Xenotransplantation: a consistent perspective / Xenotransplante: uma perspectiva consistente

ABSTRACT Are presented results of experimental pig kidney xenotransplantation in Brazil, which aims to reduce the waiting list mortality due to shortage of organs. Recent clinical results obtained abroad are commented.

RESUMO Apresentam-se resultados de xenotransplante suíno de rim experimental no Brasil que visa reduzir as listas de espera nas quais falecem muitos inscritos à espera do transplante. Comentam-se os recentes resultados clínicos obtidos no exterior.

Human islet xenotransplantation in rodents: A literature review of experimental model trends

Among the innovations for the treatment of type 1 diabetes, islet transplantation is a less invasive method of treatment, although it is still in development. One of the greatest barriers to this technique is the low number of pancreas donors and the low number of pancreases that are available for transplantation. Rodent models have been chosen in most studies of islet rejection and type 1 diabetes prevention to evaluate the quality and function of isolated human islets and to identify alternative solutions to the problem of islet scarcity. The purpose of this study is to conduct a review of islet xenotransplantation experiments from humans to rodents, to organize and analyze the parameters of these experiments, to describe trends in experimental modeling and to assess the viability of this procedure. In this study, we reviewed recently published research regarding islet xenotransplantation from humans to rodents, and we summarized the findings and organized the relevant data. The included studies were recent reports that involved xenotransplantation using human islets in a rodent model. We excluded the studies that related to isotransplantation, autotransplantation and allotransplantation. A total of 34 studies that related to xenotransplantation were selected for review based on their relevance and current data. Advances in the use of different graft sites may overcome autoimmunity and rejection after transplantation, which may solve the problem of the scarcity of islet donors in patients with type 1 diabetes.

Successful Xenograft of Endoscopic Ultrasound-Guided Fine-Needle Aspiration Specimen from Human Extrahepatic Cholangiocarcinoma into an Immunodeficient Mouse

Patient-derived tumor xenograft is the transfer of primary human tumors directly into an immunodeficient mouse. Patient-derived tumor xenograft plays an important role in the development and evaluation of new chemotherapeutic agents. We succeeded in generating a patient-derived tumor xenograft of a biliary tumor obtained by endoscopic ultrasound-guided fine-needle aspiration from a patient who had an inoperable extrahepatic cholangiocarcinoma. This patient-derived tumor xenograft will be a promising tool for individualized cancer therapy and can be used in developing new chemotherapeutic agents for the treatment of biliary cancer in the future.

Development of dog mammary tumor xenograft in immunosuppressed Swiss albino mice.

Development and study of dog mammary tumour xenograft in immunosuppressed Swiss Albino Mice adds a new dimension in cancer research as dog tumors have many similarities with human tumors regarding progression, histopathology, molecular mechanism, immune response and therapy. Failure of the immune system to recognize and eliminate cancer cells leads to cancer progression and the fight between immune cells and cancer cells has a great role in understanding the mechanism of cancer progression and elimination. Rejection and acceptance of tumour xenograft depends on efficiency of CD4+, CD8+ and NK cell populations. In the present investigation, dog mammary tumor xenograft in cyclosporine-A and γ-irradiated, immunosuppressed Swiss Albino mice was developed and the immune cell status of graft accepted and rejected mice was assessed. It was observed that all the major immune cells (CD4+, CD8+ and NK cells) play an equal role in tumour rejection.

Evaluation of a canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds in an abdominal full-thickness resection model of growing rats

We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) compared to a those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue while promoting cell migration and supporting tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension. Canine SIS was obtained from donor German shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy (SEM). A 2.50-cm2 section of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague-Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were histopathologically examined and tensile load was tested. One month after surgery, CD68+ macrophage numbers in the SIS group were increased, but the number of CD8+ T cells in this group declined more rapidly than that in rats treated with the mesh. In the SIS group, few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers were observed. No significant differences in the tensile load test results were found between the SIS and mesh groups at 24 weeks. Canine SIS may therefore be a suitable replacement for artificial biological scaffolds in small animals.

Tumor odontogenico queratoquistico: tratamiento conservador con injerto autologo combinado con plasma rico en plaquetas / Queratoquistico odontogenic tumor: conservative treatment combined with autologous platelet rich plasma

Muchos autores consideran que el origen del tumor Odontogénico Queratoquístico, es la lámina dental, otros autores lo asocian al órgano del esmalte. Éste es el segundo tumor odontogénico más común, considerado el más agresivo y con el mayor porcentaje de recidiva. En la década de los años 90, algunos investigadores propusieron entre las alternativas de tratamiento del tumor, el utilizar como coadyuvante en la reparación y cicatrización ósea, el gel de plasma rico en plaquetas más injertos óseos; con el objetivo de promover una maduración más rápida y una cicatrización óptima de los defectos óseos producto del curetaje. Se reporta un caso clínico de un paciente de sexo femenino, 35 años de edad, el cual es remitido, por presentar lesión radiolúcida extensa en zona de mentón, que compromete órganos dentarios 35 y 45. Se realiza punción aspirativa, obteniendo un contenido seroso con trazos sanguinolentos, que en conjunto con la biopsia incisional confirman el diagnóstico de tumor odontogénico queratoquístico. Se decidió realizar enucleación y curetaje óseo amplio del lecho quirúrgico, colocación de injerto heterólogo y autólogo, este último, obtenido de rama ascendente mandibular, combinado con gel de plasma rico en plaquetas con fines de regeneración ósea, posteriormente controles clínicos y radiográficos durante un año.

Many authors believe that the origin of the keratocysts Odontogenic Tumor is the dental lamina, others authors associate it with the enamel organ. This is the second most common odontogenic tumor, considered the most aggressive, with the highest rate of recurrence. During the 90´s, some researchers suggested the alternative treatment of the Tumor, using as an adjunct in the repair and bone healing, the gel of plasma rich in platelets plus bone grafts, to promote a more rapid maturation and an optimal healing of bone defects of the product curettage. It is reported a case of a female patient, 35 years old, which is transmitted by introducing large radiolucent lesion in the chin area, involving from tooth 35 to 45 in extension. Puncture aspiration is performed, obtaining a substance with serous bloody strokes, which together with the incisional biopsy confirmed the diagnosis of Tumor Odontogenic Keratocysts. It was decided to perform enucleation and bone curettage comprehensive surgical placement of autologous and heterologous graft, this latter obtained from the mandibular ramus, gel combined with platelet-rich plasma for bone regeneration, clinical and radiographic controls after one year.

A murine model of xenotransplantation of human glioblastoma with imunosupression by orogastric cyclosporin / Modelo murino de xenotransplante de glioblastoma humano com imunossupressão utilizando ciclosporina orogástrica

Several animal experimental models have been used in the study of malignant gliomas. The objective of the study was to test the efficacy of a simple, reproducible and low cost animal model, using human cells of glioblastoma multiforme (GBM) xenotransplantated in subcutaneous tissue of Wistar rats, immunosuppressed with cyclosporin given by orogastric administration, controlled by nonimunosuppressed rats. The animals were sacrificed at weekly intervals and we have observed gradual growth of tumor in the immunosuppressed group. The average tumor volume throughout the experiment was 4.38 cm³ in the immunosuppressed group, and 0.27 cm³ in the control one (p<0.001). Tumors showed histopathological hallmarks of GBM and retained its glial identity verified by GFAP and vimentin immunoreaction. Immunosuppression of rats with cyclosporin was efficient in allowing the development of human glioblastoma cells in subcutaneous tissues. The model has demonstrated the maintenance of most of the histopathological characteristics of human glioblastoma in an heterotopic site and might by considered in research of molecular and proliferative pathways of malignant gliomas.

Vários modelos animais têm sido avaliados no estudo dos gliomas e até o momento nenhum pôde ser considerado ideal. O objetivo deste trabalho é verificar a eficácia de um modelo animal simples, reprodutível e de baixo custo. Utilizamos células humanas de glioblastoma multiforme (GBM) xenotransplantadas em ratos Wistar, submetidos a imunossupressão com ciclosporina administrada por via orogástrica. Células tumorais foram implantadas no tecido subcutâneo dos ratos imunossuprimidos com ciclosporina, sendo o controle feito em ratos não imunossuprimidos. Os animais foram sacrificados em intervalos semanais e foi observado crescimento progressivo do tumor no grupo imunossuprimido. A média do volume tumoral em todo o experimento foi de 4,38 cm³ no grupo imunossuprimido e 0,27 cm³ no grupo controle (p<0,001). Os tumores apresentavam características histopatológica do GBM e mantinham sua identidade glial, verificadas por imunoreação para GFAP e vimentina. A imunossupressão dos ratos com ciclosporina foi eficiente em permitir o desenvolvimento do glioblastoma no tecido subcutâneo. Uma vez que o presente modelo mantém a maioria das características histopatológicas do glioblastoma humano, ele pode ser considerado em estudos que avaliem as vias moleculares e proliferativas dos gliomas malignos.

64-Channel multi-detector row CT angiographic evaluation of the micropigs for potential living donor lung transplantation

Micropigs are the most likely source animals for xenotransplantation. However, an appropriate method for evaluating the lung of micropigs had not been established. Therefore, this study was performed to evaluate the feasibility of 64-channel multi-detector row computed tomography (MDCT) to measure the diameter of the pulmonary arteries and the lung volume in micropigs. The mean diameters of the trachea, and left and right bronchi were 1.6 +/- 0.17, 1.18 +/- 0.14, and 1.1 +/- 0.11 cm, respectively. The mean diameters of the main, right, and left pulmonary arteries were 1.38 +/- 0.09, 1.07 +/- 0.26, and 0.98 +/- 0.13 cm and the diameters of right, left, and common inferior pulmonary veins were 0.97 +/- 0.20, 0.76 +/- 0.20, and 1.99 +/- 0.26 cm, respectively. The mean lung volume was 820.3 +/- 77.11 mL. The data presented in this study suggest that the MDCT may be a noninvasive, rapid, and accurate investigational method for pulmonary anatomy in living lung donors.

Corporoplasty using bovine pericardium grafts in complex penile prosthesis implantation surgery

Purpose: This paper is the first, to our knowledge, to propose the use of a bovine pericardium graft in corporoplasty for penile prosthesis implantation. The advantages of bovine pericardium graft have been demonstrated by its use in cardiac surgery, including low cost, biocompatibility, impermeability, resistance to dilatation, flexibility, low likelihood of retraction, absence of antigenic reaction and natural absorption of the tissue. In this paper, we propose the use of this heterologous material graft in corporoplasty for penile prosthesis implantation. Materials and Methods: Five patients with a history of erosion, infection and fibrosis, mean time of follow-up 32 months (range 9-48 months). Bovine pericardium was used to cover large areas of implanted penile prostheses when use of the tunica albuginea was unfeasible. Results: The surgical procedure resulted in no complications in all patients. Conclusions: Bovine pericardium may substitute synthetic and autologous material with the additional advantages of lower cost and greater availability.

Imaging evaluation of the liver using multi-detector row computed tomography in micropigs as potential living liver donors

The shortage of organ donors has stimulated interest in the possibility of using animal organs for transplantation into humans. In addition, pigs are now considered to be the most likely source animals for human xenotransplantation because of their advantages over non-human primates. However, the appropriate standard values for estimations of the liver of micropigs have not been established. The determination of standard values for the micropig liver using multi-detector row computed tomography (MDCT) would help to select a suitable donor for an individual patient, determine the condition of the liver of the micropigs and help predict patient prognosis. Therefore, we determined the standard values for the livers of micropigs using MDCT. The liver parenchyma showed homogenous enhancement and had no space-occupying lesions. The total and right lobe volumes of the liver were 698.57 +/- 47.81 ml and 420.14 +/- 26.70 ml, which are 51.74% and 49.35% of the human liver volume, respectively. In micropigs, the percentage of liver volume to body weight was approximately 2.05%. The diameters of the common hepatic artery and proper hepatic artery were 6.24 +/- 0.20 mm and 4.68 +/- 0.13 mm, respectively. The hepatic vascular system of the micropigs was similar to that of humans, except for the variation in the length of the proper hepatic artery. In addition, the diameter of the portal vein was 11.27 +/- 0.38 mm. In conclusion, imaging evaluation using the MDCT was a reliable method for liver evaluation and its vascular anatomy for xenotransplantation using micropigs.

Islet transplantation: the quest for an ideal source

The progress of islet transplantation as a new therapy for patients with diabetes mellitus depends directly upon the development of efficient and practical immunoisolation methods for the supply of sufficient quantities of islet cells. Without these methods, large scale clinical application of this therapy would be impossible. Two eras of advances can be identified in the development of islet transplantation. The first was an era of experimental animal and human research that centered on islet isolation procedures and transplantation in different species as evidence that transplanted islets have the capability to reverse diabetes. The second was the era of the Edmonton protocol, when the focus became the standardization of isolation procedures and introduction of new immunosuppressive drugs to maintain human allograft transplantation. The quest for an alternative source for islets [xenographs, stem cells and cell cultures] to overcome the shortage of human islets was an important issue during these eras. This paper reviews the history of islet transplantation and the current procedures in human allotransplantation, as well as different types of immunoisolation methods. It explores novel approaches to enhancing transplantation site vascularity and islet cell function, whereby future immunoisolation technology could offer additional therapeutic advantages to human islet allotransplantation

Aspectos clínicos e radiográficos do pericárdio bovino como substituto do ligamento cruzado cranial de cães / Clinical and radiographic aspects of the bovine pericardium as a substitute of the canine cranial cruciate ligament

Avaliaram-se os aspectos clínicos e radiográficos do enxerto de pericárdio bovino, preservado em glicerina, como substituto do ligamento cruzado cranial. Quinze cães machos, sem raça definida, pesando entre 17,4 e 31,6 kg, foram submetidos à ruptura experimental do ligamento cruzado cranial e à substituição por pericárdio, via videoartroscopia. Os cães foram divididos em três grupos de cinco e avaliados aos 30, 90 e 120 dias. O membro operado foi imobilizado por duas semanas e procederam-se avaliações clínicas semanais. Radiografias foram feitas mensalmente e foram realizadas colheita de líquido sinovial nos tempos descritos. Clinicamente, os cães mostraram claudicação acentuada a moderada, hipotrofia muscular no membro operado e acentuado deslocamento cranial da tíbia em relação ao fêmur. As alterações degenerativas foram observadas nas radiografias. Observou-se instabilidade acentuada em todos os animais. O líquido sinovial tinha características de inflamação. Concluiu-se que o enxerto rompeu precocemente, provocou reação inflamatória persistente e fenômenos de rejeição, não sendo, portanto, recomendado para substituição do ligamento cruzado cranial de cães

The clinical and radiographic aspects of the bovine pericardium preserved in glicerin, were evaluated as a substitute for canine cranial cruciate ligament. Fifteen male mongrel dogs weighing between 17.4 and 31.6kg had the ligament experimentally ruptured and the stifle joint stabilized by an arthroscopical technique with bovine pericardium as a graft. The dogs were divided into three groups of five animals each. They were evaluated at 30, 90 and 120 days. The operated limb was imobillized for two weeks and clinical examination was performed weekly. Radiographs were taken monthly and the sinovial fluid was collect at 30, 90 and 120 days. Clinically, dogs presented high to moderate lameness, muscle hipotrophy in the operated limb and accentuated cranial drawer movement. Degenerative disease was detected in radiography. All dogs showed total rupture of the graft. Sinovial fluid analysis showed characteristics of inflammation. It can be concluded that pericardium graft failed prematurely, incited persistent inflammatory reaction and rejection phenomena. Thus, it cannot be recommended as a xenograft for cranial cruciate ligament replacement

Avaliação da resposta tecidual ao implante de osso bovino misto medular em subcutâneo de ratos / Evaluation of tissue repair, in case of bovine bone implantation mixed with bone marrow graft, in subcutaneous region of rats

O objetivo deste trabalho foi avaliar a resposta tecidual ao implante do osso bovino misto (OBM) acelular em subcutâneo de ratos. Blocos de OBM (10x10x5mm) foram implantados no tecido subcutâneo de 25 ratos machos Wistar, os quais foram mortos após 3, 7, 14, 30 e 60 dias (n = 5/período) da cirurgia. O tecido reacional foi coletado, fixado em formol 10% tamponado, lavado, desidratado, diafanizado em xilol e incluído em parafina. Cortes com 6µm de espessura foram corados com Hematoxilina e Eosina. A análise microscópica subjetiva indicou que o OBM foi circundado por tecido de granulação (composto de células mononucleares semelhantes a fibroblastos e polimorfonucleares) aos 3 dias. Entre 7 e 30 dias observou-se a invasão gradual dos poros do material implantado pelo tecido de granulação apresentando um discreto infiltrado inflamatório mononuclear com poucas células gigantes multinucleadas (CGM). Concomitantemente à angiogênese observa-se aparecimento de adipócitos no interior do material confirmando porosidade interconectada dos poros. Após 60 dias os espaços medulares estavam completamente ocupados por tecido de granulação composto por células semelhantes a fibroblastos e raras células inflamatórias mononucleares e CGM. Não se observou indícios de degradação ou absorção do material até o período de 60 dias. Considerando a ausência de necrose ou outros sinais de destruição tecidual, a presença de proliferação celular e angiogênese para o interior do material e que não se observou absorção do material, concluiu-se que o OBM é biocompatível e não absorvível, tendo potencial aplicação na engenharia de tecidos.

The aim of this study was to evaluate the tissue response to acellular mixed bovine bone graft (MBG) implanted in the subcutaneous tissue of rats. MBG in block (10x10x5mm) was implanted in 25 adult male Wistar rats, killed 3, 7, 14, 30 e 60 days after surgery (n=5/period). The granulation tissue was fixed in 10% buffered formalin, washed, dehydrated in ethanol, diafanized in xylene, and included in paraffin according to standard technique. Histological sections measuring 6µm in thickness were stained with haematoxylin and eosin. Histological analysis 3 days after surgery showed a granulation tissue around the MGB block presenting mononuclear cells like fibroblasts and neutrophils. From 7 to 30 days, chronic inflammatory infiltrate consisting mainly of macrophages and few infl ammatory multinucleated giant cells (MGC) were observed invading the porous of MGB. Parallel to angiogenesis, adipocytes were present in the interior of material, corroborating the presence of interconnected porous. After 60 days, medullar spaces were fulfilled with granulation tissue presenting fibroblast-like cells and rare mononuclear inflammatory cells and MGC. No signs of material degradation or absorption were noted throughout the experimental periods. Considering the absence of necrosis or other signs of tissue destruction, cell growth and angiogenesis inside the material and the absence of material absorption, it was concluded that MGB was biocompatible and non absorbable being potentially adequate for tissue engineering.

Modified Acellularization for Successful Vascular Xenotransplantation

The purpose of this study was to estimate the possibilities of an acellular matrix using a modified acellularization protocol, which circumvents immunological, microbiological, and physiological barriers. We treated porcine subclavian arteries with various reagents to construct acellular grafts. Afterwards, these grafts were interposed in a mongrel dogs' abdominal aorta. Six dogs underwent interposition with fresh porcine grafts (control group), and seven had interposed acellular grafts (acellular group). The control and acellular group dogs were sacrificed at 1, 3, 5 (n=2 in each group) and 12 months (n=1 in acellular group) after the operation. Histopathological examinations were then performed, to assess the degree to which re-endothelialization, inflammation, thrombus formation, and calcification occurred. The entire acellular group, but none of the control group, exhibited re-endothelialization. The degrees to which inflammation, thrombosis, and calcification occurred were found to be lower in the acellular group. We also discovered many smooth muscle cells in the medial layer of the xenograft that had been implanted in the dog sacrificed 12 months after the operation. These results suggest that the construction of xenografts using our modified acellularization protocol may offer acceptable outcomes as a vascular xenograft.

Mistura de proteínas morfogenéticas ósseas, hidroxiapatita, osso inorgânico e colágeno envolta por membrana de pericárdio no preenchimento de defeito ósseo segmentar em coelhos / Mixture of bone morphogenetic protein, hydroxyapatite, inorganic bone and collagen interposed by pericardium barrier membrane in the filling of the segmental bone defect in rabbits

Avaliou-se o uso de biomaterial de origem bovina na regeneração de defeitos ósseos segmentares empregando-se 12 coelhos, fêmeas, da raça Norfolk, com idade de seis meses e pesos entre 3 e 4,5kg. Realizou-se falha segmentar bilateral de um centímetro de comprimento na diáfise do rádio, com inclusão do periósteo. No membro direito, o defeito foi delimitado por membrana de pericárdio liofilizada, contendo em seu interior mistura de proteínas morfogenéticas ósseas adsorvidas a hidroxiapatita, colágeno liofilizado e osso inorgânico. No membro esquerdo, o defeito não recebeu tratamento. Radiografias foram obtidas ao término do procedimento cirúrgico e aos sete, 30, 60, 90, 120 e 150 dias de pós-operatório. Após eutanásia de seis coelhos aos 60 dias e seis aos 150 dias de pós-cirúrgico, os resultados radiográficos e histológicos mostraram que a regeneração óssea foi inibida nos defeitos segmentares tratados com o biomaterial.

Biomaterials of bovine origin in regenerating segmental bone defects were evaluated. Twelve six-month old Norfolk rabbits, weighting 3 to 4.5kg were used. A 1cm long segmental defect was created in the radial diaphysis, including the periosteum, of both forelimbs. In the right forelimb, the defect was filled using a mixture of bone morphogenic proteins adsorbed to hydroxyapatite, agglutinant of lyophilized collagen in granules and anorganic cortical bone in granules delimited by a pericardial membrane. In the left forelimb, the defect did not receive treatment and served as a control. Radiographies were taken immediately after surgery and at seven, 30, 60, 90, 120 and 150 days post-operatively. Six rabbits were euthanized at 60 days and the other six at 150 days post-surgery for histological evaluation. Radiographic and histological results revealed that bone regeneration was inhibited in the segmental defects receiving biomaterials.

Keloid heterograft in the hamster (mesocricetus auratus) cheek pouch

OBJETIVO: Investigar a integração do transplante heterólogo de quelóide na bolsa jugal do hamster (Mesocricetus auratus). MÉTODOS: A amostragem consiste de 18 hamsters machos, heterogênicos, com 10 a 14 semanas de idade. Fragmentos de quelóide foram obtidos de cicatrizes queloidianas da região mamária de paciente adulta parda. Cada hamster foi enxertado em ambas as bolsas com fragmentos de quelóide, totalizando 36 fragmentos enxertados. Os animais foram distribuídos em 6 grupos para exame dos fragmentos enxertados, com 5, 12, 21, 42, 84 e 168 dias. Uma avaliação macroscópica é realizada comparando a bolsa contendo o fragmento enxertado em cada período com a mesma bolsa no pós-operatório imediato, mediante a comparação de fotografias padronizadas. À microscopia, considera-se a presença de vasos sangüíneos no tecido conjuntivo do fragmento enxertado como critério de integração do mesmo. Outros eventos, como secreção de queratina, presença de infiltrados celulares e aspecto do epitélio e das fibras colágenas do quelóide, também são observados. RESULTADOS: A macroscopia revela intensa vascularização na bolsa até 12 dias de enxertia, e a presença constante de pigmentação castanho-escura nos fragmentos de quelóide enxertados. Na microscopia constata-se a integração dos fragmentos de quelóide pela presença de capilares sangüíneos no tecido conjuntivo. Observa-se, também, a presença de intenso infiltrado celular do tipo inflamatório até 12 dias, a permanência do epitélio do quelóide até 21 dias, e o aparecimento de melanócitos a partir de 42 dias. CONCLUSÃO: A bolsa jugal do hamster representa, a priori, modelo experimental para investigação do quelóide.

Experimental model of cultured skin graft

Um dos modelos animais mais utilizados de auto-enxertia de queratinócitos cultivados é baseado em xeno-enxerto de queratinócitos humanos em rato atímico, um receptor imunologicamente neutro que atua como carreador biológico. Muitos fatos podem ser estudados nesse modelo que acontecem após o transplante sem os aspectos éticos do estudo clínico. A proposição do modelo experimental esta relacionada a sequência do transplante de pele parcial ou total como auto-enxerto ou xeno-enxerto, cultivado ou não, no dorso do rato atímico. O modelo apresenta a possibilidade do estudo in vivo do animal atímico, quando o estudo in vivo em anima nobili não é considerado ético. Isso permite a avaliação do xeno-enxerto de células humanas normais ou modificadas geneticamente modificadas cultivadas e a associação de células cultivadas e substitutes dérmicos, de enxertos compostos e de auto-enxerto.

Experimental model in hamster (Mesocricetus auratus) to study heterologous graft of scars and cutaneous diseases in plastic surgery

O hamster sírio dourado (Mesocricetus auratus) possui no subepitélio de suas bolsas jugais um "Local de Privilégio Imunológico", permitindo a integração de homo e heteroenxertos. Este artigo descreve as características anatômicas e histológicas desse local, assim como os aspectos relativos as suas propriedades imunológicas. Cita, também, as vantagens desse modelo experimental sobre outros modelos portadores, naturais ou induzidos, de imunodeficiência. Com base nessas vantagens, e também baseado na literatura, tem o intuito de estabelecer esse modelo, mediante a realização de heteroenxertos, como uma outra opção para investigar distúrbios cicatriciais, como o quelóide, e doenças de interesse em Cirurgia Plástica, como lesões cutâneas benignas e neoplasias malignas como carcinomas e melanoma cutâneo. Tece, ainda, considerações sobre perspectivas de aplicações desse modelo, ainda bastante desconhecido entre a classe médica brasileira.