紫杉醇对大鼠移植动脉内膜增生及硬化的抑制作用

目的观察紫杉醇对同种大鼠移植动脉的影响,探讨紫杉醇对移植物动脉硬化的抑制作用及机制。方法以W istar大鼠为受者,SD大鼠为供者,按供鼠、受鼠不同分为3组,每组8对:同系对照组W istar大鼠接受W istar大鼠的胸腹主动脉移植;同种对照组W istar大鼠接受SD大鼠的胸腹主动脉移植;同种实验组W istar大鼠接受SD大鼠的胸腹主动脉移植,术后1~14 d腹腔注射紫杉醇2 mg.kg-1.d-1。两个对照组每日腹腔注射相同体积的生理盐水。术后30 d,取出移植动脉,进行病理学观察,测出管腔面积和内膜截面积,计算再狭窄率,用免疫组织化学方法测定增殖细胞核抗原(PCNA)的表达。结果同种实验组移植动脉内膜厚度、内膜PCNA表达情况均较同种对照组明显减少,外膜炎症细胞浸润程度、管腔再狭窄率均较同种对照组降低,差异有统计学意义。结论紫杉醇能有效抑制同种大鼠移植动脉内膜增生,防止移植物动脉硬化,其作用机制可能与抑制血管平滑肌细胞增殖和减轻对移植物的免疫排斥反应有关。     

Analysis of parathyroid graft rejection suggests alloantigen-specific production of nitric oxide by iNOS-positive intragraft macrophages

BackgroundDuring acute rejection of organ or tissue allografts T cells and macrophages are dominant infiltrating cells. CD4-positive T cells are important for the induction of allograft rejection and macrophages are important effector cells mediating cytotoxicity via production of nitric oxide (NO) by the inducible NO-synthase (iNOS). In the present study we analysed whether the destruction of primarily nonvascularised parathyroid allografts is also mediated by iNOS-positive macrophages.MethodsHypocalcaemic Lewis rats received parathyroid isografts (from Lewis donors) and allografts (from Wistar Furth donors), respectively, under the kidney capsule. Levels of serum calcium above 2 mmol/L correlated with normal parathyroid function and below 2 mmol/L with parathyroid rejection. Accelerated parathyroid allograft rejection was induced by immunisation of Lewis recipients with the allogeneic peptide P1.ResultsDetermination of serum calcium levels is a useful parameter to control parathyroid graft function, and therefore to determine allograft rejection. Macrophages positive for both major histocompatibility complex (MHC) class II molecules and costimulatory molecules accumulated in iso- and allografts, but iNOS-positive macrophages were only detectable in allografts in the presence of activated CD4-positive T cells. These results confirm a cooperation between activated T cells and intragraft macrophages to induce macrophage iNOS expression. Recipients immunised with the allogeneic peptide P1 demonstrated accelerated rejection of allografts (mean ± SD: 9.2 ± 0.9 days) in contrast to nonimmunised animals (mean ± SD: 15.8 ± 1.8 days). Allografts of P1-immunised animals were infiltrated faster by activated CD4-positve T cells and, in addition, the infiltrates of iNOS-positive macrophages were stronger than those in allografts of nonimmunised animals.ConclusionsIntragraft iNOS-positive macrophages seem to be able to produce cytotoxic NO involved in the killing of allogeneic cells during the alloimmune response against primarily nonvascularised parathyroid organ grafts. Infiltrates of iNOS-negative macrophages found in parathyroid isografts were caused by antigen-independent inflammation triggered by surgically induced injury. The absence of activated T cells in isografts and their presence in allografts underlines their importance in inducing macrophage iNOS expression.     

Experimental graft arteriosclerosis. I. The Lewis-to-F-344 allograft model.

Progressive graft arteriosclerosis is responsible for the majority of late deaths occurring in cardiac transplant recipients. In order to define a model of this disease in the rat, we exchanged heterotopic cardiac allografts between MHC-compatible inbred strains. Lewis rats served as donors and F-344 rats as recipients. Twenty allografts were followed by daily palpation and removed at the time of terminal rejection or on the 120th postoperative day for pathologic study. Sixteen allografts (80%) survived at least three weeks, and five allografts (25%) survived indefinitely. The majority of arteries (greater than 90%) examined demonstrated significant intimal disease; histologic findings in lesions in allografts rejecting at early time points included intense mononuclear cell infiltration of the intima, while lesions in long-term-surviving allografts demonstrated fibrous intimal thickening, which is characteristic of graft arteriosclerosis seen clinically. A limited course of cyclosporine therapy in F-344 recipients increased the incidence of indefinite allograft survival from 25% to 86%, and was associated with a modest reduction in the amount of intimal disease observed. These results suggest that this model should be useful in future studies regarding the pathogenesis and therapy of cardiac graft arteriosclerosis.     

Cold ischemic injury,aortic allograft vasculopathy,and pro-inflammatory cytokine expression

BACKGROUND: The aim of this study was to understand the role of ischemic preservation injury and pro-inflammatory cytokine expression in the progression of allograft vasculopathy. METHODS: Using the rat aortic transplant model, grafts were stored at 4 degrees C for either 1 or 24 h. Graft vasculopathy was assessed at 4 and 8 weeks after transplantation. Intra-graft cytokine expression was measured at days 1, 3 and, 7 after transplantation. RESULTS: At 4 weeks, intimal hyperplasia of allografts was greater than isografts (P<0.05). At 8 weeks, all groups had an increase in graft vascular disease compared to the 4-week groups (P<0.05). Allografts preserved for 24 h displayed a greater degree of vessel-wall reaction than both isograft groups and allografts stored for 1 h (P<0.05). An increased expression of the cytokines, TNF-alpha, TGF-beta, IL-2, INF-gamma, IL-1, and IL-6 was noted in the allografts stored for 24 h compared to similarly treated isografts (P<0.05). CONCLUSIONS: Prolonged ischemic preservation injury induced vascular disease in both isografts and allografts. The vessel wall reaction increased over time and was greater in allografts than isografts. The enhanced expression of T cell- and macrophage associated cytokines in allografts compared to isografts, suggested that early pro-inflammatory cytokine expression played an important role in progression of allograft vasculopathy.     

Low molecular weight fucoidan prevents neointimal hyperplasia after aortic allografting

BACKGROUND: Fucoidan, a new low molecular weight sulfated polysaccharide (LMWF), has previously been shown to mobilize bone marrow-derived progenitors cells via stimulation of stromal derived factor (SDF)-1 release. Mobilized progenitor cells have been suggested to repair intimal lesions after immune-mediated endothelial injury and thus prevent intimal proliferation. The aim of this study was to evaluate the effect of LMWF treatment in a rat aortic allograft model of transplant arteriosclerosis (TA). METHODS: Aortic grafts were performed in Brown Norway (BN, donor) and Lewis (Lew, recipient) rats. The recipient rats were treated with LMWF (5 mg/kg/day) and sacrificed at 30 days. To determine the role of SDF-1 in mediating the effects of LMWF, a specific inhibitor of the SDF-1 receptor CXCR4, AMD 3100 (20 microg/kg/day), was used. The grafted segments were evaluated by morphometric (histochemical) analyses. RESULTS: Untreated aortic allografts exhibited severe intimal proliferation, indicative of TA. In contrast, LMWF treatment significantly prevented allograft intimal proliferation as compared with controls (5.7+/-3 vs. 66.2+/-6 microm, P<0.01) and permitted a normalization of the intima/media ratio (0.1+/-0.1 vs. 1.7+/-0.3, P<0.01). Further, LMWF treatment stimulated allograft reendothelialization, as evidenced by strong intimal endothelial nitric oxide synthase antibody and CD31 signals. Unexpectedly, AMD treatment failed to prevent the protective effect of LMWF on intimal thickening and AMD treatment alone was found to reduced intimal proliferation in allografts. CONCLUSIONS: We found that LMWF treatment reduced intimal thickness and induced the presence of an endothelial cell lining in the vascular graft at 30 days. Our findings may suggest a novel therapeutic strategy in the prevention of TA.     

Prevention of GVHD and graft rejection by a new S1P receptor agonist, W-061, in rat small bowel transplantation

BackgroundIn small bowel transplantation (SBTx), inhibition of both graft-versus-host disease (GVHD) and allograft rejection is necessary.MethodsWe investigated the potency of a new sphingosine-1-phosphate receptor agonist, W-061, for these two immune responses in SBTx. W-061 has a completely different molecular structure from FTY720. Heterotopic SBTx was performed from Wistar-Furth (WF) into (WF × ACI) F1 rats as a GVHD model or F1 to WF rats as a rejection model. Recipients were orally given 3 mg/kg/day W-061 for 14 days after SBTx. Recipient survival, body weight, histopathology, lymphocyte subpopulations, and the cytokine profile were evaluated.ResultsW-061 treatment significantly prolonged graft survival over 100 days in four out of six recipients in the GVHD group and over 60 days in three out of six recipients in the rejection group. W-061 strongly inhibited GVHD and rejection as seen histopathologically in comparison with untreated control rats. W-061 caused a significant reduction in donor-derived T cells in target organs and infiltrating T cells in allografts by promoting these cells to home into the secondary lymphoid tissues and sequestrating those cells there. W-061 significantly decreased production of interferon-γ in target organs and allografts.ConclusionTherefore, these data suggest that W-061 has considerable potential as a new therapeutic immunosuppressant in patients with SBTx.     

Cell-free arterial grafts: Morphologic characteristics of aortic isografts,allografts, and xenografts in rats

Purpose: Chronic rejection of arterial allografts and xenografts results in arterial wall dilation and rupture, making them unsuitable for long-term arterial replacement in vascular surgery. In the arterial wall, as in other organs, the cells probably carry major antigenic determinants. Arterial wall cellular components can be removed by detergent treatment to produce a graftable matrix tube.Methods: We compared the patency and macroscopic and microscopic morphologic changes that occurred in sodium dodecyl sulfate (SDS) – treated and untreated arterial isografts, allografts, and xenografts 2 months after implantation in rats. We quantified elastin, collagen, and nuclear density in the three layers of the graft wall (intima, media, and adventitia) by morphometric methods. The SDS treatment removed endothelial and smooth muscle cells and cells in the adventitia but preserved elastin and collagen extracellular matrix.Results: All arterial xenografts, whether SDS treated or untreated, were aneurysmal 2 months after grafting, with loss of the medial cellular and extracellular components. In allografts, SDS treatment prevented dilation, reduced adventitial inflammatory infiltration, and preserved medial elastin. The SDS-treated allografts had an evenly distributed, noninflammatory intimal thickening that was richer in elastin fibers than that in untreated allografts.Conclusions: These results suggest an interspecies, but not an intraspecies, graft antigenicity of arterial extracellular matrix. The SDS treatment prevented chronic rejection of the arterial allograft and led to the proliferation of an elastin-rich and adapted intima. (J VASC SURG 1994;19:446-56.)     

受体细胞参与移植动脉内膜增生的研究

目的研究大鼠移植动脉新生内膜细胞Sty基因的表达，探讨受体细胞在移植动脉内膜增生中的作用。方法建立大鼠腹主动脉移植模型，分为4组：雌雄同系移植组、雌性异系移植组、雄性异系移植组、雌雄异系移植组。移植术后10周时，取移植动脉标本，进行病理组织学观察，测量其内膜厚度和中膜厚度，分析移植动脉内膜增生情况；采用显微切割技术收集新生内膜细胞，用PCR方法检测Sry基因的表达。分析新生内膜细胞与受体细胞的关系。结果异系移植组移植动脉内膜显著增生，动脉壁内膜厚度及内膜／中膜厚度比均显著高于同系移植组（P〈0．01）；而同性或异性异系移植组之间差异无统计学意义（P〉0．05）。PCR分析显示，雄性异系移植组和雌雄异系移植组在242bp处均有1条特异性扩增条带，而雌性异系移植组则无相应的核酸扩增条带。结论受体细胞作为移植物血管新生内膜细胞的来源，参与移植动脉内膜增生及移植物动脉硬化。     

Development of a combined cardiac and aortic transplant model to investigate the development of transplant arteriosclerosis in the mouse.

BACKGROUND: The degree of transplant arteriosclerosis in murine cardiac allografts is difficult to assess. Aortic allografts represent an alternative model for evaluating the impact of novel transplant strategies on transplant arteriosclerosis in which the vascular changes can be quantified easily. However, it remains controversial as to whether vascular lesions seen in this model are equivalent to those that develop in solid-organ transplants. The aim of this study was to develop a model of combined cardiac and aortic transplantation to allow more precise quantification of transplant arteriosclerosis and to establish a correlation between the lesions that develop in the 2 types of graft. METHODS: CBA (H2(k)) recipients received a C57BL/10 (H2(b)) cervical cardiac allograft on Day 0 and a C57BL/10 (H2(b)) abdominal aortic allograft on Day 1. Recipients were treated with anti-CD154 mAb (MR1) on Days 0, 2, and 4. We performed histology and morphometric measurements for both grafts 30 days after transplantation. RESULTS: We observed significant intimal proliferation in both the cervical cardiac and abdominal aortic allografts from recipients treated with anti-CD154 mAb (heart, 64% +/- 9%; aorta, 67% +/- 8%; n = 5). Abdominal aortic grafts transplanted alone into anti-CD154-treated recipients developed a degree of transplant arteriosclerosis equivalent to that seen in the aortic grafts of the combined group (aorta alone, 68% +/- 9%, vs aorta + heart, 67% +/- 8%; n = 5). CONCLUSIONS: This combined cardiac and aortic transplant model permitted quantitative assessment of transplant arteriosclerosis while monitoring graft survival by cardiac palpation. Furthermore, development of transplant arteriosclerosis was equivalent in abdominal aortic allografts either in the presence or absence of an additional solid- organ transplant.     

Prevention of cardiac allograft arteriosclerosis using antisense proliferating-cell nuclear antigen oligonucleotide

Cardiac allograft arteriosclerosis limits long-term survival of recipients and is characterized by intimal thickening comprised of proliferative smooth muscle cells. Proliferating-cell nuclear antigen (PCNA) plays a pivotal role in the cell cycle regulatory genes involved in smooth muscle cell proliferation. To test the hypothesis that antisense PCNA oligodeoxynucleotide (ODN) can prevent allograft arterial intimal hyperplasia, we performed single intraluminal delivery of the antisense or sense PCNA ODN or no transfer into murine cardiac allografts. DBA/2 murine hearts were transfected and transplanted into B10.D2 mice; the allografts were harvested 4 weeks later. Severe intimal thickening with enhanced expression of PCNA was observed in untransfected and sense PCNA ODN-treated allografts, whereas antisense PCNA ODN prevented neointimal formation.     

Chronic rejection of rat aortic allograft: II. Administration of cyclosporin induces accelerated allograft arteriosclerosis

Abstract. Rat aortic allografts immunosuppressed with cyclosporin - but not with azathioprine or steroids - develop an early inflammatory lesion in the subendothelial space. This "endothelialitis" is followed by an influx of proliferating smooth muscle cells into the intima, resulting in intimal thickening and accelerated arteriosclerosis. Administration of azathioprine and steroids largely ameliorates the development of the accelerated lesion. Similar endothelialitis and accelerated arteriosclerosis have been observed previously in the autopsy material of cardiac transplant recipients. Our results confirm the suggestion that the development of accelerated allograft arteriosclerosis is most likely linked to cyclosporin administration.     

Injury of the coronary endothelium at implantation increases endothelial dysfunction and intimal hyperplasia after heart transplantation.

BACKGROUND: Coronary endothelial dysfunction occurs early after heart transplantation and predicts the development of intimal thickening characteristic of cardiac allograft vasculopathy. OBJECTIVES: To assess the effects of removal of the endothelium by balloon injury of coronary arteries of allografts without rupture of the internal elastic lamina at the time of implantation and on coronary endothelial dysfunction, and to assess the development of accelerated atherosclerosis after heart transplantation. METHODS: A porcine model of heterotopic heart transplantation with preoperative immunologic typing, enabling progressive rejection without immunosuppression, was used to study the effect of endothelial removal on these 2 end points. Endothelium-dependent relaxations of epicardial coronary arteries from allografts submitted to endothelial denudation after harvest, arteries from allografts not undergoing denudation, and native coronary arteries were compared 30 days after graft implantation by using standard organ chamber experiments. Intimal thickening was measured by light microscopy with a semiquantitative scale (0 to 4+ grading). RESULTS: Relaxations to serotonin and to bradykinin were significantly decreased in denuded arteries compared with nondenuded allograft arteries. There was a significant increase in the incidence of severe intimal hyperplasia in denuded arteries compared with nondenuded arteries, which were both significantly increased compared to native coronary arteries. CONCLUSIONS: Endothelial injury at implantation worsens the endothelial dysfunction as a result of rejection after heart transplantation and compounds the intimal thickening leading to cardic allograft vasculopathy. All efforts should be deployed to maintain a morphologically intact and functional endothelium at the time of graft implantation.     

Early and late chemokine production correlates with cellular recruitment in cardiac allograft vasculopathy

BACKGROUND: Cardiac allograft vasculopathy (CAV) remains the leading cause of late mortality in heart transplant recipients. Activated T lymphocytes and macrophages infiltrate the donor heart before vascular intimal thickening develops, but the specific mediators of mononuclear cell recruitment leading to CAV are unknown. Therefore, we sought to define the relationship between chemokine gene expression and production, T lymphocyte and macrophage recruitment, and intimal thickening in a murine model of CAV. METHODS: B10.A or B10.BR strain hearts were transplanted heterotopically into B10.BR mice. Recipients were killed at 1, 4, 7, 14, and 30 days. Donor hearts were assayed for chemokine gene expression with ribonuclease protection and for protein with ELISA. Intragraft cellular infiltration was defined immunohistochemically. Intimal thickening was quantitated morphometrically. RESULTS: Early and late patterns of intragraft chemokine expression associated with distinct cellular infiltration were identified. First, transient MIP-2 and MCP-1/JE production in isografts and allografts correlated with neutrophil and macrophage infiltration. MCP-1/JE production and macrophage infiltration was greater in allografts than isografts. Second, allografts demonstrated sustained lymphotactin, RANTES, and IP-10 expression, beginning at day 4, correlating with persistent macrophage and T lymphocyte infiltration. Intimal thickening became evident at 14 days. Isografts did not display the late pattern of sustained chemokine gene expression, cellular infiltration, or intimal thickening. CONCLUSIONS: Transient, early MIP-2, and MCP-1/JE production in isografts and allografts correlated with neutrophil and macrophage recruitment, and is likely related to ischemia-reperfusion. In allografts, the delayed induction of chemokines specific for macrophages and T lymphocytes correlated with mononuclear cell infiltration and preceded intimal thickening. This study thus demonstrates a dual pattern of chemokine induction correlating with intragraft mononuclear cell recruitment, associated with ischemia-reperfusion and CAV development. Chemokine-directed interventions may interfere with leukocyte trafficking and inhibit CAV development.     

缺血损伤诱导同品系大鼠腹主动脉移植硬化实验研究

目的 探索缺血损伤在同品系大鼠腹主动脉植硬化中的作用。方法 将９０只大鼠随机分为３组：Ａ组为同品系移植缺血小于３０分钟组;Ｂ组为同品系移植缺血４小时组;Ｃ组为异组移植缺血小于３０分钟组。于移植术后１５、３０及６０天以植入的腹主动脉进行光镜和电镜检查,应用ＭＩＡＳ－３００计算机图像分析系统自动测量移植腹主动脉管腔面积、内膜面积和中膜面积。结果 Ａ组术后６０天动脉内膜轻度增厚,但Ｂ组和Ｃ组怵后６０天均     

Attenuation of aortic graft arteriosclerosis by systemic administration of Allotrap peptide RDP58

There remains no treatment for chronic allograft rejection mainly manifested by progressive arteriosclerosis. We investigated the effect of Allotrap peptide RDP58 therapy on arteriosclerosis in an aortic allotransplant model. RDP58 was administered intraperitoneally at 0.1, 0.5, or 2.5 mg/kg, every other day after transplantation. RDP58 therapy markedly inhibited vascular intimal thickening, media necrosis, and adventitial cellular inflammation. The attenuation of arteriosclerosis was associated with the induction of heme oxygenase (HO)-1 expression, inhibition of TNF-alpha production in aortic allografts, as well as decreased specific complement-dependent cytotoxic antibodies in serum. RDP58 inhibited both smooth muscle cell (SMC) proliferation with an 80% inhibition at 100 microM without evidence of cytotoxicity and TNF-induced apoptosis of SMCs in a dose-dependent fashion. These data suggest that the suppressive effect of RDP58 on allograft arteriosclerosis is due to multiple actions of the peptide, including induction of HO-1, inhibition of TNF-alpha, and a direct effect on SMC proliferation.     

Prolonged cold preservation promotes the recipient's cell participating in neointima formation but delays the later graft arteriosclerosis in rat model

Chronic graft dysfunction is the greatest barrier to long-term graft survival, although the immediate outcome in organ transplantation has been greatly improved. Graft arteriosclerosis is a prominent feature of chronic graft dysfunction. Recipient progenitor cells have been shown to participate in neointimal development in graft arteriosclerosis. The present study investigated the role of recipient endothelial cells in the repair and remodeling after a cold preservation injury in an orthotopic cross-sex abdominal aortic allotransplantation model, namely female Wistar to male Sprague-Dawley rats. Grafts were preserved for 48 hours in 4 degrees C University of Wisconsin (UW) solution for a prolonged cold ischemia (PCI) group or preserved for <1 hour in the control group; or for <1 hour in the presence of feeding with cyclosporine (CyA). A direct in situ polymerase chain reaction (ISPCR) for the SRY gene showed SRY-marked endothelial and smooth muscle-like cells in neointima at 2 weeks in the PCI group, at 4 weeks in the control group, and rarely at 3 months in the CyA group. Staining by H&E showed the aortic graft intima to be thicker in the PCI than in the control group at 4 weeks, but thinning thereafter. The SRY-positive cells correlated with intimal thickness in the PCI and the control group (r = .801 and .825; P < .05 and <.05, respectively), but not in the CyA group (r = .247, P > .5). Our data suggest that prolonged cold preservation promotes recipient cell participation in graft arteriosclerosis after endothelium injury. The early neointimal formation via recipient cells incorporated into arteriosclerotic neointima may delay later intimal thickening. In the aortic allotransplantation model, prolonged cold ischemia may be beneficial for long-term graft survival due to early endothelial replacement. We hypothesize that controlled injury to the graft may serve as a new strategy for treatment of intimal thickening.     

Effect of a novel inducible nitric oxide synthase inhibitor in prevention of rat chronic aortic rejections

BACKGROUND: Cytotoxic nitric oxide (NO) is produced during ischemia-reperfusion injury and acute and chronic rejection in allografts by expression of inducible (i) NO synthase (NOS). Therefore, continuous inhibition of iNOS may prevent early graft dysfunction and immune injury (rejection) and consequently improve graft survival. FR260330 is a potent and selective inhibitor of iNOS activity that works by preventing iNOS monomers from dimerization. In this study, the authors evaluated the effect of FR260330 in prevention of chronic rejection in a model of rat aortic allografts. METHODS: Male Lewis (LEW, RT1l) rats received male ACI (RT1a) aorta allografts or LEW aorta isografts. Fourteen groups (n > or = 6) were involved in this study. FR260330, tacrolimus, or both were administered orally for 14 or 90 days, according to protocol. The degree of intimal proliferation of graft aorta was determined by a computerized image system. RESULTS: Both low and high doses of FR260330- or tacrolimus-treated grafts showed significantly decreased intima/(intima+media) ratios at day 90 compared with placebo controls. Combination therapy of low-dose FR260330 with low-dose tacrolimus produced a significant decrease of intima/(intima+media) ratios with intact endothelium compared with placebo controls. Anti-alpha-actin immunohistochemical staining demonstrated that one of the mechanisms of intimal proliferation is related to migration of vascular smooth muscle cells. CONCLUSIONS: A selective inhibitor of NOS, FR260330 plays a protective role in chronic aortic allograft rejection in the rat. Combination therapy of low-dose FR260330 with tacrolimus produces significant protection of immune injury and may serve to improve long-term graft survival and function.     

Chronic rejection of rat aortic allograft

Rat aortic allografts immunosuppressed with cyclosporin — but not with azathioprine or steroids — develop an early inflammatory lesion in the subendothelial space. This endothelialitis is followed by an influx of proliferating smooth muscle cells into the intima, resulting in intimal thickening and accelerated arteriosclerosis. Administration of azathioprine and steroids largely ameliorates the development of the accelerated lesion. Similar endothelialitis and accelerated arteriosclerosis have been observed previously in the autopsy material of cardiac transplant recipients. Our results confirm the suggestion that the development of accelerated allograft arteriosclerosis is most likely linked to cyclosporin administration.