Impact of UGT2B7 and ABCC2 genetic polymorphisms on mycophenolic acid metabolism in Chinese renal transplant recipients.

AIM: To evaluate genetic variants affecting mycophenolic acid (MPA) metabolism in Chinese renal transplant recipients. METHODS: Total 11 SNPs of UGT1A9, UGT1A8, UGT2B7, ABCC2, ABCG2 and SLCO1B3 were genotyped in 408 Chinese renal transplant recipients. Associations between SNPs and MPA concentration/dose ratio (C0/D) were analyzed using different genetic models. Multivariate linear regression was used to analyze associations between log (C0/D) and clinical factors. Results: After adjustment by clinical factors, UGT2B7 rs7662029 was associated with log (C0/D) using a dominant (p = 0.041) and an additive (p = 0.038) model, ABCC2 rs717620 was associated with log (C0/D) using a recessive model (p = 0.019). Using additive model, SNP-SNP interactions were identified (p = 0.002) between ABCC2 rs717620 and UGT1A9 rs2741049, with interactions (p = 0.002) between ABCC2 rs717620 and UGT1A8 rs1042597. Age, albumin and serum creatinine were associated with log (C0/D). CONCLUSION: rs7662029 and rs717620 may affect MPA pharmacokinetics. SNP-SNP interactions and clinical factors may have significant effects on MPA metabolism.

Tacrolimus in preventing transplant rejection in Chinese patients--optimizing use.

Tacrolimus is a product of fermentation of Streptomyces, and belongs to the family of calcineurin inhibitors. It is a widely used immunosuppressive drug for preventing solid-organ transplant rejection. Compared to cyclosporine, tacrolimus has greater immunosuppressive potency and a lower incidence of side effects. It has been accepted as first-line treatment after liver and kidney transplantation. Tacrolimus has specific features in Chinese transplant patients; its in vivo pharmacokinetics, treatment regimen, dose and administration, and adverse-effect profile are influenced by multiple factors, such as genetics and the spectrum of primary diseases in the Chinese population. We reviewed the clinical experience of tacrolimus use in Chinese liver- and kidney-transplant patients, including the pharmacology of tacrolimus, the immunosuppressive effects of tacrolimus versus cyclosporine, effects of different factors on tacrolimus metabolism on Chinese patients, personalized medicine, clinical safety profile, and patient satisfaction and adherence. This article provides guidance for the rational and efficient use of tacrolimus in Chinese organ-transplant patients.

Impact of the CYP3A5, CYP3A4, COMT, IL-10 and POR genetic polymorphisms on tacrolimus metabolism in Chinese renal transplant recipients.

Tacrolimus is a widely used immunosuppressive drug for preventing the rejection of solid organ transplants. The efficacy of tacrolimus shows considerable variability, which might be related to genetic variation among recipients. We conducted a retrospective study of 240 Chinese renal transplant recipients receiving tacrolimus as immunosuppressive drug. The retrospective data of all patients were collected for 40 days after transplantation. Seventeen SNPs of CYP3A5, CYP3A4, COMT, IL-10 and POR were identified by the SNaPshot assay. Tacrolimus blood concentrations were obtained on days 1-3, days 6-8 and days 12-14 after transplantation, as well as during the period of the predefined therapeutic concentration range. Kruskal-Wallis test was used to examine the effect of genetic variation on the tacrolimus concentration/dose ratio (C 0/D) at different time points. Chi-square test was used to compare the proportions of patients who achieved the target C 0 range in the different genotypic groups at weeks 1, 2, 3 and 4 after transplantation. After correction for multiple testing, there was a significant association of C 0/D with CYP3A5*3, CYP3A4*1G and CYP3A4 rs4646437 T>C at different time points after transplantation. The proportion of patients in the IL-10 rs1800871-TT group who achieved the target C 0 range was greater (p = 0.004) compared to the IL-10 rs1800871-CT and IL-10 rs1800871-CC groups at week 3 after transplantation. CYP3A5*3, CYP3A4 *1G, CYP3A4 rs4646437 T>C and IL-10 rs1800871 C>T might be potential polymorphisms affecting the interindividual variability in tacrolimus metabolism among Chinese renal transplant recipients.

Tacrolimus dosing in Chinese renal transplant recipients: a population-based pharmacogenetics study.

OBJECTIVES: The aims of this study were to examine the effects of genetic and clinical factors on the maintenance dose of tacrolimus in patients following renal transplantation and to develop a tacrolimus-dosing model that could be combined with associated factors. PATIENTS AND METHODS: This study included 142 renal transplant recipients who received tacrolimus as immunosuppressive agent. CYP3A5, MDR1 and NR1I2 gene polymorphisms were identified based on the SNaPshot assay. The relationship between the genetic and clinical factors and tacrolimus maintenance dose as well as between dose-corrected tacrolimus concentration was examined. RESULTS: CYP3A5 genotype, body weight, haematocrit, haemoglobin and total bilirubin significantly influenced the maintenance tacrolimus dose. The tacrolimus-dosing model derived from linear regression model accounted for 40.5% of total variations in the tacrolimus maintenance dose. CONCLUSIONS: A pharmacogenetics-based dosing model has been developed for the prediction of the tacrolimus maintenance dose in renal transplant recipients. This model may be useful in helping clinicians prescribe the initial tacrolimus dose with greater safety and effectiveness.

Simultaneous detection of CYP3A5 and MDR1 polymorphisms based on the SNaPshot assay.

BACKGROUND: The 6986A>G polymorphism for CYP3A5 and the -129T>C, 1236C>T, 2677G>T/A, and 3435C>T polymorphisms for MDR1 are considered the major genetic factors affecting a range of drugs' metabolism and transport. Simultaneous genotyping of these five polymorphisms would be useful for estimating the therapeutic effects of their related drugs. SUBJECTS AND METHODS: We have described a SNaPshot assay that can simultaneously detect all the five polymorphisms based on multiplex PCR and minisequencing reaction. A total of 168 unrelated Chinese DNA samples were used to establish and evaluate the assay. RESULTS: The different genotypes of the five polymorphisms could be determined by peak retention time and colors. DNA sequencing was performed on samples randomly selected from each of the genotype groups detected by SNaPshot assay, and the results indicated 100% concordance. CONCLUSION: The SNaPshot assay for the CYP3A5 and MDR1 five polymorphisms detection was accurate, automated, and cost-effective.

[Long-term survival of high-risk kidney transplant patients].

OBJECTIVE: To summarize the experiences in high-risk renal transplant recipients for ketter long-term survival. METHODS: From April 1991 to December 2008, a total of 921 kidney recipients with high-risk factors were divided into six groups as following: (1) pediatric patients (< 18 years old) (GI, n = 34); (2) retransplant recipients (GII, n = 169); (3) high sensitized patients (PRA> 30% or peak PRA > 50%)(GIII, n = 35); (4) elderly recipients (> 60 years old) (GIV, n = 297); (5) diabetic patients (GV, n = 112); (6) patients with HBV/HCV infection or HBV/HCV carrier (GVI, n = 274). Each group was compared to a control of 807 recipients without any above risk factor for patient and graft survival at 1, 3 and 5 years. Incidences of acute rejection (AR), chronic rejection (CR) and complication were analyzed and compared respectively between the studied subjects and the control group as well. RESULTS: Compared with the control group, patient/graft survivals were lower in GII, GIII and GVI (all P < 0.05), GIV had worse patient survival (P < 0.05); AR and CR incidences were greater in GI and GIII (all P < 0.05); GIV, GV and GVI had more complications. CONCLUSIONS: This study suggests the benefits for long-term outcome in high-immunological risk renal transplant recipients of low acute selection incidence rate, and reduction of complication incidences is the key to long term results for non-immunological high risk recipients.

[Combined assay of soluble CD30 and hepatocyte growth factor for diagnosis of acute renal allograft rejection].

OBJECTIVE: To study the value of detection of both preoperative soluble CD30 (sCD30) and hepatocyte growth factor (HGF) level 5 days after transplantation in the diagnosis of acute rejection of renal allograft. METHODS: Preoperative serum sCD30 levels and HGF level 5 days after transplantation were determined in 65 renal-transplant recipients using enzyme-linked immunosorbent assay. The recipients were divided according to the sCD30 levels positivity. Receiver operating characteristic (ROC) curves were used to assess the value of HGF level on day 5 posttransplantation for diagnosis of acute renal allograft rejection, and the value of combined assay of the sCD30 and HGF levels was also estimated. RESULTS: After transplantation, 26 recipients developed graft rejection and 39 had uneventful recovery without rejection. With the cut-off value of sCD30 of 120 U/ml, the positivity rate of sCD30 was significantly higher in recipients with graft rejection than in those without (61.5% vs 17.9%, P<0.05). Recipients with acute rejection showed also significantly higher HGF levels on day 5 posttransplantation than those without rejection (P<0.05). ROC curve analysis indicated that HGF levels on day 5 posttransplantation was a good marker for diagnosis of acute renal allograft rejection, and at the cut-off value of 90 ug/L, the diagnostic sensitivity was 84.6% and specificity 76.9%. Evaluation of both the sCD30 and HGF levels significantly enhanced the diagnostic accuracy of acute graft rejection. CONCLUSION: Combined assay of serum sCD30 and HGF levels offers a useful means for diagnosis of acute renal allograft rejection.

[Association between transforming growth factor beta-1 gene polymorphism and chronic allograft nephropathy].

OBJECTIVE: To investigate the association between transforming growth factor beta-1 (TGF-beta1) gene polymorphism and chronic allograft nephropathy (CAN). METHODS: Fifty patients with failed renal allografts and clinically and histopathologically confirmed CAN were enrolled in this study along with another 50 renal transplant recipients with normal graft function. The DNA extracted from whole blood of the patients was amplified with PCR with sequence-specific primers for determining TGF-beta1 genotypes (position +869, codon 10 and position +915, codon 25). According to documented descriptions, the patients were classified into high and moderate-to-low cytokine production genotypes. The distribution frequencies of high production genotypes was then compared between CAN and non-CAN groups. To eliminate interference in the analysis of the association between TGF-beta1 polymorphism and CAN, other possible risk factors for CAN were screened, including the patients' gender, age, HLA match, delayed graft function, acute rejection, immunosuppressive regimen, cytomegalovirus infection, hypertension, and high cholesterol. RESULTS: CAN patients showed significantly greater proportion of high cytokine production genotype than the non-CAN group [70% (35/50) vs 38% (19/50), Chi(2)=10.306, P=0.001). Of the screened risk factors for CAN, only acute rejection showed some difference between the two groups, but analysis after subgrouping according to acute rejection did not suggest its influence on CAN, which supports the result that the rate of high production genotype was significantly higher in CAN group than in the non-CAN group. CONCLUSION: Most CAN patients have high TGF-beta1 production genotype, which might be a risk factor for CAN after renal transplantation. TGF-beta1 genotyping can be of value in predicting the risk of CAN after renal transplantation.

[Clinical observation on long-term surviving patients after combined abdominal organ transplantation].

OBJECTIVE: To summarize the treatment experience of long-term surviving patients after combined abdominal organ transplantation. METHODS: From October 2001 to January 2005, 19 patients received combined abdominal organ transplantation in Nanfang Hospital, including 6 with simultaneous kidney-pancreas transplantation (SKPT), 12 with combined liver-kidney transplantation (CLKT), and 1 with simultaneous liver-pancreas transplantation (SLPT). The periods of follow up were from 6 months to 3 years and 8 months. Summarize primary diseases of the patients, factors which impacted on patients long-term survival rate, and immunological characteristics of combined abdominal organ transplantation. RESULTS: All of 19 transplant cases were performed successfully. Among then, 18 were followed up; 16 survived till now; 2 patients undergoing liver-kidney transplantation were dead, one of which died from myocardial infarction in the 18 months after operation, and one died from cytomegalovirus in infection of lung in 13 months; 1 liver-kidney transplantation patient and 2 pancreas-liver transplantation patients experienced acute rejection once; 2 patients were found nephrotoxicity. Among the 18 patients, 4 patients' survival time were over 3 years, 7 over 2 years, 6 over 1 year, 1 over 10 months. CONCLUSIONS: Combined abdominal organ transplantation is effective for treatment of two abdominal organ failure diseases. Factors which impact on patients long-term surviving include choosing suitable recipient, high quality of donated organ, avoidance of surgical complication, the history of myocardial infarction before operation, immunosuppressive regime and virus infection late after transplantation. Combined abdominal organ transplantation has some different immunological characteristics from single organ transplantation.

[Simultaneous liver-pancreas-duodenum transplantation: one case report and review of the literature].

OBJECTIVE: To investigate the effect of treatment on end-stage liver disease and type-I diabetes mellitus with simultaneous liver-pancreas-duodenum transplantation. METHOD: In September 2003, one patient with chronic hepatitis B, liver cirrhosis, hepatic cellular cancer, and insulin-dependent diabetes received simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantation. Liver and pancreas graft function was monitored after transplantation. RESULTS: The function of pancreas allograft was recovered immediately and the patient became insulin-independence postoperatively. The liver allograft was experienced an acute rejection episode and reversed by intravenous bolus methylprednisolone. The recipient was currently liver disease-free and insulin-free more than 21 months. CONCLUSIONS: The simultaneous liver-pancreas-duodenum transplantation is an effective method in the treatment of end-stage liver disease and type-I diabetes mellitus.

[Deep venous thrombosis in the lower extremities following renal transplantation: causes and management].

OBJECTIVE: To investigate the causes, prevention measures and treatment of deep venous thrombosis in the lower extremities (LDVT) following renal transplantation. METHOD: Thirty-eight renal transplant recipients who developed LDVT following the transplantation were analyzed for the causes, evidence for diagnosis, prevention measures and treatment of LDVT. RESULTS: The 38 cases were diagnosed by B-mode ultrasound and systemic medical history review and after timely and effective therapy, all the patients recovered between 3 to 20 d, showing evidence of establishment of efficient collateral circulation as found in color Doppler ultrasound examination. CONCLUSION: Following renal transplantation, the recipients are exposed to greater risks of developing LDVT, for which B-mode ultrasound provides the most effective diagnosis. The patients generally respond well to timely interventions with anticoagulation, clot removal and thrombolysis, and preventive measures are indicated in those at high risk of LDVT following transplantation.

[Simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantation in a diabetic patient with end-stage liver disease].

OBJECTIVE: To study the effect of combined transplantation of the liver and the pancreas in diabetic patients with end-stage liver disease, and explore the optimal surgical procedure. METHODS: Simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantations were performed in a patient diagnosed as having chronic hepatitis B, hepatocirrhosis, hepatic cellular cancer, and insulin-dependent diabetes. Immunosuppression therapy utilized prednisone, tacrolimus (FK506), mycophenolate mofetil (MMF), and simulect. The function of the liver graft, serum amylase and lipase, blood glucose, and C-peptide were monitored after transplantation. RESULTS: Insulin was withdrawn at the 6th day after operation, good liver allograft functional recovery was achieved, without such complications as pancreatitis, thrombosis, and localized infections. CONCLUSION: End-stage liver disease with concomitant insulin-dependent diabetes is the indication for combined liver-pancreas transplantations, for which simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantations may constitute the optimal surgical approaches as the primary choice.

[Combined liver-kidney transplantation in a senior patient].

OBJECTIVE: To study the surgical techniques, perioperative management, management of infections and graft rejection in patients with combined liver-kidney transplantation (CLKT). METHODS: CLKT was performed in a 66-year-old patient with alcoholic liver cirrhosis and uremia. Lavage in situ with University of Wisconsin (UW) solution of the donor organs and en hoc resection was performed. Orthotopic liver transplantation (OLT) and routine kidney transplantation were respectively carried out. Immunosuppression therapy consisted of tacrolimus (FK506), antithymocyte globulin (ATG), mycophenolate mofetil (CellCept, MMF) and corticosteroid. RESULTS: Both of the transplanted organs rapidly recovered normal functions after operation, and acute rejection of the liver graft occurred on day 10 after operation but was controlled after methylprednisolone pulse therapy. The patient fully recovered and was discharged from hospital on day 29 after operation. CONCLUSIONS: CLKT is effective against both liver and renal function failure. Well-matched HLA tissue typing, proficient surgical skills, adequate application of immunosuppressants and effective management of postoperative complications are crucial for successful CLKT.