肾移植受者他克莫司剂量/浓度个体差异影响因素及其变化规律

Factors responsible for inter-individual variations in dosage/concentration of tacrolimus in renal transplant recipients

目的探讨肾移植受者他克莫司剂量/浓度个体差异影响因素及其变化规律。方法观察118例肾移植术后早期(3、7、14、30d)、103例术后3月、75例术后6月、119例稳定期(≥1年)口服他克莫司+霉酚酸酯+泼尼松三联免疫抑制抗排斥的受者,记录性别、年龄、身高、体质量、他克莫司剂量、激素剂量、腹泻、血脂、肝功、肾功、白蛋白、红细胞比容,测定每个受者CYP3A5和MDR13435、2677、1236位点基因多态性及不同时期他克莫司药物浓度。然后以他克莫司浓度/剂量×体表面积为因变量分别进行多元线性回归分析。结果肾移植术后早期多元线性回归模型拟合度偏低,术后3月明显增高,术后6月进一步增高并逐渐趋于稳定;影响他克莫司剂量/浓度的因素在术后早期较多且变化剧烈,术后3月以后逐渐趋于稳定。从药物基因组学角度来看,影响他克莫司剂量/浓度的主要因素是MDR13435、MDR12677、MDR11236且术后早期变化剧烈,CYP3A5作用相对较弱且仅在稳定期入选,稳定期影响他克莫司代谢的主要因素是MDR13435。除药物基因组学因素外,年龄、肝功值、白蛋白和红细胞比容与他克莫司浓度/剂量×体表面积呈正相关,是个体差异的重要原因。结论肾移植术后他克莫司剂量/浓度影响因素的变化规律与肾移植临床特点相吻合,不同时期他克莫司剂量/浓度个体差异的影响因素不同。药物基因组学是影响他克莫司剂量/浓度个体差异的重要因素,临床用药应尽量避免对他克莫司代谢干扰大的药物。年龄、肝功、白蛋白、红细胞比容和激素剂量也是他克莫司剂量/浓度个体差异的重要原因。

Objective To identify the factors responsible for the inter-individual variations in the dosage/concentration of tacrolimus in renal transplant recipients. Methods This study involved renal transplant recipients receiving immunosuppressive therapy with the tacrolimus, mycophenolate and prednisone regimen after the operation. The gender, age, height, body weight, tacrolimus dosage, hormone dosage, diarrhea, blood lipids, liver function, renal function, albumin, and hematocrit of the patients were recorded at different time points, namely in early stage （3, 7, 14, and 30 days postoperatively, 118 cases）, at 3 months （103 cases）, 6 months （75 cases） and over one year （119 cases） after the operation. The concentrations oftacrolimus and gene polymorphisms at CYP3A5, MDR1 3435, MDR1 2677 and MDR1 1236 were also determined in these patients. Multiple linear regression was used for analysis of these factors with tacrolimus concentration/dosage＊body surface area as the independent variable. Results Patients in early stage following renal transplantation showed rather poor fitting of the stepwise regression model, which increased obviously 3 months after the operation and further increased till reaching a stable level at 6 months. Multiple factors were found to affect tacrolimus concentration/dosage in the early postoperative stage, during which period these factors underwent drastic variations and became stable 3 months later. In terms of pharmacogenomics, the major factors affecting tacrolimus concentration/dosage included MDR1 3435, MDR1 2677 and MDR1 1236 polymorphisms, which vastly varied between the patients early after the operation. Of these polymorphic sites, CYP3A5 produced only minor effects on tacrolimus concentration/dosage, and was not included as an active factor until the stable phase （over 1 year） following the transplantation; MDR1 3435 was found to be the predominant factor affecting tacrolimus metabolism in the stable phase. Age, liver function, albumin and hematocrit were found to be positively correlated to the independent variable tacrolimus concentration/dosage＊body surface area, and identified as important factors responsible for the intra-individual variation of tacrolimus dosage/concentration. Conclusion The variations in the factors affecting tacrolimus dosage/concentration after renal transplantation are consistent with the clinical features of the patients, and these factors vary with the postoperative stages. Pharmacogenomic factors produce the most conspicuous effect on tacrolimus dosage/concentration, and agents that may interfere with tacrolimus metabolism should be avoided after the operation. Age, liver function, albumin and hematocrit are also important factors responsible for the variation of tacrolimus dosage/concentration.