Is there additional effect of MTHFR C677T mutation on lipid abnormalities in renal allograft recipients?

BACKGROUND: The MTHFR C677T mutation and elevated atherogenic lipoprotein levels are known as cardiovascular risk factors in patients with renal transplantation treated with cyclosporine (CsA). The aim of the present study was to eveluate the contribution of MTHFR C677T mutation to the risk of dyslipidemia in renal transplant recipients. We also studied the effect of the MTHFR-C677 T genotype on transplant survival. METHODS: The study included 29 nondiabetic renal transplant recipients and 27 healthy controls. MTHFR C677T genotypes were determined by PCR and RFLP techniques. Biochemical parameters were measured in a computerized autoanalyzer. RESULTS: In the patient group, the distribution of the CC, CT, and TT genotypes was 44.8% (n = 13), 37.9% (n = 11), and 17.2% (n = 5), respectively. The frequencies of the C and T alleles were 0.64 and 0.36, respectively. Subjects with the T allele had the highest levels of TC (P <.05) and LDL-C (P <.05); subjects with the CC genotype had the lowest. CONCLUSIONS: We observed that the MTHFR T allele has an unfavorable effect on serum lipid profile, leading to a rise in the total and LDL cholesterol concentrations. Thus, we believe that MTHFR C allele has a protective effect and MTHFR T allele has a detrimental effect on the serum lipid profile.     

Donor G protein beta3 subunit 825TT genotype is associated with reduced kidney allograft survival.

Recent studies have identified a novel polymorphism (C825T) of the gene encoding the beta3 subunit of heterotrimeric G proteins (Gbeta3), associated with enhanced activation of G proteins, which appears to be more common in hypertensive patients. In the present study, the relationship between this genetic variant and kidney allograft survival was examined over the first 3 yr after transplantation, in 320 consecutive Caucasian patients recruited from the Berlin-Steglitz transplantation center between 1988 and 1993. Clinical parameters, transplantation data, and details of graft survival were retrieved from clinical records. After multivariate adjustment for covariates (Cox hazard regression), the Gbeta3 825TT donor-genotype was associated with a significantly decreased graft survival representing a relative risk of graft loss of 2.2 (95% confidence interval, 1.1 to 4.8) compared to TC and CC grafts within the observation period. This association between donor TT genotype and graft survival remained stable even after stepwise exclusion of covariates from the multivariate model. In contrast, there was no significant relationship between recipient genotype and allograft function. These findings indicate that individuals receiving renal allografts from donors homozygous for the Gbeta3-825T allele may have an increased risk of developing allograft failure. Additional studies on the role of this genetic marker as well as the role of pertussis toxin-sensitive G proteins in the development of chronic rejection appear warranted.     

Angiotensinogen and plasminogen activator inhibitor-1 gene polymorphism in relation to chronic allograft dysfunction

Chronic allograft dysfunction (CAD) is the most common cause of allograft failure in the long-term, and current immunologic strategies have little effect on this condition. The renin-angiotensin system (RAS) plays important roles progression of chronic renal disease. It is thought that plasminogen activator inhibitor-1 (PAI-1) functions in the RAS, in addition to involvement in thrombotic risk and fibrosis. This study investigated possible links between angiotensinogen (AGT) genotypes (M235T/MM, MT, TT) and PAI-1 genotypes (4G4G, 4G5G, 5G5G) and CAD assessments of both types of polymorphism were performed in 82 renal allograft recipients. One hundred healthy subjects were also investigated for AGT polymorphism, and 80 healthy subjects for PAI-1 polymorphism. Genotypes were determined using polymerase chain reaction (PCR) sequence-specific primers, and PCR followed by restriction fragment length polymorphism analysis. Kidney recipients with CAD had significantly lower frequencies of the MM genotype and the M allele than the recipients without CAD (p < 0.05 and <0.001). The transplant recipients with CAD also had significantly lower frequencies of the 5G5G genotype and the 5G allele than those without CAD (p < 0.001 and <0.05). Determination of AGT M235T and PAI-1 genotypes prior to transplantation may help identify patients who at risk for chronic renal transplant dysfunction.     

The effect of MDR1 (ABCB1) polymorphism on the pharmacokinetic of tacrolimus in Turkish renal transplant recipients

There is marked interindividual variability in trough blood levels of tacrolimus (TRL) following standard dosing. TRL is a substrate for P-glycoprotein (P-gp), the product of the multidrug resistance-1 (MDR1)(ABCB1) gene. P-gp acts as a membrane efflux pump, which affects TRL absorption from the gut. Some of the single nucleotide polymorphisms (SNP) of ABCB1 gene are associated with pharmacokinetic characteristics of TRL. The objective of this study was to determine the role of ABCB1 C3435T polymorphism on TRL dose requirements, trough values and dose-adjusted trough TRL concentrations among Turkish renal transplant recipients. Renal transplant recipients receiving TRL (n=92) were genotyped for ABCB1. TRL daily doses, trough concentrations, dose-adjusted trough concentrations, demographic features, and clinical data were obtained at 1, 6, and 12 months after renal transplantation. The frequency of the ABCB1 3435 CC genotype was 30.4%, whereas 47.8% of patients were 3435 CT and 21.7% of patients were 3435 TT. TRL daily doses were significantly lower among patients with the 3435 TT genotype at months 1 and 6. At 6 and 12 months after transplantation patients who were homozygous for the ABCB1 3435 CC showed significantly lower dose-adjusted trough TRL concentrations compared with subjects of 3435 TT and CT genotypes. Knowledge of ABCB1 genotype may be useful to adjust the optimal dose of TRL in transplant patients, thereby rapidly achieving target concentrations.     

Investigation of PNPLA3 and IL28B Genotypes on Diabetes and Obesity After Liver Transplantation: Insight Into Mechanisms of Disease

To identify genetic risks for obesity and diabetes postliver transplantation (LT), LT recipients underwent genotyping for IL28B rs12979860 (n = 295) and PNPLA3 rs738409 (n = 205) polymorphism in both donors and recipients. The development of obesity and diabetes/impaired fasting glucose (IFG) was determined 1–5 years post‐LT. Recipient PNPLA‐3 genotype was independently associated with obesity (BMI > 30) at 3 years posttransplant (genotype CC 33.7%, CG 48.3% and GG 82.4%, p = 0.002), with an odds ratio (OR 2.54, CI 1.38–4.66, p = 0.003), associated with the G allele. Diabetes/IFG diagnosed within 5 years posttransplant associated with PNPLA‐3 non‐CC genotype (HR 1.59, 1.12–2.26, p = 0.010), but not IL28B TT genotype (HR 1.46, 0.94–2.27, p = 0.092). No genotype variable was independently predictive of diabetes/IFG. The combination of PNPLA‐3 non‐CC and IL28B TT genotype was associated with increased risk of diabetes/IFG compared to PNPLA‐3 CC, IL28B non‐TT (HR 2.64, CI 1.30–5.39, p = 0.008). Donor genotypes were not associated with any of the outcomes analyzed. In conclusion, PNPLA‐3 non‐CC genotype is associated with posttransplant obesity but not independently with diabetes/IFG. The lack of donor related risk suggests a peripheral rather than central mechanism of insulin resistance in liver transplant recipients.     

Effect of MTHFR 677C>T on plasma total homocysteine levels in renal graft recipients

BACKGROUND: Hyperhomocysteinemia is an established, independent risk factor for vascular disease morbidity and mortality. The 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T has been shown to result in increased total homocysteine concentrations on the basis of low folate levels caused by a decreased enzyme activity. The effect of this polymorphism on total homocysteine and folate plasma levels in renal transplant patients is unknown. METHODS: We screened 636 kidney graft recipients for the presence of the MTHFR C677T gene polymorphism. The major determinants of total homocysteine and folate plasma concentrations of 63 patients, who were identified to be homozygous for this gene polymorphism compared with heterozygotes (N = 63), and patients with wild-type alleles (N = 63), who were matched for sex, age, glomerular filtration rate (GFR), and body mass index, were identified by analysis of covariance. The variables included sex, age, GFR, body mass index, time since transplantation, folate and vitamin B12 levels, the use of azathioprine, and the MTHFR genotype. To investigate the impact of the kidney donor MTHFR genotype on total homocysteine and folate plasma concentrations, a similar model was applied in 111 kidney graft recipients with stable graft function, in whom the kidney donor C677T MTHFR gene polymorphism was determined. RESULTS: The allele frequency of the C677T polymorphism in the MTHFR gene was 0.313 in the whole study population [wild-type (CC), 301; heterozygous (CT), 272; and homozygous mutant (TT), 63 patients, respectively] and showed no difference in the patient subgroups with various renal diseases. The MTHFR C677T gene polymorphism significantly influenced total homocysteine and folate plasma concentrations in renal transplant recipients (P = 0.0009 and P = 0.0002, respectively). Furthermore, a significant influence of the GFR (P = 0.0001), folate levels (P = 0.0001), age (P = 0.0001), body mass index (P = 0.0001), gender (P = 0.0005), and vitamin B12 levels (P = 0.004) on total homocysteine concentrations was observed. The donor MTHFR gene polymorphism had no influence on total homocysteine and folate levels. Geometric mean total homocysteine levels in patients homozygous for the mutant MTHFR allele were 18.6 micromol/liter compared with 14.6 micromol/liter and 14.9 micromol/liter in patients heterozygous for the MTHFR gene polymorphism and those with wild-type alleles (P < 0.05 for TT vs. CT and CC). Geometric mean folate levels were lower in CT and TT patients (11.2 and 10.2 nmol/liter) compared with CC patients (13.6 nmol/liter, P < 0.05 vs. CT and TT). CONCLUSIONS: This study demonstrates that homozygosity for the C677T polymorphism in the MTHFR gene significantly increases total homocysteine concentrations and lowers folate levels in kidney graft recipients, even in patients with excellent renal function (GFR more than median). These findings have important implications for risk evaluation and vitamin intervention therapy in these patients who carry an increased risk for the development of cardiovascular disease.     

Influence of uridine diphosphate-glucuronosyltransferases (1A9) polymorphisms on mycophenolic acid pharmacokinetics in patients with renal transplant

Background: There are differences in pharmacokinetic of mycophenolic acid among individuals. The UGT1A9 enzyme is of special interest since it is the main enzyme involved in the glucuronidation of MPA. Single nucleotide polymorphisms in the UGT1A9 gene may be responsible for individual differences in the pharmacokinetics of MPA. The aim of this study was to explain MPA pharmacokinetics in UGT1A9 1399 C?>?T polymorphisms in Turkish renal transplant patients.

Patients and methods: One hundred and twenty-five living-donor transplant recipients and 100 healthy control subjects underwent UGT1A9 1399 C?>?T genotyping using polymerase chain reaction–restriction fragment length polymorphism. Concentrations of MPA were determined with Cloned Enzyme Donor Immunoassay (CEDIA). Besides that, all the patients were monitored for acute rejection and graft function during the study period.

Results: The UGT1A9 1399 C?>?T CC, CT, and TT genotype frequencies among patients were, respectively, 68.0%, 23.2%, and 8.8%. The CC, CT, and TT genotype frequencies among controls were, respectively, 63.0%, 23.0%, and 14.0%. There was no significant difference between patients and controls (p?=?.480, p?=?.999, p?=?.286, respectively). At first month, respectively, through blood concentrations of MPA were significantly higher in UGT1A9 1399 C?>?T TT carriers than in CT and CC carriers (p?=?.046). The doses for these patients were lower at first month (p?=?.021). Acute rejection episodes were not associated with the CC vs CT or TT genotypes (p?=?.064).

Conclusions: Our results demonstrated a correlation between the UGT1A9 1399 C?>?T polymorphism and MPA pharmacokinetics among renal transplant patients. Determination of UGT1A9 polymorphism may help to achieve target of MPA blood concentrations.     

Effect of apolipoprotein polymorphisms in renal transplant recipients

Cardiovascular disease (CVD) is the main cause of mortality among long-term renal transplant recipients (RTR). On the other hand, allograft chronic nephropathy is the primary cause of graft loss among long-term RTR. Hyperlipidemia is a predisposing factor for both conditions. Polymorphisms of the apolipoproteins modulate lipid metabolism. The aim of the study was to evaluate the effect of apo A-I, apo A-IV and apo C-III genotypes on the long-term results of renal transplantation. Clinical assessment (renal allograft and patient survival) and genotyping for apo A-I (+83C/T), apo C-III (Sst I), and apo A-IV (Thr347Ser and Gln360His) polymorphisms were evaluated in 516 kidney transplant patients and correlated with the clinical evolution over 12 months. The distribution of the apo A-I (+83C/T) polymorphisms was: CC 91.9%, CT 7.9%, and TT 0.2%. The apo C-III genotype showed: S1S1 84.4%, S1S2 15.2%, and S2S2 0.4%. The apo A-IV (Pvu II) polymorphism was: GG 82%, GT 18%, and 0% TT. Finally, the frequency of apo A-IV (Hinf I) polymorphism was: AA 69%, AT 27%, and TT 4%. The frequency of polymorphisms was similar between men and women. In conclusion, there was no significant influence of apolipoprotein polymorphisms on renal and patient survival.     

Hypertension after renal transplantation and polymorphism of genes involved in essential hypertension: ACE, AGT, AT1 R and ecNOS

BACKGROUND: Arterial hypertension (HT), secondary to cyclosporine A (CsA) used as main immunosuppressive treatment in renal transplantation (RTx), is very frequent (70%), usually severe and explained mostly by vasoconstriction of the glomerular afferent arteriole with secondary sodium and water retention. MATERIAL AND METHODS: In a retrospective study, we have analyzed 294 consecutive recipients receiving a first renal cadaveric allograft and all treated with CsA (the majority with triple therapy). We studied, by molecular biology, the polymorphism of genes previously implicated in essential HT such as: angiotensin-converting enzyme (ACE: II, ID and DD), angiotensinogen (AGT: MM, MT and TT), angiotensin II type 1 receptor (AT1-R: AA, AC and CC) and endothelial constitutive nitric oxide synthase (ecNOS: aa, ab and bb), and correlated the data to the prevalence and severity of post-Tx HT. This cohort included 195 (66%) males and 99 females with a mean age of 42 years at time of Tx. The presence and severity of post-Tx HT were indicated by initial persistent blood pressure over 140/90 mmHg with the need for at least one anti-hypertensive drug and by the number of anti-HT medications required to achieve its control. RESULTS: The distribution of the specific alleles and genotypes for ACE, AGT, AT1-R, and ecNOS was not different in transplant recipients compared to 181 controls. At 5 years post-Tx, the prevalence of HT was 72% (169 out of 235) among functioning grafts. There was no significant difference for ACE, AGT, AT1R and ecNOS genotypes distribution between hypertensive vs non-HT recipients. The number of anti-hypertensive drugs prescribed was not different among ACE, AGT, and AT1-R genotypes. However, the a allele and the non-bb genotype (aa + ab) for ecNOS were significantly (p = 0.001) associated with a less severe HT, needing fewer anti-HT drugs. At 10 years post-Tx, the HT prevalence remained high 78% (67 out of 86) among functioning Tx. However, the limited numbers did not allow further correlation. CONCLUSIONS: This study produced mainly negative results except for ecNOS-a allele, which seems to protect against severe hypertension. The explanation remains speculative but probably relates to the known cyclosporine-induced upregulation of ecNOS gene and enzyme activity.     

Association of a CYP4A11 variant and blood pressure in black men

CYP4A11 arachidonic acid monooxygenase oxidizes endogenous arachidonic acid to 20-hydroxyeicosatetraenoic acid, a renal vasoconstrictor and natriuretic. Cyp4a deficiency causes hypertension in male mice, and a loss-of-function variant (T8590C) of CYP4A11 is associated with hypertension in white individuals. Hypertension and hypertensive renal disease are more common among black than white individuals, but the relationship between genetic variation at CYP4A11 and hypertension in black individuals is not known. This study tested the hypothesis that the CYP4A11 T8590C polymorphism is associated with higher BP or clinical outcomes in 732 black Americans with hypertensive renal disease participating in the African American Study of Kidney Disease (AASK). Men with the 8590CC genotype had significantly higher systolic BP (CC 156.5 +/- 22.6 versus 148.4 +/- 24.3 mmHg in CT and TT combined; P = 0.04) and pulse pressure (P = 0.04) at baseline; this association was not observed among women. In addition, this genotype was associated with higher systolic and diastolic BP at 36-mo follow-up among those randomly assigned to the lower BP arm of the AASK. Among all participants (or men but not women) with proteinuria, the 8590CC genotype was associated with an increased cumulative incidence of ESRD or death, controlling for randomization and clinical characteristics. In summary, the CYP4A11 8590CC genotype is associated with increased BP in black men with hypertensive nephrosclerosis and is associated with adverse clinical outcomes in those with baseline proteinuria. These data support a role for renal monooxygenases and 20-hydroxyeicosatetraenoic acid in the regulation of BP and renal function in men.     

GNB3 C825T等位基因多态性与原发性IgA肾病相关性研究

目的：研究G蛋白β3亚基（GNB3）C825T等位基因多态性与原发性IgA肾病（IgAN）的发生与病情进展。方法：病例组为216例原发性IgAN患者,对照组为200例健康志愿者。采用聚合酶链式反应-限制性片段长度多态性（PCR-RFLP）技术检测各组GNB3 825位点基因型。病例组分为高血压组与非高血压组;同时按基因型的不同将病例组分为TT组、CT组与CC组。结果：（1）病例组与对照组TT、CT、CC基因型频率分别为21.76%、54.63%、23.61%与18.00%、47.00%、35.00%,两组TT、TC、TT＋TC基因型与CC基因型分布频率存在统计学差异（P〈0.05）;病例组T等位基因分布频率高于对照组（49.07%vs 41.50%,P〈0.05）。（2）216例IgAN中,高血压组与非高血压组TT、CT、CC基因型频率分别为32.88%、49.31%、17.81%与16.09%、57.34%、26.57%（P〈0.05）。高血压组T等位基因频率较非高血压组明显增加（57.53%vs 44.76%,P〈0.05）。（3）病例组不同基因型携带者病理分级轻重无统计学差异（P〉0.05）。（4）病例组中不同基因型携带者在性别、年龄、体重指数、尿蛋白排泄量（〉1 g/d）、血肌酐水平、血胆固醇水平及三酰甘油水平无统计学差异（P〉0.05）,而高尿酸血症的发生存在统计学差异（P〈0.05）,TT组高尿酸血症患者较CT组及CC组高。结论：（1）病例组TT基因型和T等位基因频率较对照组明显增加,结果显示GNB3 825T等位基因可能与IgA肾病的发病有关,提示该基因可能与IgA肾病的遗传易感性相关。（2）GNB3 825T等位基因能影响IgA肾病患者高血压、高尿酸血症的发生。GNB3C825T等位基因多态性与IgA肾病发病及病情进展的相关机制有待进一步研究。     

Genetic association of FOXP3 gene polymorphisms with allograft rejection in renal transplant patients

Aim: FOXP3 gene is known to be important for regulatory T cell development and function, and is associated with the rejection of human kidney transplants. The present study was therefore conducted to determine the effect of FOXP3 polymorphisms on allograft rejection in renal transplant recipients. Methods: A total of 166 adult patients were categorized into either a Rejection group (65 patients) or a No rejection group (101 patients). Rs3761547, rs3761548 and rs2232365 variant alleles in the FOXP3 gene were genotyped using a TaqMan probe technique, and their relationships with rejection were investigated. Results: There was no significant difference in the genotype frequencies of rs3761547 and rs2232365 variants between patients with and without rejection history (P > 0.05). Binary logistic regression analysis showed that the rs3761548 AA genotype carriers were associated with about a fourfold greater risk for rejection compared with CC genotype (5 years post‐transplant: odds ratio 3.95, 95% confidence interval 1.27–12.29, P = 0.018). Kaplan–Meier analysis revealed a lower mean time to the first rejection in rs3761548 AA compared with CC genotype patients (Log rank = 4.303, P = 0.038). Multivariate Cox regression analysis indicated that rs3761548 AA genotype carriers have up to about a twofold (hazard ratio 2.37, 95% confidence interval 1.17–4.80, P = 0.017) higher risk for rejection than CC carriers. Conclusion: Our study suggests an association between FOXP3 rs3761548 polymorphisms and allograft rejection in renal transplantation. This association should be further proven in large prospective studies because of the small sample size and confounding factors in this retrospective study.     

Megsin 2093T-2180C haplotype at the 3' untranslated region is associated with poor renal survival in Korean IgA nephropathy patients

AIMS: Megsin is a mesangial cell-predominant gene which belongs to the serpin superfamily. The expression of megsin was upregulated and coincided with mesangial proliferation and extracellular matrix expansion in IgA nephropathy (IgAN). In the present study, we evaluated the influence of the C2093T and C2180T polymorphism within the 3' untranslated region (3'UTR) of megsin gene and its haplotypes on the development and progression of Korean IgAN patients. METHODS: Korean IgAN patients (n = 260) with a minimal follow-up of 4 years were recruited. Healthy subjects with normal renal function, normal urinalysis and normotension (n = 315) were included as controls. The polymorphisms were determined by the 5' nuclease allelic discrimination assay, and the haplotypes were constructed using the Phase program. RESULTS: The C2093T and C2180T genotype and allele frequencies were not different significantly between IgAN patients and controls. In C2093T polymorphism, patients with CC genotype showed a better renal survival than those with CT or TT genotypes by Kaplan-Meier analysis (p = 0.027). The megsin C2093T polymorphism remained an independent risk factor for progression (Cox regression model, HR for TT genotype: 3.52, 95% CI 1.69 - 7.34; HR for CT genotype: 2.15, 95% CI 1.30 - 3.57). In C2180T polymorphism, patients with TT genotype showed a better outcome than those with CC or CT genotypes (p = 0.025). The C2180T polymorphism was also an independent risk factor for progression (HR for CC genotype: 4.05, 95% CI 1.93 - 8.51; HR for CT genotype: 2.35, 95% CI 1.40 - 3.94). The two alleles showed linkage disequilibrium in phased haplotype. The patients with 2093T-2180C haplotype showed a poor renal survival compared to those with 2093C-2180T haplotype (p = 0.028). The haplotype remained an independent risk factor for progression (HR for 2093T-2180C haplotype: 2.01, 95% CI 1.44 - 2.81). CONCLUSIONS: Our results suggest that the 2093T-2180C haplotype at the 3'UTR of megsin gene is associated with rapid disease progression in Korean IgAN patients. This is the reverse of the results from the Chinese IgAN patients. Further studies are strongly needed to elucidate the reasons of disparity.     

Interplay between methylenetetrahydrofolate reductase gene polymorphism 677C→T and serum folate levels in determining hyperhomocysteinemia in heart transplant recipients

BACKGROUND: Homocysteine metabolism is often impaired in heart transplant recipients, and increased total homocysteine plasma levels may constitute a risk factor for the development of heart allograft vascular disease. Although 677C-->T transition in methylenetetrahydrofolate reductase (MTHFR) is associated with increased homocysteine levels in the general population, it is unclear whether MTHFR polymorphism influences homocysteine metabolism after heart transplant. METHODS: Homocysteine, serum folate, renal function, concentrations of cyclosporine and its metabolites, and MTHFR genotype were determined in 57 heart transplant recipients (age, 55 +/- 11 yr; 21% women; time from transplant, 48 +/- 42 months). RESULTS: Forty nine percent of the study population presented with hyperhomocysteinemia. Homocysteine was 17.1 +/- 5.9 micromol/liter, 19.4 +/- 4.9 micromol/liter, and 26.3 +/- 14.2 micromol/liter for genotypes CC, CT, and TT, respectively (p = 0.028, Kruskal-Wallis test). At multivariate analysis, MTHFR genotype was independently associated with homocysteine (p = 0.005). When the study population was divided into 2 groups accordingly to serum folate levels (above/below the median value of 6.1 ng/ml), MTHFR genotype remained a significant predictor of homocysteine only in patients with low serum folate (p = 0.048). CONCLUSIONS: This study demonstrates that hyperhomocysteinemia is frequent in heart transplant recipients and that the 677C-->T transition in the MTHFR gene independently and unfavorably influences homocysteine metabolism in this group of patients. Adequate folate intake may overcome genetic predisposition to hyperhomocysteinemia.     

VEGF -460 genotype plays an important role in progression to chronic kidney disease stage 5.

BACKGROUND: Changes in renal vasculature, with vascular and interstitial fibrosis, are hallmarks of progression to chronic kidney disease (CKD) stage 5. Vascular endothelial growth factor (VEGF) is a potent angiogenic and vascular permeability factor. Transforming growth factor-beta1 (TGF-beta1) plays a critical role in promoting extracellular matrix (ECM) deposition and fibrosis. This study investigates whether genetic polymorphisms of VEGF or TGF-beta1 are associated with (i) progressive decline in renal function in patients with glomerular disorders (cohort 1) and (ii) predisposition to CKD stage 5 in a separate group of renal transplant recipients with various primary diseases (cohort 2). METHODS: Two patient groups were studied. Cohort 1 comprised 91 patients with biopsy-proven glomerular disease who were followed-up for 5 years before categorization as either non-progressors (with stable serum creatinine or < or =30% increase over 5 years, n = 39) or progressors (requiring dialysis, transplantation or whose serum creatinine increased by >30% over 5 years, n = 52). Cohort 2 comprised 107 patients with various primary renal diseases, who had reached CKD stage 5 and undergone renal transplantation at the time of study. All patients were genotyped for the VEGF polymorphisms at positions -460 (C/T) and +405 (G/C). Linkage disequilibrium (LD) was established using EHplus. SNPHAP was used to estimate haplotype frequency and to infer haplotypes to all patients. Cohort 1 patients were genotyped for the TGF-beta1 polymorphisms at positions -800, -509, codons 10 and 25. Genotyping was performed by polymerase chain reaction-restriction length polymorphism (PCR-RFLP). RESULTS: In cohort 1, there was a significant increase in frequency of the -460 VEGF CC genotype 30.8 vs 5.1%, P = 0.008; odds ratio (OR), CC vs TT 10.67, 95% confidence interval (CI), 1.94-58.72 and C allele 56.7 vs 37.2%, P = 0.009; OR 2.22, 95% CI, 1.21-4.04, in the progressor patients when compared with the non-progressors. In cohort 2, there was a significant increase in the VEGF -460 CC genotype when compared with healthy volunteers 37 vs 20.8%, P = 0.011; OR CC vs TT 1.59, 95% CI, 0.72-3.51. The -460 and +405 polymorphisms were in LD P < 0.00007. There were significant differences in diplotype (haplotype pair) frequencies in cohort 1 and 2, P = 0.018, which confirmed the importance of the -460C allele. There were no associations between the VEGF +405 or TGF-beta1 polymorphisms and progressive renal disease. CONCLUSION: In this study, we have demonstrated an association between the VEGF -460 polymorphism and progression to CKD stage 5. The function of this polymorphism remains unclear although previous evidence suggests that promoter constructs containing this single nucleotide polymorphism (SNP) have been associated with increased activity. Clearly there is a role for TGF-beta1 in chronic kidney disease. However, this study found no associations with four TGF-beta1 polymorphisms in this cohort.     

Polymorphism of the renin-angiotensin-aldosterone system in patients with chronic allograft dysfunction

Polymorphism of the gene encoding components of the renin-angiotensin-aldosterone synthase system (RAAS) represents an area of intense research of cardiovascular disease associations. Numerous studies have addressed the role of RAAS gene polymorphisms in the development and progression of renal disease. Also, it has been reported that patient with ACE (DD) and angiotensinogen AGT (TT) genotypes are associated with chronic allograft dysfunction (CAD). We investigated the effects of gene polymorphisms of the renin-angiotensin-aldosterone system in renal transplant patients (81 males and 50 females; mean age 29.6+/-10.2 years). Genotypes were determined using polymerase chain reaction sequence specific primers and PCR followed by RFLP analysis. Renal allograft recipients with chronic allograft dysfunction had significantly higher frequencies of the MM genotype than those without CAD (P<0.05). The other genetic polymorphisms of the RAAS were not associated with CAD. This study proves that determination of AGT M235T genotype before transplantation may help identify patients who are at risk for chronic renal transplant dysfunction.     

Recipient RAS gene variants and renal allograft function

BACKGROUND: Genetic variants of the renin-angiotensin system (RAS) have been implicated in the progression of native kidney diseases. A decreased long-term renal allograft function has also been associated with increased activity of RAS, which may be genetically determined. METHODS: The effect of the angiotensinogen (AGT), angiotensin-converting enzyme (ACE), angiotensin type 1 receptor (AGT1R), and aldosterone synthase (CYP11B2) genotypes on renal function was investigated in 223 first-allograft recipients. Graft function was estimated by yearly determinations of serum creatinine. Genotyping was performed for the M235T-AGT, the I/D-ACE, the A1166C-AGT1R, and the -344T/C-CYP11B2 gene polymorphisms using polymerase chain reaction. RESULTS: The percentage of patients with preserved stable graft function up to 15 years after transplantation was higher when mean blood pressure was <97 mmHg, than when it was >117 mmHg (60 vs. 25% of patients). The CYP11B2 genotype predicted long-term stable graft function with more patients suffering from worsening renal function with the CYP11B2 TT than the CC genotype (P=0.002). There was a weak association between the AGT1R genotype (P=0.037), but not the AGT or ACE genotypes, and a preserved long-term graft function. Cox proportional hazards estimation showed no interactions between the observed effect of CYP11B2 genotype on renal function over time and the number of HLA class I and II matches, other RAS genotypes, graft function, or mean blood pressure at 1 year after transplantation. CONCLUSIONS: The rate of decline in renal allograft function is strongly associated with the CYP11B2 but not AGT, ACE, or AGT1R genotypes. This finding suggests that certain genetic factors related to the RAS are important determinants of long-term renal allograft function.     

Association of cytokine polymorphisms with subclinical progressive chronic allograft nephropathy in Japanese renal transplant recipients: Preliminary study

BACKGROUND: The present study calculated the risk of developing subclinical progressive chronic/sclerosing allograft nephropathy (CAN) under tacrolimus-based immunosuppression according to genetic polymorphisms of cytokines and growth factors, and clinical events including delayed graft function (DGF), acute rejection (AR) and cytomegalovirus (CMV) infection. METHODS: The subjects were 50 recipients with stable graft function more than one year after renal transplantation. The criteria for subclinical progressive CAN were CAN grade 2 or 3 changes on Banff classification and stable serum creatinine (SCr) levels. Ten genetic polymorphisms were assessed. RESULTS: Eleven patients (22.0%) developed progressive CAN. The mean ages and SCr levels of recipients with and without progressive CAN were 41.2 and 47.1 years, and 1.46 and 1.22 mg/dL, respectively. There were no significant differences in donor age, number of HLA mismatches, DGF or CMV infection. Although the rate of AR episode seemed to be greater in patients with subclinical progressive CAN, the difference did not reach significance (P = 0.093). The frequencies of the interleukin (IL)-2 T-330G TT genotype (P = 0.046) and IL-4 C-590T C allele (P = 0.092) were higher in patients with progressive CAN. In univariate analysis, the presence of IL-2 T-330G TT (OR 4.57, P = 0.044) was associated with CAN development. CONCLUSION: The presence of IL-2 T-330G TT genotype may be a risk factor for CAN. Further studies with a large number of subjects and analyses of many cytokine polymorphisms would contribute to the ability to make prognostic determinations or tailor immunomodulatory regimens after renal transplantation.     

肌球蛋白重链9基因单核苷酸多态性与内蒙古自治区汉族IgA肾病临床、病理及预后的关系

目的 探讨肌球蛋白重链(MYH)9基因单核苷酸多态性与内蒙古自治区汉族IgA肾病患者临床特征、病理及预后的关系.方法 以经肾组织活检确诊的IgA肾病患者148例为研究对象,对其中56例患者进行了1～97月的随访.取外周血提取DNA,采用PCR限制性片段长度多态性分析(RFLP)法检测MYH9基因Rs3752462、Rs4821480位点单核苷酸多态性.研究各位点基因型与IgA肾病患者临床特征的相关性.分析不同基因型与疾病进展和预后的关系.结果 (1)Rs3752462位点符合Hardy-Weinberg平衡,Rs4821480位点不符合Hardy-Weinberg平衡.(2)IgA肾病患者MYH9基因Rs3752462位点TT基因型患者的收缩压低于CC+CT基因型(P＜0.05).Rs4821480位点GG基因型与TT+GT基因型两组患者收缩压、舒张压、年龄差异有统计学意义(P＜0.05).Scr、肌酐清除率、血白蛋白、血红蛋白、镜下血尿、蛋白尿程度等临床指标及病理HASS分级、肾病理改变在Rs4821480位点、Rs3752462位点3种基因型组间差异无统计学意义.(3) Kaplan-Meier生存分析提示Rs3752462位点CC基因型、Rs4821480位点TT基因型患者肾活检到肾功能减退时间显著较短(P＜0.05).结论 MYH9基因Rs3752462位点C等位基因是引起IgA肾病患者高血压损害的独立危险因素.MYH9基因Rs4821480位点3种基因型多态性与患者预后相关.携带Rs3752462位点C等位基因、Rs4821480位点T等位基因可能影响患者的预后.