雷帕霉素加重蛋白负荷肾病大鼠肾脏的损害及氯沙坦的保护作用

目的 观察雷帕霉素对蛋白负荷肾病大鼠肾脏组织和肾功能的影响及氯沙坦的保护作用，并探讨相关机制。 方法 采用牛血清蛋白（BSA）诱导Wistar雌性大鼠建立蛋白负荷的肾病大鼠模型，根据处理不同分成模型对照组、雷帕霉素组（单纯使用雷帕霉素，Rapa组）和氯沙坦组（同时使用雷帕霉素和氯沙坦）。检测不同时间点各组大鼠的尿蛋白量（24 h）和肾功能水平，并对肾组织进行光镜和电镜检查。 结果 实验第7 天，Rapa组和氯沙坦组大鼠尿蛋白量（24 h）均显著高于模型组（均P < 0.05），但氯沙坦组大鼠尿蛋白量（24 h）较Rapa组有明显缓解（P < 0.05）。实验第14天，Rapa组大鼠尿蛋白量（24 h）仍显著高于模型组（P <0.05），而氯沙坦组与模型对照组间的尿蛋白量（24 h）差异已无统计学意义。肾组织光镜检查显示Rapa组大鼠肾小管管腔中的蛋白管型明显增加；而氯沙坦组的蛋白尿和蛋白管型较Rapa组有明显减少；电镜结果显示Rapa组肾脏可见明显的肾小球局灶性足突融合。 结论 雷帕霉素增加蛋白负荷肾病大鼠的蛋白尿水平，其主要机制可能与雷帕霉素损伤肾小球足细胞后导致肾小球滤过屏障的改变有关；氯沙坦可以减轻雷帕霉素所致的大量蛋白尿。     

柴芩肾安方对IgA肾病大鼠肾小球足细胞nephrin表达的影响

目的：探讨柴芩肾安方对IgA肾病（IgAN）大鼠肾小球足细胞nephrin表达的影响。方法：通过切除单侧肾并反复静脉注射葡萄球菌肠毒素B（SEB）复制大鼠IgAN模型,分为正常组、切肾组、IgAN组、柴芩肾安方组和氯沙坦组。第12周末,检测各组大鼠24h尿蛋白量（Upr）,观察肾小球形态学和超微结构变化,并采用免疫组化和实时定量PCR法检测肾小球足细胞nephrin蛋白及mRNA的表达。结果：与正常组相比,IgAN组大鼠Upr显著升高（P〈0.01）,肾小球系膜增生,足突融合明显,足细胞nephrin蛋白及mRNA表达均明显下调（P〈0.01）。经柴芩肾安方治疗后上述指标均明显改善,与IgAN组比较差异有统计学意义（P〈0.01或P〈0.05）。结论：柴芩肾安方能减轻IgAN大鼠蛋白尿及肾小球病变,这可能与其恢复肾小球足细胞nephrin表达有关。     

益肾胶囊对糖尿病肾病大鼠足细胞损伤的影响

目的：观察益肾胶囊对糖尿病肾病大鼠足细胞损伤的影响。方法：32只大鼠随机分为正常对照组、糖尿病肾病模型组（模型组）、益肾胶囊组、苯那普利组,每组各8只。益肾胶囊组每日每只灌胃益肾胶囊（2.5g·kg^-1·d^-1）,苯那普利组每日每只灌胃苯那普利（2.5g·kg^-1·d^-1）,正常对照组及模型组每日给予等量的蒸镏水。测定血压、24h尿蛋白定量、血肌酐（Scr）、尿素氮（BUN）,并计算内生肌酐清除率（Ccr）;光镜检查肾组织病理变化,电镜及免疫荧光法检测肾组织及尿液中足细胞变化等。结果：实验24周后,模型组大鼠血压、24h尿蛋白定量、BUN、Scr较正常对照组明显增高（均P〈0.05）,益肾胶囊组和苯那普利组可降低糖尿病肾病大鼠血压、24h尿蛋白定量、BUN、Scr（均P〈0.05）等;模型组足细胞podocalyxin蛋白表达明显低于正常对照组（P〈0.05）,益肾胶囊组及苯那普利组大鼠足细胞podocalyxin蛋白表达较模型组显著增加（P〈0.05）;两治疗组之间比较无统计学差异。正常对照组尿液偶见podocalyxin阳性足细胞,模型组尿液足细胞排泄较正常对照组明显增多（P〈0.05）,益肾胶囊组及苯那普利组,大鼠尿液足细胞排泄减少（P〈0.05）。结论：益肾胶囊可通过减轻糖尿病肾病大鼠足细胞损伤而具有一定的肾保护作用。     

益肾胶囊对糖尿病肾病模型肾小球足细胞的影响

目的：观察益肾胶囊对糖尿病肾病（DN）大鼠肾组织病理改变及足细胞超微结构的影响。方法：将60只Wis-tar大鼠随机分为4组：正常对照组（对照组）、DN模型组（模型组）、苯那普利组、益肾胶囊组。于注射链脲佐菌素（STZ）后3d起,苯那普利组每日每只灌胃苯那普利3.125mg.kg-1.d-1,益肾胶囊组每日每只灌胃益肾胶囊625mg.kg-1.d-1,对照组及模型组每日给予等量的蒸镏水。各组分别干预12周,观察24h尿蛋白定量、血肌酐（Scr）、尿素氮（BUN）的变化,同时行肾脏病理检查。结果：12周末,模型组大鼠24h尿蛋白定量、Scr、BUN均高于对照组（P〈0.05）。苯那普利组及益肾胶囊组24h尿蛋白定量、Scr、BUN均低于模型组（P〈0.05）。光镜下模型组大鼠肾小球系膜基质增多,系膜区增宽;电镜下模型组大鼠肾小球基底膜增厚,足细胞排列紊乱,数目减少,足突增宽、融合。苯那普利组及益肾胶囊组肾小球基底膜病变减轻,细胞外基质减少,足细胞数目增多,足突融合减轻。结论：益肾胶囊能降低尿蛋白排泄,改善肾功能,并对足细胞有一定的保护作用,从而延缓大鼠糖尿病大鼠肾脏损害。     

肾炎康复片对糖尿病肾病大鼠肾组织Podocalyxin表达的影响

目的：观察肾炎康复片对糖尿病肾病大鼠肾组织Podocalyxin表达、生化指标及病理改变的影响。方法：40只雌性Wistar大鼠随机分为正常对照组、DN模型组（模型组）、肾炎康复片治疗组（中药组）、氯沙坦钾治疗组（西药组）。复制糖尿病肾病大鼠模型,并予药物干预。分别观察不同时期各组大鼠血糖、24h尿蛋白定量,12周末大鼠肾组织Podocalyxin表达水平、Scr、BuN及肾脏组织病理变化。结果：12周模型组、中药组、西药组大鼠Podocalyxin蛋白表达均显著低于同期正常对照组（P〈0．05）,肾组织病理损伤明显,24h尿蛋白定量较正常对照组显著增高（P〈0．05）。12周末用药组大鼠肾组织Podocalyxin蛋白表达显著高于同期模型组（P〈0．05）,肾组织病理损伤较模型组明显减轻。血糖水平略低于同期模型组,但差异无统计学意义（P〉0．05）,24h尿蛋白定量、BUN、Scr水平显著低于同期模型组（P〈0．05）。结论：肾炎康复片能够上调糖尿病肾病大鼠肾组织Podocalyxin表达水平,对糖尿病肾病肾脏损伤有保护性作用。     

温阳活血利水方对阿霉素肾病大鼠肾小球足细胞podocin表达的影响

目的：观察温阳活血利水法治疗微小病变肾病综合征的疗效并探讨其作用机制。方法：SPF级雄性Wistar大鼠50只,随机分为正常组、模型组、泼尼松组、中药组。正常组尾静脉一次性注射生理盐水1ml,其余各组均采用阿霉素5.5mg/kg一次性尾静脉注射。1周后开始药物干预,持续4周。观察实验大鼠的一般情况;检测大鼠24h尿蛋白定量;检测总蛋白、白蛋白、总胆固醇、三酰甘油、低密度脂蛋白的水平;采用RT-PCR和免疫荧光染色测定大鼠肾小球podocin的mRNA和蛋白表达水平;光学显微镜观察肾组织形态学变化;电镜下观察足细胞足突的变化。结果：模型组24h尿蛋白定量明显升高（P〈0.01）,血清总蛋白、白蛋白明显降低（P〈0.01）,血清脂质水平升高（P〈0.01）,podocin mRNA与蛋白表达明显减少,足突融合明显。两个治疗组均能降低24h尿蛋白定量,升高血清总蛋白、白蛋白水平（P〈0.01）。温阳活血利水方能降低血清脂质水平（P〈0.01）。两个治疗组均能改善肾组织中podocin mRNA与蛋白的表达的减少,改善其肾组织的病理改变。结论：温阳活血利水方能改善阿霉素肾病大鼠肾小球podocin的表达减少,减轻肾组织的病理改变,这可能是温阳活血利水方减少蛋白尿的重要作用机制。     

黄芪对阿霉素肾病大鼠的足细胞影响实验研究

目的：动态观察阿霉素肾病大鼠的蛋白尿、血清白蛋白及足细胞足突的变化;观察单味中药黄芪、泼尼松及两者联合应用对阿霉素肾病大鼠的蛋白尿、血清白蛋白及足细胞足突的影响。方法：单次尾静脉注射阿霉素建立阿霉素肾病大鼠模型,在14d、28d、56d时检测每组大鼠的24h尿蛋白、血清白蛋白、血脂的水平;同时各组处死2只大鼠留取肾脏标本,应用透射电镜观察各组大鼠各时间点的足细胞足突的变化。结果：（1）各肾病大鼠从14d开始24h尿蛋白显著高于对照组（P〈0．01）,24h尿蛋白持续增高,但到56d时尿蛋白有所下降,与此同时,血清白蛋白降低。（2）透射电镜显示14d时肾病组足突不同程度变宽,28d时足突弥漫性融合,56d时足突融合有所减轻。（3）与肾病组相比,到56d时黄芪组尿蛋白较对照组减少且足突融合较肾病组改善明显,血清白蛋白较肾病组升高（P〈0．05）。（4）到56d时,与其他各肾病组相比,泼尼松加黄芪组尿蛋白最少（P〈0．01）,电镜显示足突病变改善最明显。结论：中药黄芪能减少阿霉素肾病大鼠的尿蛋白、改善蛋白质代谢及减轻足细胞损害;黄芪与泼尼松合用能更好地减轻尿蛋白,升高血清白蛋白,减轻足细胞和足突的病变。     

实脾固肾化瘀方对阿霉素肾病大鼠足细胞影响的实验研究

目的：观察实脾固肾化瘀方对阿霉素肾病大鼠蛋白尿及足细胞的影响。方法：将雄性SD大鼠随机分为4组（正常组,模型组,化瘀方组,蒙诺组）,除正常组外,其余大鼠采用静脉注射阿霉素（4mg/kg）法制成阿霉素肾病大鼠模型。造模后2周化瘀方组予实脾固肾化瘀方浸膏（43g/kg）;蒙诺组予福辛普利溶液（2mg/Kg）;正常和模型组予生理盐水每日1次灌胃。观察45d后留取大鼠24h尿蛋白定量,取血处死并取肾脏组织观察实脾固肾化瘀方组对阿霉素肾病大鼠足细胞的影响。结果：化瘀方组大鼠24h尿蛋白定量较模型组明显降低（P〈0.05）,与蒙诺组差异无统计学意义（P〉0.05）。光镜观察化瘀方组大鼠肾小球系膜细胞及基底膜增生程度均较模型组明显改善。化瘀组透射电镜观察化瘀方组大鼠肾小球足细胞足突融合、基底膜增厚等病理变化均较模型组明显改善。结论：实脾固肾化瘀方对阿霉素肾病大鼠足细胞有保护作用。     

糖尿病大鼠肾脏α-辅肌动蛋白-4表达变化及作用机制

目的：动态观察肾小球足细胞骨架蛋白α-辅肌动蛋白-4（α-actinin-4）在糖尿病大鼠模型肾组织中表达的变化,探讨α-actinin-4与蛋白尿发生的关系及导致其出现变化的可能机制。方法：将SD大鼠随机分为两组：对照组及糖尿病组,腹腔注射链脲佐菌素（STZ）制作糖尿病大鼠模型,分别于2、4、6、8周末检测每组大鼠24h尿蛋白定量并处死大鼠留取肾标本。电镜观察足细胞超微结构的变化;应用酶免法检测肾组织糖基化终产物（AGEs）的含量;应用免疫组化及Western-blot检测α-actinin-4蛋白的表达;RT-PCR检测α-actinin-4mRNA表达量的变化。结果：6周糖尿病组大鼠24h尿蛋白明显高于对照组（P〈0.01）,增高持续到8周（P〈0.01）;透射电镜显示8周糖尿病组大鼠足突出现节段性融合;从4周时糖尿病组大鼠肾组织AGEs含量明显升高（P〈0.05）,并持续到8周（P〈0.01）;与对照组相比,从4周时糖尿病组大鼠肾组织α-actinin-4蛋白表达明显降低（P〈0.05）,并持续到8周（P〈0.05）;与对照组相比,从2周时糖尿病组大鼠肾组织α-actinin-4mRNA表达明显降低（P〈0.05）,并持续到8周（P〈0.01）。结论：α-actinin-4表达降低参与了糖尿病大鼠蛋白尿的发生,而AGEs可能是导致α-actinin-4表达下调的原因之一。     

霉酚酸酯及缬沙坦对糖尿病大鼠足细胞的保护机制研究

目的探讨霉酚酸酯、缬沙坦及2者联合应用对糖尿病。肾病（DN）大鼠足细胞损伤的保护作用。方法雄性Wistar大鼠行右肾切除后，腹腔注射链脲佐菌素（STZ，65mg／kg）建立糖尿病模型。将实验动物随机分为右。肾切除对照组（NC）、糖尿病组（DM）、霉酚酸酯治疗组（M）、缬沙坦治疗组（V）、缬沙坦和霉酚酸酯联合治疗组（V＋M）。治疗组分别给予霉酚酸酯15mg·kg^-1·d^-1，缬沙坦40mg·kg^-1·d^-1；联合治疗组为上述两组之和。检测各组8周末的左肾质量／体质量比值、尿蛋白量（24h）、血糖（Glu）、Scr。光镜及电镜观察肾组织形态学变化。免疫组化检测肾组织中nephrin、结蛋白（desmin）及单核细胞趋化因子1（MCP-1）蛋白表达。实时PCR测定肾组织中nephrin及MCP-1mRNA表达。结果与NC组相比，DM组大鼠血糖、尿蛋白量及左肾质量／体质量比值均显著上升（P〈0．01）；肾小球硬化指数（GSI）及肾间质损害加重（P〈0．01）；肾组织内MCP-1、desmin蛋白表达均显著上调（P〈0．01）。与DM组比较，M组、V组及V＋M组上述指标除Glu、Scr外，均明显改善（P〈0．05或P〈0．01）。与NC组（100％）相比，DM组nephrinmRNA表达下调（78％，P〈0.05）；各治疗组nephrinmRNA表达增加，以M组增加最明显（134％，P〈0．01）。与NC组（100％）相比，DM组MCP-1mRNA表达明显上调（251％，P〈0.05）；各治疗组明显降低，以M组最显著（126％，P〈0．01）。nephrinmRNA与MCP-1mRNA表达呈负相关（r=-0，86。P〈0．01）。尿蛋白量（24h）与MCP-1mRNA呈正相关fr=0．82，P〈0．01）；与nephrinmRNA呈负相关（r=-0．78，P〈0．01）。结论霉酚酸酯及缬沙坦均能下调糖尿病大鼠肾组织中desmin及MCP-1基因及蛋白的表达，上调nephrin基因及蛋白表达，降低尿蛋白量，预防肾损伤。联合治疗不优于单一治疗。霉酚酸酯可能通过抗炎性反应减轻足细胞损伤，减少蛋白尿，对早期DN大鼠具有明显的肾保护作用。     

Rapamycin worsens renal function and intratubular cast formation in protein overload nephropathy

BACKGROUND: Rapamycin (sirolimus) is associated with functional nephrotoxicity in some patients with nephrotic glomerular diseases but the pathophysiologic mechanisms are not known. This study investigated the effects of rapamycin on renal function and structure in protein overload nephropathy. METHODS: Rats with protein overload nephropathy [induced by bovine serum albumin (BSA), 2.1 g by daily intraperitoneal injection, day 0 to day 3] received daily intraperitoneal injections of either vehicle [dimethyl sulfoxide (DMSO)], rapamycin (0.2 mg/kg, an inhibitor of mammalian target of rapamycin), or roscovitine (3.5 mg/kg, a small molecule cyclin-dependent kinase inhibitor) (N= 9 each) from day -3 to day 3. RESULTS: In protein overload nephropathy, rapamycin caused severe acute renal failure and mild hypercholesterolemia (both P < 0.05). Rapamycin dramatically increased intratubular cast formation, and proximal tubular epithelial cells were swollen and engorged with increased cytoplasmic protein droplets. The number of 5-bromo-2'-deoxyuridine (BrdU)-positive tubular epithelial cells increased by more than 20-fold on day 3 in protein overload nephropathy, and this was attenuated by 65% with rapamycin (P < 0.05), whereas roscovitine was ineffective. Rapamycin increased the protein expression of p27(kip1) in tubular epithelial cells, but did not alter D-type cyclin expression or apoptosis. CONCLUSION: Rapamycin caused a specific pattern of acute renal injury characterized by increased intratubular cast formation in protein overload nephropathy. This could be due to disruption of a potentially important compensatory mechanism in nephrotic glomerular diseases involving tubular epithelial cell protein endocytosis and proliferation.     

BK Polyomavirus Replication in Renal Tubular Epithelial Cells Is Inhibited by Sirolimus,but Activated by Tacrolimus Through a Pathway Involving FKBP‐12

BK polyomavirus (BKPyV) replication causes nephropathy and premature kidney transplant failure. Insufficient BKPyV‐specific T cell control is regarded as a key mechanism, but direct effects of immunosuppressive drugs on BKPyV replication might play an additional role. We compared the effects of mammalian target of rapamycin (mTOR)‐ and calcineurin‐inhibitors on BKPyV replication in primary human renal tubular epithelial cells. Sirolimus impaired BKPyV replication with a 90% inhibitory concentration of 4 ng/mL by interfering with mTOR–SP6‐kinase activation. Sirolimus inhibition was rapid and effective up to 24 h postinfection during viral early gene expression, but not thereafter, during viral late gene expression. The mTORC‐1 kinase inhibitor torin‐1 showed a similar inhibition profile, supporting the notion that early steps of BKPyV replication depend on mTOR activity. Cyclosporine A also inhibited BKPyV replication, while tacrolimus activated BKPyV replication and reversed sirolimus inhibition. FK binding protein 12kda (FKBP‐12) siRNA knockdown abrogated sirolimus inhibition and increased BKPyV replication similar to adding tacrolimus. Thus, sirolimus and tacrolimus exert opposite effects on BKPyV replication in renal tubular epithelial cells by a mechanism involving FKBP‐12 as common target. Immunosuppressive drugs may therefore contribute directly to the risk of BKPyV replication and nephropathy besides suppressing T cell functions. The data provide rationales for clinical trials aiming at reducing the risk of BKPyV replication and disease in kidney transplantation.     

Is sirolimus a safe alternative to reduce or eliminate calcineurin inhibitors in chronic allograft nephropathy in kidney transplantation?

PURPOSE: We evaluate whether cyclosporine (CsA) or tacrolimus (FK) could be reduced or eliminated after sirolimus was added in chronic allograft nephropathy (CAN). By reducing doses of CsA or FK, we expected that renal function would improve. METHOD AND MATERIAL: Twenty-one patients with CAN had sirolimus added as an immunosuppressive agent. We evaluated the creatinine (Cr) level 3 months after addition. The doses of CsA and FK were decreased gradually and then eliminated over a course of 4 to 6 weeks. If the Cr level rose rapidly or other prominent signs of rejection occurred; low-dose CsA or FK would be added per protocol. We evaluated the duration of engraftment before sirolimus and the Cr level when it was added. RESULTS: Renal function improved in 13 of 21 cases. The improvement in Cr ranged from 12.5% maximally to 1.84% minimally. Seven of 13 cases still required low-dose CsA. The average duration of engraftment before sirolimus was 13.66 +/- 10.80 months. The average Cr level before sirolimus was 1.65 +/- 0.56 mg/dL. In the other eight cases, the Cr level kept rising from 5.1% to 20.4%. The average duration of engraftment was 88.38 +/- 42.21 months. The average Cr level before sirolimus was 2.85 +/- 0.54 mg/dL. Hyperuricemia was noted in 31.3% and hyperlipidemia in 68.8%. CONCLUSION: Sirolimus is a safe alternative to reduce or eliminate CsA or FK in CAN. In cases with a long duration of engraftment and high Cr level, sirolimus might have some effect as a substitute for CNI and thus prevent further nephrotoxicity.     

肾移植后使用西罗莫司继发间质性肺炎七例

目的 分析肾移植术后使用西罗莫司(SRL)的受者继发间质性肺炎的情况,以指导临床治疗。方法 7例肾移植受者在使用SRL后发生间质性肺炎8次,其中2例初始免疫抑制治疗即采用含SRL的方案,5例的初始免疫抑制方案为他克莫司（或环孢素A）+吗替麦考酚酯+泼尼松,后因移植肾肾病（4例）或并发肿瘤（1例）而将他克莫司（或环孢素A）转换为SRL。发生间质性肺炎时,临床表现为发热,伴有呼吸道症状以及呼吸困难,CT和胸片检查有阳性表现。结果 发生间质性肺炎后,4例5次停用SRL,另外3例减少SRL的用量,3～14 d后发热和呼吸道症状逐渐好转,2～4周后胸部影像学检查提示肺炎开始逐渐吸收,而病变完全吸收则需要2～6个月。结论 肾移植后使用SRL可继发间质性肺炎,一旦发生间质性肺炎,应立即减少SRL的用量或停用SRL。     

Sirolimus-associated eyelid edema in kidney transplant recipients

BACKGROUND: The immunosuppressant sirolimus is effective in preventing acute rejection episodes. So far, unusual edema formation has not been reported as a side effect. METHODS: Two groups of patients with renal transplants, consisting of 11 patients each, were followed for up to 29 months. The immunosuppressive regimen was either sirolimus and prednisone with or without cyclosporine or azathioprine/mycophenolate and prednisone with cyclosporine. Routine follow-up included a thorough clinical investigation. Edema formation was documented photographically. RESULTS: In 5 of the 11 patients treated with sirolimus uni- or bilateral, non-itching, eyelid edema was observed. After discontinuation of sirolimus, lid edema disappeared. The duration until recovery varied from weeks to months. No cause of edema formation other than the treatment with sirolimus was detected. CONCLUSIONS: Severe eyelid edema formation seems to be associated with sirolimus treatment. The underlying mechanism is unknown.     

mToR inhibitors-induced proteinuria: mechanisms, significance, and management

Massive urinary protein excretion has been observed after conversion from calcineurin inhibitors to mammalian target of rapamycin (mToR) inhibitors, especially sirolimus, in renal transplant recipients with chronic allograft nephropathy. Because proteinuria is a major predictive factor of poor transplantation outcome, many studies focused on this adverse event during the past years. Whether proteinuria was due to sirolimus or only a consequence of calcineurin inhibitors withdrawal remained unsolved until high range proteinuria has been observed during sirolimus therapy in islet transplantation and in patients who received sirolimus de novo. Podocyte injury and focal segmental glomerulosclerosis have been related to mToR inhibition in some patients, but the pathways underlying these lesions remain hypothetic. We discuss herein the possible mechanisms and the significance of mToR blockade-induced proteinuria.     

Renal reserve test: its methodology and significance

Renal reserve (RR) is the ability of the kidneys to increase their basal glomerular filtration rate (GFR) by at least 20% after a protein overload. It has been documented that RR is preserved in healthy elderly people, and even in patients with chronic kidney disease, but its magnitude is significantly decreased with aging. Besides, RR has also been evaluated in kidney transplant patients who were on sirolimus or calcineurin inhibitors (CNI):cyclosporine or tacrolimus, and it was found that RR was lower in the CNI group compared to the sirolimus group, a phenomenon that could be attributed to the intra- renal vasoconstrictive effect of CNI. In conclusion, RR is a physiological variable which has its particular characteristics in different renal settings.     

Impact on renal function of the use of sirolimus in cardiac transplantation

INTRODUCTION: During the last few years sirolimus has been introduced as an alternative to preserve renal function in transplant recipients receiving calcineurin inhibitors. MATERIALS AND METHODS: We reviewed our results on the use of sirolimus in cardiac transplant recipients. RESULTS: Twenty-seven patients with an average age of 63 years received sirolimus. The average time after transplantation was 73.4 +/- 58.9 months and the average follow-up was 31.7 +/- 18.01 months. Sirolimus was prescribed in 37% of cases due to chronic renal failure (CRF), 14.8% because of cardiac allograft vasculopathy (CAV), 11.1% for tumors, 22.2% de novo, 7.4% for CRF and tumor, and 7.4% for CRF and CAV. Among the patients with CRF (n = 14), there were 5 (35%) on dialysis at the moment of starting the treatment and 1 was retired from dialysis. The other 4 (28.5%) patients had to be treated with dialysis after starting the treatment. In all, 42.8% of the patients with nephropathy maintained stable renal function or improved. Among the 17 (63%) patients who did not require dialysis, there was no significant change in renal function after 6 months or 1, 2, and 3 years follow-up. CONCLUSIONS: The use of sirolimus in cardiac transplantation maintains stable renal function in the majority of patients in the medium term.     

Conversion to Sirolimus for Chronic Allograft Nephropathy and Calcineurin Inhibitor Toxicity and the Adverse Effects of Sirolimus After Conversion

Background

Chronic allograft nephropathy and calcineurin inhibitor toxicity may cause graft loss. After kidney transplantation, especially among those patients with chronic allograft nephropathy, sirolimus may be a good alternative to calcineurin inhibitors. Unlike calcineurin inhibitors, sirolimus is devoid of significant nephrotoxicity, but approximately 30% to 50% of patients on sirolimus therapy display mild or severe adverse effects. We sought to report our experience with sirolimus conversion among patients with chronic allograft nephropathy as well as the mild versus severe adverse effects that limit the drug's use.

Materials and Methods

We analyzed the outcomes of 88 patients (64 men and 24 women) of overall mean age of 35.9 ± 9.9 years (range, 21-59 years) who had undergone kidney transplantation. Immunosuppressive therapy had been converted from a calcineurin inhibitor to sirolimus because of biopsy-proven chronic allograft nephropathy, calcineurin inhibitor toxicity, or presence of malignancy. We excluded patients with prior acute rejection episodes. Subjects were divided into two groups with respect to their creatinine levels: Group A < 2 mg/dL and Group B ≥ 2 mg/dL. After conversion to sirolimus, possible adverse effects of sirolimus were evaluated at the follow-up inset. Each patient underwent a physical examination, and estimation of serum lipid and electrolyte levels as well as hemoglobin concentration.

Results

At the time of conversion of the 88 renal transplant patients, their mean duration after grafting was 48 ± 15 months (range, 4-296). The prior treatment consisted of a calcineurin inhibitor, prednisolone, and mycophenolate mofetil. After conversion, the calcineurin inhibitor was stopped and sirolimus was begun. The 48 Group 2 patients (34 men, 14 women) of overall mean posttransplant time of 22.7 ± 14.6 months who underwent conversion displayed a mean serum creatinine increase to 3.2 ± 1.4 mg/dL, including 17 subjects who underwent rejection. The 40 Group 1 patients (30 men, 10 women) with a mean overall posttransplant period of 67.6 ± 49.9 months showed an fall in serum creatinine level to 1.4 ± 0.5 mg/dL among only 3 patients.While 5/88 patients showed no increase in proteinuria (5.6%); 83 (94.4%) did experience it. Proteinuria increased from a mean of 192 ± 316 to 449 ± 422 mg/d. Only three patients displayed heavy proteinuria (>3 g/d); sirolimus was discontinued for this reason. Proteinuria was well controlled in the other patients with angiotensin-converting enzyme and/or angiotensin II receptor inhibitor agents. After sirolimus conversion, serum cholesterol levels increased from 187 ± 42 to 214 ± 52 mg/dL, and serum triglyceride levels increased from 161 ± 61 to 194 ± 102 mg/dL. All but four patients responded to statin therapy, with serum lipid levels falling to acceptable levels. Another four patients developed unilateral lower extremity edema with sirolimus discontinued for this reason. One patient displayed generalized arthralgia.

Conclusion

Chronic allograft nephropathy or calcineurin inhibitor toxicity can lead to loss of graft kidney function. Calcineurin inhibitor toxicity can lead to chronic allograft nephropathy. Patients with a low baseline serum creatinine level who undergo sirolimus conversion showed stabilized kidney function. Late conversion of patients with a serum creatinine above 2 mg/dL face a risk of graft failure. Sirolimus displayed a limited incidence of serious adverse effects; mild or moderate adverse effects, such as hyperlipidemia and proteinuria, were easily controlled with countermeasure therapy.