilage repair using synovia stem cell...

Calvarial Suture-Derived Stem Cells and Their Contribution to Cranial Bone Repair

Directory of Open Access Journals (Sweden)

Daniel H. Doro

2017-11-01

Full Text Available In addition to the natural turnover during life, the bones in the skeleton possess the ability to self-repair in response to injury or disease-related bone loss. Based on studies of bone defect models, both processes are largely supported by resident stem cells. In the long bones, the source of skeletal stem cells has been widely investigated over the years, where the major stem cell population is thought to reside in the perivascular niche of the bone marrow. In contrast, we have very limited knowledge about the stem cells contributing to the repair of calvarial bones. In fact, until recently, the presence of specific stem cells in adult craniofacial bones was uncertain. These flat bones are mainly formed via intramembranous rather than endochondral ossification and thus contain minimal bone marrow space. It has been previously proposed that the overlying periosteum and underlying dura mater provide osteoprogenitors for calvarial bone repair. Nonetheless, recent studies have identified a major stem cell population within the suture mesenchyme with multiple differentiation abilities and intrinsic reparative potential. Here we provide an updated review of calvarial stem cells and potential mechanisms of regulation in the context of skull injury repair.

Enhanced capacity of DNA repair in human cytomegalovirus-infected cells

International Nuclear Information System (INIS)

Nishiyama, Y.; Rapp, F.

1981-01-01

Plaque formation in Vero cells by UV-irradiated herpes simplex virus was enhanced by infection with human cytomegalovirus (HCMV), UV irradiation, or treatment with methylmethanesulfonate. Preinfection of Vero cells with HCMV enhanced reactivation of UV-irradiated herpes simplex virus more significantly than did treatment with UV or methylmethanesulfonate alone. A similar enhancement by HCMV was observed in human embryonic fibroblasts, but not in xeroderma pigmentosum (XP12BE) cells. It was also found that HCMV infection enhanced hydroxyurea-resistant DNA synthesis induced by UV light or methylmethanesulfonate. Alkaline sucrose gradient sedimentation analysis revealed an enhanced rate of synthesis of all size classes of DNA in UV-irradiated HCMV-infected Vero cells. However, HCMV infection did not induce repairable lesions in cellular DNA and did not significantly inhibit host cell DNA synthesis, unlike UV or methylmethanesulfonate. These results indicate that HCMV enhanced DNA repair capacity in the host cells without producing detectable lesions in cellular DNA and without inhibiting DNA synthesis. This repair appeared to be error proof for UV-damaged herpes simplex virus DNA when tested with herpes simplex virus thymidine kinase-negative mutants

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

Electrical stimulation enhances cell migration and integrative repair in the meniscus

Science.gov (United States)

Yuan, Xiaoning; Arkonac, Derya E.; Chao, Pen-hsiu Grace; Vunjak-Novakovic, Gordana

2014-01-01

Electrical signals have been applied towards the repair of articular tissues in the laboratory and clinical settings for over seventy years. We focus on healing of the meniscus, a tissue essential to knee function with limited innate repair potential, which has been largely unexplored in the context of electrical stimulation. Here we demonstrate for the first time that electrical stimulation enhances meniscus cell migration and integrative tissue repair. We optimize pulsatile direct current electrical stimulation parameters on cells at the micro-scale, and apply these to healing of full-thickness defects in explants at the macro-scale. We report increased expression of the adenosine A2b receptor in meniscus cells after stimulation at the micro- and macro-scale, and propose a role for A2bR in meniscus electrotransduction. Taken together, these findings advance our understanding of the effects of electrical signals and their mechanisms of action, and contribute to developing electrotherapeutic strategies for meniscus repair. PMID:24419206

Stem Cell Technology in Cardiac Regeneration: A Pluripotent Stem Cell Promise.

Science.gov (United States)

Duelen, Robin; Sampaolesi, Maurilio

2017-02-01

Despite advances in cardiovascular biology and medical therapy, heart disorders are the leading cause of death worldwide. Cell-based regenerative therapies become a promising treatment for patients affected by heart failure, but also underline the need for reproducible results in preclinical and clinical studies for safety and efficacy. Enthusiasm has been tempered by poor engraftment, survival and differentiation of the injected adult stem cells. The crucial challenge is identification and selection of the most suitable stem cell type for cardiac regenerative medicine. Human pluripotent stem cells (PSCs) have emerged as attractive cell source to obtain cardiomyocytes (CMs), with potential applications, including drug discovery and toxicity screening, disease modelling and innovative cell therapies. Lessons from embryology offered important insights into the development of stem cell-derived CMs. However, the generation of a CM population, uniform in cardiac subtype, adult maturation and functional properties, is highly recommended. Moreover, hurdles regarding tumorigenesis, graft cell death, immune rejection and arrhythmogenesis need to be overcome in clinical practice. Here we highlight the recent progression in PSC technologies for the regeneration of injured heart. We review novel strategies that might overcome current obstacles in heart regenerative medicine, aiming at improving cell survival and functional integration after cell transplantation. Copyright © 2017. Published by Elsevier B.V.

Stem Cell Technology in Cardiac Regeneration: A Pluripotent Stem Cell Promise

Directory of Open Access Journals (Sweden)

Robin Duelen

2017-02-01

Full Text Available Despite advances in cardiovascular biology and medical therapy, heart disorders are the leading cause of death worldwide. Cell-based regenerative therapies become a promising treatment for patients affected by heart failure, but also underline the need for reproducible results in preclinical and clinical studies for safety and efficacy. Enthusiasm has been tempered by poor engraftment, survival and differentiation of the injected adult stem cells. The crucial challenge is identification and selection of the most suitable stem cell type for cardiac regenerative medicine. Human pluripotent stem cells (PSCs have emerged as attractive cell source to obtain cardiomyocytes (CMs, with potential applications, including drug discovery and toxicity screening, disease modelling and innovative cell therapies. Lessons from embryology offered important insights into the development of stem cell-derived CMs. However, the generation of a CM population, uniform in cardiac subtype, adult maturation and functional properties, is highly recommended. Moreover, hurdles regarding tumorigenesis, graft cell death, immune rejection and arrhythmogenesis need to be overcome in clinical practice. Here we highlight the recent progression in PSC technologies for the regeneration of injured heart. We review novel strategies that might overcome current obstacles in heart regenerative medicine, aiming at improving cell survival and functional integration after cell transplantation.

Simvastatin induces apoptosis by a Rho-dependent mechanism in cultured cardiac fibroblasts and myofibroblasts

International Nuclear Information System (INIS)

Copaja, Miguel; Venegas, Daniel; Aranguiz, Pablo; Canales, Jimena; Vivar, Raul; Catalan, Mabel; Olmedo, Ivonne; Rodriguez, Andrea E.; Chiong, Mario; Leyton, Lisette; Lavandero, Sergio; Diaz-Araya, Guillermo

2011-01-01

Several clinical trials have shown the beneficial effects of statins in the prevention of coronary heart disease. Additionally, statins promote apoptosis in vascular smooth muscle cells, in renal tubular epithelial cells and also in a variety of cell lines; yet, the effects of statins on cardiac fibroblast and myofibroblast, primarily responsible for cardiac tissue healing are almost unknown. Here, we investigated the effects of simvastatin on cardiac fibroblast and myofibroblast viability and studied the molecular cell death mechanism triggered by simvastatin in both cell types. Methods: Rat neonatal cardiac fibroblasts and myofibroblasts were treated with simvastatin (0.1-10 μM) up to 72 h. Cell viability and apoptosis were evaluated by trypan blue exclusion method and by flow cytometry, respectively. Caspase-3 activation and Rho protein levels and activity were also determined by Western blot and pull-down assay, respectively. Results: Simvastatin induces caspase-dependent apoptosis of cardiac fibroblasts and myofibroblasts in a concentration- and time-dependent manner, with greater effects on fibroblasts than myofibroblasts. These effects were prevented by mevalonate, farnesylpyrophosphate and geranylgeranylpyrophosphate, but not squalene. These last results suggest that apoptosis was dependent on small GTPases of the Rho family rather than Ras. Conclusion: Simvastatin triggered apoptosis of cardiac fibroblasts and myofibroblasts by a mechanism independent of cholesterol synthesis, but dependent of isoprenilation of Rho protein. Additionally, cardiac fibroblasts were more susceptible to simvastatin-induced apoptosis than cardiac myofibroblasts. Thus simvastatin could avoid adverse cardiac remodeling leading to a less fibrotic repair of the damaged tissues. - Research Highlights: → Simvastatin decreases CF and CMF viability independent of cholesterol synthesis. → Simvastatin induces CF and CMF apoptosis in a caspase-dependent manner being CMF more resistant

Concise Review: Fluorescent Reporters in Human Pluripotent Stem Cells: Contributions to Cardiac Differentiation and Their Applications in Cardiac Disease and Toxicity.

Science.gov (United States)

Den Hartogh, Sabine C; Passier, Robert

2016-01-01

In the last decade, since the first report of induced pluripotent stem cells, the stem cell field has made remarkable progress in the differentiation to specialized cell-types of various tissues and organs, including the heart. Cardiac lineage- and tissue-specific human pluripotent stem cell (hPSC) reporter lines have been valuable for the identification, selection, and expansion of cardiac progenitor cells and their derivatives, and for our current understanding of the underlying molecular mechanisms. In order to further advance the use of hPSCs in the fields of regenerative medicine, disease modeling, and preclinical drug development in cardiovascular research, it is crucial to identify functionally distinct cardiac subtypes and to study their biological signaling events and functional aspects in healthy and diseased conditions. In this review, we discuss the various strategies that have been followed to generate and study fluorescent reporter lines in hPSCs and provide insights how these reporter lines contribute to a better understanding and improvement of cell-based therapies and preclinical drug and toxicity screenings in the cardiac field. © AlphaMed Press.

Mouse embryonic stem cells, but not somatic cells, predominantly use homologous recombination to repair double-strand DNA breaks.

Science.gov (United States)

Tichy, Elisia D; Pillai, Resmi; Deng, Li; Liang, Li; Tischfield, Jay; Schwemberger, Sandy J; Babcock, George F; Stambrook, Peter J

2010-11-01

Embryonic stem (ES) cells give rise to all cell types of an organism. Since mutations at this embryonic stage would affect all cells and be detrimental to the overall health of an organism, robust mechanisms must exist to ensure that genomic integrity is maintained. To test this proposition, we compared the capacity of murine ES cells to repair DNA double-strand breaks with that of differentiated cells. Of the 2 major pathways that repair double-strand breaks, error-prone nonhomologous end joining (NHEJ) predominated in mouse embryonic fibroblasts, whereas the high fidelity homologous recombinational repair (HRR) predominated in ES cells. Microhomology-mediated end joining, an emerging repair pathway, persisted at low levels in all cell types examined. The levels of proteins involved in HRR and microhomology-mediated end joining were highly elevated in ES cells compared with mouse embryonic fibroblasts, whereas those for NHEJ were quite variable, with DNA Ligase IV expression low in ES cells. The half-life of DNA Ligase IV protein was also low in ES cells. Attempts to increase the abundance of DNA Ligase IV protein by overexpression or inhibition of its degradation, and thereby elevate NHEJ in ES cells, were unsuccessful. When ES cells were induced to differentiate, however, the level of DNA Ligase IV protein increased, as did the capacity to repair by NHEJ. The data suggest that preferential use of HRR rather than NHEJ may lend ES cells an additional layer of genomic protection and that the limited levels of DNA Ligase IV may account for the low level of NHEJ activity.

Integration of genomics, proteomics, and imaging for cardiac stem cell therapy

International Nuclear Information System (INIS)

Chun, Hyung J.; Wilson, Kitch O.; Huang, Mei; Wu, Joseph C.

2007-01-01

Cardiac stem cell therapy is beginning to mature as a valid treatment for heart disease. As more clinical trials utilizing stem cells emerge, it is imperative to establish the mechanisms by which stem cells confer benefit in cardiac diseases. In this paper, we review three methods - molecular cellular imaging, gene expression profiling, and proteomic analysis - that can be integrated to provide further insights into the role of this emerging therapy. (orig.)

Repair of UV-induced DNA damage and its inhibition by etoposide in Sf9 insect cells: comparison with human cells

International Nuclear Information System (INIS)

Chandna, Sudhir; Dwarakanath, B.S.; Moorthy, Ganesh; Jain, Charu

2004-01-01

In the present investigation, the kinetics of DNA repair in a lepidopteran cell line Sf9 (derived from the ovaries of Spodoptera frugiperda) following UV-irradiation was compared with the responses in a human embryonic kidney cell. DNA repair was studied by analyzing the kinetics of induction and removal of repair related strand breaks using the alkaline single cell gel electrophoresis and Halo assays. Since topoisomerases play important roles in the cellular responses to UV-induced damage, the effects of etoposideon DNA repair kinetics was also studied

Characterization of a mutant rat kangaroo cell line with alterations in the cell cycle and DNA repair

OpenAIRE

Miyaji, E.N.; Johnson, R.T.; Downes, C.S.; Eveno, E.; Mezzina, M.; Sarasin, A.; Menck, C.F.M.

2000-01-01

Using a positive selection system for isolating DNA replication and repair related mutants, we isolated a clone from a rat kangaroo cell line (PtK2) that has increased sensitivity to UV light. Characterization of this clone indicated normal post-replication repair after UV irradiation, and normal removal rates of cyclobutane pyrimidine dimers and pyrimidine(6-4)pyrimidone photoproducts by excision repair. However, this cell line has decreased ability to make early incisions on damaged DNA, po...

Correlation of Fragmented QRS with Right Ventricular Indexes and Fibrosis in Patients with Repaired Tetralogy of Fallot, by Cardiac Magnetic Resonance Imaging

Directory of Open Access Journals (Sweden)

Zahra Alizadeh Sani

2017-09-01

Full Text Available Background: Repair of tetralogy of fallot (TOF is associated with diffuse myocardial fibrosis. Cardiac magnetic resonance imaging (CMR can visualize the areas with myocardial fibrosis. Presence of fragmented QRS (fQRS implies the presence of the underlying myocardial scar. Despite the strong association between fQRS and myocardial pathologies, the impact of fQRS with myocardial fibrosis in post-TOF correction is unknown. Objectives: Here, we evaluated the possible predictive role of fQRS in repaired TOF cases and its relationship with cardiac function. Patients and Methods: Thirty two patients with previous history of repaired TOF were enrolled. The extent of fQRS was evaluated according to the number of leads with fQRS. After electrocardiographic evaluation, the participants underwent CMR. Results: Results showed a significant relationship between the right ventricular (RV systolic diameter and fQRS (P = 0.014. Also, an inverse linear relationship was found between the number of fQRS edges and RVEF (r = 0.77, P = 0.0001. The mean QRS duration in those with positive and negative fQRS was 132 mm and 115.8 mm (P = 0.0001. Furthermore, a linear correlation was observed between the number of edges and the percentage of scar tissue (r = 0.88, P = 0.001. However, no relevance between gender and fQRS was detected (P = 0.26, and the relationship between RV diastolic diameter and fQRS was not significant (P = 0.1. Thus, fQRS could be used as a marker of RV systolic dysfunction in patients with tetralogy of fallot. Conclusions: We suggested the fQRS as a surrogate indicator of RV dysfunction in repaired TOF patients and showed that diagnostic and prognostic information of the patients were available by fQRS.

Genome-Nuclear Lamina Interactions Regulate Cardiac Stem Cell Lineage Restriction.

Science.gov (United States)

Poleshko, Andrey; Shah, Parisha P; Gupta, Mudit; Babu, Apoorva; Morley, Michael P; Manderfield, Lauren J; Ifkovits, Jamie L; Calderon, Damelys; Aghajanian, Haig; Sierra-Pagán, Javier E; Sun, Zheng; Wang, Qiaohong; Li, Li; Dubois, Nicole C; Morrisey, Edward E; Lazar, Mitchell A; Smith, Cheryl L; Epstein, Jonathan A; Jain, Rajan

2017-10-19

Progenitor cells differentiate into specialized cell types through coordinated expression of lineage-specific genes and modification of complex chromatin configurations. We demonstrate that a histone deacetylase (Hdac3) organizes heterochromatin at the nuclear lamina during cardiac progenitor lineage restriction. Specification of cardiomyocytes is associated with reorganization of peripheral heterochromatin, and independent of deacetylase activity, Hdac3 tethers peripheral heterochromatin containing lineage-relevant genes to the nuclear lamina. Deletion of Hdac3 in cardiac progenitor cells releases genomic regions from the nuclear periphery, leading to precocious cardiac gene expression and differentiation into cardiomyocytes; in contrast, restricting Hdac3 to the nuclear periphery rescues myogenesis in progenitors otherwise lacking Hdac3. Our results suggest that availability of genomic regions for activation by lineage-specific factors is regulated in part through dynamic chromatin-nuclear lamina interactions and that competence of a progenitor cell to respond to differentiation signals may depend upon coordinated movement of responding gene loci away from the nuclear periphery. Copyright © 2017 Elsevier Inc. All rights reserved.

CALCIUM-DRIVEN TRANSCRIPTION OF CARDIAC SPECIFYING GENE PROGRAM IN LIVER STEM CELLS

Science.gov (United States)

We have previously shown that a cloned liver stem cell line (WB F344) acquires a cardiac phenotype when seeded in a cardiac microenvironment in vivo and ex vivo. Here we investigated the mechanisms of this transdifferentiation in early (cell, rat neonatal ventricu...

Dendritic cell-associated immune inflammation of cardiac mucosa: a possible factor in the formation of Barrett's esophagus.

Science.gov (United States)

Bobryshev, Yuri V; Tran, Dinh; Killingsworth, Murray C; Buckland, Michael; Lord, Reginald V N

2009-03-01

The development of Barrett's esophagus is poorly understood, but it has been suggested that cardiac mucosa is a precursor of intestinal type metaplasia and that inflammation of cardiac mucosa may play a role in the formation of Barrett's esophagus. The present study was undertaken to examine the presence and distribution of immune-inflammatory cells in cardiac mucosa, specifically focusing on dendritic cells because of their importance as regulators of immune reactions. Endoscopic biopsy specimens were obtained from 12 patients with cardiac mucosa without Barrett's esophagus or adenocarcinoma and from 21 patients with Barrett's esophagus without dysplasia (intestinal metaplasia). According to histology, in nine of the 21 specimens with Barrett's esophagus, areas of mucosa composed of cardiac type epithelium-lined glands were present as well. Immunohistochemical staining and electron microscopy were used to examine immune-inflammatory cells in paraffin-embedded sections. Immune-inflammatory cells, including T cells, B cells, dendritic cells, macrophages, and mast cells, were present in the connective tissue matrix that surrounded cardiac type epithelium-lined glands in all patients with cardiac mucosa. Clustering of dendritic cells with each other and with lymphocytes and the intrusion of dendritic cells between glandular mucus cells were observed. In the Barrett's esophagus specimens that contained cardiac type glands, computerized CD83 expression quantitation revealed that there were more dendritic cells in cardiac mucosa than in intestinal metaplasia. Immune-inflammatory infiltrates containing dendritic cells are consistently present in cardiac mucosa. The finding of a larger number of dendritic cells in areas of cardiac mucosa in Barrett's esophagus biopsies suggests that the immune inflammation of cardiac mucosa might play a role in modifying the local tissue environment to promote the development of specialized intestinal type metaplasia.

Biologically improved nanofibrous scaffolds for cardiac tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Bhaarathy, V. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Nanoscience and Technology, School of Physical Sciences, Bharathiar University, Coimbatore 641046 (India); Lee Kong Chian School of Medicine, Nanyang Technological University, 138673 (Singapore); Venugopal, J., E-mail: nnijrv@nus.edu.sg [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Gandhimathi, C. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Ponpandian, N.; Mangalaraj, D. [Department of Nanoscience and Technology, School of Physical Sciences, Bharathiar University, Coimbatore 641046 (India); Ramakrishna, S. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore)

2014-11-01

Nanofibrous structure developed by electrospinning technology provides attractive extracellular matrix conditions for the anchorage, migration and differentiation of stem cells, including those responsible for regenerative medicine. Recently, biocomposite nanofibers consisting of two or more polymeric blends are electrospun more tidily in order to obtain scaffolds with desired functional and mechanical properties depending on their applications. The study focuses on one such an attempt of using copolymer Poly(L-lactic acid)-co-poly (ε-caprolactone) (PLACL), silk fibroin (SF) and Aloe Vera (AV) for fabricating biocomposite nanofibrous scaffolds for cardiac tissue engineering. SEM micrographs of fabricated electrospun PLACL, PLACL/SF and PLACL/SF/AV nanofibrous scaffolds are porous, beadless, uniform nanofibers with interconnected pores and obtained fibre diameter in the range of 459 ± 22 nm, 202 ± 12 nm and 188 ± 16 nm respectively. PLACL, PLACL/SF and PLACL/SF/AV electrospun mats obtained at room temperature with an elastic modulus of 14.1 ± 0.7, 9.96 ± 2.5 and 7.0 ± 0.9 MPa respectively. PLACL/SF/AV nanofibers have more desirable properties to act as flexible cell supporting scaffolds compared to PLACL for the repair of myocardial infarction (MI). The PLACL/SF and PLACL/SF/AV nanofibers had a contact angle of 51 ± 12° compared to that of 133 ± 15° of PLACL alone. Cardiac cell proliferation was increased by 21% in PLACL/SF/AV nanofibers compared to PLACL by day 6 and further increased to 42% by day 9. Confocal analysis for cardiac expression proteins myosin and connexin 43 was observed better by day 9 compared to all other nanofibrous scaffolds. The results proved that the fabricated PLACL/SF/AV nanofibrous scaffolds have good potentiality for the regeneration of infarcted myocardium in cardiac tissue engineering. - Highlights: • Fabricated nanofibrous scaffolds are porous, beadless and uniform structures. • PLACL/SF/AV nanofibers improve the

Biologically improved nanofibrous scaffolds for cardiac tissue engineering

International Nuclear Information System (INIS)

Bhaarathy, V.; Venugopal, J.; Gandhimathi, C.; Ponpandian, N.; Mangalaraj, D.; Ramakrishna, S.

2014-01-01

Nanofibrous structure developed by electrospinning technology provides attractive extracellular matrix conditions for the anchorage, migration and differentiation of stem cells, including those responsible for regenerative medicine. Recently, biocomposite nanofibers consisting of two or more polymeric blends are electrospun more tidily in order to obtain scaffolds with desired functional and mechanical properties depending on their applications. The study focuses on one such an attempt of using copolymer Poly(L-lactic acid)-co-poly (ε-caprolactone) (PLACL), silk fibroin (SF) and Aloe Vera (AV) for fabricating biocomposite nanofibrous scaffolds for cardiac tissue engineering. SEM micrographs of fabricated electrospun PLACL, PLACL/SF and PLACL/SF/AV nanofibrous scaffolds are porous, beadless, uniform nanofibers with interconnected pores and obtained fibre diameter in the range of 459 ± 22 nm, 202 ± 12 nm and 188 ± 16 nm respectively. PLACL, PLACL/SF and PLACL/SF/AV electrospun mats obtained at room temperature with an elastic modulus of 14.1 ± 0.7, 9.96 ± 2.5 and 7.0 ± 0.9 MPa respectively. PLACL/SF/AV nanofibers have more desirable properties to act as flexible cell supporting scaffolds compared to PLACL for the repair of myocardial infarction (MI). The PLACL/SF and PLACL/SF/AV nanofibers had a contact angle of 51 ± 12° compared to that of 133 ± 15° of PLACL alone. Cardiac cell proliferation was increased by 21% in PLACL/SF/AV nanofibers compared to PLACL by day 6 and further increased to 42% by day 9. Confocal analysis for cardiac expression proteins myosin and connexin 43 was observed better by day 9 compared to all other nanofibrous scaffolds. The results proved that the fabricated PLACL/SF/AV nanofibrous scaffolds have good potentiality for the regeneration of infarcted myocardium in cardiac tissue engineering. - Highlights: • Fabricated nanofibrous scaffolds are porous, beadless and uniform structures. • PLACL/SF/AV nanofibers improve the

Wnt/β-Catenin Stimulation and Laminins Support Cardiovascular Cell Progenitor Expansion from Human Fetal Cardiac Mesenchymal Stromal Cells

Directory of Open Access Journals (Sweden)

Agneta Månsson-Broberg

2016-04-01

Full Text Available The intrinsic regenerative capacity of human fetal cardiac mesenchymal stromal cells (MSCs has not been fully characterized. Here we demonstrate that we can expand cells with characteristics of cardiovascular progenitor cells from the MSC population of human fetal hearts. Cells cultured on cardiac muscle laminin (LN-based substrata in combination with stimulation of the canonical Wnt/β-catenin pathway showed increased gene expression of ISL1, OCT4, KDR, and NKX2.5. The majority of cells stained positive for PDGFR-α, ISL1, and NKX2.5, and subpopulations also expressed the progenitor markers TBX18, KDR, c-KIT, and SSEA-1. Upon culture of the cardiac MSCs in differentiation media and on relevant LNs, portions of the cells differentiated into spontaneously beating cardiomyocytes, and endothelial and smooth muscle-like cells. Our protocol for large-scale culture of human fetal cardiac MSCs enables future exploration of the regenerative functions of these cells in the context of myocardial injury in vitro and in vivo.

Histamine-2 receptor antagonist famotidine modulates cardiac stem cell characteristics in hypertensive heart disease

Directory of Open Access Journals (Sweden)

Sherin Saheera

2017-10-01

Full Text Available Background Cardiac stem cells (CSCs play a vital role in cardiac homeostasis. A decrease in the efficiency of cardiac stem cells is speculated in various cardiac abnormalities. The maintenance of a healthy stem cell population is essential for the prevention of adverse cardiac remodeling leading to cardiac failure. Famotidine, a histamine-2 receptor antagonist, is currently used to treat ulcers of the stomach and intestines. In repurposing the use of the drug, reduction of cardiac hypertrophy and improvement in cardiac function of spontaneously hypertensive rats (SHR was reported by our group. Given that stem cells are affected in cardiac pathologies, the effect of histamine-2 receptor antagonism on CSC characteristics was investigated. Methods To examine whether famotidine has a positive effect on CSCs, spontaneously hypertensive rats (SHR treated with the drug were sacrificed; and CSCs isolated from atrial appendages was evaluated. Six-month-old male SHRs were treated with famotidine (30 mg/kg/day for two months. The effect of famotidine treatment on migration, proliferation and survival of CSCs was compared with untreated SHRs and normotensive Wistar rats. Results Functional efficiency of CSCs from SHR was compromised relative to that in Wistar rat. Famotidine increased the migration and proliferation potential, along with retention of stemness of CSCs in treated SHRs. Cellular senescence and oxidative stress were also reduced. The expression of H2R was unaffected by the treatment. Discussion As anticipated, CSCs from SHRs were functionally impaired. Stem cell attributes of famotidine-treated SHRs was comparable to that of Wistar rats. Therefore, in addition to being cardioprotective, the histamine 2 receptor antagonist modulated cardiac stem cells characteristics. Restoration of stem cell efficiency by famotidine is possibly mediated by reduction of oxidative stress as the expression of H2R was unaffected by the treatment. Maintenance of

Human induced pluripotent cells resemble embryonic stem cells demonstrating enhanced levels of DNA repair and efficacy of nonhomologous end-joining

Energy Technology Data Exchange (ETDEWEB)

Fan Jinshui; Robert, Carine [Department of Radiation Oncology, University of Maryland School of Medicine, 655 West Baltimore Street, BRB 7-023A, Baltimore, MD 21201 (United States); Jang, Yoon-Young; Liu Hua; Sharkis, Saul; Baylin, Stephen Bruce [Johns Hopkins University School of Medicine, Department of Oncology, Baltimore, MD 21231-1000 (United States); Rassool, Feyruz Virgilia, E-mail: frassool@som.umaryland.edu [Department of Radiation Oncology, University of Maryland School of Medicine, 655 West Baltimore Street, BRB 7-023A, Baltimore, MD 21201 (United States)

2011-08-01

Highlights: {yields} iPSC and hESC demonstrate a similar cell cycle profile, with increased S phase cells and decreased G0/G1. {yields} iPSC and hESC increased ROS and decreased DSBs, compared with differentiated parental cells. {yields} iPSC and hESC demonstrate elevated DSB repair activity, including nonhomologous end-joining, compared with differentiated parental cells. {yields} iPSC however show a partial apoptotic response to DNA damage, compared to hESC. {yields} DNA damage responses may constitute important markers for the efficacy of iPSC reprogramming. - Abstract: To maintain the integrity of the organism, embryonic stem cells (ESC) need to maintain their genomic integrity in response to DNA damage. DNA double strand breaks (DSBs) are one of the most lethal forms of DNA damage and can have disastrous consequences if not repaired correctly, leading to cell death, genomic instability and cancer. How human ESC (hESC) maintain genomic integrity in response to agents that cause DSBs is relatively unclear. Adult somatic cells can be induced to 'dedifferentiate' into induced pluripotent stem cells (iPSC) and reprogram into cells of all three germ layers. Whether iPSC have reprogrammed the DNA damage response is a critical question in regenerative medicine. Here, we show that hESC demonstrate high levels of endogenous reactive oxygen species (ROS) which can contribute to DNA damage and may arise from high levels of metabolic activity. To potentially counter genomic instability caused by DNA damage, we find that hESC employ two strategies: First, these cells have enhanced levels of DNA repair proteins, including those involved in repair of DSBs, and they demonstrate elevated nonhomologous end-joining (NHEJ) activity and repair efficacy, one of the main pathways for repairing DSBs. Second, they are hypersensitive to DNA damaging agents, as evidenced by a high level of apoptosis upon irradiation. Importantly, iPSC, unlike the parent cells they are derived

Human induced pluripotent cells resemble embryonic stem cells demonstrating enhanced levels of DNA repair and efficacy of nonhomologous end-joining

International Nuclear Information System (INIS)

Fan Jinshui; Robert, Carine; Jang, Yoon-Young; Liu Hua; Sharkis, Saul; Baylin, Stephen Bruce; Rassool, Feyruz Virgilia

2011-01-01

Highlights: → iPSC and hESC demonstrate a similar cell cycle profile, with increased S phase cells and decreased G0/G1. → iPSC and hESC increased ROS and decreased DSBs, compared with differentiated parental cells. → iPSC and hESC demonstrate elevated DSB repair activity, including nonhomologous end-joining, compared with differentiated parental cells. → iPSC however show a partial apoptotic response to DNA damage, compared to hESC. → DNA damage responses may constitute important markers for the efficacy of iPSC reprogramming. - Abstract: To maintain the integrity of the organism, embryonic stem cells (ESC) need to maintain their genomic integrity in response to DNA damage. DNA double strand breaks (DSBs) are one of the most lethal forms of DNA damage and can have disastrous consequences if not repaired correctly, leading to cell death, genomic instability and cancer. How human ESC (hESC) maintain genomic integrity in response to agents that cause DSBs is relatively unclear. Adult somatic cells can be induced to 'dedifferentiate' into induced pluripotent stem cells (iPSC) and reprogram into cells of all three germ layers. Whether iPSC have reprogrammed the DNA damage response is a critical question in regenerative medicine. Here, we show that hESC demonstrate high levels of endogenous reactive oxygen species (ROS) which can contribute to DNA damage and may arise from high levels of metabolic activity. To potentially counter genomic instability caused by DNA damage, we find that hESC employ two strategies: First, these cells have enhanced levels of DNA repair proteins, including those involved in repair of DSBs, and they demonstrate elevated nonhomologous end-joining (NHEJ) activity and repair efficacy, one of the main pathways for repairing DSBs. Second, they are hypersensitive to DNA damaging agents, as evidenced by a high level of apoptosis upon irradiation. Importantly, iPSC, unlike the parent cells they are derived from, mimic hESC in their ROS levels

Skin appendage-derived stem cells: cell biology and potential for wound repair

OpenAIRE

Xie, Jiangfan; Yao, Bin; Han, Yutong; Huang, Sha; Fu, Xiaobing

2016-01-01

Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. These stem cells also participate in the repair of the epidermis after injuries, inducing restoration of tissue integrity and function of damaged tissue. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. In this review, we summarize the current knowledge of skin appendage-derived stem cells, including their fundament...

A randomized controlled trial of cell salvage in routine cardiac surgery.

Science.gov (United States)

Klein, Andrew A; Nashef, Samer A M; Sharples, Linda; Bottrill, Fiona; Dyer, Matthew; Armstrong, Johanna; Vuylsteke, Alain

2008-11-01

Previous trials have indicated that cell salvage may reduce allogeneic blood transfusion during cardiac surgery, but these studies have limitations, including inconsistent use of other blood transfusion-sparing strategies. We designed a randomized controlled trial to determine whether routine cell salvage for elective uncomplicated cardiac surgery reduces blood transfusion and is cost effective in the setting of a rigorous transfusion protocol and routine administration of antifibrinolytics. Two-hundred-thirteen patients presenting for first-time coronary artery bypass grafting and/or cardiac valve surgery were prospectively randomized to control or cell salvage groups. The latter group had blood aspirate during surgery and mediastinal drainage the first 6 h after surgery processed in a cell saver device and autotransfused. All patients received tranexamic acid and were subjected to an algorithm for red blood cell and hemostatic blood factor transfusion. There was no difference between the two groups in the proportion of patients exposed to allogeneic blood (32% in both groups, relative risk 1.0 P = 0.89). At current blood products and cell saver prices, the use of cell salvage increased the costs per patient by a minimum of $103. When patients who had mediastinal re-exploration for bleeding were excluded (as planned in the protocol), significantly fewer units of allogeneic red blood cells were transfused in the cell salvage compared with the control group (65 vs 100 U, relative risk 0.71 P = 0.04). In patients undergoing routine first-time cardiac surgery in an institution with a rigorous blood conservation program, the routine use of cell salvage does not further reduce the proportion of patients exposed to allogeneic blood transfusion. However, patients who do not have excessive bleeding after surgery receive significantly fewer units of blood with cell salvage. Although the use of cell savage may reduce the demand for blood products during cardiac surgery, this

Modern Perspectives on Numerical Modeling of Cardiac Pacemaker Cell

Science.gov (United States)

Maltsev, Victor A.; Yaniv, Yael; Maltsev, Anna V.; Stern, Michael D.; Lakatta, Edward G.

2015-01-01

Cardiac pacemaking is a complex phenomenon that is still not completely understood. Together with experimental studies, numerical modeling has been traditionally used to acquire mechanistic insights in this research area. This review summarizes the present state of numerical modeling of the cardiac pacemaker, including approaches to resolve present paradoxes and controversies. Specifically we discuss the requirement for realistic modeling to consider symmetrical importance of both intracellular and cell membrane processes (within a recent “coupled-clock” theory). Promising future developments of the complex pacemaker system models include the introduction of local calcium control, mitochondria function, and biochemical regulation of protein phosphorylation and cAMP production. Modern numerical and theoretical methods such as multi-parameter sensitivity analyses within extended populations of models and bifurcation analyses are also important for the definition of the most realistic parameters that describe a robust, yet simultaneously flexible operation of the coupled-clock pacemaker cell system. The systems approach to exploring cardiac pacemaker function will guide development of new therapies, such as biological pacemakers for treating insufficient cardiac pacemaker function that becomes especially prevalent with advancing age. PMID:24748434

Uterine-derived progenitor cells are immunoprivileged and effectively improve cardiac regeneration when used for cell therapy.

Science.gov (United States)

Ludke, Ana; Wu, Jun; Nazari, Mansoreh; Hatta, Kota; Shao, Zhengbo; Li, Shu-Hong; Song, Huifang; Ni, Nathan C; Weisel, Richard D; Li, Ren-Ke

2015-07-01

Cell therapy to prevent cardiac dysfunction after myocardial infarction (MI) is less effective in aged patients because aged cells have decreased regenerative capacity. Allogeneic transplanted stem cells (SCs) from young donors are usually rejected. Maintaining transplanted SC immunoprivilege may dramatically improve regenerative outcomes. The uterus has distinct immune characteristics, and we showed that reparative uterine SCs home to the myocardium post-MI. Here, we identify immunoprivileged uterine SCs and assess their effects on cardiac regeneration after allogeneic transplantation. We found more than 20% of cells in the mouse uterus have undetectable MHC I expression by flow cytometry. Uterine MHC I((neg)) and MHC I((pos)) cells were separated by magnetic cell sorting. The MHC I((neg)) population expressed the SC markers CD34, Sca-1 and CD90, but did not express MHC II or c-kit. In vitro, MHC I((neg)) and ((pos)) SCs show colony formation and endothelial differentiation capacity. In mixed leukocyte co-culture, MHC I((neg)) cells showed reduced cell death and leukocyte proliferation compared to MHC I((pos)) cells. MHC I((neg)) and ((pos)) cells had significantly greater angiogenic capacity than mesenchymal stem cells. The benefits of intramyocardial injection of allogeneic MHC I((neg)) cells after MI were comparable to syngeneic bone marrow cell transplantation, with engraftment in cardiac tissue and limited recruitment of CD4 and CD8 cells up to 21 days post-MI. MHC I((neg)) cells preserved cardiac function, decreased infarct size and improved regeneration post-MI. This new source of immunoprivileged cells can induce neovascularization and could be used as allogeneic cell therapy for regenerative medicine. Copyright © 2015 Elsevier Ltd. All rights reserved.

DNA repair in a Fanconi's anemia fibroblast cell strain

International Nuclear Information System (INIS)

Fornace, A.J. Jr.; Little, J.B.; Weichselbaum, R.R.

1979-01-01

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.)

DNA repair in a Fanconi's anemia fibroblast cell strain

Energy Technology Data Exchange (ETDEWEB)

Fornace, Jr, A J; Little, J B [Harvard School of Public Health, Boston, MA (USA); Weichselbaum, R R [Harvard Medical School, Boston, MA (USA)

1979-01-26

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.

Quantitative aspects of repair of potentially lethal damage in mammalian cells

International Nuclear Information System (INIS)

Iliakis, G.; Pohlit, W.

1979-01-01

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)

Inhibition of DNA replication and repair by anthralin or danthron in cultured human cells

International Nuclear Information System (INIS)

Clark, J.M.; Hanawalt, P.C.

1982-01-01

The comparative effects of the tumor promoter anthralin and its analog, danthron, on semiconservative DNA replication and DNA repair synthesis were studied in cultured human cells. Bromodeoxyuridine was used as density label together with 3 H-thymidine to distinguish replication from repair synthesis in isopycnic CsCl gradients. Anthralin at 1.1 microgram inhibited replication in T98G cells by 50%. In cells treated with 0.4 or 1.3 microM anthralin and additive effect was observed on the inhibition of replication by ultraviolet light (254 nm). In cells irradiated with 20 J/m2, 2.3 microM anthralin was required to inhibit repair synthesis by 50%. Thus there was no selective inhibitory effect of anthralin on repair synthesis. Danthron exhibited no detectable effect on either semiconservative replication or repair synthesis at concentrations below about 5.0 microM. Neither compound stimulated repair synthesis in the absence of ultraviolet irradiation. Thus, anthralin and danthron do not appear to react with DNA to form adducts that are subject to excision repair. Although both compounds appear to intercalate into supercoiled DNA in vitro to a limited extent, the degree of unwinding introduced by the respective drugs does not correlate with their relative effects on DNA synthesis in vivo. Therefore the inhibitory effect of anthralin on DNA replication and repair synthesis in T98G cells does not appear to result from the direct interaction of the drug with DNA

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

International Nuclear Information System (INIS)

Glazunov, A.V.

1988-01-01

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

Induced pluripotent stem cell-derived cardiac progenitors differentiate to cardiomyocytes and form biosynthetic tissues.

Directory of Open Access Journals (Sweden)

Nicolas Christoforou

Full Text Available The mammalian heart has little capacity to regenerate, and following injury the myocardium is replaced by non-contractile scar tissue. Consequently, increased wall stress and workload on the remaining myocardium leads to chamber dilation, dysfunction, and heart failure. Cell-based therapy with an autologous, epigenetically reprogrammed, and cardiac-committed progenitor cell source could potentially reverse this process by replacing the damaged myocardium with functional tissue. However, it is unclear whether cardiac progenitor cell-derived cardiomyocytes are capable of attaining levels of structural and functional maturity comparable to that of terminally-fated cardiomyocytes. Here, we first describe the derivation of mouse induced pluripotent stem (iPS cells, which once differentiated allow for the enrichment of Nkx2-5(+ cardiac progenitors, and the cardiomyocyte-specific expression of the red fluorescent protein. We show that the cardiac progenitors are multipotent and capable of differentiating into endothelial cells, smooth muscle cells and cardiomyocytes. Moreover, cardiac progenitor selection corresponds to cKit(+ cell enrichment, while cardiomyocyte cell-lineage commitment is concomitant with dual expression of either cKit/Flk1 or cKit/Sca-1. We proceed to show that the cardiac progenitor-derived cardiomyocytes are capable of forming electrically and mechanically coupled large-scale 2D cell cultures with mature electrophysiological properties. Finally, we examine the cell progenitors' ability to form electromechanically coherent macroscopic tissues, using a physiologically relevant 3D culture model and demonstrate that following long-term culture the cardiomyocytes align, and form robust electromechanical connections throughout the volume of the biosynthetic tissue construct. We conclude that the iPS cell-derived cardiac progenitors are a robust cell source for tissue engineering applications and a 3D culture platform for pharmacological

Safe genetic modification of cardiac stem cells using a site-specific integration technique.

Science.gov (United States)

Lan, Feng; Liu, Junwei; Narsinh, Kazim H; Hu, Shijun; Han, Leng; Lee, Andrew S; Karow, Marisa; Nguyen, Patricia K; Nag, Divya; Calos, Michele P; Robbins, Robert C; Wu, Joseph C

2012-09-11

Human cardiac progenitor cells (hCPCs) are a promising cell source for regenerative repair after myocardial infarction. Exploitation of their full therapeutic potential may require stable genetic modification of the cells ex vivo. Safe genetic engineering of stem cells, using facile methods for site-specific integration of transgenes into known genomic contexts, would significantly enhance the overall safety and efficacy of cellular therapy in a variety of clinical contexts. We used the phiC31 site-specific recombinase to achieve targeted integration of a triple fusion reporter gene into a known chromosomal context in hCPCs and human endothelial cells. Stable expression of the reporter gene from its unique chromosomal integration site resulted in no discernible genomic instability or adverse changes in cell phenotype. Namely, phiC31-modified hCPCs were unchanged in their differentiation propensity, cellular proliferative rate, and global gene expression profile when compared with unaltered control hCPCs. Expression of the triple fusion reporter gene enabled multimodal assessment of cell fate in vitro and in vivo using fluorescence microscopy, bioluminescence imaging, and positron emission tomography. Intramyocardial transplantation of genetically modified hCPCs resulted in significant improvement in myocardial function 2 weeks after cell delivery, as assessed by echocardiography (P=0.002) and MRI (P=0.001). We also demonstrated the feasibility and therapeutic efficacy of genetically modifying differentiated human endothelial cells, which enhanced hind limb perfusion (Pmodification system is a safe, efficient tool to enable site-specific integration of reporter transgenes in progenitor and differentiated cell types.

RAD51 Is a Selective DNA Repair Target to Radiosensitize Glioma Stem Cells.

Science.gov (United States)

King, Harry O; Brend, Tim; Payne, Helen L; Wright, Alexander; Ward, Thomas A; Patel, Karan; Egnuni, Teklu; Stead, Lucy F; Patel, Anjana; Wurdak, Heiko; Short, Susan C

2017-01-10

Patients with glioblastoma die from local relapse despite surgery and high-dose radiotherapy. Resistance to radiotherapy is thought to be due to efficient DNA double-strand break (DSB) repair in stem-like cells able to survive DNA damage and repopulate the tumor. We used clinical samples and patient-derived glioblastoma stem cells (GSCs) to confirm that the DSB repair protein RAD51 is highly expressed in GSCs, which are reliant on RAD51-dependent DSB repair after radiation. RAD51 expression and RAD51 foci numbers fall when these cells move toward astrocytic differentiation. In GSCs, the small-molecule RAD51 inhibitors RI-1 and B02 prevent RAD51 focus formation, reduce DNA DSB repair, and cause significant radiosensitization. We further demonstrate that treatment with these agents combined with radiation promotes loss of stem cells defined by SOX2 expression. This indicates that RAD51-dependent repair represents an effective and specific target in GSCs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

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

International Nuclear Information System (INIS)

Bedford, P.; Fichtinger-Schepman, A.M.; Shellard, S.A.; Walker, M.C.; Masters, J.R.; Hill, B.T.

1988-01-01

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

Repair of soft X-ray damage to mammalian cell DNA

Energy Technology Data Exchange (ETDEWEB)

Meldrum, R.A.; Wharton, C.W. (Birmingham Univ. (UK). Dept. of Biochemistry)

1990-10-01

Inhibitors of polymerase {alpha} (hydroxyurea and cytosine arabinoside) and an inhibitor of polymerase {beta} and ''delta (di-deoxythymidine) had equal inhibitory effects on repair synthesis in the first 15 min after irradiation of Chinese hamster ovary cells with soft x-rays produced from a laser plasma. Polymerase {alpha} inhibitors had considerably more effect after 15 min following irradiation. This implies that polymerase {alpha}, {beta}, and/or {delta} are all equally active in the initial stages of repair synthesis after soft X-radiation, but {alpha}-activity is more prominent in later stages of repair synthesis. Polymerase {alpha} is thought to catalyse long-patch repair synthesis, while polymerase {beta} is thought to catalyse short-patch repair. Polymerase {delta} has been shown to be active in DNA repair synthesis, but its precise function is as yet uncertain. (author).

Twist1 Controls a Cell-Specification Switch Governing Cell Fate Decisions within the Cardiac Neural Crest

Science.gov (United States)

Vincentz, Joshua W.; Firulli, Beth A.; Lin, Andrea; Spicer, Douglas B.; Howard, Marthe J.; Firulli, Anthony B.

2013-01-01

Neural crest cells are multipotent progenitor cells that can generate both ectodermal cell types, such as neurons, and mesodermal cell types, such as smooth muscle. The mechanisms controlling this cell fate choice are not known. The basic Helix-loop-Helix (bHLH) transcription factor Twist1 is expressed throughout the migratory and post-migratory cardiac neural crest. Twist1 ablation or mutation of the Twist-box causes differentiation of ectopic neuronal cells, which molecularly resemble sympathetic ganglia, in the cardiac outflow tract. Twist1 interacts with the pro-neural factor Sox10 via its Twist-box domain and binds to the Phox2b promoter to repress transcriptional activity. Mesodermal cardiac neural crest trans-differentiation into ectodermal sympathetic ganglia-like neurons is dependent upon Phox2b function. Ectopic Twist1 expression in neural crest precursors disrupts sympathetic neurogenesis. These data demonstrate that Twist1 functions in post-migratory neural crest cells to repress pro-neural factors and thereby regulate cell fate determination between ectodermal and mesodermal lineages. PMID:23555309

DNA repair

International Nuclear Information System (INIS)

Van Zeeland, A.A.

1984-01-01

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

The role of undifferentiated adipose-derived stem cells in peripheral nerve repair.

Science.gov (United States)

Zhang, Rui; Rosen, Joseph M

2018-05-01

Peripheral nerve injuries impose significant health and economic consequences, yet no surgical repair can deliver a complete recovery of sensory or motor function. Traditional methods of repair are less than ideal: direct coaptation can only be performed when tension-free repair is possible, and transplantation of nerve autograft can cause donor-site morbidity and neuroma formation. Cell-based therapy delivered via nerve conduits has thus been explored as an alternative method of nerve repair in recent years. Stem cells are promising sources of the regenerative core material in a nerve conduit because stem cells are multipotent in function, abundant in supply, and more accessible than the myelinating Schwann cells. Among different types of stem cells, undifferentiated adipose-derived stem cell (uASC), which can be processed from adipose tissue in less than two hours, is a promising yet underexplored cell type. Studies of uASC have emerged in the past decade and have shown that autologous uASCs are non-immunogenic, easy to access, abundant in supply, and efficacious at promoting nerve regeneration. Two theories have been proposed as the primary regenerative mechanisms of uASC: in situ trans-differentiation towards Schwann cells, and secretion of trophic and anti-inflammatory factors. Future studies need to fully elucidate the mechanisms, side effects, and efficacy of uASC-based nerve regeneration so that uASCs can be utilized in clinical settings.

Identification and functional characterization of cardiac pacemaker cells in zebrafish.

Directory of Open Access Journals (Sweden)

Federico Tessadori

Full Text Available In the mammalian heart a conduction system of nodes and conducting cells generates and transduces the electrical signals evoking myocardial contractions. Specialized pacemaker cells initiating and controlling cardiac contraction rhythmicity are localized in an anatomically identifiable structure of myocardial origin, the sinus node. We previously showed that in mammalian embryos sinus node cells originate from cardiac progenitors expressing the transcription factors T-box transcription factor 3 (Tbx3 and Islet-1 (Isl1. Although cardiac development and function are strikingly conserved amongst animal classes, in lower vertebrates neither structural nor molecular distinguishable components of a conduction system have been identified, questioning its evolutionary origin. Here we show that zebrafish embryos lacking the LIM/homeodomain-containing transcription factor Isl1 display heart rate defects related to pacemaker dysfunction. Moreover, 3D reconstructions of gene expression patterns in the embryonic and adult zebrafish heart led us to uncover a previously unidentified, Isl1-positive and Tbx2b-positive region in the myocardium at the junction of the sinus venosus and atrium. Through their long interconnecting cellular protrusions the identified Isl1-positive cells form a ring-shaped structure. In vivo labeling of the Isl1-positive cells by transgenic technology allowed their isolation and electrophysiological characterization, revealing their unique pacemaker activity. In conclusion we demonstrate that Isl1-expressing cells, organized as a ring-shaped structure around the venous pole, hold the pacemaker function in the adult zebrafish heart. We have thereby identified an evolutionary conserved, structural and molecular distinguishable component of the cardiac conduction system in a lower vertebrate.

Meta-analysis of cell-based CaRdiac stUdiEs (ACCRUE) in patients with acute myocardial infarction based on individual patient data

DEFF Research Database (Denmark)

Gyöngyösi, Mariann; Wojakowski, Wojciech; Lemarchand, Patricia

2015-01-01

RATIONALE: The meta-Analysis of Cell-based CaRdiac study is the first prospectively declared collaborative multinational database, including individual data of patients with ischemic heart disease treated with cell therapy. OBJECTIVE: We analyzed the safety and efficacy of intracoronary cell...... therapy after acute myocardial infarction (AMI), including individual patient data from 12 randomized trials (ASTAMI, Aalst, BOOST, BONAMI, CADUCEUS, FINCELL, REGENT, REPAIR-AMI, SCAMI, SWISS-AMI, TIME, LATE-TIME; n=1252). METHODS AND RESULTS: The primary end point was freedom from combined major adverse.......1), end-diastolic volume, or systolic volume were observed compared with controls. These results were not influenced by anterior AMI location, reduced baseline ejection fraction, or the use of MRI for assessing left ventricular parameters. CONCLUSIONS: This meta-analysis of individual patient data from...

Immediate and repair induced DNA double strand breaks in mammalian cells

International Nuclear Information System (INIS)

Bryant, P.E.

1986-01-01

It seems logical to postulate that double strand breaks (dsb) arising both at the time of irradiation and via repair processes are potentially equally damaging for a cell in terms of the potential to induce chromosomal aberrations. However, in some cell systems the repair of double es or es-ssb sites may run concurrently with the incision so that these lesions do not remain open for long: hence the lack of accumulation of dsb during repair. The rate of incision will thus determine both the accumulation and the probability of exchanges leading to chromosomal aberrations between these and other frank dsb. Rapid incision leading to a large additional pool of dsb appears to be the case in Chinese hamster V79 cells. Some evidence also exists for the conversion of base damage, via dsb, into deletion type chromatid aberrations which accumulate in irradiated G2 human cells treated with ara C. A small fraction of dsb, probably arising both at the time of irradiation as well as enzymatically during repair of base or sugar damage, appears to be either left unrepaired, yielding deletion type chromosomal aberrations, or is misrepaired, yielding exchange aberrations. The induction of these aberrations appears to be of central importance in the biological effects of ionizing radiation such as mutations, oncogenic transformation, and cell death. 52 refs., 5 figs

Annexins are instrumental for efficient plasma membrane repair in cancer cells.

Science.gov (United States)

Lauritzen, Stine Prehn; Boye, Theresa Louise; Nylandsted, Jesper

2015-09-01

Plasma membrane stress can cause damage to the plasma membrane, both when imposed by the extracellular environment and by enhanced oxidative stress. Cells cope with these injuries by rapidly activating their plasma membrane repair system, which is triggered by Ca(2+) influx at the wound site. The repair system is highly dynamic, depends on both lipid and protein components, and include cytoskeletal reorganization, membrane replacements, and membrane fusion events. Cancer cells experience enhanced membrane stress when navigating through dense extracellular matrix, which increases the frequency of membrane injuries. In addition, increased motility and oxidative stress further increase the risk of plasma membrane lesions. Cancer cells compensate by overexpressing Annexin proteins including Annexin A2 (ANXA2). Annexin family members can facilitate membrane fusion events and wound healing by binding to negatively charged phospholipids in the plasma membrane. Plasma membrane repair in cancer cells depends on ANXA2 protein, which is recruited to the wound site and forms a complex with the Ca(2+)-binding EF-hand protein S100A11. Here they regulate actin accumulation around the wound perimeter, which is required for wound closure. In this review, we will discuss the requirement for Annexins, S100 proteins and actin cytoskeleton in the plasma membrane repair response of cancer cells, which reveals a novel avenue for targeting metastatic cancers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Concise Review: Pluripotent Stem Cell-Derived Cardiac Cells, A Promising Cell Source for Therapy of Heart Failure: Where Do We Stand?

Science.gov (United States)

Gouadon, Elodie; Moore-Morris, Thomas; Smit, Nicoline W; Chatenoud, Lucienne; Coronel, Ruben; Harding, Sian E; Jourdon, Philippe; Lambert, Virginie; Rucker-Martin, Catherine; Pucéat, Michel

2016-01-01

Heart failure is still a major cause of hospitalization and mortality in developed countries. Many clinical trials have tested the use of multipotent stem cells as a cardiac regenerative medicine. The benefit for the patients of this therapeutic intervention has remained limited. Herein, we review the pluripotent stem cells as a cell source for cardiac regeneration. We more specifically address the various challenges of this cell therapy approach. We question the cell delivery systems, the immune tolerance of allogenic cells, the potential proarrhythmic effects, various drug mediated interventions to facilitate cell grafting and, finally, we describe the pathological conditions that may benefit from such an innovative approach. As members of a transatlantic consortium of excellence of basic science researchers and clinicians, we propose some guidelines to be applied to cell types and modes of delivery in order to translate pluripotent stem cell cardiac derivatives into safe and effective clinical trials. © 2015 AlphaMed Press.

Mesenchymal Stem Cells in Tissue Growth and Repair

OpenAIRE

Kalinina, N.I.; Sysoeva, V.Yu.; Rubina, K.A.; Parfenova, Ye.V.; Tkachuk, V.A.

2011-01-01

It has been established in the recent several decades that stem cells play a crucial role in tissue renewal and regeneration. Mesenchymal stem cells (MSCs) are part of the most important population of adult stem cells. These cells have hereby been identified for the very first time and subsequently isolated from bone marrow stroma. Bone marrow-derived MSCs have been believed to play the role of a source of cells for the renewal and repair of connective tissues, including bone, cartilage and a...

Molecular dosimetry of chemical mutagens: measurement of molecular dose and DNA repair germ cells

International Nuclear Information System (INIS)

Sega, G.A.

1975-01-01

Molecular dosimetry in the germ cells of male mice is reviewed with regard to in vivo alkylation of sperm heads, in vivo alkylation of sperm DNA, and possible alkylation of sperm protamine. DNA repair in male germ cells is reviewed with regard to basic design of experiments, DNA repair in various stages of spermatogenesis, effect of protamine on DNA repair following treatment with EMS or x radiation, and induction of DNA repair by methyl methanesulfonate, propyl methanesulfonate, and isopropyl methanesulfonate

Visualization of DNA double-strand break repair: From molecules to cells

NARCIS (Netherlands)

Krawczyk, Przemek M.; Stap, Jan; Aten, Jacob A.

2008-01-01

DNA double-strand break (DSB) signaling and repair processes are positioned at the crossroad of nuclear pathways that regulate DNA replication, cell division, senescence and apoptosis. Importantly, errors in DSB repair may lead to lethal or potentially tumorigenic chromosome rearrangements.

Cardiac Metastasis in Renal Cell Carcinoma

African Journals Online (AJOL)

abp

2015-10-21

Oct 21, 2015 ... Metastatic disease of the heart is over twenty times more common than primary heart tumors [1]. They are among the least known and highly debated issues in oncology, and few systematic studies are devoted to this topic. Cardiac involvement in renal cell carcinoma (RCC) commonly arises from direct ...

Cell Seeding Densities in Autologous Chondrocyte Implantation Techniques for Cartilage Repair.

Science.gov (United States)

Foldager, Casper Bindzus; Gomoll, Andreas H; Lind, Martin; Spector, Myron

2012-04-01

Cartilage repair techniques have been among the most intensively investigated treatments in orthopedics for the past decade, and several different treatment modalities are currently available. Despite the extensive research effort within this field, the generation of hyaline cartilage remains a considerable challenge. There are many parameters attendant to each of the cartilage repair techniques that can affect the amount and types of reparative tissue generated in the cartilage defect, and some of the most fundamental of these parameters have yet to be fully investigated. For procedures in which in vitro-cultured autologous chondrocytes are implanted under a periosteal or synthetic membrane cover, or seeded onto a porous membrane or scaffold, little is known about how the number of cells affects the clinical outcome. Few published clinical studies address the cell seeding density that was employed. The principal objective of this review is to provide an overview of the cell seeding densities used in cell-based treatments currently available in the clinic for cartilage repair. Select preclinical studies that have informed the use of specific cell seeding densities in the clinic are also discussed.

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

International Nuclear Information System (INIS)

Wang, Z.; Wu, X.; Friedberg, E.C.

1993-01-01

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 Mg 2+ 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

Repair of DNA double-strand breaks and cell killing by charged particles

Science.gov (United States)

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

It has been suggested that it is not simple double-strand breaks (dsb) but the non-reparable breaks which correlate well with the high biological effectiveness of high LET radiations for cell killing. We have compared the effects of charged particles on cell death in 3 pairs of cell lines which are normal or defective in the repair of DNA dsbs. For the cell lines SL3-147, M10, and SX10 which are deficient in DNA dsb repair, RBE values were close to unity for cell killing induced by charged particles with linear energy transfer (LET) up to 200 keV/mum and were even smaller than unity for the LET region greater than 300 keV/mum. The inactivation cross section (ICS) increased with LET for all 3 pairs. The ICS of dsb repair deficient mutants was always larger than that of their parents for all the LET ranges, but with increasing LET the difference in ICS between the mutant and its parent became smaller. Since a small difference in ICS remained at LET of about 300 keV/mum, dsb repair may still take place at this high LET, even if its role is apparently small. These results suggest that the DNA repair system does not play a major role in protection against the attack of high LET radiations and that a main cause of cell death is non-reparable dsb which are produced at a higher yield compared with low LET radiations. No correlation was observed between DNA content or nuclear area and ICS.

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

International Nuclear Information System (INIS)

Gedik, C.M.; Collins, A.R.; Ewen, S.W.B.

1992-01-01

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 10 9 daltons are detected. (Author)

Evidence for multiple repair pathways of double-strand DNA breaks in Chinese hamster cells

International Nuclear Information System (INIS)

Giaccia, A.J.; Weistein, R.; Stamato, T.D.; Roosa, R.

1984-01-01

XR-1 is a mutant of the Chinese hamster cell (CHO-K1) which is abnormally sensitive to killing by gamma rays in G/sub 1/ (D37 = 27 rads vs. 318 for parent) and early S phases of the cell cycle but has near normal resistance in late S and early G/sub 2/ (Somatic Cell Genetics, 9:165-173, 1983). Complementation studies between XR-1 and its parent indicate that this sensitivity to gamma rays is a recessive phenotype. Both the XR-1 and its parent cell are able to repair single strand DNA breaks. However, in comparison to its parental cell, the XR-1 cell is markedly deficient in the repair of double strand DNA breaks introduced by gamma irradiation during the sensitive G/sub 1/-early S period, while in the late S-G/sub 2/ resistant period the repair is similar in both cells. This correlation suggests that an unrepaired double strand DNA break is the lethal lesion and that at least two pathways for the repair of these lesions exist in mammalian cells

Textile-templated electrospun anisotropic scaffolds for regenerative cardiac tissue engineering.

Science.gov (United States)

Şenel Ayaz, H Gözde; Perets, Anat; Ayaz, Hasan; Gilroy, Kyle D; Govindaraj, Muthu; Brookstein, David; Lelkes, Peter I

2014-10-01

For patients with end-stage heart disease, the access to heart transplantation is limited due to the shortage of donor organs and to the potential for rejection of the donated organ. Therefore, current studies focus on bioengineering approaches for creating biomimetic cardiac patches that will assist in restoring cardiac function, by repairing and/or regenerating the intrinsically anisotropic myocardium. In this paper we present a simplified, straightforward approach for creating bioactive anisotropic cardiac patches, based on a combination of bioengineering and textile-manufacturing techniques in concert with nano-biotechnology based tissue-engineering stratagems. Using knitted conventional textiles, made of cotton or polyester yarns as template targets, we successfully electrospun anisotropic three-dimensional scaffolds from poly(lactic-co-glycolic) acid (PLGA), and thermoplastic polycarbonate-urethane (PCU, Bionate(®)). The surface topography and mechanical properties of textile-templated anisotropic scaffolds significantly differed from those of scaffolds electrospun from the same materials onto conventional 2-D flat-target electrospun scaffolds. Anisotropic textile-templated scaffolds electrospun from both PLGA and PCU, supported the adhesion and proliferation of H9C2 cardiac myoblasts cell line, and guided the cardiac tissue-like anisotropic organization of these cells in vitro. All cell-seeded PCU scaffolds exhibited mechanical properties comparable to those of a human heart, but only the cells on the polyester-templated scaffolds exhibited prolonged spontaneous synchronous contractility on the entire engineered construct for 10 days in vitro at a near physiologic frequency of ∼120 bpm. Taken together, the methods described here take advantage of straightforward established textile manufacturing strategies as an efficient and cost-effective approach to engineering 3D anisotropic, elastomeric PCU scaffolds that can serve as a cardiac patch. Copyright �

Direct contact with endoderm-like cells efficiently induces cardiac progenitors from mouse and human pluripotent stem cells.

Directory of Open Access Journals (Sweden)

Hideki Uosaki

Full Text Available RATIONALE: Pluripotent stem cell-derived cardiac progenitor cells (CPCs have emerged as a powerful tool to study cardiogenesis in vitro and a potential cell source for cardiac regenerative medicine. However, available methods to induce CPCs are not efficient or require high-cost cytokines with extensive optimization due to cell line variations. OBJECTIVE: Based on our in-vivo observation that early endodermal cells maintain contact with nascent pre-cardiac mesoderm, we hypothesized that direct physical contact with endoderm promotes induction of CPCs from pluripotent cells. METHOD AND RESULT: To test the hypothesis, we cocultured mouse embryonic stem (ES cells with the endodermal cell line End2 by co-aggregation or End2-conditioned medium. Co-aggregation resulted in strong induction of Flk1(+ PDGFRa(+ CPCs in a dose-dependent manner, but the conditioned medium did not, indicating that direct contact is necessary for this process. To determine if direct contact with End2 cells also promotes the induction of committed cardiac progenitors, we utilized several mouse ES and induced pluripotent (iPS cell lines expressing fluorescent proteins under regulation of the CPC lineage markers Nkx2.5 or Isl1. In agreement with earlier data, co-aggregation with End2 cells potently induces both Nkx2.5(+ and Isl1(+ CPCs, leading to a sheet of beating cardiomyocytes. Furthermore, co-aggregation with End2 cells greatly promotes the induction of KDR(+ PDGFRa(+ CPCs from human ES cells. CONCLUSIONS: Our co-aggregation method provides an efficient, simple and cost-effective way to induce CPCs from mouse and human pluripotent cells.

The inhibition of repair in UV irradiated human cells

International Nuclear Information System (INIS)

Collins, A.R.S.; Schor, S.L.; Johnson, R.T.

1977-01-01

Three different assay procedures are used to determine the effects of hydroxyurea on excision repair in UV-irradiated HeLa cells. At the cytological level, incubation of UV-irradiated metaphase cells with hydroxyurea caused chromosome decondensation. Using a modified alkaline sucrose gradient sedimentation technique involving minimal lysis before centrifugation, a marked retardation was found in the sedimentation of DNA from UV-irradiated cells incubated for a short period with hydroxyurea. The effect of hydroxyurea on the incorporation of [ 3 H]thymidine by UV-irradiated G1 cells was found to depend on the concentration of thymidine present in the medium. The results point to an inhibition of repair DNA synthesis by hydroxyurea (or deoxyadenosine), at the level of the supply of DNA precursors, i.e. in the same way that these agents inhibit semiconservative DNA synthesis. In the presence of these inhibitors, single-strand gaps accumulate in the DNA

Intrinsic radiosensitivity and PLD repair in osteosarcoma cell lines

International Nuclear Information System (INIS)

Sugimoto, M.; Toguchida, J.; Kotoura, Y.; Yamamuro, T.; Utsumi, H.

1992-01-01

The response to radiation of seven osteosarcoma cell lines was analysed by in vitro colony-forming assay and compared with that of eight human fibroblast strains. The values of D 0 , the surviving fraction after 2 Gy (S2Gy), and the mean inactivation dose (D-bar) of osteosarcoma cells in log-phase culture were significantly higher than those of fibroblast strains (p<0.01). PLD (potentially lethal damage) repair of osteosarcoma cells evaluated in the plateau phase of growth showed great variation for enhancement of survival, although all of the values were maximised within 12 h after irradiation. In the osteosarcoma, intrinsic radiosensitivity in vitro reflected the clinical response to radiation. However, the capacity for PLD repair might not be a good indicator for predicting the results of radiation therapy. (author)

DNA repair and induction of plasminogen activator in human fetal cells treated with ultraviolet light

International Nuclear Information System (INIS)

Ben-Ishai, R.; Sharon, R.; Rothman, M.; Miskin, R.

1984-01-01

We have tested human fetal fibroblasts for development associated changes in DNA repair by utilizing nucleoid sedimentation as an assay for excision repair. Among skin fibroblasts the rate of excision repair was significantly higher in non-fetal cells than in fibroblasts derived from an 8 week fetus; this was evident by a delay in both the relaxation and the restoration of DNA supercoiling in nucleoids after irradiation. Skin fibroblasts derived at 12 week gestation were more repair proficient than those derived at 8 week gestation. However, they exhibited a somewhat lower rate of repair than non-fetal cells. The same fetal and non-fetal cells were also tested for induction of the protease plasminogen activator (PA) after u.v. irradiation. Enhancement of PA was higher in skin fibroblasts derived at 8 week than in those derived at 12 week gestation and was absent in non-fetal skin fibroblasts. These results are consistent with our previous findings that in human cells u.v. light-induced PA synthesis is correlated with reduced DNA repair capacity. Excision repair and PA inducibility were found to depend on tissue of origin in addition to gestational stage, as shown for skin and lung fibroblasts from the same 12 week fetus. Lung compared to skin fibroblasts exhibited lower repair rates and produced higher levels of PA after irradiation. The sedimentation velocity of nucleoids, prepared from unirradiated fibroblasts, in neutral sucrose gradients with or without ethidium bromide, indicated the presence of DNA strand breaks in fetal cells. It is proposed that reduced DNA repair in fetal cells may result from alterations in DNA supercoiling, and that persistent DNA strand breaks enhance transcription of PA gene(s)

[Stem cells: searching predisposition to cardiac commitment by surface markers expression].

Science.gov (United States)

Lara-Martínez, Luis A; Gutiérrez-Villegas, Ingrid; Arenas-Luna, Victor M; Hernández-Gutierrez, Salomón

2018-01-05

It is well-known that cardiovascular diseases are the leading cause of death worldwide, and represent an important economic burden to health systems. In an attempt to solve this problem, stem cell therapy has emerged as a therapeutic option. Within the last 20 years, a great variety of stem cells have been used in different myocardial infarction models. Up until now, the use of cardiac stem cells (CSCs) has seemed to be the best option, but the inaccessibility and scarcity of these cells make their use unreliable. Additionally, there is a high risk as they have to be obtained directly from the heart of the patient. Unlike CSCs, adult stem cells originating from bone marrow or adipose tissue, among others, appear to be an attractive option due to their easier accessibility and abundance, but particularly due to the probable existence of cardiac progenitors among their different sub-populations. In this review an analysis is made of the surface markers present in CSCs compared with other adult stem cells. This suggested the pre-existence of cells sharing specific surface markers with CSCs, a predictable immunophenotype present in some cells, although in low proportions, and with a potential of cardiac differentiation that could be similar to CSCs, thus increasing their therapeutic value. This study highlights new perspectives regarding MSCs that would enable some of these sub-populations to be differentiated at cardiac tissue level. Copyright © 2017 Instituto Nacional de Cardiología Ignacio Chávez. Publicado por Masson Doyma México S.A. All rights reserved.

Fibre autoradiography of repair and replication in DNA from single cells: the effect of DNA synthesis inhibitors

Energy Technology Data Exchange (ETDEWEB)

Ockey, C.H.

1982-04-01

DNA fibre autoradiography, after incorporation of high specific activity /sup 3/H-thymidine and /sup 3/H-deoxycytidine, has been used to investigate repair in DNA fibres from single cells following UV, or methyl-methane sulphonate (MMS) treatment. Asynchronously growing human fibroblasts, leucocytes, and HeLa cells at different phases of the cell cycle have been investigated. Isotope incorporation in repair could be differentiated from that involved in replication by the distribution and density of silver grains along the DNA fibres. Grain distribution due to repair was continuous over long stretches of the fibres and was at a low density, occasionally interspersed with short slightly denser segments. Replication labelling on the other hand, was dense and usually in short tandem segments. Repair labelling was of a similar overall density in fibres from a single cell, but differed in intensity from cell to cell. In mutagen treated Go (leucocytes) of G/sub 1/ (HeLa cells), repair labelling was not increased by the presence of the DNA inhibitors, hydroxyurea (HU) or 5-fluorodeoxyuridine (FUdR). Repair was not detectable in S cells however without the use of these inhibitors to reduce endogenous nucleoside production. FUdR enhanced the repair labelling in S cells only slightly, while HU increased it beyond that observed in UV irradiated, HU treated, G/sub 1/ cells. The intensity of repair labelling in fibres from mutagen treated S cells appears to be proportional to the degree of reduction of DNA chain elongation in replicons.

Rigid microenvironments promote cardiac differentiation of mouse and human embryonic stem cells

Science.gov (United States)

Arshi, Armin; Nakashima, Yasuhiro; Nakano, Haruko; Eaimkhong, Sarayoot; Evseenko, Denis; Reed, Jason; Stieg, Adam Z.; Gimzewski, James K.; Nakano, Atsushi

2013-04-01

While adult heart muscle is the least regenerative of tissues, embryonic cardiomyocytes are proliferative, with embryonic stem (ES) cells providing an endless reservoir. In addition to secreted factors and cell-cell interactions, the extracellular microenvironment has been shown to play an important role in stem cell lineage specification, and understanding how scaffold elasticity influences cardiac differentiation is crucial to cardiac tissue engineering. Though previous studies have analyzed the role of matrix elasticity on the function of differentiated cardiomyocytes, whether it affects the induction of cardiomyocytes from pluripotent stem cells is poorly understood. Here, we examine the role of matrix rigidity on cardiac differentiation using mouse and human ES cells. Culture on polydimethylsiloxane (PDMS) substrates of varied monomer-to-crosslinker ratios revealed that rigid extracellular matrices promote a higher yield of de novo cardiomyocytes from undifferentiated ES cells. Using a genetically modified ES system that allows us to purify differentiated cardiomyocytes by drug selection, we demonstrate that rigid environments induce higher cardiac troponin T expression, beating rate of foci, and expression ratio of adult α- to fetal β- myosin heavy chain in a purified cardiac population. M-mode and mechanical interferometry image analyses demonstrate that these ES-derived cardiomyocytes display functional maturity and synchronization of beating when co-cultured with neonatal cardiomyocytes harvested from a developing embryo. Together, these data identify matrix stiffness as an independent factor that instructs not only the maturation of already differentiated cardiomyocytes but also the induction and proliferation of cardiomyocytes from undifferentiated progenitors. Manipulation of the stiffness will help direct the production of functional cardiomyocytes en masse from stem cells for regenerative medicine purposes.

Uracil excision repair in Mycobacterium tuberculosis cell-free extracts.

Science.gov (United States)

Kumar, Pradeep; Bharti, Sanjay Kumar; Varshney, Umesh

2011-05-01

Uracil excision repair is ubiquitous in all domains of life and initiated by uracil DNA glycosylases (UDGs) which excise the promutagenic base, uracil, from DNA to leave behind an abasic site (AP-site). Repair of the resulting AP-sites requires an AP-endonuclease, a DNA polymerase, and a DNA ligase whose combined activities result in either short-patch or long-patch repair. Mycobacterium tuberculosis, the causative agent of tuberculosis, has an increased risk of accumulating uracils because of its G + C-rich genome, and its niche inside host macrophages where it is exposed to reactive nitrogen and oxygen species, two major causes of cytosine deamination (to uracil) in DNA. In vitro assays to study DNA repair in this important human pathogen are limited. To study uracil excision repair in mycobacteria, we have established assay conditions using cell-free extracts of M. tuberculosis and M. smegmatis (a fast-growing mycobacterium) and oligomer or plasmid DNA substrates. We show that in mycobacteria, uracil excision repair is completed primarily via long-patch repair. In addition, we show that M. tuberculosis UdgB, a newly characterized family 5 UDG, substitutes for the highly conserved family 1 UDG, Ung, thereby suggesting that UdgB might function as backup enzyme for uracil excision repair in mycobacteria. Copyright © 2011 Elsevier Ltd. All rights reserved.

Stem Cells in Tissue Repair and Regeneration

OpenAIRE

Falanga, Vincent

2012-01-01

The field of tissue repair and wound healing has blossomed in the last 30 years. We have gone from recombinant growth factors, to living tissue engineering constructs, to stem cells. The task now is to pursue true regeneration, thus achieving full restoration of structures and their function.

Repair-dependent cell radiation survival and transformation: an integrated theory

International Nuclear Information System (INIS)

Sutherland, John C

2014-01-01

The repair-dependent model of cell radiation survival is extended to include radiation-induced transformations. The probability of transformation is presumed to scale with the number of potentially lethal damages that are repaired in a surviving cell or the interactions of such damages. The theory predicts that at doses corresponding to high survival, the transformation frequency is the sum of simple polynomial functions of dose; linear, quadratic, etc, essentially as described in widely used linear-quadratic expressions. At high doses, corresponding to low survival, the ratio of transformed to surviving cells asymptotically approaches an upper limit. The low dose fundamental- and high dose plateau domains are separated by a downwardly concave transition region. Published transformation data for mammalian cells show the high-dose plateaus predicted by the repair-dependent model for both ultraviolet and ionizing radiation. For the neoplastic transformation experiments that were analyzed, the data can be fit with only the repair-dependent quadratic function. At low doses, the transformation frequency is strictly quadratic, but becomes sigmodial over a wider range of doses. Inclusion of data from the transition region in a traditional linear-quadratic analysis of neoplastic transformation frequency data can exaggerate the magnitude of, or create the appearance of, a linear component. Quantitative analysis of survival and transformation data shows good agreement for ultraviolet radiation; the shapes of the transformation components can be predicted from survival data. For ionizing radiations, both neutrons and x-rays, survival data overestimate the transforming ability for low to moderate doses. The presumed cause of this difference is that, unlike UV photons, a single x-ray or neutron may generate more than one lethal damage in a cell, so the distribution of such damages in the population is not accurately described by Poisson statistics. However, the complete

Meta-Analysis of Cell-based CaRdiac stUdiEs (ACCRUE) in patients with acute myocardial infarction based on individual patient data.

Science.gov (United States)

Gyöngyösi, Mariann; Wojakowski, Wojciech; Lemarchand, Patricia; Lunde, Ketil; Tendera, Michal; Bartunek, Jozef; Marban, Eduardo; Assmus, Birgit; Henry, Timothy D; Traverse, Jay H; Moyé, Lemuel A; Sürder, Daniel; Corti, Roberto; Huikuri, Heikki; Miettinen, Johanna; Wöhrle, Jochen; Obradovic, Slobodan; Roncalli, Jérome; Malliaras, Konstantinos; Pokushalov, Evgeny; Romanov, Alexander; Kastrup, Jens; Bergmann, Martin W; Atsma, Douwe E; Diederichsen, Axel; Edes, Istvan; Benedek, Imre; Benedek, Theodora; Pejkov, Hristo; Nyolczas, Noemi; Pavo, Noemi; Bergler-Klein, Jutta; Pavo, Imre J; Sylven, Christer; Berti, Sergio; Navarese, Eliano P; Maurer, Gerald

2015-04-10

The meta-Analysis of Cell-based CaRdiac study is the first prospectively declared collaborative multinational database, including individual data of patients with ischemic heart disease treated with cell therapy. We analyzed the safety and efficacy of intracoronary cell therapy after acute myocardial infarction (AMI), including individual patient data from 12 randomized trials (ASTAMI, Aalst, BOOST, BONAMI, CADUCEUS, FINCELL, REGENT, REPAIR-AMI, SCAMI, SWISS-AMI, TIME, LATE-TIME; n=1252). The primary end point was freedom from combined major adverse cardiac and cerebrovascular events (including all-cause death, AMI recurrance, stroke, and target vessel revascularization). The secondary end point was freedom from hard clinical end points (death, AMI recurrence, or stroke), assessed with random-effects meta-analyses and Cox regressions for interactions. Secondary efficacy end points included changes in end-diastolic volume, end-systolic volume, and ejection fraction, analyzed with random-effects meta-analyses and ANCOVA. We reported weighted mean differences between cell therapy and control groups. No effect of cell therapy on major adverse cardiac and cerebrovascular events (14.0% versus 16.3%; hazard ratio, 0.86; 95% confidence interval, 0.63-1.18) or death (1.4% versus 2.1%) or death/AMI recurrence/stroke (2.9% versus 4.7%) was identified in comparison with controls. No changes in ejection fraction (mean difference: 0.96%; 95% confidence interval, -0.2 to 2.1), end-diastolic volume, or systolic volume were observed compared with controls. These results were not influenced by anterior AMI location, reduced baseline ejection fraction, or the use of MRI for assessing left ventricular parameters. This meta-analysis of individual patient data from randomized trials in patients with recent AMI revealed that intracoronary cell therapy provided no benefit, in terms of clinical events or changes in left ventricular function. URL: http://www.clinicaltrials.gov. Unique

Effects of cell-to-collagen ratio in stem cell-seeded constructs for Achilles tendon repair.

Science.gov (United States)

Juncosa-Melvin, Natalia; Boivin, Gregory P; Galloway, Marc T; Gooch, Cindi; West, John R; Butler, David L

2006-04-01

The objective of the present study was to test the hypotheses that implantation of cell-seeded constructs in a rabbit Achilles tendon defect model would 1) improve repair biomechanics and matrix organization and 2) result in higher failure forces than measured in vivo forces in normal rabbit Achilles tendon (AT) during an inclined hopping activity. Autogenous tissue-engineered constructs were fabricated in culture between posts in the wells of silicone dishes at four cell-to-collagen ratios by seeding mesenchymal stem cells (MSC) from 18 adult rabbits at each of two seeding densities (0.1 x 10(6) and 1 x 10(6) cell/mL) in each of two collagen concentrations (1.3 and 2.6 mg/mL). After 5 days of contraction, constructs having the two highest ratios (0.4 and 0.8 M/mg) were damaged by excessive cell traction forces and could not be used in subsequent in vivo studies. Constructs at the lower ratios (0.04 and 0.08 M/mg) were implanted in bilateral, 2 cm long gap defects in the rabbit's lateral Achilles tendon. At 12 weeks after surgery, both repair tissues were isolated and either failed in tension (n = 13) to determine their biomechanical properties or submitted for histological analysis (n = 5). No significant differences were observed in any structural or mechanical properties or in histological appearance between the two repair conditions. However, the average maximum force and maximum stress of these repairs achieved 50 and 85% of corresponding values for the normal AT and exceeded the largest peak in vivo forces (19% of failure) previously recorded in the rabbit AT. Average stiffness and modulus were 60 and 85% of normal values, respectively. New constructs with lower cell densities and higher scaffold stiffness that do not excessively contract and tear in culture and that further improve the repair stiffness needed to withstand various levels of expected in vivo loading are currently being investigated.

Repair of sublethal damage in mammalian cells irradiated at ultrahigh dose rates

International Nuclear Information System (INIS)

Gerweck, L.E.; Epp, E.R.; Michaels, H.B.; Ling, C.C.; Peterson, E.C.

1979-01-01

The lethal response of asynchronous Chinese hamster ovary (CHO) cells exposed to single and split doses of radiation at conventional or ultrahigh dose rates has been examined to determine whether repair of sublethal damage occurs in cells irradiated at ultrahigh dose rates. The high-intensity irradiations were performed with electrons delivered in single 3-nsec pulses from a 600-kV field emission source under medium-removed, thin-layer conditions. Conventional dose-rate experiments were done under identical thin-layer conditions with 50-kVp x rays, or under full-medium conditions with 280-kVp x rays. Oxygenated cells were irradiated and maintained at 22 to 24 0 C between exposures. Survival did not increase as the time between two doses of pulsed electrons increased from 0 to 4 min, indicating no evidence of fast repair. However, increased survival was observed when 30 to 90 min was allowed to elapse between the split doses. The half-time for maximum repair was approx. = 30 min irrespective of the exposure conditions and radiation modality used. Observed repair ratios increased from approx. = 2 to 4 as the single-dose surviving fraction decreased from 10 -2 to 5 x 10 -4 . Over this survival range the repair ratios, measured at the same value of surviving fraction, were independent of dose rate. The observed repair ratios imply that the shoulder regions of the nonfractionated x-ray and pulsed-electron survival curves were not completely restored between the split doses. However, the fraction of the shoulder restored between split doses of radiation was dose-rate-independent. It is concluded that sublethal damage can be repaired in oxygenated CHO cells irradiated at dose rates of the order of 10 11 rad/sec

Localization of ultraviolet-induced excision repair in the nucleus and the distribution of repair events in higher order chromatin loops in mammalian cells

Energy Technology Data Exchange (ETDEWEB)

Mullenders, L.H.F.; Zeeland, A.A. van; Natarajan, A.T.

1987-01-01

Several lines of evidence indicate that eukaryotic DNA is arranged in highly supercoiled domains or loops, and that the repeating loops are constrained by attachment to a nuclear skeletal structure termed the nuclear matrix. We have investigated whether the repair of DNA damage occurs in the nuclear matrix compartment. Normal human fibroblasts, ultraviolet (u.v.)-irradiated with 30 J m/sup -2/ and post-u.v. incubated in the presence of hydroxyurea, did not show any evidence for the occurrence of repair synthesis at the nuclear matrix. 5 J m/sup -2/ repair synthesis seems to initiate at the nuclear matrix, although only part of the total repair could be localized there. In u.v.-irradiated (30 J m/sup -2/) normal human fibroblast post-u.v. incubated in the presence of hydroxyurea and arabinsosylcytosine for 2h, multiple single-stranded regions are generated in a DNA loop as a result of the inhibition of the excision repair process. Preferential repair of certain domains in the chromatin was shown to occur in xeroderma pigmentosum cells of complementation group C (XP-C) in contrast to XP-D cells and Syrian hamster embryonic cells.

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

International Nuclear Information System (INIS)

Gustafsson, Ann-Sofie; Abramenkovs, Andris; Stenerlöw, Bo

2014-01-01

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

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

Repair capability of mammalian cell fractions demonstrated using infectivity of bacteriophage DNA

International Nuclear Information System (INIS)

Lai, S.P.; Lytle, C.D.; Benane, S.G.

1976-01-01

Extracts of Potoroo kidney cells (PtK2) were examined for ability to provide a repair function in vitro. The biological activity (infectivity) of uv-irradiated replicative form (RF) DNA of bacteriophage phiX174 was restored during incubation of the DNA with a nuclear extract but not with a cytoplasmic extract. The infectivity of the RF-DNA was determined in spheroplasts of E. coli C/sub s/, which is HCR - . This system for biological assay of uv-irradiated DNA repaired in vitro may be used to complement biochemical and biophysical investigations of molecular repair mechanisms in mammalian cells

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

International Nuclear Information System (INIS)

Thompson, L.H.; Salazar, E.P.; Brookman, K.W.; Collins, C.C.; Stewart, S.A.; Busch, D.B.; Weber, C.A.

1986-01-01

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

Cardiac arrest due to hyperkalemia following irradiated packed red cells transfusion

Energy Technology Data Exchange (ETDEWEB)

Miyazawa, Kazuharu [Yamamoto-kumiai General Hospital, Noshiro, Akita (Japan); Ohta, Sukejuurou; Kojima, Yukiko; Mizunuma, Takahide; Nishikawa, Toshiaki

1998-11-01

We describe two cases of cardiac arrest due to hyperkalemia following transfusion of irradiated packed red cells. Case 1: Because sudden, rapid and massive hemorrage occurred in a 69-year-old male patient undergoing the left lobectomy of the liver, 8 units of irradiated packed red cells were rapidly transfused, the patient developed cardiac arrest. Serum kalium concentration after transfusion was 7.6 mEq/l. Case 2: A 7-month-old girl scheduled for closure of a ventricular septal defect, developed cardiac arrest due to hyperkalemia at the start of cardiopulmonary bypass. The extracorporeal circuit was primed with 6 units of irradiated packed red blood cells. Serum kalium concentration immediately after the start of cardiopulmonary bypass was 10.6 mEq/l. Analysis of kalium concentration in the pilot tubes of the same packs revealed 56-61 mEq/l. These case reports suggest that fresh irradiated packed red cells should be transfused during massive bleeding and for pediatric patients to prevent severe hyperkalemia. (author)

Revealing new mouse epicardial cell markers through transcriptomics.

Directory of Open Access Journals (Sweden)

Lars Bochmann

2010-06-01

Full Text Available The epicardium has key functions during myocardial development, by contributing to the formation of coronary endothelial and smooth muscle cells, cardiac fibroblasts, and potentially cardiomyocytes. The epicardium plays a morphogenetic role by emitting signals to promote and maintain cardiomyocyte proliferation. In a regenerative context, the adult epicardium might comprise a progenitor cell population that can be induced to contribute to cardiac repair. Although some genes involved in epicardial function have been identified, a detailed molecular profile of epicardial gene expression has not been available.Using laser capture microscopy, we isolated the epicardial layer from the adult murine heart before or after cardiac infarction in wildtype mice and mice expressing a transgenic IGF-1 propeptide (mIGF-1 that enhances cardiac repair, and analyzed the transcription profile using DNA microarrays.Expression of epithelial genes such as basonuclin, dermokine, and glycoprotein M6A are highly enriched in the epicardial layer, which maintains expression of selected embryonic genes involved in epicardial development in mIGF-1 transgenic hearts. After myocardial infarct, a subset of differentially expressed genes are down-regulated in the epicardium representing an epicardium-specific signature that responds to injury.This study presents the description of the murine epicardial transcriptome obtained from snap frozen tissues, providing essential information for further analysis of this important cardiac cell layer.

The Origin of Human Mesenchymal Stromal Cells Dictates Their Reparative Properties

DEFF Research Database (Denmark)

Naftali-Shani, Nili; Itzhaki-Alfia, Ayelet; Landa-Rouben, Natalie

2013-01-01

Human mesenchymal stromal cells (hMSCs) from adipose cardiac tissue have attracted considerable interest in regard to cell-based therapies. We aimed to test the hypothesis that hMSCs from the heart and epicardial fat would be better cells for infarct repair....

GPR30 decreases cardiac chymase/angiotensin II by inhibiting local mast cell number

International Nuclear Information System (INIS)

Zhao, Zhuo; Wang, Hao; Lin, Marina; Groban, Leanne

2015-01-01

Chronic activation of the novel estrogen receptor GPR30 by its agonist G1 mitigates the adverse effects of estrogen (E2) loss on cardiac structure and function. Using the ovariectomized (OVX) mRen2.Lewis rat, an E2-sensitive model of diastolic dysfunction, we found that E2 status is inversely correlated with local cardiac angiotensin II (Ang II) levels, likely via Ang I/chymase-mediated production. Since chymase is released from cardiac mast cells during stress (e.g., volume/pressure overload, inflammation), we hypothesized that GPR30-related cardioprotection after E2 loss might occur through its opposing actions on cardiac mast cell proliferation and chymase production. Using real-time quantitative PCR, immunohistochemistry, and immunoblot analysis, we found mast cell number, chymase expression, and cardiac Ang II levels were significantly increased in the hearts of OVX-compared to ovary-intact mRen2.Lewis rats and the GPR30 agonist G1 (50 mg/kg/day, s.c.) administered for 2 weeks limited the adverse effects of estrogen loss. In vitro studies revealed that GPR30 receptors are expressed in the RBL-2H3 mast cell line and G1 inhibits serum-induced cell proliferation in a dose-dependent manner, as determined by cell counting, BrdU incorporation assay, and Ki-67 staining. Using specific antagonists to estrogen receptors, blockage of GPR30, but not ERα or ERβ, attenuated the inhibitory effects of estrogen on BrdU incorporation in RBL-2H3 cells. Further study of the mechanism underlying the effect on cell proliferation showed that G1 inhibits cyclin-dependent kinase 1 (CDK1) mRNA and protein expression in RBL-2H3 cells in a dose-dependent manner. - Highlights: • GPR30 activation limits mast cell number in hearts from OVX mRen2.Lewis rats. • GPR30 activation decreases cardiac chymase/angiotensin II after estrogen loss. • GPR30 activation inhibits RBL-2H3 mast cell proliferation and CDK1 expression

GPR30 decreases cardiac chymase/angiotensin II by inhibiting local mast cell number

Energy Technology Data Exchange (ETDEWEB)

Zhao, Zhuo [Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27159-1009 (United States); Department of Cardiology, Jinan Central Hospital, Affiliated with Shandong University, 105 Jiefang Road, Jinan, 250013 (China); Wang, Hao; Lin, Marina [Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27159-1009 (United States); Groban, Leanne, E-mail: lgroban@wakehealth.edu [Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27159-1009 (United States); Hypertension and Vascular Disease Center, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 (United States); Office of Women in Medicine and Science, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 (United States)

2015-03-27

Chronic activation of the novel estrogen receptor GPR30 by its agonist G1 mitigates the adverse effects of estrogen (E2) loss on cardiac structure and function. Using the ovariectomized (OVX) mRen2.Lewis rat, an E2-sensitive model of diastolic dysfunction, we found that E2 status is inversely correlated with local cardiac angiotensin II (Ang II) levels, likely via Ang I/chymase-mediated production. Since chymase is released from cardiac mast cells during stress (e.g., volume/pressure overload, inflammation), we hypothesized that GPR30-related cardioprotection after E2 loss might occur through its opposing actions on cardiac mast cell proliferation and chymase production. Using real-time quantitative PCR, immunohistochemistry, and immunoblot analysis, we found mast cell number, chymase expression, and cardiac Ang II levels were significantly increased in the hearts of OVX-compared to ovary-intact mRen2.Lewis rats and the GPR30 agonist G1 (50 mg/kg/day, s.c.) administered for 2 weeks limited the adverse effects of estrogen loss. In vitro studies revealed that GPR30 receptors are expressed in the RBL-2H3 mast cell line and G1 inhibits serum-induced cell proliferation in a dose-dependent manner, as determined by cell counting, BrdU incorporation assay, and Ki-67 staining. Using specific antagonists to estrogen receptors, blockage of GPR30, but not ERα or ERβ, attenuated the inhibitory effects of estrogen on BrdU incorporation in RBL-2H3 cells. Further study of the mechanism underlying the effect on cell proliferation showed that G1 inhibits cyclin-dependent kinase 1 (CDK1) mRNA and protein expression in RBL-2H3 cells in a dose-dependent manner. - Highlights: • GPR30 activation limits mast cell number in hearts from OVX mRen2.Lewis rats. • GPR30 activation decreases cardiac chymase/angiotensin II after estrogen loss. • GPR30 activation inhibits RBL-2H3 mast cell proliferation and CDK1 expression.

Mesenchymal Stem Cells in Tissue Repair

Directory of Open Access Journals (Sweden)

Amy M DiMarino

2013-09-01

Full Text Available The advent of mesenchymal stem cell (MSC based therapies for clinical therapeutics has been an exciting and new innovation for the treatment of a variety of diseases associated with inflammation, tissue damage and subsequent regeneration and repair. Application-based ability to measure MSC potency and fate of the cells post-MSC therapy are the variables that confound the use of MSCs therapeutics in human diseases. An evaluation of MSC function and applications with attention to detail in the preparation as well as quality control (QC and quality assurance (QA are only as good as the assays that are developed. In vivo measures of efficacy and potency require an appreciation of the overall pathophysiology of the model and standardization of outcome measures. The new concepts of how MSC’s participate in the tissue regeneration and wound repair process and further, how this is impacted by estimates of efficacy and potency Are important new topics. In this regard,,, this chapter will review some of the in vitro and in vivo assays for MSC function and activity and their application to the clinical arena.

Human cardiac-derived adherent proliferating cells reduce murine acute Coxsackievirus B3-induced myocarditis.

Directory of Open Access Journals (Sweden)

Kapka Miteva

Full Text Available BACKGROUND: Under conventional heart failure therapy, inflammatory cardiomyopathy typically has a progressive course, indicating a need for alternative therapeutic strategies to improve long-term outcomes. We recently isolated and identified novel cardiac-derived cells from human cardiac biopsies: cardiac-derived adherent proliferating cells (CAPs. They have similarities with mesenchymal stromal cells, which are known for their anti-apoptotic and immunomodulatory properties. We explored whether CAPs application could be a novel strategy to improve acute Coxsackievirus B3 (CVB3-induced myocarditis. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the safety of our approach, we first analyzed the expression of the coxsackie- and adenovirus receptor (CAR and the co-receptor CD55 on CAPs, which are both required for effective CVB3 infectivity. We could demonstrate that CAPs only minimally express both receptors, which translates to minimal CVB3 copy numbers, and without viral particle release after CVB3 infection. Co-culture of CAPs with CVB3-infected HL-1 cardiomyocytes resulted in a reduction of CVB3-induced HL-1 apoptosis and viral progeny release. In addition, CAPs reduced CD4 and CD8 T cell proliferation. All CAPs-mediated protective effects were nitric oxide- and interleukin-10-dependent and required interferon-γ. In an acute murine model of CVB3-induced myocarditis, application of CAPs led to a decrease of cardiac apoptosis, cardiac CVB3 viral load and improved left ventricular contractility parameters. This was associated with a decline in cardiac mononuclear cell activity, an increase in T regulatory cells and T cell apoptosis, and an increase in left ventricular interleukin-10 and interferon-γ mRNA expression. CONCLUSIONS: We conclude that CAPs are a unique type of cardiac-derived cells and promising tools to improve acute CVB3-induced myocarditis.

Modified nuss procedure in concurrent repair of pectus excavatum and open heart surgery.

Science.gov (United States)

Sacco Casamassima, Maria Grazia; Wong, Ling Ling; Papandria, Dominic; Abdullah, Fizan; Vricella, Luca A; Cameron, Duke E; Colombani, Paul M

2013-03-01

Pectus excavatum (PE) can be associated with congenital and acquired cardiac disorders that also require surgical repair. The timing and specific surgical technique for repair of PE remains controversial. The present study reports the experience of combined repair of PE and open heart surgery at Johns Hopkins Hospital. A retrospective case review was conducted of all patients who presented for repair of PE deformity while undergoing concurrent open heart surgery from 1998 through 2011. A total of 9 patients met inclusion criteria. All patients had a connective tissue disorder. Repair of PE was performed by modified Nuss technique after completion of the cardiac procedure, performed through a median sternotomy. Open heart procedures were either aortic root replacement or mitral valvuloplasty. Eight patients had bar removal after an average period of 30.3 months. No PE recurrence, bar displacement, or upper sternal depression was reported in 7 patients. Postoperatively, 1 patient exhibited pectus carinatum after a separate spinal fusion surgery for scoliosis. One patient died of unrelated cardiac complications before bar removal. Simultaneous repair of PE and open heart surgery is safe and effective. We recommend that the decision to perform a single-stage versus a multistage procedure should be reserved until after the cardiac procedure has been completed. In such cases, the Nuss technique allows for correction of the pectus deformity with good long-term cosmetic and functional results. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

DNA repair in human cells: Methods for the determination of calmodulin involvement

International Nuclear Information System (INIS)

Charp, P.A.

1987-01-01

Exposure of DNA to either physical or chemical agents can result in the formation of a number of different lesions which must be repaired enzymatically in order for DNA to carry on normal replication and transcription. In most cases, the enzymes involved in this repair of damaged DNA include endonucleases, exonucleases, glycosylases, polymerases, and ligases. Each group of enzymes is involved in precise steps in DNA repair. Exposure to physical agents such as ultraviolet light (UV) at a wavelength of 254 nm is repaired by two distinct and different mechanisms. One mode of enzymatic repair of pyrimidine dimers is accomplished in situ by photoreactivation of UV-induced pyrimidine dimers by photoreactivating light. The second mode of enzymatic repair is the excision repair of pyrimidine dimers involving several different enzymes including endonuclease, exonuclease, and DNA ligase. A summary of the sequence of enzymatic steps involved is shown. It has been observed that specific drugs which bind to and alter the action of calmodulin in cells block DNA synthesis. This suggests that calmodulin may play a role both in normal DNA replication and repair. Others using an indirect method measuring the degree of DNA nucleoid sedimentation, showed that the specific anti-calmodulin agent W-13 slowed the rate of DNA repair. Others showed that DNA synthesis in T51B rat liver cells could be blocked with the addition of either chlorpromazine or trifluoperazine

Accordion-like honeycombs for tissue engineering of cardiac anisotropy

Science.gov (United States)

Engelmayr, George C.; Cheng, Mingyu; Bettinger, Christopher J.; Borenstein, Jeffrey T.; Langer, Robert; Freed, Lisa E.

2008-12-01

Tissue-engineered grafts may be useful in myocardial repair; however, previous scaffolds have been structurally incompatible with recapitulating cardiac anisotropy. Here, we use microfabrication techniques to create an accordion-like honeycomb microstructure in poly(glycerol sebacate), which yields porous, elastomeric three-dimensional (3D) scaffolds with controllable stiffness and anisotropy. Accordion-like honeycomb scaffolds with cultured neonatal rat heart cells demonstrated utility through: (1) closely matched mechanical properties compared to native adult rat right ventricular myocardium, with stiffnesses controlled by polymer curing time; (2) heart cell contractility inducible by electric field stimulation with directionally dependent electrical excitation thresholds (pthe formation of grafts with aligned heart cells and mechanical properties more closely resembling native myocardium.

Induced pluripotent stem cell derived cardiomyocytes as models for cardiac arrhythmias

Directory of Open Access Journals (Sweden)

Maaike eHoekstra

2012-08-01

Full Text Available Cardiac arrhythmias are a major cause of morbidity and mortality. In younger patients, the majority of sudden cardiac deaths have an underlying Mendelian genetic cause. Over the last 15 years, enormous progress has been made in identifying the distinct clinical phenotypes and in studying the basic cellular and genetic mechanisms associated with the primary Mendelian (monogenic arrhythmia syndromes. Investigation of the electrophysiological consequences of an ion channel mutation is ideally done in the native cardiomyocyte environment. However, the majority of such studies so far have relied on heterologous expression systems in which single ion channel genes are expressed in non-cardiac cells. In some cases, transgenic mouse models haven been generated, but these also have significant shortcomings, primarily related to species differences.The discovery that somatic cells can be reprogrammed to pluripotency as induced pluripotent stem cells (iPSC has generated much interest since it presents an opportunity to generate patient- and disease-specific cell lines from which normal and diseased human cardiomyocytes can be obtained These genetically diverse human model systems can be studied in vitro and used to decipher mechanisms of disease and identify strategies and reagents for new therapies. Here we review the present state of the art with respect to cardiac disease models already generated using IPSC technology and which have been (partially characterized.Human iPSC (hiPSC models have been described for the cardiac arrhythmia syndromes, including LQT1, LQT2, LQT3-Brugada Syndrome, LQT8/Timothy syndrome and catecholaminergic polymorphic ventricular tachycardia. In most cases, the hiPSC-derived cardiomyoctes recapitulate the disease phenotype and have already provided opportunities for novel insight into cardiac pathophysiology. It is expected that the lines will be useful in the development of pharmacological agents for the management of these

Potential of Bioactive Glasses for Cardiac and Pulmonary Tissue Engineering

Directory of Open Access Journals (Sweden)

Saeid Kargozar

2017-12-01

Full Text Available Repair and regeneration of disorders affecting cardiac and pulmonary tissues through tissue-engineering-based approaches is currently of particular interest. On this matter, different families of bioactive glasses (BGs have recently been given much consideration with respect to treating refractory diseases of these tissues, such as myocardial infarction. The inherent properties of BGs, including their ability to bond to hard and soft tissues, to stimulate angiogenesis, and to elicit antimicrobial effects, along with their excellent biocompatibility, support these newly proposed strategies. Moreover, BGs can also act as a bioactive reinforcing phase to finely tune the mechanical properties of polymer-based constructs used to repair the damaged cardiac and pulmonary tissues. In the present study, we evaluated the potential of different forms of BGs, alone or in combination with other materials (e.g., polymers, in regards to repair and regenerate injured tissues of cardiac and pulmonary systems.

Repair and cell-cycle response in cells exposed to environmental biohazards. Comprehensive project report, June 1, 1979-May 31, 1982

International Nuclear Information System (INIS)

Billen, D.

1982-01-01

Agents which cause damage to DNA leading to inhibition of DNA synthesis or faulty DNA replication or repair may cause cell death or mutation. Many organisms possess the ability to circumvent some or all of this DNA damage. Many DNA mutants of E. coli and B. subtilis provide a genetic approach to measuring the role of individual components of the DNA repair and replicative system. The information obtained with prokaryotes provides leads to assess the details of DNA repair and replication in mammalian systems including man. Escherichia coli cells treated with a low concentration of toluene become permeable to a variety of compounds, including the precursors and cofactors necessary for DNA synthesis. By their manipulation various aspects of DNA replication and repair can be selectively emphasized. Observations made by use of this system include: (1) Repair synthesis induced by x irradiation or exposure to alkylating chemicals of toluene-treated cells is more extensive if polynucleotide ligase is inhibited. (2) DNA replication in E. coli is carried out by DNA polymerase III. The replication of DNA is strongly inhibited by methylmethansulfonate, N-methyl-N-nitrosourea, and N-methyl-N'-nitro-N-nitrosoguanidine. (3) Using a po1A1 po1B100 dnaB (po1I - , po1II - , po1III + ) mutant of E. coli, it was demonstrated that the dnaB gene product is not necessary for Po1III directed repair synthesis. (4) The physiological stage of cells and tissues affects their response to environmental hazards. (5) Procedures for permeabilizing mammalian cells have been developed or further refined; and (6) In earlier studies involving both alkylating agents and x rays, it was observed that the number of DNA single-strand breaks increased with dose along with repair synthesis. It appears that non-repaired sites do not serve as primer ends for Po1I-dependent repair synthesis in toluene-treated cells

Inhibition of X-ray induced DNA strand break repair in polyamine-depleted HeLa cells

Energy Technology Data Exchange (ETDEWEB)

Snyder, R.D.

1989-05-01

Treatment of HeLa cells with the polyamine biosynthesis inhibitors, alpha-difluoromethylornithine (DFMO) or methylglyoxal bis(guanylhydrazone) (MGBG), results in, depending on the conditions, partial or complete depletion of the cellular polyamines: putrescine, spermidine and spermine. In this compromised state cells exhibited a distinct deficiency in repair of X-ray-induced DNA strand breaks. The half-time for return of normal DNA sedimentation following 1.6 Gy was 9.5 min for untreated control cells and 22, 32 and 50 min for cells treated with MGBG, DFMO+MGBG and DFMO, respectively. Normal repair kinetics were restored to these cells upon a short incubation in media containing all three polyamines. The rapid early phase of repair following higher X-ray doses (16 Gy) was also delayed in polyamine-depleted cells but later repair occurring 1-4 h post-irradiation, representing chromatin reconstitution, was apparently normal. (author).

Inhibition of X-ray induced DNA strand break repair in polyamine-depleted HeLa cells

International Nuclear Information System (INIS)

Snyder, R.D.

1989-01-01

Treatment of HeLa cells with the polyamine biosynthesis inhibitors, alpha-difluoromethylornithine (DFMO) or methylglyoxal bis(guanylhydrazone) (MGBG), results in, depending on the conditions, partial or complete depletion of the cellular polyamines: putrescine, spermidine and spermine. In this compromised state cells exhibited a distinct deficiency in repair of X-ray-induced DNA strand breaks. The half-time for return of normal DNA sedimentation following 1.6 Gy was 9.5 min for untreated control cells and 22, 32 and 50 min for cells treated with MGBG, DFMO+MGBG and DFMO, respectively. Normal repair kinetics were restored to these cells upon a short incubation in media containing all three polyamines. The rapid early phase of repair following higher X-ray doses (16 Gy) was also delayed in polyamine-depleted cells but later repair occurring 1-4 h post-irradiation, representing chromatin reconstitution, was apparently normal. (author)

Multiple repair pathways mediate tolerance to chemotherapeutic cross-linking agents in vertebrate cells.

Science.gov (United States)

Nojima, Kuniharu; Hochegger, Helfrid; Saberi, Alihossein; Fukushima, Toru; Kikuchi, Koji; Yoshimura, Michio; Orelli, Brian J; Bishop, Douglas K; Hirano, Seiki; Ohzeki, Mioko; Ishiai, Masamichi; Yamamoto, Kazuhiko; Takata, Minoru; Arakawa, Hiroshi; Buerstedde, Jean-Marie; Yamazoe, Mitsuyoshi; Kawamoto, Takuo; Araki, Kasumi; Takahashi, Jun A; Hashimoto, Nobuo; Takeda, Shunichi; Sonoda, Eiichiro

2005-12-15

Cross-linking agents that induce DNA interstrand cross-links (ICL) are widely used in anticancer chemotherapy. Yeast genetic studies show that nucleotide excision repair (NER), Rad6/Rad18-dependent postreplication repair, homologous recombination, and cell cycle checkpoint pathway are involved in ICL repair. To study the contribution of DNA damage response pathways in tolerance to cross-linking agents in vertebrates, we made a panel of gene-disrupted clones from chicken DT40 cells, each defective in a particular DNA repair or checkpoint pathway, and measured the sensitivities to cross-linking agents, including cis-diamminedichloroplatinum (II) (cisplatin), mitomycin C, and melphalan. We found that cells harboring defects in translesion DNA synthesis (TLS), Fanconi anemia complementation groups (FANC), or homologous recombination displayed marked hypersensitivity to all the cross-linking agents, whereas NER seemed to play only a minor role. This effect of replication-dependent repair pathways is distinctively different from the situation in yeast, where NER seems to play a major role in dealing with ICL. Cells deficient in Rev3, the catalytic subunit of TLS polymerase Polzeta, showed the highest sensitivity to cisplatin followed by fanc-c. Furthermore, epistasis analysis revealed that these two mutants work in the same pathway. Our genetic comprehensive study reveals a critical role for DNA repair pathways that release DNA replication block at ICLs in cellular tolerance to cross-linking agents and could be directly exploited in designing an effective chemotherapy.

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

Energy Technology Data Exchange (ETDEWEB)

Kashino, Genro [Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR (United Kingdom); Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Suzuki, Keiji [Division of Radiation Biology, Department of Radiology and Radiation Biology, Course of Life Sciences and Radiation Research, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521 (Japan); Matsuda, Naoki [Division of Radiation Biology and Protection, Center for Frontier Life Sciences, Nagasaki University, Nagasaki 852-8102 (Japan); Kodama, Seiji [Radiation Biology Laboratory, Radiation Research Center, Frontier Science Innovation Center, Organization for University-Industry-Government Cooperation, Osaka Prefecture University, 1-2 Gakuen-cho, Sakai, Osaka 599-8570 (Japan); Ono, Koji [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, 2-1010 Asashiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Watanabe, Masami [Laboratory of Radiation Biology, Division of Radiation Life Science, Department of Radiation Life Science and Radiation Medical Science, Kyoto University Research Reactor Institute, 2-1010 Asashiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Prise, Kevin M [Gray Cancer Institute, P.O. Box 100, Mount Vernon Hospital, Northwood, Middlesex HA6 2JR (United Kingdom) and Centre for Cancer Research and Cell Biology, Queen' s University Belfast, Lisburn Road, Belfast BT9 7AB (United Kingdom)]. E-mail: prise@gci.ac.uk

2007-06-01

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.

DNA damage and repair in rabbit lens epithelial cells following UVA radiation

International Nuclear Information System (INIS)

Sidjanin, Duska; Zigman, Seymour; Reddan, John

1993-01-01

Since ultraviolet light may be a contributing factor to cataractogenesis, we investigated the response of the lens epithelium, a potential target for UV insult, to UVA radiation. Cell survival and the induction and repair of DNA single-strand breaks (SSBs) were measured in cultured rabbit lens epithelial cells following UVA exposure. A 30 min exposure to UVA (180 KJ/m 2 ) induced measurable SSBs. An increase in UVA fluenced measurable SSBs. An increase in UVA fluence brought about an increase in UVA fluence brought about an increase in the number of DNA SSBs. Rejoining of SSBs were measured after the cells were irradiated in Tyrode's for 2 hrs and allowed to repair in the dark for 4 hrs at 36 o C in MEM containing 10% serum. Eighty percent of the DNA SSBs were repaired within 4 hrs as determined by analysis of the alkaline elution profile. The repair kinetics were biphasic with an initial fast and subsequently slower component. The results indicate that UVA can induce SSBs in lens-induced SSBs, and that UVA treatment can be toxic to the epithelium. (Author)

Carbon nanotube-incorporated collagen hydrogels improve cell alignment and the performance of cardiac constructs

Directory of Open Access Journals (Sweden)

Sun HY

2017-04-01

Full Text Available Hongyu Sun,* Jing Zhou,* Zhu Huang,* Linlin Qu,* Ning Lin,* Chengxiao Liang, Ruiwu Dai, Lijun Tang, Fuzhou Tian General Surgery Center, Chengdu Military General Hospital, Chengdu, China *These authors contributed equally to this work Abstract: Carbon nanotubes (CNTs provide an essential 2-D microenvironment for cardiomyocyte growth and function. However, it remains to be elucidated whether CNT nanostructures can promote cell–cell integrity and facilitate the formation of functional tissues in 3-D hydrogels. Here, single-walled CNTs were incorporated into collagen hydrogels to fabricate (CNT/Col hydrogels, which improved mechanical and electrical properties. The incorporation of CNTs (up to 1 wt% exhibited no toxicity to cardiomyocytes and enhanced cell adhesion and elongation. Through the use of immunohistochemical staining, transmission electron microscopy, and intracellular calcium-transient measurement, the incorporation of CNTs was found to improve cell alignment and assembly remarkably, which led to the formation of engineered cardiac tissues with stronger contraction potential. Importantly, cardiac tissues based on CNT/Col hydrogels were noted to have better functionality. Collectively, the incorporation of CNTs into the Col hydrogels improved cell alignment and the performance of cardiac constructs. Our study suggests that CNT/Col hydrogels offer a promising tissue scaffold for cardiac constructs, and might serve as injectable biomaterials to deliver cell or drug molecules for cardiac regeneration following myocardial infarction in the near future. Keywords: carbon nanotubes, collagen hydrogel, cardiac constructs, cell alignment, tissue functionality

Carbon nanotube-incorporated collagen hydrogels improve cell alignment and the performance of cardiac constructs

Science.gov (United States)

Sun, Hongyu; Zhou, Jing; Huang, Zhu; Qu, Linlin; Lin, Ning; Liang, Chengxiao; Dai, Ruiwu; Tang, Lijun; Tian, Fuzhou

2017-01-01

Carbon nanotubes (CNTs) provide an essential 2-D microenvironment for cardiomyocyte growth and function. However, it remains to be elucidated whether CNT nanostructures can promote cell–cell integrity and facilitate the formation of functional tissues in 3-D hydrogels. Here, single-walled CNTs were incorporated into collagen hydrogels to fabricate (CNT/Col) hydrogels, which improved mechanical and electrical properties. The incorporation of CNTs (up to 1 wt%) exhibited no toxicity to cardiomyocytes and enhanced cell adhesion and elongation. Through the use of immunohistochemical staining, transmission electron microscopy, and intracellular calcium-transient measurement, the incorporation of CNTs was found to improve cell alignment and assembly remarkably, which led to the formation of engineered cardiac tissues with stronger contraction potential. Importantly, cardiac tissues based on CNT/Col hydrogels were noted to have better functionality. Collectively, the incorporation of CNTs into the Col hydrogels improved cell alignment and the performance of cardiac constructs. Our study suggests that CNT/Col hydrogels offer a promising tissue scaffold for cardiac constructs, and might serve as injectable biomaterials to deliver cell or drug molecules for cardiac regeneration following myocardial infarction in the near future. PMID:28450785

Repairable-conditionally repairable damage model based on dual Poisson processes.

Science.gov (United States)

Lind, B K; Persson, L M; Edgren, M R; Hedlöf, I; Brahme, A

2003-09-01

The advent of intensity-modulated radiation therapy makes it increasingly important to model the response accurately when large volumes of normal tissues are irradiated by controlled graded dose distributions aimed at maximizing tumor cure and minimizing normal tissue toxicity. The cell survival model proposed here is very useful and flexible for accurate description of the response of healthy tissues as well as tumors in classical and truly radiobiologically optimized radiation therapy. The repairable-conditionally repairable (RCR) model distinguishes between two different types of damage, namely the potentially repairable, which may also be lethal, i.e. if unrepaired or misrepaired, and the conditionally repairable, which may be repaired or may lead to apoptosis if it has not been repaired correctly. When potentially repairable damage is being repaired, for example by nonhomologous end joining, conditionally repairable damage may require in addition a high-fidelity correction by homologous repair. The induction of both types of damage is assumed to be described by Poisson statistics. The resultant cell survival expression has the unique ability to fit most experimental data well at low doses (the initial hypersensitive range), intermediate doses (on the shoulder of the survival curve), and high doses (on the quasi-exponential region of the survival curve). The complete Poisson expression can be approximated well by a simple bi-exponential cell survival expression, S(D) = e(-aD) + bDe(-cD), where the first term describes the survival of undamaged cells and the last term represents survival after complete repair of sublethal damage. The bi-exponential expression makes it easy to derive D(0), D(q), n and alpha, beta values to facilitate comparison with classical cell survival models.

The localization of ultraviolet-induced excision repair in the nucleus and the distribution of repair events in higher order chromatin loops in mammalian cells

International Nuclear Information System (INIS)

Mullenders, L.H.F.; Zeeland, A.A. van; Natarajan, A.T.

1987-01-01

Several lines of evidence indicate that eukaryotic DNA is arranged in highly supercoiled domains or loops, and that the repeating loops are constrained by attachment to a nuclear skeletal structure termed the nuclear matrix. We have investigated whether the repair of DNA damage occurs in the nuclear matrix compartment. Normal human fibroblasts, ultraviolet (u.v.)-irradiated with 30 J m -2 and post-u.v. incubated in the presence of hydroxyurea, did not show any evidence for the occurrence of repair synthesis at the nuclear matrix. 5 J m -2 repair synthesis seems to initiate at the nuclear matrix, although only part of the total repair could be localized there. In u.v.-irradiated (30 J m -2 ) normal human fibroblast post-u.v. incubated in the presence of hydroxyurea and arabinsosylcytosine for 2h, multiple single-stranded regions are generated in a DNA loop as a result of the inhibition of the excision repair process. Preferential repair of certain domains in the chromatin was shown to occur in xeroderma pigmentosum cells of complementation group C (XP-C) in contrast to XP-D cells and Syrian hamster embryonic cells. (author)

Predictive factors for red blood cell transfusion in children undergoing noncomplex cardiac surgery.

Science.gov (United States)

Mulaj, Muj; Faraoni, David; Willems, Ariane; Sanchez Torres, Cristel; Van der Linden, Philippe

2014-08-01

Red blood cell (RBC) transfusion is frequently required in pediatric cardiac surgery and is associated with altered outcome and increased costs. Determining which factors predict transfusion in this context will enable clinicians to adopt strategies that will reduce the risk of RBC transfusion. This study aimed to assess predictive factors associated with RBC transfusion in children undergoing low-risk cardiac surgery with cardiopulmonary bypass (CPB). Children undergoing surgery to repair ventricular septal defect or atrioventricular septal defect from 2006 to 2011 were included in this retrospective study. Demography, preoperative laboratory testing, intraoperative data, and RBC transfusion were reviewed. Univariate and multivariate logistic regression analysis were used to define factors that were able to predict RBC transfusion. Then, we employed receiver operating characteristic analysis to design a predictive score. Among the 334 children included, 261 (78%) were transfused. Age (43 mL/kg), type of oxygenator used, minimal temperature reached during CPB (<32°C), and preoperative hematocrit (<34%) were independently associated with RBC transfusion in the studied population. A predictive score 2 or greater was the best predictor of RBC transfusion. The present study identified several factors that were significantly associated with perioperative RBC transfusion. Based on these factors, we designed a predictive score that can be used to develop a patient-based blood management program with the aim of reducing the incidence of RBC transfusion. Copyright © 2014 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Rho-associated kinase inhibitors promote the cardiac differentiation of embryonic and induced pluripotent stem cells.

Science.gov (United States)

Cheng, Ya-Ting; Yeih, Dong-Feng; Liang, Shu-Man; Chien, Chia-Ying; Yu, Yen-Ling; Ko, Bor-Sheng; Jan, Yee-Jee; Kuo, Cheng-Chin; Sung, Li-Ying; Shyue, Song-Kun; Chen, Ming-Fong; Yet, Shaw-Fang; Wu, Kenneth K; Liou, Jun-Yang

2015-12-15

Rho-associated kinase (ROCK) plays an important role in maintaining embryonic stem (ES) cell pluripotency. To determine whether ROCK is involved in ES cell differentiation into cardiac and hematopoietic lineages, we evaluated the effect of ROCK inhibitors, Y-27632 and fasudil on murine ES and induced pluripotent stem (iPS) cell differentiation. Gene expression levels were determined by real-time PCR, Western blot analysis and immunofluorescent confocal microscopy. Cell transplantation of induced differentiated cells were assessed in vivo in a mouse model (three groups, n=8/group) of acute myocardial infarction (MI). The cell engraftment was examined by immunohistochemical staining and the outcome was analyzed by echocardiography. Cells were cultured in hematopoietic differentiation medium in the presence or absence of ROCK inhibitor and colony formation as well as markers of ES, hematopoietic stem cells (HSC) and cells of cardiac lineages were analyzed. ROCK inhibition resulted in a drastic change in colony morphology accompanied by loss of hematopoietic markers (GATA-1, CD41 and β-Major) and expressed markers of cardiac lineages (GATA-4, Isl-1, Tbx-5, Tbx-20, MLC-2a, MLC-2v, α-MHC, cTnI and cTnT) in murine ES and iPS cells. Fasudil-induced cardiac progenitor (Mesp-1 expressing) cells were infused into a murine MI model. They engrafted into the peri-infarct and infarct regions and preserved left ventricular function. These findings provide new insights into the signaling required for ES cell differentiation into hematopoietic as well as cardiac lineages and suggest that ROCK inhibitors are useful in directing iPS cell differentiation into cardiac progenitor cells for cell therapy of cardiovascular diseases. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Left atrial appendages from adult hearts contain a reservoir of diverse cardiac progenitor cells.

Directory of Open Access Journals (Sweden)

Jussi V Leinonen

Full Text Available There is strong evidence supporting the claim that endogenous cardiac progenitor cells (CPCs are key players in cardiac regeneration, but the anatomic source and phenotype of the master cardiac progenitors remains uncertain. Our aim was to investigate the different cardiac stem cell populations in the left atrial appendage (LAA and their fates.We investigated the CPC content and profile of adult murine LAAs using immunohistochemistry and flow cytometry. We demonstrate that the LAA contains a large number of CPCs relative to other areas of the heart, representing over 20% of the total cell number. We grew two distinct CPC populations from the LAA by varying the degree of proteolysis. These differed by their histological location, surface marker profiles and growth dynamics. Specifically, CD45(pos cells grew with milder proteolysis, while CD45(neg cells grew mainly with more intense proteolysis. Both cell types could be induced to differentiate into cells with cardiomyocyte markers and organelles, albeit by different protocols. Many CD45(pos cells expressed CD45 initially and rapidly lost its expression while differentiating.Our results demonstrate that the left atrial appendage plays a role as a reservoir of multiple types of progenitor cells in murine adult hearts. Two different types of CPCs were isolated, differing in their epicardial-myocardial localization. Considering studies demonstrating layer-specific origins of different cardiac progenitor cells, our findings may shed light on possible pathways to study and utilize the diversity of endogenous progenitor cells in the adult heart.

Graphene Films Show Stable Cell Attachment and Biocompatibility with Electrogenic Primary Cardiac Cells

OpenAIRE

Kim, Taeyong; Kahng, Yung Ho; Lee, Takhee; Lee, Kwanghee; Kim, Do Han

2013-01-01

Graphene has attracted substantial attention due to its advantageous materialistic applicability. In the present study, we tested the biocompatibility of graphene films synthesized by chemical vapor deposition with electrogenic primary adult cardiac cells (cardiomyocytes) by measuring the cell properties such as cell attachment, survival, contractility and calcium transients. The results show that the graphene films showed stable cell attachment and excellent biocompatibility with the electro...

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.

More efficient repair of DNA double-strand breaks in skeletal muscle stem cells compared to their committed progeny.

Science.gov (United States)

Vahidi Ferdousi, Leyla; Rocheteau, Pierre; Chayot, Romain; Montagne, Benjamin; Chaker, Zayna; Flamant, Patricia; Tajbakhsh, Shahragim; Ricchetti, Miria

2014-11-01

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. Copyright © 2014. Published by Elsevier B.V.

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

International Nuclear Information System (INIS)

Bajinskis, Ainars; Olsson, Gunilla; Harms-Ringdahl, Mats

2012-01-01

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 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.

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.

Science.gov (United States)

Bajinskis, Ainars; Olsson, Gunilla; Harms-Ringdahl, Mats

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(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. Copyright © 2011 Elsevier B.V. All rights reserved.

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.

Slow mitochondrial repair of 5'-AMP renders mtDNA susceptible to damage in APTX deficient cells

DEFF Research Database (Denmark)

Akbari, Mansour; Sykora, Peter; Bohr, Vilhelm A

2015-01-01

deficient cells. Moreover, the removal of 5'-AMP from DNA was significantly slower in the mitochondrial extracts from human cell lines and mouse tissues compared with their corresponding nuclear extracts. These results suggest that, contrary to nuclear DNA repair, mitochondrial DNA repair is not able...... elucidated. Here, we monitored the repair of 5'-AMP DNA damage in nuclear and mitochondrial extracts from human APTX(+/+) and APTX(-/-) cells. The efficiency of repair of 5'-AMP DNA was much lower in mitochondrial than in nuclear protein extracts, and resulted in persistent DNA repair intermediates in APTX......Aborted DNA ligation events in eukaryotic cells can generate 5'-adenylated (5'-AMP) DNA termini that can be removed from DNA by aprataxin (APTX). Mutations in APTX cause an inherited human disease syndrome characterized by early-onset progressive ataxia with ocular motor apraxia (AOA1). APTX...

Adipose, Bone Marrow and Synovial Joint-Derived Mesenchymal Stem Cells for Cartilage Repair

Science.gov (United States)

Fellows, Christopher R.; Matta, Csaba; Zakany, Roza; Khan, Ilyas M.; Mobasheri, Ali

2016-01-01

Current cell-based repair strategies have proven unsuccessful for treating cartilage defects and osteoarthritic lesions, consequently advances in innovative therapeutics are required and mesenchymal stem cell-based (MSC) therapies are an expanding area of investigation. MSCs are capable of differentiating into multiple cell lineages and exerting paracrine effects. Due to their easy isolation, expansion, and low immunogenicity, MSCs are an attractive option for regenerative medicine for joint repair. Recent studies have identified several MSC tissue reservoirs including in adipose tissue, bone marrow, cartilage, periosteum, and muscle. MSCs isolated from these discrete tissue niches exhibit distinct biological activities, and have enhanced regenerative potentials for different tissue types. Each MSC type has advantages and disadvantages for cartilage repair and their use in a clinical setting is a balance between expediency and effectiveness. In this review we explore the challenges associated with cartilage repair and regeneration using MSC-based cell therapies and provide an overview of phenotype, biological activities, and functional properties for each MSC population. This paper also specifically explores the therapeutic potential of each type of MSC, particularly focusing on which cells are capable of producing stratified hyaline-like articular cartilage regeneration. Finally we highlight areas for future investigation. Given that patients present with a variety of problems it is unlikely that cartilage regeneration will be a simple “one size fits all,” but more likely an array of solutions that need to be applied systematically to achieve regeneration of a biomechanically competent repair tissue. PMID:28066501

Adipose, Bone Marrow and Synovial Joint-derived Mesenchymal Stem Cells for Cartilage Repair

Directory of Open Access Journals (Sweden)

Christopher Fellows

2016-12-01

Full Text Available Current cell-based repair strategies have proven unsuccessful for treating cartilage defects and osteoarthritic lesions, consequently advances in innovative therapeutics are required and mesenchymal stem cell-based (MSC therapies are an expanding area of investigation. MSCs are capable of differentiating into multiple cell lineages and exerting paracrine effects. Due to their easy isolation, expansion and low immunogenicity, MSCs are an attractive option for regenerative medicine for joint repair. Recent studies have identified several MSC tissue reservoirs including in adipose tissue, bone marrow, cartilage, periosteum and muscle. MSCs isolated from these discrete tissue niches exhibit distinct biological activities, and have enhanced regenerative potentials for different tissue types. Each MSC type has advantages and disadvantages for cartilage repair and their use in a clinical setting is a balance between expediency and effectiveness. In this review we explore the challenges associated with cartilage repair and regeneration using MSC-based cell therapies and provide an overview of phenotype, biological activities and functional properties for each MSC population. This paper also specifically explores the therapeutic potential of each type of MSC, particularly focusing on which cells are capable of producing stratified hyaline-like articular cartilage regeneration. Finally we highlight areas for future investigation. Given that patients present with a variety of problems it is unlikely that cartilage regeneration will be a simple ‘one size fits all’, but more likely an array of solutions that need to applied systematically to achieve regeneration of a biomechanically competent repair tissue.

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

International Nuclear Information System (INIS)

Araujo, A.C. de.

1980-01-01

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)

Transactivation domain of p53 regulates DNA repair and integrity in human iPS cells.

Science.gov (United States)

Kannappan, Ramaswamy; Mattapally, Saidulu; Wagle, Pooja A; Zhang, Jianyi

2018-05-18

The role of p53 transactivation domain (p53-TAD), a multifunctional and dynamic domain, on DNA repair and retaining DNA integrity in human iPS cells has never been studied. p53-TAD was knocked out in iPS cells using CRISPR/Cas9 and was confirmed by DNA sequencing. p53-TAD KO cells were characterized by: accelerated proliferation, decreased population doubling time, and unaltered Bcl2, BBC3, IGF1R, Bax and altered Mdm2, p21, and PIDD transcripts expression. In p53-TAD KO cells p53 regulated DNA repair proteins XPA, DNA polH and DDB2 expression were found to be reduced compared to p53-WT cells. Exposure to low dose of doxorubicin (Doxo) induced similar DNA damage and DNA damage response (DDR) measured by RAD50 and MRE11 expression, Checkpoint kinase 2 activation and γH2A.X recruitment at DNA strand breaks in both the cell groups indicating silencing p53-TAD do not affect DDR mechanism upstream of p53. Following removal of Doxo p53-WT hiPS cells underwent DNA repair, corrected their damaged DNA and restored DNA integrity. Conversely, p53-TAD KO hiPS cells did not undergo complete DNA repair and failed to restore DNA integrity. More importantly continuous culture of p53-TAD KO hiPS cells underwent G2/M cell cycle arrest and expressed cellular senescent marker p16 INK4a . Our data clearly shows that silencing transactivation domain of p53 did not affect DDR but affected the DNA repair process implying the crucial role of p53 transactivation domain in maintaining DNA integrity. Therefore, activating p53-TAD domain using small molecules may promote DNA repair and integrity of cells and prevent senescence.

Repair of potentially lethal damage in unfed plateau phase cultures of Ehrlich ascited tumour cells

International Nuclear Information System (INIS)

Illiakis, G.

1980-01-01

Plateau phase EAT-cells have been irradiated at different times in the plateau phase and their ability to repair PLD has been measured. A large capacity to repair PLD has been observed if the cultures were kept in the plateau phase for some hours after irradiation before diluting and plating to measure the survival. In combination with theoretical considerations it is concluded that almost all the PLD produced under these conditions can be repaired. The reaction rate of this repair was independent of the dose and the age of the culture. The results also indicate that PLD repair is independent of the intercellular contact of EAT-cells. (author)

Decreased UV-induced DNA repair synthesis in peripheral leukocytes from patients with the nevoid basal cell carcinoma syndrome

International Nuclear Information System (INIS)

Ringborg, U.; Lambert, B.; Landergen, J.; Lewensohn, R.

1981-01-01

The uv-induced DNA repair synthesis in peripheral leukocytes from 7 patients with the nevoid basal cell carcinoma syndrome was compared to that in peripheral leukocytes from 5 patients with basal cell carcinomas and 39 healthy subjects. A dose response curve was established for each individual, and maximum DNA repair synthesis was used as a measure of the capacity for DNA repair. The patients with the nevoid basal cell carcinoma syndrome had about 25% lower level of maximum DNA repair synthesis as compared to the patients with basal cell carcinomas and control individuals. The possibility that DNA repair mechanisms may be involved in the etiology to the nevoid basal cell carcinoma syndrome is discussed

Repair of γ-irradiation-induced DNA single-strand breaks in human bone marrow cells. Analysis of unfractionated and CD34+ cells using single-cell gel electrophoresis

International Nuclear Information System (INIS)

Lankinen, Maarit H.; Vilpo, Juhani A.

1997-01-01

Human bone marrow mononuclear cells (BMMNCs) were separated by density gradient centrifugation, and a subpopulation of progenitor cells was further isolated using anti-CD34-coated magnetic beads. The cells were irradiated with γ-rays (0.93-5.43 Gy) from a 137 Cs source. The extent of DNA damage, i.e., single-strand breaks (SSBs) and alkali-labile lesions of individual cells, was investigated using the alkaline single-cell gel electrophoresis technique. The irradiation resulted in a dose-dependent increase in DNA migration, reflecting the number of detectable DNA lesions. An approximately similar extent of SSB formation was observed in BMMNCs and CD34+ cells. Damage was repaired when the cells were incubated at 37C: a fast initial repair phase was followed by a slower rejoining of SSBs in both BMMNC and CD34+ cell populations. A significantly longer time was required to repair the lesions caused by 5.43 Gy than those caused by 0.93 Gy. In the present work we report, for the first time, the induction and repair of DNA SSBs at the level of single human bone marrow cells when exposed to ionizing radiation at clinically relevant doses. These data, together with our previous results with human blood granulocytes and lymphocytes, indicate an approximately similar extent of formation and repair of γ-irradiation-induced DNA SSBs in immature and mature human hematopoietic cells

Multipotent embryonic isl1+ progenitor cells lead to cardiac, smooth muscle, and endothelial cell diversification.

Science.gov (United States)

Moretti, Alessandra; Caron, Leslie; Nakano, Atsushi; Lam, Jason T; Bernshausen, Alexandra; Chen, Yinhong; Qyang, Yibing; Bu, Lei; Sasaki, Mika; Martin-Puig, Silvia; Sun, Yunfu; Evans, Sylvia M; Laugwitz, Karl-Ludwig; Chien, Kenneth R

2006-12-15

Cardiogenesis requires the generation of endothelial, cardiac, and smooth muscle cells, thought to arise from distinct embryonic precursors. We use genetic fate-mapping studies to document that isl1(+) precursors from the second heart field can generate each of these diverse cardiovascular cell types in vivo. Utilizing embryonic stem (ES) cells, we clonally amplified a cellular hierarchy of isl1(+) cardiovascular progenitors, which resemble the developmental precursors in the embryonic heart. The transcriptional signature of isl1(+)/Nkx2.5(+)/flk1(+) defines a multipotent cardiovascular progenitor, which can give rise to cells of all three lineages. These studies document a developmental paradigm for cardiogenesis, where muscle and endothelial lineage diversification arises from a single cell-level decision of a multipotent isl1(+) cardiovascular progenitor cell (MICP). The discovery of ES cell-derived MICPs suggests a strategy for cardiovascular tissue regeneration via their isolation, renewal, and directed differentiation into specific mature cardiac, pacemaker, smooth muscle, and endothelial cell types.

Effect of polyamine depletion on DNA damage and repair following UV irradiation of HeLa cells

International Nuclear Information System (INIS)

Snyder, R.D.; Sunkara, P.S.

1990-01-01

Treatment of HeLa cells with the polyamine biosynthesis inhibitors, methylglyoxal bis(guanylhydrazone) (MGBG), difluoromethylornithine (DFMO) or a combination of the two, resulted in reduction in cellular polyamine levels. Analysis of UV light-induced DNA damage and repair in these polyamine depleted cells revealed distinct differences in the repair process relative to that seen in cells possessing a normal polyamine complement. Observed patterns of differential polyamine depletion by DFMO and MGBG, and partial reversal of repair inhibition by polyamine supplementation, suggest that polyamine depletion per se, rather than some secondary effect of inhibitor treatment, is responsible for the inhibition of repair. (author)

Effect of polyamine depletion on DNA damage and repair following UV irradiation of HeLa cells

Energy Technology Data Exchange (ETDEWEB)

Snyder, R.D.; Sunkara, P.S. (Merrell Dow Research Inst., Cincinnati, OH (USA))

1990-09-01

Treatment of HeLa cells with the polyamine biosynthesis inhibitors, methylglyoxal bis(guanylhydrazone) (MGBG), difluoromethylornithine (DFMO) or a combination of the two, resulted in reduction in cellular polyamine levels. Analysis of UV light-induced DNA damage and repair in these polyamine depleted cells revealed distinct differences in the repair process relative to that seen in cells possessing a normal polyamine complement. Observed patterns of differential polyamine depletion by DFMO and MGBG, and partial reversal of repair inhibition by polyamine supplementation, suggest that polyamine depletion per se, rather than some secondary effect of inhibitor treatment, is responsible for the inhibition of repair. (author).

Stem cells for brain repair in neonatal hypoxia-ischemia.

Science.gov (United States)

Chicha, L; Smith, T; Guzman, R

2014-01-01

Neonatal hypoxic-ischemic insults are a significant cause of pediatric encephalopathy, developmental delays, and spastic cerebral palsy. Although the developing brain's plasticity allows for remarkable self-repair, severe disruption of normal myelination and cortical development upon neonatal brain injury are likely to generate life-persisting sensory-motor and cognitive deficits in the growing child. Currently, no treatments are available that can address the long-term consequences. Thus, regenerative medicine appears as a promising avenue to help restore normal developmental processes in affected infants. Stem cell therapy has proven effective in promoting functional recovery in animal models of neonatal hypoxic-ischemic injury and therefore represents a hopeful therapy for this unmet medical condition. Neural stem cells derived from pluripotent stem cells or fetal tissues as well as umbilical cord blood and mesenchymal stem cells have all shown initial success in improving functional outcomes. However, much still remains to be understood about how those stem cells can safely be administered to infants and what their repair mechanisms in the brain are. In this review, we discuss updated research into pathophysiological mechanisms of neonatal brain injury, the types of stem cell therapies currently being tested in this context, and the potential mechanisms through which exogenous stem cells might interact with and influence the developing brain.

DNA replication and repair of Tilapia cells: Pt. 2

International Nuclear Information System (INIS)

Chen, J.D.; Yew, F.H.

1988-01-01

TO-2 is a fish cell line derived from the Tilapia ovary. It grows over a wide range of temperature (15-34 0 C). We report the effects of temperature on DNA replication and u.v. repair in TO-2 cells. When the cells were moved from 31 0 C to the sublethal high temperature of 37 0 C, the rate of DNA synthesis first decreased to 60%, then speedy recovery soon set in, and after 8h at 37 0 C the rate of DNA synthesis overshot the 31 0 C control level by 180%. When moved to low temperature (18 0 C) Tilapia cells also showed an initial suppression of DNA synthesis before settling at 30% of the control level. U.V. reduced but could not block DNA synthesis completely. The inhibition was overcome in 3h at 37, 31 and 25 0 C, but not at 18 0 C. Initiation of nascent DNA synthesis was blocked at 4Jm -2 in TO-2 cells compared with ≤ 1Jm -2 in mammalian cells. After 9Jm -2 u.v. irradiation, low molecular weight DNA replication intermediates started to accumulate. TO-2 cells showed low levels of u.v.-induced excision repair. (author)

Effects of cytotoxic chemotherapeutic agents on split-dose repair in intestinal crypt cells

International Nuclear Information System (INIS)

Phillips, Theodore L.; Ross, Glenda Y.

1997-01-01

Purpose: Many cancer chemotherapeutic agents interact with radiation to enhance the amount of radiation damage observed in both tumor and normal tissues. It is important to predict this interaction and to determine the effect of drug on sublethal damage repair. To evaluate for effects in rapid renewing normal tissues, the intestinal crypt cell in vivo assay is an excellent one to employ. These studies investigate the effect of eleven cancer chemotherapeutic drugs on split-dose repair in the intestinal crypt cell of the mouse. Methods and Materials: LAF1 male mice, age 10-12 weeks, were exposed to whole-body irradiation with orthovoltage x-rays delivered as a single dose or as equally divided doses delivered with intervals between the two exposures of 2 to 24 h. In the experimental group, the cancer chemotherapeutic agent was administered intraperitoneally 2 h before the first radiation dose. At 3.6 days after the second irradiation, the mice were sacrificed; the jejunum was removed, fixed, and sectioned for light microscopy. The number of regenerating crypts were counted and corrected to represent the number of surviving cells per circumference. Results: Of the eleven drugs tested, only carmustine eliminated split-dose repair. Cisplatin delayed repair, and methotrexate caused marked synchronization obliterating the observation of split-dose repair. Conclusions: Most cytotoxic chemotherapeutic agents do not inhibit sublethal damage repair in intestinal crypt cells when given 2 h before the first radiation exposure. Absence of the initial increase in survival seen with split-dose radiation is noted with carmustine and high-dose methotrexate

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

Bayesian Sensitivity Analysis of a Cardiac Cell Model Using a Gaussian Process Emulator

Science.gov (United States)

Chang, Eugene T Y; Strong, Mark; Clayton, Richard H

2015-01-01

Models of electrical activity in cardiac cells have become important research tools as they can provide a quantitative description of detailed and integrative physiology. However, cardiac cell models have many parameters, and how uncertainties in these parameters affect the model output is difficult to assess without undertaking large numbers of model runs. In this study we show that a surrogate statistical model of a cardiac cell model (the Luo-Rudy 1991 model) can be built using Gaussian process (GP) emulators. Using this approach we examined how eight outputs describing the action potential shape and action potential duration restitution depend on six inputs, which we selected to be the maximum conductances in the Luo-Rudy 1991 model. We found that the GP emulators could be fitted to a small number of model runs, and behaved as would be expected based on the underlying physiology that the model represents. We have shown that an emulator approach is a powerful tool for uncertainty and sensitivity analysis in cardiac cell models. PMID:26114610

Fluorescent Reporters in Human Pluripotent Stem Cells: Contributions to Cardiac Differentiation and Their Applications in Cardiac Disease and Toxicity

NARCIS (Netherlands)

den Hartogh, Sabine C.; Passier, Petrus Christianus Johannes Josephus

2016-01-01

In the last decade, since the first report of induced pluripotent stem cells, the stem cell field has made remarkable progress in the differentiation to specialized cell-types of various tissues and organs, including the heart. Cardiac lineage- and tissue-specific human pluripotent stem cell (hPSC)

Un-repairable DNA damage in cell due to irradiation

International Nuclear Information System (INIS)

Yoshii, Giichi

1992-01-01

Radiation-induced cell reproductive deactivation is caused by damage to DNA. In a cell, cellular DNA radical reacts with diffusion controlled rate and generates DNA peroxide radical. The chemical repair of DNA radical with hydrogen donation by thiol competes with the reaction of oxygen with same radicals in the DNA molecules. From the point reaction rates, the prolongation of radical life time is not as great as expected from the reduction in the glutathione content of the cell. This indicates that further reducting compounds (protein bound thiol) are present in the cell. The residual radicals are altered to strand breaks, base damages and so on. The effective lesions for a number of endpoints is un-repaired double strand break, which has been discovered in a cluster. This event gives risk to high LET radiation or to a track end of X-rays. For X- or electron irradiations the strand breaks are frequently induced by the interactions between sublesions on two strands in DNA. A single strand break followed by radical action may be unstable excited state, because of remaining sugar radical action and of having negative charged phosphates, in which strands breaks will be rejoined in a short time to stable state. On the same time, a break in the double helix will be immediately produced if two breaks are on either or approximately opposite locations. The formation of a double strand break in the helix depends on the ion strength of the cell. The potassium ions are largely released from polyanionic strand during irradiation, which results in the induction of denatured region. Double strand break with the denatured region seems to be un-repairable DNA damage. (author)

Three-Dimensional Printing and Cell Therapy for Wound Repair.

Science.gov (United States)

van Kogelenberg, Sylvia; Yue, Zhilian; Dinoro, Jeremy N; Baker, Christopher S; Wallace, Gordon G

2018-05-01

Significance: Skin tissue damage is a major challenge and a burden on healthcare systems, from burns and other trauma to diabetes and vascular disease. Although the biological complexities are relatively well understood, appropriate repair mechanisms are scarce. Three-dimensional bioprinting is a layer-based approach to regenerative medicine, whereby cells and cell-based materials can be dispensed in fine spatial arrangements to mimic native tissue. Recent Advances: Various bioprinting techniques have been employed in wound repair-based skin tissue engineering, from laser-induced forward transfer to extrusion-based methods, and with the investigation of the benefits and shortcomings of each, with emphasis on biological compatibility and cell proliferation, migration, and vitality. Critical issues: Development of appropriate biological inks and the vascularization of newly developed tissues remain a challenge within the field of skin tissue engineering. Future Directions: Progress within bioprinting requires close interactions between material scientists, tissue engineers, and clinicians. Microvascularization, integration of multiple cell types, and skin appendages will be essential for creation of complex skin tissue constructs.

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.

Stem Cells for Cartilage Repair: Preclinical Studies and Insights in Translational Animal Models and Outcome Measures

Directory of Open Access Journals (Sweden)

Melissa Lo Monaco

2018-01-01

Full Text Available Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs or induced pluripotent stem cells (iPSCs have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles. But before novel cell-based therapies for cartilage repair can be introduced into the clinic, rigorous testing in preclinical animal models is required. Preclinical models used in regenerative cartilage studies include murine, lapine, caprine, ovine, porcine, canine, and equine models, each associated with its specific advantages and limitations. This review presents a summary of recent in vitro data and from in vivo preclinical studies justifying the use of MSCs and iPSCs in cartilage tissue engineering. Moreover, the advantages and disadvantages of utilizing small and large animals will be discussed, while also describing suitable outcome measures for evaluating cartilage repair.

Stem Cells for Cartilage Repair: Preclinical Studies and Insights in Translational Animal Models and Outcome Measures.

Science.gov (United States)

Lo Monaco, Melissa; Merckx, Greet; Ratajczak, Jessica; Gervois, Pascal; Hilkens, Petra; Clegg, Peter; Bronckaers, Annelies; Vandeweerd, Jean-Michel; Lambrichts, Ivo

2018-01-01

Due to the restricted intrinsic capacity of resident chondrocytes to regenerate the lost cartilage postinjury, stem cell-based therapies have been proposed as a novel therapeutic approach for cartilage repair. Moreover, stem cell-based therapies using mesenchymal stem cells (MSCs) or induced pluripotent stem cells (iPSCs) have been used successfully in preclinical and clinical settings. Despite these promising reports, the exact mechanisms underlying stem cell-mediated cartilage repair remain uncertain. Stem cells can contribute to cartilage repair via chondrogenic differentiation, via immunomodulation, or by the production of paracrine factors and extracellular vesicles. But before novel cell-based therapies for cartilage repair can be introduced into the clinic, rigorous testing in preclinical animal models is required. Preclinical models used in regenerative cartilage studies include murine, lapine, caprine, ovine, porcine, canine, and equine models, each associated with its specific advantages and limitations. This review presents a summary of recent in vitro data and from in vivo preclinical studies justifying the use of MSCs and iPSCs in cartilage tissue engineering. Moreover, the advantages and disadvantages of utilizing small and large animals will be discussed, while also describing suitable outcome measures for evaluating cartilage repair.

Cardiac Progenitor Cell Extraction from Human Auricles

KAUST Repository

Di Nardo, Paolo

2017-02-22

For many years, myocardial tissue has been considered terminally differentiated and, thus, incapable of regenerating. Recent studies have shown, instead, that cardiomyocytes, at least in part, are slowly substituted by new cells originating by precursor cells mostly embedded into the heart apex and in the atria. We have shown that an elective region of progenitor cell embedding is represented by the auricles, non-contractile atria appendages that can be easily sampled without harming the patient. The protocol here reported describes how from auricles a population of multipotent, cardiogenic cells can be isolated, cultured, and differentiated. Further studies are needed to fully exploit this cell population, but, sampling auricles, it could be possible to treat cardiac patients using their own cells circumventing rejection or organ shortage limitations.

A preliminary investigation into the extent of increased radioresistance or hyper-radiosensitivity in cells of hamster cell lines known to be deficient in DNA repair

International Nuclear Information System (INIS)

Skov, K.; Marples, B.; Matthews, J.B.; Zhou, H.; Joiner, M.C.

1994-01-01

The response to low doses of X rays was assessed in cells of three hamster cell lines which are defective in DNA repair and was compared with their parental lines. Cells of the V79-derived double-strand break repair-deficient line XR-V15B showed no radioresistance in the 0.5-Gy range compared with the V79B wild type, but instead showed an exponential response. Cells of the single-strand break repair-deficient line EM9 showed hyper-radiosensitivity and exhibited increased radioresistance. Most interestingly, cells of the UV-20 cell line appeared to respond exponentially, as a continuation of the hyper-radiosensitive portion of the curve, with no evidence of increased radioresistance. This line is defective in an incision step of excision repair and is sensitive to crosslinking agents. Further studies are warranted to address the possible role of single- and double-strand break repair and excision repair in hyper-radiosensitivity and increased radioresistance. 24 refs., 4 figs

Embryological origin of the endocardium and derived valve progenitor cells: from developmental biology to stem cell-based valve repair.

Science.gov (United States)

Pucéat, Michel

2013-04-01

The cardiac valves are targets of both congenital and acquired diseases. The formation of valves during embryogenesis (i.e., valvulogenesis) originates from endocardial cells lining the myocardium. These cells undergo an endothelial-mesenchymal transition, proliferate and migrate within an extracellular matrix. This leads to the formation of bilateral cardiac cushions in both the atrioventricular canal and the outflow tract. The embryonic origin of both the endocardium and prospective valve cells is still elusive. Endocardial and myocardial lineages are segregated early during embryogenesis and such a cell fate decision can be recapitulated in vitro by embryonic stem cells (ESC). Besides genetically modified mice and ex vivo heart explants, ESCs provide a cellular model to study the early steps of valve development and might constitute a human therapeutic cell source for decellularized tissue-engineered valves. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction. Copyright © 2012 Elsevier B.V. All rights reserved.

DNA replication and repair of Tilapia cells: Pt. 2. Effects of temperature on DNA replication and ultraviolet repair in Tilapia ovary cells

Energy Technology Data Exchange (ETDEWEB)

Chen, J.D.; Yew, F.H.

1988-02-01

TO-2 is a fish cell line derived from the Tilapia ovary. It grows over a wide range of temperature (15-34/sup 0/C). We report the effects of temperature on DNA replication and u.v. repair in TO-2 cells. When the cells were moved from 31/sup 0/C to the sublethal high temperature of 37/sup 0/C, the rate of DNA synthesis first decreased to 60%, then speedy recovery soon set in, and after 8h at 37/sup 0/C the rate of DNA synthesis overshot the 31/sup 0/C control level by 180%. When moved to low temperature (18/sup 0/C) Tilapia cells also showed an initial suppression of DNA synthesis before settling at 30% of the control level. U.V. reduced but could not block DNA synthesis completely. The inhibition was overcome in 3h at 37, 31 and 25/sup 0/C, but not at 18/sup 0/C. Initiation of nascent DNA synthesis was blocked at 4Jm/sup -2/ in TO-2 cells compared with less than or equal to 1Jm/sup -2/ in mammalian cells. After 9Jm/sup -2/ u.v. irradiation, low molecular weight DNA replication intermediates started to accumulate. TO-2 cells showed low levels of u.v.-induced excision repair.

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.

Repair and cell cycle response in cells exposed to environmental biohazards. Progress report, October 1, 1976--May 31, 1979

International Nuclear Information System (INIS)

Billen, D.

1979-01-01

A wide variety of environmental agents are known which induce damage in DNA leading to an inhibition of DNA synthesis or faulty replication. Both results may cause cell death or mutation. Both bacteria and mommalian cells are being used to assess the roles of the several known DNA polymerases and other DNA metabolic enzymes and factors in DNA repair, replication and recombination. The many DNA mutants of E. coli and B. subtilis provide a genetic approach to measuring the role of individual components of the DNA repair and replicative system. Because of the advantage of controlling pools and precursors of nucleic acid synthesis we have further developed the use of permeabilized cells for such studies. In addition a series of repair studies with Bacillus subtilis have been carried on because of the unique genetic manipulation of this system which includes the ability of cells to be easily transformed by exogenous DNA. The information obtained with prokaryotes provides leads to assess the details of DNA repair and replication in mammalian systems including man

Stem cell secretome-rich nanoclay hydrogel: a dual action therapy for cardiovascular regeneration

Science.gov (United States)

Waters, Renae; Pacelli, Settimio; Maloney, Ryan; Medhi, Indrani; Ahmed, Rafeeq P. H.; Paul, Arghya

2016-03-01

A nanocomposite hydrogel with photocrosslinkable micro-porous networks and a nanoclay component was successfully prepared to control the release of growth factor-rich stem cell secretome. The proven pro-angiogenic and cardioprotective potential of this new bioactive system provides a valuable therapeutic platform for cardiac tissue repair and regeneration.A nanocomposite hydrogel with photocrosslinkable micro-porous networks and a nanoclay component was successfully prepared to control the release of growth factor-rich stem cell secretome. The proven pro-angiogenic and cardioprotective potential of this new bioactive system provides a valuable therapeutic platform for cardiac tissue repair and regeneration. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr07806g

Cardiac stem/progenitor cells, secreted proteins, and proteomics

Czech Academy of Sciences Publication Activity Database

Šťastná, Miroslava; Abraham, M.R.; Van Eyk, J.E.

2009-01-01

Roč. 583, č. 11 (2009), s. 1800-1807 ISSN 0014-5793 Institutional research plan: CEZ:AV0Z40310501 Keywords : Cardiac stem/progenitor cell * paracrine factor * secretome Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.541, year: 2009

Translational Application of Microfluidics and Bioprinting for Stem Cell-Based Cartilage Repair

Directory of Open Access Journals (Sweden)

Silvia Lopa

2018-01-01

Full Text Available Cartilage defects can impair the most elementary daily activities and, if not properly treated, can lead to the complete loss of articular function. The limitations of standard treatments for cartilage repair have triggered the development of stem cell-based therapies. In this scenario, the development of efficient cell differentiation protocols and the design of proper biomaterial-based supports to deliver cells to the injury site need to be addressed through basic and applied research to fully exploit the potential of stem cells. Here, we discuss the use of microfluidics and bioprinting approaches for the translation of stem cell-based therapy for cartilage repair in clinics. In particular, we will focus on the optimization of hydrogel-based materials to mimic the articular cartilage triggered by their use as bioinks in 3D bioprinting applications, on the screening of biochemical and biophysical factors through microfluidic devices to enhance stem cell chondrogenesis, and on the use of microfluidic technology to generate implantable constructs with a complex geometry. Finally, we will describe some new bioprinting applications that pave the way to the clinical use of stem cell-based therapies, such as scaffold-free bioprinting and the development of a 3D handheld device for the in situ repair of cartilage defects.

Translational Application of Microfluidics and Bioprinting for Stem Cell-Based Cartilage Repair

Science.gov (United States)

Mondadori, Carlotta; Mainardi, Valerio Luca; Talò, Giuseppe; Candrian, Christian; Święszkowski, Wojciech

2018-01-01

Cartilage defects can impair the most elementary daily activities and, if not properly treated, can lead to the complete loss of articular function. The limitations of standard treatments for cartilage repair have triggered the development of stem cell-based therapies. In this scenario, the development of efficient cell differentiation protocols and the design of proper biomaterial-based supports to deliver cells to the injury site need to be addressed through basic and applied research to fully exploit the potential of stem cells. Here, we discuss the use of microfluidics and bioprinting approaches for the translation of stem cell-based therapy for cartilage repair in clinics. In particular, we will focus on the optimization of hydrogel-based materials to mimic the articular cartilage triggered by their use as bioinks in 3D bioprinting applications, on the screening of biochemical and biophysical factors through microfluidic devices to enhance stem cell chondrogenesis, and on the use of microfluidic technology to generate implantable constructs with a complex geometry. Finally, we will describe some new bioprinting applications that pave the way to the clinical use of stem cell-based therapies, such as scaffold-free bioprinting and the development of a 3D handheld device for the in situ repair of cartilage defects. PMID:29535776

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.

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.

Repair and cell cycle response in cells exposed to environmental biohazards. Progress report, February 1, 1976--May 31, 1977

International Nuclear Information System (INIS)

Billen, D.

1977-01-01

Progress is reported on the following research projects: DNA polymerase III dependent repair of x-ray damage in Escherichia coli; regulation of reinsertation of nucleotides by DNA ligase; DNA synthesis in permeabilized CHO cells; measurement of damage to DNA in Bacillus subtilis; repair defect in rec A cells; inactivation of transforming DNA; and mutagenesis of transforming DNA

Opening of the inward rectifier potassium channel alleviates maladaptive tissue repair following myocardial infarction.

Science.gov (United States)

Liu, Chengfang; Liu, Enli; Luo, Tiane; Zhang, Weifang; He, Rongli

2016-08-01

Activation of the inward rectifier potassium current (IK1) channel has been reported to be associated with suppression of ventricular arrhythmias. In this study, we tested the hypothesis that opening of the IK1 channel with zacopride (ZAC) was involved in the modulation of tissue repair after myocardial infarction. Sprague-Dawley rats were subject to coronary artery ligation and ZAC was administered intraperitoneally (15 µg/kg/day) for 28 days. Compared with the ischemia group, treatment with ZAC significantly reduced the ratio of heart/body weight and the cross-sectional area of cardiomyocytes, suggesting less cardiac hypertrophy. ZAC reduced the accumulation of collagen types I and III, accompanied with decrease of collagen area, which were associated with a reduction of collagen deposition in the fibrotic myocardium. Echocardiography showed improved cardiac function, evidenced by the reduced left ventricular end-diastolic dimension and left ventricular end-systolic dimension, and the increased ejection fraction and fractional shortening in ZAC-treated animals (all P < 0.05 vs. ischemia group). In coincidence with these changes, ZAC up-regulated the protein level of the IK1 channel and down-regulated the phosphorylation of mammalian target of rapamycin (mTOR) and 70-kDa ribosomal protein S6 (p70S6) kinase. Administration of chloroquine alone, an IK1 channel antagonist, had no effect on all the parameters measured, but significantly blocked the beneficial effects of ZAC on cardiac repair. In conclusion, opening of the IK1 channel with ZAC inhibits maladaptive tissue repair and improves cardiac function, potentially mediated by the inhibition of ischemia-activated mTOR-p70S6 signaling pathway via the IK1 channel. So the development of pharmacological agents specifically targeting the activation of the IK1 channel may protect the heart against myocardial ischemia-induced cardiac dysfunction. © The Author 2016. Published by Oxford University Press on behalf of

Osteocalcin expressing cells from tendon sheaths in mice contribute to tendon repair by activating Hedgehog signaling

OpenAIRE

Wang, Yi; Zhang, Xu; Huang, Huihui; Xia, Yin; Yao, YiFei; Mak, Arthur Fuk-Tat; Yung, Patrick Shu-Hang; Chan, Kai-Ming; Wang, Li; Zhang, Chenglin; Huang, Yu; Mak, Kingston King-Lun

2017-01-01

Both extrinsic and intrinsic tissues contribute to tendon repair, but the origin and molecular functions of extrinsic tissues in tendon repair are not fully understood. Here we show that tendon sheath cells harbor stem/progenitor cell properties and contribute to tendon repair by activating Hedgehog signaling. We found that Osteocalcin (Bglap) can be used as an adult tendon-sheath-specific marker in mice. Lineage tracing experiments show that Bglap-expressing cells in adult sheath tissues pos...

Optimal Population of Embryonic Stem Cells in "Hanging Drop" Culture for in-vitro Differentiation to Cardiac Myocytes

OpenAIRE

MIWA, Keiko; LEE, Jong-Kook; HIDAKA, Kyoko; SHI, Rong-qian; MORISAKI, Takayuki; KODAMA, Itsuo

2002-01-01

Pluripotent embryonic stem (ES) cells differentiate to cardiac myocytes in vitro by many other previous reports demonstrated "hanging-drop" method. In this study, the number of ES cells in each hanging-drop plays an important role in the cultivation of cardiac myocytes. We examined the optimal hanging-drop size to obtain embryonic stem cell-derived cardiac cells (ESCMs) in vitro using specific labeled mouse ES cells (hCGP7) which were stably transfected with the enhanced green fluorescent pro...

Genetic modification of embryonic stem cells with VEGF enhances cell survival and improves cardiac function.

Science.gov (United States)

Xie, Xiaoyan; Cao, Feng; Sheikh, Ahmad Y; Li, Zongjin; Connolly, Andrew J; Pei, Xuetao; Li, Ren-Ke; Robbins, Robert C; Wu, Joseph C

2007-01-01

Cardiac stem cell therapy remains hampered by acute donor cell death posttransplantation and the lack of reliable methods for tracking cell survival in vivo. We hypothesize that cells transfected with inducible vascular endothelial growth factor 165 (VEGF(165)) can improve their survival as monitored by novel molecular imaging techniques. Mouse embryonic stem (ES) cells were transfected with an inducible, bidirectional tetracycline (Bi-Tet) promoter driving VEGF(165) and renilla luciferase (Rluc). Addition of doxycycline induced Bi-Tet expression of VEGF(165) and Rluc significantly compared to baseline (p<0.05). Expression of VEGF(165) enhanced ES cell proliferation and inhibited apoptosis as determined by Annexin-V staining. For noninvasive imaging, ES cells were transduced with a double fusion (DF) reporter gene consisting of firefly luciferase and enhanced green fluorescence protein (Fluc-eGFP). There was a robust correlation between cell number and Fluc activity (R(2)=0.99). Analysis by immunostaining, histology, and RT-PCR confirmed that expression of Bi-Tet and DF systems did not affect ES cell self-renewal or pluripotency. ES cells were differentiated into beating embryoid bodies expressing cardiac markers such as troponin, Nkx2.5, and beta-MHC. Afterward, 5 x 10(5) cells obtained from these beating embryoid bodies or saline were injected into the myocardium of SV129 mice (n=36) following ligation of the left anterior descending (LAD) artery. Bioluminescence imaging (BLI) and echocardiography showed that VEGF(165) induction led to significant improvements in both transplanted cell survival and cardiac function (p<0.05). This is the first study to demonstrate imaging of embryonic stem cell-mediated gene therapy targeting cardiovascular disease. With further validation, this platform may have broad applications for current basic research and further clinical studies.

Application of rapid artificial cardiac pacing in thoracic endovascular aortic repair in aged patients

Directory of Open Access Journals (Sweden)

Chen J

2013-12-01

Full Text Available Jun Chen,1,* Wenhui Huang,2,* Songyuan Luo,2,* Dahao Yang,1 Zhengrong Xu,1 Jianfang Luo21Department of Angiocardiopathy, Affiliated Baoan Hospital of Southern Medical University, Shenzhen City, People's Republic of China; 2Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, People's Republic of China*These authors contributed equally to this workObjective: To compare the safety, efficacy, and impact on stent graft positioning between rapid artificial cardiac pacing (RACP, induced hypotension and sodium nitroprusside (SNP induced hypotension during thoracic endovascular aortic repair (TEVAR for Stanford B aortic dissection.Methods: One hundred and sixty-eight patients, who were diagnosed with Stanford B aortic dissection and who underwent selective TEVAR in Guangdong General Hospital and the People's Hospital of Baoan District, Shenzhen, People's Republic of China, were enrolled in this study. Patients were randomly divided into a RACP group (n=77 and a SNP group (n=91. During localization and deployment of the stent graft, hypotension was induced by RACP or intravenous SNP, according to randomization. Hemodynamics, landing precision (deviation from planned placement site, duration of procedure, renal function, neurocognitive function, and incidence of endoleaks and paraplegia/hemiplegia were compared. Except for methods of inducing hypotension, TEVAR was performed according to the same protocol in each group.Results: RACP was successfully performed in all patients assigned to the RACP group. Compared with the SNP group, blood pressure was significantly lower (43±5 versus 81±6 mmHg, P=0.003 and the restoration time of blood pressure and the operation duration were significantly shorter (7±2 versus 451±87 seconds, P<0.001; 87±15 versus 106±18 minutes, P<0.001, respectively in the RACP group. Stent graft localization/deployment was more precise in the RACP

Altering Cell Survival by Modulating Levels of Mitochondrial DNA Repair Enzymes

National Research Council Canada - National Science Library

Shokolenko, Inna

2002-01-01

.... Our previous results demonstrated that stable expression of E.coli Exonuclease III in mitochondria of breast cancer cells diminishes mtDNA repair capacity following oxidative stress, which leads to a decrease in long-term cell survival...

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.

Rhodium metalloinsertor binding generates a lesion with selective cytotoxicity for mismatch repair-deficient cells.

Science.gov (United States)

Bailis, Julie M; Weidmann, Alyson G; Mariano, Natalie F; Barton, Jacqueline K

2017-07-03

The DNA mismatch repair (MMR) pathway recognizes and repairs errors in base pairing and acts to maintain genome stability. Cancers that have lost MMR function are common and comprise an important clinical subtype that is resistant to many standard of care chemotherapeutics such as cisplatin. We have identified a family of rhodium metalloinsertors that bind DNA mismatches with high specificity and are preferentially cytotoxic to MMR-deficient cells. Here, we characterize the cellular mechanism of action of the most potent and selective complex in this family, [Rh(chrysi)(phen)(PPO)] 2+ (Rh-PPO). We find that Rh-PPO binding induces a lesion that triggers the DNA damage response (DDR). DDR activation results in cell-cycle blockade and inhibition of DNA replication and transcription. Significantly, the lesion induced by Rh-PPO is not repaired in MMR-deficient cells, resulting in selective cytotoxicity. The Rh-PPO mechanism is reminiscent of DNA repair enzymes that displace mismatched bases, and is differentiated from other DNA-targeted chemotherapeutics such as cisplatin by its potency, cellular mechanism, and selectivity for MMR-deficient cells.

Combined administration of mesenchymal stem cells overexpressing IGF-1 and HGF enhances neovascularization but moderately improves cardiac regeneration in a porcine model.

Science.gov (United States)

Gómez-Mauricio, Guadalupe; Moscoso, Isabel; Martín-Cancho, María-Fernanda; Crisóstomo, Verónica; Prat-Vidal, Cristina; Báez-Díaz, Claudia; Sánchez-Margallo, Francisco M; Bernad, Antonio

2016-07-16

Insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) are among the most promising growth factors for promoting cardiorepair. Here, we evaluated the combination of cell- and gene-based therapy using mesenchymal stem cells (MSC) genetically modified to overexpress IGF-1 or HGF to treat acute myocardial infarction (AMI) in a porcine model. Pig MSC from adipose tissue (paMSC) were genetically modified for evaluation of different therapeutic strategies to improve AMI treatment. Three groups of infarcted Large White pigs were compared (I, control, non-transplanted; II, transplanted with paMSC-GFP (green fluorescent protein); III, transplanted with paMSC-IGF-1/HGF). Cardiac function was evaluated non-invasively using magnetic resonance imaging (MRI) for 1 month. After euthanasia and sampling of the animal, infarcted areas were studied by histology and immunohistochemistry. Intramyocardial transplant in a porcine infarct model demonstrated the safety of paMSC in short-term treatments. Treatment with paMSC-IGF-1/HGF (1:1) compared with the other groups showed a clear reduction in inflammation in some sections analyzed and promoted angiogenic processes in ischemic tissue. Although cardiac function parameters were not significantly improved, cell retention and IGF-1 overexpression was confirmed within the myocardium. The simultaneous administration of IGF-1- and HGF-overexpressing paMSC appears not to promote a synergistic effect or effective repair. The combined enhancement of neovascularization and fibrosis in paMSC-IGF-1/HGF-treated animals nonetheless suggests that sustained exposure to high IGF-1 + HGF levels promotes beneficial as well as deleterious effects that do not improve overall cardiac regeneration.

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

International Nuclear Information System (INIS)

Stark, M.; Naiman, T.; Canaani, D.

1989-01-01

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 [ 3 H]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

Aorto-right atrial fistula after Bentall repair