-
[show abstract]
[hide abstract]
ABSTRACT: The emerging field of vascular composite allotransplantation (VCA) has become a clinical reality. Building upon cutting edge understandings of transplant surgery and immunology, complex grafts such as hands and faces can now be transplanted with success. Many of the challenges that have historically been limiting factors in transplantation, such as rejection and the morbidity of immunosuppression, remain challenges in VCA. Because of the accessibility of most VCA grafts, and the highly immunogenic nature of the skin in particular, VCA has become the focal point for cross-disciplinary approaches to developing novel approaches for some of the most challenging immunological problems in transplantation, particularly the early diagnoses and assessment of rejection. This paper provides a historically oriented introduction to the field of organ transplantation and the evolution of VCA.
Clinical and Developmental Immunology 01/2013; 2013:402980. · 1.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Organ/tissue transplantation has become an effective therapy for end-stage diseases. However, immunosuppression after transplantation may cause severe side effects. Donor-specific transplant tolerance was proposed to solve this problem. In this study, we report a novel method for inducing and maintaining heart allograft tolerance rats. First, we induced indefinite vascularized hind-limb allograft survival with a short-term antilymphocyte serum + Cyclosporine A treatment. Peripheral blood chimerism disappeared 6-7 weeks after immunosuppression was withdrawn. Then the recipients accepted secondary donor-strain skin and heart transplantation 200 days following vascularized hind-limb transplantation without any immunosuppression, but rejected third party skin allografts, a status of donor-specific tolerance. The ELISPOT results suggested a mechanism of clone deletion. These findings open new perspectives for the role of vascularized hind-limb transplant in the induction and maintenance of organ transplantation tolerance.
Clinical and Developmental Immunology 01/2013; 2013:483856. · 1.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Preserving and enhancing the primary function of transplanted islets is not only crucial for improving the outcome of the islet transplantation, but is also important for reducing the islet mass required to achieve insulin independence. Uncoupling protein 2 (UCP2) is a member of the uncoupling protein family, which is localized to the inner mitochondrial membrane and negatively regulates insulin secretion in the pancreatic β-cells. In this study, we assessed the importance of UCP2 in improving islet graft primary function by using UCP2 gene-knockout (UCP2-KO) mice in a syngeneic islet transplantation model. Islets were isolated from UCP2-KO or wild-type (WT) C57BL/6J mice. The effects of deficiency of UCP2 on islet transplantation and islet function were determined. Two hundred islets from UCP2-KO, but not from WT, donors were capable of completely restoring normoglycemia in 1 week in all syngeneic diabetic recipients. Islets harvested from UCP2-KO mice secreted onefold more insulin in GSIS assay than that from WT mice, and maintained normal GSIS after 72-h exposure to high glucose challenge. In addition, UCP2-KO islets expressed twofold higher Bcl-2 mRNA than that from WT islets, and were resistant to high glucose and proinflammatory cytokine induced death. Our study explored a potential mechanism that may explain the benefit of UCP2-KO islets in islet transplantation. Targeting UCP2 may provide a novel strategy to improve primary function of transplanted islets and reduce the number of islets required in transplantation.
Cell Transplantation 01/2011; 20(3):421-9. · 5.13 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The critical roles of TGF-β in the reciprocal differentiation of tolerance-promoting CD4(+)Foxp3(+) regulatory T cells (Tregs) and proinflammatory Th17 effector cells affect alloimmune reactivity and transplant outcome. We reasoned that a strategy to harness TGF-β and block proinflammatory cytokines would inhibit the differentiation of Th17 cells and strengthen the cadre of Tregs to promote tolerance induction and long-term allograft survival. In this study, we report the development of a long-lasting autoactive human mutant TGF-β1/Fc fusion protein that acts in conjunction with rapamycin to inhibit T cell proliferation and induce the de novo generation of Foxp3(+) Treg in the periphery, while at the same time inhibiting IL-6-mediated Th17 cell differentiation. Short-term combined treatment with TGF-β1/Fc and rapamycin achieved long-term pancreatic islet allograft survival and donor-specific tolerance in a mouse model. This effect was accompanied by expansion of Foxp3(+) Tregs, enhanced alloantigen-specific Treg function, and modulation of transcript levels of Foxp3, IL-6, and IL-17. Our strategy of combined TGF-β1/Fc and rapamycin to target the IL-6-related Tregs and Th17 signaling pathways provides a promising approach for inducing transplant tolerance and its clinical application.
The Journal of Immunology 10/2010; 185(8):4750-9. · 5.79 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: It has been reported that Th1 to Th2 immune deviation effectively promotes peripheral tolerance in situations involving a limited T cell clone size, such as T cell-dependent autoimmunity and transplantation across minor, but not major, histocompatibility barriers. In this study, we tested the hypothesis that while Th1 to Th2 immune deviation fails to induce tolerance in the MHC-mismatched islet allograft model, it may promote a state that is permissive for tolerance induction. Here, we report that anti-IL-12 did not prevent acute rejection of islet allografts when administered alone. In conjunction with CTLA4/Fc, however, anti-IL-12 greatly facilitated long-term engraftment in three MHC-mismatched strain combinations. Similarly, while non-cytolytic IL-4/Fc, a long-lasting form of IL-4, did not prevent acute graft rejection when administered alone, a low, but not a high, dose of IL-4/Fc synergized with CTLA4/Fc in inducing significant levels of islet allograft tolerance. Moreover, by using a skin allograft adoptive transfer model, we show that these effects induced by anti-IL-12 and IL-4/Fc treatment were associated with an enhancement of the suppressive properties of CD4(+)CD25(+) regulatory T cells. Thus, anti-IL-12 and low-dose IL-4/Fc facilitate, but do not cause, islet allograft tolerance in mice by increasing the immunosuppressive potency of CD4(+)CD25(+) regulatory T cells.
Cytokine 09/2010; 51(3):311-9. · 3.02 Impact Factor
