Relationships between thiopurine S-methyltransferase polymorphism and azathioprine-related adverse drug reactions in Chinese renal transplant recipients

Objective  To systematically investigate the relationships between thiopurine S-methyltransferase (TPMT) polymorphisms and azathioprine-related adverse drug reactions in patients with kidney transplantation. Methods  Erythrocyte TPMT activity of 150 patients with kidney transplantation and AZA therapy was determined by HPLC. The frequency of four common TPMT mutant alleles, TPMT*2, *3A, *3B, and *3C was determined by allele-specific PCR and PCR-restriction fragment length polymorphism (PCR-RFLP) analysis. Results  Thirty cases (20%) had stopped azathioprine medication or were on reduced dose due to azathioprine-related side effects. The TPMT activity range of cases who never experienced side effects was 16.63-68.25 U, the mean of the controls was 38.43 ± 11.59 U. The mean value of 12 cases with hematotoxicity was 23.50 ± 10.33 U, much lower than the control mean (P < 0.05). No significant difference between the mean value of 18 cases with hepatotoxicity and the control mean (P > 0.05) was seen. No case with TPMT deficiency was found in all patients studied, and TPMT*2, *3A, and *3B were not detected in any of them. TPMT*3C heterozygous alleles were found in 4.7% (seven cases) of these patients, all seven cases had intermediate TPMT activity, and the mean was 16.75 ± 2.09 U, much lower than other TPMT wild-type patients (P < 0.05). In the seven TPMT*3C patients, four cases experienced side effects (hematotoxicity, n = 2; hepatotoxicity, n = 2). Conclusions  This study demonstrates that TPMT activity is reduced in patients with TPMT*3C mutation. AZA-induced hematotoxicity is related to the reduced TPMT activity.     

lntracellular thiopurine nucleotides and azathioprine myelotoxicity in organ transplant patients

Aim Despite widespread use of azathioprine in organ transplant recipients, the mechanism of its myelotoxicity remains unclear. The aim of this study was to assess the importance of thiopunne metabolites on bone marrow toxicity.
Methods We investigated the relationship between intracellular concentrations of 6-thioguanine (bTGN), 6-mercaptopunne (6-MPN) and 6-thioxanthine (6 TXN) nucleotides and the absolute count of white or red cells in forty-seven lung or heart/lung transplant patients after oral administration of azathioprine.
Results No significant correlation between red cell concentrations of 6-TGN or total thiopurine metabolites and white or red cell counts was found, with no difference between the sexes. Likewise, high 6-TGN levels were not related to bone marrow depletion.
Conclusions These results suggest that red blood cell 6-TGN alone do not predict the haematopoietic toxicity of azathioprine.     

Phenotypic and genotypic analysis of thiopurine s-methyltransferase polymorphism in the bulgarian population

Genetic polymorphism of TPMT activity is an important factor responsible for large individual differences in thiopurine toxicity and therapeutic efficacy. The aim of this study was to determine the distribution of TPMT activity as well as the types and frequencies of mutant alleles in a Bulgarian population sample. TPMT activity was measured in 313 Bulgarians, using an established HPLC procedure. All individuals with TPMT activity less than 12.0 nmol/(mL Ery.h) (n = 76) were additionally genotyped using a color multiplex hybridization assay. The samples were tested for TPMT*2, *3A, *3B, *3C, *3D, *4, and *6 mutant alleles. TPMT activities varied from 1.1 to 24.0 nmol/(mL Ery.h) [mean 14.2 +/- 3.2 nmol/(mL Ery.h)]: 92.3% of the individuals investigated had high TPMT activity [>10 nmol/(mL Ery. h)], whereas 7.4% were intermediate [2.8-10 nmol/(mL Ery.h)], and 0.3% were low metabolizers [< 2.8 nmol/(mL Ery.h)]. A significant gender-related difference in TPMT activity (P = 0.02) was observed with 6.2% higher values in men than in women. There was no significant correlation between age and enzyme activity (r = 0.06, P = 0.27). Genotype analysis revealed three mutant TPMT alleles: 2, 3A, and 3C. The frequency of these alleles among the TPMT-deficient individuals was 2.17%, 30.4%, and 2.17%, respectively. These data show a similar distribution of TPMT activity among the Bulgarian population investigated as in most other white populations with the frequency of intermediate metabolizers being somewhat lower (7.4% versus approximately 11%) in the Bulgarians. The most common variant allele was TPMT-3A, as in other white populations.     

肾移植受者CYP3A5基因多态性对他可莫司代谢的影响

目的研究CYP3A基因多态性对肾移植受者他可莫司代谢的影响。方法50例肾移植受者采用FK506＋霉酚酸酯＋强的松三联免疫抑制方案,FK506起始剂量0．15mg／（kg·d）,1w后根据目标血药浓度调整。CYP3A5基因多态性检测采用聚合酶链反应-限制性片段长度多态性（PCR—RFLP）方法,50例肾移植受者分为＊1／＊1型（12例）、＊1／＊3型（16例）、＊3／＊3型（22例）共3组。比较6个月内FK506的血药浓度／剂量比。结果 肾移植术后7天、1月、3月、6月＊3／＊3型患者FK506的血药浓度／剂量比显著高于＊1／＊1型和＊1／＊3型（P〈0．05）。结论由于CYP3A5基因多态性影响,＊1／＊1型组的患者早期难以达到有效FK506目标血药浓度,应该提高该组患者的起始用药剂量,根据CYP3A5基因多态性作为FK506个体化用药的依据,可以减少早期急性排斥反应,提高肾移植的临床效果。     

肾移植病人中CYP3A4基因多态性对环孢素A代谢的影响

目的 用基因分析技术对CsA代谢酶CYP3A4进行基因分型,以阐述CYP3A4基因多态性对环孢素A代谢的影响及相互关系,从而预测血药浓度及安全性。方法 用聚合酶链反应结合限制性片段长度多态性分析法分别建立了CYP3A的CYP3A4基因亚型3个新突变点(CYP3A4~*4,~*5,~*6)的基因分型方法,并对中国肾移植人群进行基因分型,同时测定CsA及其代谢物浓度,以原形药与代谢物浓度的比值MR作为表型验证指标。结果CYP3A4~*4,*~5,*~6等位基因在中国肾移植人群中的突变率为:2/133,3/197,3/200。野生型病人中肝肾功能正常和异常者测得MR均值分别为0.47±0.13和0.82±0.21。3种突变型病人MR均值为0.90±0.30。结论CYP3A4~*4,~*5,~*6等位基因的存在有可能降低了药物代谢酶CYP3A4的活性,从而使环孢素A的代谢减慢。     

CYP 3A5*3基因多态性对肾移植术后他克莫司药代动力学的影响

目的探讨CYP3A5*3基因多态性对肾移植术后他克莫司(免疫抑制药)剂量校正给药2h后浓度的影响。方法选取61例肾移植术后患者,用聚合酶链式反应-限制性片段长度多态性的方法,分析CYP 3A5*3基因型;用微粒酶联免疫吸附法,测定患者他克莫司浓度。并分析CYP 3A5*3基因多态性与他克莫司给药剂量、给药2h浓度(C2)及剂量校正给药2h后浓度(C2/D)的相关性。结果肾移植术后1周及1、3个月,CYP 3A5*1/*1 CYP 3A5*1/*3组和CYP3A5*3/*3组他克莫司剂量比较均无显著性差异。术后1周和1个月,2组间他克莫司C2比较无显著性差异;术后3个月,CYP 3A5*1/*1 CYP 3A5*1/*3组的C2显著低于CYP 3A5*3/*3组(P<0.05)。术后1周及1、3个月,CYP 3A5*1/*1 CYP 3A5*1/*3组的C2/D均明显低于CYP 3A5*3/*3组(P<0.05)。结论肾移植术后,他克莫司C2/D的个体化差异与患者CYP3A5*3基因型密切相关。     

Calcineurin inhibitors in pediatric renal transplant recipients

The calcineurin inhibitors, cyclosporine (ciclosporin) [microemulsion] and tacrolimus, are the principal immunosuppressants prescribed for adult and pediatric renal transplantation. For pediatric patients, both drugs should be dosed per body surface area, and pharmacokinetic monitoring is mandatory. While monitoring of the trough levels may suffice for tacrolimus, cyclosporine therapy that utilizes the microemulsion formulation requires additional monitoring (e.g. determination of 2-hour post-dose levels).In a well designed randomized study in children, as in studies in adults, there was no difference in short-term patient and graft survival with cyclosporine microemulsion and tacrolimus. However, tacrolimus was significantly more effective than cyclosporine microemulsion in preventing acute rejection after renal transplantation when used in conjunction with azathioprine and corticosteroids. With regard to long-term outcome, the difference in acute rejection episodes resulted in a better glomerular filtration rate at 1 year after transplantation and eventually in better graft survival 4 years after renal transplantation. Whether this difference persists when calcineurin inhibitors are used in combination with mycophenolate mofetil has not been determined. The prevalence of hypomagnesemia was higher in the tacrolimus group whereas hypertrichosis and gingival hyperplasia occurred more frequently in the cyclosporine group. In contrast with adults, the incidence of post-transplantation diabetes mellitus was not significantly different between tacrolimus- and cyclosporine-treated patients. There was also no difference with regard to post-transplantation lymphoproliferative disorder. Medication costs were similar, but in view of the lower rejection episodes and better long-term graft survival as well as the more favorable cosmetic side effect profile, tacrolimus may be preferable. The recommendation drawn from the available data is that both cyclosporine and tacrolimus can be used safely and effectively in children. We recommend that cyclosporine should be chosen when patients experience tacrolimus-related adverse events.     

Treating erectile dysfunction in renal transplant recipients

Erectile dysfunction is common in male kidney transplant recipients. Interference with the physiology of erections can be attributed to recipient co-morbidities, the renal transplant operation, medication adverse effects, relationship problems and changes in mental health. A treatment-oriented evaluation of erectile dysfunction allows the development of treatment plans that are patient-specific. Hypo-gonadal men whose hormone parameters do not improve after renal transplantation may respond to testosterone replacement therapy. Use of recommended doses of the phosphodiesterase-5 inhibitor sildenafil does not significantly modify trough concentrations of the calcineurin inhibitors ciclosporin and tacrolimus or result in impaired renal allograft function. Tacrolimus has been shown to increase the peak concentration and prolong the elimination half-life of sildenafil in kidney transplant recipients. Daily administration of sildenafil has resulted in decreased blood pressure in kidney transplant recipients with treated hypertension and tacrolimus immunosuppression. Intracavernosal injections of alprostadil, with or without papaverine and phentolamine, are effective treatments for erectile dysfunction after renal transplantation and have not resulted in alterations of ciclosporin concentrations or in deterioration of renal function. Penile prostheses can be successfully implanted after pelvic organ transplantation without significant risk of infection.     

Tolerability of mycophenolate sodium in renal transplant recipients

Background Kidney transplant recipients (KTR) receive fixed daily doses of mycophenolate sodium as part of the immunosuppressive regimen. Dose reductions occur primarily due to adverse events and may be associated with an increased risk of acute rejection and graft loss. Objectives To evaluate the tolerability of mycophenolate in kidney transplant recipients receiving tacrolimus and prednisone. Setting The study was performed at Hospital do Rim, Federal University of São Paulo in Brazil. Method This was a retrospective cohort study including 506 patients. Tolerability of mycophenolate sodium was classified into the following groups: Temporary reduction (TR), definitive reduction (DR), temporary interruption (TI), permanent discontinuation (PD) and without modification (WM). Main outcome measure The cause of mycophenolate dose change and its influence on rejection-free survival during the first 3 years after transplantation. Results The cumulative incidence of dose change was 51.2% (11%TR, 44%DR, 24%TI, and 21%PD). Gastrointestinal (45.3%), infection (31.9%) and hematological (14.9%) systems accounted for most of the dose changes. The adverse events with higher incidence were diarrhea, cytomegalovirus (CMV) infection and leukopenia. Changes in dose of mycophenole were associated with reduced acute rejection-free survival compared with patients WM group (71.4%TR, 58.9%DR, 56.7%TI, 53.7%PD vs. 74.2%WM, p?=?0.020). Only patients with PD showed inferior patient (59.3% vs. 94.4%, p?=?0.001) and death-censored graft (83.3% vs. 92.5%, p?=?0.074) survivals compared to patients WM. Conclusion In this cohort, changes in the dose of mycophenolate were associated with increased risk of acute rejection and permanent discontinuation was associated with inferior patient and graft survival.     

CYP3A5基因型对中国肾移植术后患者体内他克莫司缓释剂型药动学参数的影响

目的研究CYP3A5基因型对中国肾移植术后患者体内他克莫司缓释剂型药动学参数的影响。方法采用化学发光免疫法检测20例肾移植术后患者在服用缓释(10例)和普通剂型(10例)他克莫司后的全血浓度;采用聚合酶链反应-限制性片段长度多态法检测服用缓释剂型他克莫司患者的CYP3A5基因型;缓释剂型组检测0~24 h的11个时间点的血药浓度,而普通剂型检测0~12 h内的10个时间点的血药浓度。结果无剂量校正的缓释剂型组的AUC_(0~24 h)为普通剂型组AUC_(0~12 h)的1.78倍,有剂量校正的缓释剂型组的C_0为普通剂型的60%,其余药动学参数差异无显著性;缓释剂型中慢代谢型组的C_(max)、AUC_(0~24 h)和C_0分别为快代谢型组的1.75、1.96、2.49倍(无剂量校正)以及1.80、2.34和2.64倍(有剂量校正);缓释剂型组的C_0与AUC_(0~24 h)的相关性良好。结论他克莫司普通剂型转换至缓释剂型时应该注意上调给药剂量,同时缓释剂型应结合CYP3A5的基因型检测,确保C_0值在治疗窗范围内。     

Cutaneous effects of sirolimus in renal transplant recipients

Cancer is a major cause of death in immunosuppressed transplant patients. Therefore, sirolimus is frequently used in these patients for its immunosuppressive and antineoplastic properties. However, a variety of cutaneous side effects have resulted from sirolimus therapy. Consequently, dermatologists must be aware of such adverse events and understand the risks and benefits of discontinuing therapy.     

肾移植术后高血压的药物治疗

目的：介绍肾移植术后高血压药物治疗的具体方法和治疗中需要注意的问题。方法：对肾移植术后高血压的病因学进行了分析，结合目前常用的各类别抗高血压药物的作用特点，针对移植后高血压的特殊病因和肾移植病人特殊的病理生理状况，提出肾移植术后高血压药物治疗的具体策略。结果：治疗中需要了解不同抗高血压药物的作用特点，并考虑其对移植物可能造成的不利影响。还要考虑这些药物与免疫抑制药物之间的潜在药物相互作用，对于肾移植术后的其他并发症，如糖尿病、高胆固醇血症、胰岛素耐受、缺血性心脏病等影响也必须加以考虑。结论：高血压是肾移植病人移植物功能衰竭、心血管发病和死亡的重要危险因素，需要针对不同病因和情况合理使用抗高血压药物。     

肾移植术后护理干预的研究

目的：探讨护理干预对肾移植出院患者生理、心理和社会功能的作用。方法：选取31例肾移植手术1个月且康复出院的患者,出院后常规治疗、护理基础上进行康复运动护理干预。按干预前和干预3个月后两个阶段收集资料,包括患者的一般情况、生理指标和生活质量状况等资料,并进行统计学分析。结果：干预后生活质量总得分及各维度得分、肺部感染率于干预前比较,差异有统计学意义僻〈0．05）,BMI、血压、血糖、甘油三酯（TG）的差异有统计学意义（P〈0．05）。而社会功能、心率、血肌酐的差别无统计学意义（P〉0．05）。结论：肾移植出院患者康复运动护理干预方案是安全可行、有效的。     

ABCC2基因多态性与肾移植受者环孢素所致肝功能异常的相关性研究

目的:研究肾移植术后患者多药耐药相关蛋白(MRP2/ABCC2)基因多态性对环孢素(CsA)肝功能异常的影响.方法:入选的339例肾移植受者均采用CsA治疗,检测患者rs717620(A/G)和rs2273697 (G/A)多态性的基因型.此外,采用荧光偏振免疫法检测患者的CsA血药浓度,根据肾移植患者发生肝脏损伤的情况分为3组.结果:rs717620和rs2273697突变等位基因发生频率分别为38.89％和10.72％.ABCC2基因rs717620位点的G突变等位基因与CsA肝功能异常的发生密切相关,与对照组比较,CsA肝功异常组的GG基因型发生频率明显升高(P＜0.05),AA基因型发生频率明显降低(P＜0.05).ABCC2基因rs2273697多态性与CsA肝功异常的发生无明显相关.基因型分析结果显示,这两个多态性对CsA谷浓度均无明显相关性,但rs2273697多态性对ALT和AST检测值有明显影响.对于ABCC2基因rs717620而言,GG基因型纯合子携带者的发病风险比AA型纯合子携带者高6倍(OR=6.960,95％ CI.1.636～29.610,P＜0.01).单倍体分析结果显示,与AA-AA基因型个体相比,GG-GG和GG-GA基因型个体移植术后发生CsA肝功异常的风险分别增加5.909倍和13.333倍.结论:ABCC2基因rs717620位点多态性与CsA肝功异常有明显相关性.ABCC2基因单倍体各基因型中,GG-GG和GG-GA单倍体基因型是肾移植术后发生CsA肝功异常的危险基因因素.     

Influence of CYP3A5 genetic polymorphism on cyclosporine A metabolism and elimination in Chinese renal transplant recipients

AIM: To investigate whether the CYP3A5*3 polymorphism would affect cyclosporine A (CsA) metabolism in Chinese renal transplant patients. METHODS: The CYP3A5*3 genotype was determined in Chinese renal transplant recipients using polymerase chain reaction and amplification of specific alleles (PCR-ASA). The concentrations of CsA and metabolites were separately measured by fluorescence polarization immunoassay and dose-adjusted trough concentrations and metabolic ratio (MR) values were calculated. RESULTS: The trough concentrations adjusted with the dose was significantly higher in the wild allele carriers compared to both the homozygous (*3*3) and heterozygous variants (*1*3). However, no significant difference was found for the dose-adjusted metabolite concentrations. The MR values for the 3 genotype groups were as follows: 0.92+/-0.62 for CYP3A5*3/ *3 (n=14), 0.99+/-0.51 for CYP3A5*1/*3 (n=15), and 1.45+/-0.62 for CYP3A5*1/*1 (n=9), respectively. Post hoc comparisons showed that only the MR values between the CYP3A5*3/*3 group and the CYP3A5*1/*1 group were significantly different. CONCLUSION: The CYP3A5*3 polymorphism exerted little effect on cyclosporine metabolism. The MR may be a more accurate indicator for therapeutic drug monitoring, considering its integrated information on body exposure of both parent drugs and metabolites.     

肾移植术后肺部感染的药物治疗

肺部感染是肾移植术后常见并发症,救治不利时可危及生命。治疗的关键在于根据不同时期、不同菌群感染正确选择和应用抗菌药物。本文对抗菌药物在肾移植术后肺部感染的应用进行综述,以期为疾病的预防及治疗提供参考。     

Cardiovascular complications of immunosuppressive agents in renal transplant recipients

Fatal and nonfatal cardiovascular events are the most important cause of graft loss in patients with a functioning graft following transplantation. The available data indicate that transplant patients have a high prevalence of hypertension, hyperlipidaemia and new onset diabetes mellitus after transplantation. The aetiology and pathogenesis of post-transplant hypertension, hyperlipidaemia and diabetes are multifactorial. In addition, disease of the native kidney and recurrence of renal disease can contribute to the development of cardiovascular disease in transplant recipients. Most transplant patients are at risk of clinically important drug-drug interactions involving immunosuppressive agents. Adverse reactions and drug-drug interactions should not be neglected when selecting an agent for treatment of cardiovascular risk factors in transplant recipients.     

他克莫司对尸肾移植患者糖代谢的影响

目的观察不同浓度的他克莫司(FK506)对尸肾移植患者糖代谢的影响。方法分析53例尸肾移植术后应用FK506为基础的免疫抑制剂治疗受者临床资料。结果53例尸肾移植患者随访12-24个月,9例发展为糖尿病。经调整FK506剂量,降低其全血谷值浓度,并减少泼尼松用量,口服降糖药物后7例血糖恢复正常,另2例应用胰岛素治疗。结论FK506是一种强效免疫抑制剂,应用时易发生移植后糖尿病,可通过调整FK506剂量,降低其浓度,减少泼尼松用量,并同时应用胰岛素治疗。     

Time-dependent clearance of mycophenolic acid in renal transplant recipients

AIMS: Pharmacokinetic studies of the immunosuppressive compound mycophenolic acid (MPA) have shown a structural decrease in clearance (CL) over time after renal transplantation. The aim of this study was to characterize the time-dependent CL of MPA by means of a population pharmacokinetic meta-analysis, and to test whether it can be described by covariate effects. METHODS: One thousand eight hundred and ninety-four MPA concentration-time profiles from 468 renal transplant patients (range 1-9 profiles per patient) were analyzed retrospectively by nonlinear mixed effect modelling. Sampling occasions ranged from day 1-10 years after transplantation. RESULTS: The pharmacokinetics of MPA were described by a two-compartment model with time-lagged first order absorption, and a first-order term for time-dependent CL. The model predicted the mean CL to decrease from 35 l h(-1) (CV = 44%) in the first week after transplantation to 17 l h(-1) (CV = 38%) after 6 months. In a covariate model without a term for time-dependent CL, changes during the first 6 months after transplantation in creatinine clearance from 19 to 71 ml min(-1), in albumin concentration from 35 to 40 g l(-1), in haemoglobin from 9.7 to 12 g dl(-1) and in cyclosporin predose concentration from 225 to 100 ng ml(-1) corresponded with a decrease of CL from 32 to 19 l h(-1). Creatinine clearance, albumin concentration, haemoglobin and cyclosporin predose concentration explained, respectively, 19%, 12%, 4% and 3% of the within-patient variability in MPA CL. CONCLUSIONS: By monitoring creatinine clearance, albumin concentration, haemoglobin and cyclosporin predose concentration, changes in MPA exposure over time can be predicted. Such information can be used to optimize therapy with mycophenolate mofetil.