An optimized dual-surgeon simultaneous orthotopic hind-limb allotransplantation model in rats.

Composite tissue allograft (CTA) transplantation is a promising treatment in reconstructive surgery for complex tissue injuries in humans. However, continued research is required to optimize the risk to benefit ratios. In this study, we describe, in detail, an optimized simultaneous dual-surgeon orthotopic hind-limb transplantation model in direct comparison to a single-surgeon model. In this study 75 hind-limb CTAs were performed, employing either a dual-surgeon model (n = 60) or a single-surgeon model (n = 15) for the transplantation of two hind-limbs. Operative times, complication rates, and costs were compared. The dual-surgeon approach showed a significant reduction of 45.4% in overall operative time (p < 0.05). Overall complication rate was 8%. The dual-surgeon model was ∼30.5% more cost-effective than the traditional single-surgeon approach. Benefits of the proposed simultaneous dual-surgeon orthotopic rat hind-limb CTA model include decreased operating times, decreased complication rates, and reduced financial costs when compared with the established single-surgeon model.

Proliferation of fibroblasts cultured on a hemi-cellulose dressing.

In recent times, hemi-cellulose dressing (HD) has been used clinically with satisfactory rates of success [Melandri D, De Angelis A, Orioli R, et-al. Use of a new hemicellulose dressing (Veloderm) for the treatment of split-thickness skin graft donor sites A within-patient controlled study. Burns 2006 Dec;32:964-72.]; however, the effect of cellulose dressings on the wound-healing process is unclear due to paucity of experimental data. This study aimed to determine the adhesion and proliferation of human skin fibroblasts, which were cultured in vitro using the explant technique, on HD. Cells were seeded onto HD discs and evaluated for cell adhesion and cell proliferation after 7, 14 and 21 days. Fibroblasts displayed 70% adhesion to HD after 24h. The HD discs seeded with a density of 5x10(4) cells per well showed a proliferation rate of 12% on day 7, 30% on day 14 and 75% on day 21. The results demonstrated that HD can sustain fibroblast proliferation--a highly desirable characteristic for an ideal skin substitute.

Daily topical tacrolimus therapy prevents skin rejection in a rodent hind limb allograft model.

BACKGROUND: Skin is the most immunogenic component of a composite tissue allograft. Topical immunotherapy is an attractive therapeutic modality with which to provide local immunosuppression, with minimal systemic toxicity. The present study was performed to investigate the potential of topical tacrolimus to prolong survival of the skin component of a composite tissue allograft. METHODS: Wistar Furth-to-Lewis rat orthotopic hind limb transplants were performed. Group I consisted of rats treated with topical tacrolimus; group II, antilymphocyte serum plus 21 days cyclosporine; and group III, antilymphocyte serum plus 21 days of cyclosporine plus topical tacrolimus. In group IV, tacrolimus levels in blood, skin, and muscle were measured in an autograft control group. RESULTS: All animals in group I (n = 8) developed grade III clinical rejection by postoperative day 9. In group II (n = 9), the median onset of grade III rejection was postoperative day 40 (range, postoperative days 34 to 44). In group III (n = 6), two animals developed focal grade III rejection on postoperative days 35 and 56. The remaining four animals reached the 100-day endpoint without grade III rejection. In group IV, tacrolimus levels were low or undetectable in blood, whereas skin levels were 100-fold higher than underlying muscle. CONCLUSIONS: Topical tacrolimus therapy has the potential to prevent skin rejection in a composite tissue allograft. Preoperative depletion of T cells with antilymphocyte serum, along with a short course of systemic immunosuppression, prevents acute rejection, whereas topical tacrolimus inhibits immune cell function in the skin. Concentrations of tacrolimus are substantially higher in skin compared with underlying muscle and peripheral blood. Topical immunotherapy could reduce the morbidity associated with systemic immunosuppression in clinical composite tissue allografts.

A model for functional recovery and cortical reintegration after hemifacial composite tissue allotransplantation.

BACKGROUND: The ability to achieve optimal functional recovery is important in both face and hand transplantation. The purpose of this study was to develop a functional rat hemifacial transplant model optimal for studying both functional outcome and cortical reintegration in composite tissue allotransplantation. METHODS: Five syngeneic transplants with motor and sensory nerve appositions (group 1) and five syngeneic transplants without nerve appositions (group 2) were performed. Five allogeneic transplants were performed with motor and sensory nerve appositions (group 3). Lewis (RT1) rats were used for syngeneic transplants and Brown-Norway (RT1) donors and Lewis (RT1) recipients were used for allogeneic transplants. Allografts received cyclosporine A monotherapy. Functional recovery was assessed by recordings of nerve conduction velocity and cortical neural activity evoked by facial nerve and sensory (tactile) stimuli, respectively. RESULTS: All animals in groups 1 and 3 showed evidence of motor function return on nerve conduction testing, whereas animals in group 2, which did not have nerve appositions, did not show electrical activity on electromyographic analysis (p < 0.001). All animals in groups 1 and 3 showed evidence of reafferentation on recording from the somatosensory cortex after whisker stimulation. Animals in group 2 did not show a cortical response on stimulation of the whiskers (p < 0.001). CONCLUSION: The authors have established a hemiface transplant model in the rat that has several modalities for the comprehensive study of motor and sensory recovery and cortical reintegration after composite tissue allotransplantation.

Long-term survival of limb allografts induced by pharmacologically conditioned, donor alloantigen-pulsed dendritic cells without maintenance immunosuppression.

BACKGROUND: We showed recently that limb allograft survival could be enhanced by administration of alloantigen (Ag)-pulsed immature dendritic cells (DC) after transplantation. Since indefinite graft survival was not achieved, we have further modified the DC by pharmacologic (rapamycin; Rapa) conditioning and ascertained their influence on graft survival, without continued immunosuppressive therapy. METHODS: We compared the ability of donor Ag-pulsed, Rapa-conditioned rat myeloid DC (Rapa DC) and control DC (CTR DC) to inhibit alloreactive T-cell responses after limb transplantation in antilymphocyte serum (ALS)-treated recipients given a short postoperative course of cyclosporine (CsA). RESULTS: Both DC populations expressed similar levels of major histocompatibility complex (MHC) II, CD40 and CD54, but Rapa DC expressed lower CD86. After toll-like receptor activation, both populations produced minimal interleukin (IL)-12p70, but Rapa DC secreted lower levels of IL-6 and IL-10. The capacity of DCs to stimulate T-cell proliferation in mixed leukocyte reactions was very low. Pulsing of the DC with donor Ag did not alter their phenotype or function. Interestingly, posttransplant administration of donor Ag-pulsed Rapa DC to rats given perioperative ALS and 21 days CsA significantly delayed graft rejection and promoted long-term (>125 days) graft survival. AlloAg-pulsed Rapa DC induced T-cell hyporesponsiveness and promoted the generation of IL-10-secreting CD4 T cells upon ex vivo challenge. CONCLUSIONS: Infusion of donor Ag-pulsed, Rapa-conditioned DC after composite tissue transplantation can prevent rejection of the grafts, including skin, across a full MHC mismatch and in the absence of continued immunosuppressive therapy.

Rapamycin-conditioned, alloantigen-pulsed dendritic cells promote indefinite survival of vascularized skin allografts in association with T regulatory cell expansion.

Clinically-applicable protocols that promote tolerance to vascularized skin grafts may contribute to more widespread use of composite tissue transplantation. We compared the properties of alloantigen (Ag)-pulsed, rapamycin (Rapa)-conditioned and control bone marrow-derived host myeloid dendritic cells (DCs) and their potential, together with transient immunosuppression (anti-lymphocyte serum+cyclosporine), to promote long-term, vascularized skin graft survival in Lewis rats across a full MHC barrier. Both types of DCs expressed low levels of CD86, but Rapa DC expressed lower levels of MHC II and CD40 and were less stimulatory in MLR. While both Rapa and control DCs produced low levels of IL-12p70 and moderate levels of IL-6 and IL-10 following TLR ligation, Rapa DC secreted significantly lower levels of IL-6 and IL-10 in response to LPS. Donor Ag-pulsed Rapa DC, but not control DC, induced long-term skin graft survival (median survival time >133 days) when administered 7 and 14 days post-transplant. Circulating T cells in hosts with long-surviving grafts were hyporesponsive to donor alloAg stimulation, but proliferated in response to third-party stimulation and produced IFN-gamma and IL-10. When recipients of long-surviving grafts were challenged with skin grafts, donor but not third-party grafts were prolonged, suggesting underlying regulatory mechanisms. Both flow cytometry and immunohistochemical analysis revealed that donor Ag-pulsed Rapa DC infusion expanded CD4+ Foxp3+ Treg in recipients' spleens, graft-associated lymph nodes and the graft. These data demonstrate for the first time that pharmacologically-modified, donor Ag-pulsed host DC administered post-transplant can promote indefinite vascularized skin graft survival, associated with Treg expansion.

Cellular therapies for prolongation of composite tissue allograft transplantation.

Complex musculoskeletal defects resulting from cancer, congenital absence, and trauma represent a unique reconstructive challenge. Autologous tissue is often unavailable to reconstruct these deformities. Composite tissue allograft transplantation represents a unique solution for these clinical problems. Face, hand, or limb transplants can be performed in a single procedure. However, the use of chronic nonspecific systemic immunosuppression can lead to side effects such as drug toxicity, opportunistic infections, and malignancies. This article explores various cell-based therapies that represent promising modalities to reduce chronic immunosuppression and alter the risk/benefit ratios for the prospect of composite tissue allograft transplantation.

Perfil epidemiológico de fraturas mandibulares tratadas na Universidade Federal de São Paulo: Escola Paulista de Medicina / Epidemiological profile of mandible fractures treated at the Federal University of São Paulo: Paulista Medical School

OBJETIVO: As fraturas mandibulares podem levar a grandes prejuízos estéticos, funcionais e financeiros e suas características epidemiológicas têm sofrido alterações em diversas localidades. Para detectar estas mudanças, foi realizado este estudo, cujo objetivo foi comparar os dados de pacientes com fraturas mandibulares atendidos no Hospital São Paulo (UNIFESP-EPM) no período de junho de 1999 a março de 2002 aos de pacientes atendidos de janeiro de 1991 a março de 1996. MÉTODOS: Foram comparados o sexo e faixa etária mais acometidos, locais mais fraturados do osso, lesões associadas, tratamento e complicações de 98 pacientes com fratura de mandíbula, atendidos pelo Setor de Cirurgia Craniofacial da Disciplina de Cirurgia Plástica UNIFESP-EPM no período de junho de 1999 a março de 2002 aos mesmos dados de 166 pacientes atendidos de janeiro de 1991 a março de 1996. RESULTADOS: O sexo e a faixa etária mais acometidos ainda são os mesmos. Os acidentes de transporte, como principais causas de fraturas mandibulares, foram substituídos pelas agressões. Houve diminuição de lesões associadas e de fraturas múltiplas na mandíbula, provavelmente associadas à mudança etiológica. O local mais acometido continua sendo o corpo. O tratamento mais utilizado nos dois grupos foi a fixação com miniplaca, e o número de complicações diminuiu, provavelmente devido à melhora do padrão de atendimento. CONCLUSAO: Houve mudanças nas características epidemiológicas das fraturas mandibulares na população de São Paulo e o conhecimento das mesmas possibilita a instituição de medidas preventivas e de tratamento adequadas.

[Epidemiological profile of mandible fractures treated at the Federal University of São Paulo-Paulista Medical School]. / Perfil epidemiológico de fraturas mandibulares tratadas na Universidade Federal de São Paulo-Escola Paulista de Medicina.

BACKGROUND: Mandible fractures can result in esthetic, functional and financial problems and their epidemiological patterns have changed in many locations. This study was carried out to detect these changes, aiming to compare data of patients with mandible fractures treated at the Sao Paulo Hospital (UNIFESP-EPM) from June 1999 to March 2002 with data of patients treated from January 1991 to March 1996. METHODS: Information on most affected gender and age, most often fractured mandible segment, associated injuries, treatment and complications of 98 victims of mandible fracture admitted from June 1999 to March 2002 were compared to the same data of 166 patients treated from January 1991 to March 1996. RESULTS: the most affected gender and age ranges remain the same. Aggressions surpassed traffic accidents as the main etiology. Incidence of associated injuries and multiple fractures in the mandible decreased, a fact probably related to the change in etiology. The most affected segment is still the body of the mandible. The most used type of treatment in both samples was internal rigid fixation with miniplates and the number of complications decreased, due to the higher standard of patient care. CONCLUSION: Mandible fractures in the São Paulo population have undergone epidemiological changes and this knowledge enables local authorities to establish adequate measures for prevention and treatment.