ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.This study investigates the protective mechanism of prostaglandin E1(PGE1) against hepatic ischemia-reperfusion injury in vivo. It has been demonstrated that activated leukocytes contribute to ischemia-reperfusion injury, and that administration of the monoclonal antibody (mAb) for adhesion molecules reduces the injury by inhibiting leukocyte-endothelial cell adhesion. We therefore attempted to find out whether PGE1has an effect on the inhibition of neutrophil adherence to endothelial cells after reperfusion.Methods.We administered anti-intercellular adhesion molecule 1 (ICAM-1) mAb, antiserum against rat polymorphonuclear leukocytes, or PGE1to a rat model of left lobar ischemia for 60 min followed by reperfusion. Leukocyte adherence was observed by intravital fluorescence microscopy. The effect of PGE1on the expression of adhesion molecules was analyzed by immunohistochemistry and flow cytometry.Results.Ischemia-reperfusion caused endothelial dysfunction and hepatocellular injury with leukostasis in postsinusoidal venules. Anti-ICAM-1 mAb administration or leukopenia ameliorated both the hepatocellular injury and endothelial dysfunction. Although PGE1administration did not affect the serum interleukin-8 level, it significantly decreased hepatic injury and leukostasis in the reperfused liver. Immunohistochemical findings showed that PGE1decreased ICAM-1 expression on endothelial cells, but did not affect lymphocyte function-associated antigen 1, and membrane attack complex 1 on neutrophils in flow cytometric analysis.Conclusions.We conclude that PGE1protects the liver against ischemia-reperfusion injury by reducing leukocyte-endothelial cell adhesion via down-modulation of ICAM-1 expression on the endothelium.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.Increasing clinical evidence suggests that delayed initial function secondary to ischemia/reperfusion injury alone, and particularly in combination with early episodes of acute rejection, reduces kidney allograft survival over time.Methods.We investigated changes developing over the long term following a standardized ischemia/reperfusion insult in a Lewis rat model. The left kidney was isolated in a uninephrectomized host and cooled, and the pedicle was clamped for 45 min. Animals were followed for 48 weeks after initial renal injury. Organs were removed serially (4, 8, 16, 24, 32, 40, and 48 weeks) for immunohistology and reverse transcriptase polymerase chain reaction.Results.Progressive proteinuria developed after 8 weeks. By immunohistology, CD4+leukocytes and ED-1+macrophages infiltrated the ischemic organs in parallel with up-regulation of major histocompatibility complex class II antigen expression. Because macrophages have been shown to be critical in chronic changes in other models, they were examined primarily in these studies. By reverse transcriptase polymerase chain reaction, macrophage-derived, fibrosis-inducing factors (transforming growth factor-β, interleukin 6, and tumor necrosis factor-α) remained highly and constantly expressed throughout the follow-up period. The long-term influence of initial treatment with the soluble form of P-selectin glycoprotein ligand-1, a soluble ligand for P- and E-selectin, was then examined. All functional and structural changes remained at relative baseline, similar to uninephrectomized controls.Conclusions.These data suggest that blocking the initial selectin-mediated step after ischemia/reperfusion injury, which triggers significant early cellular and molecular events, also reduces later renal dysfunction and tissue damage over time. In part, the findings may be explained by the sparing of functioning nephron units, which if destroyed or compromised by the original insult, may contribute to long-term graft failure. This approach may be important clinically in the transplantation of kidneys from non-heart-beating or marginal donors or organs experiencing prolonged ischemic times.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.The recurrent autoimmune response to syngeneic pancreatic islet grafts transplanted into nonobese diabetic (NOD) mice is cell-mediated and relatively resistant to cyclosporine (CsA) therapy. Therefore, we asked whether interleukin (IL)-4 and IL-10, cytokines that inhibit cell-mediated immunity, might improve the therapeutic effect of CsA.Methods.We compared the survival of syngeneic islet grafts transplanted into diabetic NOD mice treated with IL-4, IL-10, and CsA, administered as single agents and in combinations. Additionally, we measured mRNA levels of type 1 cytokines (interferon-γ [IFN-γ], IL-2, and IL-12), type 2 cytokines (IL-4 and IL-10), and transforming growth factor-β (TGF-β) to determine whether graft rejection or survival might correlate with expression of these cytokines in the grafts.Results.CsA (20 mg/kg/day) significantly prolonged islet graft survival(median: 20 days vs. 10 days for vehicle-treated mice). Neither IL-4 (2.5μg, twice daily), nor IL-10 (10 μg, twice daily) significantly prolonged islet graft survival. By contrast, combination therapy with CsA and IL-10 significantly prolonged islet graft survival (median: 34 days) compared with vehicle-treated mice (median: 10 days), and combination therapy with CsA and IL-4 significantly prolonged islet graft survival (median: 59 days) compared with both vehicle-treated mice (median: 10 days) and mice treated with CsA alone (median: 20 days). Islet grafts from normoglycemic mice treated with CsA plus IL-10, and with CsA plus IL-4, were surrounded but not infiltrated by mononuclear leukocytes and β cells were intact, whereas islet grafts from mice treated with vehicle, IL-4, IL-10, and CsA (as single agents) were infiltrated by mononuclear leukocytes and fewer β cells were detected. Polymerase chain reaction analysis of cytokine mRNA expression in islet grafts at 8-12 days after transplantation revealed that CsA decreased mRNA levels of type 1 cytokines (IFN-γ and IL-12p40), whereas CsA plus IL-10 did not, and CsA plus IL-4 increased mRNA levels of IFN-γ, IL-12p40, and TGF-β.Conclusions.These results demonstrate that IL-4, and to a lesser extent IL-10, improves the ability of CsA to prevent autoimmune destruction of β cells in syngeneic islets transplanted into diabetic NOD mice; however, there is no simple correlation between the protective effects of the different treatment regimens (CsA, CsA plus IL-4, and CsA plus IL-10) and mRNA levels of type 1 cytokines (IFN-γ, IL-2, and IL-12), type 2 cytokines (IL-4 and IL-10), or TGF-β in the islet grafts.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.The relative roles of humoral and cell-mediated immunity in generating chronic allograft arteriopathy have been considered for several years. We have sought definitive evidence regarding these questions using heart transplants between mouse strains selected to isolate the effects of each form of immune responsiveness.Methods.B10.BR hearts were transplanted to B cell-deficient recipients that are devoid of immunoglobulins (μMT). Their vessels were compared with those of transplants to fully reactive recipients of the same genetic background(C57BL/6). Additional evidence came from comparisons in other strain combinations.Results.Transplants to B cell-deficient and normal recipients developed cellular coronary endothelialitis, with destruction of the arterial media, accompanied by the adherence of T lymphocytes and macrophages to endothelial surfaces. In B cell-deficient recipients, there was no centripetal migration of smooth muscle, α-actin-positive myointimal cells and little deposition of collagen or ground substance, compared with lesions in fully reactive C57BL/6 recipients in which these changes are prominent. In two other donor-recipient combinations in which anti-donor antibodies are generally undetectable (B10.BR→B10.A and 129→C57BL/6), intimal fibrosis was uncommon. However, B10.A recipients became capable of producing fibrous lesions in B10.BR hearts when given anti-donor, class I antibody by passive transfer, as we have observed previously inscidrecipients.Conclusions.Taken together, these findings indicate that endothelialitis is antibody-independent, whereas antibodies potentiate and can be sufficient for fully developed, fibrous, chronic allograft vasculopathy. Therapeutic strategies for controlling chronic lesions must consider inhibition of the humoral response.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.A replication-defective retrovirus BAG vector was tested for in situ delivery of the β-galactosidase gene to auxiliary liver transplant in a rat model.Methods.The BAG vector, which was shown to be effective in genetic transduction of cultured NIH/3T3 cells, was produced in a Ψ2 packaging cell and later amplified in a selected PA317 clone. Hepatocyte replication was induced by one-third hepatectomy of the donor liver, and the procedure was followed by auxiliary partial liver transplantation. Twenty-four hours after hepatic induction or transplantation, viral supernatant at 37°C was perfused into the liver graft via the portal vein during a temporary occlusion of the graft portal vein.Results.All animals survived the transplantation procedures and were killed at specified time intervals. Histochemical staining of the liver graft specimens indicated the expression of β-galactosidase in the gene transferred group but not in the control animals. As demonstrated by polymerase chain reaction assay, the proviral β-galactosidase sequence was present in the graft specimens, but absent from all other tissues tested.Conclusions.In short, the retrovirus BAG vector can be useful for in situ delivery of foreign genes to liver graft in transplantation and other clinical settings, providing a simple, consistent, and reliable alternative in hepatic gene therapy experiments.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.We have recently shown that lethally irradiated normal strains of mice and rats, reconstituted with bone marrow from severe combined immune deficiency (SCID) mice, can be engrafted with human peripheral blood mononuclear cells (PBMC).Methods.The feasibility of transplanting human renal tissue under the kidney capsule of the SCID/Lewis and SCID/nude radiation chimera and the effects of intraperitoneal infusion of allogeneic human PBMC on the human renal implants were investigated by histology, electron microscopy, immunohistochemistry, and fluorescence-activated cell sorter analysis.Results.Sequential evaluation of the human renal implants from 10 days to 2 months after transplantation showed that human parenchymal elements survive in the implants up to 2 months after transplantation. The overall architecture of the transplanted kidney tissue and the normal structure of individual cells in the glomeruli and tubuli were preserved. Infusion of allogeneic human PBMC after kidney implantation resulted in patchy cellular infiltrates, composed mainly of activated human T cells, and led to prompt rejection of the human renal tissue, whereas no signs of inflammation were observed in human renal implants of chimeric rats that did not receive human PBMC. Treatment with OKT3 antibody, anti-human CD25 antibody, or CTLA4Ig fusion protein in vivo ameliorated the rejection process.Conclusions.Human adult kidney fragments transplanted into SCID-like rats transiently retain competent parenchymal structures. When these grafts are combined with allogeneic human PBMC, acute cellular rejection develops. We suggest that this chimeric model might be useful for the investigation of the effects of experimental manipulation on the kinetics of the inflammatory response during human renal allograft rejection.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.Transplantation of human kidney tissue under the kidney capsule of immunodeficient animals (severe combined immunodeficiency [SCID]/Lewis and SCID/nude chimeric rats), and the subsequent intraperitoneal infusion of allogeneic human peripheral blood mononuclear cells (PBMC), results in a rapid and consistent human renal allograft rejection. We investigated the consequences of grafting human fetal kidney fragments instead of the adult tissue.Methods.The development of human fetal kidney tissue and its interaction with allogeneic human PBMC in chimeric rats were analyzed by histology, immunohistochemistry, and in situ hybridization.Results.We report successful establishment of human fetal kidney to SCID/Lewis and SCID/nude chimeric rats. The intrarenal human fetal renal implants displayed rapid growth and maintained numerous developing glomeruli and tubular structures up to 4 months after transplantation. In contrast to the adult human kidney, infusion of allogeneic human PBMC resulted in either minimal human T-cell infiltration or abundant nonrejecting T-cell infiltrates, characterized by a reduced number of T cells of the CD45RO+or HLA-DR+subsets, both leading to less tissue destruction as well as to continued growth of the human fetal renal tissue. This observation was found to be related to the reduced protein expression of tissue HLA class I and II, intercellular adhesion molecule 1, and vascular adhesion molecule 1 in the fetal grafts compared with the adult grafts. Lack of tissue expression of Fas ligand in the fetal grafts suggests that the latter does not contribute to the delayed rejection of human fetal kidneys.Conclusions.Our model should be useful for the study of human fetal renal development and the human alloresponse against fetal tissue.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.Induction of tolerance with anti-CD4 has mainly focused on monoclonal antibodies (mAbs) that deplete CD4+T cells. In this study, the mechanisms by which nondepleting anti-CD4 mAbs induce tolerance in the Dark Agouti to PVG rat heart graft model were examined.Methods.Five anti-CD4 mAbs were tested. Immunohistology and cytokine mRNA profiles were analyzed within grafts. Effects of combining anti-CD4 therapy with alloantibody (alloAb), interleukin (IL)-4, and anti-IL-4 mAb were also examined.Results.All mAbs tested induced indefinite graft survival (>150 days), with blocking of alloAb production. Exogenous alloAb did not restore rejection. Similar T cell receptor αβ+, CD8+, IL-2 receptor+T cell, macrophage, and natural killer cell infiltration and comparable MHC II and intercellular adhesion molecule-1 levels were seen in rejecting and tolerant grafts. mRNA for IL-2, interferon-γ, lymphotoxin, tumor necrosis factor-α, transforming growth factor-β, cytolysin, and granzyme-A/B was comparable, although inducible nitric oxide synthase was slightly reduced in tolerant grafts. IL-4 and IL-5 were significantly reduced in tolerant grafts, although IL-6, IL-10, and IL-13 levels were similar; this was consistent with partial T helper (Th)2 response inhibition, which was also manifested by inhibited alloAb. The combination of alloAb, IL-4, or anti-IL-4 mAb with anti-CD4 did not prevent tolerance induction.Conclusions.This study demonstrated that anti-CD4 mAb therapy did not inhibit activation and infiltration of Th1 and CD8+effector T cells. Preferential induction of Th2 responses, especially IL-4, was not essential for the induction of tolerance. Our studies also found no evidence to support induction of anergy or transforming growth factor-β as mechanisms of tolerance induction. These results question whether IL-4 is required for induction of transplantation tolerance.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID

摘要:

Background.We describe a 35-year-old male type 1 diabetic who underwent a cadaveric combined kidney-bladder-drained pancreas transplant with a duodenocystostomy for exocrine drainage who developed a large pelvic pseudocyst associated with a dilated pancreatic duct and an elevated serum amylase level.Methods.Due to the risk of surgical revision and the possibility of creating a cutaneous fistula with conventional percutaneous drainage, a pseudocyst-to-bladder drainage was performed. After the procedure, the catheter was capped to allow drainage of the pancreatic secretions into the bladder.Results.After drainage, the patient's serum amylase and lipase normalized along with resolution of the pseudocyst. The tube was removed after 19 weeks with no evidence of a recurrent pseudocyst and a normal serum amylase level.Conclusion.The percutaneous pseudocyst-cystostomy obviated the need for surgical revision of the exocrine gland drainage and thus eliminated the morbidity and the potential risk of graft loss associated with such surgery.

ISSN:0041-1337    

出版商:OVID    

年代:1997

数据来源: OVID