Leflunomide in renal transplantation

Leflunomide is a synthetic isoxazole-derivative drug that possesses both immunosuppressive and antiviral properties. Although its only US FDA-approved indication is for the treatment of rheumatoid arthritis, accumulating clinical experience in addition to animal study data makes it an appealing option for patients who are in need of reduction of immunosuppression in the setting of resistant cytomegalovirus infection or BK virus nephropathy, or in renal transplant recipients with chronic allograft dysfunction. While concern over adverse effects such as hepatotoxicity and hemolytic anemia cannot be ignored and there has yet to be a prospective randomized trial for its use in transplantation, its careful usage under close monitoring may provide the best chance for patients who risk allograft rejection during the time of immunosuppressive reduction as they attempt to eradicate BK virus or cytomegalovirus. At the present time, its use as a first-line agent in lieu of mycophenolate mofetil or sirolimus cannot be recommended.     

同种异体大鼠的主动脉移植后影响移植物钙化的因素分析

目的：探讨同种异体大鼠的主动脉移植后影响移植物钙化的因素。方法：研究分为2组，即异基因组和同基因组。异基因组中SD大鼠为供体，Wistar大鼠为受体；同基因组中受体和供体均为Wistar大鼠。两组再随机分为5个小组，每组8只，进行大鼠同种异体带瓣主动脉腹主动脉的异位移植。分别于术后2、4、8、12、16wk，以流式细胞术测定大鼠血液中CD25、CD71的表达。取出移植物，用原子火焰吸收法测定钙的含量，用光镜和电镜观察移植物的形态学变化，用免疫组化染色法测动脉壁CD40的表达：结果：（1）异基因组移植后各个时间点，CD40、CD25和CD71的表达均较同基因组高（P〈0．01）。异基因组CD25、CD71和CD40表达的高峰主要在移植后的早期（2～4wk），此后表达的水平逐渐下降，12nk后维持在低水平。（2）异基因组移植物的钙含量从移植后第4周开始升高，随着时间的推移逐渐升高，在12wk达到高峰，此后进入平台期。同基因组各个时间点的钙含量无差别（P〉0．05）。（3）移植后异基因组的移植物出现内皮细胞脱落和平滑肌细胞坏死。结论：同种瓣移植后移植物中的钙含量与免疫排斥反应关系密切；钙含量并不与时间完全呈正相关，在移植后4wk才开始钙化：随着时间的推移，钙含量逐渐升高，在12wk达到高峰，此后进入平台期。移植后不同时间点移植物中的钙含量并不与当时的免疫排斥反应的程度成正相关，二者互相影响。     

Circulating lymphocyte subsets in different clinical situations after renal transplantation

Phenotypic characterization of T and B lymphocytes allows the discrimination of functionally different subsets. Here, we questioned whether changes in peripheral lymphocyte subset distribution reflect specific clinical and histopathological entities after renal transplantation. Sixty-five renal transplant recipients with either histologically proven (sub)clinical acute rejection or chronic allograft dysfunction, or without abnormalities were studied for their peripheral lymphocyte subset composition and compared with 15 healthy control individuals. Naive, memory and effector CD8(+) T-cell counts were measured by staining for CD27, CD28 and CD45RO/RA. In addition, we studied the CD25(+) CD4(+) T-cell population for its composition regarding regulatory Foxp3(+) CD45RO(+) CD127(-) cells and activated CD45RO(+) CD127(+) cells. Naive, non-switched and switched memory B cells were defined by staining for IgD and CD27. We found a severe decrease in circulating effector-type CD8(+) T cells in recipients with chronic allograft dysfunction at 5 years after transplantation. Percentages of circulating CD25(+) CD127(low) CD4(+) regulatory T cells after transplantation were reduced, but we could not detect any change in the percentage of CD127(+) CD45RO(+) CD4(+) activated T cells in patients at any time or condition after renal transplantation. Regardless of clinical events, all renal transplant recipients showed decreased total B-cell counts and a more differentiated circulating B-cell pool than healthy individuals. The changes in lymphocyte subset distribution probably reflect the chronic antigenic stimulation that occurs in these transplant recipients. To determine the usefulness of lymphocyte subset-typing in clinical practice, large cohort studies are necessary.     

Heterogeneous expression of nestin in myofibroblasts of various human tissues

In this study we explored the distribution of nestin‐positive cells in extraneural human tissues with special reference to stromal myofibroblasts. Tissue microarrays were constructed from various tissues with normal histology and tissues with fibrosing disorders. Sections were immunostained for nestin, alpha‐smooth muscle actin (alpha‐SMA), desmin, vimentin, CD34, and other stromal markers. Nestin was expressed in the myoepithelium of the breast, podocytes of the renal glomerulus, and endothelial cells of most organs. Nestin was also expressed in the stroma of several organs, including the intestine, uterine cervix, and endometrium. Nestin‐positive fibroblast‐like cells appeared in the stroma of the kidney, pancreas, lung, and skin in fibrosing conditions. With the notable exception of endometrial stromal cells, most of these nestin‐positive stromal cells were alpha‐SMA‐positive. Interestingly, we observed a concomitant appearance of nestin‐ and CD34‐positive myofibroblasts under fibrosing conditions. Further investigation showed that nestin was expressed by stromal fibroblasts in cervical squamous cell carcinoma, but not in lung adenocarcinoma, pointing to heterogeneity of cancer stroma. In conclusion, nestin was expressed in variable proportions of stromal myofibroblasts in human tissues. The differential expression of nestin may indicate phenotypic and functional heterogeneity. Nestin‐positive myofibroblast may represent a relatively immature subpopulation of cells with multipotentiality.     

The role of replicative senescence in chronic allograft nephropathy

Strong evidence suggests that replicative senescence is involved in vivo because senescent cells have been detected in human tissues associated with physiological and pathological aging processes. Chronic allograft nephropathy (CAN) appears to be a major determinant of long-term survival in kidney transplantation. Several mechanisms are potentially involved; the aim of this study was to assess the impact of replicative senescence in CAN. Replicative senescent cells were detected on renal tissue cryosection using expression of a specific marker, senescence-associated beta-galactosidase (SA-beta-Gal) at pH 6. A total of 80 frozen renal samples (67 cases of CAN and 13 controls) were studied. To validate this marker, we measured in situ telomere length in cells expressing or not expressing SA-beta-Gal using a validated quantitative fluorescence in situ hybridization technique. The presence of senescent cells was correlated with clinicopathologic data. Telomere length was significantly lower in cells expressing SA-beta-Gal than in cells that did not. Replicative senescence was present in 45 out of 67 (67%) biopsy specimens and was significantly associated with the severity of CAN. No correlation with the notion of a previous episode of acute tubular necrosis, acute rejection, extrarenal epuration, duration of cold ischemia, and the delay between transplantation and biopsy was observed. However, the age of the donor, but not that of the recipient, was correlated with the occurrence of senescent cells. These results suggest that replicative senescence is a mechanism that might be involved in the development of CAN. The age of the donor appears to be the major determinant factor in replicative senescence.     

Importance of stromal determinants in the generation of dendritic and natural killer cells in the human spleen

Summary The interaction between stroma and blood cells in the human spleen has received little attention, despite their well-defined roles during blood cell development in bone marrow. We have reported previously that human spleen-derived fibroblasts display a differentiated myofibroblast phenotype and constitutively express a biologically active form of membrane interleukin (IL)-15 that can drive co-cultured CD34(+) blood cells to differentiate into activated natural killer (NK) cells. Here, we show that, in addition to NK cells, CD34/fibroblast co-cultures also yield myeloid CD1a(+)CD38(+)CD68(+)CD86(+) HLA-DR(+)CD14(-)CD80(-) dendritic cells (DCs) after 3-4 weeks in culture. We found that DC development depended on endogenously secreted stromal macrophage colony-stimulating factor (M-CSF) and CD40/CD40L interaction rather than on fibroblast- and CD34-derived membrane IL-15. CD1a(+) cells were necessary for co-produced NK cells to acquire lytic functions by a mechanism involving cell-to-cell contact and DC-derived IL-12. This study highlights the importance of spleen myofibroblasts in the in vitro generation of two distinct cell types (DC and NK cells) from the innate immune system and suggests that the human spleen is involved in the generation of NK cells from circulating progenitors.     

Survival of neural progenitor cells from the subventricular zone of the adult rat after transplantation into the host spinal cord of the same strain of adult rat

The subventricular zone (SVZ) of the lateral ventricle of the mammalian forebrain is the major site in which neural progenitor cells (NPC) persist in the adult brain. The NPC are located beneath ventricular ependymal cells and have the capacity to self-renew and continuously produce neurons and glial cells. We have shown previously that neurospheres can be obtained from the brain of deceased adult rats and that neurosphere cells survive after transplantation into the spinal cord. In the present study, we investigated whether fresh NPC from living adult rats can survive and be integrated into host tissues after transplantation into the adult rat spinal cord of the same strain. We used rats expressing transgenic green fluorescent protein (GFP) as a donor to identify the transplanted NPCs. The SVZ tissues were obtained from the striatal wall of the lateral ventricle of adult GFP-rats and were grafted into lesions of the spinal cord at the cervical level. Two to 3 weeks after grafting, NPC migrated through the host tissue 0.5-1 mm away from the implantation site, and were integrated into the white matter of the host spinal cord. Surviving NPC exhibited immunohistochemical phenotypes of astrocytes (glial fibrillary acidic protein), but not for neurons (alpha-tubulin III) or oligodendrocytes (Rip; Hybridoma Bank, Iowa City, IA, USA). Thus, NPC from the SVZ of adult rats can survive and differentiate into at least astrocytes, which can then be integrated into host tissue after transplantation into spinal cord lesions in the adult rat.     

Progression of renal allograft histology after renal transplantation in recurrent and nonrecurrent immunoglobulin A nephropathy

Little information is available regarding renal histology in cases of chronic allograft dysfunction and graft failure in patients with recurrent immunoglobulin A nephropathy. We compared 57 renal allograft biopsies of 44 patients with recurrent immunoglobulin A nephropathy to 43 biopsies of 33 patients without immunoglobulin A nephropathy recurrence. Clinical parameters such as patient demography and biopsy indications did not differ between the 2 groups, with the exception of time to biopsy. Renal allograft injury, which was assessed by semiquantitative scoring of glomerular, tubulointerstitial, and arteriolar changes, increased linearly over time after transplantation in both recurrent and nonrecurrent samples. Glomerular injuries were significantly correlated with tubulointerstitial injuries in both groups, but the correlation graph reflected an increasing gap in the degrees of tubulointerstitial injury between the 2 groups over time. The levels of glomerulosclerosis, mesangial proliferation, and crescent formation were significantly higher in recurrent samples, whereas the prevalence of chronic rejection was significantly higher in nonrecurrent samples. The presence of segmental sclerosis was associated with significant proteinuria in recurrent samples. Graft survival was better in recurrent immunoglobulin A nephropathy patients than in nonrecurrent patients (74.4% versus 51%) at 10 years after transplantation. In conclusion, slow and progressive glomerular injury is the major cause of long-term graft failure in patients with recurrent immunoglobulin A nephropathy. In contrast, rapidly increasing tubulointerstitial injury is responsible for graft failure in nonrecurrent patients.     

巢蛋白在阿霉素肾病模型大鼠肾组织中表达及霉酚酸酯的干预作用

背景：研究证明,足细胞损伤是产生肾小球性蛋白尿的重要机制。而关于足细胞内众多骨架蛋白如何互相调节维持足细胞特有的形态目前尚未完全了解,足细胞骨架的构建和重塑也成为蛋白尿发生机制的研究热点。 目的：构建阿霉素微小病变肾病大鼠模型,以霉酚酸酯进行干预,检测大鼠肾组织中巢蛋白(nestin)的表达。 方法：纳入雄性Wistar大鼠36只,随机均分为肾病模型组、霉酚酸酯组、正常组(n=12)。肾病模型组、霉酚酸酯组大鼠一次性尾静脉注射阿霉素进行造模,正常组尾静脉注射等量生理盐水。霉酚酸酯组大鼠于造模次日给予霉酚酸酯灌胃,20 mg/(kg•d),1次/d;其他两组大鼠每日给予等量生理盐水。各组分别于造模后14,21,28 d各处死4只大鼠,取肾皮质进行苏木精-伊红染色和免疫组化染色,观察大鼠肾组织病理学改变以及nestin表达情况。 结果与结论：正常组大鼠肾小球滤过膜结构完整,上皮细胞足突清晰;肾病模型组大鼠肾小球上皮细胞足突广泛融合,基底膜正常;霉酚酸酯组大鼠肾小球上皮细胞足突部分融合,但病变较轻。免疫组化结果提示从造模第14天开始,肾病模型组和霉酚酸酯组大鼠nestin表达明显增加,与正常组比较差异有显著性意义(P < 0.05);霉酚酸酯组大鼠nestin表达低于肾病模型组,差异有显著性意义(P < 0.05)。提示肾小球足细胞损伤时,足细胞内nestin表达增多,随病情加重而表达增高。霉酚酸酯可以减轻足细胞损伤,下调nestin的表达,维持足细胞的正常结构,达到延缓肾脏损害的目的。 中国组织工程研究杂志出版内容重点：肾移植;肝移植;移植;心脏移植;组织移植;皮肤移植;皮瓣移植;血管移植;器官移植;组织工程      

Expression of nestin in rat and human glomerular podocytes

Nestin is a neuroepithelial precursor cell marker expressed in a variety of human cell types during development. However, no information exists on the expression of nestin in mature glomeruli as well as during the glomerular development. Here, we examined nestin expression in rat and human glomerular tissues in quiescent states using RT-PCR and immunohistochemical methods. Nestin mRNA was detected in the rat glomeruli in parallel with its expression in developing rat brains. In the normal mature rat glomeruli, WT-1 positive cells expressed nestin. Co-expression of nestin and vimentin was observed in mature rat podocytes. Immunoelectron microscopy revealed nestin localization in the cell bodies and primary processes of podocytes. A similar expression pattern was observed for vimentin. In matured glomeruli, nestin was not expressed by mesangial and endothelial cells. In the newborn rat, early developing glomeruli (metanephric cap, metanephric vesicle, comma-shaped vesicle and S-shaped body phases) expressed nestin. In the capillary loop stage, Bowman's capsules also expressed nestin. Immunoelectron microscopy demonstrated that developing podocytes and endothelial cells in S-shaped phase glomeruli expressed nestin. Additionally, in immature glomeruli, the mesangial cells in capillary stage of glomerulus also expressed nexin. As in the rat, WT-1 positive cells in human glomeruli also expressed nestin and immunoelectron microscopy confirmed nestin expression in human glomerular podocytes. These results reveal that in normal condition nestin is expressed in several glomerular cell types at early stage of development and becomes confined to podocytes in mature glomeruli, thus implicating nestin in podocyte functions.     

Early recurrence of dense deposit disease with marked endocapillary proliferation after renal transplantation

Dense deposit disease (DDD), also known as type II membranoproliferative glomerulonephritis (MPGN), is characterized by the presence of continuous intramembranous dense deposits. At present, the histogenesis of DDD is not well known. Reported herein are two cases of early recurrence of DDD in renal allografts, with marked endocapillary proliferation. In case 1 the first allograft biopsy revealed electron-dense deposits mainly in the subendothelial and mesangial areas along with subepithelial humps, but a continuous intramembranous deposition was not obvious. In the sequential biopsy, the deposits were more often seen in the intramembranous area and finally formed a continuous osmiophilic substance, which is a characteristic feature of DDD. In case 2, continuous intramembranous deposition already coexisted with endocapillary proliferation at the first biopsy. In both cases, endocapillary proliferation was alleviated slightly as time progressed. The present report suggests that endocapillary proliferative glomerulonephritis is the earliest lesion in some cases of DDD. Detailed review of a clinical history and a subsequent follow-up biopsy should be done to distinguish these lesions from other types of endocapillary proliferative glomerulonephritis.     

血管内皮生长因子、细胞间黏附分子1在糖尿病大鼠肾小球的表达

目的 探讨血管内皮生长因子(VEGF)和细胞间黏附分子1(1CAM-1)在糖尿病肾病(DN)发生机理中的作用。方法 采用链脲佐菌素(STZ)诱发糖尿病(DM)大鼠模型，观察大鼠肾小球肥大、肾功能和24h尿蛋白改变以及用免疫组织化学和计算机图像分析技术定位、半定量检测VEGF和ICAM—1在DM大鼠肾小球的表达。结果 VEGF和ICAM—1在糖尿病大鼠肾小球中均有不同程度表达，VEGF主要分布于肾小球脏层上皮细胞的脑浆之中，ICAM—1主要分布于肾小球内皮细胞和系膜细胞的脑浆中。VEGF、ICAM-1水平与蛋白尿和肾小球肥大呈正相关关系。结论 DM大鼠肾小球VEGF和ICAM-1的升高可能参与了DN的疾病发展过程，估计是糖尿病肾病发生机理之一。     

犬股静脉同时获取内皮细胞和肌成纤维细胞的方法研究

目的　寻找一种简便、有效的方法 ,从股静脉同时获取内皮细胞和肌成纤维细胞。方法　取犬股静脉 5cm ,将静脉内膜外翻 ,两端内套、夹闭 ,胶原酶消化法获取内皮细胞 ,去内皮的静脉采用组织块贴壁法获取肌成纤维细胞。结果　应用本方法获得的内皮细胞纯度达 99.19% ,79天即可获得 1× 10 6个肌成纤维细胞 ,而细胞的增殖分化能力并未受影响。结论　本方法简便、易行 ,获得的内皮细胞纯度高 ,肌成纤维细胞培养周期缩短。     

大鼠骨髓与外周血来源内皮祖细胞生物学特性比较

背景：内皮祖细胞不仅参与胚胎血管生成,也参与出生后血管发生和血管内膜损伤后修复,对治疗缺血性疾病意义重大,但目前对内皮祖细胞的分离、培养、鉴定还存在争议。 目的：体外分离、培养大鼠骨髓与外周血来源的内皮祖细胞,并比较其生物学特性。 方法：密度梯度离心法分离SD大鼠骨髓和外周血单个核细胞,接种于纤维连接蛋白铺被的培养瓶中贴壁培养,用加入血管内皮生长因子、碱性成纤维细胞生长因子及表皮生长因子的完全培养基诱导培养,对获得的贴壁细胞进行细胞形态学,免疫细胞化学染色,流式细胞仪,透射电镜,以及Dil-acLDL、FITC-UEA-1双荧光染色法检测。 结果与结论：骨髓来源的内皮祖细胞数量多,集落状生长,增殖能力强;外周血来源的内皮祖细胞数量较少,散在生长,消化后能贴壁但不能传代。两种不同来源的内皮祖细胞免疫细胞化学检测贴壁细胞CD133、CD34、Flk-1、Ⅷ因子在不同时段呈阳性表达;激光共聚焦显微镜观察,Dil-acLDL、FITC-UEA-1均为双染。透射电镜检查外周血来源的内皮祖细胞发现W-P小体。提示大鼠骨髓和外周血均能分离培养出内皮祖细胞,但前者是早期内皮祖细胞,后者为晚期内皮祖细胞,两者生物学特性各不相同。     

Circulating endothelial cells in Kawasaki disease

Recent reports have demonstrated that circulating endothelial cells (CECs) are observed in several diseases with vascular injury. Because Kawasaki disease (KD) is one type of systemic vasculitis, we hypothesized that an increased number of CECs may be associated with the appearance of complicated coronary artery lesions (CAL). In the present study we investigated the enumeration and origin of CECs in 20 patients with KD, using an immunohistochemical method with monoclonal antibodies: clone P1H12 against ECs and clone AC133 against endothelial progenitor cells (EPCs), which were derived from the bone marrow. The mean number of CECs increased significantly (P < 0.05) from the acute through the subacute phases of KD compared with both the convalescent phase of KD and healthy children. The mean number of CECs was significantly (P < 0.05) higher in six KD patients with CAL than in 14 KD patients without CAL. The population of EPCs in the total CECs in KD was 4.4 +/- 1.2% (range 0-18%). The number of EPCs during the subacute phase was also significantly higher (P < 0.05) in KD patients with CAL than in those without CAL. Our findings indicate that the number of CECs increase in KD vasculitis and suggest that the increased numbers of CECs and EPCs may reflect the EC damage of this disease.     

肾移植后吗替麦考酚酯联合低剂量他克莫司加皮质激素的应用

背景：足量吗替麦考酚酯联合低剂量他克莫司和皮质激素可能是目前针对肾移植受者的理想治疗方案,该方案因其具有低肾毒性以及较少的不良反应和较强的免疫抑制作用已在临床上开始逐渐普及。 目的：以吗替麦考酚酯联合标准剂量他克莫司加皮质激素为对照,评估吗替麦考酚酯联合低剂量他克莫司加皮质激素在肾移植患者中的疗效和安全性。 方法：210例首次接受单一器官同种异体移植的肾移植成人受者被随机分配到他克莫司标准剂量组(n=104)和他克莫司低剂量组(n=106),并接受12个月的治疗。主要疗效指标包括肾移植后第12个月慢性移植物损伤指数(CADI)以及肾小球滤过率;次要疗效指标主要包括急性排斥反应发生率、治疗失败率以及患者和移植肾的存活率等;同时对新发移植后糖尿病,新发高血压,新发高血脂等安全性指标进行评价。 结果与结论：两组绝大多数患者使用了足量的吗替麦考酚酯(1.5 g/d及以上)。在他克莫司剂量方面,他克莫司标准剂量组大多数受试者的实际血药浓度水平偏低,与低剂量组的实际血药浓度水平类似,由此反映了吗替麦考酚酯联合低剂量他克莫司和皮质激素方案已广泛为目前临床医师接受和使用。因此,两组也表现出类似的疗效和安全性：他克莫司标准剂量组和低剂量组肾移植后12个月肾脏病理改变的平均CADI评分分别为1.82分和2.13分(P=0.081 3),平均肾小球滤过率分别为77.08 mL/min和       80.12 mL/min(P=0.794 9),急性排斥反应发生率分别为2.6%和5.2%(P=0.681 2),患者和移植肾存活率分别高达100%和99.1%(P=1.000 0)。在安全性方面,他克莫司标准剂量组和低剂量组新发移植后糖尿病的比例分别为2.9%和1.9%,新发高血脂的比例分别为2.9%和3.8%。结果显示在吗替麦考酚酯联合他克莫司和皮质激素的肾移植免疫抑制治疗方案中,足量吗替麦考酚酯的使用,可以减少他克莫司的剂量,在保持较强的免疫抑制作用即成功地降低急性排斥反应发生率的同时,显著减少他克莫司所致的肾毒性、高血脂和新发糖尿病等不良反应,较好地达到了疗效和毒性间的平衡。