Allotransplant Survival Research Articles

The Synergistic Effect of Full-Spectrum Light Therapy and Transient Immunosuppressants Prolonged Allotransplant Survival.

The lifelong administration of immunosuppressants remains the largest drawback in vascularized composite allotransplantation (VCA). Therefore, developing alternative strategies to minimize the long-term use of immunosuppressive agents is crucial. This study investigated whether full-spectrum bright light therapy (FBLT) combined with short-term immunosuppressant therapy could prolong VCA survival in a rodent hindlimb model. Hindlimb allotransplantation was conducted from Brown-Norway to Lewis rats, and the rats were divided into 4 groups. Group 1 did not receive treatment as a rejection control. Group 2 received FBLT alone. Group 3 was treated with short-term antilymphocyte serum (ALS) and cyclosporine A (CsA). Group 4 was administered short-term ALS/CsA combined with FBLT for 8 weeks. Peripheral blood and transplanted tissues were collected for analysis. The results revealed median survival time of FBLT alone (group 2) did not increase allograft survival compared with the control (group 1). However, in group 4, FBLT combined with short-term ALS/CsA, median composite tissue allograft survival time (266 days) was significantly prolonged compared with groups 1 (11 days), 2 (10 days), and 3 (41 days) ( P < 0.01). Group 4 also showed a significant increase in regulatory T cells ( P = 0.04) and transforming growth factor-β1 levels ( P = 0.02), and a trend toward a decrease in interleukin-1β levels ( P = 0.03) at 16 weeks after transplantation as compared with control (group 1). FBLT combined with short-term immunosuppressants prolonged allotransplant survival by modulating T-cell regulatory functions and antiinflammatory cytokine expression. This approach could be a potential strategy to increase VCA survival. Full-spectrum light therapy could be a potential strategy to increase vascularized composite allotransplant survival.

Local Delivery of Adipose Stem Cells Promotes Allograft Survival in a Rat Hind-Limb Model of Vascularized Composite Allotransplantation.

Adipose stem cells (ASCs) are a promising cell-based immunotherapy because of their minimally invasive harvest, high yield, and immunomodulatory capacity. In this study, the authors investigated the effects of local versus systemic ASC delivery on vascularized composite allotransplant survival and alloimmune regulation. Lewis rats received hind-limb transplants from Brown Norway rats and were administered donor-derived ASCs (passage 3 or 4, 1 × 10 6 cells/rat) locally in the allograft, or contralateral limb, or systemically at postoperative day 1. Recipients were treated intraperitoneally with rabbit anti-rat lymphocyte serum on postoperative days 1 and 4 and daily tacrolimus for 21 days. Limb allografts were monitored for clinical signs of rejection. Donor cell chimerism, immune cell differentiation, and cytokine expression in recipient lymphoid organs were measured by flow cytometric analysis. The immunomodulation function of ASCs was tested by mixed lymphocyte reaction assay and ASC stimulation studies. Local-ASC-treated recipients achieved significant prolonged allograft survival (85.7% survived >130 days; n = 6) compared with systemic-ASC and contralateral-ASC groups. Secondary donor skin allografts transplanted to the local-ASC long-term surviving recipients accepted permanently without additional immunosuppression. The increases in donor cell chimerism and regulatory T-cells were evident in blood and draining lymph nodes of the local-ASC group. Moreover, mixed lymphocyte reaction showed that ASCs inhibited donor-specific T-cell proliferation independent of direct ASC-T-cell contact. ASCs up-regulated antiinflammatory molecules in response to cytokine stimulation in vitro. Local delivery of ASCs promoted long-term survival and modulated alloimmune responses in a full major histocompatibility complex-mismatched vascularized composite allotransplantation model and was more effective than systemic administration. ASCs are a readily available and abundant source of therapeutic cells that could decrease the amount of systemic immunosuppression required to maintain limb and face allografts.

Preconditioned Mesenchymal Stromal Cells to Improve Allotransplantation Outcome.

Mesenchymal stromal cells (MSCs) are tissue-derived progenitor cells with immunomodulatory as well as multilineage differentiation capacities, and have been widely applied as cellular therapeutics in different disease systems in both preclinical models and clinical studies. Although many studies have applied MSCs in different types of allotransplantation, the efficacy varies. It has been demonstrated that preconditioning MSCs prior to in vivo administration may enhance their efficacy. In the field of organ/tissue allotransplantation, many recent studies have shown that preconditioning of MSCs with (1) pretreatment with bioactive factors or reagents such as cytokines, or (2) specific gene transfection, could prolong allotransplant survival and improve allotransplant function. Herein, we review these preconditioning strategies and discuss potential directions for further improvement.

Combination of a CD26 Inhibitor, G-CSF, and Short-term Immunosuppressants Modulates Allotransplant Survival and Immunoregulation in a Rodent Hindlimb Allotransplant Model.

Recent studies have demonstrated that inhibition of CD26 potentiates stromal cell-derived factor-1α (SDF-1α), promotes tissue regeneration, and suppresses the rejection of organ transplants. This study investigated whether the combination of a CD26 inhibitor (CD26i) with granulocyte colony-stimulating factor (G-CSF) and short-term immunosuppressants modulates vascularized composite tissue allotransplant survival in a rodent orthotopic hindlimb allotransplant model. The hindlimb allotransplantation from Brown-Norway to Lewis rats was divided into 4 groups. Group 1 (controls) did not receive any treatment. Group 2 was treated with short-term antilymphocyte serum (ALS) and cyclosporine-A (CsA). Group 3 was administrated CD26i and G-CSF. Group 4 received a combination of CD26i/G-CSF/ALS/CsA. Each subgroup comprised 10 rats. Peripheral blood and sampling of transplanted tissues were collected for immunological and histological analysis. The results revealed that allotransplant survival was found to be significantly prolonged in group 4 with CD26i/G-CSF/ALS/CsA treatment compared with those in the other groups. The interleukin-10 and transforming growth factor-βl levels, the percentage of CD4+/CD25+/FoxP3+ T cells, as well as the levels of SDF-1α expressions were significantly increased in group 4 compared with those in the other groups. Group 4 revealed a statistical increase in the percentage of donor cells (RT1n) expression in the recipient peripheral blood, and the mixed lymphocyte reaction showed hyporesponsiveness of the T cells to donor alloantigens. The combination of CD26i/G-CSF and short-term immunosuppressants prolongs allotransplant survival by inducing immunoregulatory effects and enhancing the percentage of SDF-1α expression. This immunomodulatory approach has great potential as a strategy to increase vascularized composite allotransplantation survival.

Adipose-derived stromal cells modulating composite allotransplant survival is correlated with B cell regulation in a rodent hind-limb allotransplantation model

BackgroundOur previous studies demonstrated that adipose-derived mesenchymal stromal cells (ASCs) have immunomodulatory effects that prolong allograft survival in a rodent hind-limb allotransplant model. In this study, we investigated whether the effects of immunomodulation by ASCs on allograft survival are correlated with B cell regulation.MethodsB cells isolated from splenocytes were cocultured with ASCs harvested from adipose tissue from rodent groin areas for in vitro experiments. In an in vivo study, hind-limb allotransplantation from Brown-Norway to Lewis rats was performed, and rats were treated with ASCs combined with short-term treatment with anti-lymphocyte serum (ALS)/cyclosporine (CsA) as immunosuppressants. Peripheral blood and transplanted tissue were collected for further analysis.ResultAn in vitro study revealed that ASCs significantly suppressed lipopolysaccharide-activated B cell proliferation and increased the percentage of Bregs. The levels of immunoregulatory cytokines, such as TGF-β1 and IL-10, were significantly increased in supernatants of stimulated B cells cocultured with ASCs. The in vivo study showed that treatment with ASCs combined with short-term ALS/CsA significantly reduced the B cell population in alloskin tissue, increased the proportion of circulating CD45Ra+/Foxp3+ B cells, and decreased C4d expression in alloskin.ConclusionASCs combined with short-term immunosuppressant treatment prolong allograft survival and are correlated with B cell regulation, C4d expression and the modulation of immunoregulatory cytokines.

The suppression effect of dendritic cells maturation by adipose-derived stem cells through TGF-β1 related pathway

BackgroundOur previous studies demonstrated that adipose-derived stem cells (ASCs) could modulate regulatory T cells (Treg) and prolong hind-limb allotransplant survival in vitro and in vivo. Dendritic cells (DCs) play a pivotal role in innate and adaptive immunity. The aim of this study is to investigate the underlying mechanism of ASCs in modulating DC maturation. Materials and MethodsASCs were isolated from rodent adipose tissue, DCs were derived from the bone marrow, and CD4+ T cells were purified from splenocytes. DCs were co-cultured with ASCs to evaluate the suppressive effects of ASCs. CD4+ T-cells were co-cultured with DCs pre-treated with or without ASCs. The cell surface markers of DCs were analyzed by flow cytometry. T-cell proliferation was analyzed by the BrdU proliferation test. Tolerogenic cytokines and indoleamine 2,3-dioxygenase (IDO) expressions after different treatments were detected by quantitative real-time PCR, Western blotting, and ELISA analysis. ResultASCs suppressed DC maturation as evidenced by low expressions of CD80, CD86, and MHC-II. Also, ASC-treated mature DCs showed higher levels of TGF-β1, IL-10, and IDO expressions, as compared to that in matured DCs (mDCs) alone. ASC-treated mDCs co-cultured with CD4+ T cells revealed a significant higher percentage of Treg than mDC without treatment. The IDO level in ASC-treated mDCs and Treg induction effects were blocked by the ASCs pre-treated with TGF-β1 siRNAs, but not IL-10 siRNAs. ConclusionASC-modulated DC maturation correlated with TGF-β1 secretion, IDO expression, and Treg induction. ASCs could be used as a potential immunomodulatory strategy for clinical application in allotransplantation.

Recipient Adipose-Derived Stem Cells Enhance Recipient Cell Engraftment and Prolong Allotransplant Survival in a Miniature Swine Hind-Limb Model

Donor mesenchymal stem cells (MSCs) could prolong vascularized composite allotransplantation (VCA) survival in our previous studies. However, recipient adipose tissue is easier to harvest than donor tissue for preconditioning modulation. Hence, this study investigated the efficacy of recipient autologous adipose-derived stem cells (rADSCs) for VCA survival. The heterotopic hind-limb transplantation from female donor to male recipient was performed in outbred miniature swine. Group I (n = 6) was untreated controls. Group II (n = 4) obtained rADSCs infusions (given on weeks 0, +1, +2, and +3). Group III (n = 4) obtained tacrolimus (FK506, weeks 0 to +4). Group IV (n = 8) received irradiation (IR; day −1), FK506 (weeks 0 to +4), and rADSC infusions (weeks 0, +1, +2, and +3). The results revealed treatment with multiple injections of rADSCs along with IR and FK506 resulted in a statistically significant increase in allograft survival. The percentage of CD4+/CD25+/Foxp3+ regulatory T cells were significantly increased in the rADSC-IR-FK506 group as compared to controls. Analysis of recipient peripheral blood revealed that transforming growth factor β1 (TGFβ1) was significantly increased in the rADSC-IR-FK506 group. The polymerase chain reaction (PCR) analysis and immunohistochemical staining showed recipient sex-determining region of Y (SRY) chromosome gene expression existed in donor allotissues in the rADSC-IR-FK506 group. These results indicate that rADSCs in addition to IR and transient immunosuppressant could prolong allotransplant survival, modulate T-cell regulation, and enhance recipient cell engraftment into the allotransplant tissues.

Differential depletion of total T cells and regulatory T cells and prolonged allotransplant survival in CD3Ɛ humanized mice treated with polyclonal anti human thymocyte globulin.

Thymoglobulin (ATG) is a polyclonal rabbit antibody against human thymocytes used as a T cell-depleting agent to prevent or treat allotransplant rejection. The aim of the present study was to investigate the effect of low dose ATG treatment exclusively on T cells using a humanized BALB/c human CD3Ɛ transgenic mouse model expressing both human and murine T cell receptors (TCR). Mice received a single intravenous (i.v.) injection of ATG. Blood and peripheral lymphoid organs were obtained after different time points. We found a significant T cell depletion in this mouse model. In addition, regulatory T cells (Tregs) proved to be less sensitive to depletion than the rest of T cells and the Treg:non-Treg ratio was therefore increased. Finally, we also investigated the effect of ATG in a heterotopic allogenic murine model of heart transplantation. Survival and transplant function were significantly prolonged in ATG-treated mice. In conclusion, we showed (a) an immunosuppressive effect of ATG in this humanized mouse model which is exclusively mediated by reactivity against human CD3Ɛ; (b) provided evidence for a relative resistance of Tregs against this regimen; and (c) demonstrated the immunomodulatory effect of ATG under these experimental circumstances by prolongation of heart allograft survival.

Recipient Adipose-derived Stem Cells Enhance Recipient Cell Engraftment and Prolong Allotransplant Survival in a Miniature Swine Hind-limb Model

Recipient Adipose-derived Stem Cells Enhance Recipient Cell Engraftment and Prolong Allotransplant Survival in a Miniature Swine Hind-limb Model

Adipose-Derived Stem Cell Modulation of T-Cell Regulation Correlates with Heme Oxgenase-1 Pathway Changes

The authors' previous proteome study revealed that haptoglobin was involved in adipose-derived stem cell modulation of allotransplant survival and T-cell regulation to induce immune tolerance. This study investigated whether adipose-derived stem cells could modulate T-cell regulation through haptoglobin and the downstream heme oxgenase-1 pathway in vitro. Splenocytes were isolated from Lewis rat spleens and then CD3 T cells were purified using anti-CD3 beads. Adipose-derived stem cells were harvested from Lewis rats and co-cultured with the T cells. After Transwell co-culture at different periods, the authors analyzed cell proliferation with a bromodeoxyuridine assay. Cell extractions and culture supernatants were collected for further analysis. Heme oxgenase-1 and related protein expression levels from the adipose-derived stem cells and T cells were detected using Western blotting. The related cytokine expression levels were analyzed with enzyme-linked immunosorbent assay kits. Flow cytometry was used to detect the regulatory T-cell proportion. The adipose-derived stem cells significantly suppressed T-cell proliferation. The regulatory T-cell percentages were significantly increased in the adipose-derived stem cells that were co-cultured with T cells compared with T cells alone without adipose-derived stem cell co-culture. Heme oxgenase-1 expression in concanavalin A-stimulated T cells that were co-cultured with adipose-derived stem cells revealed a significant increase compared with concanavalin A-stimulated T cells alone. Cytokine assays of the culture supernatants revealed that transforming growth factor-β and interleukin-10 were significantly increased and interferon-γ was statistically decreased in the adipose-derived stem cell-co-cultured T-cell group compared with other groups; however, blockade with a heme oxgenase-1 inhibitor (zinc protoporphyrin IX) protected against these changes. Adipose-derived stem cells modulate T-cell proliferation and enhance regulatory T-cell expression, and this correlated with heme oxgenase-1 expression and related cytokine pathway changes.

Complications chirurgicales de la transplantation rénale

To report the nature, incidence, diagnosis and treatment options of surgical complications after renal transplantation. Relevant publications were identified through Medline (http://www.ncbi.nlm.nih.gov/) and Embase (http://www.embase.com/) database from 1960 to 2016 using the following keywords "fistula; lymphocele; stricture; thrombosis", in association with "renal transplantation" in Title/Abstract field. Articles were selected according to methods, language of publication and relevance. A total of 7618 articles were identified including specifically 981 for vascular complications, 1016 for urologic complications and 239 for lymphocele; after careful selection 190 publications were eligible for our review. Surgical complications occur in 1to 30% of renal transplantations while being incompletely reported without consensual management. Angioplasty techniques led to a significant improvement of short- and long-term vascular complications outcome. Risk factors for transplant thrombosis are a right allotransplant, multiple renal arteries or vasculopathy in the donor, diabetes, arterial disease or thrombophilia in the recipient and hemodynamic changes during procedure. Urinary complications and lymphocele significantly impair overall outcome and recipients quality of life with no demonstrated impact on allotransplant survival. Immediate or salvage pelvi-ureterostomy is a main treatment option for ureteral strictures and fistula. Prevention of surgical complications following renal transplantation relies on careful allotransplant preparation and strict respect of surgical best practices. Increasing comorbidities in recipients as well as marginal donors are significant limits for the improvement of post-transplant surgical outcome.

Recipient-derived angiogenesis with short term immunosuppression increases bone remodeling in bone vascularized composite allotransplantation: A pilot study in a swine tibial defect model.

Current vascularized composite allotransplantation (VCA) transplantation protocols rely upon life-long immune modulation to maintain tissue perfusion. Alternatively, bone-only VCA viability may be maintained in small animal models using surgical angiogenesis from implanted autogenous vessels to develop a neoangiogenic bone circulation that will not be rejected. This study tests the method's efficacy in a large animal model as a bridge to clinical practice, quantifying the remodeling and mechanical properties of porcine tibial VCAs. A segmental tibial defect was reconstructed in Yucatan miniature swine by transplantation of a matched tibia segment from an immunologically mismatched donor. Microsurgical repair of nutrient vessels was performed in all pigs, with simultaneous intramedullary placement of an autogenous arteriovenous (AV) bundle in Group 2. Group 1 served as a no-angiogenesis control. All received 2 weeks of immunosuppression. After 16 weeks, micro-CT and histomorphometric analyses were used to evaluate healing and remodeling. Axial compression and nanoindentation studies evaluated bone mechanical properties. Micro-CT analysis demonstrated significantly more new bone formation and bone remodeling at the distal allotransplant/recipient junction and on the endosteal surfaces of Group 2 tibias (p = 0.03). Elastic modulus and hardness were not adversely affected by angiogenesis. The combination of 2 weeks of immunosuppression and autogenous AV-bundle implantation within a microsurgically transplanted tibial allotransplant permitted long-term allotransplant survival over the study period of 16 weeks in this large animal model. Angiogenesis increased bone formation and remodeling without adverse mechanical effects. The method may allow future composite-tissue allotransplantation of bone without the risks associated with long-term immunosuppression. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1242-1249, 2017.

The Effect of Transient Local Anti-inflammatory Treatment on the Survival of Pig Retinal Progenitor Cell Allotransplants.

The development of photoreceptor replacement therapy for retinal degenerative disorders requires the identification of the optimal cell source and immunosuppressive regimen in a large animal model. Allotransplants are not acutely rejected in swine subretinal space, although it is not known if survival can be improved with immunosuppression. Here we investigated the survival and integration of expanded pig retinal progenitor cells (pRPCs) in normal recipients with and without transient anti-inflammatory suppression. pRPCs were derived from the neural retina of E60 GFP transgenic pigs, expanded for six passages, characterized, and transplanted into the subretinal space of 12 pigs. Six recipients received a single intravitreal injection of rapamycin and dexamethasone. pRPCs expressed the photoreceptor development genes Sox2, Pax6, Lhx2, Crx, Nrl, and Recoverin in vitro. Transplanted cells were identified in 9 out of 12 recipients 4 weeks after the injection. pRPCs integrated primarily into the photoreceptor inner segment layer and outer nuclear layer with single cells present in the inner nuclear layer. Donor cells remained recoverin-positive and acquired rhodopsin. We did not observe any signs of graft proliferation. The immunosuppression did not affect the survival or distribution of grafts. No macrophage infiltration or loss of retinal structure was observed in either group. Local immunosuppression with rapamycin and dexamethasone does not improve the outcome of pRPC allotransplantation into the subretinal space. Survival and integration of pRPC together with the lack of graft proliferation suggests that allogeneic RPC transplantation without transient immunosuppression is a favorable approach for photoreceptor cell replacement.

Proteomic Analysis in Serum of Rat Hind-Limb Allograft Tolerance Induced by Immunosuppressive Therapy with Adipose-Derived Stem Cells

Adipose-derived stem cells combined with transient immunosuppression prolonged vascularized composite tissue allotransplant survival and induced immune tolerance in a rodent hind-limb model. The authors investigated serum proteins in the adipose-derived stem cell tolerance group and control group using proteomic study. An orthotopic hind-limb model from Brown-Norway to Lewis rats was used. The control group received no treatment. Rats in the tolerance group received combined treatments of short-term cyclosporine A, antilymphocyte serum, and multiple rounds of adipose-derived stem cells. Serum samples were analyzed. Spots of interest were subjected to in-gel trypsin digestion and matrix-assisted laser desorption ionization time-of-flight mass spectrometry to elucidate the peptide mass fingerprints. The mass spectrometric characteristics of the identified proteins were analyzed. Immunohistochemical analysis of transplanted tissue and enzyme-linked immunosorbent assay of serum were validated. Rats in the tolerance group had significantly higher amounts of β2-glycoprotein, α1-macroglobulin, rat-albumin, and vitamin D-binding protein, and significantly lower levels of haptoglobin compared with controls. Immunohistochemical staining of the alloskin indicated similar effects, such as up-regulated vitamin D-binding protein and down-regulated haptoglobin in the tolerance group compared with rejection controls (p < 0.05). Enzyme-linked immunosorbent assay revealed that vitamin D-binding protein was statistically increased (p < 0.05) and haptoglobin expression was significantly decreased (p < 0.01) in the tolerance group compared with the controls. There were significant differences in the serum proteomics between the tolerance and control groups. Down-regulated haptoglobin and up-regulated vitamin D-binding protein are involved in adipose-derived stem cell-induced immune tolerance and allotransplant survival.

Immunosuppressive Activity of Adipose Tissue-Derived Mesenchymal Stem Cells in a Rat Model of Hind Limb Allotransplantation

Many reports have shown that bone marrow–derived mesenchymal stem cells exhibit immunosuppressive effects in allogeneic transplantation. However, few reports have evaluated the immunosuppressive properties of adipose tissue–derived mesenchymal stem cells (ASCs) in vitro and in vivo. In this study, we investigated the immunosuppressive characteristics of ASCs, and investigated whether ASCs originating from donor rats prolong allotransplant survival in a rat hind limb allotransplantation model. T-cell proliferation stimulated by allogeneic stimuli or mitogen with or without ASCs originating from the donor was assessed in vitro. The effects of cellular contact or soluble factors on the inhibition of T-cell proliferation were also evaluated. In the in vivo study, cultured ASCs (1 × 105) that originated from the donor were injected into recipient animals intravenously immediately after operation, followed by 1 dose per day for 3 consecutive days post-transplantation. When immune rejection occurred, the survival time of allotransplants was determined and rejected tissue was histologically and immunochemically assessed for determining regulatory T-cell infiltration. ASCs inhibited the T-cell proliferation stimulated by alloantigen or mitogen in a dose-dependent manner, and recipient T cells proliferated less in animals treated with ASCs than in controls. Although ASCs were separated from T cells, ASCs persisted to elicit a suppressive effect. ASC culture supernatants did not inhibit T-cell proliferation; however, supernatants obtained from the mixed lymphocyte reaction in the presence of ASCs suppressed T-cell proliferation. ASCs prolonged allotransplant survival time, reduced inflammatory cell infiltration, and induced regulatory T cells. In conclusion, ASCs can exhibit in vitro immunosuppressive properties and prolong allotransplant survival time in a rat hind limb composite tissue allotransplantation model, possibly through the induction of regulatory T cells.

Zebularine Induces Long-Term Survival of Pancreatic Islet Allotransplants in Streptozotocin Treated Diabetic Rats

BackgroundCoping with the immune rejection of allotransplants or autologous cells in patients with an active sensitization towards their autoantigens and autoimmunity presently necessitates life-long immune suppressive therapy acting on the immune system as a whole, which makes the patients vulnerable to infections and increases their risk of developing cancer. New technologies to induce antigen selective long-lasting immunosuppression or immune tolerance are therefore much needed.Methodology/Principal FindingsThe DNA demethylating agent Zebularine, previously demonstrated to induce expression of the genes for the immunosuppressive enzymes indolamine-2,3-deoxygenase-1 (IDO1) and kynureninase of the kynurenine pathway, is tested for capacity to suppress rejection of allotransplants. Allogeneic pancreatic islets from Lewis rats were transplanted under the kidney capsule of Fischer rats previously made diabetic by a streptozotocin injection (40 mg/kg). One group was treated with Zebularine (225 mg/kg) daily for 14 days from day 6 or 8 after transplantation, and a control group received no further treatment. Survival of the transplants was monitored by blood sugar measurements. Rats, normoglycemic for 90 days after allografting, were subjected to transplant removal by nephrectomy to confirm whether normoglycemia was indeed due to a surviving insulin producing transplant, or alternatively was a result of recovery of pancreatic insulin production in some toxin-treated rats. Of 9 Zebularine treated rats, 4 were still normoglycemic after 90 days and became hyperglycemic after nephrectomy. The mean length of normoglycemia in the Zebularine group was 67±8 days as compared to 14±3 days in 9 controls. Seven rats (2 controls and 5 Zebularine treated) were normoglycemic at 90 days due to pancreatic recovery as demonstrated by failure of nephrectomy to induce hyperglycemia.Conclusions/SignificanceZebularine treatment in vivo induces a long-lasting suppression of the immune destruction of allogeneic pancreatic islets resulting in protection of allograft function for more than 10 weeks after end of treatment.

Long-term Existence of Donor Adipose-derived Stem Cells in the Recipient May Modulate the Vascularized Composite Tissue Allotransplantation Survival in a Rodent Model

Our previous studies have demonstrated donor adipose-derived stem cells (ASCs) combined with short-term immunosuppressant therapy could prolong vascularized composite tissue allotransplantation (VCA) survival in a rodent hind-limb model. In this study, we investigated whether the homing and migration of donor ASCs may modulate VCA survival. Orthotopic hind-limb transplants from male Wistar to Lewis rats were performed (day 0). Donor ASCs were propagated from the adipose-tissue and subculture originated from green fluorescent protein (GFP) transgenic Wistar rats. The transplanted rat (GFP-negative Lewis) received the immunosuppressive protocol similar to our previous design including short-term cyclosporine-A (CsA, days 0-+20), anti-lymphocyte serum (ALS; 0.5 ml i.p.; -4, +1), and three rounds of GFP+-ASCs (2 × 106 cells/time, i.v. on days +1, +7, and +21). The engraftment assessment of various donor and recipient tissues were performed by using immuno-fluorescent staining. Flow cytometry was performed to quantify the GFP+-ASCs. The results revealed allotransplant survival was significantly prolonged (>100 days) exclusively in ASC-ALS-CsA group which was well correlated with long-term existence of donor GFP-positive ASCs in the recipient. Flow cytometric analysis also revealed GFP+-ASCs apparent expression in the recipient peripheral blood in 2 weeks post-ASC infusion but skewing decrease post-transplantation. The immunofluorscent staining performed on tissue biopsy samples revealed the GFP positive cells existed in the alloskin and recipient skin and liver and spleen parenchymal tissues 2 weeks post-ASC injection. However, no apparent expressions of GFP+-ASCs were found in recipient tissues at 16 weeks post-transplantation except in recipient spleen parenchyma. These indicated donor ASCs long-term existed in the recipient spleen tissue and circulating blood may lead to prolong allograft survival.

Lymphocyte Differentiation and Effector Functions

Lymphocyte Differentiation and Effector Functions

Modulation of Immune Response and T-Cell Regulation by Donor Adipose-Derived Stem Cells in a Rodent Hind-Limb Allotransplant Model

In this study, the authors investigated whether donor adipose-derived stem cells have immunomodulatory effects, such as regulation of T cells, modulation of related cytokines, and prolongation of composite tissue allotransplantation survival, in a rodent hind-limb model. Adipose-derived stem cells were obtained from donor adipose tissue and co-cultured with CD3 T cells from allogenic splenocytes for in vitro studies. Orthotopic hind-limb allotransplants were performed from Brown Norway to Lewis rats (day 0). Group 1 (control group) did not receive any treatment. Group 2 received cyclosporin A on days 0 to 20. Group 3 received antilymphocyte serum (day -4 and day 1) and cyclosporin A (days 0 to 20). Group 4 received cyclosporin A (days 0 to 20), antilymphocyte serum (day -4 and day 1), and adipose-derived stem cells (2 × 10 cells/time administered intravenously on days 7, 14, and 21). Adipose-derived stem cells exert immunomodulatory effects including suppressing T-cell proliferation and increasing CD4/CD25/Foxp3 regulatory T cells in vitro. The in vivo study revealed that, compared with untreated control, rats administered adipose-derived stem cells along with transient antilymphocyte serum and cyclosporin A treatment had significantly prolonged allotransplant survival (p < 0.001), decreased allotissue rejection, significantly elevated donor cell chimerism, and increased CD4/CD25/Foxp3 regulatory T cells in peripheral blood and alloskin tissue with up-regulation of transforming growth factor-β and interleukin-10 levels. In combination with transient immunosuppression, adipose-derived stem cells modulate the immune system and significantly prolong allotransplant survival. The underlying mechanisms include changes in antiinflammatory cytokine expression and T-cell functions.

Living Bone Allotransplants Survive by Surgical Angiogenesis Alone: Development of a Novel Method of Composite Tissue Allotransplantation

Segmental bone defects pose reconstructive challenges. Composite tissue allotransplantation offers a potential solution but requires long-term immunosuppression with attendant health risks. This study demonstrates a novel method of composite-tissue allotransplantation, permitting long-term drug-free survival, with use of therapeutic angiogenesis of autogenous vessels to maintain circulation. Ninety-three rats underwent femoral allotransplantation, isotransplantation, or allografting. Group-1 femora were transplanted across a major histocompatibility complex barrier, with microsurgical pedicle anastomoses. The contralateral saphenous artery and vein (termed the AV bundle) of the recipient animal were implanted within the medullary canal to allow development of an autogenous circulation. In Group 2, allotransplantation was also performed, but with AV bundle ligation. Group 3 bones were frozen allografts rather than composite-tissue allotransplantation femora, and Group 4 bones were isotransplants. Paired comparison allowed evaluation of AV bundle effect, bone allogenicity (isogeneic or allogeneic), and initial circulation and viability (allotransplant versus allograft). Two weeks of immunosuppression therapy maintained blood flow initially, during development of a neoangiogenic autogenous blood supply from the AV bundle in patent groups. At eighteen weeks, skin grafts from donor, recipient, and third-party rats were tested for immunocompetence and donor-specific tolerance. At twenty-one weeks, bone circulation was quantified and new bone formation was measured. Final circulatory status depended on both the initial viability of the graft and the successful development of neoangiogenic circulation. Median cortical blood flow was highest in Group 1 (4.6 mL/min/100 g), intermediate in Group 4 isotransplants (0.4 mL/min/100 g), and absent in others. Capillary proliferation and new bone formation were generally highest in allotransplants (15.0%, 6.4 μm³/μm²/yr) and isotransplants with patent AV bundles (16.6%, 50.3 μm³/μm²/yr) and less in allotransplants with ligated AV bundles (4.4%, 0.0 μm³/μm²/yr) or allografts (8.1%, 24.1 μm³/μm²/yr). Donor and third-party-type skin grafts were rejected, indicating immunocompetence without donor-specific tolerance. In the rat model, microvascular allogeneic bone transplantation in combination with short-term immunosuppression and AV bundle implantation creates an autogenous neoangiogenic circulation, permitting long-term allotransplant survival with measurable blood flow.