Imaging-guided two-photon excitation-emission-matrix measurements of human skin tissues

Science.gov (United States)

Yu, Yingqiu; Lee, Anthony M. D.; Wang, Hequn; Tang, Shuo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

2012-07-01

There are increased interests on using multiphoton imaging and spectroscopy for skin tissue characterization and diagnosis. However, most studies have been done with just a few excitation wavelengths. Our objective is to perform a systematic study of the two-photon fluorescence (TPF) properties of skin fluorophores, normal skin, and diseased skin tissues. A nonlinear excitation-emission-matrix (EEM) spectroscopy system with multiphoton imaging guidance was constructed. A tunable femtosecond laser was used to vary excitation wavelengths from 730 to 920 nm for EEM data acquisition. EEM measurements were performed on excised fresh normal skin tissues, seborrheic keratosis tissue samples, and skin fluorophores including: NADH, FAD, keratin, melanin, collagen, and elastin. We found that in the stratum corneum and upper epidermis of normal skin, the cells have large sizes and the TPF originates from keratin. In the lower epidermis, cells are smaller and TPF is dominated by NADH contributions. In the dermis, TPF is dominated by elastin components. The depth resolved EEM measurements also demonstrated that keratin structure has intruded into the middle sublayers of the epidermal part of the seborrheic keratosis lesion. These results suggest that the imaging guided TPF EEM spectroscopy provides useful information for the development of multiphoton clinical devices for skin disease diagnosis.

Human reconstructed skin xenografts on mice to model skin physiology.

Science.gov (United States)

Salgado, Giorgiana; Ng, Yi Zhen; Koh, Li Fang; Goh, Christabelle S M; Common, John E

Xenograft models to study skin physiology have been popular for scientific use since the 1970s, with various developments and improvements to the techniques over the decades. Xenograft models are particularly useful and sought after due to the lack of clinically relevant animal models in predicting drug effectiveness in humans. Such predictions could in turn boost the process of drug discovery, since novel drug compounds have an estimated 8% chance of FDA approval despite years of rigorous preclinical testing and evaluation, albeit mostly in non-human models. In the case of skin research, the mouse persists as the most popular animal model of choice, despite its well-known anatomical differences with human skin. Differences in skin biology are especially evident when trying to dissect more complex skin conditions, such as psoriasis and eczema, where interactions between the immune system, epidermis and the environment likely occur. While the use of animal models are still considered the gold standard for systemic toxicity studies under controlled environments, there are now alternative models that have been approved for certain applications. To overcome the biological limitations of the mouse model, research efforts have also focused on "humanizing" the mice model to better recapitulate human skin physiology. In this review, we outline the different approaches undertaken thus far to study skin biology using human tissue xenografts in mice and the technical challenges involved. We also describe more recent developments to generate humanized multi-tissue compartment mice that carry both a functioning human immune system and skin xenografts. Such composite animal models provide promising opportunities to study drugs, disease and differentiation with greater clinical relevance. Copyright © 2017 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Fabrication and characterization of scaffold from cadaver goat-lung tissue for skin tissue engineering applications.

Science.gov (United States)

Gupta, Sweta K; Dinda, Amit K; Potdar, Pravin D; Mishra, Narayan C

2013-10-01

The present study aims to fabricate scaffold from cadaver goat-lung tissue and evaluate it for skin tissue engineering applications. Decellularized goat-lung scaffold was fabricated by removing cells from cadaver goat-lung tissue enzymatically, to have cell-free 3D-architecture of natural extracellular matrix. DNA quantification assay and Hematoxylin and eosin staining confirmed the absence of cellular material in the decellularized lung-tissue. SEM analysis of decellularized scaffold shows the intrinsic porous structure of lung tissue with well-preserved pore-to-pore interconnectivity. FTIR analysis confirmed non-denaturation and well maintainance of collagenous protein structure of decellularized scaffold. MTT assay, SEM analysis and H&E staining of human skin-derived Mesenchymal Stem cell, seeded over the decellularized scaffold, confirms stem cell attachment, viability, biocompatibility and proliferation over the decellularized scaffold. Expression of Keratin18 gene, along with CD105, CD73 and CD44, by human skin-derived Mesenchymal Stem cells over decellularized scaffold signifies that the cells are viable, proliferating and migrating, and have maintained their critical cellular functions in the presence of scaffold. Thus, overall study proves the applicability of the goat-lung tissue derived decellularized scaffold for skin tissue engineering applications. Copyright © 2013 Elsevier B.V. All rights reserved.

The Effects of Low Dose Irradiation on Inflammatory Response Proteins in a 3D Reconstituted Human Skin Tissue Model

Energy Technology Data Exchange (ETDEWEB)

Varnum, Susan M.; Springer, David L.; Chaffee, Mary E.; Lien, Katie A.; Webb-Robertson, Bobbie-Jo M.; Waters, Katrina M.; Sacksteder, Colette A.

2012-12-01

Skin responses to moderate and high doses of ionizing radiation include the induction of DNA repair, apoptosis, and stress response pathways. Additionally, numerous studies indicate that radiation exposure leads to inflammatory responses in skin cells and tissue. However, the inflammatory response of skin tissue to low dose radiation (<10 cGy) is poorly understood. In order to address this, we have utilized a reconstituted human skin tissue model (MatTek EpiDerm FT) and assessed changes in 23 cytokines twenty-four and forty eight hours following treatment of skin with either 3 or 10 cGy low-dose of radiation. Three cytokines, IFN-γ, IL-2, MIP-1α, were significantly altered in response to low dose radiation. In contrast, seven cytokines were significantly altered in response to a high radiation dose of 200 cGy (IL-2, IL-10, IL-13, IFN-γ, MIP-1α, TNF α, and VEGF) or the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (G-CSF, GM-CSF, IL-1α, IL-8, MIP-1α, MIP-1β, RANTES). Additionally, radiation induced inflammation appears to have a distinct cytokine response relative to the non-radiation induced stressor, TPA. Overall, these results indicate that there are subtle changes in the inflammatory protein levels following exposure to low dose radiation and this response is a sub-set of what is seen following a high dose in a human skin tissue model.

The prediction of blood-tissue partitions, water-skin partitions and skin permeation for agrochemicals.

Science.gov (United States)

Abraham, Michael H; Gola, Joelle M R; Ibrahim, Adam; Acree, William E; Liu, Xiangli

2014-07-01

There is considerable interest in the blood-tissue distribution of agrochemicals, and a number of researchers have developed experimental methods for in vitro distribution. These methods involve the determination of saline-blood and saline-tissue partitions; not only are they indirect, but they do not yield the required in vivo distribution. The authors set out equations for gas-tissue and blood-tissue distribution, for partition from water into skin and for permeation from water through human skin. Together with Abraham descriptors for the agrochemicals, these equations can be used to predict values for all of these processes. The present predictions compare favourably with experimental in vivo blood-tissue distribution where available. The predictions require no more than simple arithmetic. The present method represents a much easier and much more economic way of estimating blood-tissue partitions than the method that uses saline-blood and saline-tissue partitions. It has the added advantages of yielding the required in vivo partitions and being easily extended to the prediction of partition of agrochemicals from water into skin and permeation from water through skin. © 2013 Society of Chemical Industry.

Comparison of tissue viability imaging and colorimetry: skin blanching.

Science.gov (United States)

Zhai, Hongbo; Chan, Heidi P; Farahmand, Sara; Nilsson, Gert E; Maibach, Howard I

2009-02-01

Operator-independent assessment of skin blanching is important in the development and evaluation of topically applied steroids. Spectroscopic instruments based on hand-held probes, however, include elements of operator dependence such as difference in applied pressure and probe misalignment, while laser Doppler-based methods are better suited for demonstration of skin vasodilatation than for vasoconstriction. To demonstrate the potential of the emerging technology of Tissue Viability Imaging (TiVi) in the objective and operator-independent assessment of skin blanching. The WheelsBridge TiVi600 Tissue Viability Imager was used for quantification of human skin blanching with the Minolta chromameter CR 200 as an independent colorimeter reference method. Desoximetasone gel 0.05% was applied topically on the volar side of the forearm under occlusion for 6 h in four healthy adults. In a separate study, the induction of blanching in the occlusion phase was mapped using a transparent occlusion cover. The relative uncertainty in the blanching estimate produced by the Tissue Viability Imager was about 5% and similar to that of the chromameter operated by a single user and taking the a(*) parameter as a measure of blanching. Estimation of skin blanching could also be performed in the presence of a transient paradoxical erythema, using the integrated TiVi software. The successive induction of skin blanching during the occlusion phase could readily be mapped by the Tissue Viability Imager. TiVi seems to be suitable for operator-independent and remote mapping of human skin blanching, eliminating the main disadvantages of methods based on hand-held probes.

Radio-sterilization and processing of frozen human skin

International Nuclear Information System (INIS)

Zarate S, Herman; Aguirre H, Paulina; Silva R, Samy; Hitschfeld G, Mario

2006-01-01

The Laboratory of Radio-sterilized Biological Tissues Processing (LPTR) belonging to the Chilean Commission of Nuclear Energy and the International Atomic Energy Agency have played a paramount role in our country, concerning the biological tissue processing, which can be radio-sterilized as human skin, pig skin, amniotic membrane, human bone and bovine bone. The frozen radio.-sterilized human skin processing began in 2001, by means of putting into practice the knowledge acquired in training courses through the IAEA and the experience transferred by experts who visited our laboratory. The human skin processing of dead donor can be divided into 6 stages: a) Profuse washing with physiological sterilized serum in to remove the microorganisms, chemical and pharmacological compounds; b) immersion in glycerol solution at 10% to better keep the stored tissues; c) packing, to avoid post manipulation of the sterilized tissue; d) microbiological controls which allow and guarantee a sterility assurance level of 10 6 ; e) radio-sterilization, technique that consists of exposing the grafts to electromagnetic gamma waves which eliminate the microorganisms of the tissue, f) and finally, dispatching and liberation of the frozen sterilized human skin for its clinical use in different centers that take care of burned people. The LPTR receives feedback from surgeons who have used these tissues in order to improve the processing stages based in an integral quality system ISO 9001.2000. The State Health System in our country counts on limited and scarce resources to implement synthetic substitutes that is why It is considered necessary to spread the use of these noble tissues which have sterility assurance and they are processed at low price

Polarimetry based partial least square classification of ex vivo healthy and basal cell carcinoma human skin tissues.

Science.gov (United States)

Ahmad, Iftikhar; Ahmad, Manzoor; Khan, Karim; Ikram, Masroor

2016-06-01

Optical polarimetry was employed for assessment of ex vivo healthy and basal cell carcinoma (BCC) tissue samples from human skin. Polarimetric analyses revealed that depolarization and retardance for healthy tissue group were significantly higher (ppolarimetry together with PLS statistics hold promise for automated pathology classification. Copyright © 2016 Elsevier B.V. All rights reserved.

Redox proteomic evaluation of oxidative modification and recovery in a 3D reconstituted human skin tissue model exposed to UVB.

Science.gov (United States)

Dyer, J M; Haines, S R; Thomas, A; Wang, W; Walls, R J; Clerens, S; Harland, D P

2017-04-01

Exposure to UV in humans resulting in sunburn triggers a complex series of events that are a mix of immediate and delayed damage mediation and healing. While studies on the effects of UV exposure on DNA damage and repair have been reported, changes in the oxidative modification of skin proteins are poorly understood at the molecular level, despite the important role played by structural proteins in skin tissue, and the effect of the integrity of these proteins on skin appearance and health. Proteomic molecular mapping of oxidation was here applied to try to enhance understanding of skin damage and recovery from oxidative damage and UVB exposure. A redox proteomic-based approach was applied to evaluating skin protein modification when exposed to varying doses of UVB after initial oxidative stress, via tracking changes in protein oxidation during the healing process in vitro using a full-thickness reconstituted human skin tissue model. Bioassays and structural evaluation confirmed that our cultured skin tissues underwent a normal physiological response to UVB exposure. A set of potential skin marker peptides was generated, for use in tracking skin protein oxidative modification. Exposure to UVB after thermal oxidative stress was found to result in higher levels of skin protein oxidation than a non-irradiated control for up to seven days after exposure. Recovery of the skin proteins from oxidative stress, as assessed by the overall protein oxidation levels, was found to be impaired by UVB exposure. Oxidative modification was largely observed in skin structural proteins. Exposure of skin proteins to UVB exacerbates oxidative damage to structural skin proteins, with higher exposure levels leading to increasingly impaired recovery from this damage. This has potential implications for the functional performance of the proteins and inter-related skin health and cosmetic appearance. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Preliminary observations on differences in the Raman spectra of cancerous and noncancerous cells and connective tissue of human skin

Science.gov (United States)

Short, Michael A.; Lui, Harvey; McLean, David I.; Zeng, Haishan; Alajlan, Abdulmajeed; Chen, Michael X.

2005-04-01

A less invasive method of reliably detecting skin cancers is required. Raman spectroscopy is just one of several spectroscopic methods that look promising, but are not yet sufficiently reliable. More information is needed on how and why the Raman spectra of cancerous skin tissue is different from its normal counterpart. We have used confocal micro-Raman spectroscopy with a spatial resolution of about a micron to obtain spectra of unstained thin sections of human skin. We found that there were clear differences in the Raman spectra between cancerous and non-cancerous tissue both in cells and in the connective tissue. The DNA contribution to the spectra was generally stronger in malignant cells than normal ones. In regions of the dermis far away from the tumor one obtains the usual collagen spectra of normal skin, but adjacent to the tumor the spectra no longer appeared to be those of native collagen.

Finite element model to study temperature distribution in skin and deep tissues of human limbs.

Science.gov (United States)

Agrawal, Mamta; Pardasani, K R

2016-12-01

The temperature of body tissues is viewed as an indicator of tissue response in clinical applications since ancient times. The tissue temperature depends on various physical and physiological parameters like blood flow, metabolic heat generation, thermal conductivity of tissues, shape and size of organs etc. In this paper a finite element model has been proposed to study temperature distribution in skin and deep tissues of human limbs. The geometry of human limb is taken as elliptical tapered shape. It is assumed that outer surface of the limb is exposed to the environment. The appropriate boundary conditions have been framed based on physical conditions of the problem. The model has been developed for a three dimensional steady state case. Hexahedral circular sectoral elements are used to discretize the region. The results have been computed to obtain temperature profiles and study the relation of tissue temperature with the parameters like atmospheric temperature, rate of evaporation, thickness of tissues layers and shape of the limb. Copyright © 2016 Elsevier Ltd. All rights reserved.

[The clinical use of cryopreserved human skin allografts for transplantation].

Science.gov (United States)

Martínez-Flores, Francisco; Chacón-Gómez, María; Madinaveitia-Villanueva, Juan Antonio; Barrera-Lopez, Araceli; Aguirre-Cruz, Lucinda; Querevalu-Murillo, Walter

2015-01-01

The biological recovery of human skin allografts is the gold standard for preservation in Skin Banks. However, there is no worldwide consensus about specific allocation criteria for preserved human skin allografts with living cells. A report is presented on the results of 5 years of experience of using human skin allografts in burned patient in the Skin and Tissue Bank at the "Instituto Nacional de Rehabilitacion" The human skin allografts were obtained from multi-organ donors. processed and preserved at -80 °C for 12 months. Allocation criteria were performed according to blood type match, clinical history, and burned body surface. Up to now, the Skin and Tissue Bank at 'Instituto Nacional de Rehabilitacion" has processed and recovered 125,000 cm(2) of human skin allografts. It has performed 34 surgical implants on 21 burned patients. The average of burn body surface was 59.2%. More than two-thirds (67.7%) of recipients of skin allografts were matched of the same to type blood of the donor, and 66.6% survived after 126 days hospital stay. It is proposed to consider recipient's blood group as allocation criteria to assign tissue; and use human skin allografts on patiens affected with burns over 30% of body surface (according the "rule of the 9"). Copyright © 2015 Academia Mexicana de Cirugía A.C. Published by Masson Doyma México S.A. All rights reserved.

Biothermomechanical behavior of skin tissue

Institute of Scientific and Technical Information of China (English)

F.Xu; T.J.Lu; K.A.Seffen

2008-01-01

Advances in laser,microwave and similar tech nologies have led to recent developments of thermal treatments involving skin tissue.The effectiveness of these treatments is governed by the coupled thermal,mechanical,biological and neural responses of the affected tissue:a favorable interaction results in a procedure with relatively little pain and no lasting side effects.Currently,even though each behavioral facet is to a certain extent established and understood,none exists to date in the interdisciplinarv area.A highly interdisciplinary approach is required for studying the biothermomechanical behavior of skin,involving bioheat transfer.biomechanics and physiology.A comprehensive literature review penrtinent to the subject is presented in this paper,covering four subject areas:(a)skin structure,(b)skin bioheat transfer and thermal damage,(c)skin biomechanics,and(d)skin biothermomechanics.The major problems,issues,and topics for further studies are also outlined.This review finds that significant advances in each of these aspects have been achieved in recent years.Although focus is placed upon the biothermomechanical behavior of skin tissue,the fundamental concepts and methodologies reviewed in this paper may also be applicable for studying other soft tissues.

Investigation of the effect of hydration on dermal collagen in ex vivo human skin tissue using second harmonic generation microscopy

Science.gov (United States)

Samatham, Ravikant; Wang, Nicholas K.; Jacques, Steven L.

2016-02-01

Effect of hydration on the dermal collagen structure in human skin was investigated using second harmonic generation microscopy. Dog ears from the Mohs micrographic surgery department were procured for the study. Skin samples with subject aged between 58-90 years old were used in the study. Three dimensional Multiphoton (Two-photon and backward SHG) control data was acquired from the skin samples. After the control measurement, the skin tissue was either soaked in deionized water for 2 hours (Hydration) or kept at room temperature for 2 hours (Desiccation), and SHG data was acquired. The data was normalized for changes in laser power and detector gain. The collagen signal per unit volume from the dermis was calculated. The desiccated skin tissue gave higher backward SHG compared to respective control tissue, while hydration sample gave a lower backward SHG. The collagen signal decreased with increase in hydration of the dermal collagen. Hydration affected the packing of the collagen fibrils causing a change in the backward SHG signal. In this study, the use of multiphoton microscopy to study the effect of hydration on dermal structure was demonstrated in ex vivo tissue.

Characterization of a Cryopreserved Split-Thickness Human Skin Allograft-TheraSkin.

Science.gov (United States)

Landsman, Adam; Rosines, Eran; Houck, Amanda; Murchison, Angela; Jones, Alyce; Qin, Xiaofei; Chen, Silvia; Landsman, Arnold R

2016-09-01

The purpose of this study was to examine the characteristics of a cryopreserved split-thickness skin allograft produced from donated human skin and compare it with fresh, unprocessed human split-thickness skin. Cutaneous wound healing is a complex and organized process, where the body re-establishes the integrity of the injured tissue. However, chronic wounds, such as diabetic or venous stasis ulcers, are difficult to manage and often require advanced biologics to facilitate healing. An ideal wound care product is able to directly influence wound healing by introducing biocompatible extracellular matrices, growth factors, and viable cells to the wound bed. TheraSkin (processed by LifeNet Health, Virginia Beach, Virginia, and distributed by Soluble Systems, Newport News, Virginia) is a minimally manipulated, cryopreserved split-thickness human skin allograft, which contains natural extracellular matrices, native growth factors, and viable cells. The authors characterized TheraSkin in terms of the collagen and growth factor composition using ELISA, percentage of apoptotic cells using TUNEL analysis, and cellular viability using alamarBlue assay (Thermo Fisher Scientific, Waltham, Massachusetts), and compared these characteristics with fresh, unprocessed human split-thickness skin. It was found that the amount of the type I and type III collagen, as well as the ratio of type I to type III collagen in TheraSkin, is equivalent to fresh unprocessed human split-thickness skin. Similar quantities of vascular endothelial growth factor, insulinlike growth factor 1, fibroblast growth factor 2, and transforming growth factor β1 were detected in TheraSkin and fresh human skin. The average percent of apoptotic cells was 34.3% and 3.1% for TheraSkin and fresh skin, respectively. Cellular viability was demonstrated in both TheraSkin and fresh skin.

3D cell printing of in vitro stabilized skin model and in vivo pre-vascularized skin patch using tissue-specific extracellular matrix bioink: A step towards advanced skin tissue engineering.

Science.gov (United States)

Kim, Byoung Soo; Kwon, Yang Woo; Kong, Jeong-Sik; Park, Gyu Tae; Gao, Ge; Han, Wonil; Kim, Moon-Bum; Lee, Hyungseok; Kim, Jae Ho; Cho, Dong-Woo

2018-06-01

3D cell-printing technique has been under spotlight as an appealing biofabrication platform due to its ability to precisely pattern living cells in pre-defined spatial locations. In skin tissue engineering, a major remaining challenge is to seek for a suitable source of bioink capable of supporting and stimulating printed cells for tissue development. However, current bioinks for skin printing rely on homogeneous biomaterials, which has several shortcomings such as insufficient mechanical properties and recapitulation of microenvironment. In this study, we investigated the capability of skin-derived extracellular matrix (S-dECM) bioink for 3D cell printing-based skin tissue engineering. S-dECM was for the first time formulated as a printable material and retained the major ECM compositions of skin as well as favorable growth factors and cytokines. This bioink was used to print a full thickness 3D human skin model. The matured 3D cell-printed skin tissue using S-dECM bioink was stabilized with minimal shrinkage, whereas the collagen-based skin tissue was significantly contracted during in vitro tissue culture. This physical stabilization and the tissue-specific microenvironment from our bioink improved epidermal organization, dermal ECM secretion, and barrier function. We further used this bioink to print 3D pre-vascularized skin patch able to promote in vivo wound healing. In vivo results revealed that endothelial progenitor cells (EPCs)-laden 3D-printed skin patch together with adipose-derived stem cells (ASCs) accelerates wound closure, re-epithelization, and neovascularization as well as blood flow. We envision that the results of this paper can provide an insightful step towards the next generation source for bioink manufacturing. Copyright © 2018 Elsevier Ltd. All rights reserved.

Quantification of thermal damage in skin tissue

Institute of Scientific and Technical Information of China (English)

Xu Feng; Wen Ting; Lu Tianjian; Seffen Keith

2008-01-01

Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great problem for burn patients. Thus, it is of great importance to quantify the thermal damage in skin tissue. In this paper, the available models and experimental methods for quantification of thermal damage in skin tissue are discussed.

Next generation human skin constructs as advanced tools for drug development.

Science.gov (United States)

Abaci, H E; Guo, Zongyou; Doucet, Yanne; Jacków, Joanna; Christiano, Angela

2017-11-01

Many diseases, as well as side effects of drugs, manifest themselves through skin symptoms. Skin is a complex tissue that hosts various specialized cell types and performs many roles including physical barrier, immune and sensory functions. Therefore, modeling skin in vitro presents technical challenges for tissue engineering. Since the first attempts at engineering human epidermis in 1970s, there has been a growing interest in generating full-thickness skin constructs mimicking physiological functions by incorporating various skin components, such as vasculature and melanocytes for pigmentation. Development of biomimetic in vitro human skin models with these physiological functions provides a new tool for drug discovery, disease modeling, regenerative medicine and basic research for skin biology. This goal, however, has long been delayed by the limited availability of different cell types, the challenges in establishing co-culture conditions, and the ability to recapitulate the 3D anatomy of the skin. Recent breakthroughs in induced pluripotent stem cell (iPSC) technology and microfabrication techniques such as 3D-printing have allowed for building more reliable and complex in vitro skin models for pharmaceutical screening. In this review, we focus on the current developments and prevailing challenges in generating skin constructs with vasculature, skin appendages such as hair follicles, pigmentation, immune response, innervation, and hypodermis. Furthermore, we discuss the promising advances that iPSC technology offers in order to generate in vitro models of genetic skin diseases, such as epidermolysis bullosa and psoriasis. We also discuss how future integration of the next generation human skin constructs onto microfluidic platforms along with other tissues could revolutionize the early stages of drug development by creating reliable evaluation of patient-specific effects of pharmaceutical agents. Impact statement Skin is a complex tissue that hosts various

Design and fabrication of human skin by three-dimensional bioprinting.

Science.gov (United States)

Lee, Vivian; Singh, Gurtej; Trasatti, John P; Bjornsson, Chris; Xu, Xiawei; Tran, Thanh Nga; Yoo, Seung-Schik; Dai, Guohao; Karande, Pankaj

2014-06-01

Three-dimensional (3D) bioprinting, a flexible automated on-demand platform for the free-form fabrication of complex living architectures, is a novel approach for the design and engineering of human organs and tissues. Here, we demonstrate the potential of 3D bioprinting for tissue engineering using human skin as a prototypical example. Keratinocytes and fibroblasts were used as constituent cells to represent the epidermis and dermis, and collagen was used to represent the dermal matrix of the skin. Preliminary studies were conducted to optimize printing parameters for maximum cell viability as well as for the optimization of cell densities in the epidermis and dermis to mimic physiologically relevant attributes of human skin. Printed 3D constructs were cultured in submerged media conditions followed by exposure of the epidermal layer to the air-liquid interface to promote maturation and stratification. Histology and immunofluorescence characterization demonstrated that 3D printed skin tissue was morphologically and biologically representative of in vivo human skin tissue. In comparison with traditional methods for skin engineering, 3D bioprinting offers several advantages in terms of shape- and form retention, flexibility, reproducibility, and high culture throughput. It has a broad range of applications in transdermal and topical formulation discovery, dermal toxicity studies, and in designing autologous grafts for wound healing. The proof-of-concept studies presented here can be further extended for enhancing the complexity of the skin model via the incorporation of secondary and adnexal structures or the inclusion of diseased cells to serve as a model for studying the pathophysiology of skin diseases.

Immune Cell-Supplemented Human Skin Model for Studying Fungal Infections.

Science.gov (United States)

Kühbacher, Andreas; Sohn, Kai; Burger-Kentischer, Anke; Rupp, Steffen

2017-01-01

Human skin is a niche for various fungal species which either colonize the surface of this tissue as commensals or, primarily under conditions of immunosuppression, invade the skin and cause infection. Here we present a method for generation of a human in vitro skin model supplemented with immune cells of choice. This model represents a complex yet amenable tool to study molecular mechanisms of host-fungi interactions at human skin.

Experimental study on tissue phantoms to understand the effect of injury and suturing on human skin mechanical properties.

Science.gov (United States)

Chanda, Arnab; Unnikrishnan, Vinu; Flynn, Zachary; Lackey, Kim

2017-01-01

Skin injuries are the most common type of injuries occurring in day-to-day life. A skin injury usually manifests itself in the form of a wound or a cut. While a shallow wound may heal by itself within a short time, deep wounds require surgical interventions such as suturing for timely healing. To date, suturing practices are based on a surgeon's experience and may vary widely from one situation to another. Understanding the mechanics of wound closure and suturing of the skin is crucial to improve clinical suturing practices and also to plan automated robotic surgeries. In the literature, phenomenological two-dimensional computational skin models have been developed to study the mechanics of wound closure. Additionally, the effect of skin pre-stress (due to the natural tension of the skin) on wound closure mechanics has been studied. However, in most of these analyses, idealistic two-dimensional skin geometries, materials and loads have been assumed, which are far from reality, and would clearly generate inaccurate quantitative results. In this work, for the first time, a biofidelic human skin tissue phantom was developed using a two-part silicone material. A wound was created on the phantom material and sutures were placed to close the wound. Uniaxial mechanical tests were carried out on the phantom specimens to study the effect of varying wound size, quantity, suture and pre-stress on the mechanical behavior of human skin. Also, the average mechanical behavior of the human skin surrogate was characterized using hyperelastic material models, in the presence of a wound and sutures. To date, such a robust experimental study on the effect of injury and sutures on human skin mechanics has not been attempted. The results of this novel investigation will provide important guidelines for surgical planning and validation of results from computational models in the future.

MicroRNAs in skin tissue engineering.

Science.gov (United States)

Miller, Kyle J; Brown, David A; Ibrahim, Mohamed M; Ramchal, Talisha D; Levinson, Howard

2015-07-01

35.2 million annual cases in the U.S. require clinical intervention for major skin loss. To meet this demand, the field of skin tissue engineering has grown rapidly over the past 40 years. Traditionally, skin tissue engineering relies on the "cell-scaffold-signal" approach, whereby isolated cells are formulated into a three-dimensional substrate matrix, or scaffold, and exposed to the proper molecular, physical, and/or electrical signals to encourage growth and differentiation. However, clinically available bioengineered skin equivalents (BSEs) suffer from a number of drawbacks, including time required to generate autologous BSEs, poor allogeneic BSE survival, and physical limitations such as mass transfer issues. Additionally, different types of skin wounds require different BSE designs. MicroRNA has recently emerged as a new and exciting field of RNA interference that can overcome the barriers of BSE design. MicroRNA can regulate cellular behavior, change the bioactive milieu of the skin, and be delivered to skin tissue in a number of ways. While it is still in its infancy, the use of microRNAs in skin tissue engineering offers the opportunity to both enhance and expand a field for which there is still a vast unmet clinical need. Here we give a review of skin tissue engineering, focusing on the important cellular processes, bioactive mediators, and scaffolds. We further discuss potential microRNA targets for each individual component, and we conclude with possible future applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Use of Clotted Human Plasma and Aprotinin in Skin Tissue Engineering: A Novel Approach to Engineering Composite Skin on a Porous Scaffold.

Science.gov (United States)

Paul, Michelle; Kaur, Pritinder; Herson, Marisa; Cheshire, Perdita; Cleland, Heather; Akbarzadeh, Shiva

2015-10-01

Tissue-engineered composite skin is a promising therapy for the treatment of chronic and acute wounds, including burns. Providing the wound bed with a dermal scaffold populated by autologous dermal and epidermal cellular components can further entice host cell infiltration and vascularization to achieve permanent wound closure in a single stage. However, the high porosity and the lack of a supportive basement membrane in most commercially available dermal scaffolds hinders organized keratinocyte proliferation and stratification in vitro and may delay re-epithelization in vivo. The objective of this study was to develop a method to enable the in vitro production of a human skin equivalent (HSE) that included a porous scaffold and dermal and epidermal cells expanded ex vivo, with the potential to be used for definitive treatment of skin defects in a single procedure. A collagen-glycosaminoglycan dermal scaffold (Integra(®)) was populated with adult fibroblasts. A near-normal skin architecture was achieved by the addition of coagulated human plasma to the fibroblast-populated scaffold before seeding cultured keratinocytes. This resulted in reducing scaffold pore size and improving contact surfaces. Skin architecture and basement membrane formation was further improved by the addition of aprotinin (a serine protease inhibitor) to the culture media to inhibit premature clot digestion. Histological assessment of the novel HSE revealed expression of keratin 14 and keratin 10 similar to native skin, with a multilayered neoepidermis morphologically comparable to human skin. Furthermore, deposition of collagen IV and laminin-511 were detected by immunofluorescence, indicating the formation of a continuous basement membrane at the dermal-epidermal junction. The proposed method was efficient in producing an in vitro near native HSE using the chosen off-the-shelf porous scaffold (Integra). The same principles and promising outcomes should be applicable to other biodegradable

In vitro prediction of in vivo skin damage associated with the wiping of dry tissue against skin.

Science.gov (United States)

Koenig, David W; Dvoracek, Barb; Vongsa, Rebecca

2013-02-01

The ideal gentle cleansing product is one that effectively removes soils while minimizing damage to the skin. Thus, measuring physical abrasion caused by cleansing tissues is critical to the continued development of gentle cleansing products. Current analysis of cleansing materials for skin gentleness is time consuming and requires expensive human subject testing. This report describes the development of a rapid and inexpensive bench assay for the assessment of skin abrasion caused by wiping. Coefficient of friction (COF) evaluations using bench methods were compared with results from clinical studies of repeated wiping and with confocal visualizations of excised skin. A Monitor/Slip and Friction instrument (model 32-06; TMI, Amityville, NY, USA) was used to measure tissue friction on simulated skin (Vitro-Skin, N19-5X; IMS, Milford, CT, USA). Clinical data from a 4-day repetitive forearm wiping study measuring transepidermal water loss (TEWL) in 30 subjects was compared with results from the bench top assay. In addition, excised skin samples were also treated using the COF bench assay and examined using confocal microscopy to visualize stratum corneum damage caused by wiping. Using the bench COF assay, we were able to distinguish between bath tissue codes by comparing average static friction value (ASFV) for the test codes, where lower ASFV indicated less abrasive tissue. The ASFV followed the same gentleness trend observed in the clinical study. Confocal microscopy of excised skin wiped with the same materials indicated stratum corneum damage consistent with the bench COF and clinical TEWL observations. We observed significant correlation between bench and clinical methods for measuring skin damage caused by wiping of skin with tissue. The bench method will facilitate rapid and inexpensive skin gentleness assessment of cleansing materials. © 2012 John Wiley & Sons A/S.

Diffusion of [2-14C]diazepam across hairless mouse skin and human skin

International Nuclear Information System (INIS)

Koch, R.L.; Palicharla, P.; Groves, M.J.

1987-01-01

The objectives of this study were to investigate the absorption of diazepam applied topically to the hairless mouse in vivo and to determine the diffusion of diazepam across isolated hairless mouse skin and human skin. [ 14 C]Diazepam was readily absorbed after topical administration to the intact hairless mouse, a total of 75.8% of the 14 C-label applied being recovered in urine and feces. Diazepam was found to diffuse across human and hairless mouse skin unchanged in experiments with twin-chambered diffusion cells. The variation in diffusion rate or the flux for both human and mouse tissues was greater among specimens than between duplicate or triplicate trials for a single specimen. Fluxes for mouse skin (stratum corneum, epidermis, and dermis) were greater than for human skin (stratum corneum and epidermis): 0.35-0.61 microgram/cm2/h for mouse skin vs 0.24-0.42 microgram/cm2/h for human skin. The permeability coefficients for mouse skin ranged from 1.4-2.4 X 10(-2)cm/h compared with 0.8-1.4 X 10(-2)cm/h for human skin. Although human stratum corneum is almost twice the thickness of that of the hairless mouse, the diffusion coefficients for human skin were 3-12 times greater (0.76-3.31 X 10(-6) cm2/h for human skin vs 0.12-0.27 X 10(-6) cm2/h for hairless mouse) because of a shorter lag time for diffusion across human skin. These differences between the diffusion coefficients and diffusion rates (or permeability coefficients) suggest that the presence of the dermis may present some barrier properties. In vitro the dermis may require complete saturation before the diazepam can be detected in the receiving chamber

Expression of C4.4A in an in Vitro Human Tissue-Engineered Skin Model

DEFF Research Database (Denmark)

Jacobsen, Benedikte; Larouche, Danielle; Rochette-Drouin, Olivier

2017-01-01

, the biological function of C4.4A remains unknown. To enable further studies, we evaluated the expression of C4.4A in monolayer cultures of normal human keratinocytes and in tissue-engineered skin substitutes (TESs) produced by the self-assembly approach, which allow the formation of a fully differentiated...... epidermis tissue. Results showed that, in monolayer, C4.4A was highly expressed in the centre of keratinocyte colonies at cell-cell contacts areas, while some cells located at the periphery presented little C4.4A expression. In TES, emergence of C4.4A expression coincided with the formation of the stratum...

Isolation of Human Skin Dendritic Cell Subsets.

Science.gov (United States)

Gunawan, Merry; Jardine, Laura; Haniffa, Muzlifah

2016-01-01

Dendritic cells (DCs) are specialized leukocytes with antigen-processing and antigen-presenting functions. DCs can be divided into distinct subsets by anatomical location, phenotype and function. In human, the two most accessible tissues to study leukocytes are peripheral blood and skin. DCs are rare in human peripheral blood (skin covering an average total surface area of 1.8 m(2) has approximately tenfold more DCs than the average 5 L of total blood volume (Wang et al., J Invest Dermatol 134:965-974, 2014). DCs migrate spontaneously from skin explants cultured ex vivo, which provide an easy method of cell isolation (Larsen et al., J Exp Med 172:1483-1493, 1990; Lenz et al., J Clin Invest 92:2587-2596, 1993; Nestle et al., J Immunol 151:6535-6545, 1993). These factors led to the extensive use of skin DCs as the "prototype" migratory DCs in human studies. In this chapter, we detail the protocols to isolate DCs and resident macrophages from human skin. We also provide a multiparameter flow cytometry gating strategy to identify human skin DCs and to distinguish them from macrophages.

In vivo study of the human skin by the method of laser-induced fluorescence spectroscopy

International Nuclear Information System (INIS)

Borisova, E.; Avramov, L.

2000-01-01

The goals of this study are to perform a preliminary evaluation of the diagnostic potential of noninvasive laser-induced auto-fluorescence spectroscopy (LIAFS) for human skin and optimize of detection and diagnosis of hollow organs and skin. In recent years, there has been growing interest in the use of laser-induced fluorescence to discriminate disease from normal surrounding tissue. The most fluorescence studies have used exogenous fluorophores of this discrimination. The laser-induced auto-fluorescence which is used for diagnosis of tissues in the human body avoids administration of any drugs. In this study a technique for optical biopsy of in vivo human skin is presented. The auto-fluorescence characterization of tissue relies on different spectral properties of tissues. It was demonstrated a differentiation between normal skin and skin with vitiligo. Two main endogenous fluorophores in the human skin account for most of the cellular auto-fluorescence for excitation wavelength 337 nm reduced from of nicotinamide adenine dinucleotide and collagen. The auto-fluorescence spectrum of human skin depend on main internal absorbers which are blood and melanin. In this study was described the effect caused by blood and melanin content on the shape of the auto-fluorescence spectrum of human skin. Human skin fluorescence spectrum might provide dermatologists with important information and such investigations are successfully used now in skin disease diagnostics, in investigation of the environmental factor impact or for evaluation of treatment efficiency. (authors)

3D imaging of cleared human skin biopsies using light-sheet microscopy: A new way to visualize in-depth skin structure.

Science.gov (United States)

Abadie, S; Jardet, C; Colombelli, J; Chaput, B; David, A; Grolleau, J-L; Bedos, P; Lobjois, V; Descargues, P; Rouquette, J

2018-05-01

Human skin is composed of the superimposition of tissue layers of various thicknesses and components. Histological staining of skin sections is the benchmark approach to analyse the organization and integrity of human skin biopsies; however, this approach does not allow 3D tissue visualization. Alternatively, confocal or two-photon microscopy is an effective approach to perform fluorescent-based 3D imaging. However, owing to light scattering, these methods display limited light penetration in depth. The objectives of this study were therefore to combine optical clearing and light-sheet fluorescence microscopy (LSFM) to perform in-depth optical sectioning of 5 mm-thick human skin biopsies and generate 3D images of entire human skin biopsies. A benzyl alcohol and benzyl benzoate solution was used to successfully optically clear entire formalin fixed human skin biopsies, making them transparent. In-depth optical sectioning was performed with LSFM on the basis of tissue-autofluorescence observations. 3D image analysis of optical sections generated with LSFM was performed by using the Amira ® software. This new approach allowed us to observe in situ the different layers and compartments of human skin, such as the stratum corneum, the dermis and epidermal appendages. With this approach, we easily performed 3D reconstruction to visualise an entire human skin biopsy. Finally, we demonstrated that this method is useful to visualise and quantify histological anomalies, such as epidermal hyperplasia. The combination of optical clearing and LSFM has new applications in dermatology and dermatological research by allowing 3D visualization and analysis of whole human skin biopsies. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Spectra from 2.5-15 μm of tissue phantom materials, optical clearing agents and ex vivo human skin: implications for depth profiling of human skin

International Nuclear Information System (INIS)

Viator, John A; Choi, Bernard; Peavy, George M; Kimel, Sol; Nelson, J Stuart

2003-01-01

Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measurement of tissue phantoms has raised the question of their infrared absorption spectrum. We used Fourier transform infrared spectroscopy in attenuated total reflection mode to measure the infrared absorption spectra, in the range of 2-15 μm, of water, polyacrylamide, Intralipid, collagen gels, four hyperosmotic clearing agents (glycerol, 1,3-butylene glycol, trimethylolpropane, Topicare TM ), and ex vivo human stratum corneum and dermis. The absorption spectra of the phantom materials were similar to that of water, although additional structure was noted in the range of 6-10 μm. The absorption spectra of the clearing agents were more complex, with molecular absorption bands dominating between 6 and 12 μm. Dermis was similar to water, with collagen structure evident in the 6-10 μm range. Stratum corneum had a significantly lower absorption than dermis due to a lower content of water. These results suggest that the assumption of water-dominated absorption in the 2.5-6 μm range is valid. At longer wavelengths, clearing agent absorption spectra differ significantly from the water spectrum. This spectral information can be used in pulsed photothermal radiometry or utilized in the interpretation of reconstructions in which a constant μ ir is used. In such cases, overestimating μ ir will underestimate chromophore depth and vice versa, although the effect is dependent on actual chromophore depth. (note)

Quantification of thermal damage in skin tissue

Institute of Scientific and Technical Information of China (English)

徐峰; 文婷; 卢天健; Seffen; Keith

2008-01-01

Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great...

An in vitro model for detecting skin irritants: methyl green-pyronine staining of human skin explant cultures

NARCIS (Netherlands)

Jacobs, J. J. L.; Lehé, C.; Cammans, K. D. A.; Das, P. K.; Elliott, G. R.

2002-01-01

We evaluated the potential of human organotypic skin explant cultures (hOSECs) for screening skin irritants. Test chemicals were applied to the epidermis of the skin explants which were incubated for 4, 24 or 48 h in tissue culture medium. A decrease in epidermal RNA staining, visualised in frozen

Proof-of-concept: 3D bioprinting of pigmented human skin constructs.

Science.gov (United States)

Ng, Wei Long; Qi, Jovina Tan Zhi; Yeong, Wai Yee; Naing, May Win

2018-01-23

Three-dimensional (3D) pigmented human skin constructs have been fabricated using a 3D bioprinting approach. The 3D pigmented human skin constructs are obtained from using three different types of skin cells (keratinocytes, melanocytes and fibroblasts from three different skin donors) and they exhibit similar constitutive pigmentation (pale pigmentation) as the skin donors. A two-step drop-on-demand bioprinting strategy facilitates the deposition of cell droplets to emulate the epidermal melanin units (pre-defined patterning of keratinocytes and melanocytes at the desired positions) and manipulation of the microenvironment to fabricate 3D biomimetic hierarchical porous structures found in native skin tissue. The 3D bioprinted pigmented skin constructs are compared to the pigmented skin constructs fabricated by conventional a manual-casting approach; in-depth characterization of both the 3D pigmented skin constructs has indicated that the 3D bioprinted skin constructs have a higher degree of resemblance to native skin tissue in term of the presence of well-developed stratified epidermal layers and the presence of a continuous layer of basement membrane proteins as compared to the manually-cast samples. The 3D bioprinting approach facilitates the development of 3D in vitro pigmented human skin constructs for potential toxicology testing and fundamental cell biology research.

The Role of Carotenoids in Human Skin

Directory of Open Access Journals (Sweden)

Theognosia Vergou

2011-12-01

Full Text Available The human skin, as the boundary organ between the human body and the environment, is under the constant influence of free radicals (FR, both from the outside in and from the inside out. Carotenoids are known to be powerful antioxidant substances playing an essential role in the reactions of neutralization of FR (mainly reactive oxygen species ROS. Carotenoid molecules present in the tissue are capable of neutralizing several attacks of FR, especially ROS, and are then destroyed. Human skin contains carotenoids, such as α-, γ-, β-carotene, lutein, zeaxanthin, lycopene and their isomers, which serve the living cells as a protection against oxidation. Recent studies have reported the possibility to investigate carotenoids in human skin quickly and non-invasively by spectroscopic means. Results obtained from in-vivo studies on human skin have shown that carotenoids are vital components of the antioxidative protective system of the human skin and could serve as marker substances for the overall antioxidative status. Reflecting the nutritional and stress situation of volunteers, carotenoids must be administered by means of antioxidant-rich products, e.g., in the form of fruit and vegetables. Carotenoids are degraded by stress factors of any type, inter alia, sun radiation, contact with environmental hazards, illness, etc. The kinetics of the accumulation and degradation of carotenoids in the skin have been investigated.

First donation of human skin obtained from corpse

International Nuclear Information System (INIS)

Reyes F, M.L.; Luna Z, D.

2007-01-01

The first donation of human skin coming from a cadaverous donor was obtained in the State of Mexico. The skin was obtained of a 34 year-old multi organic donor, the extraction of the same was carried out in an operating theatre by medical personnel, supported by personal of the Radio sterilized Tissue Bank (BTR) of the ININ. The skin was transported to the BTR for it processing. (Author)

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing

Energy Technology Data Exchange (ETDEWEB)

Sharma, Rakesh, E-mail: rs05h@fsu.ed [Departments of Chemical Engineering and Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL 32310 (United States)

2010-07-21

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Skin age testing criteria: characterization of human skin structures by 500 MHz MRI multiple contrast and image processing

International Nuclear Information System (INIS)

Sharma, Rakesh

2010-01-01

Ex vivo magnetic resonance microimaging (MRM) image characteristics are reported in human skin samples in different age groups. Human excised skin samples were imaged using a custom coil placed inside a 500 MHz NMR imager for high-resolution microimaging. Skin MRI images were processed for characterization of different skin structures. Contiguous cross-sectional T1-weighted 3D spin echo MRI, T2-weighted 3D spin echo MRI and proton density images were compared with skin histopathology and NMR peaks. In all skin specimens, epidermis and dermis thickening and hair follicle size were measured using MRM. Optimized parameters TE and TR and multicontrast enhancement generated better MRI visibility of different skin components. Within high MR signal regions near to the custom coil, MRI images with short echo time were comparable with digitized histological sections for skin structures of the epidermis, dermis and hair follicles in 6 (67%) of the nine specimens. Skin % tissue composition, measurement of the epidermis, dermis, sebaceous gland and hair follicle size, and skin NMR peaks were signatures of skin type. The image processing determined the dimensionality of skin tissue components and skin typing. The ex vivo MRI images and histopathology of the skin may be used to measure the skin structure and skin NMR peaks with image processing may be a tool for determining skin typing and skin composition.

Validation of radiosterilization dose of human skin dressings for burnt treatment: preliminary study

International Nuclear Information System (INIS)

Castro, E.

2008-01-01

Full text: Due to the need for better materials to treat burnt patients, the Peruvian Institute of Nuclear Energy (IPEN) and the Rosa Guerzoni Chambergo Tissue Bank are collaborating for developing human skin dressings. Skin was procured from living donors, who surgically were performed a dermolipectomy. Exclusion criteria, stated by the Peruvian Organization for Transplant and Donation were observed. Glycerolized human skin dressings were processed at the tissue bank and sent to IPEN, where the gamma irradiation sterilizing dose was determined. The purpose of this work is to validate the radiation sterilization dose delivered to human skin dressings using the IAEA Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control. A batch of human skin dressings was tested. Average values of bioburden present in ten samples was 30 UFC/item, obtaining a sub-sterilization dose of 4 kGy. Irradiations were performed in the GammacellExcel 220. Sterility tests performed fulfilled the requirements established by the Code, achieving a validated dose value of 19.7 kGy. This preliminary study, that should be repeated in two other batches of processed human skin, allows to diminish 25 kGy the sterilizing dose to the stated above dose value, in a frame of a quality assurance system that also comprises the processes held at tissue banks previous irradiation. It also permit the availability of these materials in Peruvian hospitals. (Author)

Three-Dimensional In Vitro Skin and Skin Cancer Models Based on Human Fibroblast-Derived Matrix.

Science.gov (United States)

Berning, Manuel; Prätzel-Wunder, Silke; Bickenbach, Jackie R; Boukamp, Petra

2015-09-01

Three-dimensional in vitro skin and skin cancer models help to dissect epidermal-dermal and tumor-stroma interactions. In the model presented here, normal human dermal fibroblasts isolated from adult skin self-assembled into dermal equivalents with their specific fibroblast-derived matrix (fdmDE) over 4 weeks. The fdmDE represented a complex human extracellular matrix that was stabilized by its own heterogeneous collagen fiber meshwork, largely resembling a human dermal in vivo architecture. Complemented with normal human epidermal keratinocytes, the skin equivalent (fdmSE) thereof favored the establishment of a well-stratified and differentiated epidermis and importantly allowed epidermal regeneration in vitro for at least 24 weeks. Moreover, the fdmDE could be used to study the features of cutaneous skin cancer. Complementing fdmDE with HaCaT cells in different stages of malignancy or tumor-derived cutaneous squamous cell carcinoma cell lines, the resulting skin cancer equivalents (fdmSCEs) recapitulated the respective degree of tumorigenicity. In addition, the fdmSCE invasion phenotypes correlated with their individual degree of tissue organization, disturbance in basement membrane organization, and presence of matrix metalloproteinases. Together, fdmDE-based models are well suited for long-term regeneration of normal human epidermis and, as they recapitulate tumor-specific growth, differentiation, and invasion profiles of cutaneous skin cancer cells, also provide an excellent human in vitro skin cancer model.

Elevation of telomerase activity in chronic radiation ulcer of human skin

International Nuclear Information System (INIS)

Li Xiaoying; Zhao Po; Wang Dewen; Yang Zhixiang

1997-01-01

Objective: To investigate the levels of telomerase activity in chronic radiation ulcers of human skin and the possible relationship between the enzyme and cancer transformation. Method: Using nonisotopic telomere repeat amplification protocol (TRAP), detections were performed in 20 cases of chronic radiation ulcers of human skin, 5 cases of normal skin tissues and 5 cases of carcinoma. Results: The positive rates for telomerase activity were 30.0%(6/20), 0(0/5) and 100%(5/5) in chronic radiation ulcers of human skin, normal skin and carcinoma, respectively. The telomerase activity in radiation ulcer was weaker than in carcinoma. Conclusion: The telomerase activity assay might be used as a marker for predicting the prognosis and the effect of treatment in chronic radiation ulcer of human skin

Human adipose-derived stem cell spheroid treated with photobiomodulation irradiation accelerates tissue regeneration in mouse model of skin flap ischemia.

Science.gov (United States)

Park, In-Su; Chung, Phil-Sang; Ahn, Jin Chul; Leproux, Anais

2017-11-01

Skin flap grafting is a form of transplantation widely used in plastic surgery. However, ischemia/reperfusion injury is the main factor which reduces the survival rate of flaps following grafting. We investigated whether photobiomodulation (PBM) precondition prior to human adipose-derived stromal cell (hASC) spheroid (PBM-spheroid) transplantation improved skin tissue functional recovery by the stimulation of angiogenesis and tissue regeneration in skin flap of mice. The LED had an emission wavelength peaked at 660 ± 20 nm (6 J/cm 2 , 10 mW/cm 2 ). The expression of angiogenic growth factors in PBM-spheroid hASCs was much greater than that of not-PBM-treated spheroid or monolayer-cultured hASCs. From immunochemical staining analysis, the hASCs of PBM-spheroid were CD31 + , KDR + , and CD34 + , whereas monolayer-cultured hASCs were negative for these markers. To evaluate the therapeutic effect of hASC PBM-spheroid in vivo, PBS, monolayer-cultured hASCs, and not-PBM-spheroid were transplanted into a skin flap model. The animals were observed for 14 days. The PBM-spheroid hASCs transplanted into the skin flap ischemia differentiated into endothelial cells and remained differentiated. Transplantation of PBM-spheroid hASCs into the skin flap ischemia significantly elevated the density of vascular formations through angiogenic factors released by the skin flap ischemia and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of PBM-spheroid hASCs significantly improved functional recovery compared with PBS, monolayer-cultured hASCs, and not-PBM-spheroid treatment. These findings suggest that transplantation of PBM-spheroid hASCs may be an effective stem cell therapy for the treatment of skin flap ischemia.

Approaches to improve angiogenesis in tissue-engineered skin.

Science.gov (United States)

Sahota, Parbinder S; Burn, J Lance; Brown, Nicola J; MacNeil, Sheila

2004-01-01

A problem with tissue-engineered skin is clinical failure due to delays in vascularization. The aim of this study was to explore a number of simple strategies to improve angiogenesis/vascularization using a tissue-engineered model of skin to which small vessel human dermal microvascular endothelial cells were added. For the majority of these studies, a modified Guirguis chamber was used, which allowed the investigation of several variables within the same experiment using the same human dermis; cell type, angiogenic growth factors, the influence of keratinocytes and fibroblasts, mechanical penetration of the human dermis, the site of endothelial cell addition, and the influence of hypoxia were all examined. A qualitative scoring system was used to assess the impact of these factors on the penetration of endothelial cells throughout the dermis. Similar results were achieved using freshly isolated small vessel human dermal microvascular endothelial cells or an endothelial cell line and a minimum cell seeding density was identified. Cell penetration was not influenced by the addition of angiogenic growth factors (vascular endothelial growth factor and basic fibroblast growth factor); similarly, including epidermal keratinocytes or dermal fibroblasts did not encourage endothelial cell entry, and neither did mechanical introduction of holes throughout the dermis. Two factors were identified that significantly enhanced endothelial cell penetration into the dermis: hypoxia and the site of endothelial cell addition. Endothelial cells added from the papillary surface entered into the dermis much more effectively than when cells were added to the reticular surface of the dermis. We conclude that this model is valuable in improving our understanding of how to enhance vascularization of tissue-engineered grafts.

Collagen synthesis in human musculoskeletal tissues and skin

DEFF Research Database (Denmark)

Babraj, J A; Cuthbertson, D J R; Smith, K

2005-01-01

We have developed a direct method for the measurement of human musculoskeletal collagen synthesis on the basis of the incorporation of stable isotope-labeled proline or leucine into protein and have used it to measure the rate of synthesis of collagen in tendon, ligament, muscle, and skin....... In postabsorptive, healthy young men (28 +/- 6 yr) synthetic rates for tendon, ligament, muscle, and skin collagen were 0.046 +/- 0.005, 0.040 +/- 0.006, 0.016 +/- 0.002, and 0.037 +/- 0.003%/h, respectively (means +/- SD). In postabsorptive, healthy elderly men (70 +/- 6 yr) the rate of skeletal muscle collagen...... synthesis is greater than in the young (0.023 +/- 0.002%/h, P collagen are similar to those of mixed skeletal muscle protein in the postabsorptive state, whereas the rate for muscle collagen synthesis is much lower in both young and elderly men...

Determining the origin of cells in tissue engineered skin substitutes: a pilot study employing in situ hybridization.

Science.gov (United States)

Weber, Andreas Daniel; Pontiggia, Luca; Biedermann, Thomas; Schiestl, Clemens; Meuli, Martin; Reichmann, Ernst

2011-03-01

Definitive and high-quality coverage of large and, in particular, massive skin defects remains a significant challenge in burn as well as plastic and reconstructive surgery because of donor site shortage. A novel and promising approach to overcome these problems is tissue engineering of skin. Clearly, before eventual clinical application, engineered skin substitutes of human origin must be grafted and then evaluated in animal models. For the various tests to be conducted it is indispensable to be able to identify human cells as such in culture and also to distinguish between graft and recipient tissue after transplantation. Here we describe a tool to identify human cells in vitro and in vivo. In situ hybridization allows for the detection and localization of specific DNA or RNA sequences in morphologically preserved cells in culture or tissue sections, respectively. We used digoxigenin-labeled DNA probes corresponding to human-specific Alu repeats in order to identify human keratinocytes grown in culture together with rat cells, and also to label split and full thickness skin grafts of human origin after transplantation on immuno-incompetent rats. Digoxigenin-labeled DNA probing resulted in an intensive nuclear staining of human cells, both in culture and after transplantation onto recipient animals, while recipient animal cells (rat cells) did not stain. In situ hybridization using primate-specific Alu probes reliably allows distinguishing between cells of human and non-human origin both in culture as well as in histological sections. This method is an essential tool for those preclinical experiments (performed on non-primate animals) that must be conducted before novel tissue engineered skin substitutes might be introduced into clinical practice.

Human Skin 3D Bioprinting Using Scaffold-Free Approach.

Science.gov (United States)

Pourchet, Léa J; Thepot, Amélie; Albouy, Marion; Courtial, Edwin J; Boher, Aurélie; Blum, Loïc J; Marquette, Christophe A

2017-02-01

Organ in vitro synthesis is one of the last bottlenecks between tissue engineering and transplantation of synthetic organs. Bioprinting has proven its capacity to produce 3D objects composed of living cells but highly organized tissues such as full thickness skin (dermis + epidermis) are rarely attained. The focus of the present study is to demonstrate the capability of a newly developed ink formulation and the use of an open source printer, for the production of a really complete skin model. Proofs are given through immunostaining and electronic microscopy that the bioprinted skin presents all characteristics of human skin, both at the molecular and macromolecular level. Finally, the printability of large skin objects is demonstrated with the printing of an adult-size ear. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The isolated perfused human skin flap model: A missing link in skin penetration studies?

Science.gov (United States)

Ternullo, Selenia; de Weerd, Louis; Flaten, Gøril Eide; Holsæter, Ann Mari; Škalko-Basnet, Nataša

2017-01-01

Development of effective (trans)dermal drug delivery systems requires reliable skin models to evaluate skin drug penetration. The isolated perfused human skin flap remains metabolically active tissue for up to 6h during in vitro perfusion. We introduce the isolated perfused human skin flap as a close-to-in vivo skin penetration model. To validate the model's ability to evaluate skin drug penetration the solutions of a hydrophilic (calcein) and a lipophilic (rhodamine) fluorescence marker were applied. The skin flaps were perfused with modified Krebs-Henseleit buffer (pH7.4). Infrared technology was used to monitor perfusion and to select a well-perfused skin area for administration of the markers. Flap perfusion and physiological parameters were maintained constant during the 6h experiments and the amount of markers in the perfusate was determined. Calcein was detected in the perfusate, whereas rhodamine was not detectable. Confocal images of skin cross-sections shoved that calcein was uniformly distributed through the skin, whereas rhodamine accumulated in the stratum corneum. For comparison, the penetration of both markers was evaluated on ex vivo human skin, pig skin and cellophane membrane. The proposed perfused flap model enabled us to distinguish between the penetrations of the two markers and could be a promising close-to-in vivo tool in skin penetration studies and optimization of formulations destined for skin administration. Copyright © 2016 Elsevier B.V. All rights reserved.

In vivo evaluation of wound bed reaction and graft performance after cold skin graft storage: new targets for skin tissue engineering.

Science.gov (United States)

Knapik, Alicia; Kornmann, Kai; Kerl, Katrin; Calcagni, Maurizio; Schmidt, Christian A; Vollmar, Brigitte; Giovanoli, Pietro; Lindenblatt, Nicole

2014-01-01

Surplus harvested skin grafts are routinely stored at 4 to 6°C in saline for several days in plastic surgery. The purpose of this study was to evaluate the influence of storage on human skin graft performance in an in vivo intravital microscopic setting after transplantation. Freshly harvested human full-thickness skin grafts and split-thickness skin grafts (STSGs) after storage of 0, 3, or 7 days in moist saline at 4 to 6°C were transplanted into the modified dorsal skinfold chamber, and intravital microscopy was performed to evaluate vessel morphology and angiogenic change of the wound bed. The chamber tissue was harvested 10 days after transplantation for evaluation of tissue integrity and inflammation (hematoxylin and eosin) as well as for immunohistochemistry (human CD31, murine CD31, Ki67, Tdt-mediated dUTP-biotin nick-end labelling). Intravital microscopy results showed no differences in the host angiogenic response between fresh and preserved grafts. However, STSGs and full-thickness skin grafts exhibited a trend toward different timing and strength in capillary widening and capillary bud formation. Preservation had no influence on graft quality before transplantation, but fresh STSGs showed better quality 10 days after transplantation than 7-day preserved grafts. Proliferation and apoptosis as well as host capillary in-growth and graft capillary degeneration were equal in all groups. These results indicate that cells may activate protective mechanisms under cold conditions, allowing them to maintain function and morphology. However, rewarming may disclose underlying tissue damage. These findings could be translated to a new approach for the design of full-thickness skin substitutes.

Skin graft influence in human tissue radiated in nude mice regeneration; Influencia do enxerto de pele humana irradiada na regeneracao tecidual de camundongos nude

Energy Technology Data Exchange (ETDEWEB)

Miranda, Jurandir Tomaz de

2016-07-01

Over the last few years it has increased the interest in the human skin grafts radio sterilized for application mainly in extensive and deep burns. Because these grafts quickly grip and present antigenic lower potential, compared with other treatments used. The purpose of this study was to evaluate the histoarchitecture of human skin grafts irradiated with doses 25 kGy, 50 kGy and non-irradiated during the repair tissue process in nude mice submitted by skin grafting in the dorsal region. Three groups of animals received irradiated human skin grafts (25 kGy and 50 kGy) and non-irradiated and were euthanized on the 3{sup rd}, 7{sup th} and 21{sup th} day after the surgery. Indeed, routine histologic procedures, tissue samples were stained with hematoxylin and eosin (HE) for quantification of keratinocytes, fibroblasts, immune cells and blood vessels and immunofluorescence (IF) was performed to determine the expression human collagen type I and collagen type I and III mouse. Therefore, quantification of both the cells and the collagen types was performed by image analysis using Image-Pro Plus 6.0 software. Histologic results demonstrated at a dose of 25 kGy that human skin irradiation when grafted influences the increase in the number of cells in wound site over time and it provides better dispersion of these cells. In addition, on the 21{sup st} day, three groups of animals with human skin graft were embedded part of the graft in the healing process. On the other hand, the group not irradiated showed greater incorporation of the graft (43 %), but less production of collagen type III mouse (22 %). Since the groups irradiated skin graft showed lower graft incorporation (6 and 15%), but with greater production of collagen type III mice (35 % and 28 % to 25 kGy and 50 kGy, respectively). In conclusion, this study presented that the group irradiated to 25 kGy and it has a higher cell proliferation and vessel formation, and better remodeling of the healing area. (author)

Noninvasive imaging of human skin hemodynamics using a digital red-green-blue camera

Science.gov (United States)

Nishidate, Izumi; Tanaka, Noriyuki; Kawase, Tatsuya; Maeda, Takaaki; Yuasa, Tomonori; Aizu, Yoshihisa; Yuasa, Tetsuya; Niizeki, Kyuichi

2011-08-01

In order to visualize human skin hemodynamics, we investigated a method that is specifically developed for the visualization of concentrations of oxygenated blood, deoxygenated blood, and melanin in skin tissue from digital RGB color images. Images of total blood concentration and oxygen saturation can also be reconstructed from the results of oxygenated and deoxygenated blood. Experiments using tissue-like agar gel phantoms demonstrated the ability of the developed method to quantitatively visualize the transition from an oxygenated blood to a deoxygenated blood in dermis. In vivo imaging of the chromophore concentrations and tissue oxygen saturation in the skin of the human hand are performed for 14 subjects during upper limb occlusion at 50 and 250 mm Hg. The response of the total blood concentration in the skin acquired by this method and forearm volume changes obtained from the conventional strain-gauge plethysmograph were comparable during the upper arm occlusion at pressures of both 50 and 250 mm Hg. The results presented in the present paper indicate the possibility of visualizing the hemodynamics of subsurface skin tissue.

Characterization of SLC transporters in human skin

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Marion Alriquet

2015-03-01

Full Text Available Most identified drug transporters belong to the ATP-binding Cassette (ABC and Solute Carrier (SLC families. Recent research indicates that some of these transporters play an important role in the absorption, distribution and excretion of drugs, and are involved in clinically relevant drug-drug interactions for systemic drugs. However, very little is known about the role of drug transporters in human skin in the disposition of topically applied drugs and their involvement in drug-drug interactions. The aim of this work was to compare the expression in human skin (vs human hepatocytes and kidney of SLC transporters included in the EMA guidance as the most likely clinical sources of drug interactions. The expression of SLC transporters in human tissues was analyzed by quantitative RT-PCR. Modulation of SLC47A1 and SLC47A2 (MATE1 and MATE2 expression was analyzed after treatment of human skin in organ-culture with rifampicin and UV irradiation. The expression of SLCO2B1 (OATPB, SLCO3A1 (OATPD, SLCO4A1 (OATPE, SLC47A1 and SLC47A2 (MATE1 and MATE2 was detected in human skin, OATPE and MATE1 being the most expressed. OATPE is about 70 times more expressed in human skin than in human hepatocytes. Moreover, the expression of SLC47A1 and SLC47A2 was down-regulated after treatment with rifampicin or after exposure to UV light. The present findings demonstrate that SLCO4A1 (OATPE and SLC47A1 (MATE1 are highly expressed in human skin and suggest the involvement of SLC transporters in the disposition of topically applied drugs.

In vivo study of human skin using pulsed terahertz radiation

Energy Technology Data Exchange (ETDEWEB)

Pickwell, E [Semiconductor Physics Group, Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge CB3 0HE (United Kingdom); Cole, B E [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom); Fitzgerald, A J [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom); Pepper, M [Semiconductor Physics Group, Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge CB3 0HE (United Kingdom); Wallace, V P [TeraView Ltd, Unit 302/4 Cambridge Science Park, Cambridge CB4 0WG (United Kingdom)

2004-05-07

Studies in terahertz (THz) imaging have revealed a significant difference between skin cancer (basal cell carcinoma) and healthy tissue. Since water has strong absorptions at THz frequencies and tumours tend to have different water content from normal tissue, a likely contrast mechanism is variation in water content. Thus, we have previously devised a finite difference time-domain (FDTD) model which is able to closely simulate the interaction of THz radiation with water. In this work we investigate the interaction of THz radiation with normal human skin on the forearm and palm of the hand in vivo. We conduct the first ever systematic in vivo study of the response of THz radiation to normal skin. We take in vivo reflection measurements of normal skin on the forearm and palm of the hand of 20 volunteers. We compare individual examples of THz responses with the mean response for the areas of skin under investigation. Using the in vivo data, we demonstrate that the FDTD model can be applied to biological tissue. In particular, we successfully simulate the interaction of THz radiation with the volar forearm. Understanding the interaction of THz radiation with normal skin will form a step towards developing improved imaging algorithms for diagnostic detection of skin cancer and other tissue disorders using THz radiation.

In vivo study of human skin using pulsed terahertz radiation

International Nuclear Information System (INIS)

Pickwell, E; Cole, B E; Fitzgerald, A J; Pepper, M; Wallace, V P

2004-01-01

Studies in terahertz (THz) imaging have revealed a significant difference between skin cancer (basal cell carcinoma) and healthy tissue. Since water has strong absorptions at THz frequencies and tumours tend to have different water content from normal tissue, a likely contrast mechanism is variation in water content. Thus, we have previously devised a finite difference time-domain (FDTD) model which is able to closely simulate the interaction of THz radiation with water. In this work we investigate the interaction of THz radiation with normal human skin on the forearm and palm of the hand in vivo. We conduct the first ever systematic in vivo study of the response of THz radiation to normal skin. We take in vivo reflection measurements of normal skin on the forearm and palm of the hand of 20 volunteers. We compare individual examples of THz responses with the mean response for the areas of skin under investigation. Using the in vivo data, we demonstrate that the FDTD model can be applied to biological tissue. In particular, we successfully simulate the interaction of THz radiation with the volar forearm. Understanding the interaction of THz radiation with normal skin will form a step towards developing improved imaging algorithms for diagnostic detection of skin cancer and other tissue disorders using THz radiation

Regenerative and Antibacterial Properties of Acellular Fish Skin Grafts and Human Amnion/Chorion Membrane: Implications for Tissue Preservation in Combat Casualty Care.

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Magnusson, Skuli; Baldursson, Baldur Tumi; Kjartansson, Hilmar; Rolfsson, Ottar; Sigurjonsson, Gudmundur Fertram

2017-03-01

Improvised explosive devices and new directed energy weapons are changing warfare injuries from penetrating wounds to large surface area thermal and blast injuries. Acellular fish skin is used for tissue repair and during manufacturing subjected to gentle processing compared to biologic materials derived from mammals. This is due to the absence of viral and prion disease transmission risk, preserving natural structure and composition of the fish skin graft. The aim of this study was to assess properties of acellular fish skin relevant for severe battlefield injuries and to compare those properties with those of dehydrated human amnion/chorion membrane. We evaluated cell ingrowth capabilities of the biological materials with microscopy techniques. Bacterial barrier properties were tested with a 2-chamber model. The microstructure of the acellular fish skin is highly porous, whereas the microstructure of dehydrated human amnion/chorion membrane is mostly nonporous. The fish skin grafts show superior ability to support 3-dimensional ingrowth of cells compared to dehydrated human amnion/chorion membrane (p fish skin is a bacterial barrier for 24 to 48 hours. The unique biomechanical properties of the acellular fish skin graft make it ideal to be used as a conformal cover for severe trauma and burn wounds in the battlefield. Reprint & Copyright © 2017 Association of Military Surgeons of the U.S.

In vitro activation of the neuro-transduction mechanism in sensitive organotypic human skin model.

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Martorina, Francesca; Casale, Costantino; Urciuolo, Francesco; Netti, Paolo A; Imparato, Giorgia

2017-01-01

Recent advances in tissue engineering have encouraged researchers to endeavor the production of fully functional three-dimensional (3D) thick human tissues in vitro. Here, we report the fabrication of a fully innervated human skin tissue in vitro that recapitulates and replicates skin sensory function. Previous attempts to innervate in vitro 3D skin models did not demonstrate an effective functionality of the nerve network. In our approach, we initially engineer functional human skin tissue based on fibroblast-generated dermis and differentiated epidermis; then, we promote rat dorsal root ganglion (DRG) neurons axon ingrowth in the de-novo developed tissue. Neurofilaments network infiltrates the entire native dermis extracellular matrix (ECM), as demonstrated by immunofluorescence and second harmonic generation (SHG) imaging. To prove sensing functionality of the tissue, we use topical applications of capsaicin, an agonist of transient receptor protein-vanilloid 1 (TRPV1) channel, and quantify calcium currents resulting from variations of Ca ++ concentration in DRG neurons innervating our model. Calcium currents generation demonstrates functional cross-talking between dermis and epidermis compartments. Moreover, through a computational fluid dynamic (CFD) analysis, we set fluid dynamic conditions for a non-planar skin equivalent growth, as proof of potential application in creating skin grafts tailored on-demand for in vivo wound shape. Copyright © 2016 Elsevier Ltd. All rights reserved.

Complete horizontal skin cell resurfacing and delayed vertical cell infiltration into porcine reconstructive tissue matrix compared to bovine collagen matrix and human dermis.

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Mirastschijski, Ursula; Kerzel, Corinna; Schnabel, Reinhild; Strauss, Sarah; Breuing, Karl-Heinz

2013-10-01

Xenogenous dermal matrices are used for hernia repair and breast reconstruction. Full-thickness skin replacement is needed after burn or degloving injuries with exposure of tendons or bones. The authors used a human skin organ culture model to study whether porcine reconstructive tissue matrix (Strattice) is effective as a dermal tissue replacement. Skin cells or split-thickness skin grafts were seeded onto human deepidermized dermis, Strattice, and Matriderm. Cellular resurfacing and matrix infiltration were monitored by live fluorescence imaging, histology, and electron microscopy. Proliferation, apoptosis, cell differentiation, and adhesion were analyzed by immunohistochemistry. Epithelial resurfacing and vertical proliferation were reduced and delayed with both bioartificial matrices compared with deepidermized dermis; however, no differences in apoptosis, cell differentiation, or basement membrane formation were found. Vertical penetration was greatest on Matriderm, whereas no matrix infiltration was found on Strattice in the first 12 days. Uncompromised horizontal resurfacing was greatest with Strattice but was absent with Matriderm. Strattice showed no stimulatory effect on cellular inflammation. Matrix texture and surface properties governed cellular performance on tissues. Although dense dermal compaction delayed vertical cellular ingrowth for Strattice, it allowed uncompromised horizontal resurfacing. Dense dermal compaction may slow matrix decomposition and result in prolonged biomechanical stability of the graft. Reconstructive surgeons should choose the adequate matrix substitute depending on biomechanical requirements at the recipient site. Strattice may be suitable as a dermal replacement at recipient sites with high mechanical load requirements.

Biocomposite nanofibrous strategies for the controlled release of biomolecules for skin tissue regeneration

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Gandhimathi C

2014-10-01

Full Text Available Chinnasamy Gandhimathi,1 Jayarama Reddy Venugopal,2 Velmurugan Bhaarathy,2 Seeram Ramakrishna,2 Srinivasan Dinesh Kumar1 1Cellular and Molecular Epigenetics Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; 2Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, Singapore Abstract: Nanotechnology and tissue engineering have enabled engineering of nanostructured strategies to meet the current challenges in skin tissue regeneration. Electrospinning technology creates porous nanofibrous scaffolds to mimic extracellular matrix of the native tissues. The present study was performed to gain some insights into the applications of poly(L-lactic acid-co-poly-(ε-caprolactone (PLACL/silk fibroin (SF/vitamin E (VE/curcumin (Cur nanofibrous scaffolds and to assess their potential for being used as substrates for the culture of human dermal fibroblasts for skin tissue engineering. PLACL/SF/VE/Cur nanofibrous scaffolds were fabricated by electrospinning and characterized by fiber morphology, membrane porosity, wettability, mechanical strength, and chemical properties by Fourier transform infrared (FTIR analysis. Human dermal fibroblasts were cultured on these scaffolds, and the cell scaffold interactions were analyzed by cell proliferation, cell morphology, secretion of collagen, expression of F-actin, and 5-chloromethylfluorescein diacetate (CMFDA dye. The electrospun nanofiber diameter was obtained between 198±4 nm and 332±13 nm for PLACL, PLACL/SF, PLACL/SF/VE, and PLACL/SF/VE/Cur nanofibrous scaffolds. FTIR analysis showed the presence of the amide groups I, II, and III, and a porosity of up to 92% obtained on these nanofibrous scaffolds. The results showed that the fibroblast proliferation, cell morphology, F-actin, CMFDA dye expression, and secretion of collagen were significantly increased in PLACL/SF/VE/Cur when compared

A role for human mitochondrial complex II in the production of reactive oxygen species in human skin

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Alasdair Anderson

2014-01-01

Full Text Available The mitochondrial respiratory chain is a major generator of cellular oxidative stress, thought to be an underlying cause of the carcinogenic and ageing process in many tissues including skin. Previous studies of the relative contributions of the respiratory chain (RC complexes I, II and III towards production of reactive oxygen species (ROS have focussed on rat tissues and certainly not on human skin which is surprising as this tissue is regularly exposed to UVA in sunlight, a potent generator of cellular oxidative stress. In a novel approach we have used an array of established specific metabolic inhibitors and DHR123 fluorescence to study the relative roles of the mitochondrial RC complexes in cellular ROS production in 2 types of human skin cells. These include additional enhancement of ROS production by exposure to physiological levels of UVA. The effects within epidermal and dermal derived skin cells are compared to other tissue cell types as well as those harbouring a compromised mitochondrial status (Rho-zero A549. The results show that the complex II inhibitor, TTFA, was the only RC inhibitor to significantly increase UVA-induced ROS production in both skin cell types (P<0.05 suggesting that the role of human skin complex II in terms of influencing ROS production is more important than previously thought particularly in comparison to liver cells. Interestingly, two-fold greater maximal activity of complex II enzyme was observed in both skin cell types compared to liver (P<0.001. The activities of RC enzymes appear to decrease with increasing age and telomere length is correlated with ageing. Our study showed that the level of maximal complex II activity was higher in the MRC5/hTERT (human lung fibroblasts transfected with telomerase cells than the corresponding wild type cells (P=0.0012 which can be considered (in terms of telomerase activity as models of younger and older cells respectively.

Mechanical Stretching Promotes Skin Tissue Regeneration via Enhancing Mesenchymal Stem Cell Homing and Transdifferentiation.

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Liang, Xiao; Huang, Xiaolu; Zhou, Yiwen; Jin, Rui; Li, Qingfeng

2016-07-01

Skin tissue expansion is a clinical procedure for skin regeneration to reconstruct cutaneous defects that can be accompanied by severe complications. The transplantation of mesenchymal stem cells (MSCs) has been proven effective in promoting skin expansion and helping to ameliorate complications; however, systematic understanding of its mechanism remains unclear. MSCs from luciferase-Tg Lewis rats were intravenously transplanted into a rat tissue expansion model to identify homing and transdifferentiation. To clarify underlying mechanisms, a systematic approach was used to identify the differentially expressed genes between mechanically stretched human MSCs and controls. The biological significance of these changes was analyzed through bioinformatic methods. We further investigated genes and pathways of interest to disclose their potential role in mechanical stretching-induced skin regeneration. Cross sections of skin samples from the expanded group showed significantly more luciferase(+) and stromal cell-derived factor 1α (SDF-1α)(+), luciferase(+)keratin 14(+), and luciferase(+)CD31(+) cells than the control group, indicating MSC transdifferentiation into epidermal basal cells and endothelial cells after SDF-1α-mediated homing. Microarray analysis suggested upregulation of genes related to hypoxia, vascularization, and cell proliferation in the stretched human MSCs. Further investigation showed that the homing of MSCs was blocked by short interfering RNA targeted against matrix metalloproteinase 2, and that mechanical stretching-induced vascular endothelial growth factor A upregulation was related to the Janus kinase/signal transducer and activator of transcription (Jak-STAT) and Wnt signaling pathways. This study determines that mechanical stretching might promote skin regeneration by upregulating MSC expression of genes related to hypoxia, vascularization, and cell proliferation; enhancing transplanted MSC homing to the expanded skin; and

Use of autologous tissue engineered skin to treat porcine full-thickness skin defects

Institute of Scientific and Technical Information of China (English)

CAI Xia; CAO Yi-lin; CUI Lei; LIU Wei; GUAN Wen-xiang

2005-01-01

Objective: To explore a feasible method to repair full-thickness skin defects utilizing tissue engineered techniques. Methods: The Changfeng hybrid swines were used and the skin specimens were cut from the posterior limb girdle region, from which the keratinocytes and fibroblasts were isolated and harvested by trypsin, EDTA, and type II collagenase. The cells were seeded in Petri dishes for primary culture. When the cells were in logarithmic growth phase, they were treated with trypsin to separate them from the floor of the tissue culture dishes. A biodegradable material, Pluronic F-127, was prefabricated and mixed with these cells, and then the cell-Pluronic compounds were seeded evenly into a polyglycolic acid (PGA). Then the constructs were replanted to the autologous animals to repair the full-thickness skin defects. Histology and immunohistochemistry of the neotissue were observed in 1, 2, 4, and 8 postoperative weeks. Results: The cell-Pluronic F-127-PGA compounds repaired autologous full-thickness skin defects 1 week after implantation. Histologically, the tissue engineered skin was similar to the normal skin with stratified epidermis overlying a moderately thick collageneous dermis. Three of the structural proteins in the epidermal basement membrane zone, type IV collagen, laminin, and type VII collagen were detected using immunohistochemical methods. Conclusions: By studying the histology and immunohistochemistry of the neotissue, the bioengineered skin graft holds great promise for improving healing of the skin defects.

Percutaneous penetration of 2-phenoxyethanol through rat and human skin.

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Roper, C S; Howes, D; Blain, P G; Williams, F M

1997-01-01

2-Phenoxyethanol applied in methanol was absorbed (64 +/- 4.4% at 24 hr) through unoccluded rat skin in vitro in the static diffusion cell with ethanol/water as receptor fluid. By comparison (43 +/- 3.7% in 24 hr) was absorbed in the flow-through diffusion system with tissue culture medium as receptor fluid. 2-Phenoxyethanol applied in methanol was absorbed (59.3 +/- 7.0% at 6 hr) through unoccluded human skin in vitro in the flow-through diffusion cell with tissue culture medium. With both unoccluded cells, 2-phenoxyethanol was lost by evaporation but occlusion of the static cell reduced evaporation and increased total absorption to 98.8 +/- 7.0%. Skin, post mitochondrial fraction, metabolized phenoxyethanol to phenoxyacetic acid at 5% of the rate for liver. Metabolism was inhibited by 1 mM pyrazole, suggesting involvement of alcohol dehydrogenase. However, first-pass metabolism of phenoxyethanol to phenoxyacetic acid was not detected during percutaneous penetration through viable rat skin in the flow-through system. First-pass metabolism in the skin does not therefore have an influence on systemic availability of dermally absorbed phenoxyethanol. These measures of phenoxyethanol absorption through rat and human skin in vitro agree well with those obtained previously in vivo.

Tissue-engineered skin preserving the potential of epithelial cells to differentiate into hair after grafting.

Science.gov (United States)

Larouche, Danielle; Cuffley, Kristine; Paquet, Claudie; Germain, Lucie

2011-03-01

The aim of this study was to evaluate whether tissue-engineered skin produced in vitro was able to sustain growth of hair follicles in vitro and after grafting. Different tissues were designed. Dissociated newborn mouse keratinocytes or newborn mouse hair buds (HBs) were added onto dermal constructs consisting of a tissue-engineered cell-derived matrix elaborated from either newborn mouse or adult human fibroblasts cultured with ascorbic acid. After 7-21 days of maturation at the air-liquid interface, no hair was noticed in vitro. Epidermal differentiation was observed in all tissue-engineered skin. However, human fibroblast-derived tissue-engineered dermis (hD) promoted a thicker epidermis than mouse fibroblast-derived tissue-engineered dermis (mD). In association with mD, HBs developed epithelial cyst-like inclusions presenting outer root sheath-like attributes. In contrast, epidermoid cyst-like inclusions lined by a stratified squamous epithelium were present in tissues composed of HBs and hD. After grafting, pilo-sebaceous units formed and hair grew in skin elaborated from HBs cultured 10-26 days submerged in culture medium in association with mD. However, the number of normal hair follicles decreased with longer culture time. This hair-forming capacity after grafting was not observed in tissues composed of hD overlaid with HBs. These results demonstrate that epithelial stem cells can be kept in vitro in a permissive tissue-engineered dermal environment without losing their potential to induce hair growth after grafting.

Generation of Genetically Modified Organotypic Skin Cultures Using Devitalized Human Dermis.

Science.gov (United States)

Li, Jingting; Sen, George L

2015-12-14

Organotypic cultures allow the reconstitution of a 3D environment critical for cell-cell contact and cell-matrix interactions which mimics the function and physiology of their in vivo tissue counterparts. This is exemplified by organotypic skin cultures which faithfully recapitulates the epidermal differentiation and stratification program. Primary human epidermal keratinocytes are genetically manipulable through retroviruses where genes can be easily overexpressed or knocked down. These genetically modified keratinocytes can then be used to regenerate human epidermis in organotypic skin cultures providing a powerful model to study genetic pathways impacting epidermal growth, differentiation, and disease progression. The protocols presented here describe methods to prepare devitalized human dermis as well as to genetically manipulate primary human keratinocytes in order to generate organotypic skin cultures. Regenerated human skin can be used in downstream applications such as gene expression profiling, immunostaining, and chromatin immunoprecipitations followed by high throughput sequencing. Thus, generation of these genetically modified organotypic skin cultures will allow the determination of genes that are critical for maintaining skin homeostasis.

The safety of donor skin preserved with glycerol - Evaluating the Euro Skin Bank preservation procedures of human donor skin against the prEN 12442 standard

NARCIS (Netherlands)

Geertsma RE; Wassenaar C; LGM

2000-01-01

The procedures for preservation of human donor skin with glycerol, as applied by the Euro Skin Bank (ESB), were evaluated against the prEN 12442 standard: animal tissues and their derivatives used in the manufacture of medical devices. The focus chosen for this review is on risks related to the

Exosomes derived from human umbilical cord blood mesenchymal stem cells stimulates rejuvenation of human skin.

Science.gov (United States)

Kim, Yoon-Jin; Yoo, Sae Mi; Park, Hwan Hee; Lim, Hye Jin; Kim, Yu-Lee; Lee, Seunghee; Seo, Kwang-Won; Kang, Kyung-Sun

2017-11-18

Human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) play an important role in cutaneous wound healing, and recent studies suggested that MSC-derived exosomes activate several signaling pathways, which are conducive in wound healing and cell growth. In this study, we investigated the roles of exosomes that are derived from USC-CM (USC-CM Exos) in cutaneous collagen synthesis and permeation. We found that USC-CM has various growth factors associated with skin rejuvenation. Our in vitro results showed that USC-CM Exos integrate in Human Dermal Fibroblasts (HDFs) and consequently promote cell migration and collagen synthesis of HDFs. Moreover, we evaluated skin permeation of USC-CM Exos by using human skin tissues. Results showed that Exo-Green labeled USC-CM Exos approached the outermost layer of the epidermis after 3 h and gradually approached the epidermis after 18 h. Moreover, increased expressions of Collagen I and Elastin were found after 3 days of treatment on human skin. The results showed that USC-CM Exos is absorbed into human skin, it promotes Collagen I and Elastin synthesis in the skin, which are essential to skin rejuvenation and shows the potential of USC-CM integration with the cosmetics or therapeutics. Copyright © 2017 Elsevier Inc. All rights reserved.

Resident CD141 (BDCA3)+ dendritic cells in human skin produce IL-10 and induce regulatory T cells that suppress skin inflammation.

Science.gov (United States)

Chu, Chung-Ching; Ali, Niwa; Karagiannis, Panagiotis; Di Meglio, Paola; Skowera, Ania; Napolitano, Luca; Barinaga, Guillermo; Grys, Katarzyna; Sharif-Paghaleh, Ehsan; Karagiannis, Sophia N; Peakman, Mark; Lombardi, Giovanna; Nestle, Frank O

2012-05-07

Human skin immune homeostasis, and its regulation by specialized subsets of tissue-residing immune sentinels, is poorly understood. In this study, we identify an immunoregulatory tissue-resident dendritic cell (DC) in the dermis of human skin that is characterized by surface expression of CD141, CD14, and constitutive IL-10 secretion (CD141(+) DDCs). CD141(+) DDCs possess lymph node migratory capacity, induce T cell hyporesponsiveness, cross-present self-antigens to autoreactive T cells, and induce potent regulatory T cells that inhibit skin inflammation. Vitamin D(3) (VitD3) promotes certain phenotypic and functional properties of tissue-resident CD141(+) DDCs from human blood DCs. These CD141(+) DDC-like cells can be generated in vitro and, once transferred in vivo, have the capacity to inhibit xeno-graft versus host disease and tumor alloimmunity. These findings suggest that CD141(+) DDCs play an essential role in the maintenance of skin homeostasis and in the regulation of both systemic and tumor alloimmunity. Finally, VitD3-induced CD141(+) DDC-like cells have potential clinical use for their capacity to induce immune tolerance.

Tissue distribution and subcellular localizations determine in vivo functional relationship among prostasin, matriptase, HAI-1, and HAI-2 in human skin.

Science.gov (United States)

Lee, Shiao-Pieng; Kao, Chen-Yu; Chang, Shun-Cheng; Chiu, Yi-Lin; Chen, Yen-Ju; Chen, Ming-Hsing G; Chang, Chun-Chia; Lin, Yu-Wen; Chiang, Chien-Ping; Wang, Jehng-Kang; Lin, Chen-Yong; Johnson, Michael D

2018-01-01

The membrane-bound serine proteases prostasin and matriptase and the Kunitz-type protease inhibitors HAI-1 and HAI-2 are all expressed in human skin and may form a tightly regulated proteolysis network, contributing to skin pathophysiology. Evidence from other systems, however, suggests that the relationship between matriptase and prostasin and between the proteases and the inhibitors can be context-dependent. In this study the in vivo zymogen activation and protease inhibition status of matriptase and prostasin were investigated in the human skin. Immunohistochemistry detected high levels of activated prostasin in the granular layer, but only low levels of activated matriptase restricted to the basal layer. Immunoblot analysis of foreskin lysates confirmed this in vivo zymogen activation status and further revealed that HAI-1 but not HAI-2 is the prominent inhibitor for prostasin and matriptase in skin. The zymogen activation status and location of the proteases does not support a close functional relation between matriptase and prostasin in the human skin. The limited role for HAI-2 in the inhibition of matriptase and prostasin is the result of its primarily intracellular localization in basal and spinous layer keratinocytes, which probably prevents the Kunitz inhibitor from interacting with active prostasin or matriptase. In contrast, the cell surface expression of HAI-1 in all viable epidermal layers renders it an effective regulator for matriptase and prostasin. Collectively, our study suggests the importance of tissue distribution and subcellular localization in the functional relationship between proteases and protease inhibitors.

Experimental Human Cell and Tissue Models of Pemphigus

Science.gov (United States)

van der Wier, Gerda; Pas, Hendri H.; Jonkman, Marcel F.

2010-01-01

Pemphigus is a chronic mucocutaneous autoimmune bullous disease that is characterized by loss of cell-cell contact in skin and/or mucous membranes. Past research has successfully identified desmosomes as immunological targets and has demonstrated that acantholysis is initiated through direct binding of IgG. The exact mechanisms of acantholysis, however, are still missing. Experimental model systems have contributed considerably to today's knowledge and are still a favourite tool of research. In this paper we will describe to what extent human cell and tissue models represent the in vivo situation, for example, organ cultures of human skin, keratinocyte cultures, and human skin grafted on mice and, furthermore, how suitable they are to study the pathogenesis of pemphigus. Organ cultures closely mimic the architecture of the epidermis but are less suitable to answer posed biochemical questions. Cultured keratinocyte monolayers are convenient in this respect, but their desmosomal make-up in terms of adhesion molecules does not exactly reflect the in vivo situation. Reconstituted skin is a relatively new model that approaches organ culture. In models of human skin grafted on mice, acantholysis can be studied in actual human skin but now with all the advantages of an animal model. PMID:20585596

Measurement of DNA biomarkers for the safety of tissue-engineered medical products, using artificial skin as a model.

Science.gov (United States)

Rodriguez, Henry; O'Connell, Catherine; Barker, Peter E; Atha, Donald H; Jaruga, Pawel; Birincioglu, Mustafa; Marino, Michael; McAndrew, Patricia; Dizdaroglu, Miral

2004-01-01

To test the hypothesis that the process of tissue engineering introduces genetic damage to tissue-engineered medical products, we employed the use of five state-of-the-art measurement technologies to measure a series of DNA biomarkers in commercially available tissue-engineered skin as a model. DNA was extracted from the skin and compared with DNA from cultured human neonatal control cells (dermal fibroblasts and epidermal keratinocytes) and adult human fibroblasts from a 55-year-old donor and a 96-year-old donor. To determine whether tissue engineering caused oxidative DNA damage, gas chromatography/isotope-dilution mass spectrometry and liquid chromatography/isotope-dilution mass spectrometry were used to measure six oxidatively modified DNA bases as biomarkers. Normal endogenous levels of the modified DNA biomarkers were not elevated in tissue-engineered skin when compared with control cells. Next, denaturing high-performance liquid chromatography and capillary electrophoresis-single strand conformation polymorphism were used to measure genetic mutations. Specifically, the TP53 tumor suppressor gene was screened for mutations, because it is the most commonly mutated gene in skin cancer. The tissue-engineered skin was found to be free of TP53 mutations at the level of sensitivity of these measurement technologies. Lastly, fluorescence in situ hybridization was employed to measure the loss of Y chromosome, which is associated with excessive cell passage and aging. Loss of Y chromosome was not detected in the tissue-engineered skin and cultured neonatal cells used as controls. In this study, we have demonstrated that tissue engineering (for TestSkin II) does not introduce genetic damage above the limits of detection of the state-of-the-art technologies used. This work explores the standard for measuring genetic damage that could be introduced during production of novel tissue-engineered products. More importantly, this exploratory work addresses technological

Xenobiotic metabolism in human skin and 3D human skin reconstructs: A review

NARCIS (Netherlands)

Gibbs, S.; Sandt, J.J.M. van de; Merk, H.F.; Lockley, D.J.; Pendlington, R.U.; Pease, C.K.

2007-01-01

In this review, we discuss and compare studies of xenobiotic metabolism in both human skin and 3D human skin reconstructs. In comparison to the liver, the skin is a less studied organ in terms of characterising metabolic capability. While the skin forms the major protective barrier to environmental

In Vitro Evaluation of a Biomedical-Grade Bilayer Chitosan Porous Skin Regenerating Template as a Potential Dermal Scaffold in Skin Tissue Engineering

Directory of Open Access Journals (Sweden)

Chin Keong Lim

2011-01-01

Full Text Available Chitosan is a copolymer of N-acetylglucosamine and glucosamine. A bilayer chitosan porous skin regenerating template (CPSRT has been developed for skin tissue engineering. The pore size of the CPSRT was assessed using a scanning electron microscopy (SEM. The in vitro cytocompatibility of the CPSRT was tested on primary human epidermal keratinocyte (pHEK cultures by measuring lactate dehydrogenase (LDH levels and skin irritation by western blot analysis of the interleukin-8 (IL-8 and tumor necrosis factor-α (TNF-α secretions. The ability of the CPSRT to support cell ingrowth was evaluated by seeding primary human dermal fibroblasts (pHDFs on the scaffold, staining the cells with live/dead stain, and imaging the construct by confocal microscopy (CLSM. The CPSRT with pore sizes ranging from 50 to 150 μm was cytocompatible because it did not provoke the additional production of IL-8 and TNF-α by pHEK cultures. Cultured pHDFs were able to penetrate the CPSRT and had increased in number on day 14. In conclusion, the CPSRT serves as an ideal template for skin tissue engineering.

Qualitative and semi quantitative analysis in the healing area of athymic nude mice skin engrafted with human skin sterilized with gamma radiation

International Nuclear Information System (INIS)

Miranda, Jurandir Tomaz de; Bringel, Fabiana; Alves, Nelson Mendes; Antebi, Uri; Funari, Ana Paula; Mathor, Monica B.

2015-01-01

In recent decades there has been a great interest in the radio-sterilized grafts for human skin grafts. This tissue is taken from a cadaver or multi-organ donor and samples are processed and stored in glycerol at concentrations above 85%. Although this procedure is carried out under aseptic conditions, after the final packaging one can sterilize the tissues with ionizing radiation in order to increase the safety level of sterility. The purpose of this study was to evaluate the behavior of the healing repair process that occurs between the graft and the skin of athymic NUDE mice. The samples of human skin treated with glycerol were divided into three groups: the control group 1 (non-irradiated), irradiated group 2 at 25 kGy and irradiated group 3, at 50 kGy. These tissues were grafted onto athymic NUDE mice which were sacrificed after 3, 7 and 21 days. After the sacrifice, part of the back fur of the animals containing human skin graft was removed with hematoxylin and eosin (H/E). The histological sections were analyzed for the integrity of tissue, presence and location of keratinocytes, fibroblasts, defense cells and blood vessels. Thus it was examined whether over time the graft was incorporated into the body or if there was a process of healing by secondary intention. (author)

Qualitative and semi quantitative analysis in the healing area of athymic nude mice skin engrafted with human skin sterilized with gamma radiation

Energy Technology Data Exchange (ETDEWEB)

Miranda, Jurandir Tomaz de; Bringel, Fabiana; Alves, Nelson Mendes; Antebi, Uri; Funari, Ana Paula; Mathor, Monica B., E-mail: tomaz_ju@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

In recent decades there has been a great interest in the radio-sterilized grafts for human skin grafts. This tissue is taken from a cadaver or multi-organ donor and samples are processed and stored in glycerol at concentrations above 85%. Although this procedure is carried out under aseptic conditions, after the final packaging one can sterilize the tissues with ionizing radiation in order to increase the safety level of sterility. The purpose of this study was to evaluate the behavior of the healing repair process that occurs between the graft and the skin of athymic NUDE mice. The samples of human skin treated with glycerol were divided into three groups: the control group 1 (non-irradiated), irradiated group 2 at 25 kGy and irradiated group 3, at 50 kGy. These tissues were grafted onto athymic NUDE mice which were sacrificed after 3, 7 and 21 days. After the sacrifice, part of the back fur of the animals containing human skin graft was removed with hematoxylin and eosin (H/E). The histological sections were analyzed for the integrity of tissue, presence and location of keratinocytes, fibroblasts, defense cells and blood vessels. Thus it was examined whether over time the graft was incorporated into the body or if there was a process of healing by secondary intention. (author)

Skin Diseases: Cross-section of human skin

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Skip Navigation Bar Home Current Issue Past Issues Skin Diseases Cross-section of human skin Past Issues / Fall 2008 Table of Contents For ... Logical Images, Inc. I n the areas of skin health and skin diseases, the NIH's National Institute ...

Fabrication of Chitin/Poly(butylene succinate/Chondroitin Sulfate Nanoparticles Ternary Composite Hydrogel Scaffold for Skin Tissue Engineering

Directory of Open Access Journals (Sweden)

S. Deepthi

2014-12-01

Full Text Available Skin loss is one of the oldest and still not totally resolved problems in the medical field. Since spontaneous healing of the dermal defects would not occur, the regeneration of full thickness of skin requires skin substitutes. Tissue engineering constructs would provide a three dimensional matrix for the reconstruction of skin tissue and the repair of damage. The aim of the present work is to develop a chitin based scaffold, by blending it with poly(butylene succinate (PBS, an aliphatic, biodegradable and biocompatible synthetic polymer with excellent mechanical properties. The presence of chondroitin sulfate nanoparticles (CSnp in the scaffold would favor cell adhesion. A chitin/PBS/CSnp composite hydrogel scaffold was developed and characterized by SEM (Scanning Electron Microscope, FTIR (Fourier Transform Infrared Spectroscopy, and swelling ratio of scaffolds were analyzed. The scaffolds were evaluated for the suitability for skin tissue engineering application by cytotoxicity, cell attachment, and cell proliferation studies using human dermal fibroblasts (HDF. The cytotoxicity and cell proliferation studies using HDF confirm the suitability of the scaffold for skin regeneration. In short, these results show promising applicability of the developed chitin/PBS/CSnps ternary composite hydrogel scaffolds for skin tissue regeneration.

Deep tissue injury in development of pressure ulcers: a decrease of inflammasome activation and changes in human skin morphology in response to aging and mechanical load.

Directory of Open Access Journals (Sweden)

Olivera Stojadinovic

Full Text Available Molecular mechanisms leading to pressure ulcer development are scarce in spite of high mortality of patients. Development of pressure ulcers that is initially observed as deep tissue injury is multifactorial. We postulate that biomechanical forces and inflammasome activation, together with ischemia and aging, may play a role in pressure ulcer development. To test this we used a newly-developed bio-mechanical model in which ischemic young and aged human skin was subjected to a constant physiological compressive stress (load of 300 kPa (determined by pressure plate analyses of a person in a reclining position for 0.5-4 hours. Collagen orientation was assessed using polarized light, whereas inflammasome proteins were quantified by immunoblotting. Loaded skin showed marked changes in morphology and NLRP3 inflammasome protein expression. Sub-epidermal separations and altered orientation of collagen fibers were observed in aged skin at earlier time points. Aged skin showed significant decreases in the levels of NLRP3 inflammasome proteins. Loading did not alter NLRP3 inflammasome proteins expression in aged skin, whereas it significantly increased their levels in young skin. We conclude that aging contributes to rapid morphological changes and decrease in inflammasome proteins in response to tissue damage, suggesting that a decline in the innate inflammatory response in elderly skin could contribute to pressure ulcer pathogenesis. Observed morphological changes suggest that tissue damage upon loading may not be entirely preventable. Furthermore, newly developed model described here may be very useful in understanding the mechanisms of deep tissue injury that may lead towards development of pressure ulcers.

Skin-associated lymphoid tissues (SALT): origins and functions

International Nuclear Information System (INIS)

Streilein, J.W.

1983-01-01

The skin has an unusual set of immunologic requirements. It is confronted by a specialized set of pathogenic organisms and environmental chemicals that represent a distinctive spectrum of antigenic specificities. Skin is subjected to physicochemical stresses such as irradiation with ultraviolet light that alter dramatically its immunologic properties. It is proposed that nature has provided skin with a unique collection of lymphoid cells, reticular cells, and organized lymphoid organs to deal with these special demands. Evidence in favor of the existence of skin-associated lymphoid tissues (SALT) includes (1) the cutaneous microenvironment is capable on its own of accepting, processing, and presenting nominal antigen; (2) strategically located peripheral lymph nodes are able to accept immunogenic signals derived from skin; (3) subsets of T lymphocytes display differential affinity for skin and its associated peripheral nodes; and (4) acquisition of this affinity by T cells is determined at least in part by differentiation signals received in situ from resident cutaneous cells. Responsibility for the establishment and integration of SALT rests with keratinocytes, Langerhans cells, and immunocompetent lymphocytes, each of which contributes uniquely to the synthesis. Together they provide skin with immune surveillance that effectively prejudices against the development of cutaneous neoplasms and persistent infection with intracellular pathogens. In patients who have been under long-term immunosuppressive therapy, the large majority of nonlymphoid malignancies arise within the skin, rather than other types of tissues. These data suggest that immune surveillance, once thought to be an immune defense operative in all somatic tissues, is a specialized immune function dedicated to the skin and mediated by SALT

Skin Diseases Modeling using Combined Tissue Engineering and Microfluidic Technologies.

Science.gov (United States)

Mohammadi, Mohammad Hossein; Heidary Araghi, Behnaz; Beydaghi, Vahid; Geraili, Armin; Moradi, Farshid; Jafari, Parya; Janmaleki, Mohsen; Valente, Karolina Papera; Akbari, Mohsen; Sanati-Nezhad, Amir

2016-10-01

In recent years, both tissue engineering and microfluidics have significantly contributed in engineering of in vitro skin substitutes to test the penetration of chemicals or to replace damaged skins. Organ-on-chip platforms have been recently inspired by the integration of microfluidics and biomaterials in order to develop physiologically relevant disease models. However, the application of organ-on-chip on the development of skin disease models is still limited and needs to be further developed. The impact of tissue engineering, biomaterials and microfluidic platforms on the development of skin grafts and biomimetic in vitro skin models is reviewed. The integration of tissue engineering and microfluidics for the development of biomimetic skin-on-chip platforms is further discussed, not only to improve the performance of present skin models, but also for the development of novel skin disease platforms for drug screening processes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vivo analysis of tissue by Raman microprobe: examination of human skin lesions and esophagus Barrett's mucosa on an animal model

Science.gov (United States)

Tfayli, Ali; Piot, Olivier; Derancourt, Sylvie; Cadiot, Guillaume; Diebold, Marie D.; Bernard, Philippe; Manfait, Michel

2006-02-01

In the last few years, Raman spectroscopy has been increasingly used for the characterization of normal and pathological tissues. A new Raman system, constituted of optic fibers bundle coupled to an axial Raman spectrometer (Horiba Jobin Yvon SAS), was developed for in vivo investigations. Here, we present in vivo analysis on two tissues: human skin and esophagus mucosa on a rat model. The skin is a directly accessible organ, representing a high diversity of lesions and cancers. Including malignant melanoma, basal cell carcinoma and the squamous cell carcinoma, skin cancer is the cancer with the highest incidence worldwide. Several Raman investigations were performed to discriminate and classify different types of skin lesions, on thin sections of biopsies. Here, we try to characterize in vivo the different types of skin cancers in order to be able to detect them in their early stages of development and to define precisely the exeresis limits. Barrett's mucosa was also studied by in vivo examination of rat's esophagus. Barrett's mucosa, induced by gastro-esophageal reflux, is a pretumoral state that has to be carefully monitored due to its high risk of evolution in adenocarcinoma. A better knowledge of the histological transformation of esophagus epithelium in a Barrett's type will lead to a more efficient detection of the pathology for its early diagnosis. To study these changes, an animal model (rats developing Barrett's mucosa after duodenum - esophagus anastomosis) was used. Potential of vibrational spectroscopy for Barrett's mucosa identification is assessed on this model.

Direct 3D cell-printing of human skin with functional transwell system.

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Kim, Byoung Soo; Lee, Jung-Seob; Gao, Ge; Cho, Dong-Woo

2017-06-06

Three-dimensional (3D) cell-printing has been emerging as a promising technology with which to build up human skin models by enabling rapid and versatile design. Despite the technological advances, challenges remain in the development of fully functional models that recapitulate complexities in the native tissue. Moreover, although several approaches have been explored for the development of biomimetic human skin models, the present skin models based on multistep fabrication methods using polydimethylsiloxane chips and commercial transwell inserts could be tackled by leveraging 3D cell-printing technology. In this paper, we present a new 3D cell-printing strategy for engineering a 3D human skin model with a functional transwell system in a single-step process. A hybrid 3D cell-printing system was developed, allowing for the use of extrusion and inkjet modules at the same time. We began by revealing the significance of each module in engineering human skin models; by using the extrusion-dispensing module, we engineered a collagen-based construct with polycaprolactone (PCL) mesh that prevented the contraction of collagen during tissue maturation; the inkjet-based dispensing module was used to uniformly distribute keratinocytes. Taking these features together, we engineered a human skin model with a functional transwell system; the transwell system and fibroblast-populated dermis were consecutively fabricated by using the extrusion modules. Following this process, keratinocytes were uniformly distributed onto the engineered dermis by the inkjet module. Our transwell system indicates a supportive 3D construct composed of PCL, enabling the maturation of a skin model without the aid of commercial transwell inserts. This skin model revealed favorable biological characteristics that included a stabilized fibroblast-stretched dermis and stratified epidermis layers after 14 days. It was also observed that a 50 times reduction in cost was achieved and 10 times less medium was

In vivo transformation of human skin with human papillomavirus type 11 from condylomatot acuminata

International Nuclear Information System (INIS)

Kreider, J.W.; Howett, M.K.; Lill, N.L.; Bartlett, G.L.; Zaino, R.J.; Sedlacek, T.V.; Mortel, R.

1986-01-01

Human papillomaviruses (HPVs) have been implicated in the development of a number of human malignancies, but direct tests of their involvement have not been possible. The authors describe a system in which human skin from various skin from various sites was infected with HPV type 11 (HPV-11) extracted from vulvar condylomata and was grafted beneath the renal capsule of athymic mice. Most of the skin grafts so treated underwent morphological transformation, resulting in the development of condylomata identical to those which occur spontaneously in patients. Foreskins responded with the most vigorous proliferative response to HPV-11. The lesions produced the characteristic intranuclear group-specific antigen of papillomaviruses. Both dot blot and Southern blot analysis of DNA from the lesions revealed the presence of HPV-11 DNA in the transformed grafts. These results demonstrate the first laboratory system for the study of the interaction of human skin with an HPV. The method may be useful in understanding the mechanisms of HPV transformation and replication and is free of the ethical restraints which have impeded study. This system will allow the direct study of factors which permit neoplastic progression of HPV-induced cutaneous lesions in human tissues

Novel wearable-type biometric devices based on skin tissue optics with multispectral LED-photodiode matrix

Science.gov (United States)

Jo, Young Chang; Kim, Hae Na; Kang, Jae Hwan; Hong, Hyuck Ki; Choi, Yeon Shik; Jung, Suk Won; Kim, Sung Phil

2017-04-01

In this study, we examined the possibility of using a multispectral skin photomatrix (MSP) module as a novel biometric device. The MSP device measures optical patterns of the wrist skin tissue. Optical patterns consist of 2 × 8 photocurrent intensities of photodiode arrays, which are generated by optical transmission and diffuse reflection of photons from LED light sources with variable wavelengths into the wrist skin tissue. Optical patterns detected by the MSP device provide information on both the surface and subsurface characteristics of the human skin tissue. We found that in the 21 subjects we studied, they showed their unique characteristics, as determined using several wavelengths of light. The experimental results show that the best personal identification accuracy can be acquired using a combination of infrared light and yellow light. This novel biometric device, the MSP module, exhibited an excellent false acceptance rate (FAR) of 0.3% and a false rejection rate (FRR) of 0.0%, which are better than those of commercialized biometric devices such as a fingerprint biometric system. From these experimental results, we found that people exhibit unique optical patterns of their inner-wrist skin tissue and this uniqueness could be used for developing novel high-accuracy personal identification devices.

Reflectance spectrometry of normal and bruised human skins: experiments and modeling

International Nuclear Information System (INIS)

Kim, Oleg; Alber, Mark; McMurdy, John; Lines, Collin; Crawford, Gregory; Duffy, Susan

2012-01-01

A stochastic photon transport model in multilayer skin tissue combined with reflectance spectroscopy measurements is used to study normal and bruised skins. The model is shown to provide a very good approximation to both normal and bruised real skin tissues by comparing experimental and simulated reflectance spectra. The sensitivity analysis of the skin reflectance spectrum to variations of skin layer thicknesses, blood oxygenation parameter and concentrations of main chromophores is performed to optimize model parameters. The reflectance spectrum of a developed bruise in a healthy adult is simulated, and the concentrations of bilirubin, blood volume fraction and blood oxygenation parameter are determined for different times as the bruise progresses. It is shown that bilirubin and blood volume fraction reach their peak values at 80 and 55 h after contusion, respectively, and the oxygenation parameter is lower than its normal value during 80 h after contusion occurred. The obtained time correlations of chromophore concentrations in developing contusions are shown to be consistent with previous studies. The developed model uses a detailed seven-layer skin approximation for contusion and allows one to obtain more biologically relevant results than those obtained with previous models using one- to three-layer skin approximations. A combination of modeling with spectroscopy measurements provides a new tool for detailed biomedical studies of human skin tissue and for age determination of contusions. (paper)

The Microbiota of the Human Skin.

Science.gov (United States)

Egert, Markus; Simmering, Rainer

2016-01-01

The aim of this chapter is to sum up important progress in the field of human skin microbiota research that was achieved over the last years.The human skin is one of the largest and most versatile organs of the human body. Owing to its function as a protective interface between the largely sterile interior of the human body and the highly microbially contaminated outer environment, it is densely colonized with a diverse and active microbiota. This skin microbiota is of high importance for human health and well-being. It is implicated in several severe skin diseases and plays a major role in wound infections. Many less severe, but negatively perceived cosmetic skin phenomena are linked with skin microbes, too. In addition, skin microorganisms, in particular on the human hands, are crucial for the field of hygiene research. Notably, apart from being only a potential source of disease and contamination, the skin microbiota also contributes to the protective functions of the human skin in many ways. Finally, the analysis of structure and function of the human skin microbiota is interesting from a basic, evolutionary perspective on human microbe interactions.Key questions in the field of skin microbiota research deal with (a) a deeper understanding of the structure (species inventory) and function (physiology) of the healthy human skin microbiota in space and time, (b) the distinction of resident and transient skin microbiota members, (c) the distinction of beneficial skin microorganisms from microorganisms or communities with an adverse or sickening effect on their hosts, (d) factors shaping the skin microbiota and its functional role in health and disease, (e) strategies to manipulate the skin microbiota for therapeutic reasons.

Determination of the axial and circumferential mechanical properties of the skin tissue using experimental testing and constitutive modeling.

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Karimi, Alireza; Navidbakhsh, Mahdi; Haghighatnama, Maedeh; Haghi, Afsaneh Motevalli

2015-01-01

The skin, being a multi-layered material, is responsible for protecting the human body from the mechanical, bacterial, and viral insults. The skin tissue may display different mechanical properties according to the anatomical locations of a body. However, these mechanical properties in different anatomical regions and at different loading directions (axial and circumferential) of the mice body to date have not been determined. In this study, the axial and circumferential loads were imposed on the mice skin samples. The elastic modulus and maximum stress of the skin tissues were measured before the failure occurred. The nonlinear mechanical behavior of the skin tissues was also computationally investigated through a suitable constitutive equation. Hyperelastic material model was calibrated using the experimental data. Regardless of the anatomic locations of the mice body, the results revealed significantly different mechanical properties in the axial and circumferential directions and, consequently, the mice skin tissue behaves like a pure anisotropic material. The highest elastic modulus was observed in the back skin under the circumferential direction (6.67 MPa), while the lowest one was seen in the abdomen skin under circumferential loading (0.80 MPa). The Ogden material model was narrowly captured the nonlinear mechanical response of the skin at different loading directions. The results help to understand the isotropic/anisotropic mechanical behavior of the skin tissue at different anatomical locations. They also have implications for a diversity of disciplines, i.e., dermatology, cosmetics industry, clinical decision making, and clinical intervention.

Modeling and simulation of heat distribution in human skin caused by laser irradiation

NARCIS (Netherlands)

Luan, Y.; Dams, S.D.

2009-01-01

Study of light-based skin rejuvenation needs prospective insights of mechanism of laser tissue interaction. A well-built model plays a key role in predicting temperature distribution in human skin exposed to laser irradiation. Therefore, it not only provides guidance for in vitro experiment, but

Human Epidermal Langerhans Cells Maintain Immune Homeostasis in Skin by Activating Skin Resident Regulatory T Cells

Science.gov (United States)

Seneschal, Julien; Clark, Rachael A.; Gehad, Ahmed; Baecher-Allan, Clare M.; Kupper, Thomas S.

2013-01-01

Recent discoveries indicate that the skin of a normal individual contains 10-20 billion resident memory T cells ( which include various T helper, T cytotoxic, and T regulatory subsets, that are poised to respond to environmental antigens. Using only autologous human tissues, we report that both in vitro and in vivo, resting epidermal Langerhan cells (LC) selectively and specifically induced the activation and proliferation of skin resident regulatory T cells (Treg), a minor subset of skin resident memory T cells. In the presence of foreign pathogen, however, the same LC activated and induced proliferation of effector memory T (Tem) cells and limited Treg cells activation. These underappreciated properties of LC: namely maintenance of tolerance in normal skin, and activation of protective skin resident memory T cells upon infectious challenge, help clarify the role of LC in skin. PMID:22560445

In vitro dermal absorption of pyrethroid pesticides in human and rat skin

International Nuclear Information System (INIS)

Hughes, Michael F.; Edwards, Brenda C.

2010-01-01

Dermal exposure to pyrethroid pesticides can occur during manufacture and application. This study examined the in vitro dermal absorption of pyrethroids using rat and human skin. Dermatomed skin from adult male Long Evans rats or human cadavers was mounted in flow-through diffusion cells, and radiolabeled bifenthrin, deltamethrin or cis-permethrin was applied in acetone to the skin. Fractions of receptor fluid were collected every 4 h. At 24 h, the skins were washed with soap and water to remove unabsorbed chemical. The skin was then solubilized. Two additional experiments were performed after washing the skin; the first was tape-stripping the skin and the second was the collection of receptor fluid for an additional 24 h. Receptor fluid, skin washes, tape strips and skin were analyzed for radioactivity. For rat skin, the wash removed 53-71% of the dose and 26-43% remained in the skin. The cumulative percentage of the dose at 24 h in the receptor fluid ranged from 1 to 5%. For human skin, the wash removed 71-83% of the dose and 14-25% remained in the skin. The cumulative percentage of the dose at 24 h in the receptor fluid was 1-2%. Tape-stripping removed 50-56% and 79-95% of the dose in rat and human skin, respectively, after the wash. From 24-48 h, 1-3% and about 1% of the dose diffused into the receptor fluid of rat and human skin, respectively. The pyrethroids bifenthrin, deltamethrin and cis-permethrin penetrated rat and human skin following dermal application in vitro. However, a skin wash removed 50% or more of the dose from rat and human skin. Rat skin was more permeable to the pyrethroids than human skin. Of the dose in skin, 50% or more was removed by tape-stripping, suggesting that permeation of pyrethroids into viable tissue could be impeded. The percentage of the dose absorbed into the receptor fluid was considerably less than the dose in rat and human skin. Therefore, consideration of the skin type used and fractions analyzed are important when using

Elemental composition of skin tissue by PIXE and INAA analyses

International Nuclear Information System (INIS)

Hollands, R.; Spyrou, N.M.

1997-01-01

Hypertrophic scars are a particular type of scar that can form after any type of dermal injury. They are unsightly, red, elevated above normal skin level, itchy and painful. At present no-one knows why these scars form. Due to the differences between scar tissue and normal skin it was decided to analyse skin tissue which at a later date would be compared to scar tissue. Spit skin graft (epidermis) samples as well as full thickness skin (epidermis to dermis) tissue were analysed using PIXE and RBS with a 2 MeV proton beam. The epidermis was compared to the dermis to see if there were any variations between the two. In all the samples P, S, Cl, K, Ca, Fe, and Cd were detected and in a majority of the samples Zn and Ba were found, using PIXE. It was found that, between the epidermis and dermis, there was an significant increase in P in the epidermis in both full thickness and split skin graft samples. Complementary elemental analysis was also performed using neutron activation, and Br, Na and Zn were detected. (author)

Assessment of skin barrier function and biochemical changes of ex vivo human skin in response to physical and chemical barrier disruption.

Science.gov (United States)

Döge, Nadine; Avetisyan, Araks; Hadam, Sabrina; Pfannes, Eva Katharina Barbosa; Rancan, Fiorenza; Blume-Peytavi, Ulrike; Vogt, Annika

2017-07-01

Topical dermatotherapy is intended to be used on diseased skin. Novel drug delivery systems even address differences between intact and diseased skin underlining the need for pre-clinical assessment of different states of barrier disruption. Herein, we studied how short-term incubation in culture media compared to incubation in humidified chambers affects human skin barrier function and viability. On both models we assessed different types and intensities of physical and chemical barrier disruption methods with regard to structural integrity, biophysical parameters and cytokine levels. Tissue degeneration and proliferative activity limited the use of tissue cultures to 48h. Viability is better preserved in cultured tissue. Tape-stripping (50×TS) and 4h sodium lauryl sulfate (SLS) pre-treatment were identified as highly reproducible and effective procedures for barrier disruption. Transepidermal water loss (TEWL) values reproducibly increased with the intensity of disruption while sebum content and skin surface pH were of limited value. Interleukin (IL)-6/8 and various chemokines and proteases were increased in tape-stripped skin which was more pronounced in SLS-treated skin tissue extracts. Thus, albeit limited to 48h, cultured full-thickness skin maintained several barrier characteristics and responded to different intensities of barrier disruption. Potentially, these models can be used to assess pre-clinically the efficacy and penetration of anti-inflammatory compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Future Prospects for Scaffolding Methods and Biomaterials in Skin Tissue Engineering: A Review.

Science.gov (United States)

Chaudhari, Atul A; Vig, Komal; Baganizi, Dieudonné Radé; Sahu, Rajnish; Dixit, Saurabh; Dennis, Vida; Singh, Shree Ram; Pillai, Shreekumar R

2016-11-25

Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL), and poly-ethylene-glycol (PEG), etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts.

Studies on nerve terminations in human mucosa and skin

OpenAIRE

Hilliges, Marita

1997-01-01

- In spite of their accessibility and important sensory function,the nervous tissue components of human oral and vaginal mucosa and skin have beensubject to very few, if any, systematic investigations. Studies on the innervationof oral tissues have mainly focused on the dental pulp, the periodontium and thegingiva, probably because of specific clinical interest, thus largely neglectingthe mucosa. Genital studies comprise only in a few cases the vagina and when thevagina is i...

Simulation study and guidelines to generate Laser-induced Surface Acoustic Waves for human skin feature detection

Science.gov (United States)

Li, Tingting; Fu, Xing; Chen, Kun; Dorantes-Gonzalez, Dante J.; Li, Yanning; Wu, Sen; Hu, Xiaotang

2015-12-01

Despite the seriously increasing number of people contracting skin cancer every year, limited attention has been given to the investigation of human skin tissues. To this regard, Laser-induced Surface Acoustic Wave (LSAW) technology, with its accurate, non-invasive and rapid testing characteristics, has recently shown promising results in biological and biomedical tissues. In order to improve the measurement accuracy and efficiency of detecting important features in highly opaque and soft surfaces such as human skin, this paper identifies the most important parameters of a pulse laser source, as well as provides practical guidelines to recommended proper ranges to generate Surface Acoustic Waves (SAWs) for characterization purposes. Considering that melanoma is a serious type of skin cancer, we conducted a finite element simulation-based research on the generation and propagation of surface waves in human skin containing a melanoma-like feature, determine best pulse laser parameter ranges of variation, simulation mesh size and time step, working bandwidth, and minimal size of detectable melanoma.

Elucidation of xenobiotic metabolism pathways in human skin and human skin models by proteomic profiling.

Directory of Open Access Journals (Sweden)

Sven van Eijl

Full Text Available BACKGROUND: Human skin has the capacity to metabolise foreign chemicals (xenobiotics, but knowledge of the various enzymes involved is incomplete. A broad-based unbiased proteomics approach was used to describe the profile of xenobiotic metabolising enzymes present in human skin and hence indicate principal routes of metabolism of xenobiotic compounds. Several in vitro models of human skin have been developed for the purpose of safety assessment of chemicals. The suitability of these epidermal models for studies involving biotransformation was assessed by comparing their profiles of xenobiotic metabolising enzymes with those of human skin. METHODOLOGY/PRINCIPAL FINDINGS: Label-free proteomic analysis of whole human skin (10 donors was applied and analysed using custom-built PROTSIFT software. The results showed the presence of enzymes with a capacity for the metabolism of alcohols through dehydrogenation, aldehydes through dehydrogenation and oxidation, amines through oxidation, carbonyls through reduction, epoxides and carboxylesters through hydrolysis and, of many compounds, by conjugation to glutathione. Whereas protein levels of these enzymes in skin were mostly just 4-10 fold lower than those in liver and sufficient to support metabolism, the levels of cytochrome P450 enzymes were at least 300-fold lower indicating they play no significant role. Four epidermal models of human skin had profiles very similar to one another and these overlapped substantially with that of whole skin. CONCLUSIONS/SIGNIFICANCE: The proteomics profiling approach was successful in producing a comprehensive analysis of the biotransformation characteristics of whole human skin and various in vitro skin models. The results show that skin contains a range of defined enzymes capable of metabolising different classes of chemicals. The degree of similarity of the profiles of the in vitro models indicates their suitability for epidermal toxicity testing. Overall, these

Expression of telomerase reverse transcriptase in radiation-induced chronic human skin ulcer

International Nuclear Information System (INIS)

Zhao Po; Li Zhijun; Lu Yali; Zhong Mei; Gu Qingyang; Wang Dewen

2001-01-01

Objective: To investigate the expression of the catalytic subunit of telomerase, telomerase reverse transcriptase (TRT) and the possible relationship between the TRT and cancer transformation or poor healing in radiation-induced chronic ulcer of human skin. Methods: Rabbit antibody against human TRT and SP immunohistochemical method were used to detect TRT expression in 24 cases of formalin-fixed, paraffin-embed human skin chronic ulcer tissues induced by radiation, 5 cases of normal skin, 2 of burned skin, and 8 of carcinoma. Results: The positive rate for TRT was 58.3%(14/24) in chronic radiation ulcers, of which the strongly positive rate was 41.7%(10/24) and the weakly positive 16.7%(4/24), 0% in normal (0/5) and burned skin (0/2), and 100% in carcinoma (8/8). The strongly positive expression of TRT was observed almost always in the cytoplasm and nucleus of squamous epithelial cells of proliferative epidermis but the negative and partly weakly positive expression in the smooth muscles, endothelia of small blood vessels and capillaries, and fibroblasts. Chronic inflammtory cells, plasmacytes and lymphocytes also showed weakly positive for TRT. Conclusion: TRT expression could be involved in the malignant transformation of chronic radiation ulcer into squamous carcinoma, and in the poor healing caused by sclerosis of small blood vessels and lack of granulation tissue consisting of capillaries and fibroblasts

Human skin volatiles: a review.

Science.gov (United States)

Dormont, Laurent; Bessière, Jean-Marie; Cohuet, Anna

2013-05-01

Odors emitted by human skin are of great interest to biologists in many fields; applications range from forensic studies to diagnostic tools, the design of perfumes and deodorants, and the ecology of blood-sucking insect vectors of human disease. Numerous studies have investigated the chemical composition of skin odors, and various sampling methods have been used for this purpose. The literature shows that the chemical profile of skin volatiles varies greatly among studies, and the use of different sampling procedures is probably responsible for some of these variations. To our knowledge, this is the first review focused on human skin volatile compounds. We detail the different sampling techniques, each with its own set of advantages and disadvantages, which have been used for the collection of skin odors from different parts of the human body. We present the main skin volatile compounds found in these studies, with particular emphasis on the most frequently studied body regions, axillae, hands, and feet. We propose future directions for promising experimental studies on odors from human skin, particularly in relation to the chemical ecology of blood-sucking insects.

The use of allodermis prepared from Euro skin bank to prepare autologous tissue engineered skin for clinical use.

Science.gov (United States)

Deshpande, P; Ralston, D R; MacNeil, S

2013-09-01

Over the past two decades a range of 3D models for human skin have been described. Some include native collagen and intrinsic basement membrane proteins and fibroblasts, others are based on xenogeneic collagen or synthetic supports often without fibroblasts. The aim of this study was to look at the influence of media calcium, basement membrane and fibroblasts on the quality of 3D tissue engineered skin produced using human de-epidermized acellular dermis. In this study we deliberately used Euro skin as the source of the donor dermis to examine to what extent this could provide an effective dermal substrate for producing 3D skin for clinical use. Keratinocytes were cultured in the presence and absence of fibroblasts and both with and without basement membrane on decellularized dermis at calcium concentrations ranging from 250μM to 1.6mM over a period of 14 days. Results showed the formation of a well attached epithelium with many of the features of normal skin in the presence of a basement membrane. This was largely independent of the presence of fibroblasts and not greatly influenced by the concentration of calcium in the media. However there was a clear requirement for physiological levels of calcium in the formation of a stratified epithelium in the absence of a basement membrane. Copyright © 2013 Elsevier Ltd and ISBI. All rights reserved.

Human normal tissue reactions in radiotherapy

International Nuclear Information System (INIS)

Taniike, Keiko

1990-01-01

Acute and late normal tissue reactions in radiotherapy have not been considered to be major problems with conventional fractionation. But they may cause certain problems when newer schedules such as hyperfractionation or accelerated fractionation are used. In opposing parallel radiotherapy, the dose fractionation of skin or subcutaneous connective tissue are different between in one portal and two portals daily. So we examined acute skin erythema and late connective tissue fibrosis in the two groups (one and two portals) of the patients with uterus cancer. Acute skin erythema and late connective tissue fibrosis were slightly stronger in case of one portal daily. In relation to the anatomical site of skin, acute skin erythema was stronger at the buttocks than the lower abdomen, but late fibrosis was reverse to that. So the degree of acute skin erythema did not predict the degree of late connective tissue fibrosis. The number of Time Dose Fractionation Factor could roughly estimate the degree of erythema and fibrosis. Late fibrosis in 36 fractions increased with an increase of abdominal thickness, but acute erythema did not. (author)

Future Prospects for Scaffolding Methods and Biomaterials in Skin Tissue Engineering: A Review

Directory of Open Access Journals (Sweden)

Atul A. Chaudhari

2016-11-01

Full Text Available Over centuries, the field of regenerative skin tissue engineering has had several advancements to facilitate faster wound healing and thereby restoration of skin. Skin tissue regeneration is mainly based on the use of suitable scaffold matrices. There are several scaffold types, such as porous, fibrous, microsphere, hydrogel, composite and acellular, etc., with discrete advantages and disadvantages. These scaffolds are either made up of highly biocompatible natural biomaterials, such as collagen, chitosan, etc., or synthetic materials, such as polycaprolactone (PCL, and poly-ethylene-glycol (PEG, etc. Composite scaffolds, which are a combination of natural or synthetic biomaterials, are highly biocompatible with improved tensile strength for effective skin tissue regeneration. Appropriate knowledge of the properties, advantages and disadvantages of various biomaterials and scaffolds will accelerate the production of suitable scaffolds for skin tissue regeneration applications. At the same time, emphasis on some of the leading challenges in the field of skin tissue engineering, such as cell interaction with scaffolds, faster cellular proliferation/differentiation, and vascularization of engineered tissues, is inevitable. In this review, we discuss various types of scaffolding approaches and biomaterials used in the field of skin tissue engineering and more importantly their future prospects in skin tissue regeneration efforts.

Cellulose/poly-(m-phenylene isophthalamide) porous film as a tissue-engineered skin bioconstruct

Science.gov (United States)

Lee, Jae Woong; Han, Sung Soo; Zo, Sum Mi; Choi, Soon Mo

2018-06-01

Regarding the porous structure, coagulated cellulose may not provide sufficient voids for cell proliferation, resulting in tissue growth. For this reason, it was blended with poly(m-phenylene isophthalamide) (PMIA), which could produce a porous structure in the resulting construct. The aim of this study was to confirm the potential of a novel cellulose/PMIA porous film as a tissue-engineered bioconstruct for impaired skin. The films were fabricated by a coagulation process added with a peel-off method, and the structural, mechanical properties were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and capillary flow porometry. CRL-2310 human keratinocytes were used to determine the biocompatibility of the prepared films. The attachment and proliferation of cells were investigated by scanning electron microscopy, DAPI staining, and a cell viability assay. The results show that cellulose/PMIA porous films have potential use as wound matrices for skin tissue genesis.

Transport of beta-aminopropionitrile through intact skin or scar tissue

International Nuclear Information System (INIS)

Gibeault, J.D.; Cravens, R.B. Jr.; Chvapil, M.

1989-01-01

A lathyrogen, [ 14 C]aminopropionitrile (beta APN), was administered to 34 rats either in K-Y jelly or saline vehicles onto intact shaven skin or onto a healed splinted deep excision wound. The dynamics of beta APN transport and content in the skin or repair tissue was observed after 2, 5, 8, and 24 hr of topical administration. The repair tissue quickly absorbed the lathyrogen and reached maximum at the 2-hr sampling. The content of beta APN in the repair tissue was twice as high as that in K-Y jelly vehicle and remained high and stable for at least 24 hr only when beta APN was administered through a saline vehicle. The transport of beta APN through intact skin, irrespective of the vehicle tested, was slow and continuously increased. The study showed that almost 20% of the beta APN administered onto the wounded skin area was transported into the repair tissue within 2 hr. We suggest that, due to the absence of epidermal stratum corneum from the repair tissue, drugs, such as beta APN, penetrate quickly into the wound

Enhancement of keratinocyte performance in the production of tissue-engineered skin using a low-calcium medium.

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Hernon, Catherine A; Harrison, Caroline A; Thornton, Daniel J A; MacNeil, Sheila

2007-01-01

The success of laboratory-expanded autologous keratinocytes for the treatment of severe burn injuries is often compromised by their lack of dermal remnants and failure to establish a secure dermo-epidermal junction on the wound bed. We have developed a tissue-engineered skin substitute for in vivo use, based on a sterilized donor human dermis seeded with autologous keratinocytes and fibroblasts. However, culture rates are currently too slow for clinical use in acute burns. Our aim in this study was to increase the rate of production of tissue-engineered skin. Two approaches were explored: one using a commercial low-calcium media and the other supplementing well-established media for keratinocyte culture with the calcium-chelating agent ethylene glutamine tetra-acetic acid (EGTA). Using commercial low-calcium media for both the initial cell culture and subsequent culture of tissue-engineered skin did not produce tissue suitable for clinical use. However, it was possible to enhance the initial proliferation of keratinocytes and to increase their horizontal migration in tissue-engineered skin by supplementing established culture medium with 0.04 mM EGTA without sacrificing epidermal attachment and differentiation. Enhancement of keratinocyte migration with EGTA was also maximal in the absence of fibroblasts or basement membrane.

Tissue engineered skin substitutes created by laser-assisted bioprinting form skin-like structures in the dorsal skin fold chamber in mice.

Directory of Open Access Journals (Sweden)

Stefanie Michael

Full Text Available Tissue engineering plays an important role in the production of skin equivalents for the therapy of chronic and especially burn wounds. Actually, there exists no (cellularized skin equivalent which might be able to satisfactorily mimic native skin. Here, we utilized a laser-assisted bioprinting (LaBP technique to create a fully cellularized skin substitute. The unique feature of LaBP is the possibility to position different cell types in an exact three-dimensional (3D spatial pattern. For the creation of the skin substitutes, we positioned fibroblasts and keratinocytes on top of a stabilizing matrix (Matriderm®. These skin constructs were subsequently tested in vivo, employing the dorsal skin fold chamber in nude mice. The transplants were placed into full-thickness skin wounds and were fully connected to the surrounding tissue when explanted after 11 days. The printed keratinocytes formed a multi-layered epidermis with beginning differentiation and stratum corneum. Proliferation of the keratinocytes was mainly detected in the suprabasal layers. In vitro controls, which were cultivated at the air-liquid-interface, also exhibited proliferative cells, but they were rather located in the whole epidermis. E-cadherin as a hint for adherens junctions and therefore tissue formation could be found in the epidermis in vivo as well as in vitro. In both conditions, the printed fibroblasts partly stayed on top of the underlying Matriderm® where they produced collagen, while part of them migrated into the Matriderm®. In the mice, some blood vessels could be found to grow from the wound bed and the wound edges in direction of the printed cells. In conclusion, we could show the successful 3D printing of a cell construct via LaBP and the subsequent tissue formation in vivo. These findings represent the prerequisite for the creation of a complex tissue like skin, consisting of different cell types in an intricate 3D pattern.

Skin and soft-tissue infec tions

African Journals Online (AJOL)

2010-06-01

Jun 1, 2010 ... Patients with skin and soft-tissue infections (SSTIs) often initially present to family physicians. ..... Nosocomial infections are often caused by MRSA or mixed .... site infections are good hand hygiene, good surgical technique.

The Ability of Tissue Engineered Skin Accelerating the Closure of Different Wound

Institute of Scientific and Technical Information of China (English)

无

2005-01-01

1 IntroductionIn the past several decades, a number of reseacher have described the principal efficacy of tissue engineered skin to promote wound healing of venous and diabetic ulcers. But the true value of tissue-engineered skin products in different wound care remains yet to be more clearly defined. In this trial, we analysis the effective of tissue-engineered skin (ActivSkin) in the management of burns, donor sites and ulcers, which were also the frequently injury caused with warfare, disaster and terror...

Importance of good manufacturing practices in microbiological monitoring in processing human tissues for transplant.

Science.gov (United States)

Pianigiani, Elisa; Ierardi, Francesca; Fimiani, Michele

2013-12-01

Skin allografts represent an important therapeutic resource in the treatment of severe skin loss. The risk associated with application of processed tissues in humans is very low, however, human material always carries the risk of disease transmission. To minimise the risk of contamination of grafts, processing is carried out in clean rooms where air quality is monitored. Procedures and quality control tests are performed to standardise the production process and to guarantee the final product for human use. Since we only validate and distribute aseptic tissues, we conducted a study to determine what type of quality controls for skin processing are the most suitable for detecting processing errors and intercurrent contamination, and for faithfully mapping the process without unduly increasing production costs. Two different methods for quality control were statistically compared using the Fisher exact test. On the basis of the current study we selected our quality control procedure based on pre- and post-processing tissue controls, operator and environmental controls. Evaluation of the predictability of our control methods showed that tissue control was the most reliable method of revealing microbial contamination of grafts. We obtained 100 % sensitivity by doubling tissue controls, while maintaining high specificity (77 %).

Elastin hydrolysate derived from fish enhances proliferation of human skin fibroblasts and elastin synthesis in human skin fibroblasts and improves the skin conditions.

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Shiratsuchi, Eri; Nakaba, Misako; Yamada, Michio

2016-03-30

Recent studies have shown that certain peptides significantly improve skin conditions, such as skin elasticity and the moisture content of the skin of healthy woman. This study aimed to investigate the effects of elastin hydrolysate on human skin. Proliferation and elastin synthesis were evaluated in human skin fibroblasts exposed to elastin hydrolysate and proryl-glycine (Pro-Gly), which is present in human blood after elastin hydrolysate ingestion. We also performed an ingestion test with elastin hydrolysate in humans and evaluated skin condition. Elastin hydrolysate and Pro-Gly enhanced the proliferation of fibroblasts and elastin synthesis. Maximal proliferation response was observed at 25 ng mL(-1) Pro-Gly. Ingestion of elastin hydrolysate improved skin condition, such as elasticity, number of wrinkles, and blood flow. Elasticity improved by 4% in the elastin hydrolysate group compared with 2% in the placebo group. Therefore, elastin hydrolysate activates human skin fibroblasts and has beneficial effects on skin conditions. © 2015 Society of Chemical Industry.

Absorption of human skin and its detecting platform in the process of laser cosmetology

Science.gov (United States)

Zhang, Yong-Lin; Ouyang, Li; Wang, Yang

2000-10-01

Because of the melanin, hemoglobin and water molecules, etc. contained, light absorption of human skin tissue changes with wavelength of light. This is the principle used in laser cosmetology for treating pigment diseases and vascular lesion diseases as well as skin decoration such as body tattooing, eyebrow tattooing, etc. The parameters of treatment used in laser cosmetology principally come from the research of the skin tissue optical characteristics of whites, and it is not suitable for the Oriental. The absorption spectrum of yellow race alive skin has been researched. The detecting platform for use in the measuring of vivi-tissue absorption spectrum has been developed which using opto-electronic nondestructive testing and virtual instrument techniques. The degree of pathological changes of skin can be detected by this platform also, thus the shortcoming of dosage selection in laser clinical treatments which have been decided only by naked eye observation and past experience of doctors can be solved.

3D bioprinting of functional human skin: production and in vivo analysis.

Science.gov (United States)

Cubo, Nieves; Garcia, Marta; Del Cañizo, Juan F; Velasco, Diego; Jorcano, Jose L

2016-12-05

Significant progress has been made over the past 25 years in the development of in vitro-engineered substitutes that mimic human skin, either to be used as grafts for the replacement of lost skin, or for the establishment of in vitro human skin models. In this sense, laboratory-grown skin substitutes containing dermal and epidermal components offer a promising approach to skin engineering. In particular, a human plasma-based bilayered skin generated by our group, has been applied successfully to treat burns as well as traumatic and surgical wounds in a large number of patients in Spain. There are some aspects requiring improvements in the production process of this skin; for example, the relatively long time (three weeks) needed to produce the surface required to cover an extensive burn or a large wound, and the necessity to automatize and standardize a process currently performed manually. 3D bioprinting has emerged as a flexible tool in regenerative medicine and it provides a platform to address these challenges. In the present study, we have used this technique to print a human bilayered skin using bioinks containing human plasma as well as primary human fibroblasts and keratinocytes that were obtained from skin biopsies. We were able to generate 100 cm 2 , a standard P100 tissue culture plate, of printed skin in less than 35 min (including the 30 min required for fibrin gelation). We have analysed the structure and function of the printed skin using histological and immunohistochemical methods, both in 3D in vitro cultures and after long-term transplantation to immunodeficient mice. In both cases, the generated skin was very similar to human skin and, furthermore, it was indistinguishable from bilayered dermo-epidermal equivalents, handmade in our laboratories. These results demonstrate that 3D bioprinting is a suitable technology to generate bioengineered skin for therapeutical and industrial applications in an automatized manner.

Amnion s and radio-sterilized porcine skin use as potential matrices for the development of human skin substitutes

International Nuclear Information System (INIS)

Martinez P, M. E.; Reyes F, M. L.; Reboyo B, D.; Velasquillo M, M. C.; Sanchez S, R.; Brena M, A. M.; Ibarra P, J. C.

2014-10-01

The injuries by burns constitute a primordial problem of public health; they cause a high mortality index, severe physical and psychological disability, etc. The autologous skin transplant is the replacement therapy recommended for its treatment, but in patients that present a high percentage of burnt skin; this is not possible to carry out. Another strategy is the transplant of donated skin; however, due to the little donation that exists in our country is not very feasible to apply this treatment. A challenge of the tissues engineering is to develop biological skin substitutes, based on cells and amnion s, favoring the cutaneous regeneration and quick repair of injuries, diminishing this way the hospitalization expenses. At present skin substitutes that can equal to the same skin do not exist. On the other hand, the mesenchymal stromal cells (Msc) represent an alternative to achieve this objective; since has been demonstrated that the Msc participate in the tissue repair by means of inhibition of pro-inflammatory cytokines and differentiation to dermal fibroblasts and keratinocytes. To apply the Msc in cutaneous injuries a support material is required that to allow transplanting these cells to a lesion or burn. The radio-sterilized human amnion and the radio-sterilized porcine skin, processed by the Radio-Sterilized Tissues Bank of the Instituto Nacional de Investigaciones Nucleares (ININ), are biomaterials that are used as temporary cutaneous coverings. We suppose that these two matrices will be appropriate for the growth and maintenance in cultivation of the Msc, to generate two biological skin substitutes, in collaboration with the Biotechnology Laboratory of the Instituto Nacional de Rehabilitacion. (Author)

Novel keratin modified bacterial cellulose nanocomposite production and characterization for skin tissue engineering.

Science.gov (United States)

Keskin, Zalike; Sendemir Urkmez, Aylin; Hames, E Esin

2017-06-01

As it is known that bacterial cellulose (BC) is a biocompatible and natural biopolymer due to which it has a large set of biomedical applications. But still it lacks some desired properties, which limits its uses in many other applications. Therefore, the properties of BC need to be boosted up to an acceptable level. Here in this study for the first time, a new natural nanocomposite was produced by the incorporating keratin (isolated from human hair) to the BC (produced by Acetobacter xylinum) to enhance dermal fibroblast cells' attachment. Two different approaches were used in BC based nanocomposite production: in situ and post modifications. BC/keratin nanocomposites were characterized using SEM, FTIR, EDX, XRD, DSC and XPS analyses. Both production methods have yielded successful results for production of BC based nanocomposite-containing keratin. In vitro cell culture experiments performed with human skin keratinocytes and human skin fibroblast cells indicate the potential of the novel BC/keratin nanocomposites for use in skin tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

Collagen-chitosan scaffold - Lauric acid plasticizer for skin tissue engineering on burn cases

Science.gov (United States)

Widiyanti, Prihartini; Setyadi, Ewing Dian; Rudyardjo, Djony Izak

2017-02-01

The prevalence of burns in the world is more than 800 cases per one million people each year and this is the second highest cause of death due to trauma after traffic accident. Many studies are turning to skin substitute methods of tissue engineering. The purpose of this study is to determine the composition of the collagen, chitosan, and lauric acid scaffold, as well as knowing the results of the characterization of the scaffold. The synthesis of chitosan collagen lauric acid scaffold as a skin tissue was engineered using freeze dried method. Results from making of collagen chitosan lauric acid scaffold was characterized physically, biologically and mechanically by SEM, cytotoxicity, biodegradation, and tensile strength. From the morphology test, the result obtained is that pore diameter size ranges from 94.11 to 140.1 µm for samples A,B,C,D, which are in the range of normal pore size 63-150 µm, while sample E has value below the standard which is about 37.87 to 47.36 µm. From cytotoxicity assay, the result obtained is the percentage value of living cells between 20.11 to 21.51%. This value is below 50% the standard value of living cells. Incompatibility is made possible because of human error mainly the replication of washing process over the standard. Degradation testing obtained values of 19.44% - 40% by weight which are degraded during the 7 days of observation. Tensile test results obtained a range of values of 0.192 - 3.53 MPa. Only sample A (3.53 MPa) and B (1.935 MPa) meet the standard values of skin tissue scaffold that is 1-24 MPa. Based on the results of the characteristics of this study, composite chitosan collagen scaffold with lauric acid plasticizer has a potential candidate for skin tissue engineering for skin burns cases.

Characterization of innate lymphoid cells in human skin and blood demonstrates increase of NKp44+ ILC3 in psoriasis.

Science.gov (United States)

Villanova, Federica; Flutter, Barry; Tosi, Isabella; Grys, Katarzyna; Sreeneebus, Hemawtee; Perera, Gayathri K; Chapman, Anna; Smith, Catherine H; Di Meglio, Paola; Nestle, Frank O

2014-04-01

Innate lymphoid cells (ILCs) are increasingly appreciated as key regulators of tissue immunity. However, their role in human tissue homeostasis and disease remains to be fully elucidated. Here we characterize the ILCs in human skin from healthy individuals and from the inflammatory skin disease psoriasis. We show that a substantial proportion of IL-17A and IL-22 producing cells in the skin and blood of normal individuals and psoriasis patients are CD3-negative innate lymphocytes. Deep immunophenotyping of human ILC subsets showed a statistically significant increase in the frequency of circulating NKp44+ ILC3 in the blood of psoriasis patients compared with healthy individuals or atopic dermatitis patients. More than 50% of circulating NKp44+ ILC3 expressed cutaneous lymphocyte-associated antigen, indicating their potential for skin homing. Analysis of skin tissue revealed a significantly increased frequency of total ILCs in the skin compared with blood. Moreover, the frequency of NKp44+ ILC3 was significantly increased in non-lesional psoriatic skin compared with normal skin. A detailed time course of a psoriasis patient treated with anti-tumor necrosis factor showed a close association between therapeutic response, decrease in inflammatory skin lesions, and decrease of circulating NKp44+ ILC3. Overall, data from this initial observational study suggest a potential role for NKp44+ ILC3 in psoriasis pathogenesis.

In vitro differentiation of human skin-derived multipotent stromal cells into putative endothelial-like cells

Directory of Open Access Journals (Sweden)

Vishnubalaji Radhakrishnan

2012-01-01

Full Text Available Abstract Background Multipotent stem cells have been successfully isolated from various tissues and are currently utilized for tissue-engineering and cell-based therapies. Among the many sources, skin has recently emerged as an attractive source for multipotent cells because of its abundance. Recent literature showed that skin stromal cells (SSCs possess mesoderm lineage differentiation potential; however, the endothelial differentiation and angiogenic potential of SSC remains elusive. In our study, SSCs were isolated from human neonatal foreskin (hNFSSCs and adult dermal skin (hADSSCs using explants cultures and were compared with bone marrow (hMSC-TERT and adipose tissue-derived mesenchymal stem cells (hADMSCs for their potential differentiation into osteoblasts, adipocytes, and endothelial cells. Results Concordant with previous studies, both MSCs and SSCs showed similar morphology, surface protein expression, and were able to differentiate into osteoblasts and adipocytes. Using an endothelial induction culture system combined with an in vitro matrigel angiogenesis assay, hNFSSCs and hADSSCs exhibited the highest tube-forming capability, which was similar to those formed by human umbilical vein endothelial cells (HUVEC, with hNFSSCs forming the most tightly packed, longest, and largest diameter tubules among the three cell types. CD146 was highly expressed on hNFSSCs and HUVEC followed by hADSSCs, and hMSC-TERT, while its expression was almost absent on hADMSCs. Similarly, higher vascular density (based on the expression of CD31, CD34, vWF, CD146 and SMA was observed in neonatal skin, followed by adult dermal skin and adipose tissue. Thus, our preliminary data indicated a plausible relationship between vascular densities, and the expression of CD146 on multipotent cells derived from those tissues. Conclusions Our data is the first to demonstrate that human dermal skin stromal cells can be differentiated into endothelial lineage. Hence, SSCs

Three-dimensional analysis and classification of arteries in the skin and subcutaneous adipofascial tissue by computer graphics imaging.

Science.gov (United States)

Nakajima, H; Minabe, T; Imanishi, N

1998-09-01

To develop new types of surgical flaps that utilize portions of the skin and subcutaneous tissue (e.g., a thin flap or an adipofascial flap), three-dimensional investigation of the vasculature in the skin and subcutaneous tissue has been anticipated. In the present study, total-body arterial injection and three-dimensional imaging of the arteries by computer graphics were performed. The full-thickness skin and subcutaneous adipofascial tissue samples, which were obtained from fresh human cadavers injected with radio-opaque medium, were divided into three distinct layers. Angiograms of each layer were introduced into a personal computer to construct three-dimensional images. On a computer monitor, each artery was shown color-coded according to the three portions: the deep adipofascial layer, superficial adipofascial layer, and dermis. Three-dimensional computerized images of each artery in the skin and subcutaneous tissue revealed the components of each vascular plexus and permitted their classification into six types. The distribution of types in the body correlated with the tissue mobility of each area. Clinically, appreciation of the three-dimensional structure of the arteries allowed the development of several new kinds of flaps.

RNA isolation for transcriptomics of human and mouse small skin biopsies

Directory of Open Access Journals (Sweden)

Breit Timo M

2011-10-01

Full Text Available Abstract Background Isolation of RNA from skin biopsies presents a challenge, due to the tough nature of skin tissue and a high presence of RNases. As we lacked the dedicated equipment, i.e. homogenizer or bead-beater, needed for the available RNA from skin isolation methods, we adapted and tested our zebrafish single-embryo RNA-isolation protocol for RNA isolation from skin punch biopsies. Findings We tested our new RNA-isolation protocol in two experiments: a large-scale study with 97 human skin samples, and a small study with 16 mouse skin samples. Human skin was sampled with 4.0 mm biopsy punches and for the mouse skin different punch diameter sizes were tested; 1.0, 1.5, 2.0, and 2.5 mm. The average RNA yield in human samples was 1.5 μg with an average RNA quality RIN value of 8.1. For the mouse biopsies, the average RNA yield was 2.4 μg with an average RIN value of 7.5. For 96% of the human biopsies and 100% of the mouse biopsies we obtained enough high-quality RNA. The RNA samples were successfully tested in a transcriptomics analysis using the Affymetrix and Roche NimbleGen platforms. Conclusions Using our new RNA-isolation protocol, we were able to consistently isolate high-quality RNA, which is apt for further transcriptomics analysis. Furthermore, this method is already useable on biopsy material obtained with a punch diameter as small as 1.5 mm.

Evaluation of light scattering properties and chromophore concentrations in skin tissue based on diffuse reflectance signals at isosbestic wavelengths of hemoglobin

Science.gov (United States)

Yokokawa, Takumi; Nishidate, Izumi

2016-04-01

We investigate a method to evaluate light-scattering properties and chromophore concentrations in human skin tissue through diffuse reflectance spectroscopy using the reflectance signals acquired at isosbestic wavelengths of hemoglobin (420, 450, 500, and 585 nm). In the proposed method, Monte Carlo simulation-based empirical formulas are used to specify the scattering parameters of skin tissue, such as the scattering amplitude a and the scattering power b, as well as the concentration of melanin C m and the total blood concentration C tb. The use of isosbestic wavelengths of hemoglobin enables the values of C m, C tb, a, and b to be estimated independently of the oxygenation of hemoglobin. The spectrum of the reduced scattering coefficient is reconstructed from the scattering parameters. Experiments using in vivo human skin tissues were performed to confirm the feasibility of the proposed method for evaluating the changes in scattering properties and chromophore concentrations in skin tissue. The experimental results revealed that light scattering is significantly reduced by the application of a glycerol solution, which indicates an optical clearing effect due to osmotic dehydration and the matching of the refractive indices of scatterers in the epidermis.

Near infrared laser penetration and absorption in human skin

Science.gov (United States)

Nasouri, Babak; Murphy, Thomas E.; Berberoglu, Halil

2014-02-01

For understanding the mechanisms of low level laser/light therapy (LLLT), accurate knowledge of light interaction with tissue is necessary. In this paper, we present a three dimensional, multi-layer Monte Carlo simulation tool for studying light penetration and absorption in human skin. The skin is modeled as a three-layer participating medium, namely epidermis, dermis, and subcutaneous, where its geometrical and optical properties are obtained from the literature. Both refraction and reflection are taken into account at the boundaries according to Snell's law and Fresnel relations. A forward Monte Carlo method was implemented and validated for accurately simulating light penetration and absorption in absorbing and anisotropically scattering media. Local profiles of light penetration and volumetric absorption densities were simulated for uniform as well as Gaussian profile beams with different spreads at 155 mW average power over the spectral range from 1000 nm to 1900 nm. The results show the effects of beam profiles and wavelength on the local fluence within each skin layer. Particularly, the results identify different wavelength bands for targeted deposition of power in different skin layers. Finally, we show that light penetration scales well with the transport optical thickness of skin. We expect that this tool along with the results presented will aid researchers resolve issues related to dose and targeted delivery of energy in tissues for LLLT.

A comparison of scaffold-free and scaffold-based reconstructed human skin models as alternatives to animal use.

Science.gov (United States)

Kinikoglu, Beste

2017-12-01

Tissue engineered full-thickness human skin substitutes have various applications in the clinic and in the laboratory, such as in the treatment of burns or deep skin defects, and as reconstructed human skin models in the safety testing of drugs and cosmetics and in the fundamental study of skin biology and pathology. So far, different approaches have been proposed for the generation of reconstructed skin, each with its own advantages and disadvantages. Here, the classic tissue engineering approach, based on cell-seeded polymeric scaffolds, is compared with the less-studied cell self-assembly approach, where the cells are coaxed to synthesise their own extracellular matrix (ECM). The resulting full-thickness human skin substitutes were analysed by means of histological and immunohistochemical analyses. It was found that both the scaffold-free and the scaffold-based skin equivalents successfully mimicked the functionality and morphology of native skin, with complete epidermal differentiation (as determined by the expression of filaggrin), the presence of a continuous basement membrane expressing collagen VII, and new ECM deposition by dermal fibroblasts. On the other hand, the scaffold-free model had a thicker epidermis and a significantly higher number of Ki67-positive proliferative cells, indicating a higher capacity for self-renewal, as compared to the scaffold-based model. 2017 FRAME.

Skin friction: a novel approach to measuring in vivo human skin

OpenAIRE

Veijgen, N.K.

2013-01-01

The human skin plays an important role in people’s lives. It is in constant interaction with the environment, clothing and consumer products. This thesis discusses one of the parameters in the interaction between the human skin in vivo and other materials: skin friction. The thesis is divided into three parts. The first part is an introduction to skin friction and to current knowledge on skin friction. The second part presents the RevoltST, the tribometer that was specially developed for skin...

Non-enzymatic NO production in human skin: effect of UVA on cutaneous NO stores

NARCIS (Netherlands)

Suschek, C.; Opländer, C.; van Faassen, E.E.H.

2009-01-01

Nitric oxide (NO) in human skin has been under investigation since first reports of NOS expression in skin tissue in 1992 [1]. NO plays a key role in the dermal response to external stimuli such as heat, ultraviolet (UV) light, or infection, and in healing of abrasions, lesions or burns. Recently, a

Preparation of Artificial Skin that Mimics Human Skin Surface and Mechanical Properties.

Science.gov (United States)

Shimizu, Rana; Nonomura, Yoshimune

2018-01-01

We have developed an artificial skin that mimics the morphological and mechanical properties of human skin. The artificial skin comprises a polyurethane block possessing a microscopically rough surface. We evaluated the tactile sensations when skin-care cream was applied to the artificial skin. Many subjects perceived smooth, moist, and soft feels during the application process. Cluster analysis showed that these characteristic tactile feels are similar to those when skin-care cream is applied to real human skin. Contact angle analysis showed that an oil droplet spread smoothly on the artificial skin surface, which occurred because there were many grooves several hundred micrometers in width on the skin surface. In addition, when the skin-care cream was applied, the change in frictional force during the dynamic friction process increased. These wetting and frictional properties are important factors controlling the similarity of artificial skin to real human skin.

Using a portable terahertz spectrometer to measure the optical properties of in vivo human skin

Science.gov (United States)

Echchgadda, Ibtissam; Grundt, Jessica A.; Tarango, Melissa; Ibey, Bennett L.; Tongue, Thomas; Liang, Min; Xin, Hao; Wilmink, Gerald J.

2013-12-01

Terahertz (THz) time-domain spectroscopy systems permit the measurement of a tissue's hydration level. This feature makes THz spectrometers excellent tools for the noninvasive assessment of skin; however, current systems are large, heavy and not ideal for clinical settings. We previously demonstrated that a portable, compact THz spectrometer permitted measurement of porcine skin optical properties that were comparable to those collected with conventional systems. In order to move toward human use of this system, the goal for this study was to measure the absorption coefficient (μa) and index of refraction (n) of human subjects in vivo. Spectra were collected from 0.1 to 2 THz, and measurements were made from skin at three sites: the palm, ventral and dorsal forearm. Additionally, we used a multiprobe adapter system to measure each subject's skin hydration levels, transepidermal water loss, and melanin concentration. Our results suggest that the measured optical properties varied considerably for skin tissues that exhibited dissimilar hydration levels. These data provide a framework for using compact THz spectrometers for clinical applications.

Characterization of innate lymphoid cells (ILC) in human skin and blood demonstrates increase of NKp44+ ILC3 in psoriasis

Science.gov (United States)

Tosi, Isabella; Grys, Katarzyna; Sreeneebus, Hemawtee; Perera, Gayathri K; Chapman, Anna; Smith, Catherine H; Di Meglio, Paola; Nestle, Frank O

2013-01-01

Innate lymphoid cells (ILC) are increasingly appreciated as key regulators of tissue immunity. However, their role in human tissue homeostasis and disease remains to be fully elucidated. Here we characterise the ILC in human skin from healthy individuals and from the inflammatory skin disease psoriasis. We show that a substantial proportion of IL-17A and IL-22 producing cells in skin and blood of normal individuals and psoriasis patients are CD3 negative innate lymphocytes. Deep immunophenotyping of human ILC subsets showed a statistically significant increase in the frequency of circulating NKp44+ ILC3 in blood of psoriasis patients compared to healthy individuals or atopic dermatitis patients. More than 50% of circulating NKp44+ ILC3 expressed cutaneous lymphocyte-associated antigen indicating their potential for skin homing. Analysis of skin tissue revealed a significantly increased frequency of total ILC in skin compared to blood. Moreover the frequency of NKp44+ ILC3 was significantly increased in non-lesional psoriatic skin compared to normal skin. A detailed time course of a psoriasis patient treated with anti-TNF showed a close association between therapeutic response, decrease in inflammatory skin lesions, and decrease of circulating NKp44+ ILC3. Overall, data from this initial observational study suggest a potential role for NKp44+ ILC3 in psoriasis pathogenesis. PMID:24352038

Bioactive reagents used in mesotherapy for skin rejuvenation in vivo induce diverse physiological processes in human skin fibroblasts in vitro- a pilot study.

Science.gov (United States)

Jäger, Claudia; Brenner, Christiane; Habicht, Jüri; Wallich, Reinhard

2012-01-01

The promise of mesotherapy is maintenance and/or recovery of a youthful skin with a firm, bright and moisturized texture. Currently applied medications employ microinjections of hyaluronic acid, vitamins, minerals and amino acids into the superficial layer of the skin. However, the molecular and cellular processes underlying mesotherapy are still elusive. Here we analysed the effect of five distinct medication formulas on pivotal parameters involved in skin ageing, that is collagen expression, cell proliferation and morphological changes using normal human skin fibroblast cultures in vitro. Whereas in the presence of hyaluronic acid, NCTF135(®) and NCTF135HA(®) , cell proliferation was comparable to control cultures; however, with higher expression of collagen type-1, matrix metalloproteinase-1 and tissue inhibitor of matrix metalloproteinase-1, addition of Soluvit(®) N and Meso-BK led to apoptosis and/or necrosis of human fibroblasts. The data indicate that bioactive reagents currently applied for skin rejuvenation elicit strikingly divergent physiological processes in human skin fibroblast in vitro. © 2011 John Wiley & Sons A/S.

[NEW PROGRESS OF ACELLULAR FISH SKIN AS NOVEL TISSUE ENGINEERED SCAFFOLD].

Science.gov (United States)

Wei, Xiaojuan; Wang, Nanping; He, Lan; Guo, Xiuyu; Gu, Qisheng

2016-11-08

To review the recent research progress of acellular fish skin as a tissue engineered scaffold, and to analyze the feasibility and risk management in clinical application. The research and development, application status of acellular fish skin as a tissue engineered scaffold were comprehensively analyzed, and then several key points were put forward. Acellular fish skin has a huge potential in clinical practice as novel acellular extracellular matrix, but there have been no related research reports up to now in China. As an emerging point of translational medicine, investigation of acellular fish skin is mainly focused on artificial skin, surgical patch, and wound dressings. Development of acellular fish skin-based new products is concerned to be clinical feasible and necessary, but a lot of applied basic researches should be carried out.

Skin bioprinting: a novel approach for creating artificial skin from synthetic and natural building blocks.

Science.gov (United States)

Augustine, Robin

2018-05-12

Significant progress has been made over the past few decades in the development of in vitro-engineered substitutes that mimic human skin, either as grafts for the replacement of lost skin, or for the establishment of in vitro human skin models. Tissue engineering has been developing as a novel strategy by employing the recent advances in various fields such as polymer engineering, bioengineering, stem cell research and nanomedicine. Recently, an advancement of 3D printing technology referred as bioprinting was exploited to make cell loaded scaffolds to produce constructs which are more matching with the native tissue. Bioprinting facilitates the simultaneous and highly specific deposition of multiple types of skin cells and biomaterials, a process that is lacking in conventional skin tissue-engineering approaches. Bioprinted skin substitutes or equivalents containing dermal and epidermal components offer a promising approach in skin bioengineering. Various materials including synthetic and natural biopolymers and cells with or without signalling molecules like growth factors are being utilized to produce functional skin constructs. This technology emerging as a novel strategy to overcome the current bottle-necks in skin tissue engineering such as poor vascularization, absence of hair follicles and sweat glands in the construct.

Human age and skin physiology shape diversity and abundance of Archaea on skin.

Science.gov (United States)

Moissl-Eichinger, Christine; Probst, Alexander J; Birarda, Giovanni; Auerbach, Anna; Koskinen, Kaisa; Wolf, Peter; Holman, Hoi-Ying N

2017-06-22

The human skin microbiome acts as an important barrier protecting our body from pathogens and other environmental influences. Recent investigations have provided evidence that Archaea are a constant but highly variable component of the human skin microbiome, yet factors that determine their abundance changes are unknown. Here, we tested the hypothesis that the abundance of archaea on human skin is influenced by human age and skin physiology by quantitative PCR of 51 different skin samples taken from human subjects of various age. Our results reveal that archaea are more abundant in human subjects either older than 60 years or younger than 12 years as compared to middle-aged human subjects. These results, together with results obtained from spectroscopy analysis, allowed us gain first insights into a potential link of lower sebum levels and lipid content and thus reduced skin moisture with an increase in archaeal signatures. Amplicon sequencing of selected samples revealed the prevalence of specific eury- and mainly thaumarchaeal taxa, represented by a core archaeome of the human skin.

Skin friction: a novel approach to measuring in vivo human skin

NARCIS (Netherlands)

Veijgen, N.K.

2013-01-01

The human skin plays an important role in people’s lives. It is in constant interaction with the environment, clothing and consumer products. This thesis discusses one of the parameters in the interaction between the human skin in vivo and other materials: skin friction. The thesis is divided into

Electroosmotic pore transport in human skin.

Science.gov (United States)

Uitto, Olivia D; White, Henry S

2003-04-01

To determine the pathways and origin of electroosmotic flow in human skin. Iontophoretic transport of acetaminophen in full thickness human cadaver skin was visualized and quantified by scanning electrochemical microscopy. Electroosmotic flow in the shunt pathways of full thickness skin was compared to flow in the pores of excised stratum corneum and a synthetic membrane pore. The penetration of rhodamine 6G into pore structures was investigated by laser scanning confocal microscopy. Electroosmotic transport is observed in shunt pathways in full thickness human skin (e.g., hair follicles and sweat glands), but not in pore openings of freestanding stratum corneum. Absolute values of the diffusive and iontophoretic pore fluxes of acetaminophen in full thickness human skin are also reported. Rhodamine 6G is observed to penetrate to significant depths (approximately 200 microm) along pore pathways. Iontophoresis in human cadaver skin induces localized electroosmotic flow along pore shunt paths. Electroosmotic forces arise from the passage of current through negatively charged mesoor nanoscale pores (e.g., gap functions) within cellular regions that define the pore structure beneath the stratum corneum.

In situ depletion of CD4(+) T cells in human skin by Zanolimumab

DEFF Research Database (Denmark)

Villadsen, L.S.; Skov, L.; Dam, T.N.

2007-01-01

CD4(+) T cells, in activated or malignant form, are involved in a number of diseases including inflammatory skin diseases such as psoriasis, and T cell lymphomas such as the majority of cutaneous T cell lymphomas (CTCL). Targeting CD4 with an antibody that inhibits and/or eliminates disease......-driving T cells in situ may therefore be a useful approach in the treatment of inflammatory and malignant skin diseases. Depletion of CD4(+) T cells in intact inflamed human skin tissue by Zanolimumab, a fully human therapeutic monoclonal antibody (IgG1, kappa) against CD4, was studied in a human psoriasis......(+), but not CD8(+) CD3(+) T cells. The capacity of Zanolimumab to deplete the CD4(+) T cells in the skin may be of importance in diseases where CD4(+) T cells play a central role. Indeed, in a phase II clinical trial Zanolimumab has shown a dose-dependent clinical response in patients with CTCL and the antibody...

Topical stabilized retinol treatment induces the expression of HAS genes and HA production in human skin in vitro and in vivo.

Science.gov (United States)

Li, Wen-Hwa; Wong, Heng-Kuan; Serrano, José; Randhawa, Manpreet; Kaur, Simarna; Southall, Michael D; Parsa, Ramine

2017-05-01

Skin Aging manifests primarily with wrinkles, dyspigmentations, texture changes, and loss of elasticity. During the skin aging process, there is a loss of moisture and elasticity in skin resulting in loss of firmness finally leading to skin sagging. The key molecule involved in skin moisture is hyaluronic acid (HA), which has a significant water-binding capacity. HA levels in skin decline with age resulting in decrease in skin moisture, which may contribute to loss of firmness. Clinical trials have shown that topically applied ROL effectively reduces wrinkles and helps retain youthful appearance. In the current study, ROL was shown to induce HA production and stimulates the gene expression of all three forms of hyaluronic acid synthases (HAS) in normal human epidermal keratinocytes monolayer cultures. Moreover, in human skin equivalent tissues and in human skin explants, topical treatment of tissues with a stabilized-ROL formulation significantly induced the gene expression of HAS mRNA concomitant with an increased HA production. Finally, in a vehicle-controlled human clinical study, histochemical analysis confirmed increased HA accumulation in the epidermis in ROL-treated human skin as compared to vehicle. These results show that ROL increases skin expression of HA, a significant contributing factor responsible for wrinkle formation and skin moisture, which decrease during aging. Taken together with the activity to increase collagen, elastin, and cell proliferation, these studies establish that retinol provides multi-functional activity for photodamaged skin.

Influence of probe pressure on diffuse reflectance spectra of human skin measured in vivo

Science.gov (United States)

Popov, Alexey P.; Bykov, Alexander V.; Meglinski, Igor V.

2017-11-01

Mechanical pressure superficially applied on the human skin surface by a fiber-optic probe influences the spatial distribution of blood within the cutaneous tissues. Upon gradual load of weight on the probe, a stepwise increase in the skin reflectance spectra is observed. The decrease in the load follows the similar inverse staircase-like tendency. The observed stepwise reflectance spectra changes are due to, respectively, sequential extrusion of blood from the topical cutaneous vascular beds and their filling afterward. The obtained results are confirmed by Monte Carlo modeling. This implies that pressure-induced influence during the human skin diffuse reflectance spectra measurements in vivo should be taken into consideration, in particular, in the rapidly developing area of wearable gadgets for real-time monitoring of various human body parameters.

[Skin and Soft Tissue Infections Due to Corynebacterium ulcerans - Case Reports].

Science.gov (United States)

Jenssen, Christian; Schwede, Ilona; Neumann, Volker; Pietsch, Cristine; Handrick, Werner

2017-10-01

History and clinical findings  We report on three patients suffering from skin and soft tissue infections of the legs due to toxigenic Corynebacterium ulcerans strains. In all three patients, there was a predisposition due to chronic diseases. Three patients had domestic animals (cat, dog) in their households. Investigations and diagnosis  A mixed bacterial flora including Corynebacterium ulcerans was found in wound swab samples. Diphtheric toxin was produced by the Corynebacterium ulcerans strains in all three cases. Treatment and course  In all three patients, successful handling of the skin and soft tissue infections was possible by combining local treatment with antibiotics. Diphtheria antitoxin was not administered in any case. Conclusion  Based on a review of the recent literature pathogenesis, clinical symptoms and signs, diagnostics and therapy of skin and soft tissue infections due to Corynebacterium ulcerans are discussed. Corynebacterium ulcerans should be considered as a potential cause of severe skin and soft tissue infections. Occupational or domestic animal contacts should be evaluated. © Georg Thieme Verlag KG Stuttgart · New York.

Efficient in vivo gene transfer to xenotransplanted human skin by lentivirus-mediated, but not by AAV-directed, gene delivery

DEFF Research Database (Denmark)

Jakobsen, Maria Vad; Askou, Anne Louise; Dokkedahl, Karin Stenderup

skin graft, and firefly luciferase expression was observed primarily in neighboring tissue beneath or surrounding the graft. In contrast, gene delivery by intradermally injected lentiviral vectors was efficient and led to extensive and persistent firefly luciferase expression within the human skin...... graft only. The study demonstrates limited capacity of single-stranded AAV vectors of six commonly used serotypes for gene delivery to human skin in vivo....

Clinical application of a tissue-cultured skin autograft: an alternative for the treatment of non-healing or slowly healing wounds?

Science.gov (United States)

Zöller, Nadja; Valesky, Eva; Butting, Manuel; Hofmann, Matthias; Kippenberger, Stefan; Bereiter-Hahn, Jürgen; Bernd, August; Kaufmann, Roland

2014-01-01

The treatment regime of non-healing or slowly healing wounds is constantly improving. One aspect is surgical defect coverage whereby mesh grafts and keratinocyte suspension are applied. Tissue-cultured skin autografts may be an alternative for the treatment of full-thickness wounds and wounds that cover large areas of the body surface. Autologous epidermal and dermal cells were isolated, expanded in vitro and seeded on collagen-elastin scaffolds. The developed autograft was immunohistochemically characterized and subsequently transplanted onto a facial chronic ulceration of a 71-year-old patient with vulnerable atrophic skin. Characterization of the skin equivalent revealed comparability to healthy human skin due to the epidermal strata, differentiation and proliferation markers. Within 138 days, the skin structure at the transplantation site closely correlated with the adjacent undisturbed skin. The present study demonstrates the comparability of the developed organotypic skin equivalent to healthy human skin and the versatility for clinical applications.

Tissue-Engineered Skin Substitute Enhances Wound Healing after Radiation Therapy.

Science.gov (United States)

Busra, Mohd Fauzi bin Mh; Chowdhury, Shiplu Roy; bin Ismail, Fuad; bin Saim, Aminuddin; Idrus, Ruszymah Bt Hj

2016-03-01

When given in conjunction with surgery for treating cancer, radiation therapy may result in impaired wound healing, which, in turn, could cause skin ulcers. In this study, bilayer and monolayer autologous skin substitutes were used to treat an irradiated wound. A single dose of 30 Gy of linear electron beam radiation was applied to the hind limb of nude mice before creating the skin lesion (area of 78.6 mm). Monolayer tissue-engineered skin substitutes (MTESSs) were prepared by entrapping cultured keratinocytes in fibrin matrix, and bilayer tissue-engineered skin substitutes (BTESSs) were prepared by entrapping keratinocytes and fibroblasts in separate layers. Bilayer tissue-engineered skin substitute and MTESS were implanted to the wound area. Gross appearance and wound area were analyzed to evaluate wound healing efficiency. Skin regeneration and morphological appearance were observed via histological and electron microscopy. Protein expressions of transforming growth factor β1 (TGF-β1), platelet-derived growth factor BB (PDGF-BB), and vascular endothelial growth factor (VEGF) in skin regeneration were evaluated by immunohistochemistry (IHC). Macroscopic observation revealed that at day 13, treatments with BTESS completely healed the irradiated wound, whereas wound sizes of 1.1 ± 0.05 and 6.8 ± 0.14 mm were measured in the MTESS-treated and untreated control groups, respectively. Hematoxylin-eosin (H&E) analysis showed formation of compact and organized epidermal and dermal layers in the BTESS-treated group, as compared with MTESS-treated and untreated control groups. Ultrastructural analysis indicates maturation of skin in BTESS-treated wound evidenced by formation of intermediate filament bundles in the dermal layer and low intercellular space in the epidermal layer. Expressions of TGF-β1, PDGF-BB, and VEGF were also higher in BTESS-treated wounds, compared with MTESS-treated wounds. These results indicate that BTESS is the preferred treatment for

Solar ultraviolet irradiation induces decorin degradation in human skin likely via neutrophil elastase.

Science.gov (United States)

Li, Yong; Xia, Wei; Liu, Ying; Remmer, Henriette A; Voorhees, John; Fisher, Gary J

2013-01-01

Exposure of human skin to solar ultraviolet (UV) irradiation induces matrix metalloproteinase-1 (MMP-1) activity, which degrades type I collagen fibrils. Type I collagen is the most abundant protein in skin and constitutes the majority of skin connective tissue (dermis). Degradation of collagen fibrils impairs the structure and function of skin that characterize skin aging. Decorin is the predominant proteoglycan in human dermis. In model systems, decorin binds to and protects type I collagen fibrils from proteolytic degradation by enzymes such as MMP-1. Little is known regarding alterations of decorin in response to UV irradiation. We found that solar-simulated UV irradiation of human skin in vivo stimulated substantial decorin degradation, with kinetics similar to infiltration of polymorphonuclear (PMN) cells. Proteases that were released from isolated PMN cells degraded decorin in vitro. A highly selective inhibitor of neutrophil elastase blocked decorin breakdown by proteases released from PMN cells. Furthermore, purified neutrophil elastase cleaved decorin in vitro and generated fragments with similar molecular weights as those resulting from protease activity released from PMN cells, and as observed in UV-irradiated human skin. Cleavage of decorin by neutrophil elastase significantly augmented fragmentation of type I collagen fibrils by MMP-1. Taken together, these data indicate that PMN cell proteases, especially neutrophil elastase, degrade decorin, and this degradation renders collagen fibrils more susceptible to MMP-1 cleavage. These data identify decorin degradation and neutrophil elastase as potential therapeutic targets for mitigating sun exposure-induced collagen fibril degradation in human skin.

The effect of pressure and shear on tissue viability of human skin in relation to the development of pressure ulcers: a systematic review.

Science.gov (United States)

Hoogendoorn, Iris; Reenalda, Jasper; Koopman, Bart F J M; Rietman, Johan S

2017-08-01

Pressure ulcers are a significant problem in health care, due to high costs and large impact on patients' life. In general, pressure ulcers develop as tissue viability decreases due to prolonged mechanical loading. The relation between load and tissue viability is highly influenced by individual characteristics. It is proposed that measurements of skin blood flow regulation could provide good assessment of the risk for pressure ulcer development, as skin blood flow is essential for tissue viability. . Therefore, the aim of this systematic review is to gain insight in the relation between mechanical load and the response of the skin and underlying tissue to this loading measured in-vivo with non-invasive techniques. A systematic literature search was performed to identify articles analysing the relation between mechanical load (pressure and/or shear) and tissue viability measured in-vivo. Two independent reviewers scored the methodological quality of the 22 included studies. Methodological information as well as tissue viability parameters during load application and after load removal were extracted from the included articles and used in a meta-analysis. Pressure results in a decrease in skin blood flow parameters, compared to baseline; showing a larger decrease with higher magnitudes of load. The steepness of the decrease is mostly dependent on the anatomical location. After load removal the magnitude of the post-reactive hyperaemic peak is related to the magnitude of pressure. Lastly, shear in addition to pressure, shows an additional negative effect, but the effect is less apparent than pressure on skin viability. Copyright © 2017 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

In-vitro percutaneous absorption of losartan potassium in human skin and prediction of human skin permeability

Directory of Open Access Journals (Sweden)

Petkar K.C.

2007-05-01

Full Text Available This study describes the feasibility of transdermal controlled administration of Losartan potassium (LP across human cadaver skin. Study also defines the influence of capsaicin, sex and site of application on permeation characteristics and determined an appropriate animal model for human skin permeability. The permeation of LP of various formulations was studied using Keshary-Chein diffusion cell. Optimized controlled formulation (without capsaicin released 42.17% (±1.85 of LP in 12 hr whereas treatment formulation (with capsaicin 0.028 % w/v released 48.94% (±1.71 of LP with significant difference on null hypothesis. Influence of sex showed statistically significant difference for permeation of LP through male and female rats, as well as male and female mice across both the abdominal and dorsal sides of the skin (p<0.05. Similarly statistically significant differences were noted for permeation of LP across male and female mice abdomen-dorsal, but not for male rat abdomen-dorsal and female rat abdomen-dorsal. Furthermore, in-vitro permeation of LP across human skin was compared with the permeation across rat and mice skins. Male rat and male mice dorsal skin was found to have closer permeability characteristics to human than other skin membranes, but the Factor of Difference values were < 3 for all membranes which were used suggesting the membranes are good models for human skin permeability. In conclusion simple transdermal adhesive patches formulations incorporating high molecular weight of LP can deliver a dose in-vivo and proposed model skin membranes can be utilized for future pharmacokineic and toxicokinetic studies as well as metabolism studies of LP

Diffuse Reflectance Spectroscopy of Human Skin Using a Commercial Fiber Optic Spectrometer

International Nuclear Information System (INIS)

Atencio, J. A. Delgado; Rodriguez, M. Cunill; Montiel, S. Vazquez y; Castro, Jorge; Rodriguez, A. Cornejo; Gutierrez, J. L.; Martinez, F.; Gutierrez, B.; Orozco, E.

2008-01-01

Diffuse reflectance spectroscopy is a reliable and easy to implement technique in human tissue characterization. In this work we evaluate the performance of the commercial USB4000 miniature fiber optic spectrometer in the in-vivo measurement of the diffuse reflectance spectra of different healthy skin sites and lesions in a population of 54 volunteers. Results show, that this spectrometer reproduces well the typical signatures of skin spectra over the 400-1000 nm region. Remarkable spectral differences exist between lesions and normal surrounding skin. A diffusion-based model was used to simulate reflectance spectra collected by the optical probe of the system

An ex vivo human skin model for studying skin barrier repair.

Science.gov (United States)

Danso, Mogbekeloluwa O; Berkers, Tineke; Mieremet, Arnout; Hausil, Farzia; Bouwstra, Joke A

2015-01-01

In the studies described in this study, we introduce a novel ex vivo human skin barrier repair model. To develop this, we removed the upper layer of the skin, the stratum corneum (SC) by a reproducible cyanoacrylate stripping technique. After stripping the explants, they were cultured in vitro to allow the regeneration of the SC. We selected two culture temperatures 32 °C and 37 °C and a period of either 4 or 8 days. After 8 days of culture, the explant generated SC at a similar thickness compared to native human SC. At 37 °C, the early and late epidermal differentiation programmes were executed comparably to native human skin with the exception of the barrier protein involucrin. At 32 °C, early differentiation was delayed, but the terminal differentiation proteins were expressed as in stripped explants cultured at 37 °C. Regarding the barrier properties, the SC lateral lipid organization was mainly hexagonal in the regenerated SC, whereas the lipids in native human SC adopt a more dense orthorhombic organization. In addition, the ceramide levels were higher in the cultured explants at 32 °C and 37 °C than in native human SC. In conclusion, we selected the stripped ex vivo skin model cultured at 37 °C as a candidate model to study skin barrier repair because epidermal and SC characteristics mimic more closely the native human skin than the ex vivo skin model cultured at 32 °C. Potentially, this model can be used for testing formulations for skin barrier repair. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cloud-based Monte Carlo modelling of BSSRDF for the rendering of human skin appearance (Conference Presentation)

Science.gov (United States)

Doronin, Alexander; Rushmeier, Holly E.; Meglinski, Igor; Bykov, Alexander V.

2016-03-01

We present a new Monte Carlo based approach for the modelling of Bidirectional Scattering-Surface Reflectance Distribution Function (BSSRDF) for accurate rendering of human skin appearance. The variations of both skin tissues structure and the major chromophores are taken into account correspondingly to the different ethnic and age groups. The computational solution utilizes HTML5, accelerated by the graphics processing units (GPUs), and therefore is convenient for the practical use at the most of modern computer-based devices and operating systems. The results of imitation of human skin reflectance spectra, corresponding skin colours and examples of 3D faces rendering are presented and compared with the results of phantom studies.

Evaluating low dose ionizing radiation effects on gene expression in human skin biopsy cores

International Nuclear Information System (INIS)

Goldberg, Z.; Schwietert, C.; Stern, R.L.; Lehnert, B.E.

2003-01-01

Significant biological effects can occur in animals, animal cells, immortalized human cell lines, and primary human cells after exposure to doses of ionizing radiation (IR) in the <1-10 cGy region. However it is unclear how these observations mimic or even pertain to the actual in vivo condition in humans, though such knowledge is required for reducing the uncertainty of assessing human risks due to low dose IR (LDIR) exposures. Further, low dose effects have increasing clinical relevance in the radiotherapeutic management of cancer as the volume of tissue receiving only LDIR increases as more targeted radiotherapy (i.e. IMRT) becomes more widely used. Thus, human translational data must be obtained with which to correlate in vitro experimental findings and evaluate their 'real-life' applicability. To evaluate LDIR effects in human tissue we have obtained freshly explanted full thickness human skin samples obtained from aesthetic surgery, and subjected them to ex vivo irradiation as a translational research model system of a complex human tissue. Ionizing radiation (IR) exposures were delivered at 1, 10, or 100 cGy. The temporal response to IR was assessed by harvesting RNA at multiple time points out to 24 hours post IR. Gene expression changes were assessed by real time PCR. We have shown that RNA can be reliably extracted with fidelity from 3 mm diameter punch biopsies of human tissue and provide good quality sample for the real time PCR evaluation. Genes of interest include those reported to have altered expression following LDIR from in vitro cell culture models. These include genes associated with cell cycle regulation, DNA repair and various cytokines. These feasibility studies in human skin irradiated ex vivo, have demonstrated that gene expression can be measured accurately from very small human tissue samples, thus setting the stage for biopsy acquisition of tissue irradiated in vivo from patients-volunteers. The clinical study has begun and the data from

Preservation and rapid purification of DNA from decomposing human tissue samples.

Science.gov (United States)

Sorensen, Amy; Rahman, Elizabeth; Canela, Cassandra; Gangitano, David; Hughes-Stamm, Sheree

2016-11-01

One of the key features to be considered in a mass disaster is victim identification. However, the recovery and identification of human remains are sometimes complicated by harsh environmental conditions, limited facilities, loss of electricity and lack of refrigeration. If human remains cannot be collected, stored, or identified immediately, bodies decompose and DNA degrades making genotyping more difficult and ultimately decreasing DNA profiling success. In order to prevent further DNA damage and degradation after collection, tissue preservatives may be used. The goal of this study was to evaluate three customized (modified TENT, DESS, LST) and two commercial DNA preservatives (RNAlater and DNAgard ® ) on fresh and decomposed human skin and muscle samples stored in hot (35°C) and humid (60-70% relative humidity) conditions for up to three months. Skin and muscle samples were harvested from the thigh of three human cadavers placed outdoors for up to two weeks. In addition, the possibility of purifying DNA directly from the preservative solutions ("free DNA") was investigated in order to eliminate lengthy tissue digestion processes and increase throughput. The efficiency of each preservative was evaluated based on the quantity of DNA recovered from both the "free DNA" in solution and the tissue sample itself in conjunction with the quality and completeness of downstream STR profiles. As expected, DNA quantity and STR success decreased with time of decomposition. However, a marked decrease in DNA quantity and STR quality was observed in all samples after the bodies entered the bloat stage (approximately six days of decomposition in this study). Similar amounts of DNA were retrieved from skin and muscle samples over time, but slightly more complete STR profiles were obtained from muscle tissue. Although higher amounts of DNA were recovered from tissue samples than from the surrounding preservative, the average number of reportable alleles from the "free DNA" was

Discrimination between basal cell carcinoma and hair follicles in skin tissue sections by Raman micro-spectroscopy

Science.gov (United States)

Larraona-Puy, M.; Ghita, A.; Zoladek, A.; Perkins, W.; Varma, S.; Leach, I. H.; Koloydenko, A. A.; Williams, H.; Notingher, I.

2011-05-01

Skin cancer is the most common human malignancy and basal cell carcinoma (BCC) represents approximately 80% of the non-melanoma cases. Current methods of treatment require histopathological evaluation of the tissues by qualified personnel. However, this method is subjective and in some cases BCC can be confused with other structures in healthy skin, including hair follicles. In this preliminary study, we investigated the potential of Raman micro-spectroscopy (RMS) to discriminate between hair follicles and BCC in skin tissue sections excised during Mohs micrographic surgery (MMS). Imaging and diagnosis of skin sections was automatically generated using ' a priori'-built spectral model based on LDA. This model had 90 ± 9% sensitivity and 85 ± 9% specificity for discrimination of BCC from dermis and epidermis. The model used selected Raman bands corresponding to the largest spectral differences between the Raman spectra of BCC and the normal skin regions, associated mainly with nucleic acids and collagen type I. Raman spectra corresponding to the epidermis regions of the hair follicles were found to be closer to those of healthy epidermis rather than BCC. Comparison between Raman spectral images and the gold standard haematoxylin and eosin (H&E) histopathology diagnosis showed good agreement. Some hair follicle regions were misclassified as BCC; regions corresponded mainly to the outermost layer of hair follicle (basal cells) which are expected to have higher nucleic acid concentration. This preliminary study shows the ability of RMS to distinguish between BCC and other tissue structures associated to healthy skin which can be confused with BCC due to their similar morphology.

Isthmin 1 Is a Secreted Protein Expressed in Skin, Mucosal Tissues, and NK, NKT, and Th17 Cells

OpenAIRE

Valle-Rios, Ricardo; Maravillas-Montero, José L.; Burkhardt, Amanda M.; Martinez, Cynthia; Buhren, Bettina Alexandra; Homey, Bernhard; Gerber, Peter Arne; Robinson, Octavio; Hevezi, Peter; Zlotnik, Albert

2014-01-01

Using a comprehensive microarray database of human gene expression, we identified that in mammals, a secreted protein known as isthmin 1 (ISM1) is expressed in skin, mucosal tissues, and selected lymphocyte populations. ISM1 was originally identified in Xenopus brain during development, and it encodes a predicted ∼50-kDa protein containing a signal peptide, a thrombospondin domain, and an adhesion-associated domain. We confirmed the pattern of expression of ISM1 in both human and mouse tissue...

Novel Tissue Models of Junctional Epidermolysis Bullosa to Characterize Functional Mechanisms of Sulfur Mustard Injury to Human Skin

National Research Council Canada - National Science Library

Garlick, Joanthan

2003-01-01

In the second year of our research, our laboratory has extensively studied skin pathophysiology in response to SM by adapting in vivo, human skin/nude mouse chimera to further understand mechanisms...

Point-of-care instrument for monitoring tissue health during skin graft repair

Science.gov (United States)

Gurjar, R. S.; Seetamraju, M.; Zhang, J.; Feinberg, S. E.; Wolf, D. E.

2011-06-01

We have developed the necessary theoretical framework and the basic instrumental design parameters to enable mapping of subsurface blood dynamics and tissue oxygenation for patients undergoing skin graft procedures. This analysis forms the basis for developing a simple patch geometry, which can be used to map by diffuse optical techniques blood flow velocity and tissue oxygenation as a function of depth in subsurface tissue.skin graft, diffuse correlation analysis, oxygen saturation.

Low-intensity infrared lasers alter actin gene expression in skin and muscle tissue

International Nuclear Information System (INIS)

Fonseca, A S; Mencalha, A L; Campos, V M A; Ferreira-Machado, S C; Peregrino, A A F; Magalhães, L A G; Geller, M; Paoli, F

2013-01-01

The biostimulative effect of low-intensity lasers is the basis for treatment of diseases in soft tissues. However, data about the influence of biostimulative lasers on gene expression are still scarce. The aim of this work was to evaluate the effects of low-intensity infrared lasers on the expression of actin mRNA in skin and muscle tissue. Skin and muscle tissue of Wistar rats was exposed to low-intensity infrared laser radiation at different fluences and frequencies. One and 24 hours after laser exposure, tissue samples were withdrawn for total RNA extraction, cDNA synthesis and evaluation of actin gene expression by quantitative polymerase chain reaction. The data obtained show that laser radiation alters the expression of actin mRNA differently in skin and muscle tissue of Wistar rats depending of the fluence, frequency and time after exposure. The results could be useful for laser dosimetry, as well as to justify the therapeutic protocols for treatment of diseases of skin and muscle tissues based on low-intensity infrared laser radiation. (paper)

First donation of human skin obtained from corpse; Primera donacion de piel humana obtenida de cadaver

Energy Technology Data Exchange (ETDEWEB)

Reyes F, M L; Luna Z, D [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

2007-07-01

The first donation of human skin coming from a cadaverous donor was obtained in the State of Mexico. The skin was obtained of a 34 year-old multi organic donor, the extraction of the same was carried out in an operating theatre by medical personnel, supported by personal of the Radio sterilized Tissue Bank (BTR) of the ININ. The skin was transported to the BTR for it processing. (Author)

Histological and Ultrastructural Effects of Ultrasound-induced Cavitation on Human Skin Adipose Tissue.

Science.gov (United States)

Bani, Daniele; Quattrini Li, Alessandro; Freschi, Giancarlo; Russo, Giulia Lo

2013-09-01

In aesthetic medicine, the most promising techniques for noninvasive body sculpturing purposes are based on ultrasound-induced fat cavitation. Liporeductive ultrasound devices afford clinically relevant subcutaneous fat pad reduction without significant adverse reactions. This study aims at evaluating the histological and ultrastructural changes induced by ultrasound cavitation on the different cell components of human skin. Control and ultrasound-treated ex vivo abdominal full-thickness skin samples and skin biopsies from patients pretreated with or without ultrasound cavitation were studied histologically, morphometrically, and ultrastructurally to evaluate possible changes in adipocyte size and morphology. Adipocyte apoptosis and triglyceride release were also assayed. Clinical evaluation of the effects of 4 weekly ultrasound vs sham treatments was performed by plicometry. Compared with the sham-treated control samples, ultrasound cavitation induced a statistically significant reduction in the size of the adipocytes (P ultrasound treatment caused a significant reduction of abdominal fat. This study further strengthens the current notion that noninvasive transcutaneous ultrasound cavitation is a promising and safe technology for localized reduction of fat and provides experimental evidence for its specific mechanism of action on the adipocytes.

Comparison of the antiseptic efficacy of tissue-tolerable plasma and an octenidine hydrochloride-based wound antiseptic on human skin.

Science.gov (United States)

Lademann, J; Richter, H; Schanzer, S; Patzelt, A; Thiede, G; Kramer, A; Weltmann, K-D; Hartmann, B; Lange-Asschenfeldt, B

2012-01-01

Colonization and infection of wounds represent a major reason for the impairment of tissue repair. Recently, it has been reported that tissue-tolerable plasma (TTP) is highly efficient in the reduction of the bacterial load of the skin. In the present study, the antiseptic efficacy of TTP was compared to that of octenidine hydrochloride with 2-phenoxyethanol. Both antiseptic methods proved to be highly efficient. Cutaneous treatment of the skin with octenidine hydrochloride and 2-phenoxyethanol leads to a 99% elimination of the bacteria, and 74% elimination is achieved by TTP treatment. Technical challenges with an early prototype TTP device could be held responsible for the slightly reduced antiseptic properties of TTP, compared to a standard antiseptic solution, since the manual treatment of the skin surface with a small beam of the TTP device might have led to an incomplete coverage of the treated area. Copyright © 2012 S. Karger AG, Basel.

Melanin Transfer in Human 3D Skin Equivalents Generated Exclusively from Induced Pluripotent Stem Cells.

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Gledhill, Karl; Guo, Zongyou; Umegaki-Arao, Noriko; Higgins, Claire A; Itoh, Munenari; Christiano, Angela M

2015-01-01

The current utility of 3D skin equivalents is limited by the fact that existing models fail to recapitulate the cellular complexity of human skin. They often contain few cell types and no appendages, in part because many cells found in the skin are difficult to isolate from intact tissue and cannot be expanded in culture. Induced pluripotent stem cells (iPSCs) present an avenue by which we can overcome this issue due to their ability to be differentiated into multiple cell types in the body and their unlimited growth potential. We previously reported generation of the first human 3D skin equivalents from iPSC-derived fibroblasts and iPSC-derived keratinocytes, demonstrating that iPSCs can provide a foundation for modeling a complex human organ such as skin. Here, we have increased the complexity of this model by including additional iPSC-derived melanocytes. Epidermal melanocytes, which are largely responsible for skin pigmentation, represent the second most numerous cell type found in normal human epidermis and as such represent a logical next addition. We report efficient melanin production from iPSC-derived melanocytes and transfer within an entirely iPSC-derived epidermal-melanin unit and generation of the first functional human 3D skin equivalents made from iPSC-derived fibroblasts, keratinocytes and melanocytes.

Melanin Transfer in Human 3D Skin Equivalents Generated Exclusively from Induced Pluripotent Stem Cells.

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Karl Gledhill

Full Text Available The current utility of 3D skin equivalents is limited by the fact that existing models fail to recapitulate the cellular complexity of human skin. They often contain few cell types and no appendages, in part because many cells found in the skin are difficult to isolate from intact tissue and cannot be expanded in culture. Induced pluripotent stem cells (iPSCs present an avenue by which we can overcome this issue due to their ability to be differentiated into multiple cell types in the body and their unlimited growth potential. We previously reported generation of the first human 3D skin equivalents from iPSC-derived fibroblasts and iPSC-derived keratinocytes, demonstrating that iPSCs can provide a foundation for modeling a complex human organ such as skin. Here, we have increased the complexity of this model by including additional iPSC-derived melanocytes. Epidermal melanocytes, which are largely responsible for skin pigmentation, represent the second most numerous cell type found in normal human epidermis and as such represent a logical next addition. We report efficient melanin production from iPSC-derived melanocytes and transfer within an entirely iPSC-derived epidermal-melanin unit and generation of the first functional human 3D skin equivalents made from iPSC-derived fibroblasts, keratinocytes and melanocytes.

Human Adipose Mesenchymal Cells Inhibit Melanocyte Differentiation and the Pigmentation of Human Skin via Increased Expression of TGF-β1.

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Klar, Agnes S; Biedermann, Thomas; Michalak, Katarzyna; Michalczyk, Teresa; Meuli-Simmen, Claudia; Scherberich, Arnaud; Meuli, Martin; Reichmann, Ernst

2017-12-01

There is accumulating evidence that interactions between epidermal melanocytes and stromal cells play an important role in the regulation of skin pigmentation. In this study we established a pigmented dermo-epidermal skin model, melDESS, of human origin to investigate the effects of distinct stromal cells on melanogenesis. melDESS is a complex, clinically relevant skin equivalent composed of an epidermis containing both melanocytes and keratinocytes. Its dermal compartment consists either of adipose tissue-derived stromal cells, dermal fibroblasts (Fbs), or a mixture of both cell types. These skin substitutes were transplanted for 5 weeks on the backs of immuno-incompetent rats and analyzed. Gene expression and Western blot analyses showed a significantly higher expression of transforming growth factor-β1 by adipose tissue-derived stromal cells compared with dermal Fbs. In addition, we showed that melanocytes responded to the increased levels of transforming growth factor-β1 by down-regulating the expression of key melanogenic enzymes such as tyrosinase. This caused decreased melanin synthesis and, consequently, greatly reduced pigmentation of melDESS. The conclusions are of utmost clinical relevance, namely that adipose tissue-derived stromal cells derived from the hypodermis fail to appropriately interact with epidermal melanocytes, thus preventing the sustainable restoration of the patient's native skin color in bioengineered skin grafts. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Three-dimensional digital reconstruction of skin epidermis and dermis.

Science.gov (United States)

Liu, P; Zhu, J-Y; Tang, B; Hu, Z-C

2018-05-01

This study describes how three-dimensional (3D) human skin tissue is reconstructed, and provides digital anatomical data for the physiological structure of human skin tissue based on large-scale thin serial sections. Human skin samples embedded in paraffin were cut serially into thin sections and then stained with hematoxylin-eosin. Images of serial sections obtained from lighting microscopy were scanned and aligned by the scale-invariant feature transform algorithm. 3D reconstruction of the skin tissue was generated using Mimics software. Fibre content, porosity, average pore diameter and specific surface area of dermis were analysed using the ImageJ analysis system. The root mean square error and mutual information based on the scale-invariant feature transform algorithm registration were significantly greater than those based on the manual registration. Fibre distribution gradually decreased from top to bottom; while porosity showed an opposite trend with irregular average pore diameter distribution. A specific surface area of the dermis showed a 'V' shape trend. Our data suggested that 3D reconstruction of human skin tissue based on large-scale serial sections could be a valuable tool for providing a highly accurate histological structure for analysis of skin tissue. Moreover, this technology could be utilized to produce tissue-engineered skin via a 3D bioprinter in the future. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Antibiotic susceptibility pattern and the prevalence of Staphylococcus aureus isolated from skin and soft tissue in Tehran Razi skin hospital (2014-15

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Zeynab Fagheei-Aghmiyuni

2017-06-01

Full Text Available Background: Staphylococcus aureus (S. aureus is the most common cause of skin and soft tissue infections. This study aimed to determine the prevalence of S. aureus isolated from skin and soft tissue and antibiotic susceptibility pattern among the patient hospitalized in Razi skin hospital (Tehran-Iran. Materials and Methods: This cross-sectional study was conducted on patients (n=400 with skin and soft tissue infections in Razi skin hospital. Sterilized swabs were used to collect the skin infection samples. S. aureus isolates were confirmed using biochemical tests (gram staining, catalase, coagulase, DNase test and manitol fermentation tests. Result: 51.3 %( 205 out of 400 of isolates were S. aureus. Ninety six (46.8% of isolates were methicillin and penicillin-resistant S. aureus. All of the isolates showed sensitivity to vancomycin, linezolid. 98% of the isolates were susceptible to daptomycin. One-hundred sixteen (56.6% isolates were multi- drug resistant. Conclusion: More than half of the skin and soft tissue infections were caused by S.aureus. More than 46 percent of the isolates were methicillin resistant. The highest resistance to penicillin was observed.

Robust Lentiviral Gene Delivery But Limited Transduction Capacity of Commonly Used Adeno-Associated Viral Serotypes in Xenotransplanted Human Skin.

Science.gov (United States)

Jakobsen, Maria; Askou, Anne Louise; Stenderup, Karin; Rosada, Cecilia; Dagnæs-Hansen, Frederik; Jensen, Thomas G; Corydon, Thomas J; Mikkelsen, Jacob Giehm; Aagaard, Lars

2015-08-01

Skin is an easily accessible organ, and therapeutic gene transfer to skin remains an attractive alternative for the treatment of skin diseases. Although we have previously documented potent lentiviral gene delivery to human skin, vectors based on adeno-associated virus (AAV) rank among the most promising gene delivery tools for in vivo purposes. Thus, we compared the potential usefulness of various serotypes of recombinant AAV vectors and lentiviral vectors for gene transfer to human skin in a xenotransplanted mouse model. Vector constructs encoding firefly luciferase were packaged in AAV capsids of serotype 1, 2, 5, 6, 8, and 9 and separately administered by intradermal injection in human skin transplants. For all serotypes, live bioimaging demonstrated low levels of transgene expression in the human skin graft, and firefly luciferase expression was observed primarily in neighboring tissue outside of the graft. In contrast, gene delivery by intradermally injected lentiviral vectors was efficient and led to extensive and persistent firefly luciferase expression within the human skin graft only. The study demonstrates the limited capacity of single-stranded AAV vectors of six commonly used serotypes for gene delivery to human skin in vivo.

Wave propagation as a marker of structural and topographic properties of human skin

Science.gov (United States)

Djaghloul, M.; Abdouni, A.; Thieulin, C.; Zahouani, H.

2018-06-01

Chronological skin ageing is a phenomenon which imposes structural and functional changes on the cutaneous tissue. Mechanically, these changes can be related to structural rearrangements of the cutaneous tissue on surface and in volume (layers thickness). At the micro-structural level, the constitutional elements of the skin, collagen and elastin fibres, undergo also this rearrangement. The evolution of skin’s mechanical properties at this level is the origin of a primordial in-vivo mechanical characteristic known as the natural pretension. In the context of understanding the in-vivo skin mechanical behaviour, related to the natural pretension, a lot of instrumentations have been demonstrated in the literature. They are mainly based on the interaction between dynamic adapted solicitation and the observed reaction on the skin. In this study, we evaluate the mechanical behaviour of human skin, following an impact which induces wave propagation. The use of impact solicitation allows the direct correlation between the dynamic induced reaction (vibration, and wave propagation) of the cutaneous tissue and its mechanical property. In our development, impact solicitation is contactless, with an air blast as generator of local deformation. The estimation of the speed of wave propagation enables the characterization of the mechanical behaviour of the skin. In order to validate the developed approaches, to understand the chronological ageing, gender and anisotropy effects on the skin properties, measurements have been realized on 77 healthy volunteers separated in five age groups. The obtained results are consistent with earlier works and confirm the efficiency of the developed instrumentation to estimate the changes of mechanical behaviour of the skin under age and gender effects.

Under Persistent Assault: Understanding the Factors that Deteriorate Human Skin and Clinical Efficacy of Topical Antioxidants in Treating Aging Skin

Directory of Open Access Journals (Sweden)

Patricia K. Farris

2015-11-01

Full Text Available Recent studies contend that the skin is subject to far more damage than just ultraviolet (UV light, with infrared radiation and pollution now clearly demonstrated to degrade cutaneous tissue. While consumers continue to strive for new ways to augment the aesthetic appeal and improve the health of their skin, awareness regarding environmental insults and effective ways to protect the skin remains low. New advances in dermatologic science have exponentially increased the available information on the underlying mechanism of cutaneous damage and potential of topical antioxidants to treat aging skin. Combining antioxidants that can work through multiple pathways holds great potential for a cumulative and synergistic way to treat aging skin. Our goal is to provide a comprehensive review on environmental factors that damage human skin, discuss scientifically proven benefits of topical antioxidants, understand challenges of formulating and administering topical antioxidants, evaluate novel mechanisms of antioxidant activity, and suggest practical ways of integrating topical antioxidants with aesthetic procedures to complement clinical outcomes.

Reconstruction of living bilayer human skin equivalent utilizing human fibrin as a scaffold.

Science.gov (United States)

Mazlyzam, A L; Aminuddin, B S; Fuzina, N H; Norhayati, M M; Fauziah, O; Isa, M R; Saim, L; Ruszymah, B H I

2007-05-01

Our aim of this study was to develop a new methodology for constructing a bilayer human skin equivalent to create a more clinical compliance skin graft composite for the treatment of various skin defects. We utilized human plasma derived fibrin as the scaffold for the development of a living bilayer human skin equivalent: fibrin-fibroblast and fibrin-keratinocyte (B-FF/FK SE). Skin cells from six consented patients were culture-expanded to passage 1. For B-FF/FK SE formation, human fibroblasts were embedded in human fibrin matrix and subsequently another layer of human keratinocytes in human fibrin matrix was stacked on top. The B-FF/FK SE was then transplanted to athymic mice model for 4 weeks to evaluate its regeneration and clinical performance. The in vivo B-FF/FK SE has similar properties as native human skin by histological analysis and expression of basal Keratin 14 gene in the epidermal layer and Collagen type I gene in the dermal layer. Electron microscopy analysis of in vivo B-FF/FK SE showed well-formed and continuous epidermal-dermal junction. We have successfully developed a technique to engineer living bilayer human skin equivalent using human fibrin matrix. The utilization of culture-expanded human skin cells and fibrin matrix from human blood will allow a fully autologous human skin equivalent construction.

Fish collagen/alginate/chitooligosaccharides integrated scaffold for skin tissue regeneration application.

Science.gov (United States)

Chandika, Pathum; Ko, Seok-Chun; Oh, Gun-Woo; Heo, Seong-Yeong; Nguyen, Van-Tinh; Jeon, You-Jin; Lee, Bonggi; Jang, Chul Ho; Kim, GeunHyung; Park, Won Sun; Chang, Wonseok; Choi, Il-Whan; Jung, Won-Kyo

2015-11-01

An emerging paradigm in wound healing techniques is that a tissue-engineered skin substitute offers an alternative approach to create functional skin tissue. Here we developed a fish collagen/alginate (FCA) sponge scaffold that was functionalized by different molecular weights of chitooligosaccharides (COSs) with the use of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride as a cross-linking agent. The effects of cross-linking were analyzed by Fourier transform infrared spectroscopy. The results indicate that the homogeneous materials blending and cross-linking intensity were dependent on the molecular weights of COSs. The highly interconnected porous architecture with 160-260μm pore size and over 90% porosity and COS's MW driven swelling and retention capacity, tensile property and in vitro biodegradation behavior guaranteed the FCA/COS scaffolds for skin tissue engineering application. Further improvement of these properties enhanced the cytocompatibility of all the scaffolds, especially the scaffolds containing COSs with MW in the range of 1-3kDa (FCA/COS1) showed the best cytocompatibility. These physicochemical, mechanical, and biological properties suggest that the FCA/COS1 scaffold is a superior candidate that can be used for skin tissue regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Large-scale expansion of human skin-derived precursor cells (hSKPs) in stirred suspension bioreactors.

Science.gov (United States)

Surrao, Denver C; Boon, Kathryn; Borys, Breanna; Sinha, Sarthak; Kumar, Ranjan; Biernaskie, Jeff; Kallos, Michael S

2016-12-01

Human skin-derived precursor cells (hSKPs) are multipotent adult stem cells found in the dermis of human skin. Incorporation of hSKPs into split-thickness skin grafts (STSGs), the current gold standard to treat severe burns or tissue resections, has been proposed as a treatment option to enhance skin wound healing and tissue function. For this approach to be clinically viable substantial quantities of hSKPs are required, which is the rate-limiting step, as only a few thousand hSKPs can be isolated from an autologous skin biopsy without causing donor site morbidity. In order to produce sufficient quantities of clinically viable cells, we have developed a bioprocess capable of expanding hSKPs as aggregates in stirred suspension bioreactors (SSBs). In this study, we found hSKPs from adult donors to expand significantly more (P skin biopsy without causing donor site morbidity. At 60 rpm, aggregates were markedly smaller and did not experience oxygen diffusional limitations, as seen in hSKPs cultured at 40 rpm. While hSKPs also grew at 80 rpm (0.74 Pa) and 100 rpm (1 Pa), they produced smaller aggregates due to high shear stress. The pH of the media in all the SSBs was closer to biological conditions and significantly different (P skin wounds. Biotechnol. Bioeng. 2016;113: 2725-2738. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Tumors of the skin and soft tissues

Energy Technology Data Exchange (ETDEWEB)

Weller, R.E.

1991-10-01

The majority of the body surface is covered by the skin. Many internal disorders are reflected in the condition of the skin. One of the major functions of the skin is protection of the other organ systems from a variety of environmental insults. In this role, the skin itself is exposed to factors that can ultimately cause chronic diseases and cancer. Since it is relatively easy to recognize skin abnormalities, most skin cancers are brought to professional attention sooner than other types of cancer. However, due to the close resemblance between many skin neoplasms and noncancerous dermatologic disorders, these neoplasms may be mistreated for months or even years. In veterinary oncology, as in human medicine, most cancers can be effectively treated or cured following an accurate diagnosis. Once diagnosed, skin neoplasms should be aggressively treated. If causal factors are known, exposure to these factors should be limited through removal of the agent (for chemical carcinogens) or limiting exposure to the agent (for other carcinogens such as sunlight). 10 tabs. (MHB)

Tissue expansion and fluid absorption by skin tissue following intradermal injections through hollow microneedles

Science.gov (United States)

Shrestha, Pranav; Stoeber, Boris

2017-11-01

Hollow microneedles provide a promising alternative to conventional drug delivery techniques due to improved patient compliance and the dose sparing effect. The dynamics of fluid injected through hollow microneedles into skin, which is a heterogeneous and deformable porous medium, have not been investigated extensively in the past. We have introduced the use of Optical Coherence Tomography (OCT) for real-time visualization of fluid injections into excised porcine tissue. The results from ex-vivo experiments, including cross-sectional tissue images from OCT and pressure/flow-rate measurements, show a transient mode of high flow-rate into the tissue followed by a lower steady-state infusion rate. The injected fluid expands the underlying tissue and causes the external free surface of the skin to rise, forming a characteristic intradermal wheal. We have used OCT to visualize the evolution of tissue and free surface deformation, and advancement of the boundary between regions of expanding and stationary tissue. We will show the effect of different injection parameters such as fluid pressure, viscosity and microneedle retraction on the injected volume. This work has been supported through funding from the Collaborative Health Research Program by the Natural Science and Engineering Research Council of Canada and the Canadian Health Research Institute, and through the Canada Research Chairs program.

Supraclavicular skin temperature as a measure of 18F-FDG uptake by BAT in human subjects.

Science.gov (United States)

Boon, Mariëtte R; Bakker, Leontine E H; van der Linden, Rianne A D; Pereira Arias-Bouda, Lenka; Smit, Frits; Verberne, Hein J; van Marken Lichtenbelt, Wouter D; Jazet, Ingrid M; Rensen, Patrick C N

2014-01-01

Brown adipose tissue (BAT) has emerged as a novel player in energy homeostasis in humans and is considered a potential new target for combating obesity and related diseases. The current 'gold standard' for quantification of BAT volume and activity is cold-induced 18F-FDG uptake in BAT. However, use of this technique is limited by cost and radiation exposure. Given the fact that BAT is a thermogenic tissue, mainly located in the supraclavicular region, the aim of the current study was to investigate whether cold-induced supraclavicular skin temperature and core body temperature may be alternative markers of BAT activation in humans. BAT volume and activity were measured in 24 healthy lean adolescent males (mean age 24.1±0.8 years), using cold-induced 18F-FDG uptake with PET-CT. Core body temperature was measured continuously in the small intestine with use of an ingestible telemetric capsule and skin temperature was measured by eighteen wireless iButtons attached to the skin following ISO-defined locations. Proximal and distal (hand/feet) skin temperatures markedly decreased upon cold exposure, while supraclavicular skin temperature significantly increased (35.2±0.1 vs. 35.5±0.1°C, p = 0.001). Furthermore, cold-induced supraclavicular skin temperature positively correlated with both total (R2 = 0.28, P = 0.010) and clavicular BAT volume (R2 = 0.20, P = 0.030) and clavicular SUVmax (R2 = 0.27, P = 0.010), while core body temperature did not. Supraclavicular skin temperature as measured by iButtons may have predictive value for BAT detection in adult humans. This is highly desirable considering the increasing interest in pharmacological interventions to stimulate BAT in human subjects. NTR 2473.

Gene expression changes with age in skin, adipose tissue, blood and brain.

Science.gov (United States)

Glass, Daniel; Viñuela, Ana; Davies, Matthew N; Ramasamy, Adaikalavan; Parts, Leopold; Knowles, David; Brown, Andrew A; Hedman, Asa K; Small, Kerrin S; Buil, Alfonso; Grundberg, Elin; Nica, Alexandra C; Di Meglio, Paola; Nestle, Frank O; Ryten, Mina; Durbin, Richard; McCarthy, Mark I; Deloukas, Panagiotis; Dermitzakis, Emmanouil T; Weale, Michael E; Bataille, Veronique; Spector, Tim D

2013-07-26

Previous studies have demonstrated that gene expression levels change with age. These changes are hypothesized to influence the aging rate of an individual. We analyzed gene expression changes with age in abdominal skin, subcutaneous adipose tissue and lymphoblastoid cell lines in 856 female twins in the age range of 39-85 years. Additionally, we investigated genotypic variants involved in genotype-by-age interactions to understand how the genomic regulation of gene expression alters with age. Using a linear mixed model, differential expression with age was identified in 1,672 genes in skin and 188 genes in adipose tissue. Only two genes expressed in lymphoblastoid cell lines showed significant changes with age. Genes significantly regulated by age were compared with expression profiles in 10 brain regions from 100 postmortem brains aged 16 to 83 years. We identified only one age-related gene common to the three tissues. There were 12 genes that showed differential expression with age in both skin and brain tissue and three common to adipose and brain tissues. Skin showed the most age-related gene expression changes of all the tissues investigated, with many of the genes being previously implicated in fatty acid metabolism, mitochondrial activity, cancer and splicing. A significant proportion of age-related changes in gene expression appear to be tissue-specific with only a few genes sharing an age effect in expression across tissues. More research is needed to improve our understanding of the genetic influences on aging and the relationship with age-related diseases.

Evaluation of 3D-human skin equivalents for assessment of human dermal absorption of some brominated flame retardants.

Science.gov (United States)

Abdallah, Mohamed Abou-Elwafa; Pawar, Gopal; Harrad, Stuart

2015-11-01

Ethical and technical difficulties inherent to studies in human tissues are impeding assessment of the dermal bioavailability of brominated flame retardants (BFRs). This is further complicated by increasing restrictions on the use of animals in toxicity testing, and the uncertainties associated with extrapolating data from animal studies to humans due to inter-species variations. To overcome these difficulties, we evaluate 3D-human skin equivalents (3D-HSE) as a novel in vitro alternative to human and animal testing for assessment of dermal absorption of BFRs. The percutaneous penetration of hexabromocyclododecanes (HBCD) and tetrabromobisphenol-A (TBBP-A) through two commercially available 3D-HSE models was studied and compared to data obtained for human ex vivo skin according to a standard protocol. No statistically significant differences were observed between the results obtained using 3D-HSE and human ex vivo skin at two exposure levels. The absorbed dose was low (less than 7%) and was significantly correlated with log Kow of the tested BFR. Permeability coefficient values showed increasing dermal resistance to the penetration of γ-HBCD>β-HBCD>α-HBCD>TBBPA. The estimated long lag times (>30 min) suggests that frequent hand washing may reduce human exposure to HBCDs and TBBPA via dermal contact. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermal analysis of epidermal electronic devices integrated with human skin considering the effects of interfacial thermal resistance

Science.gov (United States)

Li, Yuhang; Zhang, Jianpeng; Xing, Yufeng; Song, Jizhou

2018-05-01

Epidermal electronic devices (EEDs) have similar mechanical properties as those of human skin such that they can be integrated with human skin for potential applications in monitoring of human vital signs for diagnostic, therapeutic or surgical functions. Thermal management is critical for EEDs in these applications since excessive heating may cause discomfort. Comprehensive analytical studies, finite element analysis and experiments are carried out to study the effects of interfacial thermal resistance between EEDs and human skin on thermal properties of the EED/skin system in this paper. The coupling between the Fourier heat transfer in EEDs and the bio-heat transfer in human skin is accounted in the analytical model based on the transfer matrix method to give accurate predictions on temperatures, which agree well with finite element analysis and experimental measurements. It is shown that the maximum temperature increase of the EED for the case of imperfect bonding between EED and skin is much higher than that of perfect bonding. These results may help the design of EEDs in bi-integrated applications and suggest a valuable route to evaluate the bonding condition between EEDs and biological tissues.

Colony size distributions according to in vitro aging in human skin fibroblasts

International Nuclear Information System (INIS)

Kim, Jun Sang; Kim, Jae Sung; Cho, Moon June; Park, Jeong Kyu; Paik, Tae Hyun

1999-01-01

To investigate the percentage of colonies with 16 or more cells distribution of human skin fibroblast according to in vitro aging, and to evaluate the relationship between percentage of colonies with 16 or more cells and in vivo donor age in human skin fibroblast culture. C1, C2, C3a, and C3b human skin fibroblast samples from three breast cancer patients were used as subjects. The C1, C2, and C3a donor were 44, 54, and 55 years old, respectively. C3a and C3b cells were isolated from the same person. Single cell suspension of skin fibroblasts was prepared with primary explant technique. One hundred cells are plated into 100ml tissue culture flask and cultured for two weeks. The colony size was defined as colonies with 16 or more cells. The cultured cell was stained with crystal violet, and number of cells in each colony was determined with stereo microscope at x 10 magnification. Passage number of C1, C2, C3a and C3b skin fibroblast were 12th, 17th, and 14th, respectively. Percentage of colonies with 16 or more cells of skin fibroblast samples decreased with increasing in vitro passage number. In contrast, cumulative population doublings of skin fibroblast sample increased with increasing in vitro passage number. Percentage of colonies with 16 or more cells also decreased with increasing population doublings in human skin fibroblast culture. There was strong correlation with percentage of colonised with 16 or more cells and population doublings in C3a skin fibroblast sample. At the same point of population doublings, the percentage of colonies with 16 or more cells of the young C1 donor was higher level than the old C3a donor. The population doublings increased with increasing in vitro passage number but percentage of colonies with 16 or more cells decreased. The results of this study imply that percentage of colonies with 16 or more cells is useful as a indicator of in vitro human skin fibroblast aging and may estimate the in vivo donor age

Ultrathin conformal devices for precise and continuous thermal characterization of human skin

Science.gov (United States)

Webb, R. Chad; Bonifas, Andrew P.; Behnaz, Alex; Zhang, Yihui; Yu, Ki Jun; Cheng, Huanyu; Shi, Mingxing; Bian, Zuguang; Liu, Zhuangjian; Kim, Yun-Soung; Yeo, Woon-Hong; Park, Jae Suk; Song, Jizhou; Li, Yuhang; Huang, Yonggang; Gorbach, Alexander M.; Rogers, John A.

2013-10-01

Precision thermometry of the skin can, together with other measurements, provide clinically relevant information about cardiovascular health, cognitive state, malignancy and many other important aspects of human physiology. Here, we introduce an ultrathin, compliant skin-like sensor/actuator technology that can pliably laminate onto the epidermis to provide continuous, accurate thermal characterizations that are unavailable with other methods. Examples include non-invasive spatial mapping of skin temperature with millikelvin precision, and simultaneous quantitative assessment of tissue thermal conductivity. Such devices can also be implemented in ways that reveal the time-dynamic influence of blood flow and perfusion on these properties. Experimental and theoretical studies establish the underlying principles of operation, and define engineering guidelines for device design. Evaluation of subtle variations in skin temperature associated with mental activity, physical stimulation and vasoconstriction/dilation along with accurate determination of skin hydration through measurements of thermal conductivity represent some important operational examples.

Storage Conditions of Skin Affect Tissue Structure and Subsequent in vitro Percutaneous Penetration

DEFF Research Database (Denmark)

Nielsen, Jesper Bo; Plasencia Gil, Maria Inés; Sørensen, Jens Ahm

2011-01-01

fluorescence microscopy) and in vitro percutaneous penetration of caffeine under four different storage conditions using skin samples from the same donors: fresh skin, skin kept at -20°C for 3 weeks (with or without the use of polyethylene glycol) and at -80°C. Our results show a correlation between increasing...... permeation of caffeine and tissue structural damage caused by the storage conditions, most so after skin storage at -80°C. The presented approach, which combines imaging techniques with studies on percutaneous penetration, enables the link between tissue damage at selected depths and penetration...

Automated epidermis segmentation in histopathological images of human skin stained with hematoxylin and eosin

Science.gov (United States)

Kłeczek, Paweł; Dyduch, Grzegorz; Jaworek-Korjakowska, Joanna; Tadeusiewicz, Ryszard

2017-03-01

Background: Epidermis area is an important observation area for the diagnosis of inflammatory skin diseases and skin cancers. Therefore, in order to develop a computer-aided diagnosis system, segmentation of the epidermis area is usually an essential, initial step. This study presents an automated and robust method for epidermis segmentation in whole slide histopathological images of human skin, stained with hematoxylin and eosin. Methods: The proposed method performs epidermis segmentation based on the information about shape and distribution of transparent regions in a slide image and information about distribution and concentration of hematoxylin and eosin stains. It utilizes domain-specific knowledge of morphometric and biochemical properties of skin tissue elements to segment the relevant histopathological structures in human skin. Results: Experimental results on 88 skin histopathological images from three different sources show that the proposed method segments the epidermis with a mean sensitivity of 87 %, a mean specificity of 95% and a mean precision of 57%. It is robust to inter- and intra-image variations in both staining and illumination, and makes no assumptions about the type of skin disorder. The proposed method provides a superior performance compared to the existing techniques.

Quantification of Tissue Trauma following Insulin Pen Needle Insertions in Skin

DEFF Research Database (Denmark)

Jensen, Casper Bo; Larsen, Rasmus; Vestergaard, Jacob Schack

Objective: Within the field of pen needle development, most research on needle design revolves around mechanical tensile testing and patient statements. Only little has been published on the actual biological skin response to needle insertions. The objective of this study was to develop a computa......Objective: Within the field of pen needle development, most research on needle design revolves around mechanical tensile testing and patient statements. Only little has been published on the actual biological skin response to needle insertions. The objective of this study was to develop...... a computational method to quantify tissue trauma based on skin bleeding and immune response. Method: Two common sized pen needles of 28G (0.36mm) and 32G (0.23mm) were inserted into skin of sedated LYD pigs prior to termination. Four pigs were included and a total of 32 randomized needle insertions were conducted...... diameter. Conclusion: A computational and quantitative method has been developed to assess tissue trauma following insulin pen needle insertions. Application of the method is tested by conduction of a needle diameter study. The obtained quantitative measures of tissue trauma correlate positively to needle...

ORIGINAL ARTICLES Staphylococcus aureus skin and soft-tissue ...

African Journals Online (AJOL)

(MRSA) has become a key pathogen in skin and soft-tissue infections. (SSTIs). The emergence of ..... SSTI isolates; (iii) improved hospital infection control guidelines and practices to prevent .... So exposed in the field. And he'll never run off ...

Collagen cross-linking in sun-exposed and unexposed sites of aged human skin

Science.gov (United States)

Yamauchi, M.; Prisayanh, P.; Haque, Z.; Woodley, D. T.

1991-01-01

A recently described nonreducible, acid-heat stable compound, histidinohydroxylysinonorleucine (HHL), is a collagen cross-link isolated from mature skin tissue. Its abundance is related to chronologic aging of skin. The present communication describes the quantity of HHL from aged human skin of the same individuals in sun-exposed (wrist) and unexposed (buttock) sites. Punch biopsies were obtained from these sites from nine people of age 60 or older. HHL contents (moles/mole of collagen) at these sites were for wrist 0.13 +/- 0.07 and for buttock 0.69 +/- 0.17 (mean +/- SD, p less than 0.001). In addition, it was found that acute irradiation of the cross-linked peptides with UVA (up to 250 J/cm2) and UVB (up to 1 J/cm2) had no effect on HHL structure. The same treatment significantly degraded another nonreducible, stable collagen cross-link, pyridinoline. The results suggest that chronic sunlight exposure may be associated with an impediment to normal maturation of human dermal collagen resulting in tenuous amount of HHL. Thus, the process of photoaging in dermal collagen is different from that of chronologic aging in human skin.

Influence of hydration and experimental length scale on themechanical response of human skin in vivo, using optical coherence tomography

NARCIS (Netherlands)

Hendriks, F.M.; Brokken, D.; Oomens, C.W.J.; Baaijens, F.P.T.

2004-01-01

Human skin is a complex tissue consisting of different layers. To gain better insight into the mechanical behaviour of different skin layers, the mechanical response was studied with experiments of various length scales. Also, the influence of (superficial) hydration on the mechanical response is

From Cell to Tissue Properties-Modeling Skin Electroporation With Pore and Local Transport Region Formation.

Science.gov (United States)

Dermol-Cerne, Janja; Miklavcic, Damijan

2018-02-01

Current models of tissue electroporation either describe tissue with its bulk properties or include cell level properties, but model only a few cells of simple shapes in low-volume fractions or are in two dimensions. We constructed a three-dimensional model of realistically shaped cells in realistic volume fractions. By using a 'unit cell' model, the equivalent dielectric properties of whole tissue could be calculated. We calculated the dielectric properties of electroporated skin. We modeled electroporation of single cells by pore formation on keratinocytes and on the papillary dermis which gave dielectric properties of the electroporated epidermis and papillary dermis. During skin electroporation, local transport regions are formed in the stratum corneum. We modeled local transport regions and increase in their radii or density which affected the dielectric properties of the stratum corneum. The final model of skin electroporation accurately describes measured electric current and voltage drop on the skin during electroporation with long low-voltage pulses. The model also accurately describes voltage drop on the skin during electroporation with short high-voltage pulses. However, our results indicate that during application of short high-voltage pulses additional processes may occur which increase the electric current. Our model connects the processes occurring at the level of cell membranes (pore formation), at the level of a skin layer (formation of local transport region in the stratum corneum) with the tissue (skin layers) and even level of organs (skin). Using a similar approach, electroporation of any tissue can be modeled, if the morphology of the tissue is known.

Black and white human skin differences

DEFF Research Database (Denmark)

Andersen, Klaus Ejner; Maibach, H I

1979-01-01

This review of black and white human skin differences emphasizes the alleged importance of factors other than the obvious, i.e., skin color. Physicochemical differences and differences in susceptibility to irritants and allergens suggest a more resistant black than white skin. Differences appear...

Xenobiotic-metabolizing enzymes in the skin of rat, mouse, pig, guinea pig, man, and in human skin models.

Science.gov (United States)

Oesch, F; Fabian, E; Guth, K; Landsiedel, R

2014-12-01

The exposure of the skin to medical drugs, skin care products, cosmetics, and other chemicals renders information on xenobiotic-metabolizing enzymes (XME) in the skin highly interesting. Since the use of freshly excised human skin for experimental investigations meets with ethical and practical limitations, information on XME in models comes in the focus including non-human mammalian species and in vitro skin models. This review attempts to summarize the information available in the open scientific literature on XME in the skin of human, rat, mouse, guinea pig, and pig as well as human primary skin cells, human cell lines, and reconstructed human skin models. The most salient outcome is that much more research on cutaneous XME is needed for solid metabolism-dependent efficacy and safety predictions, and the cutaneous metabolism comparisons have to be viewed with caution. Keeping this fully in mind at least with respect to some cutaneous XME, some models may tentatively be considered to approximate reasonable closeness to human skin. For dermal absorption and for skin irritation among many contributing XME, esterase activity is of special importance, which in pig skin, some human cell lines, and reconstructed skin models appears reasonably close to human skin. With respect to genotoxicity and sensitization, activating XME are not yet judgeable, but reactive metabolite-reducing XME in primary human keratinocytes and several reconstructed human skin models appear reasonably close to human skin. For a more detailed delineation and discussion of the severe limitations see the "Overview and Conclusions" section in the end of this review.

TCDD induces dermal accumulation of keratinocyte-derived matrix metalloproteinase-10 in an organotypic model of human skin

Energy Technology Data Exchange (ETDEWEB)

De Abrew, K. Nadira [Molecular and Environmental Toxicology Center, University of Wisconsin—Madison, Madison, WI 53706 (United States); Thomas-Virnig, Christina L.; Rasmussen, Cathy A. [Department of Pathology, University of Wisconsin—Madison, Madison, WI 53706 (United States); Bolterstein, Elyse A. [Molecular and Environmental Toxicology Center, University of Wisconsin—Madison, Madison, WI 53706 (United States); Schlosser, Sandy J. [Department of Pathology, University of Wisconsin—Madison, Madison, WI 53706 (United States); Allen-Hoffmann, B. Lynn, E-mail: blallenh@wisc.edu [Molecular and Environmental Toxicology Center, University of Wisconsin—Madison, Madison, WI 53706 (United States); Department of Pathology, University of Wisconsin—Madison, Madison, WI 53706 (United States)

2014-05-01

The epidermis of skin is the first line of defense against the environment. A three dimensional model of human skin was used to investigate tissue-specific phenotypes induced by the environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Continuous treatment of organotypic cultures of human keratinocytes with TCDD resulted in intracellular spaces between keratinocytes of the basal and immediately suprabasal layers as well as thinning of the basement membrane, in addition to the previously reported hyperkeratinization. These tissue remodeling events were preceded temporally by changes in expression of the extracellular matrix degrading enzyme, matrix metalloproteinase-10 (MMP-10). In organotypic cultures MMP-10 mRNA and protein were highly induced following TCDD treatment. Q-PCR and immunoblot results from TCDD-treated monolayer cultures, as well as indirect immunofluorescence and immunoblot analysis of TCDD-treated organotypic cultures, showed that MMP-10 was specifically contributed by the epidermal keratinocytes but not the dermal fibroblasts. Keratinocyte-derived MMP-10 protein accumulated over time in the dermal compartment of organotypic cultures. TCDD-induced epidermal phenotypes in organotypic cultures were attenuated by the keratinocyte-specific expression of tissue inhibitor of metalloproteinase-1, a known inhibitor of MMP-10. These studies suggest that MMP-10 and possibly other MMP-10-activated MMPs are responsible for the phenotypes exhibited in the basement membrane, the basal keratinocyte layer, and the cornified layer of TCDD-treated organotypic cultures. Our studies reveal a novel mechanism by which the epithelial–stromal microenvironment is altered in a tissue-specific manner thereby inducing structural and functional pathology in the interfollicular epidermis of human skin. - Highlights: • TCDD causes hyperkeratosis and basement membrane changes in a model of human skin. • TCDD induces MMP-10 expression in organotypic cultures

Development of human skin equivalents to unravel the impaired skin barrier in atopic dermatitis skin

NARCIS (Netherlands)

Eweje, M.O.

2016-01-01

The studies in this thesis describes the barrier defects in Atopic Dermatitis (AD) skin and various techniques to develop AD Human Skin Equivalents (HSEs) which can be used to better understand the role of several factors in the pathogenesis of AD skin. The results described show that Inflammation

Volumetric Visualization of Human Skin

Science.gov (United States)

Kawai, Toshiyuki; Kurioka, Yoshihiro

We propose a modeling and rendering technique of human skin, which can provide realistic color, gloss and translucency for various applications in computer graphics. Our method is based on volumetric representation of the structure inside of the skin. Our model consists of the stratum corneum and three layers of pigments. The stratum corneum has also layered structure in which the incident light is reflected, refracted and diffused. Each layer of pigment has carotene, melanin or hemoglobin. The density distributions of pigments which define the color of each layer can be supplied as one of the voxel values. Surface normals of upper-side voxels are fluctuated to produce bumps and lines on the skin. We apply ray tracing approach to this model to obtain the rendered image. Multiple scattering in the stratum corneum, reflective and absorptive spectrum of pigments are considered. We also consider Fresnel term to calculate the specular component for glossy surface of skin. Some examples of rendered images are shown, which can successfully visualize a human skin.

Effects of radiation on the skin blood volume pulse in humans

Energy Technology Data Exchange (ETDEWEB)

Zanelli, G D [Mount Vernon Hospital, Northwood (UK)

1977-01-01

Measurements have been made of the changes in skin blood volume pulse (BVP) in the irradiated skin of three patients (two female, one male) during and up to 250 days after radiotherapy for malignant disease. The instrumentation comprised a modified commercial finger photo-plethysmograph probe with associated electronics, and a survey of the literature revealed that the consensus of opinion seems to be that the recorded pulsations arise from small 'muscular' arteries and arterioles in the 40 to 300 ..mu..m size range. The results show that, as expected, normal, untreated skin shows sizeable variations in BVP. The BVP of irradiated skin became significantly greater than that of normal skin when a dose of 1000 to 1500 rad has been accumulated. The maximum amplitude of the BVP of the irradiated skin seemed to correlate well with the overall severity of the erythema, but increases in BVP preceded erythema flare-ups. In two patients, elevated BVP were recorded for irradiated areas even when most visual signs of erythema had disappeared. Mild cooling of irradiated and non-irradiated skin had differing effects in the BVP. The measurement of the BVP of irradiated skin is a simple, reliable and completely atraumatic method for investigating vascular damage to superficial tissues in humans.

Analytical model of diffuse reflectance spectrum of skin tissue

Energy Technology Data Exchange (ETDEWEB)

Lisenko, S A; Kugeiko, M M; Firago, V A [Belarusian State University, Minsk (Belarus); Sobchuk, A N [B.I. Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk (Belarus)

2014-01-31

We have derived simple analytical expressions that enable highly accurate calculation of diffusely reflected light signals of skin in the spectral range from 450 to 800 nm at a distance from the region of delivery of exciting radiation. The expressions, taking into account the dependence of the detected signals on the refractive index, transport scattering coefficient, absorption coefficient and anisotropy factor of the medium, have been obtained in the approximation of a two-layer medium model (epidermis and dermis) for the same parameters of light scattering but different absorption coefficients of layers. Numerical experiments on the retrieval of the skin biophysical parameters from the diffuse reflectance spectra simulated by the Monte Carlo method show that commercially available fibre-optic spectrophotometers with a fixed distance between the radiation source and detector can reliably determine the concentration of bilirubin, oxy- and deoxyhaemoglobin in the dermis tissues and the tissue structure parameter characterising the size of its effective scatterers. We present the examples of quantitative analysis of the experimental data, confirming the correctness of estimates of biophysical parameters of skin using the obtained analytical expressions. (biophotonics)

An Adhesive Patch-Based Skin Biopsy Device for Molecular Diagnostics and Skin Microbiome Studies.

Science.gov (United States)

Yao, Zuxu; Moy, Ronald; Allen, Talisha; Jansen, Burkhard

2017-10-01

A number of diagnoses in clinical dermatology are currently histopathologically confirmed and this image recognition-based confirmation generally requires surgical biopsies. The increasing ability of molecular pathology to corroborate or correct a clinical diagnosis based on objective gene expression, mutation analysis, or molecular microbiome data is on the horizon and would be further supported by a tool or procedure to collect samples non-invasively. This study characterizes such a tool in form of a 'bladeless' adhesive patch-based skin biopsy device. The performance of this device was evaluated through a variety of complementary technologies including assessment of sample biomass, electron microscopy demonstrating the harvesting of layers of epidermal tissue, and isolation of RNA and DNA from epidermal skin samples. Samples were obtained by application of adhesive patches to the anatomical area of interest. Biomass assessment demonstrated collection of approximately 0.3mg of skin tissue per adhesive patch and electron microscopy confirmed the nature of the harvested epidermal skin tissue. The obtained tissue samples are stored in a stable fashion on adhesive patches over a wide range of temperatures (-80oC to +60oC) and for extended periods of time (7 days or more). Total human RNA, human genomic DNA and microbiome DNA yields were 23.35 + 15.75ng, 27.72 + 20.71ng and 576.2 + 376.8pg, respectively, in skin samples obtained from combining 4 full patches collected non-invasively from the forehead of healthy volunteers. The adhesive patch skin sampling procedure is well tolerated and provides robust means to obtain skin tissue, RNA, DNA, and microbiome samples without involving surgical biopsies. The non-invasively obtained skin samples can be shipped cost effectively at ambient temperature by mail or standard courier service, and are suitable for a variety of molecular analyses of the skin microbiome as well as of keratinocytes, T cells, dendritic cells

INFLUENCE OF LASER BEAM PROFILE ON LIGHT SCATTERING BY HUMAN SKIN DURING PHOTOMETRY BY ELLIPSOIDAL REFLECTORS

Directory of Open Access Journals (Sweden)

M. A. Bezuglyi

2018-01-01

Full Text Available The correct accounting of laser emitter parameters for improvement of diagnostic authenticity of methods of optical biomedical diagnostic is important problem for applied biophotonic tasks. The purpose of the current research is estimation of influence of energy distribution profile in transversal section of laser beam on light scattering by human skin layers at photometry by ellipsoidal reflectors.Biomedical photometer with ellipsoidal reflectors for investigation of biological tissue specimens in transmitted and reflected light uses laser probing radiation with infinitely thin, Gauss-type and uniform cross-section profile. Distribution of beams with denoted profiles, which consist of 20 million photons with wavelength 632.8 nm, was modeled by using of Monte-Carlo simulation in human skin layers (corneous layer, epidermis, derma and adipose tissue of various anatomic thickness and with ellipsoidal reflectors with focal parameter equal to 16.875 mm and eccentricity of 0.66.The modeling results represent that illuminance distribution in zones of photometric imaging is significantly influenced by the laser beam cross-section profile for various thickness of corneous layer and epidermis in transmitted and reflected light, and also derma in reflected light. Illuminance distribution for adipose tissue in reflected and transmitted light, and also derma in transmitted light, practically do not depend of laser beam profile for anatomic thicknesses, which are appropriate for human skin on various sections of body.There are represented results of modified Monte-Carlo simulation method for biomedical photometer with ellipsoidal reflectors during biometry of human skin layers. For highly scattered corneous layer and epidermis the illumination of middle and external rings of photometric images changes depending from the laser beam profile for more than 50 % in transmitted and 30 % in reflected light. For weakly scattering skin layers (derma and adipose layer

Raman spectroscopy of human skin: looking for a quantitative algorithm to reliably estimate human age

Science.gov (United States)

Pezzotti, Giuseppe; Boffelli, Marco; Miyamori, Daisuke; Uemura, Takeshi; Marunaka, Yoshinori; Zhu, Wenliang; Ikegaya, Hiroshi

2015-06-01

The possibility of examining soft tissues by Raman spectroscopy is challenged in an attempt to probe human age for the changes in biochemical composition of skin that accompany aging. We present a proof-of-concept report for explicating the biophysical links between vibrational characteristics and the specific compositional and chemical changes associated with aging. The actual existence of such links is then phenomenologically proved. In an attempt to foster the basics for a quantitative use of Raman spectroscopy in assessing aging from human skin samples, a precise spectral deconvolution is performed as a function of donors' ages on five cadaveric samples, which emphasizes the physical significance and the morphological modifications of the Raman bands. The outputs suggest the presence of spectral markers for age identification from skin samples. Some of them appeared as authentic "biological clocks" for the apparent exactness with which they are related to age. Our spectroscopic approach yields clear compositional information of protein folding and crystallization of lipid structures, which can lead to a precise identification of age from infants to adults. Once statistically validated, these parameters might be used to link vibrational aspects at the molecular scale for practical forensic purposes.

[Microbiological diagnosis of infections of the skin and soft tissues].

Science.gov (United States)

Burillo, Almudena; Moreno, Antonio; Salas, Carlos

2007-11-01

Skin and soft tissue infections are often seen in clinical practice, yet their microbiological diagnosis is among the most complex of laboratory tasks. The diagnosis of a skin and a soft tissue infection is generally based on clinical criteria and not microbiological results. A microbiological diagnosis is reserved for cases in which the etiology of infection is required, e.g., when the infection is particularly severe, when less common microorganisms are suspected as the causative agent (e.g. in immunocompromised patients), when response to antimicrobial treatment is poor, or when a longstanding wound does not heal within a reasonable period of time. We report the indications, sampling and processing techniques, and interpretation criteria for various culture types, including quantitative cultures from biopsy or tissue specimens and semiquantitative and qualitative cultures performed on all types of samples. For non-invasive samples taken from open wounds, application of the Q index to Gram stains is a cost-effective way to standardize sample quality assessment and interpretation of the pathogenic involvement of the different microorganisms isolated from cultures. All these issues are covered in the SEIMC microbiological procedure number 22: Diagnóstico microbiológico de las infecciones de piel y tejidos blandos (Microbiological diagnosis of infections of the skin and soft tissues) (2nd ed., 2006, www.seimc.org/protocolos/microbiologia).

Comparison of the effect of fatty alcohols on the permeation of melatonin between porcine and human skin.

Science.gov (United States)

Andega, S; Kanikkannan, N; Singh, M

2001-11-09

Melatonin (MT) is a hormone secreted by the pineal gland that plays an important role in the regulation of the circadian sleep-wake cycle. It would be advantageous to administer MT using a transdermal delivery system for the treatment of sleep disorders such as delayed sleep syndrome, jet lag in travelers, cosmonauts and shift workers. The porcine skin has been found to have similar morphological and functional characteristics as human skin. The elastic fibres in the dermis, enzyme pattern of the epidermis, epidermal tissue turnover time, keratinous proteins and thickness of epidermis of porcine skin are similar to human skin. However, the fat deposition and vascularisation of the cutaneous glands of porcine skin are different from human skin. In addition, porcine skin has been found to have a close permeability character to human skin. However, the comparative effect of chemical penetration enhancers on the permeation of drugs between porcine and human skin has not been reported. The purpose of this study was to compare the effect of fatty alcohols on the permeability of porcine and human skin using MT as a model compound. The effect of saturated fatty alcohols (octanol, nonanol, decanol, undecanol, lauryl alcohol, tridecanol, myristyl alcohol) and unsaturated fatty alcohols (oleyl alcohol, linoleyl alcohol, linolenyl alcohol) at 5% concentration was tested across dermatomed porcine and human skin. Our studies showed a parabolic relationship between the carbon chain length of saturated fatty alcohols and permeation enhancement of MT with both porcine and human skin. Maximum permeation of MT was observed when fatty alcohol carbon chain length was 10. In general, as the level of unsaturation increased from one to two double bonds, there was an increase in the permeation of MT both in porcine and human skin. However, a decrease in the permeation was observed with three double bonds. Regression analysis using the steady state flux data showed a significant positive

[Decellularized fish skin: characteristics that support tissue repair].

Science.gov (United States)

Magnússon, Skúli; Baldursson, Baldur Tumi; Kjartansson, Hilmar; Thorlacius, Guðný Ella; Axelsson, Ívar; Rolfsson, Óttar; Petersen, Pétur Henry; Sigurjónsson, Guðmundur Fertram

2015-12-01

Acellular fish skin of the Atlantic cod (Gadus morhua) is being used to treat chronic wounds. The prevalence of diabetes and the comorbidity of chronic wounds is increasing globally. The aim of the study was to assess the biocompatibility and biological characteristics of acellular fish skin, important for tissue repair. The structure of the acellular fish skin was examined with microscopy. Biocompatibility of the graft was conducted by a specialized certified laboratory. Protein extracts from the material were analyzed using gel electrophoresis. Cytokine levels were measured with an enzyme linked immunosorbent assay (ELISA). Angiogenic properties were assessed with a chick chorioallantoic membrane (chick CAM) assay. The structure of acellular fish skin is porous and the material is biocompatible. Electrophoresis revealed proteins around the size 115-130 kDa, indicative of collagens. The material did not have significant effect on IL-10, IL-12p40, IL-6 or TNF-α secretion from monocytes or macrophages. Acellular fish skin has significant effect on angiogenesis in the chick CAM assay. The acellular fish skin is not toxic and is not likely to promote inflammatory responses. The graft contains collagen I, promotes angiogenesis and supports cellular ingrowth. Compared to similar products made from mammalian sources, acellular fish skin does not confer a disease risk and contains more bioactive compounds, due to less severe processing.

Gingival Tissue Color Related With Facial Skin and Acrylic Resin ...

African Journals Online (AJOL)

The objective of this study is to determine the predominant gingival tissue colour in this environment; to assess the association of gingival tissue colour with gender and facial skin colour. Four hundred and thirty subjects that attended the Dental Centre, University College Hospital, Ibadan, who consented to participate in the ...

Tissue engineering skin: a paradigm shift in wound care.

Science.gov (United States)

Mason, C

2005-12-01

Tissue-engineered skin for the treatment of burns and ulcers is a clinical success, but making it commercially viable is more problematic. This article examines the industry, its techniques and suggests the way forward.

Studies of the in vivo radiosensitivity of human skin fibroblasts

International Nuclear Information System (INIS)

Hill, Richard P.; Kaspler, Pavel; Griffin, Anthony M.; O'Sullivan, Brian; Catton, Charles; Alasti, Hamideh; Abbas, Ahmar; Heydarian, Moustafa; Ferguson, Peter; Wunder, Jay S.; Bell, Robert S.

2007-01-01

Background and purpose: To examine the radiosensitivity of skin cells obtained directly from the irradiated skin of patients undergoing fractionated radiation treatment prior to surgery for treatment of soft tissue sarcoma (STS) and to determine if there was a relationship with the development of wound healing complications associated with the surgery post-radiotherapy. Methods: Micronucleus (MN) formation was measured in cells (primarily dermal fibroblasts) obtained from human skin at their first division after being removed from STS patients during post-radiotherapy surgery (2-9 weeks after the end of the radiotherapy). At the time of radiotherapy (planned tumor dose - 50 Gy in 25 daily fractions) measurements were made of surface skin dose at predetermined marked sites. Skin from these sites was obtained at surgery and cell suspensions were prepared directly for the cytokinesis-blocked MN assay. Cultured strains of the fibroblasts were also established from skin nominally outside the edge of the radiation beam and DNA damage (MN formation) was examined following irradiation in vitro for comparison with the results from the in situ irradiations. Results: Extensive DNA damage (MN) was detectable in fibroblasts from human skin at extended periods after irradiation (2-9 weeks after the end of the 5-week fractionated radiotherapy). Analysis of skin receiving a range of doses demonstrated that the level of damage observed was dose dependent. There was no clear correlation between the level of damage observed after irradiation in situ and irradiation of cell strains in culture. Similarly, there was no correlation between the extent of MN formation following in situ irradiation and the propensity for the patient to develop wound healing complications post-surgery. Conclusions: Despite the presence of DNA damage in dermal fibroblasts weeks after the end of the radiation treatment, there was no relationship between this damage and wound healing complications following

Neurogenic inflammation in human and rodent skin

DEFF Research Database (Denmark)

Schmelz, M; Petersen, Lars Jelstrup

2001-01-01

The combination of vasodilation and protein extravasation following activation of nociceptors has been termed "neurogenic inflammation." In contrast to rodents, no neurogenic protein extravasation can be elicited in healthy human skin. Dermal microdialysis has considerably increased our knowledge...... about neurogenic inflammation in human skin, including the involvement of mast cells.......The combination of vasodilation and protein extravasation following activation of nociceptors has been termed "neurogenic inflammation." In contrast to rodents, no neurogenic protein extravasation can be elicited in healthy human skin. Dermal microdialysis has considerably increased our knowledge...

Establishment and function of tissue-resident innate lymphoid cells in the skin

Directory of Open Access Journals (Sweden)

Jie Yang

2017-03-01

Full Text Available ABSTRACT Innate lymphoid cells (ILCs are a newly classified family of immune cells of the lymphoid lineage. While they could be found in both lymphoid organs and non-lymphoid tissues, ILCs are preferentially enriched in barrier tissues such as the skin, intestine, and lung where they could play important roles in maintenance of tissue integrity and function and protection against assaults of foreign agents. On the other hand, dysregulated activation of ILCs could contribute to tissue inflammatory diseases. In spite of recent progress towards understanding roles of ILCs in the health and disease, mechanisms regulating specific establishment, activation, and function of ILCs in barrier tissues are still poorly understood. We herein review the up-to-date understanding of tissue-specific relevance of ILCs. Particularly we will focus on resident ILCs of the skin, the outmost barrier tissue critical in protection against various foreign hazardous agents and maintenance of thermal and water balance. In addition, we will discuss remaining outstanding questions yet to be addressed.

Establishment and function of tissue-resident innate lymphoid cells in the skin.

Science.gov (United States)

Yang, Jie; Zhao, Luming; Xu, Ming; Xiong, Na

2017-07-01

Innate lymphoid cells (ILCs) are a newly classified family of immune cells of the lymphoid lineage. While they could be found in both lymphoid organs and non-lymphoid tissues, ILCs are preferentially enriched in barrier tissues such as the skin, intestine, and lung where they could play important roles in maintenance of tissue integrity and function and protection against assaults of foreign agents. On the other hand, dysregulated activation of ILCs could contribute to tissue inflammatory diseases. In spite of recent progress towards understanding roles of ILCs in the health and disease, mechanisms regulating specific establishment, activation, and function of ILCs in barrier tissues are still poorly understood. We herein review the up-to-date understanding of tissue-specific relevance of ILCs. Particularly we will focus on resident ILCs of the skin, the outmost barrier tissue critical in protection against various foreign hazardous agents and maintenance of thermal and water balance. In addition, we will discuss remaining outstanding questions yet to be addressed.

Skin grafting and tissue replacement for treating foot ulcers in people with diabetes

NARCIS (Netherlands)

Santema, Trientje B.; Poyck, Paul P. C.; Ubbink, Dirk T.

2016-01-01

Foot ulceration is a major problem in people with diabetes and is the leading cause of hospitalisation and limb amputations. Skin grafts and tissue replacements can be used to reconstruct skin defects for people with diabetic foot ulcers in addition to providing them with standard care. Skin

Unmixing chromophores in human skin with a 3D multispectral optoacoustic mesoscopy system

Science.gov (United States)

Schwarz, Mathias; Aguirre, Juan; Soliman, Dominik; Buehler, Andreas; Ntziachristos, Vasilis

2016-03-01

The absorption of visible light by human skin is governed by a number of natural chromophores: Eumelanin, pheomelanin, oxyhemoglobin, and deoxyhemoglobin are the major absorbers in the visible range in cutaneous tissue. Label-free quantification of these tissue chromophores is an important step of optoacoustic (photoacoustic) imaging towards clinical application, since it provides relevant information in diseases. In tumor cells, for instance, there are metabolic changes (Warburg effect) compared to healthy cells, leading to changes in oxygenation in the environment of tumors. In malignant melanoma changes in the absorption spectrum have been observed compared to the spectrum of nonmalignant nevi. So far, optoacoustic imaging has been applied to human skin mostly in single-wavelength mode, providing anatomical information but no functional information. In this work, we excited the tissue by a tunable laser source in the spectral range from 413-680 nm with a repetition rate of 50 Hz. The laser was operated in wavelengthsweep mode emitting consecutive pulses at various wavelengths that allowed for automatic co-registration of the multispectral datasets. The multispectral raster-scan optoacoustic mesoscopy (MSOM) system provides a lateral resolution of melanin, oxyhemoglobin, and deoxyhemoglobin, three-dimensional absorption maps of all three absorbers were calculated from the multispectral dataset.

The skin immune system (SIS): distribution and immunophenotype of lymphocyte subpopulations in normal human skin

NARCIS (Netherlands)

Bos, J. D.; Zonneveld, I.; Das, P. K.; Krieg, S. R.; van der Loos, C. M.; Kapsenberg, M. L.

1987-01-01

The complexity of immune response-associated cells present in normal human skin was recently redefined as the skin immune system (SIS). In the present study, the exact immunophenotypes of lymphocyte subpopulations with their localizations in normal human skin were determined quantitatively. B cells

Adaptation of the dermal collagen structure of human skin and scar tissue in response to stretch: An experimental study

NARCIS (Netherlands)

Verhaegen, Pauline D.; Schouten, Hennie J.; Tigchelaar-Gutter, Wikky; van Marle, Jan; van Noorden, Cornelis J.; Middelkoop, Esther; van Zuijlen, Paul P.

2012-01-01

Surgeons are often faced with large defects that are difficult to close. Stretching adjacent skin can facilitate wound closure. In clinical practice, intraoperative stretching is performed in a cyclical or continuous fashion. However, exact mechanisms of tissue adaptation to stretch remain unclear.

WE-AB-303-04: A Tissue Model of Cherenkov Emission From the Skin Surface During Megavoltage X-Ray Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Wiles, A. N.; Loyalka, S. K. [University of Missouri, Columbia, MO (United States); Izaguirre, E. W. [University of Missouri, Columbia, MO (United States); Baylor Scott & White Health, Temple, TX (United States)

2015-06-15

Purpose: To develop a tissue model of Cherenkov radiation emitted from the skin surface during external beam radiotherapy. Imaging Cherenkov radiation emitted from human skin allows visualization of the beam position and potentially surface dose estimates, and our goal is to characterize the optical properties of these emissions. Methods: We developed a Monte Carlo model of Cherenkov radiation generated in a semi-infinite tissue slab by megavoltage x-ray beams with optical transmission properties determined by a two-layered skin model. We separate the skin into a dermal and an epidermal layer in our model, where distinct molecular absorbers modify the Cherenkov intensity spectrum in each layer while we approximate the scattering properties with Mie and Rayleigh scattering from the highly structured molecular organization found in human skin. Results: We report on the estimated distributions of the Cherenkov wavelength spectrum, emission angles, and surface distribution for the modeled irradiated skin surface. The expected intensity distribution of Cherenkov radiation emitted from skin shows a distinct intensity peak around 475 nm, the blue region of the visible spectrum, between a pair of optical absorption bands in hemoglobin and a broad plateau beginning near 600 nm and extending to at least 700 nm where melanin and hemoglobin absorption are both low. We also find that the Cherenkov intensity decreases with increasing angle from the surface normal, the majority being emitted within 20 degrees of the surface normal. Conclusion: Our estimate of the spectral distribution of Cherenkov radiation emitted from skin indicates an advantage to using imaging devices with long wavelength spectral responsivity. We also expect the most efficient imaging to be near the surface normal where the intensity is greatest; although for contoured surfaces, the relative intensity across the surface may appear to vary due to decreasing Cherenkov intensity with increased angle from the

Current Concepts in Tissue Engineering: Skin and Wound.

Science.gov (United States)

Tenenhaus, Mayer; Rennekampff, Hans-Oliver

2016-09-01

Pure regenerative healing with little to no donor morbidity remains an elusive goal for both surgeon and patient. The ability to engineer and promote the development of like tissue holds so much promise, and efforts in this direction are slowly but steadily advancing. Products selected and reviewed reflect historical precedence and importance and focus on current clinically available products in use. Emerging technologies we anticipate will further expand our therapeutic options are introduced. The topic of tissue engineering is incredibly broad in scope, and as such the authors have focused their review on that of constructs specifically designed for skin and wound healing. A review of pertinent and current clinically related literature is included. Products such as biosynthetics, biologics, cellular promoting factors, and commercially available matrices can be routinely found in most modern health care centers. Although to date no complete regenerative or direct identical soft-tissue replacement exists, currently available commercial components have proven beneficial in augmenting and improving some types of wound healing scenarios. Cost, directed specificity, biocompatibility, and bioburden tolerance are just some of the impending challenges to adoption. Quality of life and in fact the ability to sustain life is dependent on our most complex and remarkable organ, skin. Although pure regenerative healing and engineered soft-tissue constructs elude us, surgeons and health care providers are slowly gaining comfort and experience with concepts and strategies to improve the healing of wounds.

Advanced haptic sensor for measuring human skin conditions

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Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

2010-01-01

This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

Skin grafting and tissue replacement for treating foot ulcers in people with diabetes.

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Santema, Trientje B; Poyck, Paul P C; Ubbink, Dirk T

2016-02-11

Foot ulceration is a major problem in people with diabetes and is the leading cause of hospitalisation and limb amputations. Skin grafts and tissue replacements can be used to reconstruct skin defects for people with diabetic foot ulcers in addition to providing them with standard care. Skin substitutes can consist of bioengineered or artificial skin, autografts (taken from the patient), allografts (taken from another person) or xenografts (taken from animals). To determine the benefits and harms of skin grafting and tissue replacement for treating foot ulcers in people with diabetes. In April 2015 we searched: The Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. We also searched clinical trial registries to identify ongoing studies. We did not apply restrictions to language, date of publication or study setting. Randomised clinical trials (RCTs) of skin grafts or tissue replacements for treating foot ulcers in people with diabetes. Two review authors independently extracted data and assessed the quality of the included studies. We included seventeen studies with a total of 1655 randomised participants in this review. Risk of bias was variable among studies. Blinding of participants, personnel and outcome assessment was not possible in most trials because of obvious differences between the treatments. The lack of a blinded outcome assessor may have caused detection bias when ulcer healing was assessed. However, possible detection bias is hard to prevent due to the nature of the skin replacement products we assessed, and the fact that they are easily recognisable. Strikingly, nearly all studies (15/17) reported industry involvement; at least one of the authors was connected to a commercial organisation or the study was funded by a commercial organisation. In addition, the funnel plot for

Transplantation of Human Skin-Derived Mesenchymal Stromal Cells Improves Locomotor Recovery After Spinal Cord Injury in Rats.

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Melo, Fernanda Rosene; Bressan, Raul Bardini; Forner, Stefânia; Martini, Alessandra Cadete; Rode, Michele; Delben, Priscilla Barros; Rae, Giles Alexander; Figueiredo, Claudia Pinto; Trentin, Andrea Gonçalves

2017-07-01

Spinal cord injury (SCI) is a devastating neurologic disorder with significant impacts on quality of life, life expectancy, and economic burden. Although there are no fully restorative treatments yet available, several animal and small-scale clinical studies have highlighted the therapeutic potential of cellular interventions for SCI. Mesenchymal stem cells (MSCs)-which are conventionally isolated from the bone marrow-recently emerged as promising candidates for treating SCI and have been shown to provide trophic support, ameliorate inflammatory responses, and reduce cell death following the mechanical trauma. Here we evaluated the human skin as an alternative source of adult MSCs suitable for autologous cell transplantation strategies for SCI. We showed that human skin-derived MSCs (hSD-MSCs) express a range of neural markers under standard culture conditions and are able to survive and respond to neurogenic stimulation in vitro. In addition, using histological analysis and behavioral assessment, we demonstrated as a proof-of-principle that hSD-MSC transplantation reduces the severity of tissue loss and facilitates locomotor recovery in a rat model of SCI. Altogether, the study provides further characterization of skin-derived MSC cultures and indicates that the human skin may represent an attractive source for cell-based therapies for SCI and other neurological disorders. Further investigation is needed to elucidate the mechanisms by which hSD-MSCs elicit tissue repair and/or locomotor recovery.

Nonexpansive immediate breast reconstruction using human acellular tissue matrix graft (AlloDerm).

Science.gov (United States)

Salzberg, C Andrew

2006-07-01

Immediate breast reconstruction has become a standard of care following mastectomy for cancer, largely due to improved esthetic and psychologic outcomes achieved with this technique. However, the current historical standards--transverse rectus abdominis myocutaneous flap reconstruction and expander--implant surgery-still have limitations as regards patient morbidity, short-term body-image improvements, and even cost. To address these shortcomings, we employ a novel concept of human tissue replacement to enhance breast shape and provide total coverage, enabling immediate mound reconstruction without the need for breast expansion prior to permanent implant placement. AlloDerm (human acellular tissue matrix) is a human-derived graft tissue with extensive experience in various settings of skin and soft tissue replacement surgery. This report describes the success using acellular tissue matrix to provide total coverage over the prosthesis in immediate reconstruction, with limited muscle dissection. In this population, 49 patients (76 breasts) successfully underwent the acellular tissue matrix-based immediate reconstruction, resulting in durable breast reconstruction with good symmetry. These findings may predict that acellular tissue matrix-supplemented immediate breast reconstruction will become a new technique for the immediate reconstruction of the postmastectomy breast.

Fabrication of a nanofibrous scaffold with improved bioactivity for culture of human dermal fibroblasts for skin regeneration

Energy Technology Data Exchange (ETDEWEB)

Chandrasekaran, Arun Richard; Venugopal, J; Sundarrajan, S; Ramakrishna, S, E-mail: nnijrv@nus.edu.s [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore (Singapore)

2011-02-15

Engineering dermal substitutes with electrospun nanofibres have lately been of prime importance for skin tissue regeneration. Simple electrospinning technology served to produce nanofibrous scaffolds morphologically and structurally similar to the extracellular matrix of native tissues. The nanofibrous scaffolds of poly(l-lactic acid)-co-poly({epsilon}-caprolactone) (PLACL) and PLACL/gelatin complexes were fabricated by the electrospinning process. These nanofibres were characterized for fibre morphology, membrane porosity, wettability and chemical properties by FTIR analysis to culture human foreskin fibroblasts for skin tissue engineering. The nanofibre diameter was obtained between 282 and 761 nm for PLACL and PLACL/gelatin scaffolds; expressions of amino and carboxyl groups and porosity up to 87% were obtained for these fibres, while they also exhibited improved hydrophilic properties after plasma treatment. The results showed that fibroblasts proliferation, morphology, CMFDA dye expression and secretion of collagen were significantly increased in plasma-treated PLACL/gelatin scaffolds compared to PLACL nanofibrous scaffolds. The obtained results prove that the plasma-treated PLACL/gelatin nanofibrous scaffold is a potential biocomposite material for skin tissue regeneration.

Fabrication of a nanofibrous scaffold with improved bioactivity for culture of human dermal fibroblasts for skin regeneration

International Nuclear Information System (INIS)

Chandrasekaran, Arun Richard; Venugopal, J; Sundarrajan, S; Ramakrishna, S

2011-01-01

Engineering dermal substitutes with electrospun nanofibres have lately been of prime importance for skin tissue regeneration. Simple electrospinning technology served to produce nanofibrous scaffolds morphologically and structurally similar to the extracellular matrix of native tissues. The nanofibrous scaffolds of poly(l-lactic acid)-co-poly(ε-caprolactone) (PLACL) and PLACL/gelatin complexes were fabricated by the electrospinning process. These nanofibres were characterized for fibre morphology, membrane porosity, wettability and chemical properties by FTIR analysis to culture human foreskin fibroblasts for skin tissue engineering. The nanofibre diameter was obtained between 282 and 761 nm for PLACL and PLACL/gelatin scaffolds; expressions of amino and carboxyl groups and porosity up to 87% were obtained for these fibres, while they also exhibited improved hydrophilic properties after plasma treatment. The results showed that fibroblasts proliferation, morphology, CMFDA dye expression and secretion of collagen were significantly increased in plasma-treated PLACL/gelatin scaffolds compared to PLACL nanofibrous scaffolds. The obtained results prove that the plasma-treated PLACL/gelatin nanofibrous scaffold is a potential biocomposite material for skin tissue regeneration.

UWB pulse propagation into human tissues

International Nuclear Information System (INIS)

Cavagnaro, Marta; Pittella, Erika; Pisa, Stefano

2013-01-01

In this paper the propagation of a UWB pulse into a layered model of the human body is studied to characterize absorption and reflection of the UWB signal due to the different body tissues. Several time behaviours for the incident UWB pulse are considered and compared with reference to the feasibility of breath and heartbeat activity monitoring. Results show that if the UWB source is placed far from the human body, the reflection coming from the interface between air and skin can be used to detect the respiratory activity. On the contrary, if the UWB source is placed close to the human body, a small reflection due to the interface between the posterior lung wall and the bone, which is well distanced in time from the reflections due to the first layers of the body model, can be used to detect lung and heart changes associated with the cardio-respiratory activity. (paper)

Materials used to simulate physical properties of human skin.

Science.gov (United States)

Dąbrowska, A K; Rotaru, G-M; Derler, S; Spano, F; Camenzind, M; Annaheim, S; Stämpfli, R; Schmid, M; Rossi, R M

2016-02-01

For many applications in research, material development and testing, physical skin models are preferable to the use of human skin, because more reliable and reproducible results can be obtained. This article gives an overview of materials applied to model physical properties of human skin to encourage multidisciplinary approaches for more realistic testing and improved understanding of skin-material interactions. The literature databases Web of Science, PubMed and Google Scholar were searched using the terms 'skin model', 'skin phantom', 'skin equivalent', 'synthetic skin', 'skin substitute', 'artificial skin', 'skin replica', and 'skin model substrate.' Articles addressing material developments or measurements that include the replication of skin properties or behaviour were analysed. It was found that the most common materials used to simulate skin are liquid suspensions, gelatinous substances, elastomers, epoxy resins, metals and textiles. Nano- and micro-fillers can be incorporated in the skin models to tune their physical properties. While numerous physical skin models have been reported, most developments are research field-specific and based on trial-and-error methods. As the complexity of advanced measurement techniques increases, new interdisciplinary approaches are needed in future to achieve refined models which realistically simulate multiple properties of human skin. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Increased tissue leptin hormone level and mast cell count in skin tags: A possible role of adipoimmune in the growth of benign skin growths

Directory of Open Access Journals (Sweden)

El Safoury Omar

2010-01-01

Full Text Available Background: Skin tags (ST are common tumors. They mainly consist of loose fibrous tissue and occur on the neck and major flexures as small, soft, pedunculated protrusions. Decrease in endocrine, hormone level and other factors are thought to play a role in the evolution of ST. Leptin is an adipocyte-derived hormone that acts as a major regulatory hormone for food intake and energy homeostasis. Leptin deficiency or resistance can result in profound obesity and diabetes in humans. A role of mast cell in the pathogenesis of ST is well recognized. Aims: To investigate the role of leptin in the pathogenesis of ST and to clarify whether there is a correlation between mast cell count and leptin level in ST. Methods: Forty-five skin biopsies were taken from 15 patients with ST. From each patient, a biopsy of a large ST (length >4 mm, a small ST (length <2 mm and a normal skin biopsy (as a control were taken. The samples were processed for leptin level. Skin biopsies were stained with hematoxylin and eosin and toluidine blue-uranyl nitrate metachromatic method for mast cell count was used. Results: There was a significant increased level of leptin in the ST compared to the normal skin. It was highly significant in small ST than in big ST (P = 0.0001 and it was highly significant in small and big ST compared to controls, P = 0.0001 and P = 0.001, respectively. There was a significant increase in mast cell count in the ST, which did not correlate with the increased levels of leptin. Conclusion: This is the first report to demonstrate that tissue leptin may play a role in the pathogenesis of ST. The significant increase in the levels of leptin and mast cell count in ST may indicate a possible role of adipoimmune in the benign skin growths.

Evaluation of dermal-epidermal skin equivalents ('composite-skin') of human keratinocytes in a collagen-glycosaminoglycan matrix(Integra artificial skin).

Science.gov (United States)

Kremer, M; Lang, E; Berger, A C

2000-09-01

Integra artificial skin (Integra LifeSciences Corp., Plainsboro, NJ, USA) is a dermal template consisting of bovine collagen, chondroitin-6-sulphate and a silastic membrane manufactured as Integra. This product has gained widespread use in the clinical treatment of third degree burn wounds and full thickness skin defects of different aetiologies. The product was designed to significantly reduce the time needed to achieve final wound closure in the treatment of major burn wounds, to optimise the sparse autologous donor skin resources and to improve the durable mechanical quality of the skin substitute. The clinical procedure requires two stages. The first step creates a self neodermis, the second creates a self epidermis on the neodermis. However, it is desirable to cover major burn wounds early in a single step by a skin substitute consisting of a dermal equivalent seeded in vitro with autologous keratinocytes ('composite-skin') out of which a full thickness skin develops in vivo.The goal of this experimental study was to develop a method to integrate human keratinocytes in homogeneous distribution and depth into Integra Artificial Skin. The seeded cell-matrix composites were grafted onto athymic mice in order to evaluate their potential to reconstitute a human epidermis in vivo. We were able to demonstrate that the inoculated human keratinocytes reproducibly displayed a homogeneous pattern of distribution, adherence, proliferation and confluence. The cell-matrix composites grafted in this model exhibited good wound adherence, complete healing, minor wound contraction and had the potential to reconstitute an elastic, functional and durable human skin. Histologically we were able to show that the inoculated human keratinocytes in vivo colonised the matrix in a histomorphologically characteristic epidermal pattern (keratomorula, keratinocyte bubbling) and developed a persisting, stratified, keratinising epidermis which immunohistologically proved to be of human

Assessment of organ culture for the conservation of human skin allografts.

Science.gov (United States)

Hautier, A; Sabatier, F; Stellmann, P; Andrac, L; Nouaille De Gorce, Y; Dignat-George, F; Magalon, G

2008-03-01

Human skin allografts are used in the treatment of severe burns and their preservation is therefore critical for optimal clinical benefit. Current preservation methods, such as 4 degrees C storage or cryopreservation, cannot prevent the decrease of tissue viability. The aim of this study was to assess viability and function of skin allografts in a new skin organ culture model, allowing conservation parameters as close as possible to physiological conditions: 32 degrees C, air-liquid interface and physiological skin tension. Twelve skin samples, harvested from 6 living surgical donors, were conserved 35 days in two conditions: conservation at 4 degrees C and organ culture. Viability and function of skin samples were investigated at Day 0, 7, 14, 21, 28 and 35 using cell culture methods (trypan blue exclusion, Colony Forming Efficiency and Growth Rate), histopathological and histoenzymological studies (Ki67 immunostaining). In the two conditions, fibroblast and keratinocyte viability was progressively affected by storage, with a significant decrease observed after 35 days. No statistical difference could be observed between the two conditions. The two methods were also comparable regarding alterations of fibroblast and keratinocyte culture parameters, which were respectively significantly reduced at Day 7 and 21, compared to fresh skin. By contrast, histopathological and histoenzymological studies revealed a better preservation of skin architecture and proliferative potential at 4 degrees C, as compared to organ culture. These results indicate that skin organ culture does not provide significant advantages for skin allograft preservation. However, its potential use as an experimental model to study skin physiology and wound healing should be further evaluated.

Skin-Resident T Cells Drive Dermal Dendritic Cell Migration in Response to Tissue Self-Antigen.

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Ali, Niwa; Zirak, Bahar; Truong, Hong-An; Maurano, Megan M; Gratz, Iris K; Abbas, Abul K; Rosenblum, Michael D

2018-05-01

Migratory dendritic cell (DC) subsets deliver tissue Ags to draining lymph nodes (DLNs) to either initiate or inhibit T cell-mediated immune responses. The signals mediating DC migration in response to tissue self-antigen are largely unknown. Using a mouse model of inducible skin-specific self-antigen expression, we demonstrate that CD103 + dermal DCs (DDCs) rapidly migrate from skin to skin DLN (SDLNs) within the first 48 h after Ag expression. This window of time was characterized by the preferential activation of tissue-resident Ag-specific effector T cells (Teffs), with no concurrent activation of Ag-specific Teffs in SDLNs. Using genetic deletion and adoptive transfer approaches, we show that activation of skin-resident Teffs is required to drive CD103 + DDC migration in response to tissue self-antigen and this Batf3-dependent DC population is necessary to mount a fulminant autoimmune response in skin. Conversely, activation of Ag-specific Teffs in SDLNs played no role in DDC migration. Our studies reveal a crucial role for skin-resident T cell-derived signals, originating at the site of self-antigen expression, to drive DDC migration during the elicitation phase of an autoimmune response. Copyright © 2018 by The American Association of Immunologists, Inc.

Biophotonics in diagnosis and modeling of tissue pathologies

Science.gov (United States)

Serafetinides, A. A.; Makropoulou, M.; Drakaki, E.

2008-12-01

Biophotonics techniques are applied to several fields in medicine and biology. The laser based techniques, such as the laser induced fluorescence (LIF) spectroscopy and the optical coherence tomography (OCT), are of particular importance in dermatology, where the laser radiation could be directly applied to the tissue target (e.g. skin). In addition, OCT resolves architectural tissue properties that might be useful as tumour discrimination parameters for skin as well as for ocular non-invasive visualization. Skin and ocular tissues are complex multilayered and inhomogeneous organs with spatially varying optical properties. This fact complicates the quantitative analysis of the fluorescence and/or light scattering spectra, even from the same tissue sample. To overcome this problem, mathematical simulation is applied for the investigation of the human tissue optical properties, in the visible/infrared range of the spectrum, resulting in a better discrimination of several tissue pathologies. In this work, we present i) a general view on biophotonics applications in diagnosis of human diseases, ii) some specific results on laser spectroscopy techniques, as LIF measurements, applied in arterial and skin pathologies and iii) some experimental and theoretical results on ocular OCT measurements. Regarding the LIF spectroscopy, we examined the autofluorescence properties of several human skin samples, excised from humans undergoing biopsy examination. A nitrogen laser was used as an excitation source, emitting at 337 nm (ultraviolet excitation). Histopathology examination of the samples was also performed, after the laser spectroscopy measurements and the results from the spectroscopic and medical analysis were compared, to differentiate malignancies, e.g. basal cell carcinoma tissue (BCC), from normal skin tissue. Regarding the OCT technique, we correlated human data, obtained from patients undergoing OCT examination, with Monte Carlo simulated cornea and retina tissues

The effect of low dose ionizing radiation on homeostasis and functional integrity in an organotypic human skin model

Energy Technology Data Exchange (ETDEWEB)

Neubeck, Claere von [German Cancer Consortium DKTK partner site Dresden, OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstrasse 74, 01307 Dresden (Germany); German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg (Germany); Geniza, Matthew J. [Molecular and Cellular Biology Program, Oregon State University, Corvallis OR 97331 (United States); Kauer, Paula M.; Robinson, R. Joe; Chrisler, William B. [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland WA 99352 (United States); Sowa, Marianne B., E-mail: marianne.sowa@pnnl.gov [Health Impacts and Exposure Science, Pacific Northwest National Laboratory, Richland WA 99352 (United States)

2015-05-15

Highlights: • Low doses of high LET radiation influence skin homeostasis. • Effects on proliferation and differentiation profiles are LET dependent. • Skin barrier function is not compromised following low dose exposure. - Abstract: Outside the protection of Earth's atmosphere, astronauts are exposed to low doses of high linear energy transfer (LET) radiation. Future NASA plans for deep space missions or a permanent settlement on the moon are limited by the health risks associated with space radiation exposures. There is a paucity of direct epidemiological data for low dose exposures to space radiation-relevant high LET ions. Health risk models are used to estimate the risk for such exposures, though these models are based on high dose experiments. There is increasing evidence, however, that low and high dose exposures result in different signaling events at the molecular level, and may involve different response mechanisms. Further, despite their low abundance, high LET particles have been identified as the major contributor to health risk during manned space flight. The human skin is exposed in every external radiation scenario, making it an ideal epithelial tissue model in which to study radiation induced effects. Here, we exposed an in vitro three dimensional (3-D) human organotypic skin tissue model to low doses of high LET oxygen (O), silicon (Si) and iron (Fe) ions. We measured proliferation and differentiation profiles in the skin tissue and examined the integrity of the skin's barrier function. We discuss the role of secondary particles in changing the proportion of cells receiving a radiation dose, emphasizing the possible impact on radiation-induced health issues in astronauts.

Human soft tissue analysis using x-ray or gamma-ray techniques

International Nuclear Information System (INIS)

Theodorakou, C; Farquharson, M J

2008-01-01

This topical review is intended to describe the x-ray techniques used for human soft tissue analysis. X-ray techniques have been applied to human soft tissue characterization and interesting results have been presented over the last few decades. The motivation behind such studies is to provide improved patient outcome by using the data obtained to better understand a disease process and improve diagnosis. An overview of theoretical background as well as a complete set of references is presented. For each study, a brief summary of the methodology and results is given. The x-ray techniques include x-ray diffraction, x-ray fluorescence, Compton scattering, Compton to coherent scattering ratio and attenuation measurements. The soft tissues that have been classified using x-rays or gamma rays include brain, breast, colon, fat, kidney, liver, lung, muscle, prostate, skin, thyroid and uterus. (topical review)

Human skin penetration of silver nanoparticles through intact and damaged skin

International Nuclear Information System (INIS)

Larese, Francesca Filon; D'Agostin, Flavia; Crosera, Matteo; Adami, Gianpiero; Renzi, Nadia; Bovenzi, Massimo; Maina, Giovanni

2009-01-01

There is a growing interest on nanoparticle safety for topical use. The benefits of nanoparticles have been shown in several scientific fields, but little is known about their potential to penetrate the skin. This study aims at evaluating in vitro skin penetration of silver nanoparticles. Experiments were performed using the Franz diffusion cell method with intact and damaged human skin. Physiological solution was used as receiving phase and 70 μg/cm 2 of silver nanoparticles coated with polyvinylpirrolidone dispersed in synthetic sweat were applied as donor phase to the outer surface of the skin for 24 h. The receptor fluid measurements were performed by electro thermal atomic absorption spectroscopy (ETAAS). Human skin penetration was also determined by using transmission electron microscope (TEM) to verify the location of silver nanoparticles in exposed membranes. Median silver concentrations of 0.46 ng cm -2 (range -2 (range 0.43-11.6) were found in the receiving solutions of cells where the nanoparticles solution was applied on intact skin (eight cells) and on damaged skin (eight cells), respectively. Twenty-four hours silver flux permeation in damaged skin was 0.62 ± 0.2 ng cm -2 with a lag time <1 h. Our experimental data showed that silver nanoparticles absorption through intact and damaged skin was very low but detectable, and that in case of damaged skin it was possible an increasing permeation of silver applied as nanoparticles. Moreover, silver nanoparticles could be detected in the stratum corneum and the outermost surface of the epidermis by electron microscopy. We demonstrated for the first time that silver applied as nanoparticles coated with polyvinylpirrolidone is able to permeate the damaged skin in an in vitro diffusion cell system

Human skin wetness perception: psychophysical and neurophysiological bases

Science.gov (United States)

Filingeri, Davide; Havenith, George

2015-01-01

The ability to perceive thermal changes in the surrounding environment is critical for survival. However, sensing temperature is not the only factor among the cutaneous sensations to contribute to thermoregulatory responses in humans. Sensing skin wetness (i.e. hygrosensation) is also critical both for behavioral and autonomic adaptations. Although much has been done to define the biophysical role of skin wetness in contributing to thermal homeostasis, little is known on the neurophysiological mechanisms underpinning the ability to sense skin wetness. Humans are not provided with skin humidity receptors (i.e., hygroreceptors) and psychophysical studies have identified potential sensory cues (i.e. thermal and mechanosensory) which could contribute to sensing wetness. Recently, a neurophysiological model of human wetness sensitivity has been developed. In helping clarifying the peripheral and central neural mechanisms involved in sensing skin wetness, this model has provided evidence for the existence of a specific human hygrosensation strategy, which is underpinned by perceptual learning via sensory experience. Remarkably, this strategy seems to be shared by other hygroreceptor-lacking animals. However, questions remain on whether these sensory mechanisms are underpinned by specific neuromolecular pathways in humans. Although the first study on human wetness perception dates back to more than 100 years, it is surprising that the neurophysiological bases of such an important sensory feature have only recently started to be unveiled. Hence, to provide an overview of the current knowledge on human hygrosensation, along with potential directions for future research, this review will examine the psychophysical and neurophysiological bases of human skin wetness perception. PMID:27227008

Handheld skin printer: in situ formation of planar biomaterials and tissues.

Science.gov (United States)

Hakimi, Navid; Cheng, Richard; Leng, Lian; Sotoudehfar, Mohammad; Ba, Phoenix Qing; Bakhtyar, Nazihah; Amini-Nik, Saeid; Jeschke, Marc G; Günther, Axel

2018-05-15

We present a handheld skin printer that enables the in situ formation of biomaterial and skin tissue sheets of different homogeneous and architected compositions. When manually positioned above a target surface, the compact instrument (weight <0.8 kg) conformally deposits a biomaterial or tissue sheet from a microfluidic cartridge. Consistent sheet formation is achieved by coordinating the flow rates at which bioink and cross-linker solution are delivered, with the speed at which a pair of rollers actively translate the cartridge along the surface. We demonstrate compatibility with dermal and epidermal cells embedded in ionically cross-linkable biomaterials (e.g., alginate), and enzymatically cross-linkable proteins (e.g., fibrin), as well as their mixtures with collagen type I and hyaluronic acid. Upon rapid crosslinking, biomaterial and skin cell-laden sheets of consistent thickness, width and composition were obtained. Sheets deposited onto horizontal, agarose-coated surfaces were used for physical and in vitro characterization. Proof-of-principle demonstrations for the in situ formation of biomaterial sheets in murine and porcine excisional wound models illustrate the capacity of depositing onto inclined and compliant wound surfaces that are subject to respiratory motion. We expect the presented work will enable the in situ delivery of a wide range of different cells, biomaterials, and tissue adhesives, as well as the in situ fabrication of spatially organized biomaterials, tissues, and biohybrid structures.

Proteome Analysis of Human Sebaceous Follicle Infundibula Extracted from Healthy and Acne-Affected Skin

Science.gov (United States)

Bek-Thomsen, Malene; Lomholt, Hans B.; Scavenius, Carsten; Enghild, Jan J.; Brüggemann, Holger

2014-01-01

Acne vulgaris is a very common disease of the pilosebaceous unit of the human skin. The pathological processes of acne are not fully understood. To gain further insight sebaceous follicular casts were extracted from 18 healthy and 20 acne-affected individuals by cyanoacrylate-gel biopsies and further processed for mass spectrometry analysis, aiming at a proteomic analysis of the sebaceous follicular casts. Human as well as bacterial proteins were identified. Human proteins enriched in acne and normal samples were detected, respectively. Normal follicular casts are enriched in proteins such as prohibitins and peroxiredoxins which are involved in the protection from various stresses, including reactive oxygen species. By contrast, follicular casts extracted from acne-affected skin contained proteins involved in inflammation, wound healing and tissue remodeling. Among the most distinguishing proteins were myeloperoxidase, lactotransferrin, neutrophil elastase inhibitor and surprisingly, vimentin. The most significant biological process among all acne-enriched proteins was ‘response to a bacterium’. Identified bacterial proteins were exclusively from Propionibacterium acnes. The most abundant P. acnes proteins were surface-exposed dermatan sulphate adhesins, CAMP factors, and a so far uncharacterized lipase in follicular casts extracted from normal as well as acne-affected skin. This is a first proteomic study that identified human proteins together with proteins of the skin microbiota in sebaceous follicular casts. PMID:25238151

Quantitatively characterizing microstructural variations of skin tissues during ultraviolet radiation damaging process based on Mueller matrix polarimetry

Science.gov (United States)

Sheng, Wei; He, Honghui; Dong, Yang; Ma, Hui

2018-02-01

As one of the most fundamental features of light, polarization can be used to develop imaging techniques which can provide insight into the optical and structural properties of tissues. Especially, the Mueller matrix polarimetry is suitable to detect the changes in collagen and elastic fibres, which are the main compositions of skin tissue. Here we demonstrate a novel quantitative, non-contact and in situ technique to monitor the microstructural variations of skin tissue during ultraviolet radiation (UVR) induced photoaging based on Mueller matrix polarimetry. Specifically, we measure the twodimensional (2D) backscattering Mueller matrices of nude mouse skin samples, then calculate and analyze the Mueller matrix derived parameters during the skin photoaging and self-repairing processes. To induce three-day skin photoaging, the back skin of each mouse is irradiated with UVR (0.05J/cm2) for five minutes per day. After UVR, the microstructures of the nude mouse skin are damaged. During the process of UV damage, we measure the backscattering Mueller matrices of the mouse skin samples and examine the relationship between the Mueller matrix parameters and the microstructural variations of skin tissue quantitatively. The comparisons between the UVR damaged groups with and without sunscreens show that the Mueller matrix derived parameters are potential indicators for fibrous microstructure variation in skin tissue. The pathological examinations and Monte Carlo simulations confirm the relationship between the values of Mueller matrix parameters and the changes of fibrous structures. Combined with smart phones or wearable devices, this technique may have a good application prospect in the fields of cosmetics and dermatological health.

Xenobiotica-metabolizing enzymes in the skin of rat, mouse, pig, guinea pig, man, and in human skin models.

Science.gov (United States)

Oesch, F; Fabian, E; Landsiedel, Robert

2018-06-18

Studies on the metabolic fate of medical drugs, skin care products, cosmetics and other chemicals intentionally or accidently applied to the human skin have become increasingly important in order to ascertain pharmacological effectiveness and to avoid toxicities. The use of freshly excised human skin for experimental investigations meets with ethical and practical limitations. Hence information on xenobiotic-metabolizing enzymes (XME) in the experimental systems available for pertinent studies compared with native human skin has become crucial. This review collects available information of which-taken with great caution because of the still very limited data-the most salient points are: in the skin of all animal species and skin-derived in vitro systems considered in this review cytochrome P450 (CYP)-dependent monooxygenase activities (largely responsible for initiating xenobiotica metabolism in the organ which provides most of the xenobiotica metabolism of the mammalian organism, the liver) are very low to undetectable. Quite likely other oxidative enzymes [e.g. flavin monooxygenase, COX (cooxidation by prostaglandin synthase)] will turn out to be much more important for the oxidative xenobiotic metabolism in the skin. Moreover, conjugating enzyme activities such as glutathione transferases and glucuronosyltransferases are much higher than the oxidative CYP activities. Since these conjugating enzymes are predominantly detoxifying, the skin appears to be predominantly protected against CYP-generated reactive metabolites. The following recommendations for the use of experimental animal species or human skin in vitro models may tentatively be derived from the information available to date: for dermal absorption and for skin irritation esterase activity is of special importance which in pig skin, some human cell lines and reconstructed skin models appears reasonably close to native human skin. With respect to genotoxicity and sensitization reactive

Modeling skin cooling using optical windows and cryogens during laser induced hyperthermia in a multilayer vascularized tissue

International Nuclear Information System (INIS)

Singh, Rupesh; Das, Koushik; Okajima, Junnosuke; Maruyama, Shigenao; Mishra, Subhash C.

2015-01-01

This article deals with the spatial and the temporal evolution of tissue temperature during skin surface cooled laser induced hyperthermia. Three different skin surface cooling methodologies viz., optical window contact cooling, cryogenic spray cooling and cryogen cooled optical window contact cooling are considered. Sapphire, yttrium aluminum garnet, lithium tantalate, and magnesium oxide doped lithium niobate are the considered optical windows. The cryogens considered are liquid CO_2 and R1234yf. Heat transfer in the multilayer skin tissue embedded with thermally significant blood vessels pairs is modeled using the Pennes and Weinbaum–Jiji bioheat equations. Weinbaum–Jiji bioheat equation is used for the vascularized tissue. Laser transport in the tissue is modeled using the radiative transfer equation. Axial and radial (skin surface) temperature distributions for different combinations of optical windows and cryogens are analyzed. Liquid CO_2 cooled yttrium aluminum garnet is found to be the best surface cooling mechanism. - Highlights: • Skin surface cooled laser induced hyperthermia is studied. • A multi-layer 2-D cylindrical tissue geometry is considered. • Both Pennes and Weinbaum–Jiji bioheat models are considered. • Laser transport in the tissue is modeled using discrete ordinate method. • Results for 4 optical windows and 2 cryogens for skin cooling are presented.

Does human leukocyte elastase degrade intact skin elastin?

DEFF Research Database (Denmark)

Schmelzer, Christian E H; Jung, Michael C; Wohlrab, Johannes

2012-01-01

This study aimed to investigate the susceptibility of intact fibrillar human elastin to human leukocyte elastase and cathepsin G. Elastin is a vital protein of the extracellular matrix of vertebrates, and provides exceptional properties including elasticity and tensile strength to many tissues...... and organs, including the aorta, lung, cartilage, elastic ligaments and skin, and is thus critical for their long-term function. Mature elastin is an insoluble and extremely durable protein that undergoes very little turnover, but sustained exposure to proteases may lead to irreversible and severe damage......, and thus to functional loss of the elastic fiber network. Hence, it is a key issue to understand which enzymes actually initiate elastolysis under certain pathological conditions or during intrinsic aging. In this paper, we provide a complete workflow for isolation of pure and intact elastin from very...

Storage conditions of skin affect tissue structure and in vitro percutaneus penetration

DEFF Research Database (Denmark)

Nielsen, Jesper Bo; Bagatolli, Luis

2016-01-01

skin at -20oC causes structural changes in the upper Stratum Corneum observable with image techniques such as multiphoton excitation fluorescence microscopy. The presently available literature does, however, not support that the observed structural damage to the integrity is sufficient to cause...... structural changes in upper as well as deeper parts of Stratum Corneum. These more severe changes corresponds to significantly increased percutaneous penetration of chemicals applied to skin specimens stored at very low temperatures. Storage of human skin for later use in in vitro studies on percutaneous......For logistic and practical reasons it is difficult to perform in vitro studies on percutaneous penetration on fresh human skin obtained directly from surgery. Skin samples are therefore often kept frozen until use. The present chapter present the available literature on the topic. Storage of human...

Evaluation of Perfusion and Thermal Parameters of Skin Tissue Using Cold Provocation and Thermographic Measurements

Directory of Open Access Journals (Sweden)

Strąkowska Maria

2016-09-01

Full Text Available Measurement of the perfusion coefficient and thermal parameters of skin tissue using dynamic thermography is presented in this paper. A novel approach based on cold provocation and thermal modelling of skin tissue is presented. The measurement was performed on a person’s forearm using a special cooling device equipped with the Peltier module. The proposed method first cools the skin, and then measures the changes of its temperature matching the measurement results with a heat transfer model to estimate the skin perfusion and other thermal parameters. In order to assess correctness of the proposed approach, the uncertainty analysis was performed.

Skin color and tissue thickness effects on transmittance, reflectance, and skin temperature when using 635 and 808 nm lasers in low intensity therapeutics.

Science.gov (United States)

Souza-Barros, Leanna; Dhaidan, Ghaith; Maunula, Mikko; Solomon, Vaeda; Gabison, Sharon; Lilge, Lothar; Nussbaum, Ethne L

2018-04-01

To examine the role of skin color and tissue thickness on transmittance, reflectance, and skin heating using red and infrared laser light. Forty volunteers were measured for skin color and skin-fold thickness at a standardized site near the elbow. Transmittance, reflectance and skin temperature were recorded for energy doses of 2, 6, 9, and 12 Joules using 635 nm (36 mW) and 808 nm (40 mW) wavelength laser diodes with irradiances within American National Standards Institute safety guidelines (4.88 mm diameter, 0.192 W/cm 2 and 4.88 mm diameter, 0.214 W/cm 2 , respectively). The key factors affecting reflectance to an important degree were skin color and wavelength. However, the skin color effects were different for the two wavelengths: reflectance decreased for darker skin with a greater decrease for red light than near infrared light. Transmittance was greater using 808 nm compared with 635 nm. However, the effect was partly lost when the skin was dark rather than light, and was increasingly lost as tissue thickness increased. Dose had an increasing effect on temperature (0.7-1.6°C across the 6, 9, and 12 J doses); any effects of wavelength, skin color, and tissue thickness were insignificant compared to dose effects. Subjects themselves were not aware of the increased skin temperature. Transmittance and reflectance changes as a function of energy were very small and likely of no clinical significance. Absorption did not change with higher energy doses and increasing temperature. Skin color and skin thickness affect transmittance and reflectance of laser light and must be accounted for when selecting energy dose to ensure therapeutic effectiveness at the target tissue. Skin heating appears not to be a concern when using 635 and 808 nm lasers at energy doses of up to 12 J and irradiance within American National Standards Institute standards. Photobiomodulation therapy should never exceed the American National Standards Institute

Human cell transformation in the study of sunlight-induced cancers in the skin of man

International Nuclear Information System (INIS)

Sutherland, B.M.; Bennett, P.V.

1988-01-01

Human cell transformation provides a powerful approach to understanding - at the cellular and molecular levels - induction of cancers in the skin of man. A principal approach to this problem is the direct transformation of human skin cells by exposure to ultraviolet and/or near-UV radiation. The frequency of human cells transformed to anchorage independence increases with radiation exposure; the relative transforming efficiencies of different wavelengths implies that direct absorption by nucleic acids is a primary initial event. Partial reversal of potential transforming lesions by photoreactivation suggests that pyrimidine dimers, as well as other lesions, are important in UV transformation of human cells. Human cells can also be transformed by transfection with cloned oncogenes, or with DNAs from tumors or tumor cell lines. Cells treated by the transfection procedure (but without DNA) or cells transfected with DNAs from normal mammalian cells or tissues show only background levels of transformation. Human cells can be transformed to anchorage-independent growth by DNAs ineffective in transformation of NIH 3T3 cells (including most human skin cancers), permitting the analysis of oncogenic molecular changes even in tumor DNAs difficult or impossible to analyze in rodent cell systems. 29 refs.; 4 figs.; 1 table

The effect of keratinocytes on the biomechanical characteristics and pore microstructure of tissue engineered skin using deep dermal fibroblasts.

Science.gov (United States)

Varkey, Mathew; Ding, Jie; Tredget, Edward E

2014-12-01

Fibrosis affects most organs, it results in replacement of normal parenchymal tissue with collagen-rich extracellular matrix, which compromises tissue architecture and ultimately causes loss of function of the affected organ. Biochemical pathways that contribute to fibrosis have been extensively studied, but the role of biomechanical signaling in fibrosis is not clearly understood. In this study, we assessed the effect keratinocytes have on the biomechanical characteristics and pore microstructure of tissue engineered skin made with superficial or deep dermal fibroblasts in order to determine any biomaterial-mediated anti-fibrotic influences on tissue engineered skin. Tissue engineered skin with deep dermal fibroblasts and keratinocytes were found to be less stiff and contracted and had reduced number of myofibroblasts and lower expression of matrix crosslinking factors compared to matrices with deep fibroblasts alone. However, there were no such differences between tissue engineered skin with superficial fibroblasts and keratinocytes and matrices with superficial fibroblasts alone. Also, tissue engineered skin with deep fibroblasts and keratinocytes had smaller pores compared to those with superficial fibroblasts and keratinocytes; pore size of tissue engineered skin with deep fibroblasts and keratinocytes were not different from those matrices with deep fibroblasts alone. A better understanding of biomechanical characteristics and pore microstructure of tissue engineered skin may prove beneficial in promoting normal wound healing over pathologic healing. Copyright © 2014 Elsevier Ltd. All rights reserved.

Skin Bioprinting: Impending Reality or Fantasy?

Science.gov (United States)

Ng, Wei Long; Wang, Shuai; Yeong, Wai Yee; Naing, May Win

2016-09-01

Bioprinting provides a fully automated and advanced platform that facilitates the simultaneous and highly specific deposition of multiple types of skin cells and biomaterials, a process that is lacking in conventional skin tissue-engineering approaches. Here, we provide a realistic, current overview of skin bioprinting, distinguishing facts from myths. We present an in-depth analysis of both current skin bioprinting works and the cellular and matrix components of native human skin. We also highlight current limitations and achievements, followed by design considerations and a future outlook for skin bioprinting. The potential of bioprinting with converging opportunities in biology, material, and computational design will eventually facilitate the fabrication of improved tissue-engineered (TE) skin constructs, making bioprinting skin an impending reality. Copyright © 2016 Elsevier Ltd. All rights reserved.

A mechanics approach to the study of pressure sensitive adhesives and human skin for transdermal drug delivery applications

Science.gov (United States)

Taub, Marc Barry

Transdermal drug delivery is an alternative approach to the systemic delivery of pharmaceuticals where drugs are administered through the skin and absorbed percutaneously. This method of delivery offers several advantages over more traditional routes; most notably, the avoidance of the fast-pass metabolism of the liver and gut, the ability to offer controlled release rates, and the possibility for novel devices. Pressure sensitive adhesives (PSAs) are used to bond transdermal drug delivery devices to the skin because of their good initial and long-term adhesion, clean removability, and skin and drug compatibility. However, an understanding of the mechanics of adhesion to the dermal layer, together with quantitative and reproducible test methods for measuring adhesion, have been lacking. This study utilizes a mechanics-based approach to quantify the interfacial adhesion of PSAs bonded to selected substrates, including human dermal tissue. The delamination of PSA layers is associated with cavitation in the PSA followed by the formation of an extensive cohesive zone behind the debond tip. A quantitative metrology was developed to assess the adhesion and delamination of PSAs, such that it could be possible to easily distinguish between the adhesive characteristics of different PSA compositions and to provide a quantitative basis from which the reliability of adhesive layers bonded to substrates could be studied. A mechanics-based model was also developed to predict debonding in terms of the relevant energy dissipation mechanisms active during this process. As failure of transdermal devices may occur cohesively within the PSA layer, adhesively at the interface between the PSA and the skin, or cohesively between the corneocytes that comprise the outermost layer of the skin, it was also necessary to explore the mechanical and fracture properties of human skin. The out-of-plane delamination of corneocytes was studied by determining the strain energy release rate during

Genetically engineered tissue to screen for glycan function in tissue formation

DEFF Research Database (Denmark)

M., Adamopoulou; E.M., Pallesen; A., Levann

2017-01-01

engineered GlycoSkin tissue models can be used to study biological interactions involving glycan structure on lipids, or glycosaminoglycans. This engineering approach will allow us to investigate the functions of glycans in homeostasis and elucidate the role of glycans in normal epithelial formation....... We use genetic engineering with CRISPR/Cas9 combined with 3D organotypic skin models to examine how distinct glycans influence epithelial formation. We have performed knockout and knockin of more than 100 select genes in the genome of human immortalized human keratinocytes, enabling a systematic...... analysis of the impact of specific glycans in the formation and transformation of the human skin. The genetic engineered human skin models (GlycoSkin) was designed with and without all major biosynthetic pathways in mammalian glycan biosynthesis, including GalNAc-O-glycans, O-fucosylation, O...

Eyelid skin as a potential site for drug delivery to conjunctiva and ocular tissues.

Science.gov (United States)

See, Gerard Lee; Sagesaka, Ayano; Sugasawa, Satoko; Todo, Hiroaki; Sugibayashi, Kenji

2017-11-25

The feasibility of topical application onto the (lower) eyelid skin to deliver hydrophilic and lipophilic compounds into the conjunctiva and ocular tissues was evaluated by comparing with conventional eye drop application. Skin permeation and the concentration of several model compounds, and skin impedance were determined utilizing eyelid skin from hairless rats, as well as abdominal skin in the same animals for comparison. In vitro static diffusion cells were used to assess the skin permeation in order to provide key insights into the relationship between the skin sites and drugs. The obtained results revealed that drug permeation through the eyelid skin was much higher than that through abdominal skin regardless of the drug lipophilicity. Specifically, diclofenac sodium salt and tranilast exhibited approximately 6-fold and 11-fold higher permeability coefficients, respectively, through eyelid skin compared with abdominal skin. Histomorphological evaluation and in vivo distribution of model fluorescent dyes were also examined in the conjunctiva and skin after eyelid administration by conventional microscope and confocal laser scanning microscope analyses. The result revealed that eyelid skin has a thinner stratum corneum, thereby showing lower impedance, which could be the reason for the higher drug permeation through eyelid skin. Comparative evaluation of lipophilic and hydrophilic model compounds administered via the eyelid skin over 8h revealed stronger fluorescence intensity in the skin and surrounding tissues compared with eye drop administration. These results suggested that the (lower) eyelid skin is valuable as a prospective site for ophthalmic medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

Disinfection of human skin allografts in tissue banking: a systematic review report.

Science.gov (United States)

Johnston, C; Callum, J; Mohr, J; Duong, A; Garibaldi, A; Simunovic, N; Ayeni, O R

2016-12-01

The use of skin allografts to temporarily replace lost or damaged skin is practiced worldwide. Naturally occurring contamination can be present on skin or can be introduced at recovery or during processing. This contamination can pose a threat to allograft recipients. Bacterial culture and disinfection of allografts are mandated, but the specific practices and methodologies are not dictated by standards. A systematic review of literature from three databases found 12 research articles that evaluated bioburden reduction processes of skin grafts. The use of broad spectrum antibiotics and antifungal agents was the most frequently identified disinfection method reported demonstrating reductions in contamination rates. It was determined that the greatest reduction in the skin allograft contamination rates utilized 0.1 % peracetic acid or 25 kGy of gamma irradiation at lower temperatures.

Fractionation parameters for human tissues and tumors

International Nuclear Information System (INIS)

Thames, H.D.; Turesson, I.; Bogaert, W. van den

1989-01-01

Time-dose factors such as fractionation sensitivity (α/β) can sometimes be estimated from clinical data, when there is a wide variation in dose, fraction size, treatment time, etc. This report summarizes estimates of fractionation parameters derived from clinical results. Consistent with the animal data, α/β is higher for acutely responding than for late-responding normal tissues. While many human tumors seem to be characterized by high α/β values, there are exceptions (e.g. melanomas). Repair kinetics may be slower in human than in rodent skin and mucosa, but there are no hard and fast estimates of the repair halftime. Regeneration in head and neck tumors is equivalent to a daily dose of 1 Gy or less, while in the mucosa it is equivalent to approximately 1.8 Gy/day. (author)

Metabolism of skin-absorbed resveratrol into its glucuronized form in mouse skin.

Directory of Open Access Journals (Sweden)

Itsuo Murakami

Full Text Available Resveratrol (RESV is a plant polyphenol, which is thought to have beneficial metabolic effects in laboratory animals as well as in humans. Following oral administration, RESV is immediately catabolized, resulting in low bioavailability. This study compared RESV metabolites and their tissue distribution after oral uptake and skin absorption. Metabolomic analysis of various mouse tissues revealed that RESV can be absorbed and metabolized through skin. We detected sulfated and glucuronidated RESV metabolites, as well as dihydroresveratrol. These metabolites are thought to have lower pharmacological activity than RESV. Similar quantities of most RESV metabolites were observed 4 h after oral or skin administration, except that glucuronidated RESV metabolites were more abundant in skin after topical RESV application than after oral administration. This result is consistent with our finding of glucuronidated RESV metabolites in cultured skin cells. RESV applied to mouse ears significantly suppressed inflammation in the TPA inflammation model. The skin absorption route could be a complementary, potent way to achieve therapeutic effects with RESV.

Multivariate Models for Prediction of Human Skin Sensitization ...

Science.gov (United States)

One of the lnteragency Coordinating Committee on the Validation of Alternative Method's (ICCVAM) top priorities is the development and evaluation of non-animal approaches to identify potential skin sensitizers. The complexity of biological events necessary to produce skin sensitization suggests that no single alternative method will replace the currently accepted animal tests. ICCVAM is evaluating an integrated approach to testing and assessment based on the adverse outcome pathway for skin sensitization that uses machine learning approaches to predict human skin sensitization hazard. We combined data from three in chemico or in vitro assays - the direct peptide reactivity assay (DPRA), human cell line activation test (h-CLAT) and KeratinoSens TM assay - six physicochemical properties and an in silico read-across prediction of skin sensitization hazard into 12 variable groups. The variable groups were evaluated using two machine learning approaches , logistic regression and support vector machine, to predict human skin sensitization hazard. Models were trained on 72 substances and tested on an external set of 24 substances. The six models (three logistic regression and three support vector machine) with the highest accuracy (92%) used: (1) DPRA, h-CLAT and read-across; (2) DPRA, h-CLAT, read-across and KeratinoSens; or (3) DPRA, h-CLAT, read-across, KeratinoSens and log P. The models performed better at predicting human skin sensitization hazard than the murine

Modelling glucose and water dynamics in human skin

NARCIS (Netherlands)

Groenendaal, W.; Schmidt, K.H.; Basum, von G.; Riel, van N.A.W.; Hilbers, P.A.J.

2008-01-01

Background: Glucose is heterogeneously distributed in the different physiological compartments in the human skin. Therefore, for the development of a noninvasive measurement method, both a good quantification of the different compartments of human skin and an understanding of glucose transport

Skin immune sentinels in health and disease.

Science.gov (United States)

Nestle, Frank O; Di Meglio, Paola; Qin, Jian-Zhong; Nickoloff, Brian J

2009-10-01

Human skin and its immune cells provide essential protection of the human body from injury and infection. Recent studies reinforce the importance of keratinocytes as sensors of danger through alert systems such as the inflammasome. In addition, newly identified CD103(+) dendritic cells are strategically positioned for cross-presentation of skin-tropic pathogens and accumulating data highlight a key role of tissue-resident rather than circulating T cells in skin homeostasis and pathology. This Review focuses on recent progress in dissecting the functional role of skin immune cells in skin disease.

Tissue banking for management of nuclear casualties

International Nuclear Information System (INIS)

Singh, Rita

2014-01-01

The proliferation of nuclear material and technology has made the acquisition and adversarial use more probable than ever. Devastating medical consequences would follow a nuclear detonation due to the thermal, blast and radiation effects of the weapon. Atomic explosions at Hiroshima and Nagasaki demonstrated the human agonies on vast scale. A full range of medical modalities are required to decrease the morbidity and mortality as a result of the use of nuclear weapons. Biological tissues from human donor like bone, skin, amniotic membrane and other soft tissues can be used for repair or reconstruction of the injured part of the body. Tissues from human donor can be processed and banked for orthopaedic, spinal, trauma and other surgical procedures. Processed tissues can be provided by the tissue banks and can be of great assistance in the treatment of injuries due to the nuclear weapon. The use of allograft tissue avoids the donor site morbidity and reduces the operating time, expense and trauma associated with the acquisition of autografts. Further, allografts have the added advantage of being available in large quantities. This has led to a global increase in allogeneic transplantation and development of tissue banking. The aim of the tissue bank is to provide a wide range of processed biological tissues free from any transmissible disease, that help to restore the growth and function of the damaged tissues. Skin dressings or skin substitutes like allograft skin, xenograft skin and amniotic membrane can be used for the treatment of thermal burns and radiation induced skin injuries. Bone allografts can be used for reconstructive approaches to the skeletal system. Tissue banking would thus ensure health care to the military personnel and population following a nuclear detonation. (author)

Characterization of RNA isolated from eighteen different human tissues: results from a rapid human autopsy program.

Science.gov (United States)

Walker, Douglas G; Whetzel, Alexis M; Serrano, Geidy; Sue, Lucia I; Lue, Lih-Fen; Beach, Thomas G

2016-09-01

Many factors affect the integrity of messenger RNA from human autopsy tissues including postmortem interval (PMI) between death and tissue preservation and the pre-mortem agonal and disease states. In this communication, we describe RNA isolation and characterization of 389 samples from 18 different tissues from elderly donors who were participants in a rapid whole-body autopsy program located in Sun City, Arizona ( www.brainandbodydonationprogram.org ). Most tissues were collected within a PMI of 2-6 h (median 3.15 h; N = 455), but for this study, tissue from cases with longer PMIs (1.25-29.25 h) were included. RNA quality was assessed by RNA integrity number (RIN) and total yield (ng RNA/mg tissue). RIN correlated with PMI for heart (r = -0.531, p = 0.009) and liver (r = -558, p = 0.0017), while RNA yield correlated with PMI for colon (r = -485, p = 0.016) and skin (r = -0.460, p = 0.031). RNAs with the lowest integrity were from skin and cervix where 22.7 and 31.4 % of samples respectively failed to produce intact RNA; by contrast all samples from esophagus, lymph node, jejunum, lung, stomach, submandibular gland and kidney produced RNA with measurable RINs. Expression levels in heart RNA of 4 common housekeeping normalization genes showed significant correlations of Ct values with RIN, but only one gene, glyceraldehyde-3 phosphate dehydrogenase, showed a correlation of Ct with PMI. There were no correlations between RIN values obtained for liver, adrenal, cervix, esophagus and lymph node and those obtained from corresponding brain samples. We show that high quality RNA can be produced from most human autopsy tissues, though with significant differences between tissues and donors. The RNA stability and yield did not depend solely on PMI; other undetermined factors are involved, but these do not include the age of the donor.

Utilization of reconstructed cultured human skin models as an alternative skin for permeation studies of chemical compounds

OpenAIRE

Kano, Satoshi; 藤堂, 浩明; 杉江, 謙一; 藤本, 英哲; 中田, 圭一; 徳留, 嘉寛; 橋本, フミ惠; 杉林, 堅次

2010-01-01

Two reconstructed human skin models, EpiskinSM and EpiDermTM, have been approved as alternative membranes for skin corrosive/irritation experiments due to their close correlation with animal skin. Such reconstructed human skin models were evaluated as alternative membranes for skin permeation experiments. Seven drugs with different lipophilicities and almost the same molecular weight were used as test penetrants. Relationships were investigated between permeability coefficients (P values) of ...

Evaluation of effects of platelet-rich plasma on human facial skin.

Science.gov (United States)

Yuksel, Esra Pancar; Sahin, Gokhan; Aydin, Fatma; Senturk, Nilgun; Turanli, Ahmet Yasar

2014-10-01

Platelet-rich plasma (PRP) has been used for rapid healing and tissue regeneration in many fields of medicine. This study was conducted to evaluate the effects of PRP application procedure on human facial skin. PRP was applied thrice at 2-week intervals on the face of ten healthy volunteers. It was applied to individual's forehead, malar area, and jaw by a dermaroller, and injected using a 27-gauge injector into the wrinkles of crow's feet. Participants were asked to grade on a scale from 0 to 5 for general appearance, skin firmness-sagging, wrinkle state and pigmentation disorder of their own face before each PRP procedure and 3 months after the last PRP procedure. While volunteers were evaluating their own face, they were also assessed by three different dermatologists at the same time by the same five-point scale. There was statistically significant difference regarding the general appearance, skin firmness-sagging and wrinkle state according to the grading scale of the patients before and after three PRP applications. Whereas there was only statistically significant difference for the skin firmness-sagging according to the assessment of the dermatologists. PRP application could be considered as an effective procedure for facial skin rejuvenation.

Evaluation of a Silicone Membrane as an Alternative to Human Skin for Determining Skin Permeation Parameters of Chemical Compounds.

Science.gov (United States)

Uchida, Takashi; Yakumaru, Masafumi; Nishioka, Keisuke; Higashi, Yoshihiro; Sano, Tomohiko; Todo, Hiroaki; Sugibayashi, Kenji

2016-01-01

We evaluated the effectiveness of a silicone membrane as an alternative to human skin using the skin permeation parameters of chemical compounds. An in vitro permeation study using 15 model compounds was conducted, and permeation parameters comprising permeability coefficient (P), diffusion parameter (DL(-2)), and partition parameter (KL) were calculated from each permeation profile. Significant correlations were obtained in log P, log DL(-2), and log KL values between the silicone membrane and human skin. DL(-2) values of model compounds, except flurbiprofen, in the silicone membrane were independent of the lipophilicity of the model compounds and were 100-fold higher than those in human skin. For antipyrine and caffeine, which are hydrophilic, KL values in the silicone membrane were 100-fold lower than those in human skin, and P values, calculated as the product of a DL(-2) and KL, were similar. For lipophilic compounds, such as n-butyl paraben and flurbiprofen, KL values for silicone were similar to or 10-fold higher than those in human skin, and P values for silicone were 100-fold higher than those in human skin. Furthermore, for amphiphilic compounds with log Ko/w values from 0.5 to 3.5, KL values in the silicone membrane were 10-fold lower than those in human skin, and P values for silicone were 10-fold higher than those in human skin. The silicone membrane was useful as a human skin alternative in an in vitro skin permeation study. However, depending on the lipophilicity of the model compounds, some parameters may be over- or underestimated.

Unexpected complication associated with balneotherapy: Skin and soft tissue infection

Science.gov (United States)

Alım, Bülent; Bostancı, Fahrettin; Servi, M. Alperen; Ćetinel, Sinan; Bingöl, M. Ozan

2017-04-01

Balneotherapy cure is an ongoing process, but patients can benefit most when cure is complete. For these reason, patients should be closely monitored and necessary precautions should be taken in terms of the complications that may occur in order to prevent the interruption or discontinuation of balneotherapy. Here, we wanted to represent a case that developed left leg soft tissue infection during the application of balneotherapy and because of this reason we stopped the balneotherapy As a result, when balneotherapy is planned for patients with risk factors such as diabetes and obesity, frequent examination of the skin and the application of skin moisturizers will be beneficial to prevent itching and skin dryness.

Generation of human-induced pluripotent stem cells from burn patient-derived skin fibroblasts using a non-integrative method.

Science.gov (United States)

Fu, Shangfeng; Ding, Jianwu; Liu, Dewu; Huang, Heping; Li, Min; Liu, Yang; Tu, Longxiang; Liu, Deming

2018-01-01

Patient specific induced pluripotent stem cells (iPSCs) have been recognized as a possible source of cells for skin tissue engineering. They have the potential to greatly benefit patients with large areas of burned skin or skin defects. However, the integration virus-based reprogramming method is associated with a high risk of genetic mutation and mouse embryonic fibroblast feeder-cells may be a pollutant. In the present study, human skin fibroblasts (HSFs) were successfully harvested from patients with burns and patient-specific iPSCs were generated using a non-integration method with a feeder-free approach. The octamer-binding transcription factor 4 (OCT4), sex-determining region Y box 2 (SOX2) and NANOG transcription factors were delivered using Sendai virus vectors. iPSCs exhibited representative human embryonic stem cell-like morphology and proliferation characteristics. They also expressed pluripotent markers, including OCT4, NANOG, SOX2, TRA181, stage-specific embryonic antigen 4 and TRA-160, and exhibited a normal karyotype. Teratoma and embryoid body formation revealed that iPSCs were able to differentiate into cells of all three germ layers in vitro and in vivo. The results of the present study demonstrate that HSFs derived from patients with burns, may be reprogrammed into stem cells with pluripotency, which provides a basis for cell‑based skin tissue engineering in the future.

DNA damage and repair in human skin in situ

International Nuclear Information System (INIS)

Sutherland, B.M.; Gange, R.W.; Freeman, S.E.; Sutherland, J.C.

1987-01-01

Understanding the molecular and cellular origins of sunlight-induced skin cancers in man requires knowledge of the damages inflicted on human skin during sunlight exposure, as well as the ability of cells in skin to repair or circumvent such damage. Although repair has been studied extensively in procaryotic and eucaryotic cells - including human cells in culture - there are important differences between repair by human skin cells in culture and human skin in situ: quantitative differences in rates of repair, as well as qualitative differences, including the presence or absence of repair mechanisms. Quantitation of DNA damage and repair in human skin required the development of new approaches for measuring damage at low levels in nanogram quantities of non-radioactive DNA. The method allows for analysis of multiple samples and the resulting data should be related to behavior of the DNA molecules by analytic expressions. Furthermore, it should be possible to assay a variety of lesions using the same methodology. The development of new analysis methods, new technology, and new biochemical probes for the study of DNA damage and repair are described. 28 refs., 4 figs

DNA damage and repair in human skin in situ

Energy Technology Data Exchange (ETDEWEB)

Sutherland, B.M.; Gange, R.W.; Freeman, S.E.; Sutherland, J.C.

1987-01-01

Understanding the molecular and cellular origins of sunlight-induced skin cancers in man requires knowledge of the damages inflicted on human skin during sunlight exposure, as well as the ability of cells in skin to repair or circumvent such damage. Although repair has been studied extensively in procaryotic and eucaryotic cells - including human cells in culture - there are important differences between repair by human skin cells in culture and human skin in situ: quantitative differences in rates of repair, as well as qualitative differences, including the presence or absence of repair mechanisms. Quantitation of DNA damage and repair in human skin required the development of new approaches for measuring damage at low levels in nanogram quantities of non-radioactive DNA. The method allows for analysis of multiple samples and the resulting data should be related to behavior of the DNA molecules by analytic expressions. Furthermore, it should be possible to assay a variety of lesions using the same methodology. The development of new analysis methods, new technology, and new biochemical probes for the study of DNA damage and repair are described. 28 refs., 4 figs.

Variation of mutational burden in healthy human tissues suggests non-random strand segregation and allows measuring somatic mutation rates.

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Werner, Benjamin; Sottoriva, Andrea

2018-06-01

The immortal strand hypothesis poses that stem cells could produce differentiated progeny while conserving the original template strand, thus avoiding accumulating somatic mutations. However, quantitating the extent of non-random DNA strand segregation in human stem cells remains difficult in vivo. Here we show that the change of the mean and variance of the mutational burden with age in healthy human tissues allows estimating strand segregation probabilities and somatic mutation rates. We analysed deep sequencing data from healthy human colon, small intestine, liver, skin and brain. We found highly effective non-random DNA strand segregation in all adult tissues (mean strand segregation probability: 0.98, standard error bounds (0.97,0.99)). In contrast, non-random strand segregation efficiency is reduced to 0.87 (0.78,0.88) in neural tissue during early development, suggesting stem cell pool expansions due to symmetric self-renewal. Healthy somatic mutation rates differed across tissue types, ranging from 3.5 × 10-9/bp/division in small intestine to 1.6 × 10-7/bp/division in skin.

Variation of mutational burden in healthy human tissues suggests non-random strand segregation and allows measuring somatic mutation rates.

Directory of Open Access Journals (Sweden)

Benjamin Werner

2018-06-01

Full Text Available The immortal strand hypothesis poses that stem cells could produce differentiated progeny while conserving the original template strand, thus avoiding accumulating somatic mutations. However, quantitating the extent of non-random DNA strand segregation in human stem cells remains difficult in vivo. Here we show that the change of the mean and variance of the mutational burden with age in healthy human tissues allows estimating strand segregation probabilities and somatic mutation rates. We analysed deep sequencing data from healthy human colon, small intestine, liver, skin and brain. We found highly effective non-random DNA strand segregation in all adult tissues (mean strand segregation probability: 0.98, standard error bounds (0.97,0.99. In contrast, non-random strand segregation efficiency is reduced to 0.87 (0.78,0.88 in neural tissue during early development, suggesting stem cell pool expansions due to symmetric self-renewal. Healthy somatic mutation rates differed across tissue types, ranging from 3.5 × 10-9/bp/division in small intestine to 1.6 × 10-7/bp/division in skin.

Soft tissue augmentation in skin of color: market growth, available fillers, and successful techniques.

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Burgess, Cheryl M

2007-01-01

In recent years, people of color have become an increasingly important market force for the cosmetics industry. Product lines have been expanded to accommodate a broader spectrum of skin colors and marketing strategies have been specialized in order to target specific ethnic populations. In addition, it is predicted that people with pigmented skin will eventually comprise a majority of the domestic and international population during the 21st century. Not surprisingly, people of color are increasingly seeking out products and procedures to fight the effects of aging, including an increase in surgical and nonsurgical cosmetic procedures. Among nonsurgical procedures, soft tissue augmentation has experienced dramatic growth. Today, clinicians are performing more and more of these procedures in people of color. As a result of these shifts in the cosmetics industry, clinicians performing soft tissue augmentation require increased expertise in the treatment of ethnic skin. This article reviews the important differences that exist between the appearance of the aging faces of Caucasians and people of color. In addition, soft tissue augmentation strategies and injection techniques that are specific to skin of color are discussed.

Tumor necrosis factor-α-accelerated degradation of type I collagen in human skin is associated with elevated matrix metalloproteinase (MMP)-1 and MMP-3 ex vivo

DEFF Research Database (Denmark)

Ågren, Magnus S; Schnabel, Reinhild; Christensen, Lise H

2015-01-01

Tumor necrosis factor (TNF)-α induces matrix metalloproteinases (MMPs) that may disrupt skin integrity. We have investigated the effects and mechanisms of exogenous TNF-α on collagen degradation by incubating human skin explants in defined serum-free media with or without TNF-α (10ng/ml) in the a......Tumor necrosis factor (TNF)-α induces matrix metalloproteinases (MMPs) that may disrupt skin integrity. We have investigated the effects and mechanisms of exogenous TNF-α on collagen degradation by incubating human skin explants in defined serum-free media with or without TNF-α (10ng...... tissue-derived collagenolytic activity with TNF-α exposure was blocked by neutralizing MMP-1 monoclonal antibody and was not due to down-regulation of tissue inhibitor of metalloproteinase-1. TNF-α increased production (pendogenous MMP-1...

Assessment of penetration of quantum dots through in vitro and in vivo human skin using the human skin equivalent model and the tape stripping method

International Nuclear Information System (INIS)

Jeong, Sang Hoon; Kim, Jae Hwan; Yi, Sang Min; Lee, Jung Pyo; Kim, Jin Ho; Sohn, Kyung Hee; Park, Kui Lea; Kim, Meyoung-Kon; Son, Sang Wook

2010-01-01

Quantum dots (QDs) are rapidly emerging as an important class of nanoparticles (NPs) with potential applications in medicine. However, little is known about penetration of QDs through human skin. This study investigated skin penetration of QDs in both in vivo and in vitro human skin. Using the tape stripping method, this study demonstrates for the first time that QDs can actually penetrate through the stratum corneum (SC) of human skin. Transmission electron microscope (TEM) and energy diverse X-ray (EDX) analysis showed accumulation of QDs in the SC of a human skin equivalent model (HSEM) after dermal exposure to QDs. These findings suggest possible transdermal absorption of QDs after dermal exposure over a relatively long period of time.

YAP regulates the expression of Hoxa1 and Hoxc13 in mouse and human oral and skin epithelial tissues.

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Liu, Ming; Zhao, Shuangyun; Lin, Qingjie; Wang, Xiu-Ping

2015-04-01

Yes-associated protein (YAP) is a Hippo signaling transcriptional coactivator that plays pivotal roles in stem cell proliferation, organ size control, and tumor development. The downstream targets of YAP have been shown to be highly context dependent. In this study, we used the embryonic mouse tooth germ as a tool to search for the downstream targets of YAP in ectoderm-derived tissues. Yap deficiency in the dental epithelium resulted in a small tooth germ with reduced epithelial cell proliferation. We compared the gene expression profiles of embryonic day 14.5 (E14.5) Yap conditional knockout and YAP transgenic mouse tooth germs using transcriptome sequencing (RNA-Seq) and further confirmed the differentially expressed genes using real-time PCR and in situ hybridization. We found that YAP regulates the expression of Hoxa1 and Hoxc13 in oral and dental epithelial tissues as well as in the epidermis of skin during embryonic and adult stages. Sphere formation assay suggested that Hoxa1 and Hoxc13 are functionally involved in YAP-regulated epithelial progenitor cell proliferation, and chromatin immunoprecipitation (ChIP) assay implies that YAP may regulate Hoxa1 and Hoxc13 expression through TEAD transcription factors. These results provide mechanistic insights into abnormal YAP activities in mice and humans. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Skin and the non-human human

DEFF Research Database (Denmark)

Rösing, Lilian Munk

2013-01-01

The article puts forward an aesthetic and psychoanalytic analysis of Titian's painting, The Flaying of Marsyas, arguing that the painting is a reflection on the human subject as a being constituted by skin and by a core of non-humanity. The analysis is partly an answer to Melanie Hart's (2007) ar...... of the 'Muselmann', and Anton Ehrenzweig's psychoanalytic theory of artistic creation. Whereas Hart is focusing on form and colour, I also turn my attention towards the texture of the painting....

Skin Sensitive Difference of Human Body Sections under Clothing-Smirnov Test of Skin Surface Temperatures' Dynamic Changing

Institute of Scientific and Technical Information of China (English)

LI Jun; WU Hai-yan; WANG Yun-yi

2004-01-01

Skin sensitive difference of human body sections under clothing is the theoretic foundation of thermal insulation clothing design.By a new method of researching on clothing comfort perception,the skin temperature live changing procedure of human body sections affected by the same cold stimulation is inspected.Furthermore with the Smirnov test the skin temperatures dynamic changing patterns of main human body sections are obtained.

Laser induced autofluorescence for diagnosis of non-melanoma skin cancer

Science.gov (United States)

Drakaki, E.; Makropoulou, M.; Serafetinides, A. A.; Merlemis, N.; Kalatzis, I.; Sianoudis, I. A.; Batsi, O.; Christofidou, E.; Stratigos, A. J.; Katsambas, A. D.; Antoniou, Ch.

2015-01-01

Non melanoma skin cancer is one of the most frequent malignant tumors among humans. A non-invasive technique, with high sensitivity and high specificity, would be the most suitable method for basal cell carcinoma (BCC) or other malignancies diagnostics, instead of the well established biopsy and histopathology examination. In the last decades, a non-invasive, spectroscopic diagnostic method was introduced, the laser induced fluorescence (LIF), which could generate an image contrast between different states of skin tissue. The noninvasiveness consists in that this biophotonic method do not require tissue sample excision, what is necessary in histopathology characterization and biochemical analysis of the skin tissue samples, which is worldwide used as an evaluation gold standard. The object of this study is to establish the possibilities of a relatively portable system for laser induced skin autofluorescence to differentiate malignant from nonmalignant skin lesions. Unstained human skin samples, excised from humans undergoing biopsy examination, were irradiated with a Nd:YAG-3ω laser (λ=355 nm, 6 ns), used as an excitation source for the autofluorescence measurements. A portable fiber-based spectrometer was used to record fluorescence spectra of the sites of interest. The ex vivo results, obtained with this spectroscopic technique, were correlated with the histopathology results. After the analysis of the fluorescence spectra of almost 60 skin tissue areas, we developed an algorithm to distinguish different types of malignant lesions, including inflammatory areas. Optimization of the data analysis and potential use of LIF spectroscopy with 355 nm Nd:YAG laser excitation of tissue autofluorescence for clinical applications are discussed.

Development of human skin equivalents mimicking skin aging : contrast between papillary and reticular fibroblasts as a lead

NARCIS (Netherlands)

Janson, D.

2017-01-01

This thesis describes the development of human skin equivalents that show characteristics of skin aging. The type of skin equivalent used was a fibroblast derived matrix equivalent, in which the dermal compartment is generated by fibroblasts and thus is fully of human origin. Two strategies are

Electrospun Poly(lactic acid-co-glycolic acid) Scaffolds for Skin Tissue Engineering

Science.gov (United States)

Kumbar, Sangamesh G.; Nukavarapu, Syam Prasad; James, Roshan; Nair, Lakshmi S.; Laurencin, Cato T.

2008-01-01

Electrospun fiber matrices composed of scaffolds of varying fiber diameters were investigated for potential application of severe skin loss. Few systematic studies have been performed to examine the effect of varying fiber diameter electrospun fiber matrices for skin regeneration. The present study reports the fabrication of poly[lactic acid-co-glycolic acid] (PLAGA) matrices with fiber diameters of 150–225, 200–300, 250–467, 500–900, 600–1200, 2500–3000 and 3250–6000 nm via electrospinning. All fiber matrices found to have a tensile modulus from 39.23 ± 8.15 to 79.21 ± 13.71 MPa which falls in the range for normal human skin. Further, the porous fiber matrices have porosity between 38–60 % and average pore diameters between 10–14µm. We evaluated the efficacy of these biodegradable fiber matrices as skin substitutes by seeding them with human skin fibroblasts (hSF). Human skin fibroblasts acquired a well spread morphology and showed significant progressive growth on fiber matrices in the 350–1100 nm diameter range. Collagen type III gene expression was significantly up-regulated in hSF seeded on matrices with fiber diameters in the range of 350–1100 nm. Based on the need, the proposed fiber skin substitutes can be successfully fabricated and optimized for skin fibroblast attachment and growth. PMID:18639927

The role of subcutaneous tissue stiffness on microneedle performance in a representative in vitro model of skin.

Science.gov (United States)

Moronkeji, K; Todd, S; Dawidowska, I; Barrett, S D; Akhtar, R

2017-11-10

There has been growing interest in the mechanical behaviour of skin due to the rapid development of microneedle devices for drug delivery applications into skin. However, most in vitro experimentation studies that are used to evaluate microneedle performance do not consider the biomechanical properties of skin or that of the subcutaneous layers. In this study, a representative experimental model of skin was developed which was comprised of subcutaneous and muscle mimics. Neonatal porcine skin from the abdominal and back regions was used, with gelatine gels of differing water content (67, 80, 88 and 96%) to represent the subcutaneous tissue, and a type of ballistic gelatine, Perma-Gel®, as a muscle mimic. Dynamic nanoindentation was used to characterize the mechanical properties of each of these layers. A custom-developed impact test rig was used to apply dense polymethylmethacrylate (PMMA) microneedles to the skin models in a controlled and repeatable way with quantification of the insertion force and velocity. Image analysis methods were used to measure penetration depth and area of the breach caused by microneedle penetration following staining and optical imaging. The nanoindentation tests demonstrated that the tissue mimics matched expected values for subcutaneous and muscle tissue, and that the compliance of the subcutaneous mimics increased linearly with water content. The abdominal skin was thinner and less stiff as compared to back skin. The maximum force decreased with gel water content in the abdominal skin but not in the back skin. Overall, larger and deeper perforations were found in the skin models with increasing water content. These data demonstrate the importance of subcutaneous tissue on microneedle performance and the need for representative skin models in microneedle technology development. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Multivariate Models for Prediction of Human Skin Sensitization Hazard

Science.gov (United States)

Strickland, Judy; Zang, Qingda; Paris, Michael; Lehmann, David M.; Allen, David; Choksi, Neepa; Matheson, Joanna; Jacobs, Abigail; Casey, Warren; Kleinstreuer, Nicole

2016-01-01

One of ICCVAM’s top priorities is the development and evaluation of non-animal approaches to identify potential skin sensitizers. The complexity of biological events necessary to produce skin sensitization suggests that no single alternative method will replace the currently accepted animal tests. ICCVAM is evaluating an integrated approach to testing and assessment based on the adverse outcome pathway for skin sensitization that uses machine learning approaches to predict human skin sensitization hazard. We combined data from three in chemico or in vitro assays—the direct peptide reactivity assay (DPRA), human cell line activation test (h-CLAT), and KeratinoSens™ assay—six physicochemical properties, and an in silico read-across prediction of skin sensitization hazard into 12 variable groups. The variable groups were evaluated using two machine learning approaches, logistic regression (LR) and support vector machine (SVM), to predict human skin sensitization hazard. Models were trained on 72 substances and tested on an external set of 24 substances. The six models (three LR and three SVM) with the highest accuracy (92%) used: (1) DPRA, h-CLAT, and read-across; (2) DPRA, h-CLAT, read-across, and KeratinoSens; or (3) DPRA, h-CLAT, read-across, KeratinoSens, and log P. The models performed better at predicting human skin sensitization hazard than the murine local lymph node assay (accuracy = 88%), any of the alternative methods alone (accuracy = 63–79%), or test batteries combining data from the individual methods (accuracy = 75%). These results suggest that computational methods are promising tools to effectively identify potential human skin sensitizers without animal testing. PMID:27480324

First genomic survey of human skin fungal diversity

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Fungal infections of the skin affect 29 million people in the United States. In the first study of human fungal skin diversity, National Institutes of Health researchers sequenced the DNA of fungi that thrive at different skin sites of healthy adults to d

Human skin is protected by four functionally and phenotypically discrete populations of resident and recirculating memory T cells

Science.gov (United States)

Watanabe, Rei; Gehad, Ahmed; Yang, Chao; Campbell, Laura; Teague, Jessica E.; Schlapbach, Christoph; Elco, Christopher; Huang, Victor; Matos, Tiago R.; Kupper, Thomas S.; Clark, Rachael A.

2015-01-01

The skin of an adult human contains approximately 20 billion memory T cells. Epithelial barrier tissues are infiltrated by a combination of resident and recirculating T cells in mice but the relative proportions and functional activities of resident versus recirculating T cells have not been evaluated in human skin. We discriminated resident from recirculating T cells in human engrafted mice and lymphoma patients using alemtuzumab, a medication that depletes recirculating T cells from skin, and then analyzed these T cell populations in healthy human skin. All non-recirculating resident memory T cells (TRM) expressed CD69, but the majority were CD4+, CD103− and located in the dermis, in contrast to studies in mice. Both CD4+ and CD8+ CD103+ TRM were enriched in the epidermis, had potent effector functions and had a limited proliferative capacity compared to CD103− TRM. TRM of both types had more potent effector functions than recirculating T cells. Induction of CD103 on human T cells was enhanced by keratinocyte contact, depended on TGFβ and was independent of T cell keratinocyte adhesive interactions. We observed two distinct populations of recirculating T cells, CCR7+/L-selectin+ central memory T cells (TCM) and CCR7+/L-selectin− T cells, which we term migratory memory T cells (TMM). Circulating skin-tropic TMM were intermediate in cytokine production between TCM and effector memory T cells. In patients with cutaneous T cell lymphoma, malignant TCM and TMM induced distinct inflammatory skin lesions and TMM were depleted more slowly from skin after alemtuzumab, suggesting TMM may recirculate more slowly. In summary, human skin is protected by four functionally distinct populations of T cells, two resident and two recirculating, with differing territories of migration and distinct functional activities. PMID:25787765

Relating friction on the human skin to the hydration and temperature of the skin

NARCIS (Netherlands)

Veijgen, N.K.; Masen, Marc Arthur; van der Heide, Emile

2013-01-01

The human skin is constantly in interaction with materials and products. Therefore, skin friction is relevant to all people. In the literature, the frictional properties of the skin have been linked to a large variety of variables, like age, gender and hydration. The present study compares the data

Morphofunctional evaluation of human skin preserved in glycerol and exposed to gamma radiation: a study in athymic mice

International Nuclear Information System (INIS)

Bringel, Fabiana de Andrade

2011-01-01

Extensive skin lesions expose the body to damaging agents, which makes spontaneous regeneration difficult and, in many cases, leads patient to death. In such cases, if there are no donating areas for autograft, allografts can be used. In this type of graft, tissue is processed in tissue banks, where it can be subjected to radiosterilization. According to in vitro studies, gamma radiation, in doses higher than 25 kGy, induces alterations in skin preserved in glycerol at 85%, reducing the tensile strength of irradiated tissue. Clinical observation also suggests faster integration of such graft with the receptors tissue. In order to assess if the alterations observed in vitro, would compromise in vivo use, transplants of human tissue, irradiated or not, were performed in Nude mice. The skin of the mice was subjected to macroscopic analysis, optical coherence tomography imaging, histological and biomechanical assays. It was possible to conclude that grafts irradiated with 25 kGy promoted greater initial contraction, without alteration of the final dimensions of the repair area, also displaying a faster closing of the wound. Moreover, the use of irradiated grafts (25 and 50 kGy) enabled the formation of a more organized healing process without significant effects on biomechanical properties. (author)

Hydrodynamic gene delivery in human skin using a hollow microneedle device.

Science.gov (United States)

Dul, M; Stefanidou, M; Porta, P; Serve, J; O'Mahony, C; Malissen, B; Henri, S; Levin, Y; Kochba, E; Wong, F S; Dayan, C; Coulman, S A; Birchall, J C

2017-11-10

Microneedle devices have been proposed as a minimally invasive delivery system for the intradermal administration of nucleic acids, both plasmid DNA (pDNA) and siRNA, to treat localised disease or provide vaccination. Different microneedle types and application methods have been investigated in the laboratory, but limited and irreproducible levels of gene expression have proven to be significant challenges to pre-clinical to clinical progression. This study is the first to explore the potential of a hollow microneedle device for the delivery and subsequent expression of pDNA in human skin. The regulatory approved MicronJet600® (MicronJet hereafter) device was used to deliver reporter plasmids (pCMVβ and pEGFP-N1) into viable excised human skin. Exogenous gene expression was subsequently detected at multiple locations that were distant from the injection site but within the confines of the bleb created by the intradermal bolus. The observed levels of gene expression in the tissue are at least comparable to that achieved by the most invasive microneedle application methods e.g. lateral application of a microneedle. Gene expression was predominantly located in the epidermis, although also evident in the papillary dermis. Optical coherence tomography permitted real time visualisation of the sub-surface skin architecture and, unlike a conventional intradermal injection, MicronJet administration of a 50μL bolus appears to create multiple superficial microdisruptions in the papillary dermis and epidermis. These were co-localised with expression of the pCMVβ reporter plasmid. We have therefore shown, for the first time, that a hollow microneedle device can facilitate efficient and reproducible gene expression of exogenous naked pDNA in human skin using volumes that are considered to be standard for intradermal administration, and postulate a hydrodynamic effect as the mechanism of gene delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

Skin cancer risk in autoimmune connective tissue diseases.

Science.gov (United States)

Kostaki, D; Antonini, A; Peris, K; Fargnoli, M C

2014-10-01

Cutaneous malignancies have been significantly associated with autoimmune connective tissue diseases (ACTDs). This review focuses on the current state of knowledge on skin cancer risk in the most prevalent ACTDs in dermatology including lupus erythematosus, scleroderma, dermatomyositis and Sjögren syndrome. Potential pathogenetic mechanisms for the association between ACTDs and malignancy involve disease-related impairment of immune system, sustained cutaneous inflammation, drug-associated immune suppression and increased susceptibility to acquired viral infections. An additional causal role might be played by environmental factors such as UV exposure and smoking. The occurrence of skin cancer can have a profound impact on the already compromised quality of life of ACTD patients. Therefore, effective screening and monitoring strategies are essential for ACTD patients as early detection and prompt therapeutic intervention can reduce morbidity and mortality in these patients.

Approach to skin and soft tissue infections in non-HIV immunocompromised hosts.

Science.gov (United States)

Burke, Victoria E; Lopez, Fred A

2017-08-01

Skin and soft tissue infections are frequent contributors to morbidity and mortality in the immunocompromised host. This article reviews the changing epidemiology and clinical manifestations of the most common cutaneous pathogens in non-HIV immunocompromised hosts, including patients with solid organ transplants, stem cell transplants, solid tumors, hematologic malignancies, and receiving chronic immunosuppressive therapy for inflammatory disorders. Defects in the innate or adaptive immune response can predispose the immunocompromised host to certain cutaneous infections in a predictive fashion. Cutaneous lesions in patients with neutrophil defects are commonly due to bacteria, Candida, or invasive molds. Skin lesions in patients with cellular or humoral immunodeficiencies can be due to encapsulated bacteria, Nocardia, mycobacteria, endemic fungal infections, herpesviruses, or parasites. Skin lesions may reflect primary inoculation or, more commonly, disseminated infection. Tissue samples for microscopy, culture, and histopathology are critical to making an accurate diagnosis given the nonspecific and heterogeneous appearance of these skin lesions due to a blunted immune response. As the population of non-HIV immunosuppressed hosts expands with advances in medical therapies, the frequency and variety of cutaneous diseases in these hosts will increase.

Increased Susceptibility of Humanized NSG Mice to Panton-Valentine Leukocidin and Staphylococcus aureus Skin Infection.

Directory of Open Access Journals (Sweden)

Ching Wen Tseng

Full Text Available Staphylococcus aureus is a leading cause of skin and soft-tissue infections worldwide. Mice are the most commonly used animals for modeling human staphylococcal infections. However a supra-physiologic S. aureus inoculum is required to establish gross murine skin pathology. Moreover, many staphylococcal factors, including Panton-Valentine leukocidin (PVL elaborated by community-associated methicillin-resistant S. aureus (CA-MRSA, exhibit selective human tropism and cannot be adequately studied in mice. To overcome these deficiencies, we investigated S. aureus infection in non-obese diabetic (NOD/severe combined immune deficiency (SCID/IL2rγnull (NSG mice engrafted with human CD34+ umbilical cord blood cells. These "humanized" NSG mice require one to two log lower inoculum to induce consistent skin lesions compared with control mice, and exhibit larger cutaneous lesions upon infection with PVL+ versus isogenic PVL- S. aureus. Neutrophils appear important for PVL pathology as adoptive transfer of human neutrophils alone to NSG mice was sufficient to induce dermonecrosis following challenge with PVL+ S. aureus but not PVL- S. aureus. PMX53, a human C5aR inhibitor, blocked PVL-induced cellular cytotoxicity in vitro and reduced the size difference of lesions induced by the PVL+ and PVL- S. aureus, but PMX53 also reduced recruitment of neutrophils and exacerbated the infection. Overall, our findings establish humanized mice as an important translational tool for the study of S. aureus infection and provide strong evidence that PVL is a human virulence factor.

Dynamic skin deformation simulation using musculoskeletal model and soft tissue dynamics

Institute of Scientific and Technical Information of China (English)

Akihiko Murai; Q. Youn Hong; Katsu Yamane; Jessica K. Hodgins

2017-01-01

Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin deformations that must move appropriately for the character design. In this paper, we present an algorithm that generates natural, dynamic, and detailed skin deformation (movement and jiggle) from joint angle data sequences. The algorithm has two steps: identification of parameters for a quasi-static muscle deformation model, and simulation of skin deformation. In the identification step, we identify the model parameters using a musculoskeletal model and a short sequence of skin deformation data captured via a dense marker set. The simulation step first uses the quasi-static muscle deformation model to obtain the quasi-static muscle shape at each frame of the given motion sequence (slow jump). Dynamic skin deformation is then computed by simulating the passive muscle and soft tissue dynamics modeled as a mass–spring–damper system. Having obtained the model parameters, we can simulate dynamic skin deformations for subjects with similar body types from new motion data. We demonstrate our method by creating skin deformations for muscle co-contraction and external impacts from four different behaviors captured as skeletal motion capture data. Experimental results show that the simulated skin deformations are quantitatively and qualitatively similar to measured actual skin deformations.

Dynamic skin deformation simulation using musculoskeletal model and soft tissue dynamics

Institute of Scientific and Technical Information of China (English)

Akihiko Murai; Q.Youn Hong; Katsu Yamane; Jessica K.Hodgins

2017-01-01

Deformation of skin and muscle is essential for bringing an animated character to life. This deformation is difficult to animate in a realistic fashion using traditional techniques because of the subtlety of the skin deformations that must move appropriately for the character design. In this paper, we present an algorithm that generates natural, dynamic, and detailed skin deformation(movement and jiggle) from joint angle data sequences. The algorithm has two steps: identification of parameters for a quasi-static muscle deformation model, and simulation of skin deformation. In the identification step, we identify the model parameters using a musculoskeletal model and a short sequence of skin deformation data captured via a dense marker set. The simulation step first uses the quasi-static muscle deformation model to obtain the quasi-static muscle shape at each frame of the given motion sequence(slow jump). Dynamic skin deformation is then computed by simulating the passive muscle and soft tissue dynamics modeled as a mass–spring–damper system. Having obtained the model parameters, we can simulate dynamic skin deformations for subjects with similar body types from new motion data. We demonstrate our method by creating skin deformations for muscle co-contraction and external impacts from four different behaviors captured as skeletal motion capture data. Experimental results show that the simulated skin deformations are quantitatively and qualitatively similar to measured actual skin deformations.

Marine-derived biological macromolecule-based biomaterials for wound healing and skin tissue regeneration.

Science.gov (United States)

Chandika, Pathum; Ko, Seok-Chun; Jung, Won-Kyo

2015-01-01

Wound healing is a complex biological process that depends on the wound condition, the patient's health, and the physicochemical support given through external materials. The development of bioactive molecules and engineered tissue substitutes to provide physiochemical support to enhance the wound healing process plays a key role in advancing wound-care management. Thus, identification of ideal molecules in wound treatment is still in progress. The discovery of natural products that contain ideal molecules for skin tissue regeneration has been greatly advanced by exploration of the marine bioenvironment. Consequently, tremendously diverse marine organisms have become a great source of numerous biological macromolecules that can be used to develop tissue-engineered substitutes with wound healing properties. This review summarizes the wound healing process, the properties of macromolecules from marine organisms, and the involvement of these molecules in skin tissue regeneration applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Radiation sterilization of skin allograft

International Nuclear Information System (INIS)

Kairiyama, E.; Horak, C.; Spinosa, M.; Pachado, J.; Schwint, O.

2009-01-01

In the treatment of burns or accidental loss of skin, cadaveric skin allografts provide an alternative to temporarily cover a wounded area. The skin bank facility is indispensable for burn care. The first human skin bank was established in Argentina in 1989; later, 3 more banks were established. A careful donor selection is carried out according to the national regulation in order to prevent transmissible diseases. As cadaveric human skin is naturally highly contaminated, a final sterilization is necessary to reach a sterility assurance level (SAL) of 10 -6 . The sterilization dose for 106 batches of processed human skin was determined on the basis of the Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control (2004) and ISO 11137-2 (2006). They ranged from 17.6 to 33.4 kGy for bioburdens of >10-162.700 CFU/100 cm 2 . The presence of Gram negative bacteria was checked for each produced batch. From the analysis of the experimental results, it was observed that the bioburden range was very wide and consequently the estimated sterilization doses too. If this is the case, the determination of a tissue-specific dose per production batch is necessary to achieve a specified requirement of SAL. Otherwise if the dose of 25 kGy is preselected, a standardized method for substantiation of this dose should be done to confirm the radiation sterilization process.

Radiation sterilization of skin allograft

Science.gov (United States)

Kairiyama, E.; Horak, C.; Spinosa, M.; Pachado, J.; Schwint, O.

2009-07-01

In the treatment of burns or accidental loss of skin, cadaveric skin allografts provide an alternative to temporarily cover a wounded area. The skin bank facility is indispensable for burn care. The first human skin bank was established in Argentina in 1989; later, 3 more banks were established. A careful donor selection is carried out according to the national regulation in order to prevent transmissible diseases. As cadaveric human skin is naturally highly contaminated, a final sterilization is necessary to reach a sterility assurance level (SAL) of 10 -6. The sterilization dose for 106 batches of processed human skin was determined on the basis of the Code of Practice for the Radiation Sterilization of Tissue Allografts: Requirements for Validation and Routine Control (2004) and ISO 11137-2 (2006). They ranged from 17.6 to 33.4 kGy for bioburdens of >10-162.700 CFU/100 cm 2. The presence of Gram negative bacteria was checked for each produced batch. From the analysis of the experimental results, it was observed that the bioburden range was very wide and consequently the estimated sterilization doses too. If this is the case, the determination of a tissue-specific dose per production batch is necessary to achieve a specified requirement of SAL. Otherwise if the dose of 25 kGy is preselected, a standardized method for substantiation of this dose should be done to confirm the radiation sterilization process.

Safety of radiofrequency treatment over human skin previously injected with medium-term injectable soft-tissue augmentation materials: a controlled pilot trial.

Science.gov (United States)

Alam, Murad; Levy, Ross; Pajvani, Urvi; Pavjani, Urvi; Ramierez, James A; Guitart, Joan; Veen, Heather; Gladstone, Hayes B

2006-03-01

Several soft-tissue augmentation materials are now available for reduction of nasolabial fold creases and perioral rhytides. Nasolabial folds and perioral rhytides can also be improved by skin tightening delivered by non-ablative radiofrequency (RF) treatment. The purpose of this study was to assess the safety of RF treatment over skin areas recently injected with medium-term injectable soft-tissue augmentation materials. Five subjects were assigned to the experimental arm (augmentation materials plus RF) and one to the control arm (augmentation materials alone). Each subject received injections of 0.3 mL of hyaluronic acid derivative (Restylane) and calcium hydroxylapatite (Radiesse) 3 cm apart on the upper inner arm. Two weeks later, two non-overlapping passes of RF (Thermage ThermaCool TC) were delivered at 63.5 setting with medium-fast 1.5 cm2 tip over injected sites in all of the experimental subjects. Punch skin biopsies were obtained 3 days later from each of the two injection sites on each subject. Light microscopy and digital photomicrographs obtained at low, medium, and high power showed no difference between filler materials in experimental and control subjects. In both cases filler was evident at the deep dermal-subcutaneous junction. Nodule formation, foreign body extravasation, or hemorrhage/clot was not observed grossly or histologically. Subjects and physicians did not report any difference in signs and symptoms between the experimental and control arms. Slightly increased transitory pain was noted when RF was delivered over filler versus over normal skin. Applying RF treatment over the same area 2 weeks after deep dermal injection with hyaluronic acid derivatives or calcium hydroxylapatite does not appear to cause gross morphological changes in the filler material or surrounding skin. Further studies with different parameters are necessary to confirm these findings. 2006 Wiley-Liss, Inc.

Low-level lasers affect uncoupling protein gene expression in skin and skeletal muscle tissues

International Nuclear Information System (INIS)

Canuto, K S; Sergio, L P S; Mencalha, A L; Fonseca, A S; Paoli, F

2016-01-01

Wavelength, frequency, power, fluence, and emission mode determine the photophysical, photochemical, and photobiological responses of biological tissues to low-level lasers. Free radicals are involved in these responses acting as second messengers in intracellular signaling processes. Irradiated cells present defenses against these chemical species to avoid unwanted effects, such as uncoupling proteins (UCPs), which are part of protective mechanisms and minimize the effects of free radical generation in mitochondria. In this work UCP2 and UCP3 mRNA gene relative expression in the skin and skeletal muscle tissues of Wistar rats exposed to low-level red and infrared lasers was evaluated. Samples of the skin and skeletal muscle tissue of Wistar rats exposed to low-level red and infrared lasers were withdrawn for total RNA extraction, cDNA synthesis, and the evaluation of gene expression by quantitative polymerase chain reaction. UCP2 and UCP3 mRNA expression was differently altered in skin and skeletal muscle tissues exposed to lasers in a wavelength-dependent effect, with the UCP3 mRNA expression dose-dependent. Alteration on UCP gene expression could be part of the biostimulation effect and is necessary to make cells exposed to red and infrared low-level lasers more resistant or capable of adapting in damaged tissues or diseases. (paper)

A robust approach to identifying tissue-specific gene expression regulatory variants using personalized human induced pluripotent stem cells.

Directory of Open Access Journals (Sweden)

Je-Hyuk Lee

2009-11-01

Full Text Available Normal variation in gene expression due to regulatory polymorphisms is often masked by biological and experimental noise. In addition, some regulatory polymorphisms may become apparent only in specific tissues. We derived human induced pluripotent stem (iPS cells from adult skin primary fibroblasts and attempted to detect tissue-specific cis-regulatory variants using in vitro cell differentiation. We used padlock probes and high-throughput sequencing for digital RNA allelotyping and measured allele-specific gene expression in primary fibroblasts, lymphoblastoid cells, iPS cells, and their differentiated derivatives. We show that allele-specific expression is both cell type and genotype-dependent, but the majority of detectable allele-specific expression loci remains consistent despite large changes in the cell type or the experimental condition following iPS reprogramming, except on the X-chromosome. We show that our approach to mapping cis-regulatory variants reduces in vitro experimental noise and reveals additional tissue-specific variants using skin-derived human iPS cells.

Modeling ancient Egyptian mummification on fresh human tissue: macroscopic and histological aspects.

Science.gov (United States)

Papageorgopoulou, Christina; Shved, Natallia; Wanek, Johann; Rühli, Frank J

2015-06-01

Many studies have been concerned with the ancient Egyptian mummification method; nevertheless, little effort has been made to explore it experimentally. The goal of this study is to apply evidence-based diagnostic criteria and state-of-the art methodology in order to improve knowledge on soft tissues preservation and postmortem alterations. Two human lower limbs (LL) from a female donor were (1) "naturally" mummified by dry heat and (2) artificially in natron. At specific time intervals a macroscopic and radiological examination of the LL was performed and skin and muscle samples were taken for histological and biomolecular analysis. Temperature, humidity, pH, and weight of the LL were systematically measured. The mummification by dry heat was stopped after 7 days due to unexpected lack of mummification progress. The mummification in natron was completed successfully after 208 days. The humidity, the external temperature, and the pH were proven with Pearson correlation and principal component analysis as important factors for the mummification process. The steady removal of water from the tissues through the natron has prevented the putrefaction. This is also evident in the absence of bacteria or fungi through the microbiological analysis. The histological analysis revealed very good preservation of the skin and the muscle tissues. In the muscular sample certain degree of structural disintegration can be seen, particularly affecting the epimysium whilst in the skin samples the epidermis, especially the stratum corneum, is mostly affected. The samples show better preservation compared with ancient Egyptian sections and other mummified tissues from historic or forensic context. © 2015 Wiley Periodicals, Inc.

Resonance Raman Spectroscopic Evaluation of Skin Carotenoids as a Biomarker of Carotenoid Status for Human Studies

Science.gov (United States)

Mayne, Susan T.; Cartmel, Brenda; Scarmo, Stephanie; Jahns, Lisa; Ermakov, Igor V.; Gellermann, Werner

2013-01-01

Resonance Raman Spectroscopy (RRS) is a non-invasive method that has been developed to assess carotenoid status in human tissues including human skin in vivo. Skin carotenoid status has been suggested as a promising biomarker for human studies. This manuscript describes research done relevant to the development of this biomarker, including its reproducibility, validity, feasibility for use in field settings, and factors that affect the biomarker such as diet, smoking, and adiposity. Recent studies have evaluated the response of the biomarker to controlled carotenoid interventions, both supplement-based and dietary [e.g., provision of a high-carotenoid fruit and vegetable (F/V)-enriched diet], demonstrating consistent response to intervention. The totality of evidence supports the use of skin carotenoid status as an objective biomarker of F/V intake, although in the cross-sectional setting, diet explains only some of the variation in this biomarker. However, this limitation is also a strength in that skin carotenoids may effectively serve as an integrated biomarker of health, with higher status reflecting greater F/V intake, lack of smoking, and lack of adiposity. Thus, this biomarker holds promise as both a health biomarker and an objective indicator of F/V intake, supporting its further development and utilization for medical and public health purposes. PMID:23823930

Black tattoos entail substantial uptake of genotoxicpolycyclic aromatic hydrocarbons (PAH) in human skin and regional lymph nodes.

Science.gov (United States)

Lehner, Karin; Santarelli, Francesco; Vasold, Rudolf; Penning, Randolph; Sidoroff, Alexis; König, Burkhard; Landthaler, Michael; Bäumler, Wolfgang

2014-01-01

Hundreds of millions of people worldwide have tattoos, which predominantly contain black inks consisting of soot products like Carbon Black or polycyclic aromatic hydrocarbons (PAH). We recently found up to 200 μg/g of PAH in commercial black inks. After skin tattooing, a substantial part of the ink and PAH should be transported to other anatomical sites like the regional lymph nodes. To allow a first estimation of health risk, we aimed to extract and quantify the amount of PAH in black tattooed skin and the regional lymph nodes of pre-existing tattoos. Firstly, we established an extraction method by using HPLC-DAD technology that enables the quantification of PAH concentrations in human tissue. After that, 16 specimens of human tattooed skin and corresponding regional lymph nodes were included in the study. All skin specimen and lymph nodes appeared deep black. The specimens were digested and tested for 20 different PAH at the same time.PAH were found in twelve of the 16 tattooed skin specimens and in eleven regional lymph nodes. The PAH concentration ranged from 0.1-0.6 μg/cm2 in the tattooed skin and 0.1-11.8 μg/g in the lymph nodes. Two major conclusions can be drawn from the present results. Firstly, PAH in black inks stay partially in skin or can be found in the regional lymph nodes. Secondly, the major part of tattooed PAH had disappeared from skin or might be found in other organs than skin and lymph nodes. Thus, beside inhalation and ingestion, tattooing has proven to be an additional, direct and effective route of PAH uptake into the human body.

Black tattoos entail substantial uptake of genotoxicpolycyclic aromatic hydrocarbons (PAH in human skin and regional lymph nodes.

Directory of Open Access Journals (Sweden)

Karin Lehner

Full Text Available Hundreds of millions of people worldwide have tattoos, which predominantly contain black inks consisting of soot products like Carbon Black or polycyclic aromatic hydrocarbons (PAH. We recently found up to 200 μg/g of PAH in commercial black inks. After skin tattooing, a substantial part of the ink and PAH should be transported to other anatomical sites like the regional lymph nodes. To allow a first estimation of health risk, we aimed to extract and quantify the amount of PAH in black tattooed skin and the regional lymph nodes of pre-existing tattoos. Firstly, we established an extraction method by using HPLC-DAD technology that enables the quantification of PAH concentrations in human tissue. After that, 16 specimens of human tattooed skin and corresponding regional lymph nodes were included in the study. All skin specimen and lymph nodes appeared deep black. The specimens were digested and tested for 20 different PAH at the same time.PAH were found in twelve of the 16 tattooed skin specimens and in eleven regional lymph nodes. The PAH concentration ranged from 0.1-0.6 μg/cm2 in the tattooed skin and 0.1-11.8 μg/g in the lymph nodes. Two major conclusions can be drawn from the present results. Firstly, PAH in black inks stay partially in skin or can be found in the regional lymph nodes. Secondly, the major part of tattooed PAH had disappeared from skin or might be found in other organs than skin and lymph nodes. Thus, beside inhalation and ingestion, tattooing has proven to be an additional, direct and effective route of PAH uptake into the human body.

An in vitro human skin test for assessing sensitization potential.

Science.gov (United States)

Ahmed, S S; Wang, X N; Fielding, M; Kerry, A; Dickinson, I; Munuswamy, R; Kimber, I; Dickinson, A M

2016-05-01

Sensitization to chemicals resulting in an allergy is an important health issue. The current gold-standard method for identification and characterization of skin-sensitizing chemicals was the mouse local lymph node assay (LLNA). However, for a number of reasons there has been an increasing imperative to develop alternative approaches to hazard identification that do not require the use of animals. Here we describe a human in-vitro skin explant test for identification of sensitization hazards and the assessment of relative skin sensitizing potency. This method measures histological damage in human skin as a readout of the immune response induced by the test material. Using this approach we have measured responses to 44 chemicals including skin sensitizers, pre/pro-haptens, respiratory sensitizers, non-sensitizing chemicals (including skin-irritants) and previously misclassified compounds. Based on comparisons with the LLNA, the skin explant test gave 95% specificity, 95% sensitivity, 95% concordance with a correlation coefficient of 0.9. The same specificity and sensitivity were achieved for comparison of results with published human sensitization data with a correlation coefficient of 0.91. The test also successfully identified nickel sulphate as a human skin sensitizer, which was misclassified as negative in the LLNA. In addition, sensitizers and non-sensitizers identified as positive or negative by the skin explant test have induced high/low T cell proliferation and IFNγ production, respectively. Collectively, the data suggests the human in-vitro skin explant test could provide the basis for a novel approach for characterization of the sensitizing activity as a first step in the risk assessment process. Copyright © 2015 John Wiley & Sons, Ltd.

Spectroscopic techniques in the study of human tissues and their components. Part I: IR spectroscopy.

Science.gov (United States)

Olsztyńska-Janus, Sylwia; Szymborska-Małek, Katarzyna; Gąsior-Głogowska, Marlena; Walski, Tomasz; Komorowska, Małgorzata; Witkiewicz, Wojciech; Pezowicz, Celina; Kobielarz, Magdalena; Szotek, Sylwia

2012-01-01

Among the currently used methods of monitoring human tissues and their components many types of research are distinguished. These include spectroscopic techniques. The advantage of these techniques is the small amount of sample required, the rapid process of recording the spectra, and most importantly in the case of biological samples - preparation of tissues is not required. In this work, vibrational spectroscopy: ATR-FTIR and Raman spectroscopy will be used. Studies are carried out on tissues: tendons, blood vessels, skin, red blood cells and biological components: amino acids, proteins, DNA, plasma, and deposits.

Tissue responses to fractional transient heating with sinusoidal heat flux condition on skin surface.

Science.gov (United States)

Ezzat, Magdy A; El-Bary, Alaa A; Al-Sowayan, Noorah S

2016-10-01

A fractional model of Bioheat equation for describing quantitatively the thermal responses of skin tissue under sinusoidal heat flux conditions on skin surface is given. Laplace transform technique is used to obtain the solution in a closed form. The resulting formulation is applied to one-dimensional application to investigate the temperature distribution in skin with instantaneous surface heating for different cases. According to the numerical results and its graphs, conclusion about the fractional bioheat transfer equation has been constructed. Sensitivity analysis is performed to explore the thermal effects of various control parameters on tissue temperature. The comparisons are made with the results obtained in the case of the absence of time-fractional order. © 2016 Japanese Society of Animal Science. © 2016 Japanese Society of Animal Science.

Photoreactivation in bacteria and in skin

International Nuclear Information System (INIS)

Sutherland, B.M.

1981-01-01

In many procaryotic and eucaryotic cells, photoreactivating enzyme mediates light-dependent repair of UV-induced damage: the enzyme binds to a pyrimidine dimer in DNA, and, on absorption of a photon (300-600 nm), specifically monomerizes the dimer, thus repairing the DNA. Photoreactivating enzyme has been found in human tissues and human cells in culture; human cells in culture can photoreactivate cellular dimers, and can mediate photoreactivation of Herpes (human fibroblasts) and Epstein-Barr virus (human leukocytes). Measurements of pyrimidine dimer formation and repair in human skin indicate that detectable numbers of dimers are formed at 1 minimal erythemal dose, that the dimers are rapidly removed in skin kept in the absence of light, and they are more rapidly removed when the skin is exposed to visible light

Water vapour loss measurements on human skin.

NARCIS (Netherlands)

Valk, Petrus Gerardus Maria van der

1984-01-01

In this thesis, the results of a series of investigations into the barrier function of human skin are presented. In these investigations, the barrier function was assessed by water vapour loss measurements of the skin using a method based on gradient estimation.... Zie: Summary and conclusions

Functional electrospun fibers for the treatment of human skin wounds.

Science.gov (United States)

Wang, Jing; Windbergs, Maike

2017-10-01

Wounds are trauma induced defects of the human skin involving a multitude of endogenous biochemical events and cellular reactions of the immune system. The healing process is extremely complex and affected by the patient's physiological conditions, potential implications like infectious pathogens and inflammation as well as external factors. Due to increasing incidence of chronic wounds and proceeding resistance of infection pathogens, there is a strong need for effective therapeutic wound care. In this context, electrospun fibers with diameters in the nano- to micrometer range gain increasing interest. While resembling the structure of the native human extracellular matrix, such fiber mats provide physical and mechanical protection (including protection against bacterial invasion). At the same time, the fibers allow for gas exchange and prevent occlusion of the wound bed, thus facilitating wound healing. In addition, drugs can be incorporated within such fiber mats and their release can be adjusted by the material and dimensions of the individual fibers. The review gives a comprehensive overview about the current state of electrospun fibers for therapeutic application on skin wounds. Different materials as well as fabrication techniques are introduced including approaches for incorporation of drugs into or drug attachment onto the fiber surface. Against the background of wound pathophysiology and established therapy approaches, the therapeutic potential of electrospun fiber systems is discussed. A specific focus is set on interactions of fibers with skin cells/tissues as well as wound pathogens and strategies to modify and control them as key aspects for developing effective wound therapeutics. Further, advantages and limitations of controlled drug delivery from fiber mats to skin wounds are discussed and a future perspective is provided. Copyright © 2017 Elsevier B.V. All rights reserved.

Human skin is protected by four functionally and phenotypically discrete populations of resident and recirculating memory T cells

NARCIS (Netherlands)

Watanabe, Rei; Gehad, Ahmed; Yang, Chao; Scott, Laura L.; Teague, Jessica E.; Schlapbach, Christoph; Elco, Christopher P.; Huang, Victor; Matos, Tiago R.; Kupper, Thomas S.; Clark, Rachael A.

2015-01-01

The skin of an adult human contains about 20 billion memory T cells. Epithelial barrier tissues are infiltrated by a combination of resident and recirculating T cells in mice, but the relative proportions and functional activities of resident versus recirculating T cells have not been evaluated in

Modeling the behavior of human body tissues on penetration

Science.gov (United States)

Conci, A.; Brazil, A. L.; Popovici, D.; Jiga, G.; Lebon, F.

2018-02-01

Several procedures in medicine (such as anesthesia, injections, biopsies and percutaneous treatments) involve a needle insertion. Such procedures operate without vision of the internal involved areas. Physicians and anesthetists rely on manual (force and tactile) feedback to guide their movements, so a number of medical practice is strongly based on manual skill. In order to be expert in the execution of such procedures the medical students must practice a number of times, but before practice in a real patient they must be trained in some place and a virtual environment, using Virtual Reality (VR) or Augmented Reality (AR) is the best possible solution for such training. In a virtual environment the success of user practices is improved by the addition of force output using haptic device to improve the manual sensations in the interactions between user and computer. Haptic devices enable simulate the physical restriction of the diverse tissues and force reactions to movements of operator hands. The trainees can effectively "feel" the reactions to theirs movements and receive immediate feedback from the actions executed by them in the implemented environment. However, in order to implement such systems, the tissue reaction to penetration and cutting must be modeled. A proper model must emulate the physical sensations of the needle action in the skin, fat, muscle, and so one, as if it really done in a patient that is as they are holding a real needle and feeling each tissue resistance when inserting it through the body. For example an average force value for human skin puncture is 6.0 N, it is 2.0 N for subcutaneous fat tissue and 4.4 N for muscles: this difference of sensations to penetration of each layers trespassed by the needle makes possible to suppose the correct position inside the body. This work presents a model for tissues before and after the cutting that with proper assumptions of proprieties can model any part of human body. It was based on experiments

Polymer scaffolds with no skin-effect for tissue engineering applications fabricated by thermally induced phase separation

International Nuclear Information System (INIS)

Kasoju, Naresh; Kubies, Dana; Sedlačík, Tomáš; Kumorek, Marta M.; Rypáček, František; Janoušková, Olga; Koubková, Jana

2016-01-01

Thermally induced phase separation (TIPS) based methods are widely used for the fabrication of porous scaffolds for tissue engineering and related applications. However, formation of a less-/non-porous layer at the scaffold’s outer surface at the air–liquid interface, often known as the skin-effect, restricts the cell infiltration inside the scaffold and therefore limits its efficacy. To this end, we demonstrate a TIPS-based process involving the exposure of the just quenched poly(lactide-co-caprolactone):dioxane phases to the pure dioxane for a short time while still being under the quenching strength, herein after termed as the second quenching (2Q). Scanning electron microscopy, mercury intrusion porosimetry and contact angle analysis revealed a direct correlation between the time of 2Q and the gradual disappearance of the skin, followed by the widening of the outer pores and the formation of the fibrous filaments over the surface, with no effect on the internal pore architecture and the overall porosity of scaffolds. The experiments at various quenching temperatures and polymer concentrations revealed the versatility of 2Q in removing the skin. In addition, the in vitro cell culture studies with the human primary fibroblasts showed that the scaffolds prepared by the TIPS based 2Q process, with the optimal exposure time, resulted in a higher cell seeding and viability in contrast to the scaffolds prepared by the regular TIPS. Thus, TIPS including the 2Q step is a facile, versatile and innovative approach to fabricate the polymer scaffolds with a skin-free and fully open porous surface morphology for achieving a better cell response in tissue engineering and related applications. (paper)

Chemical ecology of interactions between human skin microbiota and mosquitoes

NARCIS (Netherlands)

Verhulst, N.O.; Takken, W.; Dicke, M.; Schraa, G.; Smallegange, R.C.

2010-01-01

Microbiota on the human skin plays a major role in body odour production. The human microbial and chemical signature displays a qualitative and quantitative correlation. Genes may influence the chemical signature by shaping the composition of the microbiota. Recent studies on human skin microbiota,

QSAR models of human data can enrich or replace LLNA testing for human skin sensitization

OpenAIRE

Alves, Vinicius M.; Capuzzi, Stephen J.; Muratov, Eugene; Braga, Rodolpho C.; Thornton, Thomas; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H.; Tropsha, Alexander

2016-01-01

Skin sensitization is a major environmental and occupational health hazard. Although many chemicals have been evaluated in humans, there have been no efforts to model these data to date. We have compiled, curated, analyzed, and compared the available human and LLNA data. Using these data, we have developed reliable computational models and applied them for virtual screening of chemical libraries to identify putative skin sensitizers. The overall concordance between murine LLNA and human skin ...

Gelatin-GAG electrospun nanofibrous scaffold for skin tissue engineering: fabrication and modeling of process parameters.

Science.gov (United States)

Pezeshki-Modaress, Mohamad; Mirzadeh, Hamid; Zandi, Mojgan

2015-03-01

Electrospinning is a very useful technique for producing polymeric nanofibers by applying electrostatic forces. In this study, fabrication of novel gelatin/GAG nanofibrous mats and also the optimization of electrospinning process using response surface methodology were reported. At optimization section, gelatin/GAG blend ratio, applied voltage and feeding rate, their individual and interaction effects on the mean fiber diameter (MFD) and standard deviation of fiber diameter (SDF) were investigated. The obtained model for MFD has a quadratic relationship with gelatin/GAG blend ratio, applied voltage and feeding rate. The interactions of blend ratio and applied voltage and also applied voltage and flow rate were found significant but the interactions of blend ratio and flow rate were ignored. The optimum condition for gelatin/GAG electrospinning was also introduced using the model obtained in this study. The potential use of optimized electrospun mat in skin tissue engineering was evaluated using culturing of human dermal fibroblast cells (HDF). The SEM micrographs of HDF cells on the nanofibrous structure show that fibroblast cells can highly attach, grow and populate on the fabricated scaffold surface. The electrospun gelatin/GAG nanofibrous mats have a potential for using as scaffold for skin, cartilage and cornea tissue engineering. Copyright © 2014 Elsevier B.V. All rights reserved.

Detection of hypercholesterolemia using hyperspectral imaging of human skin

Science.gov (United States)

Milanic, Matija; Bjorgan, Asgeir; Larsson, Marcus; Strömberg, Tomas; Randeberg, Lise L.

2015-07-01

Hypercholesterolemia is characterized by high blood levels of cholesterol and is associated with increased risk of atherosclerosis and cardiovascular disease. Xanthelasma is a subcutaneous lesion appearing in the skin around the eyes. Xanthelasma is related to hypercholesterolemia. Identifying micro-xanthelasma can thereforeprovide a mean for early detection of hypercholesterolemia and prevent onset and progress of disease. The goal of this study was to investigate spectral and spatial characteristics of hypercholesterolemia in facial skin. Optical techniques like hyperspectral imaging (HSI) might be a suitable tool for such characterization as it simultaneously provides high resolution spatial and spectral information. In this study a 3D Monte Carlo model of lipid inclusions in human skin was developed to create hyperspectral images in the spectral range 400-1090 nm. Four lesions with diameters 0.12-1.0 mm were simulated for three different skin types. The simulations were analyzed using three algorithms: the Tissue Indices (TI), the two layer Diffusion Approximation (DA), and the Minimum Noise Fraction transform (MNF). The simulated lesions were detected by all methods, but the best performance was obtained by the MNF algorithm. The results were verified using data from 11 volunteers with known cholesterol levels. The face of the volunteers was imaged by a LCTF system (400- 720 nm), and the images were analyzed using the previously mentioned algorithms. The identified features were then compared to the known cholesterol levels of the subjects. Significant correlation was obtained for the MNF algorithm only. This study demonstrates that HSI can be a promising, rapid modality for detection of hypercholesterolemia.

Occurrence of human bocaviruses and parvovirus 4 in solid tissues.

Science.gov (United States)

Norja, Päivi; Hedman, Lea; Kantola, Kalle; Kemppainen, Kaisa; Suvilehto, Jari; Pitkäranta, Anne; Aaltonen, Leena-Maija; Seppänen, Mikko; Hedman, Klaus; Söderlund-Venermo, Maria

2012-08-01

Human bocaviruses 1-4 (HBoV1-4) and parvovirus 4 (PARV4) are recently discovered human parvoviruses. HBoV1 is associated with respiratory infections of young children, while HBoV2-4 are enteric viruses. The clinical manifestations of PARV4 remain unknown. The objective of this study was to determine whether the DNAs of HBoV1-4 and PARV4 persist in human tissues long after primary infection. Biopsies of tonsillar tissue, skin, and synovia were examined for HBoV1-4 DNA and PARV4 DNA by PCR. Serum samples from the tissue donors were assayed for HBoV1 and PARV4 IgG and IgM antibodies. To obtain species-specific seroprevalences for HBoV1 and for HBoV2/3 combined, the sera were analyzed after virus-like particle (VLP) competition. While HBoV1 DNA was detected exclusively in the tonsillar tissues of 16/438 individuals (3.7%), all of them ≤8 years of age. HBoV2-4 and PARV4 DNAs were absent from all tissue types. HBoV1 IgG seroprevalence was 94.9%. No subject had HBoV1 or PARV4 IgM, nor did they have PARV4 IgG. The results indicate that HBoV1 DNA occurred in a small proportion of tonsils of young children after recent primary HBoV1 infection, but did not persist long in the other tissue types studied, unlike parvovirus B19 DNA. The results obtained by the PARV4 assays are in line with previous results on PARV4 epidemiology. Copyright © 2012 Wiley Periodicals, Inc.

EPR detection of free radicals in UV-irradiated skin: mouse versus human

International Nuclear Information System (INIS)

Jurkiewicz, B.A.; Buettner, G.R.

1996-01-01

Ultraviolet radiation produces free radicals in Skh-1 mouse skin, contributing to photoaging and carcinogenesis. If a mouse model is a general indicator of free radical processes in human skin photobiology, then radical production observed in mouse and human skin should be directly comparative. In this work we show that UV radiation (λ > 300 nm, 14 μW/cm 2 UVB; 3.5 mW/cm 2 UVA) increases the ascorbate free radical (Asc) electron paramagnetic resonance (EPR) signal in both Skh-1 mouse skin (45%) and human facial skin biopsies (340%). Visible light (λ > 400 nm; 0.23 mW/cm 2 UVA) also increased the Ascsignal in human skin samples (45%) but did not increase baseline mouse Asc, indicating that human skin is more susceptible to free radical formation and that a chromophore for visible light may be present. Using EPR spin-trapping techniques, UV radiation produced spin adducts consistent with trapping lipid alkyl radicals in mouse skin (α-[4-pyridyl 1-oxide]-N-tert-butyl nitrone/alkyl radical adduct; a N = 15.56 G and a H 2.70 G) and lipid alkoxyl radicals in human skin (5,5-dimethylpyrroline -1-oxide/alkoxyl radical adduct; a N = 14.54 G and a H = 16.0 G). Topical application of the iron chelator Desferal to human skin significantly decreases these radicals (∼50%), indicating a role for iron in lipid peroxidation. (Author)

Identification of a novel proinflammatory human skin-homing Vγ9Vδ2 T cell subset with a potential role in psoriasis.

Science.gov (United States)

Laggner, Ute; Di Meglio, Paola; Perera, Gayathri K; Hundhausen, Christian; Lacy, Katie E; Ali, Niwa; Smith, Catherine H; Hayday, Adrian C; Nickoloff, Brian J; Nestle, Frank O

2011-09-01

γδ T cells mediate rapid tissue responses in murine skin and participate in cutaneous immune regulation including protection against cancer. The role of human γδ cells in cutaneous homeostasis and pathology is characterized poorly. In this study, we show in vivo evidence that human blood contains a distinct subset of proinflammatory cutaneous lymphocyte Ag and CCR6-positive Vγ9Vδ2 T cells, which is rapidly recruited into perturbed human skin. Vγ9Vδ2 T cells produced an array of proinflammatory mediators including IL-17A and activated keratinocytes in a TNF-α- and IFN-γ-dependent manner. Examination of the common inflammatory skin disease psoriasis revealed a striking reduction of circulating Vγ9Vδ2 T cells in psoriasis patients compared with healthy controls and atopic dermatitis patients. Decreased numbers of circulating Vγ9Vδ2 T cells normalized after successful treatment with psoriasis-targeted therapy. Taken together with the increased presence of Vγ9Vδ2 T cells in psoriatic skin, these data indicate redistribution of Vγ9Vδ2 T cells from the blood to the skin compartment in psoriasis. In summary, we report a novel human proinflammatory γδ T cell involved in skin immune surveillance with immediate response characteristics and with potential clinical relevance in inflammatory skin disease.

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV☆

Science.gov (United States)

Tao, Shasha; Justiniano, Rebecca; Zhang, Donna D.; Wondrak, Georg T.

2013-01-01

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I), dihydrotanshinone (DHT), tanshinone IIA (T-II-A) and cryptotanshinone (CT)] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1) with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm2 UVB; 1.53 J/cm2 UVA). The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities) was significantly attenuated in DHT

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV.

Science.gov (United States)

Tao, Shasha; Justiniano, Rebecca; Zhang, Donna D; Wondrak, Georg T

2013-01-01

Exposure to solar ultraviolet (UV) radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2), a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I), dihydrotanshinone (DHT), tanshinone IIA (T-II-A) and cryptotanshinone (CT)] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1) with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm(2) UVB; 1.53 J/cm(2) UVA). The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities) was significantly attenuated in DHT

The Nrf2-inducers tanshinone I and dihydrotanshinone protect human skin cells and reconstructed human skin against solar simulated UV

Directory of Open Access Journals (Sweden)

Shasha Tao

2013-01-01

Full Text Available Exposure to solar ultraviolet (UV radiation is a causative factor in skin photocarcinogenesis and photoaging, and an urgent need exists for improved strategies for skin photoprotection. The redox-sensitive transcription factor Nrf2 (nuclear factor-E2-related factor 2, a master regulator of the cellular antioxidant defense against environmental electrophilic insult, has recently emerged as an important determinant of cutaneous damage from solar UV, and the concept of pharmacological activation of Nrf2 has attracted considerable attention as a novel approach to skin photoprotection. In this study, we examined feasibility of using tanshinones, a novel class of phenanthrenequinone-based cytoprotective Nrf2 inducers derived from the medicinal plant Salvia miltiorrhiza, for protection of cultured human skin cells and reconstructed human skin against solar simulated UV. Using a dual luciferase reporter assay in human Hs27 dermal fibroblasts pronounced transcriptional activation of Nrf2 by four major tanshinones [tanshinone I (T-I, dihydrotanshinone (DHT, tanshinone IIA (T-II-A and cryptotanshinone (CT] was detected. In fibroblasts, the more potent tanshinones T-I and DHT caused a significant increase in Nrf2 protein half-life via blockage of ubiquitination, ultimately resulting in upregulated expression of cytoprotective Nrf2 target genes (GCLC, NQO1 with the elevation of cellular glutathione levels. Similar tanshinone-induced changes were also observed in HaCaT keratinocytes. T-I and DHT pretreatment caused significant suppression of skin cell death induced by solar simulated UV and riboflavin-sensitized UVA. Moreover, feasibility of tanshinone-based cutaneous photoprotection was tested employing a human skin reconstruct exposed to solar simulated UV (80 mJ/cm2 UVB; 1.53 J/cm2 UVA. The occurrence of markers of epidermal solar insult (cleaved procaspase 3, pycnotic nuclei, eosinophilic cytoplasm, acellular cavities was significantly attenuated in DHT

QSAR models of human data can enrich or replace LLNA testing for human skin sensitization

Science.gov (United States)

Alves, Vinicius M.; Capuzzi, Stephen J.; Muratov, Eugene; Braga, Rodolpho C.; Thornton, Thomas; Fourches, Denis; Strickland, Judy; Kleinstreuer, Nicole; Andrade, Carolina H.; Tropsha, Alexander

2016-01-01

Skin sensitization is a major environmental and occupational health hazard. Although many chemicals have been evaluated in humans, there have been no efforts to model these data to date. We have compiled, curated, analyzed, and compared the available human and LLNA data. Using these data, we have developed reliable computational models and applied them for virtual screening of chemical libraries to identify putative skin sensitizers. The overall concordance between murine LLNA and human skin sensitization responses for a set of 135 unique chemicals was low (R = 28-43%), although several chemical classes had high concordance. We have succeeded to develop predictive QSAR models of all available human data with the external correct classification rate of 71%. A consensus model integrating concordant QSAR predictions and LLNA results afforded a higher CCR of 82% but at the expense of the reduced external dataset coverage (52%). We used the developed QSAR models for virtual screening of CosIng database and identified 1061 putative skin sensitizers; for seventeen of these compounds, we found published evidence of their skin sensitization effects. Models reported herein provide more accurate alternative to LLNA testing for human skin sensitization assessment across diverse chemical data. In addition, they can also be used to guide the structural optimization of toxic compounds to reduce their skin sensitization potential. PMID:28630595

Spectral Detection of Human Skin in VIS-SWIR Hyperspectral Imagery without Radiometric Calibration

Science.gov (United States)

2012-03-01

6 Spectral reflectance of human skin at VIS-SWIR wavelengths. Skin with less melanin appears brighter because it has higher reflectance...6 illustrates the spectral reflectance of human skin with different melanin levels. One paper proposes a Normalized Difference Skin Index (NDSI), a...1.4% Melanin 12.6% Melanin 23.2% Melanin 34.3% Melanin 45% Melanin Figure 6. Spectral reflectance of human skin at VIS-SWIR wavelengths. Skin with less

Characterization of ERAS, a putative novel human oncogene, in skin and breast

Energy Technology Data Exchange (ETDEWEB)

Peña Avalos, B.L. de la

2014-07-01

Most human tumors have mutations in genes of the RAS small GTPase protein family. RAS works as a molecular switch for signaling pathways that modulate many aspects of cell behavior, including proliferation, differentiation, motility and death. Oncogenic mutations in RAS prevent GTP hydrolysis, locking RAS in a permanently active state, being the most common mutations in HRAS, KRAS and NRAS. The human RAS family consists of at least 36 different genes, many of which have been scarcely studied. One of these relatively unknown genes is ERAS (ES cell-expressed RAS), which is a constitutively active RAS protein, localized in chromosome X and expressed only in embryonic cells, being undetectable in adult tissues. New high throughput technologies have made it possible to screen complete cancer genomes for identification of mutations associated to cancer. Using the Sleeping Beauty (SB) transposon system, ERAS was identified as a putative novel oncogene in non-melanoma skin and breast cancers. The major aim of this project is to determine the general characteristics of ERAS as a putative novel human oncogene in skin and breast cells. Forced expression of ERAS results in drastic changes in cell shape, proliferation and motility. When ERAS is overexpressed in skin and breast human cells it is mainly localized in the cytoplasmic membrane. ERAS activates the phosphatidylinositol-3-OH kinase (PI3K) pathway but not the mitogen-activated protein kinase (MAPK) pathway. ERAS-expressing cells suffer spontaneous morphologic and phenotypic EMT-like changes, including cytoskeleton reorganization, vimentin and N-cadherin up-regulation and down-regulation of E-cadherin, which can be associated with increased malignancy, and invasive and metastatic potential. Our results suggest that inappropriate expression of ERAS lead to transformation of human cells. (Author)

Vital roles of stem cells and biomaterials in skin tissueengineering

Institute of Scientific and Technical Information of China (English)

Abu Bakar Mohd Hilmi; Ahmad Sukari Halim

2015-01-01

Tissue engineering essentially refers to technologyfor growing new human tissue and is distinct fromregenerative medicine. Currently, pieces of skin arealready being fabricated for clinical use and manyother tissue types may be fabricated in the future.Tissue engineering was first defined in 1987 by theUnited States National Science Foundation whichcritically discussed the future targets of bioengineeringresearch and its consequences. The principles oftissue engineering are to initiate cell cultures in vitro ,grow them on scaffolds in situ and transplant thecomposite into a recipient in vivo . From the beginning,scaffolds have been necessary in tissue engineeringapplications. Regardless, the latest technology hasredirected established approaches by omitting scaffolds.Currently, scientists from diverse research institutesare engineering skin without scaffolds. Due to theiradvantageous properties, stem cells have robustlytransformed the tissue engineering field as part of anengineered bilayered skin substitute that will later bediscussed in detail. Additionally, utilizing biomaterialsor skin replacement products in skin tissue engineeringas strategy to successfully direct cell proliferation anddifferentiation as well as to optimize the safety ofhandling during grafting is beneficial. This approachhas also led to the cells＇ application in developing thenovel skin substitute that will be briefly explained in thisreview.

Black Tattoos Entail Substantial Uptake of Genotoxicpolycyclic Aromatic Hydrocarbons (PAH) in Human Skin and Regional Lymph Nodes

Science.gov (United States)

Lehner, Karin; Santarelli, Francesco; Vasold, Rudolf; Penning, Randolph; Sidoroff, Alexis; König, Burkhard; Landthaler, Michael; Bäumler, Wolfgang

2014-01-01

Hundreds of millions of people worldwide have tattoos, which predominantly contain black inks consisting of soot products like Carbon Black or polycyclic aromatic hydrocarbons (PAH). We recently found up to 200 μg/g of PAH in commercial black inks. After skin tattooing, a substantial part of the ink and PAH should be transported to other anatomical sites like the regional lymph nodes. To allow a first estimation of health risk, we aimed to extract and quantify the amount of PAH in black tattooed skin and the regional lymph nodes of pre-existing tattoos. Firstly, we established an extraction method by using HPLC – DAD technology that enables the quantification of PAH concentrations in human tissue. After that, 16 specimens of human tattooed skin and corresponding regional lymph nodes were included in the study. All skin specimen and lymph nodes appeared deep black. The specimens were digested and tested for 20 different PAH at the same time.PAH were found in twelve of the 16 tattooed skin specimens and in eleven regional lymph nodes. The PAH concentration ranged from 0.1–0.6 μg/cm2 in the tattooed skin and 0.1–11.8 μg/g in the lymph nodes. Two major conclusions can be drawn from the present results. Firstly, PAH in black inks stay partially in skin or can be found in the regional lymph nodes. Secondly, the major part of tattooed PAH had disappeared from skin or might be found in other organs than skin and lymph nodes. Thus, beside inhalation and ingestion, tattooing has proven to be an additional, direct and effective route of PAH uptake into the human body. PMID:24670978

[Physiological features of skin ageing in human].

Science.gov (United States)

Tikhonova, I V; Tankanag, A V; Chemeris, N K

2013-01-01

The issue deals with the actual problem of gerontology, notably physiological features of human skin ageing. In the present review the authors have considered the kinds of ageing, central factors, affected on the ageing process (ultraviolet radiation and oxidation stress), as well as the research guidelines of the ageing changes in the skin structure and fuctions: study of mechanical properties, microcirculation, pH and skin thickness. The special attention has been payed to the methods of assessment of skin blood flow, and to results of investigations of age features of peripheral microhemodynamics. The laser Doppler flowmetry technique - one of the modern, noninvasive and extensively used methods for the assessmant of skin blood flow microcirculation system has been expanded in the review. The main results of the study of the ageing changes of skin blood perfusion using this method has been also presented.

Chronic effects of UV on human skin

International Nuclear Information System (INIS)

Cesarini, J.P.

1996-01-01

Chronic exposures and acute accidents of the skin to UV has been recognized as an important risk for skin cancers in human. Attempts have been made with mathematical models to correlate the ambient UV dose and occupational irradiations with the risk of skin cancers. Development of accurate global measurements of solar irradiance and personal dosimetry is expected in the future in order to reduce the exposure of the general population, to precise the measures to be taken for indoor and outdoor workers. (author)

[New views about the skin].

Science.gov (United States)

Guimberteau, J-C; Delage, J-P; Wong, J

2010-08-01

As the follow up article to "Introduction to the knowledge of subcutaneous sliding system in humans" published in the "Annales de chirurgie plastique" we further investigate the architecture of the skin and comment on the subcutaneous multifibrillar and microvacuolar arrangements that provide form, mobility, adaptability and resistance to force of gravity. The study aimed to highlight the direct link between the skin and subcutaneous environment in dynamic living tissue. Through high resolution endoscopic observations made during live surgery it is revealed how microvacuoles and microspaces can provide dynamic structure and form during movement between the epidermis, dermis and hypodermis. The study reveals intriguing morphodynamics which are necessary to maintain mobility and continuity to neighboring tissues. The polyhedric design of the skin surface directly relates to multifibrillar pillars beneath the skin which dictate their patterning and movement. The concept of tissue continuity is realised by the chaotic and fractal organisation of multifibrils interlaced with cellular components which characteristics alter depending on the state of hydration. Understanding the integral arrangement that provides continuity of all the structures below the skin provides an appreciation to how skin behaves in relation to movement of the rest of the body. 2009. Published by Elsevier SAS.

Prediction of Human Pharmacokinetic Profile After Transdermal Drug Application Using Excised Human Skin.

Science.gov (United States)

Yamamoto, Syunsuke; Karashima, Masatoshi; Arai, Yuta; Tohyama, Kimio; Amano, Nobuyuki

2017-09-01

Although several mathematical models have been reported for the estimation of human plasma concentration profiles of drug substances after dermal application, the successful cases that can predict human pharmacokinetic profiles are limited. Therefore, the aim of this study is to investigate the prediction of human plasma concentrations after dermal application using in vitro permeation parameters obtained from excised human skin. The in vitro skin permeability of 7 marketed drug products was evaluated. The plasma concentration-time profiles of the drug substances in humans after their dermal application were simulated using compartment models and the clinical pharmacokinetic parameters. The transdermal process was simulated using the in vitro skin permeation rate and lag time assuming a zero-order absorption. These simulated plasma concentration profiles were compared with the clinical data. The result revealed that the steady-state plasma concentration of diclofenac and the maximum concentrations of nicotine, bisoprolol, rivastigmine, and lidocaine after topical application were within 2-fold of the clinical data. Furthermore, the simulated concentration profiles of bisoprolol, nicotine, and rivastigmine reproduced the decrease in absorption due to drug depletion from the formulation. In conclusion, this simple compartment model using in vitro human skin permeation parameters as zero-order absorption predicted the human plasma concentrations accurately. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Reconstructing in-vivo reflectance spectrum of pigmented skin lesion by Monte Carlo simulation

Science.gov (United States)

Wang, Shuang; He, Qingli; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

2012-03-01

In dermatology applications, diffuse reflectance spectroscopy has been extensively investigated as a promising tool for the noninvasive method to distinguish melanoma from benign pigmented skin lesion (nevus), which is concentrated with the skin chromophores like melanin and hemoglobin. We carried out a theoretical study to examine melanin distribution in human skin tissue and establish a practical optical model for further pigmented skin investigation. The theoretical simulation was using junctional nevus as an example. A multiple layer skin optical model was developed on established anatomy structures of skin, the published optical parameters of different skin layers, blood and melanin. Monte Carlo simulation was used to model the interaction between excitation light and skin tissue and rebuild the diffuse reflectance process from skin tissue. A testified methodology was adopted to determine melanin contents in human skin based on in vivo diffuse reflectance spectra. The rebuild diffuse reflectance spectra were investigated by adding melanin into different layers of the theoretical model. One of in vivo reflectance spectra from Junctional nevi and their surrounding normal skin was studied by compare the ratio between nevus and normal skin tissue in both the experimental and simulated diffuse reflectance spectra. The simulation result showed a good agreement with our clinical measurements, which indicated that our research method, including the spectral ratio method, skin optical model and modifying the melanin content in the model, could be applied in further theoretical simulation of pigmented skin lesions.