Early graft-infiltrating lymphocytes are not associated with graft rejection in a mouse model of skin transplantation.

Graft-infiltrating lymphocytes (GILs) play an important role in promoting rejection after organ transplantation. We recently reported that GILs that accumulated up to 3 days post-transplantation did not promote rejection, whereas GILs present 3-5 days post-transplantation promoted rejection in a mouse heart transplantation model. However, the immunological behaviour of GILs in murine skin transplantation remains unclear. GILs were isolated on days 3, 5 or 7 post-transplantation from C57BL/6 (B6) allogeneic skin grafts transplanted onto BALB/c mice. BALB/c Rag2-/- γc-/- mice (BRGs) underwent B6 skin graft transplantation 10 weeks after adoptive transfer of day 3, 5, or 7 GILs. BRGs reconstituted with day 5 or 7 GILs completely rejected B6 grafts. However, when B6 grafts harvested from recipient BALB/c mice on day 5 or 7 were re-transplanted into BRGs, half of the re-transplanted day 5 grafts established long-term survival, although all re-transplanted day 7 grafts were rejected. BRGs reconstituted with day 3 GILs did not reject B6 grafts. Consistently, re-transplantation using day 3 skin grafts resulted in no rejection. Administration of anti-CD25 antibodies did not prevent the phenomenon observed for the day 3 skin grafts. Furthermore, BRGs reconstituted with splenocytes from naïve BALB/c mice immediately rejected the naïve B6 skin grafts and the re-transplanted day 3 B6 grafts, suggesting that day 3 GILs were unable to induce allograft rejection during the rejection process. In conclusion, the immunological role of GILs depends on the time since transplantation. Day 3 GILs had neither protective nor alloreactive effects in the skin transplant model.

Postoperative Time and Anatomic Location Influence Skin Graft Reperfusion Assessed With Laser Speckle Contrast Imaging.

OBJECTIVES: Under optimal conditions, afferent and efferent human skin graft microcirculation can be restored 8-12 days postgrafting. Still, the evidence about the reperfusion dynamics beyond this period in a dermato-oncologic setting is scant. We aimed to characterise the reperfusion of human skin grafts over 4 weeks according to the necrosis extension (less than 20%, or 20%-50%) and anatomic location using laser speckle contrast imaging (LSCI). METHODS: Over 16 months, all eligible adults undergoing skin grafts following skin cancer removal on the scalp, face and lower limb were enroled. Perfusion was assessed with LSCI on the wound margin (control skin) on day 0 and on the graft surface on days 7, 14, 21 and 28. Graft necrosis extension was determined on day 28. RESULTS: Forty-seven grafts of 47 participants were analysed. Regardless of necrosis extension, graft perfusion equalled the control skin by day 7, surpassed it by day 21, and stabilised onwards. Grafts with less than 20% necrosis on the scalp and lower limb shared this reperfusion pattern and had a consistently better-perfused centre than the periphery for the first 21 days. On the face, the graft perfusion did not differ from the control skin from day 7 onwards, and there were no differences in reperfusion within the graft during the study. CONCLUSION: Skin graft reperfusion is a protracted process that evolves differently in the graft centre and periphery, influenced by postoperative time and anatomic location. A better knowledge of this process can potentially enhance the development of strategies to induce vessel ingrowth into tissue-engineered skin substitutes.

Organization of Hannover Skin Bank: Sterile culture and procurement protocols for viable cryopreserved allogeneic skin grafts of living donors.

Preserved allogeneic donor skin still represents one of the gold standard therapies in temporary wound coverage in severely burned patients or chronic wounds. Allogeneic skin grafts are currently commercially available as cryo- or glycerol-preserved allografts through skin tissue banks all over the world. Most of the skin tissue banks rely on human cadaveric skin donations. Due to the chronic shortage of human allogeneic transplants, such as skin, and increasing costs in the procurement of allografts from other skin tissue banks, Hannover Medical School has been building up its own skin tissue bank based on allogeneic skin grafts from living donors who underwent surgical treatment (i.e., body-contouring procedures, such as abdominioplasties). This article presents procedures and protocols for the procurement and processing of allogeneic skin grafts according to national legislation and European regulations and guidelines. Beside protocols, initial microbiological data regarding the sterility of the harvested grafts are presented. The results currently form the basis for further investigations as well as clinical applications. In summary, a microbiological testing and acceptance procedure is presented that ensures adequate patient safety and skin viability.

The role of split-thickness skin grafting in the treatment of vasculitic and pyoderma gangrenosum ulcers in a multidisciplinary wound centre.

Vasculitic and pyoderma gangrenosum ulcers are traditionally treated with immunosuppressants, and the role of surgery in the treatment of these atypical ulcers remains unclear. This study aimed to investigate the need for surgical intervention as well as the outcome and safety of skin grafting in the treatment of 46 patients with vasculitic ulcers and 34 with pyoderma gangrenosum ulcers using data recorded in the validated Wound Registry. Of the 80 patients with atypical ulcers, 14% (n = 11) were treated surgically; these patients were older (p = 0.039), had lower mobility status (p = 0.002), and more often pulmonary diseases, rheumatoid arthritis, and previous arterial procedures (p = 0.007; p = 0.031; p = 0.031, respectively) than those treated conservatively. Of 181 ulcers, 15% (n = 27) were surgically treated, 78% once and 22% multiple times. During follow-up, 92.3% of both surgically and conservatively treated ulcers with available data healed. Of the surgically treated ulcers, median healing time after first surgical procedure was 96 days, and post-surgical complications were considered mild or unrelated to surgery. Our results suggest that if surgery is indicated, skin grafting is a safe and efficient treatment method provided that multidisciplinary approach is applied.

Nail bed trauma reconstruction and artificial nail replacement - a case report.

Nail bed reconstruction is crucial after fingertip trauma, impacting both function and aesthetics. In this article, the authors describe a case of partial distal phalanx amputation of the index finger with laceration of the nail bed's remaining part. A traumatically elevated skin-fat flap covered the exposed bone on the fingertip, preserving finger length and sensitivity on the radial side. A full-thickness skin graft from the forearm closed a secondary defect on the finger pulp. Nail bed suturing prevented scarring and nail deformity, and a temporary artificial plastic nail replacement maintained the nail bed's shape. Temporary artificial nail replacements protect the regenerating fingertip bed, promote healing, and prevent nail deformities. Proper adaptation of lacerated nail bed edges, supported by either the patient's own nail or a temporary artificial nail, is crucial for optimal fingertip restoration, including proper nail shape.

Personalised burn treatment: bedside electrospun nanofibre scaffold with cultured autologous keratinocytes: a case study.

Nearly four decades after cultured epidermal autografts (CEA) were first used for the treatment of extensive burn wounds, the current gold standard treatment remains grafting healthy autologous skin from a donor site to the damaged areas, with current skin substitutes limited in their clinical use. We propose a novel treatment approach, using an electrospun polymer nanofibrous matrix (EPNM) applied on-site directly on the CEA-grafted areas. In addition, we propose a personalised treatment on hard-to-heal areas, in which we spray suspended autologous keratinocytes integrated with 3D EPNM applied on-site, directly onto the wound bed. This method enables the coverage of larger wound areas than possible with CEA. We present the case of a 26-year-old male patient with full-thickness burns covering 98% of his total body surface area (TBSA). We were able to show that this treatment approach resulted in good re-epithelialisation, seen as early as seven days post CEA grafting, with complete wound closure within three weeks, and to a lesser extent in areas treated with cell spraying. Moreover, in vitro experiments confirmed the feasibility of using keratinocytes embedded within the EPNM: cell and culture viability, identity, purity and potency were determined. These experiments show that the skin cells are viable and can proliferate within the EPNM. The results presented are of a promising novel strategy for the development of personalised wound treatment, integrating on-the-spot 'printed' EPNM with autologous skin cells, which will be applied at the bedside, over deep dermal wounds, to accelerate healing time and wound closure.

Effectiveness and Safety of Transplantation of the Stromal Vascular Fraction of Autologous Adipose Tissue for Wound Healing in the Donor Site in Patients with Third-Degree Skin Burns: A Randomized Trial.

Background: The quality of the wound healing at the donor site significantly determines the overall condition of the burn patient, the extent of wound fluid and protein losses, the severity of any systemic in-flammatory reaction, and the intensity of the pain syndrome. It is known that the stromal vas-cular fraction (SVF) has a beneficial effect on the healing of wound defects. This study is aimed at assessing the safety and effectiveness of the application of the SVF of autologous adipose tis-sue to stimulate wound healing of the donor site in patients with burns. Methods: This placebo-controlled clinical study included 38 patients with third-degree thermal skin burns. The patients underwent liposuction, enzymatic isolation of the SVF, and intradermal injection of the preparation into the wounds in the donor site, followed by tewametry, cutome-try, thermography and biopsy after 12 days. Quantitative indicators were compared using the Mann-Whitney test for unrelated groups and the Wilcoxon test for related groups. Spearman's rank correlation coefficient (RS) was used to assess the correlation. Results: Epithelization of the wounds in all patients was seen over an average area of 88 (84;92) %, there being no significant differences between the actual and the control wound sites for this parameter. Transdermal water loss in the test wound sites was 2 times lower than in the control sites (P = 0.001). The wound donor sites regained their temperature distribution faster than the control sites (P = 0.042). Histological preparations of the skin of the wound sites revealed that their epidermal layer was 19% thicker compared to the controls (P = 0.043). It should be noted that five adverse events related to manipulations in the postoperative period were registered. Conclusion: Transplantation of SVF autologous adipose tissue into the wound area in most clinical cases proceeded without complications. The area of epithelialization of wound areas af-ter the introduction of SVF did not change, although a significant decrease in transdermal water loss was observed in the wound areas with an improvement in their thermoregulation and an increase in the thickness of the epidermis.

Evaluation of contraction of the split-thickness skin graft using three dermal matrices in the treatment of burn contractures: A randomised clinical trial.

Burn injuries commonly result in serious sequelae (such as skin contractures) in surviving patients, for which no single optimal solution is known. The goal of this study was to compare the late contraction of autologous skin grafts with or without dermal matrices used in the treatment of patients with burn contractures. This parallel design prospective, randomised and controlled clinical trial included patients with burn contracture treated using autologous skin grafts and dermal matrix. Patients were randomly assigned to one of the four groups: Integra® matrix (n = 10), Pelnac® matrix (n = 10), Matriderm® matrix (n = 9) or a Control Group (n = 10, without dermal matrix, only skin graft). The boundaries of skin defect were marked and transferred to a flat sterile surface for area measurement. The current area of the skin grafts was measured during surgery and compared with those obtained at 1, 3, 6 and 12 months postoperatively. Twelve months after surgery, the Control Group presented lower rates of skin graft contraction than Integra® (p < 0.01), Matriderm® (p = 0.01) and Pelnac® (p < 0.01) groups. Pelnac® resulted in larger skin graft contraction than Matriderm® (p < 0.01) and Integra® (p = 0.02), while differences between Integra® and Matriderm® were not significant (p = 0.16). The comparison between intraoperative and 12 months after surgery showed that the worst mean rates of skin graft contraction were from the Pelnac® (51.79%) and Matriderm® (59.17%). In patients with burn contractures, the use of these three dermal matrices did not reduce or avoid the occurrence of late contraction of the skin graft, so their use for this purpose should be carefully evaluated.

Comparing Flap Advancement and Wound Coverage of Anterograde Homodigital Neurovascular Island Flap Designs: A Cadaveric Model.

PURPOSE: Anterograde homodigital neurovascular island flaps are a reconstructive option for volar fingertip injuries and confer the advantage of preserving fingertip sensation after surgery. However, the amount of flap advancement and wound coverage provided by stepwise and triangular flap designs remains unknown. This study sought to investigate how incremental proximal dissection of the pedicle influences flap advancement and whether advancement and/or coverage differ between the triangular and stepwise flap designs using 22 paired cadaveric digits. METHODS: Flap advancement and wound coverage were evaluated in a pairwise design such that each pair of digits received 1 stepwise flap and 1 triangular flap. After creating a standardized injury to the volar fingertip, pedicled flaps were dissected from the middle phalanx and advanced distally under consistent tension. Advancement was measured for each 5 mm of proximal mobilization of the pedicle to a maximum of 30 mm. RESULTS: On average, 2.6 ± 0.2 mm of flap advancement could be achieved for every 10 mm of pedicle mobilization. With 30 mm of proximal mobilization of the pedicle, 11.8 ± 2.8 mm of advancement and 57.2% ± 16.1% of wound coverage could be expected. There were no significant differences between the flap designs. CONCLUSIONS: The stepwise and triangular anterograde homodigital neurovascular island flaps offer comparable and consistent reconstructive outcomes for volar fingertip injuries. CLINICAL RELEVANCE: The findings in this study suggest that the choice of flap design need not be influenced by the considerations of advancement or coverage; rather, surgeon preference or technical differences between the 2 flap designs may be of more importance.

Negative pressure wound therapy, artificial skin and autogenous skin implantation in diabetic foot ulcers.

OBJECTIVE: Diabetic foot ulcers (DFUs) are one of the most serious diabetic consequences, leading to amputations. Various therapies have been used to treat DFUs; however, a combination of negative pressure suction, artificial skin and autogenous skin implantation have never been investigated. This study aimed to evaluate the effectiveness of a novel three-step therapy protocol using negative pressure wound therapy (NPWT), artificial skin and autogenous skin implantation in patients with DFUs. METHOD: At a single tertiary university hospital between 2015 and 2018, the three-step therapy protocol was applied to patients with DFUs and its safety and efficacy was investigated. RESULTS: A total of 21 patients took part in the study. The majority of the patients were female (62%), with a mean age of 65 years and a mean body mass index of 21kg/m2. A third (n=7) of operative sites experienced minor complications, with two requiring re-operation. At a median follow up of 24 months, the average time of complete wound healing was 46 days, and the wound healing rate was 71%. The first-stage wound healing rate was 90%. All patients had achieved remission without any further recurrence of disease. CONCLUSION: This comprehensive surgical technique for managing DFUs achieved a high local cure rate, minimal functional morbidity, and acceptable wound complication rates. The three-step therapy protocol has the potential to promote the healing process of DFUs, which is expected to serve as a new method for the treatment and cure of DFUs.

Reduced Elastin Fibers and Melanocyte Loss in Vitiliginous Skin Are Restored after Repigmentation by Phototherapy and/or Autologous Minigraft Transplantation.

Vitiligo is a hypopigmentation disease characterized by melanocyte death in the human epidermis. However, the mechanism of vitiligo development and repigmentation is largely unknown. Dermal fiber components might play an important role in vitiligo development and repigmentation. Indeed, our preliminary study demonstrated that elastin fibers were decreased in vitiliginous skin, suggesting that the elastin fiber is one of the factors involved in vitiligo development and repigmentation. To confirm our hypothesis, we investigated whether elastin fibers can be restored after treatment using phototherapy and/or autologous skin transplantation. Punch biopsies from 14 patients of stable nonsegmental vitiligo vulgaris were collected from nonlesional, lesional, and repigmented skin, and processed to dopa and combined dopa-premelanin reactions. Melanocytes positive to the dopa reaction and melanoblasts/melanocytes positive to the combined dopa-premelanin reaction were surveyed. Moreover, elastin fibers were detected by Victoria blue staining. Numerous melanocytes and melanoblasts were observed in the epidermis of repigmented skin after the treatment. Moreover, in the dermis of repigmented skin, elastin fibers were completely recovered or even upregulated. These results suggest that melanocyte loss in the vitiliginous skin, as well as melanocyte differentiation in repigmented skin, may be at least in part regulated by elastin fibers in the dermis.

[Venous ulcus cruris-Surgical treatment]. / Ulcus cruris venosum ­ chirurgische Therapie.

Venous ulcus cruris is usually a chronic disease and an extreme burden for patients and their families. An analysis based on a random statutory health insurance sample of the AOK Hessen/KV Hessen estimated the number of affected people to be 400,000 in Germany. A venous ulcus cruris is always caused by an underlying chronic venous insufficiency (CVI). A spontaneous healing of this chronic disease without treatment is not to be expected. The conservative treatment includes an adequate compression treatment and exudate management. Surgical treatment is based on three pillars: an open surgical or endovenous approach to resolve the pathological venous reflux, uIcer surgery and in rare cases the various procedures of fascia surgery as well as defect coverage by a combination of negative pressure wound therapy and skin transplantation.

Frostbite injury: an unknown risk when using nitrous oxide as a party drug.

In recent years nitrous oxide has become a popular party drug. Large cylinders filled with nitrous oxide are used to fill balloons for recreational use. We present two patients with severe third-degree cold burns on their thighs after clamping a large cylinder between their legs while filling balloons. During filling, large amounts of nitrous oxide are inhaled, which causes the pain to be numbed. As nitrous oxide is discharged from the cylinder, the cylinder becomes ice cold. Due to direct contact with the icecold cylinder and numbness, third-degree frostbite wounds occur. In both cases presented, the burn wounds had to be debrided and treated with split-thickness skin transplants. Awareness is needed as at first presentation as the burns look superficial, but can rapidly develop into third-degree burn wounds. Close follow-up and aggressive treatment is necessary to prevent infections and to regain a good functional outcome of the affected limb.

Mouse Models for Human Skin Transplantation: A Systematic Review.

Immunodeficient mouse models with human skin xenografts have been developed in the past decades to study different conditions of the skin. Features such as follow-up period and size of the graft are of different relevance depending on the purpose of an investigation. The aim of this study is to analyze the different mouse models grafted with human skin. A systematic review of the literature was performed in line with the PRISMA statement using MEDLINE/PubMed databases from January 1970 to June 2020. Articles describing human skin grafted onto mice were included. Animal models other than mice, skin substitutes, bioengineered skin, postmortem or fetal skin, and duplicated studies were excluded. The mouse strain, origin of human skin, graft dimensions, follow-up of the skin graft, and goals of the study were analyzed. Ninety-one models were included in the final review. Five different applications were found: physiology of the skin (25 models, mean human skin graft size 1.43 cm2 and follow-up 72.92 days), immunology and graft rejection (17 models, mean human skin graft size 1.34 cm2 and follow-up 86 days), carcinogenesis (9 models, mean human skin graft size 1.98 cm2 and follow-up 253 days), skin diseases (25 models, mean human skin graft size 1.55 cm2 and follow-up 86.48 days), and would healing/scars (15 models, mean human skin graft size 2.54 cm2 and follow-up 129 days). The follow-up period was longer in carcinogenesis models (253 ± 233.73 days), and the skin graft size was bigger in wound healing applications (2.54 ± 3.08 cm2). Depending on the research application, different models are suggested. Careful consideration regarding graft size, follow-up, immunosuppression, and costs should be analyzed and compared before choosing any of these mouse models. To our knowledge, this is the first systematic review of mouse models with human skin transplantation.

A novel and efficient method to induce allospecific CD8+ memory T lymphocytes.

The aim of the current study was to establish a simple method for effectively inducing memory T lymphocytes by the intraperitoneal injection of spleen lymphocytes into mice. In total, 75 mice were divided into the following groups: an injection group administered three doses of spleen lymphocytes (1 × 106 , 5 × 106 , and 1 × 107 cells), a transplantation group in which a 0.25-cm2 skin section from C57BL/6 mice was transplanted onto the back of the recipient, and a control group in which an equal volume of phosphate-buffered saline was injected. At 1, 2, or 3 months following transplantation, the following parameters were evaluated: quantity of T lymphocytes, percentage of cluster of differentiation 8+ (CD8+ ) memory T cells, and proliferation index of purified CD8+ memory T cells. No significant differences among groups were detected at 1 month (p > .05). However, the injection group administered 1 × 106 cells exhibited the highest proportion of CD8+ memory T cells among all groups at 2 months, and the proportions of CD8+ T cells were higher in the three injection groups than in the skin transplantation and control groups at 3 months. The proportions of memory T cells were higher in the injection groups administered 5 × 106 or 1 × 107 cells than in the skin transplantation and control groups at 3 months. The newly established method effectively induces memory T lymphocytes via the intraperitoneal injection of spleen lymphocytes in vivo and has potential applications in the field of immunotherapy.

Surgeon's practices and beliefs in Australia and New Zealand regarding the donor site wound for paediatric skin grafts.

AIM: Children's burns care in Australasia is performed by paediatric surgeons and by plastic surgeons. The aim was to determine practices regarding the donor site wound (DSW), and to explore any differences by training scheme or nature of unit (paediatric vs. mixed). METHODS: Online survey of Australasian burns surgeons. RESULTS: Forty surgeons responded. 23/40 paediatric surgeons, 23/40 worked in a stand-alone children's burns unit. All used powered dermatomes. Alginates were the most common DSW dressing. Idealised dressings favour patient factors over cost. Plastic, and mixed-practice, surgeons use a broader range of dermatome settings in children >1 year. Mixed practice surgeons use thicker settings. All surgeons see pain as a common DSW problem. Paediatric surgeons recognise itch as a problem. CONCLUSIONS: While there are differences related to training scheme and the mix of patients being treated, there is a broader commonality of practice.

Treating complex palmar-plantar wounds using a bilaminar 'trapdoor' technique: a case series.

OBJECTIVE: Due to the similarities of glabrous skin, the plantar region is an excellent donor area for covering complex palmar-plantar wounds. However, taking grafts from the plantar area often results in significant morbidity at the donor site or non-integration of the graft due to the greater thickness of the plantar corneal layer. METHOD: This is a prospective case series including patients with burns or wounds who have been treated with a dermal graft using the bilaminar 'trapdoor' technique. This procedure is used to remove a thin graft from the deep plantar dermis after the partial elevation of the first layer including the entire epidermis and superficial part of the dermis. RESULTS: At the donor area in the four patients in this case series, we observed healing at around 10 days, and absence of hypertrophic scar in all patients. There was complete re-epithelialisation between two and three weeks from the periphery to the centre of the deep dermal graft, and from the glandular epithelium transferred with the graft. During the follow-up, patients presented aesthetic and functional features of glabrous and amelanotic skin, with similar resistance to those of the adjacent areas of the wound in the palmar-plantar region. CONCLUSION: This technique has some advantages, such as less surgical time, minimal morbidity in the plantar donor area, easy integration of the grafts, and maintenance of the functional and aesthetic properties of glabrous skin both in the plantar donor area and in the palmar-plantar recipient region. DECLARATION OF INTEREST: The authors have no conflicts of interest to declare.

Historical Evolution of Skin Grafting-A Journey through Time.

Autologous skin grafting was developed more than 3500 years ago. Several approaches and techniques have been discovered and established in burn care since then. Great achievements were made during the 19th and 20th century. Many of these techniques are still part of the surgical burn care. Today, autologous skin grafting is still considered to be the gold standard for burn wound coverage. The present paper gives an overview about the evolution of skin grafting and its usage in burn care nowadays.

A Short History of Skin Grafting in Burns: From the Gold Standard of Autologous Skin Grafting to the Possibilities of Allogeneic Skin Grafting with Immunomodulatory Approaches.

Due to groundbreaking and pioneering developments in the last century, significant improvements in the care of burn patients have been achieved. In addition to the still valid therapeutic standard of autologous split-thickness skin grafting, various commercially available skin substitutes are currently available. Significant progress in the field of tissue engineering has led to the development of promising therapeutic approaches. However, scientific advances in the field of allografting and transplant immunology are of great importance. The achievement of various milestones over the past decades has provided thought-provoking impulses in the field of skin allotransplantation. Thus, biologically viable skin allotransplantation is still not a part of the clinical routine. The purpose of this article is to review the achievements in burn surgery with regards to skin allotransplantation in recent years.

Arteriovenous fistula as adjuvant treatment in arterial revascularization of an at-risk limb.

Acute arterial occlusion remains a major challenge for the vascular surgeon. The therapeutic approach depends mostly upon the severity of the tissue injury and the duration of symptoms. Several techniques are available in the current therapeutic arsenal, however, regardless of the technique chosen, postoperative factors frequently observed, such as poor outflow status, or even low graft flow, can contribute negatively to the outcome of revascularization. We describe a case of acute limb ischemia, in the postoperative period of a femoral-tibial bypass, which was occluded due to outflow limitation and high peripheral vascular resistance. The patient underwent a second tibial revascularization combined with construction of an arteriovenous fistula, followed by forefoot amputation and partial skin graft. An energetic approach to the at-risk limb makes it possible to reduce unfavorable outcomes, such as amputation and death, and accelerates recovery of tissues affected by acute ischemia.