摘要:

Background.Mycophenolate mofetil (MMF) is an inhibitor of purine nucleotide de novo synthesis leading to impaired proliferation of activated lymphocytes. Studies in animals show a synergistic effect of MMF and cyclosporine (CsA) in preventing acute graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation. We performed a pilot study evaluating the feasibility of the combined application of MMF and CsA as GVHD prophylaxis after allogeneic blood stem cell transplantation. Toxicity and the bioavailability of MMF in this setting were investigated.Methods.Fourteen patients who had received grafts from HLA-compatible siblings received 2 g of oral MMF from day 1 to 14 combined with intravenous CsA at 4 mg/kg starting at day -1. Plasma levels of mycophenolic acid (MPA) and its glucoronide were measured by high-performance liquid chromatography. Fifteen patients treated with a combination of CsA and methotrexate at the same institution were referred to as the control group.Results.Trilineage engraftment was achieved in all study and control patients. Acute GVHD ≥ grade II was observed in 46.5% and 60% of the study and control patients, respectively. No major differences in the rate of acute toxicities were detectable. The mean trough blood level of MPA in 10 patients was 0.28 µg/ml, and 5.7 µg/ml for MPA glucoronide. Reduced peak levels of MPA indicate a reduced absorption rate of MMF in the early posttransplant phase.Conclusions.The combined administration of MMF and CsA was shown to be feasible in patients after allogeneic blood stem cell transplantation. Because of the decreased bioavailability of MMF, dose-finding studies for an intravenous formulation are warranted.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.Sirolimus (rapamycin) is a new immunosuppressant that appears to be synergistic with cyclosporine in kidney transplantation, but with a different side-effect profile. This pilot study evaluated sirolimus in liver transplantation.Methods.Patients undergoind orthotopic liver transplantation for primary tumors(8), and later for nonmalignant disease(7), received one of three sirolimus-based immunosuppressive regimens. Protocol A comprised sirolimus, microemulsion cyclosporine (target whole blood concentration: 100 ng/ml), and prednisolone; protocol B omitted prednisolone; and protocol C was sirolimus alone. By 3 months after transplantation, all patients were receiving sirolimus as monotherapy.Results.Fifteen patients were treated with a follow-up 117-806 days. Rejection was more common on monotherapy than double therapy, and absent on triple therapy. The drug was generally well tolerated, with only three patients discontinuing sirolimus: one for hyperlipidemia, one for pneumocystis pneumonia, and one for inability to tolerate the taste of the drug. Two patients discontinued cyclosporine early, both as a result of neurological complications; they continued on sirolimus monotherapy. Five patients died; one suffered a cardiac arrest, and four died from sepsis in association with graft-versus-host disease, recurrent tumor, a paralyzed right hemidiaphragm, and primary nonfunction.Conclusions.Sirolimus combined with cyclosporine provided potent immunosuppression of liver allografts, and sirolimus monotherapy was adequate and well tolerated as maintenance therapy. Side effects of sirolimus over the short period of follow-up were uncommon and reversible with dose reduction or cessation of therapy.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.Long-term results after liver transplantation for hepatocellular carcinoma have been disappointing, largely because of the high recurrence rate. It is controversial whether the immunosuppressed state of the recipient contributes to this recurrence rate. We have developed a model in the rat system to examine the effect of immunosuppression on tumor recurrence after transplantation, as well as to evaluate other treatment strategies to decrease the recurrence rate.Methods.A 2-mm3nodule of Morris hepatoma 3924a was implanted intrahepatically at day 0. At postimplant day 16, the animals underwent syngeneic orthotopic liver transplantation. Two treatment groups were established. Group I received saline injections subcutaneously for 2 weeks, while group II received subcutaneous cyclosporine injections at 3 mg/kg/day for 14 days. Animal survival, tumor recurrence rate, and sites of recurrence and number of pulmonary nodules were recorded.Results.Overall survival rate was reduced in animals receiving cyclosporine. The mean survival time was 74.4 days (SEM 6.39 days) in saline-treated animals and 50.4 days (SEM 7.63 days) in the cyclosporine-treated animals. The proportion surviving in group 1 was 47% and in group 2 was 18%. This difference in survival was statistically significant (P=0.025). The incidence of pulmonary nodules was increased in the cyclosporine-treated animals, and tumor recurrence in extrapulmonary sites was seen only in the cyclosporine-treated animals.Conclusion.Results from this study suggest that cyclosporine has an adverse effect on tumor recurrence after transplantation. This model will be useful to further examine treatment strategies to improve the outcome of transplantation for hepatocellular carcinoma.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.Endothelin (ET)-1 may have a role in hepatic polymorphonuclear leukocyte infiltration as well as microcirculatory disturbance during hepatic ischemia-reperfusion (HIR) injury. This study was conducted to investigate the influence of ET-1 on the hepatic microcirculation after total HIR and to evaluate the effect of a nonselective ET receptor antagonist under these conditions.Methods.Male rats pretreated with either normal saline (NS group) or TAK-044, a nonselective ET receptor antagonist (TAK group), were subjected to 120 min of total hepatic ischemia with extracorporeal portosystemic shunting.Results.Plasma ET-1 levels increased significantly from 1 to 6 hr after reperfusion in the NS group when compared with the nonischemic control. In the early phase of reperfusion, the NS group showed significantly narrower sinusoids, lower hepatic tissue blood flow, a lower hepatic tissue oxy-hemoglobin concentration, and more hepatic neutrophil infiltration than the TAK group (P<0.05). Pretreatment with TAK-044 improved hepatic microcirculatory derangement, and resulted in significantly better 7-day survival (61.5%) with more bile production after reperfusion when compared with the NS group (P<0.01).Conclusions.The present study demonstrated that ET-1 is involved in the development of HIR injury by causing deterioration of the hepatic microcirculation. A nonselective ET receptor antagonist successfully ameliorated HIR injury through improvement of hepatic oxygenation and of the microcirculation along with reduced hepatic neutrophil infiltration.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.CTLA4 immunoglobulin (Ig)G that binds to B7 effectively inhibits the signaling of CD28/ CTLA4-B7 pathway and induces antigen specific T cell unresponsiveness in vitro and in vivo. Using CTLA4IgG, we examined induction of long-term graft survival and the mechanism of maintenance of tolerance in rat allogeneic small bowel transplantation.Methods.Small bowels of Brown-Norway rats (RT1n) were heterotopically transplanted into Lewis rats (RT11). Recipients were treated with an i.p. injection of either CTLA4IgG or control IgG for 7 days.Results.Long-term survival was observed in rats treated with CTLA4IgG, whereas control rats died within 16 days after transplantation. To examine whether a tolerant state was established in long-term survival rats, secondary transplantation was performed using small bowels of Brown-Norway rats or ACI (RT1b) rats. It was demonstrated that small bowels of Brown-Norway rats were accepted; however, those of ACI rats were rejected within 10 days. Serum concentrations of interleukin (IL)-4 were maintained at >50 µg/ml for 7 days after transplantation in rats treated with CTLA4IgG but <15 µg/ml in control rats. IL-2 concentration was reduced to half in CTLA4IgG-treated rats compared with that in control recipients. Serum IFN-γ in CTLA4IgG-treated recipients increased after transplantation and was not distinguishable from that of control recipients during the first 7 days after transplantation.ConclusionWe demonstrated that CTLA4IgG treatment alone for 7 days induced a long-term donor specific tolerance in rat allogeneic small bowel transplantation. The induction of long-term acceptance of small bowel allografts by CTLA4IgG is not caused by simply the shift of anti-alloimmune responses from Th1 to Th2 cytokine production.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.Antithrombin III (AT-III) is an anti-thrombotic agent with known anti-inflammatory properties that is also known to attenuate acute inflammation, prevent ischemia-reperfusion injury, and disseminated intravascular coagulation (DIC) associated with sepsis and endotoxemia. Here, we examined the ability of AT-III to modify parameters of acute inflammation in a highly histoincompatible model of rat lung allograft rejection (AR).Methods.After left single lung transplantations (BN→Lew), recipient animals were treated i.v. with 50 U/kg of human AT-III (low dose group), 500 U/kg of human AT-III (high dose group), or normal saline (control group) on days 2 and 4 posttransplant. All animals were sacrificed on day 6, and several pathological categories of acute inflammation related to AR were scored (0-4). The effect of AT-III on concanavalin A (Con A)-stimulated rat spleen cell proliferation was also examined.Results.The stage of AR, and the degrees of edema, hemorrhage, and necrosis were significantly reduced in the high dose group compared with the control group. AT-III significantly inhibited rat spleen cell proliferation in response to Con A, in a dose-dependent manner. Maximal inhibition was seen at 15 U/ml in culture. Identical inhibition of Con-A-stimulated cultures occurred in both serum free and serum-containing media, indicating that AT-III inhibition of Con-A-stimulated rat spleen cell proliferation is independent of its actions on thrombin.Conclusions.1) AT-III treatment significantly improves parameters of acute inflammation seen in a highly histoincompatible model of rat lung AR. 2) AT-III inhibits in vitro T cell proliferation to the potent mitogen Con A, suggesting that protease inhibition may inhibit T cell activation in vitro. 3). The beneficial effects of AT-III on parameters of lung AR relate to the anti-coagulant, anti-inflammatory, and possibly immunoregulatory actions of AT-III.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.We investigated the effect of γ-hydroxybutyrate (GHB) when added to the low-potassium University of Wisconsin (LPUW) solution used for the preservation of canine lung for 24 hr. We also examined the effect of pretreatment of donor and recipient dogs with GHB on lung function after transplantation.Methods.Two groups were investigated. In the LPUW group, donor lungs were flushed with LPUW solution without GHB. In the GHB group, donor and recipient dogs were pretreated with GHB, and donor lungs were flushed with LPUW containing GHB.Results.Posttransplant graft function was best in the GHB group. At 1 hr after reperfusion, PaO2in the GHB group (475.7±96.2 mmHg) was significantly higher than in the LPUW group (188.3±102.7 mmHg,P<0.05). Furthermore, the use of GHB resulted in a significant increase in lung compliance (28.3±6.5 ml/cm H2O) compared with LPUW group (21.5±2.8 ml/cm H2O).Conclusions.Our results suggest that GHB is potentially useful for functional improvement of hypothermically preserved canine lung allografts after reperfusion.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.Despite numerous advances in the areas of organ preservation, histocompatibility, and immunosuppression, chronic deterioration of organ allograft function, referred to as "chronic rejection," still remains the main obstacle to long-term graft survival. The common feature of chronic rejection is a concentric generalized graft arteriosclerosis associated with interstitial fibrosis that reflects an allogeneic injury to graft arteries, possibly worsened by other alloantigen-independent risk factors. The presence of the angiotensin I-converting enzyme (ACE) gene-deleted (D) allele has been associated, when in homozygosity, with increased risk of cardiovascular diseases and with an accelerated progression of organ damage in a variety of kidney diseases. In this study, we analyzed whether the insertion/deletion polymorphism of the ACE gene, because of its negative prognostic impact on cardiovascular and renal pathology, could have any influence on kidney graft survival in pediatric recipients.Methods.DNA was isolated from peripheral blood mononuclear cells from 146 pediatric dialysis patients (mean age: 12.9 years) who received a first kidney graft at our center between December 1985 and July 1997. To rule out any bias due to acute graft losses, only 119 patients who reached a minimum of 12 months of graft survival were considered for statistical analysis. The insertion/deletion polymorphism of the ACE gene was detected using a polymerase chain reaction technique with two flanking primers.Results.The results demonstrated that (i) the distribution of DD and non-DD (ID + II) genotypes was 36.1% (43 patients) and 63.8% (76 patients), respectively; (ii) actuarial graft survival at 7, 8, 9, and 10 years in patients with non-DD genotype was significantly higher than that in patients with DD genotype (7 years: 94.6% vs. 72.4%,P<0.05; 8 years: 94.6% vs. 62%,P<0.025; 9 years: 87.3% vs. 51.4%,P<0.025; 10 years: 76.3% vs. 25.7%,P<0.01).Conclusions.In conclusion, the above data indicate that DD genotype is associated in pediatric kidney graft recipients with a shorter long-term kidney graft survival and suggest a possible role of this genotype as a cofactor in the progression of nonimmunological injuries leading to chronic kidney graft failure.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.FK506 is a recently developed immunosuppressant that has been useful in improving the survival of transplanted organs. Among the numerous adverse side effects of FK506, thrombotic microangiopathy (TMA) stands out as an infrequent but severe complication.Methods.We report two cases of FK506-associated TMA and review the 19 previous reported cases.Results.From these 21 cases, the reported incidence of FK506-associated TMA is between 1% and 4.7%. It is more frequent in females, and the mean age at presentation is 47 years. Eighty-one percent of the cases occurred in patients with kidney allografts, and the remaining patients had liver, heart, or bone marrow transplants. Clinically, TMA was diagnosed at an average interval of 9.3 months from the time of transplantation. Patients may be asymptomatic or may present with the full-blown picture of hemolytic uremic syndrome. All patients had an elevated serum creatinine level but did not always show signs of hemolysis. Trough levels of FK506 were not predictive for the development of TMA, but generally a reduction of drug dose correlated with kidney function improvement and disappearance of the hemolytic picture. The renal allograft biopsy provided a conclusive diagnosis in all 17 cases in which this procedure was performed. Treatment, which mainly consisted of reduction or discontinuation of FK506, anticoagulation, and/or plasmapheresis with fresh-frozen plasma exchange, resolved TMA in most patients (57%). However, in one of these patients (5%), the graft was subsequently lost due to causes unrelated to TMA, such as acute or chronic rejection. Despite treatment, one patient (5%) lost the graft due to acute rejection and persistent TMA, and three other patients (14%) who had bone marrow, heart, and liver transplants, died of multiple organ failure, probably unrelated to TMA. In the remaining four patients (19%), response to treatment was not reported.Conclusions.TMA must be considered in organ transplant patients treated with FK506 whenever kidney function deteriorates, even in the absence of microangiopathic hemolytic anemia. Although TMA usually responds to treatment, it may, in rare cases, lead to loss of kidney function or even the patient's death.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Background.Historically, young children undergoing renal transplantation have lower allograft survival than adults, and potential causes of this are being addressed by the North American Pediatric Renal Transplant Cooperative Study through the National Institutes of Health-sponsored study Cooperative Clinical Trials in Pediatric Transplantation. Included in this study is evaluation of surveillance renal biopsies (SB) and clinically indicated biopsies (CB). Few data exist in children to identify the risk involved with renal transplant biopsies.Methods.Questionnaires were mailed to 21 participating centers asking for descriptions of adverse events associated with kidney biopsies, with choices limited to none, gross hematuria, perinephric hematoma, and other. Further clinical details were obtained from review of medical records of all patients with reported adverse events. Data were collected from 19 centers on 126 patients.Results.Eighty-six patients had undergone 212 biopsies (75 SB and 137 CB). Nine biopsy-related adverse events were reported (4.2%): three SB (4.0%) and six CB (4.4%). Gross hematuria was reported in six patients (2.8%): two SB (2.7%) and four CB (2.9%). A perinephric hematoma was reported in one patient. Two patients with intraperitoneal kidneys developed significant bleeding after biopsy and required transfusions and surgical exploration. No patient lost kidney function or required nephrectomy after biopsy. No difference was noted in adverse events between SB at day 5 or 12 versus CB.Conclusion.Evaluation of transplanted kidney tissue may provide important information for the care of the transplantation patient. This analysis suggests that transplanted kidney biopsies can be performed with minimal risks in pediatric patients.

ISSN:0041-1337    

出版商:OVID    

年代:1999

数据来源: OVID