Storage media and temperature maintain normal anatomy of cadaveric human skin for transplantation to full-thickness skin wounds

A Study of Cadaveric Skin Graft Harvest and Usage: An Observational Prospective Pilot Study

Background Burn injuries pose a significant global public health challenge, causing substantial morbidity and mortality, particularly in low- and middle-income countries. Timely and effective wound coverage is critical in treating severe burns to prevent infection, reduce pain, and promote healing. Cadaveric skin grafts (allografts) have become essential in treating extensive burn wounds, serving as temporary biological dressings to prepare the wound bed for autografting. This study aims to comprehensively analyze the process of cadaveric skin graft harvest and usage in a tertiary care setting. It seeks to evaluate the procedures, challenges, and outcomes associated with cadaveric skin grafts, contributing to optimizing burn care practices and improving patient outcomes. Methods  This observational study was conducted at a tertiary care hospital and burns center with a skin bank, involving 44 cadaveric skin graft harvests and 27 applications between July 1, 2011, and June 30, 2013. The study focused on prospective donors and recipients needing cadaveric skin grafts. Inclusion criteria for donors included consent from the next of kin and the absence of infections or septicemia, while exclusion criteria included prolonged post-mortem intervals and medico-legal cases. The procedures adhered to the Euro Skin Bank protocols, encompassing retrieval, processing, storage, and usage. Data were analyzed using Epi-Info version 7.2.1 software, employing descriptive statistics for categorical variables. Ethical clearance was obtained from the university ethical committee, with mandatory written informed consent for skin donation. Results Out of 519 deaths in the tertiary care hospital, significant barriers to skin donation included septicemia, skin changes, late reporting, young age, medico-legal issues, and positive viral markers. Notably, 114 (21.97%) of next of kin refused consent. Cadaveric skin was harvested in five (11.36%) cases, with potential donors identified in 78 (15.02%) of deaths. Donors were predominantly older males, with efficient procurement processes ensuring timely harvests. The tertiary burns center facilitated 39 (88.63%) cases of cadaveric skin harvests with a skin bank, either at the donor's home or other hospitals notified to the burns center. Cadaveric skin grafts were applied in 27 cases, primarily for burns, with high graft uptake observed over 10 days. Non-healing ulcers showed 100% graft uptake. The survival rate among burn patients was 20 (74%), with deaths mainly due to sepsis and multi-organ failure. Significant barriers to obtaining consent included a lack of awareness, superstitions, social stigmas, and religious objections. Conclusion  The study highlights the critical role of cadaveric skin in managing extensive wounds, particularly burns. Despite challenges in obtaining consent and limited donor availability, cadaveric skin grafts effectively prepared wound beds for autografting, contributing to improved patient outcomes. Increasing community awareness and addressing superstitions and social stigmas are essential for improving donation rates.

Skin Substitutes and Autograft Techniques: Temporary and Permanent Coverage Solutions

Coverage of burn wounds is crucial to prevent sequalae including dehydration, wound infection, sepsis, shock, scarring, and contracture. To this end, numerous temporary and permanent options for coverage of burn wounds have been described. Temporary options for burn coverage include synthetic dressings, allografts, and xenografts. Permanent burn coverage can be achieved through skin substitutes, cultured epithelial autograft, ReCell, amnion, and autografting. Here, we aim to summarize the available options for burn coverage, as well as important considerations that must be made when choosing the best reconstructive option for a particular patient.

Challenges in the Management of Large Burns

Large burns provoke profound pathophysiological changes. Survival rates of patients with large burns have improved significantly with the advancement of critical care and adaptation of early excision protocols. Nevertheless, care of large burn wounds remains challenging secondary to limited donor sites, prolonged time to wound closure, and immunosuppression. The development of skin substitutes and new grafting techniques decreased time to wound closure. Individually, these methods have limited success, but a combination of them may yield more successful outcomes. Early identification of patients with likely poor prognosis should prompt goals of care discussion and involvement of a palliative care team when possible.

Sterilized human skin graft with a dose of 25 kGy provides a privileged immune and collagen microenvironment in the adhesion of Nude mice wounds

This study aimed to report the effects of different doses of ionizing radiation on inflammatory and repair stage of human skin graft adherence in Nude mice wounds. Animals were divided into transplanted with irradiated human skin grafts (IHSG) at 25 and 50 kGy (IHSG 25 kGy; IHSG 50 kGy) and non-IHSG and euthanized on the 3rd, 7th and 21st days after the surgery, by gross and microscopic changes, immunostaining for human type I collagen (Col I) and mouse Col I and Col III and inflammatory cells. We found an effectiveness of human split-thickness graft adherence in mice transplanted with IHSG 25 kGy, as well decrease in dermo-epidermal necrosis and neutrophils, lower loss of skin thickness, epithelization and neo-vascularization. Day 21 post-transplantation with IHSG 25 kGy was observed a well-preserved human skin in the border of the graft, a prominent granulation tissue in an organization by proliferated fibroblasts, Col III deposition and increased B-cells and macrophages. A complete adherence of human skin graft occurred with IHSG 25 kGy. We suggest that the ionizing radiation at 25 kGy mediates inflammation and the repair stage of human skin graft adherence in murine model, thus emerging as a potential tool in healing cutaneous wounds.

Split-Thickness Skin Grafting: A Primer for Orthopaedic Surgeons

Soft-tissue defects pose a unique challenge to the treating orthopaedic surgeon. Such defects are commonly encountered after orthopaedic injuries or infection, and the management of these wounds varies significantly. Skin grafting has gained popularity in the management of such soft-tissue defects due to its ability to provide coverage, re-epithelialize, and have a relatively high success rate. One of the most frequently used types of skin graft in orthopaedics is the split-thickness skin graft (STSG). Understanding the proper indications, technique, and management of the STSG foreshadows its success or failure. This review focuses on the indications, technique, alternatives, and complications surrounding the utilization of the STSG in the management of orthopaedic injuries.

Concise Review: Considering Optimal Temperature for Short-Term Storage of Epithelial Cells

Transplantation of novel tissue-engineered products using cultured epithelial cells is gaining significant interest. While such treatments can readily be provided at centralized medical centers, delivery to patients at geographically remote locations requires the establishment of suitable storage protocols. One important aspect of storage technology is temperature. This paper reviews storage temperature for above-freezing point storage of human epithelial cells for regenerative medicine purposes. The literature search uncovered publications on epidermal cells, retinal pigment epithelial cells, conjunctival epithelial cells, corneal/limbal epithelial cells, oral keratinocytes, and seminiferous epithelial cells. The following general patterns were noted: (1) Several studies across different cell types inclined toward 4 and 16°C being suitable short-term storage temperatures. Correspondingly, almost all studies investigating 37°C concluded that this storage temperature was suboptimal. (2) Cell death typically escalates rapidly following 7–10 days of storage. (3) The importance of the type of storage medium and its composition was highlighted by some of the studies; however, the relative importance of storage medium vs. storage temperature has not been investigated systematically. Although a direct comparison between the included investigations is not reasonable due to differences in cell types, storage media, and storage duration, this review provides an overview, summarizing the work carried out on each cell type during the past two decades.

Awareness and attitude of general population regarding allograft skin donation in Riyadh, Saudi Arabia: Cross-sectional study

INTRODUCTION

Burns are one of the major health issues that considerably affect variable groups of the population, varying in age and severity. Despite advances in burn surgical and non-surgical treatments, patient's appearance still represents public health issue. In regards to surgical treatment of burns, skin grafting is still considered the gold standard. One of the major burdens in the burn surgical treatments is the availability of the skin for grafting. As for the non-surgical treatment different modalities of skin dressings or substitutes are still available as an option.

METHODS

A validated questionnaire based study was utilized to acquire assessment of the overall general population knowledge, awareness and attitude toward skin donation. In addition, it surveyed community personal willingness to donate their skin to a skin bank after being deceased, to help solve skin shortages due to the lack of skin banks in Saudi Arabia.

RESULTS

A total of 698 individuals completed the questionnaire over the period of 5 months, from February 2018 till June 2018. Married, postgraduate females, with a history of burn in close family members or similar individuals showed a positive attitude toward skin donation. However, 22% of the participants did not agree to donate their skin due to religious reasons.

CONCLUSION

The study concluded that the majority of participants were willing to donate their skin, and they were aware of the concept of skin donation and its crucial importance in surgical burn management. The current study showed the majority of participants were aware of skin donation and skin use for burn treatment, in addition to having positive attitude toward skin donation. Men were more aware than the women of skin donation. Religious concern was a major reason for participants' skin donation refusal, an issue that can be addressed by contacting Islamic scholars to issue a Fatwa approving the cause.

Assessment of cryopreserved donor skin viability: the experience of the regional tissue bank of Siena

Skin allografts from cadaver donors are an important resource for treating extensive burns, slow-healing wounds and chronic ulcers. A high level of cell viability of cryopreserved allografts is often required, especially in burn surgery, in Italy. Thus, we aimed to determine which conditions enable procurement of highly viable skin in our Regional Skin Bank of Siena. For this purpose, we assessed cell viability of cryopreserved skin allografts procured between 2011 and 2013 from 127 consecutive skin donors, before and after freezing (at day 15, 180, and 365). For each skin donor, we collected data concerning clinical history (age, sex, smoking, phototype, dyslipidemia, diabetes, cause of death), donation process (multi-tissue or multi-organ) and timing of skin procurement (assessment of intervals such as death-harvesting, harvesting-banking, death-banking). All these variables were analysed in the whole case study (127 donors) and in different groups (e.g. multi-organ donors, non refrigerated multi-tissue donors, refrigerated multi-tissue donors) for correlations with cell viability. Our results indicated that cryopreserved skin allografts with higher cell viability were obtained from female, non smoker, heartbeating donors died of cerebral haemorrhage, and were harvested within 2 h of aortic clamping and banked within 12 h of harvesting (13-14 h from clamping). Age, cause of death and dyslipidaemia or diabetes did not appear to influence cell viability. To maintain acceptable cell viability, our skin bank needs to reduce the time interval between harvesting and banking, especially for refrigerated donors.

Development of the mechanical properties of engineered skin substitutes after grafting to full-thickness wounds

Engineered skin substitutes (ESSs) have been reported to close full-thickness burn wounds but are subject to loss from mechanical shear due to their deficiencies in tensile strength and elasticity. Hypothetically, if the mechanical properties of ESS matched those of native skin, losses due to shear or fracture could be reduced. To consider modifications of the composition of ESS to improve homology with native skin, biomechanical analyses of the current composition of ESS were performed. ESSs consist of a degradable biopolymer scaffold of type I collagen and chondroitin-sulfate (CGS) that is populated sequentially with cultured human dermal fibroblasts (hF) and epidermal keratinocytes (hK). In the current study, the hydrated biopolymer scaffold (CGS), the scaffold populated with hF dermal skin substitute (DSS), or the complete ESS were evaluated mechanically for linear stiffness (N/mm), ultimate tensile load at failure (N), maximum extension at failure (mm), and energy absorbed up to the point of failure (N-mm). These biomechanical end points were also used to evaluate ESS at six weeks after grafting to full-thickness skin wounds in athymic mice and compared to murine autograft or excised murine skin. The data showed statistically significant differences (p <0.05) between ESS in vitro and after grafting for all four structural properties. Grafted ESS differed statistically from murine autograft with respect to maximum extension at failure, and from intact murine skin with respect to linear stiffness and maximum extension. These results demonstrate rapid changes in mechanical properties of ESS after grafting that are comparable to murine autograft. These values provide instruction for improvement of the biomechanical properties of ESS in vitro that may reduce clinical morbidity from graft loss.

Closure of the excised burn wound: temporary skin substitutes

Prompt excision of major burn wounds has been repeatedly shown to improve survival, speed closure, and reduce infection. Immediate coverage with autograft skin is the preferred method of definitive closure of these wounds. However, when harvesting of donor skin is unavailable, or wounds are not ready for autografting, temporary closure with a variety of products can help reduce evaporative loss, prevent infection, and ameliorate pain and metabolic stress. Fresh cadaver allograft is the gold standard for such closure, but other products, including frozen cadaver skin, xenografts, and several synthetic products, are also available. This article reviews the physiology, and types of products, and their uses.

Human Skin Preserved Long-Term in Anhydric Pulverized Sodium Chloride Retains Cell Molecular Structure and Resumes Function After Transplantation

BACKGROUND

Human skin is needed to cover large areas of the body lost through burns, trauma, and extensive maxillofacial surgery. Contemporary methods of skin storage are limited by the period of preservation to a few days. Our previous findings showed that fixation and storage of human skin in anhydric sodium chloride at room temperature for weeks or months preserves its morphological and molecular structure. In this study, we examined whether skin grafts preserved in sodium chloride may be successfully transplanted.

METHODS

Skin was harvested from lower limbs of patients during elective surgery, placed in containers with anhydric salt powder, and kept at 22 degrees C for 3 to 12 weeks. Desalination and rehydration took place before transplantation. Desalinated fragments were transplanted onto the dorsum of scid mice.

RESULTS

All grafts were accepted by recipients. Three weeks after transplantation, keratinocytes synthesized keratins 10, 16, and 17 and expressed antigens specific for stem (p63) and transient (CD29) cells. Moreover, they proliferated vigorously, their basal layer cells incorporated bromdeoxyuridine and expressed proliferative cell nuclear antigen. Isolated from transplants and cultured in vitro, they remained viable and produced enzymes. Dermis retained its structure and expressed fibroblast-specific antigen. All graft cells remained human leukocyte antigen I.

CONCLUSION

Human skin preserved in anhydric sodium chloride at room temperature for months can be successfully transplanted to scid mice. We propose the concept of "spore-like" keratinocyte stem cells to explain the long-term ex vivo survival of keratinocytes. The mechanism of survival of fibroblasts remains to be determined.

Classification and pathophysiology of skin grafts

Flaps and grafts are the 2 main surgical procedures to repair losses of skin tissue. A flap is a full-thickness portion of skin sectioned and isolated peripherally and in depth from the surrounding skin, except along one side, called the peduncle. A graft is a section of skin, of variable thickness and size, completely detached from its original site and moved to cover the zone to be repaired. According to their thickness, skin grafts are classified as split thickness (or partial) and full thickness. The former is further divided into thin, intermediate and thick. Split-thickness skin grafts usually take well, whereas a full-thickness graft only takes if it is relatively small. Grafts are also divided, on the basis of their origin, into the following: autografts, when the donor and recipient are the same individual; homografts, when the donor and recipient are different subjects belonging to the same species; hetero- or xenografts, when the donor and recipient belong to different species. Only autografts can take, whereas homo- and heterografts are rejected. Homo- and heterografts, however, can be useful in particular conditions, for example, extensive burns, because they temporarily ensure vital skin functions.

Skin grafts and skin flaps in the horse

Although most equine wounds can be easily treated and heal without consequence, there are many that present special challenges. Skin grafts area valuable part of the veterinarian's armamentarium for treatment of complicated wounds, particularly limb wounds. Attention to preparation of the recipient site and proper aftercare are critical to successful grafting. With better understanding of equine wound and graft physiology and the promise foretold by advances in human skin grafting, the outcome of treatments of difficult equine wounds should continue to improve in the future.

Rabbit and pig ear skin sample cryobanking: effects of storage time and temperature of the whole ear extirpated immediately after death

The post-mortem temporal and thermal limits within which there will be ample guarantees of rescuing living skin cells from dead specimens of two species, rabbit and pig, were studied. Post-mortem extirpated whole ears were stored (in non-aseptic conditions) either at 4 degrees C or at room temperature (from 22 to 25 degrees C) or at 35 degrees C for different time lapses after animal death. In both species, the post-mortem maximum time lapses where cell viability was not significantly reduced were 240, 72, and 24 h post-mortem (hpm) for 4, 22-25 and 35 degrees C, respectively. Once the post-mortem temporal limits for each tested thermal level at which cells from skin samples are able to grow in culture were defined, the survival ability of skin samples submitted to these temporal limits and cryopreserved were tested. In the pig, skin samples stored at the three tested thermal levels survived after vitrification-warming, reaching confluence in culture. In rabbit, only tissue samples from ears stored at 35 degrees C for 24 hpm did not survive after vitrification-warming. In conclusion, we should remark that cell survival rates obtained according to the assayed post-mortem time lapses and thermal levels are sufficient to collect and to cryopreserve skin samples from the majority of dead specimens.