RESUMO
Xenotransplantation offers the potential to meet the critical need for heart and lung transplantation presently constrained by the current human donor organ supply. Much was learned over the past decades regarding gene editing to prevent the immune activation and inflammation that cause early organ injury, and strategies for maintenance of immunosuppression to promote longer-term xenograft survival. However, many scientific questions remain regarding further requirements for genetic modification of donor organs, appropriate contexts for xenotransplantation research (including nonhuman primates, recently deceased humans, and living human recipients), and risk of xenozoonotic disease transmission. Related ethical questions include the appropriate selection of clinical trial participants, challenges with obtaining informed consent, animal rights and welfare considerations, and cost. Research involving recently deceased humans has also emerged as a potentially novel way to understand how xeno-organs will impact the human body. Clinical xenotransplantation and research involving decedents also raise ethical questions and will require consensus regarding regulatory oversight and protocol review. These considerations and the related opportunities for xenotransplantation research were discussed in a workshop sponsored by the National Heart, Lung, and Blood Institute, and are summarized in this meeting report.
Assuntos
Transplante de Coração , Transplante de Pulmão , Transplante Heterólogo , Transplante Heterólogo/ética , Humanos , Transplante de Pulmão/ética , Animais , Estados Unidos , Transplante de Coração/ética , National Heart, Lung, and Blood Institute (U.S.) , Pesquisa Biomédica/ética , Doadores de Tecidos/provisão & distribuição , Doadores de Tecidos/éticaRESUMO
BACKGROUND: Efforts to profile atopic dermatitis (AD) tissues have intensified, yet comprehensive analysis of systemic immune landscapes in severe AD remains crucial. METHODS: Employing single-cell RNA sequencing, we analyzed over 300,000 peripheral blood mononuclear cells from 12 severe AD patients (Eczema area and severity index (EASI) > 21) and six healthy controls. RESULTS: Results revealed significant immune cell shifts in AD patients, including increased Th2 cell abundance, reduced NK cell clusters with compromised cytotoxicity, and correlated Type 2 innate lymphoid cell proportions with disease severity. Moreover, unique monocyte clusters reflecting activated innate immunity emerged in very severe AD (EASI > 30). While overall dendritic cells (DCs) counts decreased, a distinct Th2-priming subset termed "Th2_DC" correlated strongly with disease severity, validated across skin tissue data, and flow cytometry with additional independent severe AD samples. Beyond the recognized role of Th2 adaptive immunity, our findings highlight significant innate immune cell alterations in severe AD, implicating their roles in disease pathogenesis and therapeutic potentials. CONCLUSION: Apart from the widely recognized role of Th2 adaptive immunity in AD pathogenesis, alterations in innate immune cells and impaired cytotoxic cells have also been observed in severe AD. The impact of these alterations on disease pathogenesis and the effectiveness of potential therapeutic targets requires further investigation.
Assuntos
Dermatite Atópica , RNA-Seq , Índice de Gravidade de Doença , Análise de Célula Única , Dermatite Atópica/imunologia , Humanos , Imunidade Inata , Masculino , Células Th2/imunologia , Células Th2/metabolismo , Feminino , Adulto , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Estudos de Casos e Controles , Análise da Expressão Gênica de Célula ÚnicaRESUMO
Porcine islet xenotransplantation has been highlighted as an alternative to allo islet transplantation. Despite the remarkable progress that has been made in porcine-islet pre-clinical studies in nonhuman primates, immunological tolerance to porcine islets has not been achieved to date. Therefore, allo islet transplantation could be required after the failure of porcine islet xenotransplantation. Here, we report the long-term control of diabetes by allogeneic pancreatic islet transplantation in diabetic rhesus monkeys that rejected previously transplanted porcine islets. Four diabetic male rhesus monkeys received the porcine islets and then allo islets (5700-19 000 IEQ/kg) were re-transplanted for a short or long period after the first xeno islet rejection. The recipient monkeys were treated with an immunosuppressive regimen consisting of ATG, humira, and anakinra for induction, and sirolimus and tofacitinib for maintenance therapy. The graft survival days of allo islets in these monkeys were >440, 395, >273, and 127, respectively, similar to that in allo islet transplanted cynomolgus monkeys that received the same immunosuppressive regimen without xeno sensitization. Taken together, it is likely that prior islet xenotransplantation does not affect the survival of subsequent allo islets under clinically applicable immunosuppressants.
Assuntos
Diabetes Mellitus , Transplante das Ilhotas Pancreáticas , Ilhotas Pancreáticas , Piperidinas , Pirimidinas , Masculino , Suínos , Animais , Macaca mulatta , Transplante Heterólogo , Imunossupressores/farmacologia , Imunossupressores/uso terapêutico , Sobrevivência de EnxertoRESUMO
BACKGROUND: Studies on the interaction between tumour-infiltrating immune cells (TIICs) and tumour cells in melanoma arising from congenital melanocytic nevus (CMN) are lacking. OBJECTIVE: The aim of this study was to determine the intratumoral immune landscape of TIICs and tumour cells during invasion and metastasis. METHODS: Tissue specimens were obtained from patients with melanoma originating from CMN. Differential gene expression in melanoma cells and TIICs during invasion and metastasis was determined using spatial transcriptomics. RESULTS: As invasion depth increased, the expression of LGALS3, known to induce tumour-driven immunosuppression, increased in melanoma cells. In T cells, the expression of genes that inhibit T-cell activation increased with increasing invasion depth. In macrophages, the expression of genes related to the anti-inflammatory M2 phenotype was upregulated with increasing invasion depth. Compared to primary tumour cells, melanoma cells in metastatic lesions showed upregulated expression of genes associated with cancer immune evasion, including AXL and EPHA2, which impede T-cell recruitment, and BST2, associated with M2 polarization. Furthermore, T cells showed increased expression of genes related to immunosuppression, and macrophages exhibited increased expression of genes associated with the M2 phenotype. CONCLUSIONS: The interaction between melanomas arising from CMN and TIICs may be important for tumour progression and metastasis.
Assuntos
Melanoma , Nevo Pigmentado , Neoplasias Cutâneas , Humanos , Melanoma/genética , Melanoma/imunologia , Melanoma/patologia , Nevo Pigmentado/genética , Nevo Pigmentado/imunologia , Nevo Pigmentado/patologia , Nevo Pigmentado/metabolismo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/imunologia , Perfilação da Expressão Gênica , Linfócitos do Interstício Tumoral/imunologia , Invasividade Neoplásica , Masculino , Macrófagos/metabolismo , Macrófagos/imunologia , Feminino , Galectina 3/genética , Galectina 3/metabolismo , Linfócitos T/imunologia , Transcriptoma , Receptor Tirosina Quinase Axl , Comunicação Celular , Pessoa de Meia-Idade , Galectinas/genética , Galectinas/metabolismo , Receptor Celular 2 do Vírus da Hepatite A/genética , Receptor Celular 2 do Vírus da Hepatite A/metabolismo , Proteínas SanguíneasRESUMO
This study was performed to improve production efficiency at the level of recipient pig and donor nuclei of transgenic cloned pigs used for xenotransplantation. To generate transgenic pigs, human endothelial protein C receptor (hEPCR) and human thrombomodulin (hTM) genes were introduced using the F2A expression vector into GalT-/-/hCD55+ porcine neonatal ear fibroblasts used as donor cells and cloned embryos were transferred to the sows and gilts. Cloned fetal kidney cells were also used as donor cells for recloning to increase production efficiency. Pregnancy and parturition rates after embryo transfer and preimplantation developmental competence were compared between cloned embryos derived from adult and fetal cells. Significantly higher parturition rates were shown in the group of sows (50.0 vs. 4.1%), natural oestrus (20.8 vs. 0%), and ovulated ovary (16.7 vs. 5.6%) compared with gilt, induced and non-ovulated, respectively (P < 0.05). When using gilts as recipients, final parturitions occurred in only the fetal cell groups and significantly higher blastocyst rates (15.1% vs. 21.3%) were seen (P < 0.05). Additionally, gene expression levels related to pluripotency were significantly higher in the fetal cell group (P < 0.05). In conclusion, sows can be recommended as recipients due to their higher efficiency in the generation of transgenic cloned pigs and cloned fetal cells also can be recommended as donor cells through correct nuclear reprogramming.
Assuntos
Clonagem de Organismos , Técnicas de Transferência Nuclear , Animais , Animais Geneticamente Modificados , Blastocisto , Feminino , Fibroblastos , Gravidez , Sus scrofa , SuínosRESUMO
Porcine islet transplantation is an alternative to allo-islet transplantation. Retransplantation of islets is a routine clinical practice in islet allotransplantation in immunosuppressed recipients and will most likely be required in islet xenotransplantation in immunosuppressed recipients. We examined whether a second infusion of porcine islets could restore normoglycemia and further evaluated the efficacy of a clinically available immunosuppression regimen including anti-thymocyte globulin for induction; belimumab, sirolimus, and tofacitinib for maintenance and adalimumab, anakinra, IVIg, and tocilizumab for inflammation control in a pig to nonhuman primate transplantation setting. Of note, all nonhuman primates were normoglycemic after the retransplantation of porcine islets without induction therapy. Graft survival was >100 days for all 3 recipients, and 1 of the 3 monkeys showed insulin independence for >237 days. Serious lymphodepletion was not observed, and rhesus cytomegalovirus reactivation was controlled without any serious adverse effects throughout the observation period in all recipients. These results support the clinical applicability of additional infusions of porcine islets. The maintenance immunosuppression regimen we used could protect the reinfused islets from acute rejection.
Assuntos
Diabetes Mellitus , Transplante das Ilhotas Pancreáticas , Animais , Terapia de Imunossupressão , Macaca mulatta , Suínos , Transplante HeterólogoRESUMO
High mobility group (HMGB1) is an alarmin known to be harmful to pancreatic beta cells and associated with diabetes mellitus pathogenesis and pancreatic islet graft failure. It has been long thought that the suppression of HMGB1 molecule is beneficial to the beta cells. However, recent studies have indicated that cytoplasmic HMGB1 (cHMGB1) could function as a modulator to relieve cells from apoptotic stress by autophagy induction. Particularly, pancreatic beta cells have been known to utilize the autophagy-to-apoptosis switch when exposed to hypoxia or lipotoxicity. This study aimed to investigate the beta cells under hypoxic and lipotoxic stress while utilizing a small molecule inhibitor of HMGB1, inflachromene (ICM) which can suppress cHMGB1 accumulation. It was revealed that under cellular stress, blockade of cHMGB1 accumulation decreased the viability of islet grafts, primary islets and MIN6 cells. MIN6 cells under cHMGB1 blockade along with lipotoxic stress showed decreased autophagic flux and increased apoptosis. Moreover, cHMGB1 blockade in HFD-fed mice produced unfavorable outcomes on their glucose tolerance. In sum, these results suggested the role of cHMGB1 within beta cell autophagy/apoptosis checkpoint. Given the importance of autophagy in beta cells under apoptotic stresses, this study might provide further insights regarding HMGB1 and diabetes.
Assuntos
Proteína HMGB1/antagonistas & inibidores , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Hipóxia Celular , Sobrevivência Celular/efeitos dos fármacos , Proteína HMGB1/metabolismo , Células Secretoras de Insulina/metabolismo , Células Secretoras de Insulina/transplante , Masculino , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , SuínosRESUMO
PURPOSE OF REVIEW: Porcine islet xenotransplantation is a promising alternative to overcome the shortage of organ donors. For the successful application of islet xenotransplantation, robust immune/inflammatory responses against porcine islets should be thoroughly controlled. Over the last few decades, there have been numerous attempts to surmount xenogeneic immune barriers. In this review, we summarize the current progress in immunomodulatory therapy for the clinical application of porcine islet xenotransplantation. RECENT FINDINGS: Long-term graft survival of porcine islets was achieved by using anti-CD154 Ab-based regimens in a preclinical non-human primate (NHP) model. However, owing to a serious complication of thromboembolism in clinical trials, the development of an anti-CD154 Ab-sparing immunosuppressant procedure is required. The efficacy of new immunosuppressive practices that employ anti-CD40 Abs or other immunosuppressive reagents has been tested in a NHP model to realize their utility in porcine islet xenotransplantation. The recent progress in the development of immunomodulatory approaches, including the immunosuppressive regimen, which enables long-term graft survival in a pig-to-non-human primate islet xenotransplantation model, with their potential clinical applicability was reviewed.
Assuntos
Transplante das Ilhotas Pancreáticas , Animais , Ligante de CD40 , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Humanos , Imunomodulação , Imunossupressores/uso terapêutico , Suínos , Transplante HeterólogoRESUMO
BACKGROUND: Although pancreatic islet transplantation is becoming an effective therapeutic option for patients with type 1 diabetes (T1D) who suffer from a substantially impaired awareness of hypoglycemia, its application is limited due to the lack of donors. Thus, pig-to-human islet xenotransplantation has been regarded as a promising alternative due to the unlimited number of "donor organs." Long-term xenogeneic islet graft survival in pig-to-non-human primate (NHP) models has mainly been achieved by administering the anti-CD154 mAb-based immunosuppressant regimen. Since the anti-CD154 mAb treatment has been associated with unexpected fatal thromboembolic complications in clinical trials, the establishment of a new immunosuppressant regimen that is able to be directly applied in clinical trials is an urgent need. METHODS: We assessed an immunosuppressant regimen composed of clinically available agents at porcine islet transplantation in consecutive diabetic NHPs. RESULTS: Porcine islet graft survival in consecutive diabetic NHPs (n = 7; >222, >200, 181, 89, 62, 55, and 34 days) without severe adverse events. CONCLUSION: We believe that our study could contribute greatly to the initiation of islet xenotransplantation clinical trials.
Assuntos
Diabetes Mellitus Tipo 1 , Transplante das Ilhotas Pancreáticas , Animais , Diabetes Mellitus Tipo 1/cirurgia , Rejeição de Enxerto/prevenção & controle , Sobrevivência de Enxerto , Humanos , Imunossupressores/farmacologia , Primatas , Suínos , Transplante HeterólogoRESUMO
BACKGROUND: The xenotransplant clinical trial with human subjects seems to be technically feasible, however, it needs the strict regulatory framework from the domestic as well as the international level to make sure the safety of the human subject and the general public. METHODS: The authors reviewed and introduced the current regulations regarding the xenotransplant clinical trial in Korea focusing on the recently stipulated act (Advanced Regenerative Medicine and Biopharmacology Act, ARMBA) and the role of the related government agencies and health institutions. RESULTS AND CONCLUSION: Korea is ready to conduct the xenotransplant clinical trial with human subjects in the current regulatory framework satisfying the requirements of the international guidance. The responsible governmental agencies would collaborate in control the xenotransplant clinical trial under the ARMBA and other related acts and guidance.
Assuntos
Regulamentação Governamental , Transplante Heterólogo/normas , Ensaios Clínicos como Assunto , Humanos , República da CoreiaRESUMO
BACKGROUND: We aimed to investigate (a) the long-term survival of corneal grafts from α1,3-galactosyltransferase gene-knockout miniature (GTKOm) pigs in non-human primates as a primary outcome and (b) the effect of anti-CD20 antibody on the survival of corneal grafts from GTKOm pigs as a secondary outcome. METHODS: Nine rhesus macaques undergoing full-thickness corneal xenotransplantation using GTKOm pigs were systemically administered steroid, basiliximab, intravenous immunoglobulin, and tacrolimus with (CD20 group) or without (control group) anti-CD20 antibody. RESULTS: Graft survival was significantly longer (P = .008) in the CD20 group (>375, >187, >187, >83 days) than control group (165, 91, 72, 55, 37 days). When we compared the graft survival time between older (>7- month-old) and younger (≤7-month-old) aged donor recipients, there was no significant difference. Activated B cells were lower in the CD20 group than control group (P = .026). Aqueous humor complement C3a was increased in the control group at last examination (P = .043) and was higher than that in the CD20 group (P = .014). Anti-αGal IgG/M levels were unchanged in both groups. At last examination, anti-non-Gal IgG was increased in the control group alone (P = .013). CONCLUSIONS: The GTKOm pig corneal graft achieved long-term survival when combined with anti-CD20 antibody treatment. Inhibition of activated B cells and complement is imperative even when using GTKO pig corneas.
Assuntos
Linfócitos B/fisiologia , Transplante de Córnea , Galactosiltransferases/genética , Rejeição de Enxerto/prevenção & controle , Xenoenxertos/fisiologia , Animais , Animais Geneticamente Modificados , Anticorpos Monoclonais/uso terapêutico , Antígenos CD20/imunologia , Técnicas de Inativação de Genes , Sobrevivência de Enxerto , Humanos , Ativação Linfocitária , Primatas , Suínos , Porco Miniatura , Transplante HeterólogoRESUMO
BACKGROUND: Xenogeneic islet transplantation using porcine pancreata has been a promising option for substituting human islet transplantation. Moreover, recent advances in pre-clinical results have put islet xenotransplantation closer to the possibility of clinical application. While preparing for the era of clinical xenotransplantation, developing non-invasive immune monitoring method which could predict the graft fate could benefit the patient. However, there are few reports showing predictive immune parameters associated with the fate of the graft in islet xenotransplantation. METHODS: The absolute number and ratio of T-cell subsets have been measured via flow cytometry from the peripheral blood of 16 rhesus monkeys before and after porcine islet xenotransplantation. The correlation between the graft survival and the absolute number or ratio of T cells was retrospectively analyzed. RESULTS: The ratio of CD4+ versus CD8+ T cells was significantly reduced due to CD8+ effector memory cells' increase. Correlation analyses revealed that CD4+ /CD8+ , CD4+ /CD8+ naïve, CD4+ naïve/CD8+ naïve, and CD4+ central memory/CD8+ naïve cell ratios negatively correlated with the duration of graft survival. Conversely, further analyses discovered strong, positive correlation of CD4+ /CD8+ cell ratios within the early graft-rejected monkeys (≤60 days). CONCLUSIONS: This retrospective study demonstrated that CD4+ /CD8+ ratios correlated with graft survival, especially in recipients which rejected the graft in early post-transplantation periods. CD4+ /CD8+ ratios could be used as a surrogate marker to predict the graft fate in pig-to-NHP islet xenotransplantation.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Rejeição de Enxerto/imunologia , Sobrevivência de Enxerto/imunologia , Transplante Heterólogo , Animais , Xenoenxertos/imunologia , Macaca mulatta , Suínos , Transplante Heterólogo/métodosRESUMO
BACKGROUND: Microsatellite instability (MSI)-high (MSI-H) colorectal cancer is known to be associated with increased tumor-infiltrating lymphocytes (TILs), elevated host systemic immune response, and a favorable prognosis. In gastric cancer, however, MSI status has rarely been evaluated in the context of TILs and systemic immune response. MATERIALS AND METHODS: We evaluated data for 345 patients with gastric cancer who underwent gastrectomy with MSI typing. The numbers of TILs were counted after immunohistochemical staining with anti-CD3, CD4, CD8, forkhead box P3 (Foxp3), and granzyme B to quantify the subsets of TILs. To evaluate the systemic immune response, the differential white blood cell count and prognostic nutritional index (PNI) were obtained. RESULTS: Of the 345 patients, 57 demonstrated MSI-H tumors and 288 demonstrated non-MSI-H tumors. MSI-H tumors carried significantly higher densities of CD8+ T cells, Foxp3+ T cells, and granzyme B+ T cells and a higher ratio of Foxp3/CD4 and granzyme B/CD8. The prognostic impact of TILs differed between patients with MSI-H tumors and those with non-MSI-H tumors. The TIL subsets were not found to be significant prognostic factors for recurrence-free survival (RFS) or overall survival (OS) in the MSI-H tumor group. In the non-MSI-H tumor group, multivariate analysis showed that stage, PNI, and CD4+ T cells were independent prognostic factors for RFS, and stage, PNI, and the Foxp3/CD4 ratio were independent prognostic factors for OS. CONCLUSIONS: The association between systemic/local immune response and prognosis differed according to MSI status. Different tumor characteristics and prognoses according to MSI status could be associated with the immunogenicity caused by microsatellite instability and subsequent host immune response. IMPLICATIONS FOR PRACTICE: This study demonstrates that the density of each subset of tumor-infiltrating lymphocytes (TILs) differed between microsatellite instability (MSI)-high and non-MSI-high tumors. Moreover, the prognostic effect of the preoperative systemic immune response status and TILs differed between the MSI-high (MSI-H) and non-MSI-H tumor groups. The present study may help to identify the mechanisms of cancer progression and develop treatment strategies for MSI-high gastric cancer.
Assuntos
Reparo de Erro de Pareamento de DNA/imunologia , Linfócitos do Interstício Tumoral/imunologia , Instabilidade de Microssatélites , Neoplasias Gástricas/genética , Neoplasias Gástricas/imunologia , Linfócitos T CD8-Positivos/imunologia , Feminino , Humanos , Imunidade Ativa/genética , Imunidade Ativa/imunologia , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Metástase Neoplásica , Estadiamento de Neoplasias , Prognóstico , Neoplasias Gástricas/patologia , Taxa de Sobrevida , Microambiente Tumoral/imunologiaRESUMO
ß-cell deficiency is common feature of type 1 and late-stage of type 2 diabetes mellitus. Thus, ß-cell replacement therapy has been the focus of regenerative medicine past several decades. Particularly, evidences suggest that ß-cell regeneration via transdifferentiation from sources including α-cells is promising. However, data using higher mammals besides rodents are scarce. Here, we examined whether endogenous pancreatic ß-cells could regenerate spontaneously or under normoglycemia following porcine islet transplantation for varied periods up to 1197 days after streptozotocin-induced diabetes, and remaining α-cells transdifferentiate into ß-cells by GABA treatment in vivo and in vitro. The results showed that endogenous ß-cells rarely regenerate in both conditions as evidenced by stagnant serum C-peptide levels and ß-cell number in the pancreas, and the remaining α-cells did not transdifferentiate into ß-cells by GABA treatment. Collectively, we concluded that monkey ß-cells had relatively low regenerative potential compared with rodent counterpart and GABA treatment could not induce α-to-ß-cell transdifferentitation.
Assuntos
Transdiferenciação Celular , Diabetes Mellitus Experimental/patologia , Diabetes Mellitus Tipo 2/patologia , Células Secretoras de Glucagon/patologia , Células Secretoras de Insulina/patologia , Regeneração , Ácido gama-Aminobutírico/farmacologia , Animais , Transdiferenciação Celular/efeitos dos fármacos , Células Secretoras de Glucagon/efeitos dos fármacos , Células Secretoras de Glucagon/metabolismo , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Macaca mulatta , Regeneração/efeitos dos fármacos , SuínosRESUMO
Pancreatic islet transplantation has been known as the best cure for patients suffering from severe type 1 diabetes mellitus (T1DM). Despite meaningful advances in human allogeneic islet transplantation field, significant amounts of islet loss in early post-transplantation periods is still a big concern for clinicians. One of the major factors determining the fate of the islets is the danger-associated molecular patterns (DAMPs) secreted by activated immune cells or islets themselves under hypoxic stress. High mobility group box 1 (HMGB1) protein is one of the best characterized DAMP molecules associated with islets. HMGB1 is known to be passively released by transplanted murine islet cells after taking damages from cytokines, reactive oxygen species, and other DAMPS, and the released HMGB1 harms neighboring islet cells by interacting with receptors expressed on murine islets such as toll-like receptor 2 (TLR2) and TLR4, thereby forming a vicious cycle. Here, we show that a small molecule inhibitor inflachromene (ICM) was capable of blocking the secretion of HMGB1 from murine islet cells during the normoxic and hypoxic post-isolation period. Notably, the treatment of ICM during the islet isolation process resulted in decreased HMGB1 levels during the subsequent cell culture. ICM's in vivo efficacy was evaluated in murine syngeneic islet transplantation model, and it significantly reduced the serum and graft level of HMGB1. Ultimately, the intraperitoneal administration of ICM prevented the loss of marginal-mass islet grafts and reversed the diabetes in mice.
Assuntos
Proteína HMGB1/antagonistas & inibidores , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Ilhotas Pancreáticas/efeitos dos fármacos , Animais , Feminino , Proteína HMGB1/metabolismo , Compostos Heterocíclicos de 4 ou mais Anéis/administração & dosagem , Injeções Intraperitoneais , Ilhotas Pancreáticas/metabolismo , Camundongos , Camundongos Endogâmicos BALB CRESUMO
BACKGROUND: Subcutaneous tissue is an attractive extra-hepatic heterotopic site for islet transplantation; however, poor oxygen tension and blood supply during early engraftment of implanted islets have limited the use of this site in clinical applications. METHODS: This study investigated the vascularization potential of hypoxia-preconditioned mesenchymal stem cells (3% O2 ; hypo-MSCs) in PLGA-based bio-artificial beds for subsequent subcutaneous islet transplantation. Sheet-typed polymeric PLGA scaffolds coated with hypo-MSCs or normo-MSCs (MSCs cultured under normoxia conditions, 21% O2 ) were implanted subcutaneously in mice. RESULTS: Compared to normo-MSCs, hypo-MSCs significantly enhanced vasculogenesis, both on the interior and exterior surfaces of the implanted PLGA devices, which peaked 4 weeks after implantation. Further, infusion of porcine islets inside the prevascularized PLGA bed restored normal glycemic control in 6 of 6 STZ-induced diabetic mice. The mass of the marginal islet was approximately 2000 IEQs, which is comparable to that required for the renal subcapsular space, a highly vascularized site. CONCLUSIONS: Therefore, PLGA-based bio-artificial devices prevascularized with hypo-MSCs could be a useful modality for successful subcutaneous islet transplantation, which is of high clinical relevance.
Assuntos
Hipóxia/metabolismo , Precondicionamento Isquêmico , Transplante das Ilhotas Pancreáticas , Células-Tronco Mesenquimais/citologia , Animais , Glicemia/fisiologia , Diabetes Mellitus Experimental/fisiopatologia , Precondicionamento Isquêmico/métodos , Ilhotas Pancreáticas/citologia , Transplante das Ilhotas Pancreáticas/métodos , Transplante de Células-Tronco Mesenquimais/métodos , Camundongos SCID , Transplante Heterólogo/métodosRESUMO
BACKGROUND: Anti-CD154 monoclonal antibody (mAb) treatment has been known to have potential to induce immune tolerance in organ transplantation. Several studies have suggested the involvement of CD4+ regulatory T cells (Treg s) in xeno-immune tolerance. However, the characteristics of Treg s and the mechanisms of their regulatory functions in islet xenotransplantation have not been clearly defined. METHOD: Adult porcine islet cells were isolated and purified, and were transplanted under the kidney capsule of diabetic C57BL/6J mice with the administration of 0.5 mg/mouse of anti-CD154 mAb on 0, 1, 3, 5, and 7 days post-transplantation (DPT). The graft survival was monitored by blood glucose level. The islet graft and recipients' cells were analyzed by immunohistochemistry (IHC), flow cytometry, enzyme-linked immunosorbent spot (ELISPOT) assay, and mixed-lymphocyte reaction. RESULTS: Short-term anti-CD154 mAb monotherapy enabled the porcine islet graft to survive indefinitely in diabetic mice (n = 18). Immunohistochemical staining showed significantly higher ratio of CD4+ Foxp3+ Treg s in the peri-graft site, but not in the spleen and kidney-draining lymph node of the recipient mice. Depletion of Treg s evoked graft rejection, and adoptive transfer of Treg s from anti-CD154 mAb-treated recipients provided protection to the graft from rejection. These Treg s showed more potent suppressive capacity than those from the untreated control and were found to be porcine antigen-specific. CONCLUSIONS: In this study, we showed that anti-CD154 mAb monotherapy resulted in indefinite porcine islet graft survival in mice. The porcine-specific CD4+ Foxp3+ Treg s in the peri-graft site played the critical role in the protection of islet graft from rejection, which suggests a prospective immunosuppressive strategy for islet xenotransplantation.
Assuntos
Anticorpos Monoclonais/uso terapêutico , Linfócitos T CD4-Positivos/imunologia , Ligante de CD40/imunologia , Fatores de Transcrição Forkhead/imunologia , Rejeição de Enxerto/prevenção & controle , Transplante das Ilhotas Pancreáticas , Transplante Heterólogo , Animais , Anticorpos Monoclonais/imunologia , Biomarcadores/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Diabetes Mellitus Experimental/cirurgia , Ensaio de Imunoadsorção Enzimática , Citometria de Fluxo , Fatores de Transcrição Forkhead/metabolismo , Rejeição de Enxerto/diagnóstico , Rejeição de Enxerto/imunologia , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Suínos , Resultado do TratamentoRESUMO
Pig-to-nonhuman primate (NHP) islet transplantation has been widely conducted as a preclinical xenotransplantation model prior to human clinical trial. Portal vein thrombosis is one of the complications associated with islet infusion through the portal vein into the liver. Here, we briefly report severe case of ascites formation accompanied by portal vein thrombi after pig-to-NHP islet xenotransplantation in a rhesus monkey. Meticulous prophylactic treatment such as continuous heparin infusion should be implemented to prevent portal vein thrombi in pig-to-NHP islet transplantation models.
Assuntos
Ascite/complicações , Veia Porta/transplante , Trombose/complicações , Transplante Heterólogo/efeitos adversos , Animais , Ascite/cirurgia , Rejeição de Enxerto/etiologia , Sobrevivência de Enxerto/fisiologia , Transplante das Ilhotas Pancreáticas/métodos , Macaca mulatta , SuínosRESUMO
Porcine corneas may be good substitutes for human corneas in donor shortage. Therefore, we evaluated the efficacy and safety of an anti-CD40 antibody-based regimen compared with an anti-CD20 antibody-based regimen on the survival of full-thickness corneas in pig-to-rhesus xenotransplant. Thirteen Chinese rhesuses underwent full-thickness corneal xenotransplant. Six were administered anti-CD40 antibody, and the others were administered anti-CD20 antibody, basiliximab, and tacrolimus. Graft survival and changes in lymphocyte, donor-specific and anti-Galα1,3Galß1,4GlcNAc-R (αGal) antibody, and aqueous complement levels were evaluated. Treatment with the anti-CD40 antibody (>511, >422, >273, >203, >196, 41 days) and anti-CD20 antibody (>470, 297, >260, >210, >184, 134, >97 days) resulted in long-term survival of grafts. In the anti-CD20 group, the number of activated B cells was significantly lower than that in the anti-CD40 group, and the level of aqueous complements at 6 months was significantly higher than the preoperative level. There were no differences in the levels of T cells or donor-specific and anti-αGal antibodies between the 2 groups. In the anti-CD20 group, 3 primates had adverse reactions. In conclusion, both the anti-CD40 antibody- and the anti-CD20 antibody-based protocols were effective for the long-term survival of full-thickness corneal xenografts, but the anti-CD40 antibody-based treatment had fewer adverse effects.