急性排斥反应时Fractalkine及其受体在移植心脏中的表达

目的　探讨急性排斥反应过程中Fractalkine(FKN)及其受体CX3CR1在移植心脏局部表达的意义及环孢素A(CsA)对它们的影响。　方法　施行大鼠异位心脏移植术 ,移植大鼠分为 3组 ,每组 45只 ,对照组 5只。SD大鼠间的移植为同系移植组 (A组 ) ,Wistar至SD大鼠的移植分为未用CsA干预组 (B组 )及CsA干预组 (C组 ) ,健康SD大鼠为对照组。采用RT PCR方法检测排斥反应中移植心脏局部FKNmRNA的表达水平 ,免疫组化方法检测FKN和CX3CR1的蛋白表达水平。　结果FKNmRNA与蛋白在A组各时间点和对照组均呈低水平表达 ;在B组的表达变化与急性排斥反应的进程相关 ,术后第 7天FKNmRNA表达上调至峰值 (0 8± 0 2 6) ;C组应用CsA后 ,FKNmRNA表达峰值显著低于B组 (t=2 3 90 ,P <0 0 5 )。FKN和CX3CR1蛋白分别定位于移植心脏血管内皮细胞及间质浸润的单个核细胞中。　结论　急性排斥反应过程中 ,FKN及其受体CX3CR1表达上调 ,与移植物间质单个核细胞浸润密切相关 ;抑制FKN CX3CR1通路的活化可能是CsA发挥作用的又一分子免疫学机制     

Malononitrilamides and tacrolimus additively prevent acute rejection in rat cardiac allografts

The novel immunosuppressive agents malononitrilamides (MNA) 279 and 715 are derivatives of A77 1726, the primary metabolite of leflunomide. The effects of these agents have been previously demonstrated in rat skin and cardiac allo- and xenotransplant models. The aim of this study was to evaluate the combination of MNA and tacrolimus in a high-responder rat cardiac allotransplant model. Graft survival was evaluated following 10 days of post-transplant oral therapy of MNA or tacrolimus alone and the drugs combined in PVG recipients of DA grafts. An iso-effect curve of single and combined drugs was constructed. Histological changes in grafts were evaluated at 10 days. MNA (20 mg/kg) or tacrolimus (2.4 mg/kg) alone prolonged graft survival with median survival of 14 and 13.5 days, respectively. Combined therapy of MNA (10 mg/kg) and tacrolimus 1.6 mg/kg likewise resulted in a median survival of 13.25 days and an iso-effect curve for these doses was constructed. Another iso-effect curve for median graft survival of 18-19 days, including MNA (10 mg/kg) + tacrolimus (3.2 mg/kg) in combination, MNA (30 mg/kg) alone and tacrolimus (4.8 mg/kg) alone, was constructed and both isoboles showed a straight line, demonstrating additive effects (zero interaction). In addition, histological analysis of grafts confirmed the benefit of the drug combination. No additional toxicity was noted with combined therapy. Optimal doses of MNA or tacrolimus had comparative effects on graft survival and histological changes, and a combination of the two drugs was beneficial with respect to both these parameters. The iso-effect curves verified additive effects of the drug combination.     

Difference in cytokine production in acute and chronic rejection of rat lung allografts

Abstract  In Brown Norway to Lewis rat lung transplantation, short-term administration of cyclosporine produces permanent adoption of allografts; however, the adopted grafts show symptoms of chronic rejection. To clarify the difference in cytokine production in acute an chronic rejection of the allografts, an immu-nohistochemical study was performed. In acute rejection, positive cells for respective cytokines were observed in infiltrating cells, increasing in number as the days after transplantation passed, and reaching a maximum on the fifth day. The strongest reactivity was observed perivenously. In chronic rejection, TNF-α positive cells were observed in the perivascular and peribron-chial regions, especially around class II positive epithelia. The number of positive cells was, however, less than that in the vascular phase of acute rejection. Few cells were positive for IL-lβ, IFN-γ and, unexpectedly, for IL-4. These facts indicate the functional difference of infiltrating cells between acute and chronic rejection.     

Clonality analysis of T cells mediating acute and chronic rejection in kidney allografts

The clonality of T-cell populations mediating acute and chronic rejection (AR and CR, respectively) of kidney allografts was ascertained by investigating the diversity of TCRBV genes expressed by allograft-infiltrating T cells. Both oligoclonality and polyclonality cases were found in biopsy specimens of AR as well as CR. These results indicated that the T-cell clonality in each specimen did not correlate directly with the mode of rejection. When AR and CR specimens were compared, however, the CR specimen group was significantly more polyclonal (or less oligoclonal) than the AR group. This result may reflect the higher chance of epitope spreading in the more slowly progressing CR than in AR.     

Rosiglitazone suppresses cyclosporin-induced chronic transplant dysfunction and prolongs survival of rat cardiac allografts

BACKGROUND: The lack of effective treatment for chronic transplant dysfunction restricts the long-term survival of solid organ allografts. Peroxisome proliferator-activated receptor ligands can suppress vascular inflammation. The aim of this study was to analyze the effects of rosiglitazone on chronic transplant dysfunction in a rat cardiac transplant model. METHODS: Inbred male Fisher 344 (F344, RT1lvl) and Lewis (LEW, RT1(1)) rats were subjected to heterotopic abdominal heart transplantation according to standard procedures. Cyclosporine A was administered intraperitoneally to cover acute rejection, and rosiglitazone was administered orally by gavage daily from 3 days before the operation to the end of experiments. RESULTS: Rosiglitazone significantly prolonged the survival of cardiac allografts in rats (F344 to LEW) that had received a 10-day course of cyclosporin A compared to treatment with immunosuppressant alone. Analysis of allografts at 120 days posttransplantation showed that rosiglitazone reduced the inflammatory cell infiltrate in both the vessels and graft parenchyma as were neointimal formation, vascular occlusion, and fibrosis. Expression of transforming growth factor-beta and related proteins was less abundant after cyclosporin A/rosiglitazone treatment. CONCLUSIONS: The findings reported here demonstrate that rosiglitazone given under the cover of short-term treatment with cyclosporin A prolongs cardiac allograft survival and reduces the severity of chronic transplant dysfunction. This may be mediated in part through the downregulation of transforming growth factor-beta and related proteins. The combined effects of rosiglitazone and immunosuppressive drugs are potentially beneficial to patients receiving organ transplants.     

Small bowel allografts. Sequence of histologic changes in acute and chronic rejection

Using a rat model of accessory small bowel transplantation, the histologic sequence of both acute and chronic rejection in intestinal allograft rejection has been defined. Histologically, all allografts were normal for the first 5 postoperative days. Allografts with caval venous drainage were subject to acute rejection. By 6 to 7 days postoperatively, plasma cells and lymphocytes infiltrated the lamina propria of these grafts (phase I). By 8 to 9 days postoperatively, the cellular infiltration intensified and was associated with villous blunting and scattered epithelial sloughing (phase II). By the 10th day, complete mucosal destruction developed, with heavy transmural infiltration by lymphocytes, plasma cells, and polymorphonuclear leukocytes (phase III). This histologic end point of acute graft rejection was accompanied by death of the host. Grafts with portal venous drainage underwent a similar, although less rapid, sequence of histologic changes (phase I 6 to 9 days, phase II 10 to 13 days, phase III 13 or more days) resulting in graft fibrosis and encapsulation. Some variability was seen among different areas of a given circumferential cross section taken from grafts in phases I and II. Studying circumferential cross sections allowed correct classification into the appropriate phases.     

肝脏移植急性排异与慢性排异的临床和病理分析

目的研究肝脏移植急性排异和慢性排异的临床表现及病理改变。方法观察和分析了我院２例肝移植患者术后出现急性和／或慢性排异时的临床表现，实验室检查及病理所见。结果急性排异时．ＡＳＴ和ＡＬＴ升高十分显著，而ＴＢＩＬ相对低，病理学有三个主要特征；而慢性排异时，ＴＢＩＬ。升高非常明显，ＡＳＴ和ＡＬＴ相对低，病理学有两个主要特征。结论实验室检查和病理特征对于鉴别急、慢性排异具有重要意义。     

Chemokine and receptor-gene expression during early and late acute rejection episodes in human cardiac allografts

BACKGROUND: The expression levels of several chemokine genes in heart allografts correlate with histologic rejection grade. Potential molecular differences between early and late rejection (grade > or =2) episodes were examined by testing chemokine and receptor-gene expression. METHODS: Expression of inducible protein (IP)-10, monokine induced by IFN-gamma (Mig), interferon inducible-T cell alpha chemoattractant (I-TAC), regulated on activation normal T-cell expressed and secreted(RANTES), and their receptors CXCR3 and CCR5 was tested in 60 endomyocardial biopsies from 24 patients using quantitative (Taqman) real-time polymerase chain reaction (PCR). The biopsies were taken in the first 3 months or from the 9th to the 12th month following transplantation. RESULTS: IP-10, Mig, RANTES, CXCR3, and CCR5 expression levels were increased in the later versus earlier biopsies (P< or =0.01) despite no change in histologic rejection-grade status.CONCLUSION These results demonstrate significantly increased expression of T-cell chemoattractants in heart allografts during later rejection when compared with episodes occurring shortly after transplantation. The findings suggest increased intensity of inflammation in rejection occurring at later times posttransplant that are revealed by molecular analyses of the graft.     

Combined use of rapamycin and leflunomide in prevention of acute cardiac allografts rejection in rats

This study aimed to evaluate the role of combined use of rapamycin and leflunomide(Lef) on the prevention of acute allograft rejection in rats. After cardiac transplantations, rats were randomly divided into untreated group, rapamycin group, Lef group and rapamycin+Lef group. The drugs were given by gavage from day 0 to day 9 after transplantations. Graft survival time was observed. Some grafts were harvested for histopathological investigation on day 10 after transplantations. The levels of CD(4)(+) and CD(8)(+) T lymphocytes and the concentrations of interleukin 2(IL-2) and interferon (IFN)γ in peripheral blood were examined on day 10 after transplantations. At the same time, the body weight, the hepatic function, renal function and the haemoglobin of the recipients were also examined. The graft survival time of untreated group was 7.14 ± 1.07 days. Rapamycin group was 11.14 ± 1.35 days. Lef group was 11.29 ± 1.80 days. While in rapamycin+Lef group, the graft survival time was prolonged to 13.86 ± 1.57 days(P<0.05). Histological changes of the allografts in rapamycin+Lef group were much milder than either of the two single drug groups. The absolute number and the percentage of CD(4)(+) T lymphocytes in peripheral blood in rapamycin+Lef group were lower than those of rapamycin or Lef group on day 10 after transplantations(P<0.05), while the percentage of CD(8)(+) T lymphocytes in rapamycin+Lef group was higher than that of rapamycin or Lef group(P<0.05). The absolute number of CD(8)(+) T lymphocytes was not significantly different among rapamycin group, Lef group and rapamycin+Lef group. The levels of IL-2 and IFN-γ in rapamycin+Lef group were significantly lower than that of rapamycin group or Lef group(P<0.05). The body weight, the hepatic function, renal function and the haemoglobin were not significantly different among rapamycin group, Lef group and rapamycin+Lef group (P>0.05). Combined use of rapamycin and Lef had better effect on the prevention of acute cardiac allografts rejection in rats than monotherapy.