Laminar Biomaterial Composite of PVA Cryogel with Amnion as Potential Wound Dressing.

Gel dressings, composed of polymers both natural and synthetic, are successfully used in the treatment of burn wounds. They protect the burn wound site against adverse external factors, ensure an adequate level of tissue hydration, have soothing and pain-relieving properties, and also support the healing process and reduce the risk of pathological scars. Another promising material that can be used in the wound-healing process is an amnion membrane. Due to its valuable properties such as protecting the body against bacterial infections and permeability to nutrition, it has found usage in different brands of medicine. In this work, we have combined the beneficial properties of hydrogels and amnion in order to make the laminar dressing that may serve for wound healing. For that purpose, the physically crosslinked cryogel of poly(vinyl alcohol) (PVA) was covered with an amnion membrane. Subsequently, gamma irradiation was performed, leading to the simultaneous internal crosslinking of the hydrogel, its permanent bonding with the amnion, and dressing sterilization. The physicochemical properties of the dressing including gel fraction, swelling, and hardness were studied. Biological tests such as the MTT assay, antimicrobial activity, and histopathological examination confirmed that the obtained material constituted a promising candidate for further, more in-depth studies aiming at wound dressing application.

Platelet-Rich Plasma and Acellular Dermal Matrix in the Surgical Treatment of Hidradenitis Suppurativa: A Comparative Retrospective Study.

(1) Introduction: Hidradenitis suppurativa (HS) is an inflammatory skin disease with recurrent, chronic, painful, and purulent skin lesions. Topical or systemic antibiotics are the most widely used treatments for the management of mild stages of the disease. In chronic cases (Hurley II/III), wide excision of lesions should be considered. During reconstructive surgery, the most problematic aspect is wound closure. Very large excisional wounds require reconstructive techniques such as skin flaps, skin grafts, or both. Surgical methods have their limitations, so reconstructive methods in HS surgery need to be continuously improved through the use of, for example, platelet-rich plasma and acellular dermal matrix; (2) Methods: The aim of this study was to evaluate the clinical outcomes and efficacy of surgical treatment of patients with HS using local skin flaps injected with PRP compared to a group of local skin flaps without platelet-rich plasma injection, an acellular dermal matrix, and split-thickness skin graft co-grafts. Sixty-one patients (29 males and 32 females) were included in the study. Most patients were characterized by Hurley grade III HS; (3) Results: The use of PRP injection in reconstructions (skin flaps) improved healing and reduced the number of complications, a notable trend in this study. A co-graft of acellular dermal matrix and split-thickness skin graft gave better therapeutic results than split-thickness skin graft alone (fewer days in hospital, fewer postoperative complications); (4) Conclusions: PRP injected into skin flaps, co-grafted acellular dermal matrix, and split-thickness skin grafts are good options for the surgical treatment of hidradenitis suppurativa.

The urgent need to achieve an optimal strategic stock of human allogeneic skin graft materials in case of a mass disaster in Poland.

A burn is a sudden injury which immediate or long-term consequences may be life-threatening for the patient. A mass disaster event may involve large numbers of severely burned patients. Patients of this type typically have a limited area of healthy, unburned skin from which an autologous split thickness skin graft could be collected. In a clinical situation of this type, it is necessary to use a particular skin substitute. Non-viable allogeneic human skin graft materials might be considered as the most suitable skin substitutes in the treatment of such patients. At present, Poland does not have a sufficient supply of human allogeneic skin graft materials to meet the needs arising from a sudden and unforeseen mass disaster. This study involved an analysis of selected mass disasters. From this an estimate was made from a verified casualty profile of the necessary minimum stock of human allogeneic skin graft materials. An insufficient amount of skin results from an inadequate number of skin donors, which in turn results from the current tissue donation system. Therefore, a proposal has been made for the organizational, legal and systemic changes required to improve the situation in Polish transplantology, with particular emphasis on skin donation. In order to achieve a strategic stock of human skin grafts, a tissue collecting transplantation team should be organized. The rights and obligations of the non-physician transplant team member should be extended. Proposals have been made for awareness campaigns (adverts, posters etc.) and educational schemes (educational video, lectures during transplant coordinator training, etc.). Finally, a proposal has been made for possible methods to deal with the logistic management of the allogeneic skin stock. The required, essential stock of human allogeneic skin in the event of a mass disaster has been estimated at 600,000 cm2.

Influence of electron beam irradiation on extracellular matrix of the human allogeneic skin grafts.

The nonviable allogeneic human skin grafts might be considered as the most suitable skin substitutes in the treatment of extensive and deep burns. However, in accordance to biological security such grafts require the final sterilization prior to clinical application. The aim of the study was to verify the influence of electron beam irradiation of three selected doses: 18, 25, and 35 kGy on the extracellular matrix of human skin. Prior to sterilization, the microbiological tests were conducted and revealed contamination in all examined cases. Individual groups were subjected to single electron beam radiation sterilization at proposed doses and then subjected to microbiological tests again. The results of microbiological testing performed for all irradiation doses used were negative. Only in the control group was a growth of microorganisms observed. The FTIR spectrometry tests were conducted followed by the histological evaluation and mechanical tests. In addition, cost analysis of radiation sterilization of individual doses was performed. The results of spectroscopic analysis, mechanical tests, and histological staining showed no significant changes in composition and characteristics of tested tissues after their irradiation, in comparison to control samples. The cost analysis has shown that irradiation with 18 kGy is the most cost-effective and 35 kGy is the least favorable. However, according to biological risk reduction, the recommended sterilization dose is 35 kGy, despite the higher price compared to the other doses tested.

Tissue Engineering in Skin Substitute.

Thermal injuries may cause significant damage to large areas of the skin. Extensive and deep burn wounds require specialized therapy. The optimal method in the strategy of treating extensive, full thickness burns (III°) is the use of autologous split thickness skin grafts STSG (Busuioc et al. Rom J Morphol Embryol 4:1061-1067, 2012; Kitala D, Kawecki M, Klama-Baryla A, Labus W, Kraut M, Glik J, Ryszkiel I, Kawecki MP, Nowak M. Allogeneic vs. Autologous Skin Grafts in the Therapy of Patients with Burn Injuries: A Restrospective, Open-label Clinical Study with Pair Matching. Adv Clin Exp Med. 2016 Sep-Oct;25(5):923-929.; Glik J, Kawecki M, Kitala D, Klama-Baryla A, Labus W, Grabowski M, Durdzinska A, Nowak M, Misiuga M, Kasperczyk A. A new option for definitive burn wound closure - pair matching type of retrospective case-control study of hand burns in the hospitalized patients group in the Dr Stanislaw Sakiel Center for Burn Treatment between 2009 and 2015. Int Wound J. 2017 Feb 21. https://doi.org/10.1111/iwj.12720 . [Epub ahead of print]; Prim et al. May 24Wound Repair Regen., 2017; Grossova et al. Mar 31Ann Burns Fire Disasters 30:5-8, 2017). The main limitation of that method is the inadequate amount of healthy, undamaged skin (donor sites), which could be harvested and used as a graft. Moreover, donor sites are an additional wounds that require analgesic therapy, leave scars during the healing process and they are highly susceptible to infection (1-6). It must be emphasized that in terms of the treatment of severe, deep and extensive burns, and there should be no doubt that the search for a biocompatible skin substitute that would be able to replace autologous STSG is an absolute priority. The above-mentioned necessitates the search for new treatment methods of severe burn wounds. Such methods could consider the preparation and application of bioengineered, natural skin substitutes. At present, as the clinical standard considered by the physicians may be use of available biological skin substitutes, e.g., human allogeneic skin, in vitro cultured skin cells, acellular dermal matrix ADM and revitalized ADMs, etc. (Busuioc et al. Rom J Morphol Embryol 4:1061-1067, 2012; Kitala D, Kawecki M, Klama-Baryla A, Labus W, Kraut M, Glik J, Ryszkiel I, Kawecki MP, Nowak M. Allogeneic vs. Autologous Skin Grafts in the Therapy of Patients with Burn Injuries: A Restrospective, Open-label Clinical Study with Pair Matching. Adv Clin Exp Med. 2016 Sep-Oct;25(5):923-929.; Glik J, Kawecki M, Kitala D, Klama-Baryla A, Labus W, Grabowski M, Durdzinska A, Nowak M, Misiuga M, Kasperczyk A. A new option for definitive burn wound closure - pair matching type of retrospective case-control study of hand burns in the hospitalised patients group in the Dr Stanislaw Sakiel Center for Burn Treatment between 2009 and 2015. Int Wound J. 2017 Feb 21. https://doi.org/10.1111/iwj.12720 . [Epub ahead of print]; Prim et al. May 24Wound Repair Regen., 2017; Grossova et al. Mar 31Ann Burns Fire Disasters 30:5-8, 2017; Labus et al. FebJ Biomed Mater Res B Appl Biomater 106:726-733, 2018).

Alternative to Poly(2-isopropyl-2-oxazoline) with a Reduced Ability to Crystallize and Physiological LCST.

In this work, we sought to examine whether the presence of alkyl substituents randomly distributed within the main chain of a 2-isopropyl-2-oxazoline-based copolymer will decrease its ability to crystallize when compared to its homopolymer. At the same time, we aimed to ensure an appropriate hydrophilic/lipophilic balance in the copolymer and maintain the phase transition in the vicinity of the human body temperature. For this reason, copolymers of 2-ethyl-4-methyl-2-oxazoline and 2-isopropyl-2-oxazoline were synthesized. The thermoresponsive behavior of the copolymers in water, the influence of salt on the cloud point, the presence of hysteresis of the phase transition and the crystallization ability in a water solution under long-term heating conditions were studied by turbidimetry. The ability of the copolymers to crystallize in the solid state, and their thermal properties, were analyzed by differential scanning calorimetry and X-ray diffractometry. A cytotoxicity assay was used to estimate the viability of human fibroblasts in the presence of the obtained polymers. The results allowed us to demonstrate a nontoxic alternative to poly(2-isopropyl-2-oxazoline) (PiPrOx) with a physiological phase transition temperature (LCST) and a greatly reduced tendency to crystallize. The synthesis of 2-oxazoline polymers with such well-defined properties is important for future biomedical applications.

The use of biostatic human amnion and platelet-rich plasma in topical treatment of toxic epidermal necrolysis-A case report.

BACKGROUND: Toxic epidermal necrolysis (TEN) (also known as Lyell syndrome) and Stevens-Johnson syndrome (SJS) are life-threatening mucocutaneous blistering diseases. They are characterized by generalized blisters and epidermal inflammation, most likely resulting from the administration or interaction of medicines. AIMS: To report potential new method in the treatment of TEN. PATIENTS/METHODS: This article presents a case report of a 35-year-old man suffering from TEN covering about 95% of his body surface. Lesions occurred in the patient during antiepileptic therapy, after taking simultaneously amoxicillin (with clavulanic acid) and naproxen followed by lamotrigine treatment. Standard general treatment was performed. Intravenous feeding was necessary. Due to acute respiratory failure, the patient required mechanical ventilation. Two methods were combined in topical treatment: application of platelet-rich plasma (PRP) and a simultaneous biostatic human amnion transplant. RESULTS: In the presented case, the combination of both methods contributed to a significant acceleration of wound healing. After the application of PRP and biostatic amnion transplantation, the healing of wounds on the back and posterior surfaces of the legs was completed after six days. The surgical treatment most probably contributed to a significant acceleration of wound healing. CONCLUSION: The case report shows that topical TEN/SJS treatment with biostatic human amnion and PRP has a positive clinical effect and may be a new method of treatment of TEN.

Historical and modern research on propolis and its application in wound healing and other fields of medicine and contributions by Polish studies.

ETHNOPHARMACOLOGICAL RELEVANCE: The history of medical application of propolis (also known as bee glue) dates back to the times of ancient Greeks, Romans, Persians and Egyptians. Honey and other bee products, including propolis, occupy an important place in Polish folk medicine. Scientific research on propolis in Poland began in the early 1960s in Zabrze and continues until now. AIM OF THE REVIEW: The aim of this review is to provide an overview of information on Polish research on propolis and its medical application with particular emphasis on studies concerning wound healing. Consequently, our goal is also to shed a new light on therapeutic potential of Polish propolis in order to support future research in the field. MATERIALS AND METHODS: A systematic review of scientific literature on propolis and its medical application was performed by using the literature databases (PubMed, Web of Science, Google Scholar). We paid special attention to papers describing the effect of propolis on skin wound healing as well as to Polish contribution to research on propolis. RESULTS: Professor Stan Scheller was the first Polish scientist dealing with propolis and its medical potential. His legacy was continued by several research teams that studied the topic in various aspects. They analyzed propolis composition, its antioxidant, anti-inflammatory, antimicrobial, antiapoptotic and anticancer properties as well as its application in dentistry and wound treatment. Burn wound healing physiology after propolis administration was thoroughly studied on pig model, whereas research on patients proved the efficacy of propolis in chronic venous leg ulcer treatment. CONCLUSION: Polish scientists have made a significant contribution to the research on propolis, its biological properties and influence on wound healing. Propolis ointments can effectively accelerate the healing process and improve healing physiology, so they can be recommended as a promising topical medication for wound treatment in the future clinical and preclinical trials.

Porcine Transgenic, Acellular Material as an Alternative for Human Skin.

Although new therapeutic approaches for burn treatment have made progress, there is still need for efficient coverage of donor fields. Promising dressing for skin graft donor site should be biocompatible, attach easily to the wound bed, remain in place until donor site has renewed, and decrease morbidity at the site. Porcine skin may be applied as a dressing for severe burns. Therefore pig skin xenografts can be used also as donor field coverage. In the Burn Treatment Centre, we used gauze soaked in Vaseline to secure donor fields. The aim of the study was to check if transgenic porcine skin is better than standard in donor site coverage used in our center. We showed that dressing reduces pain experienced by patients. The dressing leads to a reduction of hospitalization time by an average of 8 days. The dressing is as safe as the gold standard. Securing the donor field reduces the risk of colonization of the wound in the second smear after application by 60%. The disadvantage of the dressing is the inability to absorb blood; the use of hemostatic ointments in combination with the skin of transgenic pigs should be considered in the future.

Amniotic Stem Cells Cultured on Thermoresponsive Polymers Allow Obtaining a Full Cell Sheet.

Amniotic stem cells promote adhesion and migration of epithelial cells. Obtaining a full sheet containing amniotic stem cells seems to be the best solution for the treatment of burn wounds. The main advantage of this method is obtaining a full sheet of cells by lowering the temperature below the transition temperature, which does not affect extracellular matrix. The purpose of this work was to produce a skin substitute-a full sheet consisting of amniotic mesenchymal stem cells-and compare with well-known fibroblast sheet. Amniotic membrane cells revealed better tendency to full sheet detachment than fibroblasts. Confluence after 24 hours was always higher on polymer-coated dishes than on normal polypropylene dishes. Also viability was higher than on the control culture dish, while the number of apoptotic cells was always highest on polypropylene (control). Ile-Lys-Val-ala-Val (IKVAV) 0.28 addition to poly (poly [ethylene glycol] ethyl methacrylate) (PTEGMA) caused best cell confluence and highest percentage of cells in mitosis phase of cell cycle, but also worst cell detachment was observed in both cell types on PTEGMA IKVAV 0.28. Viability of cells transferred in cell sheet form onto a new culture dish was higher than when detached as suspension enzymatically. Additionally, percentage of apoptotic cells transferred in cell sheet form onto a new culture dish was always lower than when detached as suspension enzymatically. Culturing of PTEGMA, PTEGMA IKVAV 0.28 and PTEGMA IKVAV 0.14 have a stimulating effect on number of cells in mitosis in amniotic cell culture even after cell sheet transfer onto a new dish, whereas such effect with fibroblast was not observed.

The Causes for the Loss of Cellular Material at the Qualification Stage and the Influence of the Patient's Flora on Culture Infection.

There are several causes leading to the loss of cellular material earmarked for transplantation. This paper aims to evaluate the number of lost donors and lost cells in the culture by means of verifying both the results of the qualification tests and the presence of microorganisms in the cellular material. The analysis involved 86 donors hospitalized for thermal burns, from whom cells were harvested for keratinocyte and fibroblast cultures in the years 2011 to 2015. All potential donors underwent qualification tests: Anti-HIV-1,2; HBsAg; Anti-HCV-Ab; HBc, and a specific test for syphilis. In the case of skin fragments collected for culturing, the microbiological tests included the carrying fluid, the medium after 1 change, and the medium during culturing and before transplantation. Skin donors for cell cultures were assigned to the groups based on if the skin was collected up to 7 days following the burn or later. On average, 12% of the disqualifications were reported among donors for cell culturing. The most frequent cause of donor disqualification (54% of all disqualifications) was a positive HBc(+). The occurrence of fungal infections detected in the cellular material was over 30%. Establishing the culture after day 7 following the injury immediately increases the risk of infection by 25% in comparison to those cultures established before or on day 7 following the injury. Proper disinfection of donor place is crucial, but sometimes insufficient for maintenance sterility in cell culture. The risk of infection increases 25% after 7 following the injury.

Amniotic and Umbilical Cord of Transgenic Pigs as an Alternative Source of Stem Cells.

BACKGROUND: The placenta is worthy of consideration as a source of tissues for transplantation. Porcine material preparation allows significantly more grafts to be obtained than human material. Amniotic cells are a very practicable stem cell type and easy to obtain with great potential, compared with, for instance, adipose-derived stem cells. The aim of this paper was to verify if porcine transgenic amnion and umbilical cord could be as effective for xenotransplantation of stem cells as human material. METHODS: Oxytocin was administered to the sows on the day the material was obtained. The obtained material was divided by weight into 4 relatively equal parts, which were transferred into 1 of 4 containers. The containers had different transport media and a concentration of antibiotics. After cell isolation by homogenization, the number of live, dead, and apoptotic cells was assessed. RESULTS: Maintaining the sterility when obtaining material from breeding pigs was the biggest problem. Transport medium, despite the addition of antibiotics, was in most cases infected. Tests revealed that porcine cells have a tendency to leave tissue material and adhere to plastic as human cells do. Porcine cells are also fibroblast like, which can suggest that these cells might be tested for the presence of mesenchymal stem cells. However, some differences are visible in all parameters, which can result from contamination of material or improper transport medium. There were significant differences between viability and apoptotic cell number in human and transgenic pig cells isolated from both sources---amniotic membrane and umbilical cord.

Infrared Thermal Imaging as a Method of Improving Skin Graft Qualification Procedure and Skin Graft Survivability.

BACKGROUND: Appropriate wound classification (evaluation of skin damage depth) is a key element in the first days after the burn injury. In this study, we used a thermovision system to evaluate the degree of burn wound shortly after injury and the regenerative process of engraftment of autologous split-thickness skin grafts (STSGs). The results were referenced to wound assessment made by a physician. METHODS: Twenty-one patients with STSGs were included in the study. The analysis of the dependence between the assessment of burn depth obtained with the use of numeric models (thermovision examination) and clinical assessment by physicians was conducted. Computed tomography angiography (CTA) was performed. RESULTS: The study demonstrated that thermovision images allowed physicians a deeper assessment of burns. Decrease in the temperature difference was observed in subsequent measurements. Temperature increase during normal graft healing was observed. Graft vascularization was confirmed by CTA. CONCLUSION: Thermovision may be useful in assessment of the clinical condition of burn wounds and monitoring of wound healing progress.

Application of Amniotic Stem Cells on an Acellular Dermal Matrix Scaffold in a Burned Patient: A Case Report.

BACKGROUND: Advances in science have allowed newly created medicinal products based on gene therapy, somatic cell therapy, and tissue engineering to be used in the treatment of human diseases. December 2008 legislation aims to ensure they are both safe for patients and available throughout the European Union. Amniotic stem cells are designated by the European Medicines Agency Committee for Advanced Therapies as an advanced therapy medicinal product; therefore, production must be in accordance with Regulation (EC) No. 1394/2007 of the European Council of 13 November 2007 on advanced therapy medicinal products. OBJECTIVES: This article details preliminary results of innovative amniotic stem cell transplant (supported by an acellular dermal matrix [ADM] produced in-house with Suprathel wound and burn dressing) in a burn patient and compares them with results in a patient treated with allogeneic skin. MATERIAL AND METHODS: Amniotic stem cells were applied to a 40-year-old patient with IIb°/III° thermal burns of 36% of total body surface area and III°/IV° of 1%. Wound healing was assessed by histologic examination and the Bates-Jensen scale. Reduction in pain perception was verified by 10-point visual analog scale. Hospitalization time was compared to length of stay for patients treated with standard therapy. RESULTS: The patient was discharged from hospital on the 12th day after surgery with complete wound healing (almost 2 times shorter than the control). CONCLUSIONS: The use of amniotic stem cells and ADM may be the optimal method for burn treatment.

Is Transgenic Porcine Skin as Good as Allogeneic Skin for Regenerative Medicine? Comparison of Chosen Properties of Xeno- and Allogeneic Material.

BACKGROUND: Burn treatment is associated with the need of dressing large cutaneous defects. There is a need of alternative search for the allogeneic skin as a source of grafting for a clinical use. Such sources include animals. For many years, porcine skin was used as a biological dressing for wounds or donor's fields, or residual fields after skin grafting. Current studies aim to minimize immunogenicity, inter alia, through the decellularization process. MATERIALS AND METHODS: The decellularization methods and porcine skin resettlement of human keratinocytes and fibroblasts were evaluated. The mechanical properties of the dressings and their influence on the viability, apoptosis, population doubling, and cell cycle of keratinocytes and fibroblasts were examined. The inheritance of cell antigens responsible for histocompatibility on the human keratinocyte and fibroblast surface in the cultures incubated with examined variants of dressings from porcine skin were analyzed. RESULTS: The most effective acellularization method is trypsinization. Morphology of the cell remained proper and stable during the whole experiment. In both fibroblast and keratinocyte cultures, the highest number of apoptotic cells was observed when samples were incubated with allogeneic skin. In the keratinocyte cultures, the highest number of live cells was observed when incubated with porcine transgenic acellular dermal matrix. The acellular matrices influence the increase of population doubling of keratinocytes in the cultures. CONCLUSION: For routine acellurization, trypsinization was chosen as the most effective method with preservation of tissue properties.

Preparation of placental tissue transplants and their application in skin wound healing and chosen skin bullous diseases - Stevens-Johnson syndrome and toxic epidermal necrolysis treatment.

Unique properties of amniotic membrane make it a promising source for tissue engineering and a clinically useful alternative for patients suffering from chronic wounds including, for example, ulcers, burns, ocular surface damages and wounds occurring in the course of bullous diseases like stevens-johnson syndrome and toxic epidermal necrolysis. Its use has many advantages over standard wound care, as it contains pluripotent cells, nutrients, anti-fibrotic and anti-inflammatory cytokines, growth factors and extracellular matrix (ECM) proteins. Placental tissues can be prepared as a medical component, an advanced therapy medicinal product or a tissue graft. In addition to basic preparation procedures such as washing, rinsing, cutting, drying and sterilisation, there are many optional steps such as perforation, crosslinking and decellularisation. Finally, transplants should be properly stored-in cryopreserved or dehydrated form. In recent years, many studies including basic science and clinical trials have proven the potential to expand the use of amniotic membrane and amnion-derived cells to the fields of orthopaedics, dentistry, surgery, urology, vascular tissue engineering and even oncology. In this review, we discuss the role of placental tissues in skin wound healing and in the treatment of various diseases, with particular emphasis on bullous diseases. We also describe some patented procedures for placental tissue grafts preparation.

A new approach to the production of a biovital skin graft based on human acellular dermal matrix produced in-house, in vitro revitalized internally by human fibroblasts and keratinocytes on the surface.

Patients with extensive and deep burns who do not have enough donor sites for autologous skin grafts require alternative treatment methods. Tissue engineering is a useful tool to solve this problem. The aim of this study was to find the optimal method for the production of a biovital skin substitute based on acellular dermal matrix (ADM) and in vitro cultured fibroblasts and keratinocytes. In this work, nine methods of ADM production were assessed. The proposed methods are based on the use of the following enzymes: Dispase II, collagenase I/ethylenediaminetetraacetic acid (EDTA), collagenase II/EDTA, and mechanical perforation using DermaRoller and mesh dermatome. The obtained ADMs were examined (both on the side of the basement membrane and on the "cut-off" side) by means of scanning electron microscopy, immunohistochemistry tests and strength tests. ADM was revitalized with human fibroblasts and keratinocytes. The ability of in-depth revitalization of cultured fibroblasts and their ability to secrete collagen IV was examined. The obtained results indicate that the optimal method of production of live skin substitutes is the colonization of autologous fibroblasts and keratinocytes on the scaffold obtained using two-step incubation method: Trypsin/EDTA and dispase II.

Evaluation of the impact of decellularization and sterilization on tensile strength transgenic porcinedermal dressings.

PURPOSE: The aim of this paper was to evaluate which method of acellularization and sterilization is optimal, in the meaning of which processes have the least impact on the deterioration of mechanical properties of porcine tissues used for xenogeneic applications. METHODS: The static tensile probe was conducted for 80 skin specimens obtained from transgenic swine, which are used as a wound dressing for skin recipient. Obtained data were subsequently analyzed with the use of statistical methods. RESULTS: It was found that Young's modulus for the samples after the sterilization process for the dispase substance and the mixed method (SDS + trypsin) were statistically significantly changed. In the case of dispase, Young's modulus value before the sterilization process was 12.4 MPa and after the value increased to 28.0 MPa. For the mixed method (SDS + trypsin) before the sterilization process Young's modulus value was 5.6 MPa and after it was increased to 6.3 MPa. The mixed method (SDS + trypsin) had the slightest effect on changing the mechanical properties of the samples before and after the sterilization process. CONCLUSIONS: It was confirmed that different methods of acellularization and the process of sterilization have an influence on the change of mechanical properties of the skin of transgenic swine. In the authors' opinion, the mixed method (SDS + trypsin) should be recommended as the best one for the preparation of transgenic porcine dermal dressings because it ensures a smaller probability of dressing's damage during a surgical procedure.

Heterogeneous Mixture of Amniotic Cells is Likely a Better Source of Stem Cells than Adipose Tissue.

Stem cells are increasingly being used in the course of burn treatment. As several different types of stem cells are available for the purposes, it is important to chose the most efficient and the most practicable stem cell type. The aim of this study was to compare the potential of heterogeneous amnion cell mixture with the presently used standard therapy, the adipose tissue-derived stem cells. The placenta was collected during a Cesarean section procedure. Adipose tissue tissue-derived cells were isolated using the Cytori's Celution® System. Cells were tested for fulfillment of the minimum criteria for stem cells. The efficiency of cell cultures was tested by an analysis of population doubling, cell proliferation, cell cycle and cell migration. Amniotic cells presented a higher ability for differentiation to chondrocytes and osteocytes than adipose-derived regenerative cells but a lower ability for differentiation toward adipocytes. Additionally, in vitro experiments have demonstrated a higher applicability of amniotic cells than adipose tissue-derived stem cells. Amniotic cells show several advantages: easy access to placenta, low costs and a lack of ethical dilemmas related to stem cell harvesting. The main disadvantage is, however, their availability, as isogenic treatment would only be possible for women around children-bearing age, unless personalized banks for amniotic cells would be established.

Fibroblast and keratinocyte crosstalk: the effect of a poly(tri[ethylene glycol] ethyl ether methacrylate) thermoresponsive surface on short-term co-culture.

The treatment of difficult-to-treat wounds can be challenging. Although a number of approaches have been investigated, the healing process may be slow and unsatisfactory. An alternative approach is the use of a continuous sheet of skin cells applied over a wound which may improve cell implantation and patient recovery. To analyse the gene expression profile of fibroblast/keratinocyte co-culture on poly(tri[ethylene glycol] ethyl ether methacrylate) (P[TEGMA-EE]), a thermoresponsive biocompatible surface. Cultures were grown for 72 hours as a continuous layer on P(TEGMA-EE). Assays for genotoxicity, cell morphology, and fluorescence-assisted flow cytometry were performed to exclude adverse effects. A gene expression profile related to the extracellular matrix was investigated by microarray analysis. For fibroblast monocultures and fibroblast/keratinocyte co-cultures maintained for 72 hours on P(TEGMA-EE), no change in morphology or specific surface markers, or DNA damage (comet assay) was observed, relative to control surface. Moreover, no detrimental impact was ascertained based on microarray analysis. In response to lowered temperature, the detachment of a continuous cell layer sheet from the thermoresponsive surface was observed. When gene expression was compared between fibroblasts cultured alone and co-cultured with keratinocytes on P(TEGMA-EE), 10 genes were shown to be differentially expressed. Of these genes, six were significantly differentially expressed between cultures grown on P(TEGMA-EE) and human skin samples. Our results indicate that P(TEGMA-EE) is fully biocompatible and is therefore a suitable surface for successful preparation and recovery of two-layered fibroblast/keratinocyte co-culture as a continuous sheet of cells.