Novel expansion techniques for skin grafts

Paris polyphylla Sm. characterized extract infused ointment accelerates diabetic wound healing in In-vivo model

ETHNOPHARMACOLOGICAL RELEVANCE

The dried rhizome of Paris polyphylla Sm. is extensively used by traditional healers in India, China, and Vietnam to treat skin inflammation, cut wounds, uterine and traumatic bleeding, and cancer.

AIM OF THE STUDY

The traditional use of P. polyphylla rhizomes for treating wounds and bleeding has been reported previously. However, the potential of P. polyphylla in the treatment of diabetic wounds has not yet been explored. Our present study focused on the investigation of the wound-healing activity of P. polyphylla infused ointment in streptozotocin (STZ)-induced diabetic rats to validate the traditional claim.

MATERIALS AND METHODS

Hydroalcoholic extract of the dried rhizomes of P. polyphylla were quantified by validated and optimized HPTLC (High-performance thin layer chromatography) method for Paris saponin VII, Dioscin and Polyphyllin V. The extract was used to prepare P. polyphylla ointments (5 and 10%). P. polyphylla ointment was subjected to physiochemical analysis and skin irritation test. Thirty STZ-induced diabetic adult male Wistar albino rats were divided into five groups (n = 6) and a circular excision wound was created. P. polyphylla ointment, ointment base (OB), and standard (STD) (Povidone Iodine 10%) were administered topically. The wound area of all groups were recorded every six days and compared with that of control. The epithelization period of each group was recorded. On day 18, the histopathological study of skin tissues of all groups was performed using hematoxylin and eosin (H&E) and Mallory's trichrome (MT).

RESULTS

Marker analysis and quantification of phytomolecules in hydroalcoholic extract ofP. Polyphylla were found to be of paris saponin VII (3.28 ± 0.08% w/w), dioscin (1.94 ± 0.12% w/w), and polyphyllin V (1.87 ± 0.84% w/w). A physiochemical study of P. polyphylla ointment showed that the prepared ointment was within an acceptable range and was not irritable to the skin. Daily topical administration of 10% P. polyphylla ointment (PP10) for 18 days completely healed the STZ-induced diabetic wounds. On day 18, the 5% P. polyphylla ointment (PP5) showed 99.1 ± 2.9% wound closure, while that of the standard and control was 78.4 ± 7.3% and 18.5 ± 5.9%, respectively. The epithelialization period of PP10 was 18 days, whereas that of the control was 28 days. Histopathological analysis of the progression of PP10 and PP5 wounds showed a decrease in inflammatory cells, regenerated epithelial layer, keratosis layer, hair follicles, fibroblasts, and collagen. Upon collagen intensity quantification of MT stained sections, an increase in collagen density of PP10 and PP5 treated groups was observed, showing accelerated wound healing potential of P. polyphylla extract in diabetic wounds compared to the standard ointment.

CONCLUSION

This study suggested the potential of P. polyphylla rhizomes derived formulation to treat diabetic wounds, although the plant is traditionally used to treat normal wounds. The results indicate the validation of traditional claim, which has been explored commercially in industrial aspect.

Full-thickness skin columns: A method to reduce healing time and donor site morbidity in deep partial-thickness burns

The current standard of care for the coverage of large wounds often involves split thickness skin grafts (STSGs) which have numerous limitations. One promising technique that has gained traction is fractional autologous skin grafting using full-thickness skin columns (FTSC). Harvesting occurs orthogonally by taking numerous individual skin columns containing the epidermis down through the dermis and transferring them to the wound bed. The purpose of this porcine study was to investigate the efficacy of implanting FTSCs directly into deep partial-thickness burn wounds, as well as examining donor site healing at the maximal harvest density. It was hypothesised that by utilising FTSCs, the rate of healing in deep partial thickness burns can be improved without incurring the donor morbidity seen in other methods of skin grafting. Deep partial-thickness burns were created on the dorsum of female red duroc swine, debrided 3 days later and FTSCs were implanted at varying expansion ratios directly into the burn wounds. At day 14, 1:50 expansion ratio showed significantly faster re-epithelialisation compared to the debrided burn control and 1:200. Donor sites (at 7%-10% harvest density) were 100% re-epithelialised by day 7. Additionally, the maximal harvest density was determined to be 28% in an ex vivo model, which then five donor sites were harvested at 28% density on a red duroc swine and compared to five STSG donor sites. At maximal harvest density, FTSC donor sites were significantly less hypopigmented compared to STSGs, but no significant differences were observed in re-epithelialisation, contraction, blood flow or dermal thickness. In conclusion, implantation directly into deep partial-thickness burns is a viable option for the application of FTSCs, favouring lower expansion ratios like 1:50 or lower. Little difference in donor site morbidity was observed between FTSC at a maximal harvest density of 28% and STSGs, exceeding the optimal harvest density.

Meek Micro-Skin Grafting and Acellular Dermal Matrix in Pediatric Patients: A Novel Approach to Massive Extravasation Injury

(1) Background: Extravasation injuries in pediatric patients can lead to significant harm if they are not promptly diagnosed and treated. However, evidence-based standardization on extravasation management remains limited, particularly for extensive wound necrosis. This case report presents the management of an 8-week-old premature patient with an extensive extravasation injury involving the right forearm and dorsum of the hand. (2) Methods: The patient was evaluated by a multidisciplinary team in our Neonatal Intensive Care Unit. Surgical intervention involved the debridement of necrotic tissues, followed by temporary coverage with an acellular dermal matrix. Definitive coverage was achieved through Meek micrografting after three weeks. Physical therapy was provided with pre- and post-rehabilitation range of motion assessed using goniometric measurements. Scar quality was evaluated using the Vancouver Scar Scale. (3) Results: The engraftment rate of the Meek micrografts was 93%, with 16 out of 226 micrografts lost. The patient achieved a Vancouver Scar Scale score of 6, indicating a moderate degree of scarring. Significant improvements in elbow, wrist, and finger joint range of motion were observed at a 1-year follow-up. (4) Conclusions: Close observation and heightened awareness of extravasation risks by trained personnel are crucial. Meek micrografting combined with dermal substitute coverage represents an innovative approach to managing extravasation wounds in pediatric patients.

Fractional Epidermal Skin Grafts in Hard-to-Heal Wounds: Case Series

Cellutome^™ is a minimally invasive, automated system for harvesting fractional epidermal micrografts. This therapy is indicated for granulating, small size, poor exuding acute wounds. We enrolled 15 patients with 9 venous leg ulcers and 6 atypical ulcers. The micrografts were applied with a nonadherent dressing and covered with a polyurethane foam and multilayer bandage. We scheduled 3 weekly visits for the change of the secondary dressings and multilayer bandage and clinical assessment (Wound Bed Score [WBS], pain assessment, and healing rate). The lesions were measured with the Silhouette Star^™ system, a software that allows measurement of perimeter and area from a digital image. The only symptom during the procedure was a sensation of warmth. The donor area healed in 2 weeks in all patients (n = 15). We reported an area reduction of 24.30% in typical ulcers and 38.82% in atypical ulcers after 3 weeks. The average WBS improved in all ulcers from 13.06 to 14.93. The average healing rate was 0.19 mm/day both in typical and atypical ulcers. Consequently, in our small case series fractionated epidermal graft treatment significantly promoted the healing rate in all chronic ulcers regardless of etiology. Future studies with larger case series will be needed.

Retrospectives on Three Decades of Safe Clinical Experience with Allogeneic Dermal Progenitor Fibroblasts: High Versatility in Topical Cytotherapeutic Care

Allogeneic dermal progenitor fibroblasts constitute cytotherapeutic contenders for modern cutaneous regenerative medicine. Based on advancements in the relevant scientific, technical, and regulatory fields, translational developments have slowly yet steadily led to the clinical application of such biologicals and derivatives. To set the appropriate general context, the first aim of this study was to provide a current global overview of approved cell and gene therapy products, with an emphasis on cytotherapies for cutaneous application. Notable advances were shown for North America, Europe, Iran, Japan, and Korea. Then, the second and main aim of this study was to perform a retrospective analysis on the various applications of dermal progenitor fibroblasts and derivatives, as clinically used under the Swiss progenitor cell transplantation program for the past three decades. Therein, the focus was set on the extent and versatility of use of the therapies under consideration, their safety parameters, as well as formulation options for topical application. Quantitative and illustrative data were summarized and reported for over 300 patients treated with various cell-based or cell-derived preparations (e.g., progenitor biological bandages or semi-solid emulsions) in Lausanne since 1992. Overall, this study shows the strong current interest in biological-based approaches to cutaneous regenerative medicine from a global developmental perspective, as well as the consolidated local clinical experience gathered with a specific and safe allogeneic cytotherapeutic approach. Taken together, these current and historical elements may serve as tangible working bases for the further optimization of local and modern translational pathways for the provision of topical cytotherapeutic care.

Expansion of fibroblast cell sheets using a modified MEEK micrografting technique for wound healing applications

Cell sheet engineering, a scaffold-free approach to fabricate functional tissue constructs from several cell monolayers, has shown promise in tissue regeneration and wound healing. Unfortunately, these cell sheets are often too small to provide sufficient wound area coverage. In this study, we describe a process to enlarge cell sheets using MEEK micrografting, a technique extensively used to expand skin autografts for large burn treatments. Human dermal fibroblast cell sheets were placed on MEEK's prefolded gauze without any use of adhesive, cut along the premarked lines and stretched out at various expansion ratios (1:3, 1:6 and 1:9), resulting in regular distribution of many square islands of fibroblasts at a much larger surface area. The cellular processes essential for wound healing, including reattachment, proliferation, and migration, of the fibroblasts on expanded MEEK gauze were superior to those on nylon dressing which served as a control. The optimal expansion ratio with the highest migration rate was 1:6, possibly due to the activation of chemical signals caused by mechanical stretching and an effective intercellular communication distance. Therefore, the combination of cell sheet engineering with the MEEK micrografting technique could provide high quality cells with a large coverage area, which would be particularly beneficial in wound care applications.

Large full-thickness wounded skin regeneration using 3D-printed elastic scaffold with minimal functional unit of skin

Traditional tissue engineering skin are composed of living cells and natural or synthetic scaffold. Besize the time delay and the risk of contamination involved with cell culture, the lack of autologous cell source and the persistence of allogeneic cells in heterologous grafts have limited its application. This study shows a novel tissue engineering functional skin by carrying minimal functional unit of skin (MFUS) in 3D-printed polylactide-co-caprolactone (PLCL) scaffold and collagen gel (PLCL + Col + MFUS). MFUS is full-layer micro skin harvested from rat autologous tail skin. 3D-printed PLCL elastic scaffold has the similar mechanical properties with rat skin which provides a suitable environment for MFUS growing and enhances the skin wound healing. Four large full-thickness skin defects with 30 mm diameter of each wound are created in rat dorsal skin, and treated either with tissue engineering functional skin (PLCL + Col + MFUS), or with 3D-printed PLCL scaffold and collagen gel (PLCL + Col), or with micro skin islands only (Micro skin), or without treatment (Normal healing). The wound treated with PLCL + Col + MFUS heales much faster than the other three groups as evidenced by the fibroblasts migration from fascia to the gap between the MFUS dermis layer, and functional skin with hair follicles and sebaceous gland has been regenerated. The PLCL + Col treated wound heals faster than normal healing wound, but no skin appendages formed in PLCL + Col-treated wound. The wound treated with micro skin islands heals slower than the wounds treated either with tissue engineering skin (PLCL + Col + MFUS) or with PLCL + Col gel. Our results provide a new strategy to use autologous MFUS instead "seed cells" as the bio-resource of engineering skin for large full-thickness skin wound healing.

A Narrative Review of the History of Skin Grafting in Burn Care

Thermal injuries have been a phenomenon intertwined with the human condition since the dawn of our species. Autologous skin translocation, also known as skin grafting, has played an important role in burn wound management and has a rich history of its own. In fact, some of the oldest known medical texts describe ancient methods of skin translocation. In this article, we examine how skin grafting has evolved from its origins of necessity in the ancient world to the well-calibrated tool utilized in modern medicine. The popularity of skin grafting has ebbed and flowed multiple times throughout history, often suppressed for cultural, religious, pseudo-scientific, or anecdotal reasons. It was not until the 1800s, that skin grafting was widely accepted as a safe and effective treatment for wound management, and shortly thereafter for burn injuries. In the nineteenth and twentieth centuries skin grafting advanced considerably, accelerated by exponential medical progress and the occurrence of man-made disasters and global warfare. The introduction of surgical instruments specifically designed for skin grafting gave surgeons more control over the depth and consistency of harvested tissues, vastly improving outcomes. The invention of powered surgical instruments, such as the electric dermatome, reduced technical barriers for many surgeons, allowing the practice of skin grafting to be extended ubiquitously from a small group of technically gifted reconstructive surgeons to nearly all interested sub-specialists. The subsequent development of biologic and synthetic skin substitutes have been spurred onward by the clinical challenges unique to burn care: recurrent graft failure, microbial wound colonization, and limited donor site availability. These improvements have laid the framework for more advanced forms of tissue engineering including micrografts, cultured skin grafts, aerosolized skin cell application, and stem-cell impregnated dermal matrices. In this article, we will explore the convoluted journey that modern skin grafting has taken and potential future directions the procedure may yet go.

Validation of an implantable bioink using mechanical extraction of human skin cells: First steps to a 3D bioprinting treatment of deep second degree burn

Clinical grade cultured epithelial autograft (CEA) are routinely used to treat burns covering more than 60% of the total body surface area. However, although the epidermis may be efficiently repaired by CEA, the dermal layer, which is not spared in deep burns, requires additional treatment strategies. Our aim is to develop an innovative method of skin regeneration based on in situ 3D bioprinting of freshly isolated autologous skin cells. We describe herein bioink formulation and cell preparation steps together with experimental data validating a straightforward enzyme-free protocol of skin cell extraction. This procedure complies with both the specific needs of 3D bioprinting process and the stringent rules of good manufacturing practices. This mechanical extraction protocol, starting from human skin biopsies, allows harvesting a sufficient amount of both viable and growing keratinocytes and fibroblasts. We demonstrated that a dermis may be reconstituted in vitro starting from a medical grade bioink and mechanically extracted skin cells. In these experiments, proliferation of the extracted cells can be observed over the first 21 days period after 3D bioprinting and the analysis of type I collagen exhibited a de novo production of extracellular matrix proteins. Finally, in vivo experiments in a murine model of severe burn provided evidences that a topical application of our medical grade bioink was feasible and well-tolerated. Overall, these results represent a valuable groundwork for the design of future 3D bioprinting tissue engineering strategies aimed at treating, in a single intraoperative step, patients suffering from extended severe burns.

"Tissues in a Dish": A Review of Organoids in Plastic Surgery

Organoids are in vitro miniaturized organ models—or, colloquially, “organs in a dish.” These 3-dimensional, multicellular structures are classically derived from pluripotent or multipotent stem cells. When guided by tissue-specific molecular factors, these cells exhibit self-organizing abilities that allow them to accurately recapitulate the architecture and function of the organ of interest. Organoid technology is a rapidly expanding field that endows researchers with an unprecedented ability to recreate, study, and manipulate complex biologic processes in vitro. When compared with standard 2- and 3-dimensional culture systems, which rely on co-culturing pre-established cell types, organoids provide a more biomimetic model with which to study the intercellular interactions necessary for in vivo organ function and architecture. Organoids have the potential to impact all avenues of medicine, including those fields most relevant to plastic and reconstructive surgery such as wound healing, oncology, craniofacial reconstruction, and burn care. In addition to their ability to serve as a novel tool for studying human-specific disease, organoids may be used for tissue engineering with the goal of developing biomimetic soft-tissue substitutes, which would be especially valuable to the plastic surgeon. Although organoids hold great promise for the field of plastic surgery, technical challenges in creating vascularized, multilineage organoids must be overcome to allow for the integration of this technology in clinical practice. This review provides a brief history of the organoid, highlights its potential clinical applications, discusses certain limitations, and examines the impact that this technology may have on the field of plastic and reconstructive surgery.

Activator Protein-1 Transcriptional Activity Drives Soluble Micrograft-Mediated Cell Migration and Promotes the Matrix Remodeling Machinery

Impaired wound healing and tissue regeneration have severe consequences on the patient's quality of life. Micrograft therapies are emerging as promising and affordable alternatives to improve skin regeneration by enhancing the endogenous wound repair processes. However, the molecular mechanisms underpinning the beneficial effects of the micrograft treatments remain largely unknown. In this study, we identified the active protein-1 (AP-1) member Fos-related antigen-1 (Fra-1) to play a central role in the extracellular signal-regulated kinase- (ERK-) mediated enhanced cell migratory capacity of soluble micrograft-treated mouse adult fibroblasts and in the human keratinocyte cell model. Accordingly, we show that increased micrograft-dependent in vitro cell migration and matrix metalloprotease activity is abolished upon inhibition of AP-1. Furthermore, soluble micrograft treatment leads to increased expression and posttranslational phosphorylation of Fra-1 and c-Jun, resulting in the upregulation of wound healing-associated genes mainly involved in the regulation of cell migration. Collectively, our work provides insights into the molecular mechanisms behind the cell-free micrograft treatment, which might contribute to future advances in wound repair therapies.

Cultured Epidermal Melanocyte Transplantation in Vitiligo: A Review Article

BACKGROUND

The color of the skin is highly heritable but can be influenced by the environments and endocrine factors. Many other factors, sometimes destructive, are also involved in the formation of skin color, which sometimes affects pigmentation patterns. Vitiligo is an autoimmune hypopigmentation painless disorder with appearance of white patches and psychological effects on patients. It is a disease in which melanocytes of the skin are destroyed in certain areas; therefore depigmentation appears.

METHODS

We studied more than 60 articles. Several therapeutic methods have been used to return the color of skin in vitiligo. These methods include non-invasive treatment and surgical techniques. Among all these therapies, cell transplantation is an advanced procedure in regenerative medicine. Extraction of melanocytes from normal skin and then their cultivation in the laboratory provides a large number of these cells, the transplanting of which to depigmentation areas stimulates the site to irreversibly produce melanin.

RESULTS

The transplantation methods of these cells have been evolved over many years and the methods of producing blister have been changed to the injection of these cells to the target sites.

CONCLUSION

In this review, autologous cultured melanocyte transplantation has been considered to be the most viable, safe, and effective method in the history of vitiligo treatments.

New technologies in global burn care - a review of recent advances

There have been truly incredible strides in the standard of burn care. The mortality from burn injuries has more than halved since the 1950s, making it hugely unique among major diseases of the developed world. There can be no doubt technology and technological advances have driven this process, dramatically improved every aspect of burn care, from the intensive care management, the surgical management, management of the healing wound to the post burn sequelae, specifically scar management. This review aims to identify key technological advances in burns, in both the developed and developing world, and evaluate their influence in the continued strategy to improve the standards of global burn care.

Split-thickness skin grafting: early outcomes of a clinical trial using different graft thickness

OBJECTIVE

In clinical practice, split-thickness skin graft (STSG) transplantation remains the gold standard for covering large skin defects. Currently, there is no consensus on the optimal thickness of skin grafts. The purpose of our study was to compare the early healing processes of recipient and donor wounds after STSG transplantation using grafts of different thickness.

METHOD

This prospective, randomised clinical trial included 84 patients that underwent STSG transplantation surgery for post-burn, post-traumatic or postoperative skin defects. Patients were randomised to receive a skin graft of either 0.2mm, 0.3mm or 0.4mm thickness. After skin transplantation, the wound healing parameters of both the recipient and donor wounds were evaluated after three days, one week, two weeks and one month.

RESULTS

The greatest mean epithelialisation scores and highest rate of complete wound epithelialisation were identified in the recipient and donor wounds of the 0.2mm transplant group, at all time points. When the recipient wound pain scores were evaluated, the greatest visual analogue scale (VAS) values were found in the 0.2mm transplant group. The opposite result was found for the donor wound, where the highest VAS scores were identified in the 0.4mm transplant group. There were no significant differences, at any follow-up period, when wound secretion, erythema, swelling, localised warmth and fluctuation were compared.

CONCLUSION

The early healing of recipient wounds after STSG transplantation with grafts of various thickness differed considerably, especially regarding wound epithelialisation and pain.

Advances in keratinocyte delivery in burn wound care

This review gives an updated overview on keratinocyte transplantation in burn wounds concentrating on application methods and future therapeutic cell delivery options with a special interest in hydrogels and spray devices for cell delivery. To achieve faster re-epithelialisation of burn wounds, the original autologous keratinocyte culture and transplantation technique was introduced over 3 decades ago. Application types of keratinocytes transplantation have improved from cell sheets to single-cell solutions delivered with a spray system. However, further enhancement of cell culture, cell viability and function in vivo, cell carrier and cell delivery systems remain themes of interest. Hydrogels such as chitosan, alginate, fibrin and collagen are frequently used in burn wound care and have advantageous characteristics as cell carriers. Future approaches of keratinocyte transplantation involve spray devices, but optimisation of application technique and carrier type is necessary.