Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 272
Filtrar
Mais filtros










Filtros aplicados

Base de dados
Intervalo de ano de publicação
2.
Plast Reconstr Surg ; 145(4): 757e-768e, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32221215

RESUMO

BACKGROUND: Transplantation of vascularized composite allografts is limited mainly by the need for life-long immunosuppression. The consequent side effects and looming specter of chronic rejection portend eventual allograft loss. Development of tolerogenic protocols is thus of utmost importance to the field of vascularized composite allograft transplantation. METHODS: With a modified delayed tolerance induction protocol, 10 cynomolgus macaques received hand (n = 2) or face vascularized composite allografts across both full and haploidentical major histocompatibility complex barriers before donor bone marrow transplantation at a later date. Protocol and for-cause allograft skin biopsies were performed for immunohistochemical analysis and analysis of donor-recipient leukocyte contribution; mixed chimerism in peripheral blood and in vitro immune responses were assessed serially. RESULTS: Before bone marrow transplantation, maintenance immunosuppression for 4 months led to lethal complications, including posttransplant lymphoproliferative disorder (in two of four recipients), which necessitated early study termination. Shortening the maintenance period to 2 months was clinically relevant and allowed all subsequent subjects (n = 6) to complete the delayed tolerance induction protocol. Acute rejection developed within the first 2 to 4 weeks after transplantation, with corresponding near-complete turnover of allograft leukocytes from donor to recipient origin, but donor-specific antibodies remained negative. After bone marrow transplantation, mixed chimerism failed to develop, although carboxyfluorescein succinimidyl ester mixed lymphocyte reaction demonstrated generalized unresponsiveness. However, the accrual of subsequent rejection episodes eventually culminated in graft vasculopathy and irreversible allograft loss. CONCLUSIONS: Despite the various advantages of the delayed tolerance induction protocol, it failed to reliably induce mixed chimerism and thus immunologic tolerance to vascularized composite allografts, given currently available immunosuppression treatment options. Ongoing work shows promise in overcoming these limitations.


Assuntos
Aloenxertos Compostos/imunologia , Rejeição de Enxerto/prevenção & controle , Tolerância Imunológica , Condicionamento Pré-Transplante/métodos , Alotransplante de Tecidos Compostos Vascularizados/efeitos adversos , Animais , Biópsia , Transplante de Medula Óssea/métodos , Aloenxertos Compostos/patologia , Aloenxertos Compostos/transplante , Modelos Animais de Doenças , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/patologia , Sobrevivência de Enxerto/imunologia , Humanos , Imunossupressão/efeitos adversos , Imunossupressão/métodos , Imunossupressores/administração & dosagem , Imunossupressores/efeitos adversos , Leucócitos/imunologia , Teste de Cultura Mista de Linfócitos , Transtornos Linfoproliferativos/epidemiologia , Transtornos Linfoproliferativos/etiologia , Macaca fascicularis , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/etiologia , Pele/irrigação sanguínea , Pele/imunologia , Pele/patologia , Quimeras de Transplante/imunologia , Condicionamento Pré-Transplante/efeitos adversos , Transplante Homólogo/efeitos adversos , Falha de Tratamento , Alotransplante de Tecidos Compostos Vascularizados/métodos
3.
Medicine (Baltimore) ; 99(1): e18612, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31895813

RESUMO

BACKGROUND: Uterus transplantation is a complex, multi-step experimental procedure used for the treatment of uterus absence or uterus anomaly that prevents embryo implantation or pregnancy completion. METHOD: To date, only 51 uterus transplants worldwide had been performed. When simplified, it is vascularized composite allograft transplantation. While it is still an experimental procedure with encouraging results for the future, there are still many issues that have to be clarified. The most serious complications of uterus transplantation are graft rejection or grafts vascular failure. RESULTS: So far, no reference to the atherosclerotic arterial infiltration of the uterus arteries was suggested and studied as one of the main causes of graft's failure. CONCLUSION: In this review we summarized current knowledge and possible role of uterus arterial damage, including atherosclerotic changes on the graft's survival.


Assuntos
Aterosclerose/etiologia , Artéria Uterina , Útero/transplante , Alotransplante de Tecidos Compostos Vascularizados/efeitos adversos , Feminino , Humanos , Óxido Nítrico/metabolismo , Túnica Íntima/metabolismo , Útero/irrigação sanguínea , Remodelação Vascular
4.
Int J Oral Maxillofac Surg ; 49(2): 169-175, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31235388

RESUMO

Chronic vascular rejection characterized by the myointimal proliferation of smooth muscle cells that progressively obstruct the arterial graft lumen may become the main cause of long-term graft loss in vascularized composite allotransplantation (VCA), as observed in solid organ transplantation. As such, new diagnostic tools are required. The objective of this study was to evaluate the usefulness of flow magnetic resonance imaging (MRI) in the qualitative and quantitative monitoring of VCA in three patients transplanted between 2005 and 2012. Seven flow MRI acquisitions were performed concurrently with standardized clinical and histological monitoring between 2015 and 2017. A progressive reduction in the average flow rate and intraluminal diameter of the arterial pedicle of the grafts was demonstrated. During follow-up, two patients developed chronic vascular rejection requiring partial resection of the graft. For these patients, flow MRI acquisitions were characterized by a significant reduction in vascular signal, with a reduction in intravascular flow prior to anatomical injury. The results of this study confirm the feasibility of reproducible, non-invasive, and non-operator-dependent morphometric and haemodynamic radiological analysis, providing clinicians with new information on the vascular status of VCA over time and offering the prospect of an imaging technique specific to vascular outflow.


Assuntos
Rejeição de Enxerto , Alotransplante de Tecidos Compostos Vascularizados , Humanos , Imagem por Ressonância Magnética
5.
J Orthop Res ; 38(2): 288-296, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31579953

RESUMO

Vascularized composite allotransplantation of bone is a possible alternative treatment for large osseous defects but requires life-long immunosuppression. Surgical induction of autogenous neo-angiogenic circulation maintains transplant viability without this requirement, providing encouraging results in small animal models [1-3]. A preliminary feasibility study in a swine tibia model demonstrated similar findings [4, 5]. This study in swine tibial allotransplantation tests its applicability in a pre-clinical large animal model. Previously, we have demonstrated bone vascularized composite allotransplantation (VCA) survival was not the result of induction of tolerance nor an incompetent immune system [1]. Fourteen tibia vascularized bone allotransplants were microsurgically transplanted orthotopically to reconstruct size-matched tibial defects in Yucatan miniature swine. Two weeks of immunosuppression was used to maintain allotransplant pedicle patency during angiogenesis from a simultaneously implanted autogenous arteriovenous bundle. The implanted arteriovenous bundle was patent in group 1 and ligated in group 2 (a neo-angiogenesis control). At twenty weeks, we quantified the neo-angiogenesis and correlated it with transplant viability, bone remodeling, and gene expression. All patent arteriovenous bundles maintained patency throughout the survival period. Micro-angiographic, osteocyte cell count and bone remodeling parameters were significantly higher than controls due to the formation of a neo-angiogenic autogenous circulation. Analysis of gene expression found maintained osteoblastic and osteoclastic activity as well as a significant increase in expression of endothelial growth factor-like 6 (EGFL-6) in the patent arteriovenous bundle group. Vascularized composite allotransplants of swine tibia maintained viability and actively remodeled over 20 weeks when short-term immunosuppression is combined with simultaneous autogenous neo-angiogenesis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:288-296, 2020.


Assuntos
Transplante Ósseo , Alotransplante de Tecidos Compostos Vascularizados , Animais , Biomarcadores/metabolismo , Remodelação Óssea , Osso e Ossos/metabolismo , Expressão Gênica , Masculino , Neovascularização Fisiológica , Suínos , Porco Miniatura
6.
Int J Immunogenet ; 47(1): 24-27, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31867873

RESUMO

This short review will be concerned with the literature that has developed connected with the immunogenetic and tissue compatibility aspects of hand transplantation and will also draw on connected work in the more general area of vascularized composite allotransplantation (VCA) which includes face, abdominal wall uterus and larynx.


Assuntos
Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto/imunologia , Antígenos HLA/imunologia , Transplante de Mão , Histocompatibilidade/imunologia , Humanos , Imunização , Alotransplante de Tecidos Compostos Vascularizados
7.
Proc Natl Acad Sci U S A ; 116(51): 25784-25789, 2019 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-31792185

RESUMO

For individuals who sustain devastating composite tissue loss, vascularized composite allotransplantation (VCA; e.g., hand and face transplantation) has the potential to restore appearance and function of the damaged tissues. As with solid organ transplantation, however, rejection must be controlled by multidrug systemic immunosuppression with substantial side effects. As an alternative therapeutic approach inspired by natural mechanisms the body uses to control inflammation, we developed a system to enrich regulatory T cells (Tregs) in an allograft. Microparticles were engineered to sustainably release TGF-ß1, IL-2, and rapamycin, to induce Treg differentiation from naïve T cells. In a rat hindlimb VCA model, local administration of this Treg-inducing system, referred to as TRI-MP, prolonged allograft survival indefinitely without long-term systemic immunosuppression. TRI-MP treatment reduced expression of inflammatory mediators and enhanced expression of Treg-associated cytokines in allograft tissue. TRI-MP also enriched Treg and reduced inflammatory Th1 populations in allograft draining lymph nodes. This local immunotherapy imparted systemic donor-specific tolerance in otherwise immunocompetent rats, as evidenced by acceptance of secondary skin grafts from the hindlimb donor strain and rejection of skin grafts from a third-party donor strain. Ultimately, this therapeutic approach may reduce, or even eliminate, the need for systemic immunosuppression in VCA or solid organ transplantation.


Assuntos
Micropartículas Derivadas de Células/metabolismo , Imunossupressão/métodos , Linfócitos T Reguladores/citologia , Tolerância ao Transplante/fisiologia , Alotransplante de Tecidos Compostos Vascularizados/métodos , Animais , Citocinas/metabolismo , Sistemas de Liberação de Medicamentos , Imunossupressores/metabolismo , Ratos
8.
Soins ; 64(839): 14-19, 2019 Oct.
Artigo em Francês | MEDLINE | ID: mdl-31783940

RESUMO

Vascularized Composites Allotransplantation are today out of the experimental stage to enter a rare but codified practice whose results are known. Beyond the surgical procedure and the treatment, accompaniment by paramedical personnel is essential for the proper performance of the graft a to treatment coping and the functional results. Specific actions taken by health care personnel throughout care also includes their importance.


Assuntos
Rejeição de Enxerto , Alotransplante de Tecidos Compostos Vascularizados , Humanos
9.
J Clin Ethics ; 30(4): 318-330, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31851623

RESUMO

As the field of vascularized composite allotransplantation (VCA) continues to evolve and technological approaches improve, VCA programs must focus on promoting greater consistency in psychosocial assessment across programs to support the equitable selection of patients. Based on a summary of published reports of VCA, we address the ethical considerations raised by the present heterogeneity of approaches to psychosocial assessment, including weighing risks and benefits, informed consent and the role of decisional capacity, and potential or perceived bias in the assessment process. We propose transparency of process across the field and encourage VCA programs to work collaboratively to share approaches to psychosocial assessment both pre- and post-transplant to promote health equity.


Assuntos
Seleção de Pacientes , Alotransplante de Tecidos Compostos Vascularizados/ética , Humanos , Consentimento Livre e Esclarecido , Alotransplante de Tecidos Compostos Vascularizados/psicologia
11.
Curr Opin Organ Transplant ; 24(6): 714-720, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31577596

RESUMO

PURPOSE OF REVIEW: Vascularized composite allotransplantation (VCA), a life-enhancing treatment for patients with complex tissue defects, trauma or illness, expounds upon the foundation of solid organ transplantation (SOT), the gold standard in end-stage organ failure. As innate and adaptive immunity remain the fundamental concern, this review highlights divergent immunobiology responses in VCA and SOT recipients. RECENT FINDINGS: Host innate immune activation drives peritransplant tissue ischemia-reperfusion injury (IRI). Despite the direct relationship between ischemia-reperfusion (IR)-stress and cell-mediated acute rejection, the mechanism of how IRI may affect VCA loss needs investigation. With skin grafts being highly immunogenic, the incidence of cell-mediated rejection is higher in VCA than SOT; whereas ex-vivo perfusion may exert cytoprotection against IRI in VCA and SOT. New treatment concepts, such as topical immunosuppression or cell-based tolerogenic therapies, may avoid systemic immunosuppression in VCA. Although antibody-mediated rejection is relatively rare in VCA and its disease seems to be distinct from that in SOT, little is known as to whether and how IRI may influence humoral immune rejection cascade in VCA or SOT. SUMMARY: Further understanding of the innate-adaptive immune crosstalk should contribute to much needed development of novel therapies to improve VCA outcomes, based on strategies established in SOT.


Assuntos
Imunossupressão/métodos , Transplante de Órgãos/métodos , Humanos , Alotransplante de Tecidos Compostos Vascularizados
12.
Curr Opin Organ Transplant ; 24(6): 721-725, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31599761

RESUMO

PURPOSE OF REVIEW: Vascularized composite allotransplantation (VCA) has developed over the past 20 years, resulting in promising new reconstructive prospects for extensive soft tissue defects. More than 200 VCAs have been performed worldwide, including five genitourinary (GU)VCAs and here we review the most recent literature in this field. RECENT FINDINGS: Developments in GUVCA are continuously evolving to improve patient outcomes and suggest ethical equivalency to solid organ transplant. Recent treatment options have focused on preventing GUVCA complications by acknowledging the immunogenic tissue composition of the penis to treat rejection episodes and implementing stem cell transplant to recognized the GUVCA as self. Utilizing modern, postoperative, treatments can minimize complications and although the ethical dilemma remains, the morality of performing a GUVCA has diminished. The ethical focus relic's on standardization of patient safety. SUMMARY: GUVCA has become an established reconstructive surgical option. The prospect of VCA's future insinuates systemization between multidisciplinary VCA programs and the United Network for Organ Sharing in efforts to endorse ethical standardization. Over the last five years, the unprecedented outcomes have shown purpose to GUVCA that initiates an obligation to help those with severe genitourinary tissue defects. Progress in immunobiology continues to evolve optimal immunosuppression drug regimens and tolerance induction protocols, highlighting potential new immunologic pathways for graft acceptance.


Assuntos
Imunossupressão/métodos , Transplante de Órgãos/métodos , Pênis/transplante , Sistema Urogenital/cirurgia , Alotransplante de Tecidos Compostos Vascularizados/métodos , Humanos , Masculino
13.
Microsurgery ; 39(8): 737-747, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31471984

RESUMO

BACKGROUND: The reduction of systemic immunosuppressive agents is essential for the expansion of vascularized composite allotransplantation (VCA) in a clinical setting. The purpose of this study is to compare human-induced pluripotent stem cell-derived mesenchymal stem cells (iMSCs) with four other types of mesenchymal stem cells (human bone marrow-derived MSCs [BMMSCs], human adipose-derived MSCs [ADMSCs], rat BMMSCs, and rat ADMSCs) in vitro, and to investigate the in vivo immunomodulatory effect of iMSCs in a rat VCA model. MATERIALS AND METHODS: One Brown Norway (BN) rat, 2 Lewis (LEW) rats, and 1 Wistar rat were used in the mixed lymphocyte reaction (MLR), and 9 BN rats and 3 LEW rats (for donors), and 24 LEW rats (for recipients) were used in the VCA model. The abovementioned five types of MSCs were imaged to examine their morphology and were also tested for suppressor function using a MLR. The 24 recipient LEW rats were divided randomly into four groups, and subjected to orthotopic hind limb transplantation. The three control groups were the Iso group, in which transplantation was performed on from three to six LEW rats without immunosuppressive treatment (n = 6); the FK group, in which transplantation was performed from BN rats to LEW rats and recipient rats were treated with tacrolimus alone (FK 506, 0.2 mg/kg, days 0-6 postoperatively, intraperitoneally) (n = 6); and the UT group, in which transplantation was performed from BN rats to LEW rats without any immunosuppressive treatment (n = 6). The experimental group was the iMSC group, in which transplantation was performed from BN rats to LEW rats and recipient rats were treated with tacrolimus (FK 506, 0.2 mg/kg, days 0-6 postoperatively, intraperitoneally) and injected with iMSCs (2 × 106 cells, day 7, intravenously) (n = 6). Hind limb survival was assessed by daily inspection of gross appearance until 50 days postoperatively. Histology of the skin and muscle biopsy were investigated on day 14 postoperatively. A time series of the plasma cytokine level (before transplantation, and at 10, 14, and 17 days after transplantation) was also analyzed. RESULTS: The size of adherent and trypsinized iMSCs was 67.5 ± 8.7 and 9.5 ± 1.1 µm, respectively, which was the smallest among the five types of MSCs (p < .01). The absorbance in MLR was significantly smaller with rat ADMSCs (p = .0001), human iMSCs (p = .0006), rat BMMSCs (p = .0014), human ADMSCs (p = .0039), and human BMMSCs (p = .1191) compared to without MSCs. In vivo, iMSC treatment prolonged hind limb survival up to 12.7 days in macroscopic appearance, which is significantly longer than that of the FK group (p < .01). Histology of the skin and muscle biopsy revealed that mononuclear cell infiltration was significantly reduced by iMSC injection (p < .01). iMSC treatment also affected proinflammatory cytokines (interferon-gamma (IFNγ) and tumor necrosis factor α (TNFα)) and the anti-inflammatory cytokine (interleukin-10 (IL-10)) of the recipient plasma. The IFNγ levels at Δ14 and the TNFα levels at Δ14 and Δ17 of the iMSC group were significantly lower than those of the FK group (p = .0226, .0004, and .004, respectively). The IL-10 levels at Δ10 and Δ14 of the iMSC group were significantly higher than those of the FK group (p = .0013 and .0374, respectively). CONCLUSIONS: iMSCs induce T cell hyporesponsiveness to prolong hind limb survival in a rat VCA model. This immunomodulatory property against acute rejection could provide one of the promising strategies capable of enabling the toxicities of immunosuppressants to be avoided in clinical settings.


Assuntos
Sobrevivência de Enxerto , Membro Posterior/cirurgia , Células-Tronco Pluripotentes Induzidas , Transplante de Células-Tronco Mesenquimais , Alotransplante de Tecidos Compostos Vascularizados , Animais , Masculino , Modelos Animais , Distribuição Aleatória , Ratos , Ratos Endogâmicos BN , Ratos Endogâmicos Lew , Ratos Wistar
14.
J Vasc Res ; 56(4): 163-180, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31266018

RESUMO

Vascularized composite allotransplantation (VCA) has emerged as a useful reconstructive option for patients suffering from major tissue defects and functional deficits. While the technical feasibility has been optimized and more than 130 VCAs have been performed during the last two decades, hurdles such as acute and chronic allograft rejection, graft deterioration, and eventual functional impairment need to be addressed. Recently, chronic graft rejection and progressive failure have been linked to vascular alterations observed in the allografts. Graft vasculopathy (GV) may play a pivotal role in long-term graft deterioration. The understanding of the underlying pathophysiological processes and their initial triggers is of utmost importance in the prevention, attenuation, and therapy of GV. While there are reports on the etiology and development of GV in solid organ transplantation, there are limited data with respect to chronic rejection and GV in the realm of VCA. Nevertheless, recent reports from long-term VCA recipients suggest that GV could truly jeopardize allografts in the follow-up evaluation. Chronic rejection and GV include different entities and might have different pathways in distinct organs. Herein, we reviewed the current literature on vascular changes during both acute and chronic allograft rejection, with a focus on their clinical and translational significance for VCA.


Assuntos
Aloenxertos Compostos/irrigação sanguínea , Rejeição de Enxerto/etiologia , Alotransplante de Tecidos Compostos Vascularizados/efeitos adversos , Doença Aguda , Animais , Doença Crônica , Aloenxertos Compostos/imunologia , Transplante de Face/efeitos adversos , Rejeição de Enxerto/imunologia , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Transplante de Mão/efeitos adversos , Humanos , Imunossupressores/uso terapêutico , Fatores de Risco , Fatores de Tempo , Resultado do Tratamento
15.
Am Surg ; 85(6): 631-637, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-31267905

RESUMO

The field of vascularized composite allotransplantation (VCA) has moved from a highly experimental procedure to, at least for some patients, one of the best treatment alternatives for catastrophic tissue loss or dysfunction. Although the worldwide experience is still limited, progress has been made in translation to the clinic, and hand transplantation was recently designated standard of care and is now covered in full by the British Health System. This progress is tempered by the long-term challenges of systemic immunosuppression, and the rapidly evolving indications for VCA such as urogenital transplantation. This update will cover the state of and recent changes in the field, and an update of the Louisville VCA program as our initial recipient, the first person to receive a hand transplant in the United States celebrates the 20th anniversary of his transplant. The achievements and complications encountered over the last two decades will be reviewed. In addition, potential directions for research and collaboration as well as practical issues of how third party payers and funding are affecting growth of the field are presented.


Assuntos
Imunossupressores/administração & dosagem , Procedimentos Cirúrgicos Reconstrutivos/métodos , Alotransplante de Tecidos Compostos Vascularizados/métodos , Feminino , Rejeição de Enxerto , Sobrevivência de Enxerto , Humanos , Masculino , Cuidados Pós-Operatórios/métodos , Complicações Pós-Operatórias/epidemiologia , Complicações Pós-Operatórias/fisiopatologia , Prognóstico , Sociedades Médicas , Imunologia de Transplantes/fisiologia , Alotransplante de Tecidos Compostos Vascularizados/efeitos adversos
16.
Pediatr Transplant ; 23(5): e13466, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31081211

RESUMO

Listing the world's first pediatric bilateral hand transplant patient for a donor posed many challenges including matching the appropriate donor age, bone size, skin tone, and growth potential in an already limited donor population. This study describes the prevalence and distribution of potential pediatric VCA donors in the United States. We assessed the UNOS database from 2008 to 2015 to identify the prevalence of potential pediatric VCA donors. Standard VCA inclusion and exclusion criteria were applied to the dataset for all pediatric solid organ donors. Frequency analyses were performed of characteristics important for VCA matching. The dataset began with 57 300 brain-dead donors and after applying the inclusion and exclusion criteria including age <18, decreased to 4663 (8.1%). The number of pediatric potential VCA donors per UNOS region ranged from 11 to 112/year. The majority of pediatric potential VCA donors were blood type O Whites, with the least common profile being blood type AB of "other" ethnicity. The present study confirmed that pediatric VCA donors are rare and may require longer travel times for procurement and listing at multiple centers in order to find a suitable donor. This will be a limiting factor for the expansion of pediatric VCA.


Assuntos
Mãos/cirurgia , Doadores de Tecidos/provisão & distribução , Alotransplante de Tecidos Compostos Vascularizados , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Estados Unidos
17.
J Vis Exp ; (146)2019 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-31081823

RESUMO

Vascularized composite allotransplantation (VCA) is a relatively new field in the reconstructive surgery. Clinical achievements in human VCA include hand and face transplants and, more recently, abdominal wall, uterus, and urogenital transplants. Functional outcomes have exceeded initial expectations, and most recipients enjoy an improved quality of life. However, as clinical experience accumulates, chronic rejection and complications from the immunosuppression must be addressed. In many cases where grafts have failed, the causative pathology has been ischemic vasculopathy. The biological mechanisms of the acute and chronic rejection associated with VCA, especially ischemic vasculopathy, are important areas of research. However, due to the very small number of VCA patients, the evaluation of proposed mechanisms is better addressed in an experimental model. Multiple groups have used animal models to address some of the relevant unsolved questions in VCA rejection and vasculopathy. Several model designs involving a variety of species are described in the literature. Here we present a reproducible model of VCA heterotopic hindlimb osteomyocutaneous flap in the rat that can be utilized for translational VCA research. This model allows for the serial evaluation of the graft, including biopsies and different imaging modalities, while maintaining a low level of morbidity.


Assuntos
Coristoma/cirurgia , Membro Posterior/cirurgia , Retalhos Cirúrgicos , Pesquisa Médica Translacional , Animais , Membro Posterior/transplante , Modelos Animais , Ratos , Transplante Homólogo , Alotransplante de Tecidos Compostos Vascularizados/métodos
18.
Plast Reconstr Surg ; 143(6): 1688-1701, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31136485

RESUMO

BACKGROUND: Upper limb loss is a devastating condition with dramatic physical, psychological, financial, and social consequences. Improvements in the fields of prosthetics and vascularized composite allotransplantation have opened exciting new frontiers for treatment and rehabilitation following upper limb loss. Each modality offers a unique set of advantages and limitations with regard to the restoration of hand function following amputation. METHODS: Presented in this article is a discussion outlining the complex considerations and decisions encountered when determining patient appropriateness for either prosthetic rehabilitation or vascularized composite allotransplantation following upper limb loss. In this review, the authors examine how psychosocial factors, nature of injury, rehabilitation course, functional outcomes, and risks and benefits may affect overall patient selection for either rehabilitative approach. RESULTS: This review summarizes the current state of the literature. Advancements in both prosthetic and biological strategies demonstrate promise with regard to facilitating rehabilitation following upper limb loss. However, there remains a dearth of research directly comparing outcomes in prosthetic rehabilitation to that following upper extremity transplantation. CONCLUSIONS: Few studies have performed a direct comparison between patients undergoing vascularized composite allotransplantation and those undergoing prosthetic rehabilitation. Upper extremity transplantation and prosthetic reconstruction should not be viewed as competing options, but rather as two treatment modalities with different risk-to-benefit profiles and indications.


Assuntos
Amputação/reabilitação , Amputados/reabilitação , Membros Artificiais , Qualidade de Vida , Extremidade Superior/cirurgia , Alotransplante de Tecidos Compostos Vascularizados/métodos , Amputação/métodos , Amputados/psicologia , Tomada de Decisões , Feminino , Seguimentos , Humanos , Masculino , Seleção de Pacientes , Ajuste de Prótese , Medição de Risco , Resultado do Tratamento
19.
Ann Plast Surg ; 82(5): 574-576, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30985343

RESUMO

Until, sometime ago, microsurgery meant mainly covering a defect or replanting severed parts back to where they belong. Now, restoration of original function and aesthetic consideration is a must in planning reconstructive procedure. Hand transplant combines hand surgery and microsurgery with complex multidisciplinary care.At the anniversary of our first cadaveric bilateral proximal forearm transplantation done in the country's government institute, we would like to share our experience in performing the surgery, outcomes so far, complications, and lessons learned, to contribute to the growing knowledge of vascularized composite allotransplant.


Assuntos
Queimaduras por Corrente Elétrica/cirurgia , Antebraço/cirurgia , Alotransplante de Tecidos Compostos Vascularizados/métodos , Adolescente , Amputação , Cadáver , Humanos , Masculino
20.
Plast Reconstr Surg ; 143(5): 1074e-1080e, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31033834

RESUMO

Vascularized composite allotransplantation is the ultimate reconstructive tool when no other means of reconstruction are available. Despite its immense potential, the applicability of vascularized composite allotransplantation is hampered by high rejection rates and the requirement for high doses of immunosuppressive drugs that are associated with severe adverse effects and death. Because this is a non-life-saving procedure, widespread use of vascularized composite allotransplantation demands methods that will allow the reduction or elimination of immunosuppressive therapy. Efficient methods for the cryopreservation of biological cells and tissues have been sought for decades. The primary challenge in the preservation of viable tissue in a frozen state is the formation of intracellular and extracellular ice crystals during both freezing and thawing, which cause irreversible damage to the tissue. Recent proof-of-concept transplantations of a complete cryopreserved and thawed hindlimb in a rat model have demonstrated the potential of such methods. In the current review, the authors discuss how limb cryopreservation can attenuate or eliminate allograft rejection by either enabling better human leukocyte antigen matching or by adaptation of clinical tolerance protocols such as mixed chimerism induction. Also, the authors discuss the possible advantages of cryopreservation in autologous tissue salvage and cryopreservation following trauma. Clinical-grade cryopreservation may revolutionize the field of reconstruction, organ banking, and complex traumatic limb injury management.


Assuntos
Aloenxertos Compostos , Criopreservação/métodos , Extremidades/lesões , Preservação de Órgãos/métodos , Alotransplante de Tecidos Compostos Vascularizados/métodos , Animais , Extremidades/transplante , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Humanos , Modelos Animais , Ratos , Bancos de Tecidos , Transplante Homólogo , Alotransplante de Tecidos Compostos Vascularizados/efeitos adversos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA