大鼠低温保存同种带瓣主动脉和肺动脉移植物免疫排异反应的研究

探讨同种移植物对宿主免疫状态的影响以及排异反应对移植物的作用。方法通过低温保存的大鼠同种异体带瓣主动脉和肺动脉异位移植的动物模型,观察同种移植后宿主体液和细胞免疫指标的变化,以及移植物的病理改变。结果低温保存同种带瓣管道移植后有明显的免疫排异反应发生,细胞和体液免疫参与免疫排异反应的过程;慢性免疫排异反应以细胞免疫为主。结论免疫排异反应导致移植血管内膜增厚、管壁钙化、狭窄和闭塞。     

血红素氧合酶-1基因治疗减缓移植物血管病及机制

目的 观察血红素氧合酶-1(HO-1)基因治疗减缓同种移植物血管病的效果,探讨其机制.方法 以BN-Lewis大鼠血管移植为对象,依据基因治疗方案分为4组:同系对照组、空白对照组、载体对照组、腺病毒介导的HO-1( AdHO-1)组.移植后2个月,观察各组移植物纤维化和内膜增生,检测T细胞(CD3+)、B细胞(CD45RA)和巨噬细胞(CD68+)浸润数量,逆转录-聚合酶链反应(RT-PCR)和Western blot检测移植物HO-1基因和蛋白的表达,酶联免疫吸附试验(ELISA)法检测受体血清白细胞介素(IL)-10的浓度.结果 同系对照组无移植物血管病表现,空白对照组和载体对照组大量纤维沉积,AdHO-1组纤维沉积轻微.血管内膜/(内膜+中膜)百分比4组分别为7.6％、81.4％、85.9％、15.9％.每400倍视野浸润细胞数4组分别为T细胞(9.2±1.6、92.3±11.6、89.6±17.8、39.3±10.1)、B细胞(3.6±1.1、72.6±11.8、66.6±10.9、30.6±9.9)、巨噬细胞(7.5±1.2、78.5 ±21.7、72.5 ±19.8、34.5±18.7).血清IL-10浓度4组分别为(50.2±20.1)、(40.2±11.1)、(38.6±19.3)、(481.2 ±69.1)ng/L.AdHO-1组与空白对照组和载体对照组间差异有统计学意义(P＜0.05).AdHO-1基因治疗增高了移植血管HO-1基因和蛋白的表达.结论 AdHO-1基因治疗减缓同种移植物血管病,移植物纤维化和内膜增生明显减轻.AdHO-1基因治疗下调了T细胞、B细胞和巨噬细胞在移植物中的浸润,增加了HO-1和IL-10的表达,IL-10-HO-1通路的活化可能是移植血管得到保护的重要原因.     

肾移植排斥反应移植物中基因表达的研究

移植肾急性排斥是同种异体肾脏移植主要的临床问题 ,是慢性移植肾失功能的主要危险因素。监测血清肌酐水平、应用免疫组织化学方法或病理检查来诊断急性排斥、预测慢性排斥的发生不是很敏感 ,也不是很可靠。目前 ,人们应用分子生物学的技术方法来研究试验动物移植物和临床病理组织标本中与排斥有关的基因及其表达产物来筛选标志性基因 ,有望对肾移植排斥反应做出早期诊断并预测其发生 ,进而为阐明移植物排斥的机理以及基因治疗指明方向     

肾移植排斥反应移植物中基因表达的研究

移植肾急性排斥是同种异体肾脏移植主要的临床问题，是慢性移植肾失功能的主要危险因素。监测血清肌酐水平、应用免疫组织化学方法或病理检查来诊断急性排斥、预测慢性排斥的发生不是很敏感，也不是很可靠。目前，人们应用分子生物学的技术方法来研究试验动物移植物和临床病理组织标本中与排斥有关的基因及其表达产物来筛选标志性基因，有望对肾移植排斥反应做出早期诊断并预测其发生，进而为阐明移植物排斥的机理以及基因治疗指明方向。     

大鼠心脏移植排斥反应时细胞间粘附分子-1的表达及霉酚酸酯对其的抑制作用

目的　探讨大鼠同种异位心脏移植排斥反应期间移植心组织细胞间粘附分子-1（ICAM-1）的表达及霉酚酸酯（MMF）对移植心ICAM-1表达和排斥反应的抑制作用。方法　建立大鼠心脏腹腔移植模型,设Wistar到Wistar大鼠的同系心脏移植对照组、SD大鼠到Wistar大鼠的同种移植组和同种移植MMF治疗组。采集移植心组织标本行免疫组织化学和组织病理学检查,应用多媒体彩色图文分析系统对移植心组织ICAM-1的表达进行定量检测。结果　对照组移植心组织ICAM-1表达较弱;同种移植组在排斥反应期间移植心组织毛细血管内皮细胞ICAM-1的表达强度和数量明显增加,且伴有大量淋巴细胞浸润;MMF治疗组移植心仅微弱表达ICAM-1,同时少有淋巴细胞浸润;检测移植心组织ICAM-1的表达改变比普通组织病理学检查可以提早2～3d发现排斥反应。结论　ICAM-1的表达水平与排斥反应的发生和发展有关;MMF能显著抑制移植心ICAM-1的表达和淋巴细胞的浸润,明显延长移植物的存活。     

大鼠心脏移植排斥反应时细胞间粘附分了—1的表达及霉酚酯对其的抑制作用

目的 探讨大鼠同种异位心脏移植排斥反应期间移植心组织细胞间粘附分子－1（ICAM－1）的表达霉酚酯酯（MMF）对移植心ICAM－1表达和排斥反应的抑制作用。方法 建立大鼠心脏腹腔移植模型。设Wistar 到Wistar大鼠的同系心脏移植对照组、SD大鼠到Wistar大鼠的同种移植组和同种移植MMF治疗组。采集移植心组织标本行免疫组织化学和组织病理学检查,应用多媒体彩色图文分析系统对移植心组织ICAM－1的表达进行定量检测。结果 对照组移植心组织ICAM－1表达较弱;同种移植组在排斥反应期间移植心组织毛细血管内皮细胞ICAM－1的表达强度和数量明显增加,且伴有大量淋巴细胞浸润;MMF治疗组移植心仅微弱表达ICAM－1,同时少有淋巴细胞浸润;检测移植心组织ICAM－1的表达改变比普通组织病理学检查可以提早2－3d发现排斥反应。结论 ICAM－1的表达水平与排斥反应的发生和发展有关;MMF能显著抑制移植心ICAM－1的表达和淋巴细胞的浸润,明显延长移植物的存活。     

大鼠同系与同种肾移植的慢性排斥反应机制的研究

目的　研究大鼠肾移植后非免疫因素在慢性排斥反应发病机制中的作用。方法　对双肾切除的大鼠进行原位同系和同种肾移植 ,并设自体移植对照组。移植术后连续 5 2周对各组的尿蛋白含量、组织形态学和免疫组织化学进行观察。结果　同系移植组 2 4周时尿蛋白逐渐增多 ,小血管周围和肾小球周围出现持续性的单核细胞浸润 ;32周时 ,小管萎缩加重 ,因中膜平滑肌增生而出现小叶间动脉和皮质动脉内膜肥厚病灶 ;5 2周时 ,>30 %的肾小球发生节段性或完全的硬化 ,且几乎所有的动脉出现管腔狭窄 ,小管萎缩与间质纤维化亦非常明显。同种移植组在 12周时即有 >30 %的肾小球硬化 ;32周时 >40 %的肾小球出现完全或节段性的硬化 ,并间质纤维化。同系和同种移植组与自体移植组比较 ,差异均有极显著性 (P <0 .0 1)。结论　非免疫因素引起的同系移植肾功能和形态的变化与同种移植肾慢性排斥反应的早期表现相似 ,对前者而言 ,移植肾的初期损害和有功能的肾组织量是慢性排斥反应发病机制中的重要因素。     

基因治疗在器官移植中的应用

免疫耐受的诱导、移植物慢性失功和异种供体组织、器官的使用[1] 是目前器官移植的 3个前沿研究热点。基因治疗具有解决这些问题的潜在能力 ,近年已用于防治对移植物的排斥反应及诱导对移植物的免疫耐受等研究。1.基因治疗预防同种异体移植物的急性排斥反应 :对一个即刻血管化的同种异体器官的免疫应答是Ｔ细胞依赖性的 ,且其排斥反应机制同时有细胞介导和抗体介导的效应器参与。基因治疗的应用 ,使人们有可能通过将参与此过程的因子转入移植物 ,来调节宿主直接针对移植物的免疫反应。Ｑｉｎ等[2 ] 首次进行了这一尝试 ,他们用逆转录病毒或…     

移植物转染血红素氧合酶-1基因抑制慢性移植物血管病

目的探讨移植物转染血红素氧合酶-1（HO-1）基因对慢性移植物血管病的影响。方法克隆HO-1基因，并构建含有HO-1基因的重组腺病毒载体（Ad-HO-1），实验分为4组：A组为同系移植对照组，供、受者均为Lewis大鼠，无特殊处理；B组为同种移植对照组，Lewis大鼠接受未经处理的BN大鼠胸主动脉移植；C组为同种移植空载体对照组，Lewis大鼠接受以空载体（不含HO-1基因）处理的BN大鼠的胸主动脉移植；D组为同种移植实验组，Lewis大鼠接受转染HO-1基因的BN大鼠的胸主动脉移植。于移植后60d取移植动脉，进行组织形态学观察，测量内膜厚度；免疫组化和逆转录聚合酶链反应检测HO-1在移植动脉中的表达。结果A组移植动脉形态正常；B组、C组移植动脉呈移植物血管病表现，血管内膜显著增厚，D组移植动脉呈内膜炎改变，内膜厚度与B组、C组相比，差异有统计学意义（P〈0．01）。免疫组化及RT-PCR检测显示，与A组、B组和C组相比，D组移植动脉可以检测到HO-1基因及其蛋白表达。结论在移植血管中预先转染HO-1基因，能明显缓解移植动脉的纤维化进程以及内膜的增生，对慢性排斥反应所致的移植物血管病具有抑制作用。     

胰腺和肾脏在联合移植中排斥反应的比较

目的:比较胰腺和肾脏在联合移植中的排斥反应.方法:以大鼠同种异体胰肾联合移植为基础,对来自同一供体的联合移植的胰腺和肾脏排斥反应进行比较分析.结果:1.肾脏间质排斥反应出现较胰腺早.程度也较胰腺重,且以早期标本为著;2.胰肾血管排斥反应分级分布相似,无显著差异;3.胰肾间质排斥反应均早于血管出现,程度也较重     

Gene Transfer of Heme Oxygenase-1 and Carbon Monoxide Delivery Inhibit Chronic Rejection

The hallmark of chronic rejection is the occlusion of the artery lumen by intima hyperplasia as a consequence of leukocyte infiltration and vascular smooth muscle cell (VSMC) migration and proliferation. Heme oxygenase-1 (HO-1) is a tissue protective molecule which degrades heme into carbon monoxide (CO), free iron and biliverdin. We analyzed the effects of HO-1 gene transfer into the vessel wall using an adenoviral vector (AdHO-1) and of CO delivery in a model of chronic allogeneic aorta rejection in rats. Carbon monoxide treatment was achieved by a new pharmacological approach in transplantation using methylene chloride (MC), which releases CO after degradation. AdHO-1-mediated gene transfer into aorta endothelial cells (ECs) or CO delivery resulted in a significant reduction in intimal thickness compared to untreated or noncoding adenovirus-treated controls. Aortas transduced with AdHO-1 or treated with CO showed a reduction in the number of leukocytes as well as in the expression of adhesion molecules, costimulatory molecules and cytokines, with the gene transfer treatment displaying a more pronounced effect than the CO treatment. Conversely, CO inhibited VSMC accumulation in the intima more efficiently than AdHO-1 treatment. Gene transfer of HO-1 and pharmacological manipulation of CO are novel approaches to the analysis and treatment of chronic rejection.     

Chronic rejection in renal transplantation

With renal transplantation, chronic rejection is currently the most prevalent cause of late transplant failure. Clinically, chronic rejection presents as chronic transplant dysfunction, characterized by a slow loss of function, often in combination with hypertension and proteinuria. Transplant glomerulopathy and multilayering of the peritubular capillaries are highly characteristic for chronic rejection. Risk factors have been identified and include young recipient age, black race, presensitization, histoincompatibility, and acute rejection episodes, especially vascular rejection episodes and rejections that occur late after transplantation. Chronic rejection develops in grafts that undergo intermittent or persistent damage from cellular and humoral immune responses resulting from indirect recognition of alloantigens. Progression factors such as advanced donor age, renal dysfunction, hypertension, proteinuria, hyperlipidemia, and smoking play an important role. At the tissue level, senescence conditioned by ischemia/reperfusion may contribute to the development of chronic rejection. The most effective option to prevent renal failure from chronic rejection is to avoid graft injury from both immune and nonimmune mechanism together with nonnephrotoxic maintenance immunosuppression.     

Expression of A20 in the vessel wall of rat-kidney allografts correlates with protection from transplant arteriosclerosis

BACKGROUND: Chronic rejection with development of transplant arteriosclerosis is the major culprit involved in loss of kidney allografts. The allografts' fate was thought to depend on the intensity of the host immune responses and the potency of immunosuppressive regimens. Recent data suggests that grafts contribute to their own survival by way of up-regulation of "cytoprotective" genes. METHODS: We analyzed the expression of four cytoprotective genes, A20, Bcl-2, Bcl-x(L) and heme oxygenase (HO)-1, in three rat renal allograft models of chronic rejection: Fisher 344-Lewis (F344/Lew), Dark Agouti-Brown Norway (DA/BN), and DA-Wistar-Furth (WF). We chose these genes for their known anti-inflammatory and anti-apoptotic function in endothelial cells (EC) and the atheroprotective function of A20 in smooth muscle cells (SMC). RESULTS: Twenty-eight and 9 weeks following transplantation, F344/Lew and DA/BN transplants had stable graft function. Histopathologic analysis showed moderate tissue damage, minimal cellular infiltrates, and preserved vascular integrity correlating with high expression of A20 in SMC. Conversely, impaired allograft function in the DA/WF combination with substantial transplant arteriosclerosis was noted in 60% of the grafts correlating with absent or decreased A20 expression in EC and SMC. In all combinations, expression of HO-1, Bcl-2, and Bcl-x(L) colocalized with infiltrating cells and was not informative on the graft status. CONCLUSIONS: We demonstrate for the first time a strict correlation between A20 expression in the vessel and the absence of transplant arteriosclerosis in rat kidney-allograft models. This data is similar to data obtained in human kidney allografts and suggests that A20 may represent a novel therapeutic target for the prevention of chronic allograft rejection.     

Chronic Histological Damage in Early Indication Biopsies Is an Independent Risk Factor for Late Renal Allograft Failure

The impact of early histological lesions of renal allografts on long‐term graft survival remains unclear. We included all renal allograft recipients transplanted at a single center from 1991 to 2001 (N = 1197). All indication biopsies performed within the first year after transplantation were rescored according to the current Banff classification. Mean follow‐up time was 14.8 ± 2.80 years. In multivariate Cox proportional hazards analysis, arteriolar hyalinosis and transplant glomerulopathy were independently associated with death‐censored graft survival, adjusted for baseline demographic covariates. Arteriolar hyalinosis correlated with interstitial fibrosis, tubular atrophy, mesangial matrix increase, vascular intimal thickening and glomerulosclerosis. Clustering of the patients according to these chronic lesions, reflecting the global burden of chronic injury, associated better with long‐term graft survival than each of the chronic lesions separately. Early chronic histological damage was an independent risk factor for late graft loss, irrespective whether a specific, progressive disease was diagnosed or not, while T cell‐mediated rejection did not. We conclude that individual chronic lesions like arteriolar hyalinosis, tubular atrophy, interstitial fibrosis, glomerulosclerosis, mesangial matrix increase and vascular intimal thickening cannot be seen as individual entities. The global burden of early chronic histological damage within the first year after transplantation importantly affects the fate of the allografts.     

Peritransplant treatment with cobalt protoporphyrin attenuates chronic renal allograft rejection

Allogen-independent injury contributes to chronic rejection in renal allografts and heme oxygenase-1 (HO-1) has been shown to be protective in a number of settings. This study evaluated the effect of renal allograft recipient HO-1 up-regulation on chronic rejection in a rat model. Rat (F344 to Lewis) renal transplantation recipients were grouped: (i) cyclosporine (CsA) alone (0.75 mg/kg s.c. x 10 day; n = 5); (ii) CsA + low dose cobalt protoporphyrin (CoPP) an HO-1 inducer (0.5 mg/kg i.p. on days -5,0,5; n = 13) and (iii) CsA + high dose CoPP (5.0 mg/kg i.p. on days -5,0,5; n = 8). Renal function was assessed by serum creatinine levels on day 140. Histopathologic changes in allografts were graded. Morphometric analyses performed to objectively quantify the vascular changes and glomerulosclerosis. HO-1 expression quantified by Western blot and both HO-1 and endothelin (ET-1) localized using immunohistochemistry. Recipients treated with CsA + high dose CoPP had significantly decreased cortical scarring, vascular hyalinization and intimal thickness. They also had a significant, dose-dependent, reduction in luminal obliteration and glomerulosclerosis by morphometric analyses. This freedom from chronic rejection in recipients treated with CoPP translated into quiescent grafts at postoperative day 140 with immunostaining and Western blot demonstrating decreased level of HO-1 versus controls (P = 0.012). In summary, the peritransplant up-regulation of HO-1 in renal allograft recipients significantly attenuates chronic rejection in rat renal allografts by inhibiting transplant vasculopathy.     

Immunotoxin-treated rhesus monkeys: a model for renal allograft chronic rejection

BACKGROUND: Unlike acute and hyperacute rejection, chronic rejection (CR) still constitutes a poorly understood process. The onset is insidious, occurs in a period of months to years and, because the pathophysiology is not well understood, is untreatable. A reliable large-animal model for renal allograft CR is needed and has not been reported in the literature yet. METHODS: CR biopsy changes were studied in major histocompatibility complex-mismatched renal allografts performed in nine rhesus monkeys that received CD3 T-lymphocyte depletion therapy with immunotoxin on the day of the transplantation (n=7) or 7 days before transplant (n=2). RESULTS: Mean graft survival time was 613.77 days. Biopsy changes of CR were identified as soon as 84 days after transplant (mean, 336 days; range, 84-896 days). Most of the experimental animals had severe interstitial fibrosis, tubular atrophy, chronic transplant glomerulopathy, and chronic vascular rejection changes at the time of necropsy. A significant positive correlation between the severity of CR and the degree of CD68+ macrophage infiltrate of renal parenchyma and the degree of anemia and serum creatinine level elevations were also observed. CONCLUSIONS: Our findings are similar to those seen in human renal chronic allograft nephropathy, but in contrast, our model excludes all the nonimmune factors associated with chronic allograft nephropathy, including donor disease, injury from prolonged preservation, drug toxicity, and underlying recipient disease. Immunotoxin-treated rhesus monkeys emerge as an outstanding animal model for assisting us in understanding the pathophysiology of CR.     

Increased mRNA expression of transforming growth factor beta in the arterial wall of chronically rejected renal allografts in humans

INTRODUCTION: Transforming growth factor beta (TGF-beta) has an established role in interstitial damage of renal transplants during chronic rejection (CR). However, its involvement in transplant vasculopathy is not clear. The aim of the study was to assess TGF-beta gene expression in the walls of large-caliber arteries within chronically rejecting renal allografts. We evaluated associations between gene expression of this factor and intimal thickness or clinical data. MATERIAL AND METHODS: Renal artery samples of kidney allografts were obtained from 20 hemodialysis patients with end-stage renal graft disease due to CR, who were undergoing graftectomy. The control group included 32 hemodialysis patients with end-stage renal disease, undergoing nephrectomy due to autosomal dominant polycystic kidney disease (n = 12), chronic pyelonephritis (n = 13), or kidney limited tumor (n = 7). Gene expression of TGF-beta was measured using real-time PCR. RESULTS: TGF-beta mRNA expression was 3.25-fold higher in CR than in control patients (P < .001). Expression of mRNA for this cytokine was not influenced by the following factors: intimal thickness; age; serum cholesterol, triglycerides and glucose; BMI; graft survival; time of dialysis before transplantation; total ischemic time; immunosuppressive regimen; incidence of acute rejection episode; panel reactive antibodies; and period of dialysis before graftectomy. TGF-beta is involved in neointimal formation in CR.     

Loss of corticomedullary demarcation on magnetic resonance imaging: an index of biopsy-proven acute renal transplant dysfunction

A prospective study of 19 cadaveric renal allograft recipients with suspected graft rejection was undertaken to compare the histological findings of the renal transplant biopsy with the results of magnetic resonance imaging (MRI). All 19 patients underwent a biopsy of the transplant allograft. Biopsy results included acute cellular rejection, acute vascular rejection, chronic vascular rejection (CVR), and acute tubular necrosis (ATN). Recipients of cadaveric renal allografts with normal function served as controls. The control showed distinct corticomedullary demarcation (CMD) on T1-weighted imaging. In contrast, CMD was absent or diminished in all the patients with suspected allograft rejection. Unfortunately, the loss of CMD did not correlate with a specific biopsy diagnosis. Patients with biopsy evidence of acute and chronic rejection or ATN demonstrated loss of CMD with similar image patterns. In conclusion, MRI is capable of detecting renal allograft dysfunction, but does not permit the determination of a specific cause.     

Severe Renal Allograft Rejection Resulting from Lenalidomide Therapy for Multiple Myeloma: Case Report

Lenalidomide, a thalidomide analogue, is an immunomodulatory drug currently used as a chemotherapeutic agent in treating certain hematologic malignancies, including multiple myeloma. The antineoplastic effect of lenalidomide may be due to its ability to modulate different components of the immune system as well as its antiangiogenic, antiproliferative, and direct cytotoxic activity. Given its immunomodulatory effects, lenalidomide may potentially elicit unintended immune activity against allografts in solid organ transplant recipients. Here, we present a case of a renal transplant recipient who developed multiple myeloma after transplantation and was treated with the use of lenalidomide, which precipitated severe acute T-cell–mediated rejection. Lenalidomide was thought to be causative, and after cessation of the drug her renal function stabilized.