Skin Graft Survival Research Articles

Randomized controlled trial on application of negative pressure materials of polyvinyl alcohol and polyurethane in full-thickness burn wounds after escharotomy

Randomized controlled trial on application of negative pressure materials of polyvinyl alcohol and polyurethane in full-thickness burn wounds after escharotomy

TARGETING CD4+ T CELL METABOLISM PROVIDES AN EFFECTIVE AND AGE-SPECIFIC IMMUNOSUPPRESSION

Targeting T-cell metabolism may provide an effective immunosuppression. We delineated the correlation of aging and T cell metabolism. Moreover, we defined the consequences of metabolic changes in T-cell compartments on alloimmunity and delineated specific and novel immunosuppressive targets on CD-4+ T-cells. We collected naïve CD4+ T cells (splenocytes) of young and old (3 and 18 months) C67BL/6 mice. Following activation with anti-CD3 and anti-CD28 (24 hrs), we evaluated oxidative phosphorylation (OXPHOS) and aerobic glycolysis by oxygen consumption (OCR) and extracellular acidification (ECAR) using a Seahorse XFe96 extracellular flux analyzer. Graft survival, T-cell specificity and a detailed immune profiling were recorded serially. Upon activation in-vitro, a compromised utilization of OXPHOS and glycolysis pathways was observed in old CD4+ T cells (p<0.0001), indicating failure of old CD4+ T cells to exhibit adequate metabolic reprogramming. Further analysis of metabolic pathways revealed a critical role of glutaminolysis in T cell activation. 6-diazo-5-oxo-l-norleucine (DON), an analog of glutamine inhibiting critical enzymes of glutaminolysis resulted into an age-specific reduced activation and proliferative capacities of CD4+T cells. Notably, lower doses of DON inhibited IL-2 production and CFSE-determined proliferation only in old but not young CD4+ T cells (p<0.001). Utilizing a pre-clinical fully mismatched transplantation model, we observed inversed CD4:CD8 ratio in old recipients following DON (1.6mg/kg every other day). Graft survival was prolonged in young recipients, from 7 to 18 days (p< 0.01). Notably, was a drastic and age-specific effect of DON on graft skin graft survival in old recipients to 42 days (n=7, p<0.001). Targeting metabolic pathways was specific to CD4+ T-cells. Adoptively transferring young CD4+ T cells reversed the prolonged survival observed in old recipients. Depletion of CD8+ T cells did not alter transplant outcomes of DON in either young or old recipients. Taken together, we introduce a detailed and age-specific analysis of metabolic pathways in T cells and introduce a novel concept for an optimized immunosuppression in old recipients.

CTLA-4-IG PROLONGS GRAFT SURVIVAL SPECIFICALLY IN YOUNG BUT NOT IN OLD RECIPIENTS

Introduction: The proportion of older transplant recipients has increased dramatically. Age-specific effects of established immunosuppressants are poorly understood. Here, we assessed the impact of CTLA4-Ig, a fusion protein blocking costimulatory signaling between APCs and T cells through CD28. We hypothesized that the immunosuppressive capacity of CTLA4-Ig will depend on an age-specific expression of CD28 on alloreactive T-cells. Methods: Heart and skin grafts from young DBA2/J mice were transplanted into either young or old (2-3 and 18 mths, resp.) allogeneic C57BL/6 recipients treated with CTLA4-Ig or PBS; T-cell frequencies and subsets in addition to cytokine expression were assessed by flow cytometry and ELISA; expression of CD28 was assessed on young and old T-cell subsets. To delineate the age-specific immunosuppressive potential of CTL4-Ig, T-cells were transfected with a lentiviral vector inducing CD28 expression; transfected T-cells were subsequently transferred into young RAG2-/- mice receiving a fully mismatched skin graft. Results: Treatment with CTLA4-Ig prolonged skin graft survival only in young (p<0.01) but not in old recipients (p=0.33). Age-specific immunosuppressive effects of CTLA4-Ig were also confirmed in a SOT model: cardiac allografts in young mice treated with CTLA4-Ig survived indefinitely. In contrast, 80% of old recipients treated with CTLA4-Ig had lost their graft by 100 days. CTLA4-Ig reduced CD4+ central-memory and effector-memory T cells and diminished systemic IFN-γ levels only in young (p<0.05), but not old recipients (p=0.8). These differences correlated with a reduced expression of CD28 on antigen-experienced CD4+ T cells in old mice (p<0.001). Interestingly, Tregs displayed an increased expression of CD28 with age making them more prone to be targeted by CTLA4-Ig. Strikingly, adoptive transfer of old CD4+ T cells that were transfected with a lentiviral vector augmenting the expression of CD28 accelerated the rejection of allogeneic skin grafts in young RAG2-/- recipient mice (p<0.01 vs. controls animals that received adoptively transferred, non-transfected old T cells) demonstrating the cardinal role of CD28 expression on alloreactive CD4+ T cells. Conclusion: Immunosuppressive effects of CTLA4-Ig showed distinct age-dependent effects in both skin and cardiac transplantation linked to a reduced CD28 expression of alloreactive old T-cells in parallel to an augmented CD28 expression on old T-regs. Transfection experiments confirmed the critical role of CD28 in mounting robust alloimmune responses. These findings carry relevant clinical consequences.

Fibrin Glue and Autologous Split-Thickness Skin Graft after Facial Skin Cancer Resection

Objective: To review the key points and limitations of potentiating autologous split-thickness skin graft survival using fibrin glue for the reconstruction of cutaneous defects following oncologic resection of facial tumors. Case Report: A patient who underwent resection of a facial fibrosarcoma and subsequent reconstruction by autologous split-thickness skin graft secured with biologic fibrin glue. Results: There was ninety-percent primary survival of the skin graft at three weeks. Partial necrosis of 10% of the graft surface was successfully managed by debridement and topical application of honey. Conclusion: The time-honored autologous split-thickness skin graft is a useful means of reconstructing cutaneous defects after resection of facial tumors. The application of fibrin glue may avoid the conventional bolster dressing used to stabilize the graft during the early postoperative period.

Distinct roles for major and minor antigen barriers in chimerism-based tolerance under irradiation-free conditions.

Eliminating cytoreductive conditioning from chimerism‐based tolerance protocols would facilitate clinical translation. Here we investigated the impact of major histocompatibility complex (MHC) and minor histocompatibility antigen (MiHA) barriers on mechanisms of tolerance and rejection in this setting. Transient depletion of natural killer (NK) cells at the time of bone marrow (BM) transplantation (BMT) (20 × 106 BALB/c BM cells → C57BL/6 recipients under costimulation blockade [CB] and rapamycin) prevented BM rejection. Despite persistent levels of mixed chimerism, BMT recipients gradually rejected skin grafts from the same donor strain. Extending NK cell depletion did not improve skin graft survival. However, F1 (C57BL/6×BALB/c) donors, which do not elicit NK cell‐mediated rejection, induced durable chimerism and tolerance. In contrast, if F1 donors with BALB/c background only were used (BALB/c×BALB.B), no tolerance was observed. In the absence of MiHA disparities (B10.D2 donors, MHC‐mismatch only), temporal NK cell depletion established stable chimerism and tolerance. Conversely, MHC identical BM (BALB.B donors, MiHA mismatch only) readily engrafted without NK cell depletion but no skin graft tolerance ensued. Therefore, we conclude that under CB and rapamycin, MHC disparities provoke NK cell‐mediated BM rejection in nonirradiated recipients whereas MiHA disparities do not prevent BM engraftment but impede skin graft tolerance in established mixed chimeras.

Meta-analysis of clinical effects of microskin grafting and Meek microskin grafting in repairing extensively deep burn wounds

Objective: To systematically evaluate the clinical effects of microskin grafting and Meek microskin grafting in repairing extensively deep burn wounds using meta-analysis. Methods: Foreign language databases including PubMed and Cochrane Library were searched with the terms of " Meek micrografting, burn" , and Chinese databases including Chinese Journal Full-Text Database, Chinese Biomedical Database, VIP database, and Wanfang Data were searched with the terms in Chinese version of ", Meek," to retrieve the publicly published randomized controlled trials on the microskin grafting and Meek microskin grafting in repairing extensively deep burn wounds from the establishment of each database to March 20, 2019. The outcome indexes included the survival rate of skin graft, primary healing rate, operation time, and surgical treatment cost after the first operation, as well as the wound healing time and length of hospital stay. RevMan 5.3 and Stata 14.0 statistical software were used to conduct a meta-analysis of eligible studies. Results: A total of 821 patients with extensively deep burns were included in 15 studies, including 410 patients in microskin group who received microskin grafting and 411 patients in Meek microskin group who received Meek microskin grafting. The bias risks of the 15 studies included were uncertain. Compared with those of microskin group, the survival rate of skin graft and primary healing rate of patients in Meek microskin group were significantly increased, with relative risks of 0.76 and 0.66 (95% confidence interval=0.66-0.88, 0.50-0.88, P<0.01), the surgical treatment cost was significantly reduced, with a standardized mean difference of 3.19 (95% confidence interval=1.36-5.01, P<0.01), and the operation time, wound healing time, and length of hospital stay were significantly shortened, with standardized mean differences of 6.05, 2.39, and 2.35 (95% confidence interval=3.66-8.44, 1.43-3.35, 2.03-2.68, P<0.01). Subgroup analysis showed that microskin grafting combined with allogenic skin graft might be a heterogeneous source of operation time. Sensitivity analysis showed that the combined effect size was stable in the operation time, surgical treatment cost, and wound healing time. There was no publication bias in the survival rate of skin graft, operation time, wound healing time, and length of hospital stay (P>0.05), while the primary healing rate and surgical treatment cost had publication bias (P<0.01). Conclusions: Compared with microskin grafting, Meek microskin grafting improves the rates of skin graft survival and primary healing, shortens operation time, wound healing time, and length of hospital stay, and reduces the treatment cost in treating extensively deep burn wounds.

B lymphocytes contribute to indirect pathway T cell sensitization via acquisition of extracellular vesicles.

B cells have been implicated in transplant rejection via antibody-mediated mechanisms and more recently by presenting donor antigens to T cells. We have shown in patients with chronic antibody-mediated rejection that B cells control the indirect T cell alloresponses. To understand more about the role of B cells as antigen-presenting cells for CD4+ T cell with indirect allospecificity, B cells were depleted in C57BL/6 mice, using an anti-CD20 antibody, prior to receiving MHC class I-mismatched (Kd ) skin. The absence of B cells at the time of transplantation prolonged skin graft survival. To study the mechanisms behind this observation, T cells with indirect allospecificity were transferred in mice receiving a Kd skin transplant. T cell proliferation was markedly inhibited in the absence of recipient B cells, suggesting that B cells contribute to indirect pathway sensitization. Furthermore, we have shown that a possible way in which B cells present alloantigens is via acquisition of MHC-peptide complexes. Finally, we demonstrate that the addition of B cell depletion to the transfer of regulatory T cells (Tregs) with indirect alloresponse further prolonged skin graft survival. This study supports an important role for B cells in indirect T cell priming and further emphasizes the advantage of combination therapies in prolonging transplant survival.

Engineering Programmed Death Ligand-1/Cytotoxic T-Lymphocyte-Associated Antigen-4 Dual-Targeting Nanovesicles for Immunosuppressive Therapy in Transplantation.

T cell activation by immune allorecognition is a major contributing factor toward the triggering of organ rejection. Immunosuppressive drugs have to be taken after organ transplantation, but long-term use of these drugs increases the risks of infection and other serious disorders. Here, we showed dysregulation of programmed cell death-ligand 1/programmed cell death 1 (PD-L1/PD-1) and cytotoxic T-lymphocyte-associated protein 4/cluster of differentiation 80 (CTLA-4/CD80) in the spleen of two organ transplantation models. Using a bioengineering approach, cellular exosome-like nanovesicles (NVs) displaying PD-L1/CTLA-4 dual-targeting cargos were designed, and their specificity to bind their ligands PD-1 and CD80 on T cell and dendritic cell surfaces was confirmed. These NVs consequently enhanced PD-L1/PD-1 and CTLA-4/CD80 immune inhibitory pathways, two key immune checkpoints to co-inhibit T cell activation and maintain peripheral tolerance. It was also confirmed that PD-L1/CTLA-4 NVs led to the reduction of T cell activation and proliferation in vitro and in vivo. Finally, it was demonstrated that PD-L1/CTLA-4 NVs reduced density of CD8+ T cells and cytokine production, enriched regulatory T cells, and prolonged the survival of mouse skin and heart grafts. Taken together, these data supported the idea that PD-L1/CTLA-4 dual-targeting NVs exert immune inhibitory effects and may be used as a prospective immunosuppressant in organ transplantation.

The surgical treatment of male perineum Paget's disease

Objective: To evaluatethe clinical efficacy and complications of skin graft and flap plastic technique covered the defect in perineal Paget's disease postoperatively. Methods: The study comprised 6 patients diagnosed with perineal Paget's disease at Beijing Chao-Yang Hospital from June 2017 to July 2019, with all available clinical data reviewed. The defects after resection of lesions were reconstructed with skin graft, advancement skin flap during the operation, respectively. The operation time, the skin graft or flap survival situation, intraoperative and postoperative complications were recorded. Results: Of all 6 patients, Ray stage A1consisted of 1 case, A2 5 cases. The age was (68±9) years, the hospitalization time was (14.8±8.1) days, the BMI was (25.6±3.7) kg/m(2), the operation time was (132.0±80.7) min, and the average blood loss was (18.3±11.7) ml. Five cases was with Paget's disease, and 1 case with skin adenocarcinoma with Paget's disease were diagnosed by pathology. The defects of 4 cases and 2 cases after removal of the tumor were reconstructed with scrotal advancement skin flap and skin graft, respectively. The skin graft and flap survived well during afollow-up of (15.3±8.1) months.There has been no local recurrence. The foreskin edema and wound infection were noted in 4 cases and 1 case, respectively. There was no other related complications. Conclusion: Perineal Paget's disease can be managed by resection and immediate reconstruction with skin graft or flap according to the size and location of the defect, and the clinical efficacy is distinct.

Severe Skin Ulcer on the Hand Caused by Hemodialysis Shunt-related Venous Hypertension That Required a Skin Graft.

Summary:In dialysis patients, peripheral venous hypertension–induced hand ulcers are rare. We report a case in which a severe hand ulcer was treated with skin grafting after shunt ligation. The patient was a 60-year-old woman who been undergoing dialysis for 13 years. Twelve years ago, a shunt was created in her right wrist via a side-to-side anastomosis. Swelling and congestion occurred in the right hand, and skin ulcers developed on the dorsal proximal portions of the index, middle, ring, and little fingers. No central vein obstruction was apparent. The right wrist shunt was explored, and the distal vein was ligated. A new shunt was created at the right elbow, but the proximal end of the vein that was used for the wrist shunt had to be used, resulting in complete cephalic vein occlusion from the wrist to the elbow. The swelling extended to the entire forearm. Four weeks after the wrist and elbow shunts were ligated, conservative treatment had resulted in granulation tissue formation in the ulcers. Debridement and full-thickness skin grafting from the abdomen were performed. Overall, skin graft survival was 75%. In conclusion, in this patient, side-to-end anastomosis of the proximal vein might be appropriate for shunt creation. When venous hypertension is suspected, ensuring an appropriate alternative shunt, promptly detecting the cause of the problem, and appropriate treatment are important. Venous hypertension must be completely resolved before surgery for ulcers.

Comparison of split skin thickness graft survival in diabetic and non-diabetic ulcer

Background: Split skin grafting is widely used surgical procedure for the treatment of ulcers. Graft survival depends on number of factors like vascularity, wound infection etc, diabetes is associated with endothelial dysfunction, neuropathy, wound infection which collectively affect the graft survival. Objective of this study was to compare the amount of graft uptake, the post-operative complications and survival of split thickness skin graft in diabetic and non-diabetic ulcer.Methods: In our prospective comparative study total 112 patients with ulcer were included of which 56 were diabetic and 56 were non-diabetic. All of t7hem underwent split skin grafting as part of their wound management. Comparison was made between two groups in terms of amount of graft uptake, post-operative wound infection, revisional surgery, donor site infection.Results: Compared with non-diabetics, diabetics have significantly less graft uptake (p&lt;0.001). out of 56 patients in diabetic group 4 (66.7%) underwent revisional surgery, out of 56 patients in non-diabetic group 2 (33.3) patients underwent revisional surgery (p value is &lt;0.68) which is statistically insignificant. 3 (60%) out of 56 in diabetic group developed post-operative graft infection, 2 (40%) out of 56 in non-diabetic group developed graft infection (p=1, not significant). One patient in the study developed donor site infection. Among 112 cases, only 1 case had donor site infection with diabetic.Conclusions: Diabetes is associated with poor graft uptake and post-operative complication rates in patients undergoing split skin grafting.

Clinical effect of bi-layered artificial dermis and autologous skin graft in repairing bone and/or tendon exposed wounds

Objective: To explore the clinical effect of bi-layered artificial dermis combined with autologous skin graft in the repair of wounds with exposed bone and/or tendon. Methods: The medical records of 25 patients (aged 3 to 79 years, including 21 males and 4 females) with bone and/or tendon exposed wounds caused by various reasons, admitted to Nanfang Hospital of Southern Medical University from May 2014 to December 2018 were analyzed retrospectively. Of the 25 patients, 7 patients had exposed bone only, 13 patients had exposed tendon only, and 5 patients had exposure of both bone and tendon. The total wound area was 78.0 (53.4, 103.2) cm(2). The widths of bone exposure and tendon exposure were 3.2 (3.0, 3.6) cm and 2.0 (1.7, 2.4) cm, respectively. All wounds were implanted with bi-layered artificial dermis in the first stage after thorough wound debridement. After 2 to 3 weeks of vascularization of artificial dermis, autologous thin-to-medium-thickness skins or split-thickness skins were grafted to repair the wounds in the second stage. The vascularization of artificial dermis and its time, whether or not producing hematoma, the skin graft survival rate on day 7 post autologous skin grafting, whether or not repeating skin grafting, and the time of complete wound healing were observed and recorded. The patients were further followed up and observed for 3 or more months after discharge. Results: The vascularization of artificial dermis was achieved in 24 patients after the first transplantation with vascularization time being 11-21 (16±4) days. No hematoma was observed in the transplanted artificial dermis. Failed vascularization of grafted artificial dermis was observed in one patient who was later treated with negative pressure drainage and skin grafting alone, and was discharged with wound healing. The skin graft survival rate on day 7 post autologous skin grafting was 92.2%-100.0% ( (99.3±1.3)%), with the remaining wound areas recovered later by themselves or healed by dressing changes without repeated skin grafting. The complete wound healing time was 7-19 (11.9±2.8) days after autologous skin grafting. The patients were followed up for 3 to 60 months after discharge. Except for the pigmentation in skin graft area, the skin grafts survived well, being soft in texture and with no repeated ulceration, obvious hypertrophic scar, or contracture deformity. Conclusions: Artificial dermis combined with autologous skin grafting can effectively repair wounds with bone and/or tendon exposure, providing a repair strategy for this type of wounds.

Effects of anterolateral thigh free flap with fascia lata in repairing dura mater defect after resection of head squamous cell carcinoma

Objective: To evaluate the clinical effects of anterolateral thigh free flap with fascia lata in the repair of dura mater defect after resection of head squamous cell carcinoma. Methods: From June 2016 to June 2018, Xijing Hospital of Air Force Medical University applied the free transplantation of anterolateral thigh flap with fascia lata to repair the dura mater defect of 12 patients with head squamous cell carcinoma, including 9 males and 3 females, aged from 35 to 74 years. The size of scalp soft tissue defects in patients after carcinoma resection ranged from 12 cm×10 cm to 24 cm×21 cm, and the size of dura mater defect of patients ranged from 7 cm×6 cm to 16 cm×14 cm. The size of flap of patients ranged from 14 cm×12 cm to 27 cm×24 cm, and the size of fascia lata ranged from 8 cm×7 cm to 17 cm×15 cm. The superficial temporal artery and middle temporal vein were connected by end to end anastomosis with the first musculocutaneous perforating branch of the descending branch of lateral femoral artery and its accompanying vein. The flap donor area was transplanted with autologous split-thickness skin graft from trunk and fixed with packing. Postoperative survival of flaps and skin grafts was observed. The patients were followed up regularly. The cranial magnetic resonance imaging was performed to observe the recurrence of intracranial tumors and dural integrity, shape of the flap and whether the donor site region was left with significant dysfunction were observed. Results: All the flaps and skin grafts survived well in 12 patients after surgery. Ten patients had primary healing at the edge of the flap suture; 2 patients had local sinus tract formation at the suture site of flap, with a small amount of cerebrospinal fluid leakage, and were recovered after outpatient dressing change. The patients were followed up for 10 to 36 months, and 3 patients with tumors involving in the dura mater sagittal sinus region had postoperative intracranial tumor recurrence. The tumor was resected again. All the patients had good dural integrity. The flaps of all patients were in good shape, and no obvious dysfunction remained in the flap donor site. Conclusions: Free transplantation of anterolateral thigh flap with fascia lata is an effective and reliable method to repair the dura mater defect following head squamous cell carcinoma resection. It can repair the scalp and dura mater defects caused by the invasion of squamous cell carcinoma and provide possibilities for skull reconstruction.

Effects and mechanism of interleukin-17-modified mouse bone marrow mesenchymal stem cells on rejection reaction of allogeneic skin transplantation in mice

Effects and mechanism of interleukin-17-modified mouse bone marrow mesenchymal stem cells on rejection reaction of allogeneic skin transplantation in mice

Exploration on the method of aesthetic repair of the donor sites of flaps

Objective: To explore the excellent methods for aesthetic repair of the donor sites of flaps. Methods: From January 2013 to March 2018, 120 patients (94 males and 26 females, aged from 3 to 60 years) were admitted to the Department of Burns of Beijing Jishuitan Hospital. Wounds areas after debridement or removing scar were ranged from 8.0 cm×3.5 cm to 24.0 cm×18.0 cm. Twenty patients with facial and neck scar were repaired with expanded flaps, including 4 scalp flaps, 8 supraclavicular flaps, 4 deltoid flaps, and 4 trapezius myocutaneous flaps. The flaps in ideal donor sites were selected to repair the wounds in 40 patients, including 20 cases of hand wounds or scars repaired with inguinal flaps, 10 children of foot skin defects or scars repaired with cross inguinal skin flap, 10 cases of knee joint wounds repaired with medial or lateral thigh flaps. The optimal flap design was used to repair wounds in 50 patients. Among the patients, wounds of 36 patients were repaired with relaying flaps, including donor sites of free anterolateral thigh flaps of 8 patients repaired with anteromedial thigh perforator flaps and donor sites of free anterolateral thigh flaps of 8 patients repaired with ilioinguinal flaps or superficial abdominal artery flaps, and donor sites of flaps of 20 patients repaired with peroneal perforator relaying flaps. Besides, wounds of 9 patients were repaired with free lobulated anterolateral thigh flaps, and wounds of 5 patients were repaired with modified V-Y propelling latissimus dorsi myocutaneous flaps. The donor sites of flaps were repaired with allogenic acellular dermal matrix combined with autologous split-thickness skin grafts in 10 cases. The areas of the flaps or myocutaneous flaps were ranged from 6.0 cm×4.0 cm to 30.0 cm×20.0 cm. The survival of flap, myocutaneous flap, or skin graft and the repair of donor site after operation and during follow-up were observed. Results: Blood flow obstacle at 0.5 cm to the distal margin of the flap occurred in 1 patient repaired with expanded flap, which were healed after dressing change. Blood supply disorder occurred at the tip of the anteromedial thigh perforator flap of 1 patient repaired by optimal flap design, which were healed completely after second debridement and restitching. The other flaps or myocutaneous flaps survived well. The allogenic acellular dermal matrix and the autologous split-thickness skin graft survived with good color and texture. During follow-up of 3 months to 4 years, the donor sites of flaps had good appearance, only with linear scar and the function recovered well. The donor sites of skin grafts had no scar hyperplasia, only with scattered pigmentation. Conclusions: According to the characteristics of donor sites of flaps, individualized and reasonable design before the operation such as pre-expanding of the flaps, selecting the ideal donor sites, optimization of the flap design or allogenic acellular dermal matrix combined with autologous split-thickness skin graft to repair donor sites of flaps can minimize the damage for function and appearance of donor sites of flaps and achieve aesthetic effects of donor sites of flaps.

Platelet-Rich Plasma for Skin Graft Storage: An Experimental Study Using Rabbit Ears.

Storage of surplus grafts for later use is one of the standard procedures used in plastic surgery. For the delayed use of skin grafts, various methods and media have been investigated for short-term storage. This study aimed to investigate the effect of platelet-rich plasma (PRP) skin graft storage on the survival of skin grafts obtained from rabbit ears. Twelve rabbits were used in this study. A total of 12 skin grafts measuring 1 × 1 cm were obtained from the inner surfaces of the rabbits' ears. The grafts were stored at +4°C in saline, Hartmann's, and PRP media. On days 3, 7, 10, and 14, the grafts were implanted into the ears in areas measuring 1 × 1 cm where the skin, cartilage, and perichondria were excised. After the implantation of the grafts, the survival rates were evaluated by measuring the graft areas on day 0, day 10, and day 30. The graft survival rate decreased as the storage period increased in all 3 of the media. The decrease in survival rate was higher in the grafts that were stored in the Hartmann's media in comparison with the saline and PRP media, and the difference was statistically significant. The decrease in graft survival was similar between the storage in saline and PRP media; however, the differences were statistically insignificant. Although in vitro criteria are important for evaluating graft survival, in vivo studies showing the graft take rate in the recipient area are required. When the in vivo criteria are evaluated, the use of PRP is not superior to the use of saline for graft storage. However, additional studies are required to evaluate the effects of PRP media on graft quality.

Cellular Therapy with Donor Mesenchymal Stem Cells Combined with Co-Stimulation Blockade Prolongs Solid Organ Allograft Survival.

<h3>Introduction</h3> Co-stimulation blockade (CoB) has emerged as a promising immunosuppression strategy and potential alternative to calcineurin inhibitors in solid organ transplantation. Despite recent advancements, CoB based regimens are hampered by increased rates of acute cellular rejection. Bone marrow derived mesenchymal stem cells (BM-MSCs) offer a clinically relevant cellular therapy to suppress T cell alloreactivity and prolong allograft survival. <h3>Objectives</h3> Here we studied the effects of combined donor BM-MSCs and CoB on allograft survival in both murine and non-human primate (NHP) models of transplantation. <h3>Methods</h3> BM-MSCs were cultured and serially passaged in an alpha Minimum Essential Medium based media and subsequently characterized by flow cytometry. A mouse model of MHC mismatched skin transplantation (Balb/C C57BL/6) was used to assess the effect of donor splenocytes vs. BM-MSCs on allograft survival. Next, we investigated whether donor BM-MSCs could prolong renal allograft survival in a fully MHC mismatched NHP model. Mixed lymphocyte reactions (MLRs) were also performed to assess the impact of NHP BM-MSCs on T cell responses <i>in vitro</i>. <h3>Results</h3> Balb/C BM-MSCs administered intravenously on days 1,3, and 5 post-transplant (10⁵ cells per infusion) significantly prolonged skin graft survival compared to identical administration of Balb/C splenocytes in the setting of CoB treatment (CTLA-4Ig + anti-CD154) (MST 40 days vs. 21 days, p = 0.04*). In NHP, BM-MSCs were characterized by expression of CD3-/CD11b-/CD16-/CD20-/CD34-/HLA-DR-/CD44+/CD73+/CD90+/CD105+. Repeated infusions of donor BM-MSCs (2 × 10⁶ cells/kg per infusion) combined with CoB (anti-CD28 + anti-CD154) (n=4) prolonged renal allograft survival compared to CoB alone (n = 3) (MST 228.5 days vs. 41 days, p = 0.09). <i>In vitro</i>, NHP BM-MSCs suppressed allo-stimulated T cell proliferation and cytokine effector function in a contact independent fashion. <h3>Conclusion</h3> Donor BM-MSCs prolong allograft survival in both murine and NHP models of transplantation when combined with CoB treatment. These data suggest BM-MSCs are a promising cellular therapy to suppress co-stimulation resistant T cell alloreactivity and prevent cellular rejection in clinical solid organ transplantation.

Induction of immune tolerance towards allogeneic cells using fetal directed placental injection in a murine model

Objective: In utero exposure to foreign antigens prior to the development of the immune system induces immune tolerance. We aimed to induce immune tolerance towards allogeneic cells by early gestational transplacental injection under ultrasound guidance in a murine model. Methods: Bone marrow cells from C57BL/6-Green Fluorescence Protein transgenic mice were transplanted into the placenta of Balb/c fetal mice at 11-day of gestation under ultrasound guidance. Each fetus was injected with 2 × 105 cells/2.5 μl. After birth, we evaluated the immune response against allogeneic donor cells. Results: The birth survival rate was 21.2% for allogeneic mice. Survival of the donor skin graft was 75% and successful in mice injected with fetal transplacental cells, whereas the transplanted allogeneic skin was all rejected within 4 weeks in control naive mice (p=0.007). Cytotoxic immune reactivity against the allogeneic cells was suppressed according to the ELISPOT assay (p=0.002). Conclusion: We showed that early transplacental allogeneic cell injection can induce donor-specific tolerance sufficient to allow tissue graft.

Split-thickness scalp and allogenic acellular dermal matrix in repairing deep wounds of hands in patients with extremely extensive burns

Objective: To explore the clinical effects of split-thickness scalp and allogenic acellular dermal matrix (ADM) in repairing deep wounds of hands in patients with extremely extensive burns. Methods: Six patients with extremely extensive burns complicated by deep burn in hands were admitted to our department from December 2014 to December 2017, including 4 males and 2 females, aged 21 to 58 years. Their total burn areas were from 85% to 95% total body surface area (TBSA), and the sum of deep-partial thickness and full-thickness wounds was larger than 50% TBSA. Under general anesthesia, deep wounds of 10 dorsal hands were repaired by combined transplantation of split-thickness scalp and allogenic ADM in 4 to 6 weeks after injury. The skin grafting range was beyond the metacarpophalangeal joint, including partial dorsal digital deep wounds. Survival of skin grafts on dorsal hands, follow-up of hand shape and functional recovery were observed and recorded. Results: Six patients were successfully treated. There was no infection on the dorsal deep wounds of 10 hands after surgery, and the grafts survived well. During follow-up of 1 to 2 years after operation, there were no recurrent tension blisters or dorsal extension deformity of the metacarpophalangeal joints in 10 hands, the shape and function of hands recovered well, and hand Carroll scores were from 90 to 99 points, with functional levels of Ⅴ and Ⅵ. Conclusions: The combined transplantation of split-thickness scalp and allogenic ADM is a good method for repairing deep hand wounds in patients with extremely extensive burns, which can alleviate the cicatrix hyperplasia and contracture of healed hand wounds, and improve the shape and function of hands.

Management of Fournier gangrene in perineal region by negative-pressure wound therapy combined with delayed repair

Objective: To explore the effects of negative pressure wound therapy (NPWT) combined with delayed repair on Fournier gangrene in perineal region. Methods: During July 2010 to September 2018, 16 patients with Fournier gangrene in perineal region were admitted to our center, with 13 males and 3 females, aged 30 to 76 years. In the first stage, the necrotic tissue of the wound was completely removed according to the scope of the lesion, and NPWT was applied. After the operation, general anti-infection and nutritional support were performed. In the second stage, the local flaps, free flaps, or skin grafts were chosen to repair the wounds according to the specific condition of wounds. The average length of stay and pathological diagnosis were recorded, and the survival and follow-up of skin grafts and flaps were recorded. Results: All the 16 patients were cured and discharged, with an average of 29.6 days in hospital. The pathological diagnosis of biopsies were necrotizing inflammation. The wound of 1 patient was healed directly after only NPWT, the skin grafts of 5 patients, local flaps of 9 patients, and anterolateral thigh island flap of 1 patient who had NPWT combined with delayed repair survived well. Sixteen patients were followed up for 1 to 2 years after discharge, and no recurrence of Fournier gangrene was found. Among them, 5 patients with wounds involved perineum and scrotum had good appearance and function of scrotum and mons pubis. Conclusions: NPWT combined with delayed plastic repair have great effects on Fournier gangrene.