Secondary Skin Grafting Research Articles

Bioimaging of alloantigen-stimulated regulatory T cells in rat vascularized composite allotransplantation.

BackgroundTipping the balance toward regulatory T cells (Tregs) through adoptive cell therapy has shown promise to induce transplantation tolerance. Although such strategy has been explored in many mice organ transplantation studies, less knowledge was available in rat systems. Furthermore, the behaviors of the transferred cells have not been well studied in real-time fashion.MethodsTregs from naïve LEW rats were purified in two steps with the autoMACS system. Immunosuppression potential of these cells was examined with mixed lymphocyte reaction. Following stimulation by the alloantigen in vitro, the purified Tregs were infused into the recipients of vascularized composite allotransplantation (VCA). Secondary allogeneic skin grafting challenge was performed on the recipients with long-term survived VCA. Live optical imaging was performed to track luciferase-expressing Tregs following infusion to the VCA recipients. Expression of relevant molecules was studied by flow cytometry or quantitative RT-PCR.ResultsRat Tregs were enriched following two-step cell sorting and showed immunosuppressive capacity. Upon infusion into the VCA recipients that have been treated with antilymphocyte serum and short-term Cyclosporin A, the antigen-stimulated Tregs significantly prolonged VCA survival and induced donor-specific tolerance. Tracking of the infused bioluminescent Tregs showed their specific homing to lymph nodes, and then to the VCAs. Following secondary skin grafting, Tregs specifically gathered at the donor-derived skin that was not rejected by the recipient. The in vivo migratory pattern coincided with the altered expression of cell surface molecules of CD62L, CD103, CD134, and CD278, following donor-antigen stimulation. Elevated expression of CCR4 and CCL22 in allograft may also participate in recruiting Tregs for maintenance of VCA survival and promoting donor-specific tolerance.ConclusionSorted Tregs induced donor-specific tolerance to VCA in rats. Live cell tracking demonstrated that activated CD4+CD25+FoxP3+ Tregs targeted primarily to the lymph nodes and VCA. The Tregs migrated to the secondary grafted donor skin and contributed to the maintenance of donor-specific tolerance. These behaviors were associated with phenotypic changes induced by donor antigen stimulation. Increased expression of CCR4 and CCL22 in VCA skin may also be relevant.

Clinical application of anterolateral thigh flap in wound around the knee with descending genicular artery as the recipient vessel

Objective To explore the clinical application of anterolateral thigh flap transplantation in repairing wound around the knee with descending genicular artery as the recipient vessel, when anterior or posterior tibial vessel could not be utilized. Methods From January, 2015 to May, 2017, free anterolateral thigh flaps obtained from anastomosis of descending genicular artery and great saphenous vein were transplanted to repair the skin soft tissue defect around the knee combined with tendon and bone exposure in 7 patients, after preoperative color Doppler sonography ultrasound (CDU) for precise positioning. There were 4 males and 3 females, with the flap area ranging from 18.0 cm×8.0 cm-38.0 cm×8.0 cm. All of the donor sites were sutured directly. Postoperative followed-up was done termly. Results All the patients were followed-up for 6 to 14 months, with an average of 8.9 months. Typically, 2 cases had large defect areas, with distal flap necrosis of 6.0 cm and 4.0 cm, respectively, which were resected and achieved secondary skin graft healing on the residual surface. Additionally, 4 cases had completely survived flaps and achieved secondary skin graft healing on the residual surface. The remaining 1 case had completely survived flap, but the distal flap near the anteromedial tibia developed bone exposure as a result of the complicated osteomyelitis. As a result, the patient received gastrocnemius myocutaneous flap to repair the wound. Conclusion Anterolateral thigh flap transplantation in repairing skin soft tissue defect wound around the knee, with descending genicular artery as the recipient vessel, can achieve satisfactory clinical efficacy, which can serve as one choice for flap repair in wound around the knee. Key words: Anterolateral thigh flap; Descending genicular artery; Knee joint; Transplantation

Protocol of diagnosis and treatment for scalp avulsion injury

Objective To search for a treatment approach for scalp avulsion injury based on the clinical experiences and review of literature. Methods Twenty-six consecutive scalp avulsion cases were involved in the study: 15 cases were complete scalp avulsion (5 including forehead skin) and 11 cases were partial scalp avulsion. Cranial bones exposure occurred in 16 cases, 11 of which had a size over 4×4 cm2. The treatment methods were various: 11 cases with microsurgical replantation, 9 cases with skin grafting, 4 cases with secondary skin grafting followed by multiple drilling of the calvarium, 1 case with local flap, and 1 case with free flap. According to the clinical cases and literature reviews, authors tried to search for an optimal protocol. Results Patients with microsurgical replantation achieved the best recovery including hair growth. In case of not qualified or fail to microsurgical replantation, skin graft could be considered as an alterative step, whereas the result of it was no hair growth and usually scar healing. In summary, 14 different clinical conditions followed with 10 surgical techniques were concluded in a route chart. Conclusions To achieve the optimal outcomes of scalp avulsion injury, proper techniques should be chosen according to the treatment protocols. Key words: Scalp avulsion injury; Microsurgical replantation; Skin graft

Scalp and Forehead Reconstruction.

Reconstructing the scalp and forehead is a challenging endeavor frequently undertaken by facial plastic and reconstructive surgeons. There are many anatomical factors to be considered in this area, including multiple neurovascular structure present that should be identified and preserved. Hair morphology and physiology should be considered, and trichophytic techniques should be incorporated into incision planning and closure. The reconstructive ladder must be used when considering options in reconstructing scalps and forehead defects. This article reviews reconstructive options including secondary intention, primary closure, skin grafting, allografts, tissue expanders, and local, regional, and free tissue transfers, among others in the surgical management of forehead and scalp defects. The reconstructive surgeon should be familiar with these techniques and be able to use them when indicated, based on the size, shape, and location of defects.

Combined effects of artificial dermis and vascular endothelial growth factor concentration gradient on wound healing in diabetic porcine model

Wounds in patients with diabetes mellitus are one of the most prevalent impaired wounds in the world. Vascular endothelial growth factor (VEGF) is one of the most important proangiogenic mediators. Artificial dermal (AD) such as Pelnac® has been shown, in humans and animal models, a great therapeutic potential in full-thickness skin wounds. We attempt to promote the wound healing in diabetic porcine models through combined use of AD and constant concentration of VEGF or VEGF concentration gradient. We created full-thickness excisional wounds in diabetic animal models. Analyzed the healing process through images, histology and immunohistochemistry. Results show that the combination of AD and concentration gradient of VEGF could provide an appropriate angiogenesis, improve granulation formation, increase epithelization and maintain the VEGF levels of the wound bed. Eventually accelerate the direct healing of diabetic wounds or make good preparation for secondary skin graft.

T cells expressing chimeric antigen receptor promote immune tolerance.

Cellular therapies based on permanent genetic modification of conventional T cells have emerged as a promising strategy for cancer. However, it remains unknown if modification of T cell subsets, such as Tregs, could be useful in other settings, such as allograft transplantation. Here, we use a modular system based on a chimeric antigen receptor (CAR) that binds covalently modified mAbs to control Treg activation in vivo. Transient expression of this mAb-directed CAR (mAbCAR) in Tregs permitted Treg targeting to specific tissue sites and mitigated allograft responses, such as graft-versus-host disease. mAbCAR Tregs targeted to MHC class I proteins on allografts prolonged islet allograft survival and also prolonged the survival of secondary skin grafts specifically matched to the original islet allograft. Thus, transient genetic modification to produce mAbCAR T cells led to durable immune modulation, suggesting therapeutic targeting strategies for controlling alloreactivity in settings such as organ or tissue transplantation.

Control of alloreactivity using transient expression of a monoclonal antibody directed chimeric antigen receptor in conventional and regulatory T cells

Abstract The genetic modification of T cells offers many promising cellular therapies, but little known about how the transient targeting of T cell or T cell subsets such as CD4+CD25+FoxP3+ regulatory cells (Treg) could be used to control alloreactivity. We used the expression of a chimeric antigen receptor that recognizes labeled therapeutic monoclonal antibodies, to control T cell activation in vivo. By specifying the location of activation of donor T cells during hematopoietic cell, we modulated graft-versus-host disease and anti-leukemia effects. We also controlled the activation of Treg cells which remain immunoregulatory. When recipient Treg are targeted to activate in response to MHC Class I mismatch, we observed significantly prolonged allogeneic islet graft survival in an antigen-specific manner, as secondary skin grafts were specifically protected against rejection. The transient genetic modification of T and Treg can have lasting effects on the immune system and could be used therapeutically to regulate alloreactivity.

Reconstruction of the conchal bowl

The auricular concha is derived from the cleft ectodermal tissue of the first branchial groove. Deformities of the concha may result from congenital malformations, traumatic injury, or oncological resection. Although multiple studies have demonstrated the negative psychosocial effect of auricular deformity, various surgical techniques have been developed to reconstruct the ear and obtain satisfactory cosmetic outcomes. Reconstruction of the concha will largely depend on depth and size of the overall defect with options largely varying among secondary intention, skin grafting, and soft tissue flaps.

Necrotizing soft tissue infections: a clinical profile

Background: Necrotizing soft tissue infections (NSTIs) are a rapidly progressing fatal disorder and the prognosis of which depends on early diagnosis and management.Methods: This was a prospective observational study carried out in the surgical department of Jubilee Mission Medical College and Research Institute from August 2010 to August 2012 in 75 patients presented with NSTIs having extensive tissue necrosis. The following parameters were analyzed: demographics, infection site, laboratory findings, isolated microorganisms, antibiotics used, total hospital stays, predisposing factors, associated comorbidities and secondary management performed.Results: 75 patients with NSTIs were enrolled in this study. Youngest in this series is 3 years and oldest patient was 89 years old, with most-commonest age group being 41 to 60 years. Average age of patients is 55 years. Male: Female is in the ratio 9:1. Diabetes mellitus was seen as the common underlying disease in 20 patients. Lower limb (85%) was the most commonly affected site. Most of the patients (69) arrived with a delay in intervention of more than 3 days. Average delay in intervention from onset of symptoms of patients is 10 days. After analyzing, 26 patients were categorized in to Group 1 (survival) and the remaining 49 were into Group 2 (morbidity/mortality). In death patients Creatinine is very high 2.3 mg/dl and it is least in non-morbidity. In cases with morbidity it varies from 1.27-1.87 mg/dl. The incidence ratio of monomicrobial: polymicrobial: sterile microbial culture was 2:2:1. E. coli is the highest seen organism in monomicrobial and polymicrobial cases. Klebsiella is mostly seen in poly organism. Staphylococcus aureus is seen reasonably in polymicrobial and monomicrobial cases. Meropenem and imipenen are instituted as the most sensitive drugs with sensitivity above 90%. Most patients where managed by healing with secondary intention or split skin grafting. The average number of debridement is 1.2. The average duration of hospital stay is 26 days. 12 patients developed septicemia with multi organ dysfunction syndrome (MODS) as complications. Of these three patients survived. Mortality rate was 12%.Conclusions: NSTI is a lethal disease and early diagnosis based on high index of clinical suspicion and prompt and aggressive surgical, antibiotic and supportive therapy is essential for the better prognosis and early recovery of the disease.

Fillet flap method of ear keloid repair and its cosmetic outcome: our experience

Background: Formation of keloid after cosmetic or traditional ear piercing is a very distressing condition for the patient. Ear lobe keloid has been treated with excision followed by primary suture, healing by secondary intention, skin graft or local flap. Fillet flap technique has come up with good cosmetic result, late combined with other medications.Methods: 20 patients were treated by fillet flap technique. Included in the study were huge, sessile, recurrent keloids. Pedunculated and small (<1 cm) keloids were excluded.Results: All cases, except one flap survived completely with good primary healing. All patients were women and developed their lesions after cosmetic earlobe piercing. The lesions were unilateral in 16 (80%) patients and bilateral in four (20%) patients. After 1 year, major response was observed in fifteen cases (75%) and moderate response in four cases (20%); one case had a relapse 10 months after the surgery.Conclusions: Many methods of coverage of defect after surgical excision have been described but each has its own disadvantages. So, fillet flap technique covers the defect and gives very good cosmetic outcome.Fillet flap method of ear keloid repair and its cosmetic outcome: our experience

Coverage of Tendon Exposure after Radial Forearm Free Flap by the Dorsoulnar Artery Perforator Flap.

Objective This study was designed to assess the effectiveness of an alternative technique using a perforator flap to manage secondary tendon exposure after a radial forearm free flap in head and neck oncologic surgery. Study Design Prospective cohort study. Setting Plastic Reconstructive Surgery Unit, Nice University Hospital, Pasteur 2 Hospital, France. Subjects and Methods Despite its numerous advantages, the radial forearm free flap is associated with significant donor site morbidity and the risk of secondary tendon exposure. Conventional skin grafts for secondary tendon exposure can lead to diminished wrist range of motion and grip strength, with residual pain and cold intolerance. Between 2012 and 2015, we prospectively studied 20 patients with secondary tendon exposure after a forearm radial free flap for head and neck reconstruction. Two techniques of secondary coverage were compared: a reference technique with a secondary full skin graft (10 patients) and a dorsoulnar artery perforator (DUAP) flap (10 patients). Results Maximum wrist extension (100%) was observed for the DUAP group compared with only 87% for the skin graft (SG) group ( P = .001). An improvement in grip strength (+14 kg) ( P = .028) and a decrease in pain or cold intolerance ( P = .002) were also observed in the DUAP group, in addition to a better aesthetic appearance. Conclusion The perforator flap procedure is an interesting tool in reconstructive surgery. The DUAP flap is a reliable, useful flap for secondary tendon exposure coverage after a radial forearm free flap. Level of Evidence III (case-control analytic studies of 1 center).

Adipose-derived aldehyde dehydrogenase-expressing cells promote dermal regenerative potential with collagen-glycosaminoglycan scaffold.

Aldehyde dehydrogenase (ALDH) is an enzyme that plays an important role in retinoid metabolism and highly expressed in stem cells. This study isolated ALDH-expressing cells from subcutaneous adipose tissue and investigated their potential to enhance healing in a full-thickness skin wound in rats by co-implanting them with collagen-glycosaminoglycan (c-GAG) scaffolds. ALDH-positive cells were isolated by a fluorescence-activated cell sorting technique from Lewis rat's stromal-vascular-fraction (SVF) and transplanted with c-GAG scaffolds in a rat full-thickness skin wound model. At 7 days after surgery, the microscopic appearance of c-GAG scaffolds seeded with ALDH-positive was compared with those of uncultured-SVF, and cultured-SVF adipose-derived stromal cells (ASCs). The thickness of cellular ingrowth in the ASC group (630 ± 180 μm) was significantly thicker than that in the control (390 ± 120 μm) or SVF (380 ± 140 μm) groups, but non-significantly thicker than that in the ALDH-positive group (570 ± 220 μm). The thickness of regenerated collagen layer was significantly thicker in the ALDH-positive group (160 ± 110 μm) than in the ASCs (81 ± 41 μm), the control (65 ± 24 μm), or SVF (64 ± 34 μm) groups. Immunofluorescent staining with CD31 proved that transplanted ALDH-positive cells differentiated into vascular endothelial cells in c-GAG scaffolds. Combined transplantation with c-GAG scaffolds and adipose-derived ALDH-positive cells promoted dermal regeneration, giving a possibility that ALDH-positive cells would greatly shorten the waiting period before secondary autologous skin grafting was possible.

The Use of Monoclonal Antibody Directed Chimeric Antigen Receptors to Facilitate Conventional T Cell and Treg Control of GvHD and Tissue Tolerance in Murine Models

INTRODUCTIONRegulatory T cells (Treg) modulate allograft immune responses and Treg-based cellular therapies can be used for prevention of graft-versus-host disease (GvHD) following hematopoietic cell transplantation and for prevention of allograft rejection following tissue or organ transplantation. Treg adoptive transfer has limitations including that Treg do not necessarily home to sites where they are needed and can become inactivated in inflammatory milieus.METHODSWe used new technologies of T cell engineering to force the expression of a chimeric antigen receptor on T cells and Treg that recognizes labeled therapeutic monoclonal antibodies (mabCAR), allowing for precise control of their localization in vivo. The mabCAR recognizes fluorescein isothiocyanate (FITC) through a FITC-specific single-chain variable fragment fused to a CD28 and TCRζ costimulatory domain. Any monoclonal antibody (mab) coupled to FITC within its Fc domain can be recognized. We tested this approach with T cells and Treg to ameliorate GvHD and induce tolerance to pancreatic islet grafts.RESULTSWe first tested our mabCAR construct in conventional T cells (Tcon) which when transfected and stimulated with a FITC-mab become activated and expressed higher levels of CD44 (p=0.0003), CD25 (p=0.009) and produced more IFNγ (p=0.04). To test if mabCAR transient transfection alters Tcon homing after adoptive transfer, we injected luc+ mabCAR Tcon directed against MAdCAM1 (a gut and lymph node endothelial integrin) or SDF1 (a chemokine mainly expressed in the bone marrow) into allogeneic hosts. MAdCAM1-directed Tcon mainly homed to the gut and lymph nodes, while SDF1-directed Tcon homed to bones and spleen. SDF1-directed Tcon induced a milder GvHD (p<0.001), demonstrating that cell homing impacts GvHD severity.We then tested mabCAR Treg ability to maintain their suppressive activity in vitro and in vivo. We found that mabCAR transiently transfected into Treg have increased ability to proliferate in response to anti-CD3/CD28 stimulatory beads (p<0.01) and highly suppress Tcon proliferation when co-cultured with allogeneic irradiated splenocytes. We injected MAdCAM1 directed Treg in an allogeneic GvHD model and these mabCAR Treg prolonged survival (p=0.03), improved GvHD score (p<0.001) and mouse weight profile (p<0.001), thus demonstrating that mabCAR Treg retain regulatory functions.Finally, we tested if mabCAR Treg could induce tolerance to allogeneic pancreatic islet grafts in sublethally irradiated hosts. Luc+gfp+ mabCAR Treg homed and expanded over time (p<0.05) to the site of the allogeneic islet grafts (right kidney capsule) when FITC-anti-allogeneic MHC-I mab directed the Treg as compared to isotype mab controls (see figure). Allo-MHC-I directed mabCAR-Treg prolonged allogeneic islet graft survival in comparison to isotype-mabCAR Treg (p=0.002) allowing for production of higher insulin levels. To assess if allo-MHC-I Treg promoted antigen-specific tolerance, we performed secondary skin graft transplantation. We found that mice which received MHC-I Treg showed a significant delay in the rejection of skin grafts from mice with the same MHC mismatch as the previous islet-allografts in comparison to third-party skin grafts (p=0.02) offering strong evidence that CAR-Treg could be used to enhance antigen-specific graft protection.CONCLUSIONMabCAR expression can be used to control immune cell homing after transfer in different models according to localizing mab availability. We believe that the mabCAR approach may represent a new tool for optimizing cellular therapies to modulate GvHD and for inducing tolerance in islet and organ transplantation. [Display omitted] DisclosuresPierini:Stanford University: Patents & Royalties. Iliopoulou:Stanford University: Patents & Royalties. Negrin:Stanford University: Patents & Royalties. Kim:Stanford University: Patents & Royalties. Meyer:Stanford University: Patents & Royalties.

Primary reattachment of avulsed skin flaps with negative pressure wound therapy in degloving injuries of the lower extremity

Large avulsed skin flaps of the lower extremity caused by degloving injuries eventually develop skin necrosis in most cases. The current treatment option involves excision of the degloved skin and reapplication as a full- or split-thickness skin graft. We considered that reattachment of avulsed skin flaps without excision would be theoretically beneficial, since some circulation may remain around the connected pedicle and thus facilitate graft take. Furthermore, securing the skin to the original anatomic position is much easier using retained landmarks. We treated a total of 12 patients (13 cases) with degloving injuries of the lower extremity. In all cases, the avulsed skin flap was defatted and sewn back to the original position, then negative-pressure wound therapy was applied over those grafts as a bolster for approximately 7 days. Most of the avulsed skin flap took excellently, particularly close to the connected pedicle. Nine cases did not need any additional surgical procedures. Four cases required secondary skin graft for a small area of open wound due to partial necrosis of the defatted skin, as well as the raw surface left by the primary skin defect in the initial operation. Primary reattachment of the avulsed skin flaps without excision is convenient and efficient to cover the open wound over the exposed fascia and periosteum in degloving injuries. This would potentially offer a better alternative to definitive wound closure.

Versatility and “flap efficiency” of pedicled perforator flaps in lower extremity reconstruction

The use of pedicled perforator flaps provides an alternative to free tissue transfer for lower limb reconstruction. We use computer-aided image analysis to investigate the versatility of pedicled perforator flaps for the reconstruction of lower limb defects. Between April 2007 and April 2011, a case series of 61 patients with wounds of the lower extremity from knee to ankle were reconstructed with pedicled perforator flaps. We performed 16 pedicled reverse-flow anterolateral thigh (RF-ALT) flaps, 8pedicled medial sural artery perforator (MSAP) flaps, 26 pedicled peroneal artery perforator (PAP) flaps, and 11 pedicled posterior tibial artery perforator (PTAP) flaps. Digital planimetry of defects covered was analyzed and the "efficiency" of each flap was calculated, which allowed the assessment of the merits of each flap in the management of lower limb defects. Flaps healed primarily in 82% of cases (50/61). Approximately 50% of the secondary donor sites required skin grafting. Complications requiring secondary surgery occurred in 18% (11/61) of the cases. Six required secondary skin grafting (10%). One RF-ALT flap was converted into a free flap, one PAP required arterial supercharging, and three pedicled RF-ALT flaps required venous supercharging. Image analysis showed that these pedicled perforator flaps could cover 75% of the surface area of the lower leg. The higher length of perforator allowed for greater "flap efficiency" and better versatility of tissue cover. Image analysis can be used as a modality to assess the versatility of individual flaps in the reconstruction of lower limb defects.

Abstract: The Usage Of Adipofascial Anterolateral Thigh Flap For The Reconstruction Of Soft Tissue Defects At Extremities

INTRODUCTION: Although reconstruction with adipofascial anterolateral thigh flap (ALTA) is commonly recommended treatment alternative for the extremity defects there are a few studies published in the literature. In this study it was aimed to show the advantageous and disadvantageous of ALTA flap due to experiences that we got from 9 patients at whom superficial extremity defects were reconstructed with ALTA flap. MATERIALS AND METHODS: From 2008 to 2016, 9 patients with extremity defects were treated. All soft tissue defects are superficial and are localized on the hand dorsum in 2 patients, on the palmar aspect of left hand in one patient, on the right wrist in 2 patients, on the left wrist in 2 patients, on the knee in one patient and on the foot dorsum in remaining patient. Wounds were prepared by serial debridement and closed with ALTA flap as soon as possible. During the separation of the flap a minimum of 3 mm fat (a little bit more around the perforator vessel entry) should be preserved over the fascia to ensure the vascularity of the flap. The flaps were inset to the defect adipose side upward in three patient and downward in 4 patients. RESULTS: Eight of nine flaps were supplied with musculocutaneous perforators, while the remaining flap was supplied with septocutaneous perforator. The overall flap survival rate was 100 %. In three cases, which all are adipose tissue up-ward inset flaps, partial skin graft loss occurred. Secondary skin grafting was performed and the wounds closed successfully. Other flaps have also minor graft loss due to minor hematoma, but these areas do not need any surgical intervention and epithelized spontaneously. No secondary debulking procedures were required in any of the flap. All of the donor sites were closed directly with acceptable appearance, minimal donor site morbidity and no contour deformation except in one patient. In that patient wound dehiscence was occurred in the donor site incision. The wound was closed with split thickness skin graft. CONCLUSION: In this study we observed that ALTA flap is an appropriate choice for the reconstruction of soft tissue defects at the extremity. The main advantages of the flap are; sufficient size and pedicle length with pliable structure, minimal donor side morbidity, good aesthetic result and prevention of adhesions. DISCLOSURE:None of the authors has a financial interest in any of the products, devices, or drugs mentioned in this manuscript

Patterns of etiologies and soft tissue defects in the upper limb and use of different reconstruction modalities

A total of 48 cases of soft tissue defects of upper limb were managed during one calendar year. This included 34 males and 14 females. Post burn complication was the most common etiology. Ten cases had machine injury while other 6 cases had household trauma. Another group of six cases had injuries during fireworks at various ceremonies. Whereas 17 cases were dealt by simple measures like healing by secondary intension, primary closure and skin grafting, 31 cases needed soft tissue coverage with various flaps. Only ten cases were dealt with the help of local flaps while rest of the 21 cases needed various regional and distant flaps.

Combined Anti-CD154/CTLA4Ig Costimulation Blockade-Based Therapy Induces Donor-Specific Tolerance to Vascularized Osteomyocutaneous Allografts.

Tolerance induction by means of costimulation blockade has been successfully applied in solid organ transplantation; however, its efficacy in vascularized composite allotransplantation, containing a vascularized bone marrow component and thus a constant source of donor-derived stem cells, remains poorly explored. In this study, osteomyocutaneous allografts (alloOMCs) from Balb/c (H2(d) ) mice were transplanted into C57BL/6 (H2(b) ) recipients. Immunosuppression consisted of 1 mg anti-CD154 on day 0, 0.5 mg CTLA4Ig on day 2 and rapamycin (RPM; 3 mg/kg per day from days 0-7, then every other day for 3 weeks). Long-term allograft survival, donor-specific tolerance and donor-recipient cell trafficking were evaluated. Treatment with costimulation blockade plus RPM resulted in long-term graft survival (>120 days) of alloOMC in 12 of 15 recipients compared with untreated controls (median survival time [MST] ≈10.2 ± 0.8 days), RPM alone (MST ≈33 ± 5.5 days) and costimulation blockade alone (MST ≈45.8 ± 7.1 days). Donor-specific hyporesponsiveness in recipients with viable grafts was demonstrated in vitro. Evidence of donor-specific tolerance was further assessed in vivo by secondary donor-specific skin graft survival and third-party graft rejection. A significant increase of Foxp3(+) regulatory T cells was evident in tolerant animals. Donor cells populated peripheral blood, thymus, and both donor and recipient bone marrow. Consequently, combined anti-CD154/CTLA4Ig costimulation blockade-based therapy induces donor-specific tolerance in a stringent murine alloOMC transplant model.

皮膚再建の再生医療

Skin has been a subject of generative medicine for long time. Technique of culture of human epithelium had been established in 1975 and the use of cultured epithelium is now major treatment option in management of extensive burn patients. However, the grafted cultured epithelium keeps rather fragility for several months after grafting, which is a current unsolved problem. We tested the effects of DFAT (dedifferentiated fat cells) on regeneration of basement membrane after cultured epithelial grafting in porcine experimental model. The result showed that the DFAT enhanced the laminin-5 supply and anchoring fibril formation, which may be beneficial to promote maturity of grafted cultured epithelium. Artificial dermis (AD) is a dermal regeneration template consisting of a spongy, porous collagen dermal replacement layer and a temporary epidermal substitute made of silicone. The advantage using AD to treat skin defects is that tissue quality resembling that with a full-thickness skin graft can be obtained with a thin split-thickness skin graft, which minimizes donor site morbidity. However, this treatment method requires two separate procedures, because the AD must be vascularized before skin grafting. Currently, reducing the time required for dermis-like tissue generation before the secondary skin grafting is desired. We tested the effects of DFAT on vascularization of the AD in rat experimental model. The result showed that the DFAT enhanced the angiogenesis, especially under bFGF treatment. We confirmed that one-step grafting procedure of the artificial dermis and the skin is possible by this method in porcine experimental model.

Reconstruction of complex soft-tissue defects in the extremities with chimeric anterolateral thigh perforator flap

IntroductionThe reconstruction of extensive three-dimensional defects in the extremities is a difficult challenge. Many attempts have been made to reconstruct such defects using the chimeric flap concept, enabling flaps with larger surface areas to be used while maintaining economical tissue use. The anterolateral thigh (ALT) chimeric flap is one of the most useful tools for the reconstruction of complex three-dimensional defects in the extremities. MethodsFrom January 2010 to March 2012, Twenty-two patients underwent extremity reconstruction using chimeric ALT perforator flaps, which consists of a skin component on its isolated perforator and a portion of the fascia and muscle flaps on the same pedicle from the descending branch of the lateral circumflex femoral artery (LCFA). The defects were in either a lower (n = 10) or an upper extremity (n = 12). The area of the soft tissue defects ranged from 43 × 35 cm to 19 × 9 cm (mean, 25 × 18 cm), containing extensive, irregular, ring-like soft tissue defects or degloving injuries. ResultsThe mean dimension of skin flap was 19.8 × 11.2 cm. The mean dimension of fascia flap was 8.9 × 7.1 cm. The mean dimension of muscle flap was 11.1 × 7.5 cm. No total flap loss occurred. One patient presented with venous thrombosis, and re-anastomosis and vein grafting were performed. Two cases exhibiting partial skin graft loss at the site at which the fascia flap was inset were treated via secondary skin grafts. During a follow-up period of 18 months–30 months, patients were satisfied with the functional and aesthetic outcome. No serious donor-site complications occurred. DiscussionChimeric anterolateral thigh perforator flap can be one of the best choice for reconstruction of complex soft-tissue defects in the extremities. ConclusionsThe various tissue components and maximal freedom offered by chimeric tissue flaps associated with the same descending branch of the LCFA provide versatile coverage of large, complex, and irregular soft-tissue defects in the extremities.