2型糖尿病肾病患者p22phox基因多态性的研究

目的研究NADPH氧化酶p22phox亚基基因多态性与中国上海汉族人群2型糖尿病肾病（DN）相关性。方法应用限制性片断长度多态性（RFLP）-PCR方法对105例健康对照组和194例2型糖尿病（DM）患者（其中71例DN）进行p22phox亚基C242T、A640G基因型检测。同时检测其身高、体重、血压、血脂、空腹血糖及胰岛素、HbAlc的水平。结果DN组CT＋TT基因型频率明显高于2型DM和对照组（26．76％比17．07％、3．81％，P=0．0002）；DN组T等位基因频率明显高于2型DM和对照组（22．54％比13．42％、2．86％，P=0．0001）；3组间AA基因型频率与A等位基因频率差异无统计学意义。多元回归分析显示，T242等位基因、收缩压、空腹血糖、HbAlc、β细胞功能指数（Homa-IS）是DN的危险因素。结论p22phox亚基T242等位基因变异可能是中国上海地区汉族人群DN的易感基因：而p22phox亚基A640G基因多态性与上述人群DN无相关性。T242等位基因、收缩压、空腹血糖、HbAlc、Homa-IS是DN的危险因素。     

Role of alpha-adducin DNA polymorphisms in the genetic predisposition to diabetic nephropathy.

BACKGROUND: There is substantial evidence for genetic susceptibility to diabetic nephropathy. In particular, genes that predispose to hypertension in the general population may confer susceptibility to nephropathy in patients with diabetes. A Gly460Trp variant in the alpha-adducin gene has been associated with essential hypertension. Our aim was to screen the alpha-adducin gene for polymorphisms and to determine if any variants predisposed patients with diabetes to nephropathy. A secondary objective was to assess for association between the Gly460Trp variant and hypertension. METHODS: The exons of the alpha-adducin gene were resequenced in 30 individuals. Selected variants were then genotyped in 155 patients with type 1 diabetes and nephropathy (cases) and 216 persons with type 1 diabetes but no evidence of nephropathy (controls) from Northern Ireland and in 95 cases and 118 controls from the Irish Republic. RESULTS: Eleven polymorphisms were detected, of which six were novel and three caused amino-acid substitutions. The Gly460Trp and a novel Ser617Cys polymorphism were in strong linkage disequilibrium (D' = 0.98). Neither the genotype nor allele frequencies for the Gly460Trp polymorphism (P = 0.89 and 0.93 respectively) or the Ser617Cys polymorphism (P = 0.46 and 0.76) were significantly different between cases and controls when the Northern Ireland and Irish Republic sample groups were combined. Carriage of the 460Trp allele was not significantly associated with systolic or diastolic blood pressure in either the cases (P = 0.48 and 0.06, respectively) or in the controls (P = 0.50 and 0.94, respectively). CONCLUSIONS: Variation in the alpha-adducin gene does not play a major role in the development of nephropathy in persons with type 1 diabetes in the Irish population. Furthermore, the Gly460Trp variant was not associated with hypertension in this population.     

The human peroxisome proliferator-activated receptor gamma2 (PPARgamma2) Pro12Ala polymorphism is associated with decreased risk of diabetic nephropathy in patients with type 2 diabetes

The peroxisome proliferator-activated receptor gamma2 (PPARgamma2) Pro12Ala polymorphism has been associated with a decreased risk of type 2 diabetes and a lower albumin excretion rate (AER) in patients with established diabetes. We performed a case-control study aiming to evaluate the association between the Pro12Ala polymorphism and diabetic nephropathy. Genomic DNA was obtained from 104 type 2 diabetic patients (case subjects) with chronic renal insufficiency (78 on dialysis and 26 with proteinuria [AER >or=200 microg/min] and serum creatinine >or=2.0 mg/dl) and 212 normoalbuminuric patients (AER <20 microg/min) with known diabetes duration >or=10 years (control subjects). The genotypic distribution of the PPARgamma2 Pro12Ala polymorphism in these diabetic patients was in Hardy-Weinberg equilibrium, and the Ala allele frequency was 9%. The frequency of Ala carriers (Ala/Ala or Ala/Pro) was 20.3% in control subjects and 10.6% in case subjects (P = 0.031). The odds ratio of having diabetic nephropathy for Ala carriers was 0.465 (95% CI 0.229-0.945; P = 0.034). Carriers of the Ala allele were not different from noncarriers (Pro/Pro) regarding sex (38.9 vs. 44.1% males) or ethnicity (77.4 vs. 71.7% white) distribution, age (61 +/- 10 vs. 61 +/- 10 years), known diabetes duration (17 +/- 7 vs. 16 +/- 7 years), BMI (27 +/- 4 vs. 28 +/- 5 kg/m(2)), fasting plasma glucose (184 +/- 81 vs. 176 +/- 72 mg/dl), HbA(1c) (6.7 +/- 2.3 vs. 6.9 +/- 2.4%; high-performance liquid chromatography reference range: 2.7-4.3%), and systolic (145 +/- 27 vs. 0.144 +/- 24 mmHg) or diastolic (87 +/- 14 vs. 85 +/- 14 mmHg) blood pressure, respectively. In conclusion, the presence of the Ala allele may confer protection from diabetic nephropathy in patients with type 2 diabetes.     

Association between high von willebrand factor levels and the Thr789Ala vWF gene polymorphism but not with nephropathy in type I diabetes. The GENEDIAB Study Group and the DESIR Study Group

BACKGROUND: A genetic susceptibility for diabetic kidney disease is suspected since diabetic nephropathy occurs in only 30 to 40% of type I diabetic patients. As elevated von Willebrand factor (vWF) plasma concentrations have been reported to precede the development of microalbuminuria in type I diabetes, we addressed a possible implication of vWF as a genetic determinant for diabetic nephropathy. METHODS: Three known vWF gene polymorphisms were genotyped in a group of 493 type I diabetic subjects, all showing proliferative retinopathy, but with various stages of renal involvement, which ranged from no microalbuminuria, despite a mean duration of diabetes of 31 years, to advanced nephropathy (GENEDIAB Study): Thr789Ala (Rsa I), M-/M+ (Msp I) (intron 19), and Ala1381Thr (Hph I). Plasma vWF and factor VIII (F VIII) levels were also measured in this population. RESULTS: Plasma vWF and F VIII levels were increased in diabetic subjects with nephropathy (P < 0.001) or with coronary heart disease (CHD; P < 0.001), but there was no interaction of both conditions on plasma levels. The Msp I polymorphism (M-/M+) was weakly associated with nephropathy (P = 0. 04), but this association was not more significant when other risk factors were used in a logistic regression analysis. The vWF Thr789Ala polymorphism was associated with CHD (P = 0.002) and with plasma vWF levels. Logistic regression analysis indicated an independent and codominant effect of the Thr789Ala polymorphism on CHD, but not on nephropathy, with a maximal risk for Ala/Ala homozygotes (OR = 4.2, 95% CI, 1.8 to 9.9, P = 0.0008). CONCLUSION: It is unlikely that polymorphisms in the vWF gene contribute to the risk for nephropathy in type I diabetic patients. However, the Thr789Ala polymorphism might affect the risk for CHD in this population through modulation of plasma vWF levels.     

Association of solute carrier family 12 (sodium/chloride) member 3 with diabetic nephropathy, identified by genome-wide analyses of single nucleotide polymorphisms

To identify genetic elements that might confer susceptibility to diabetic nephropathy, we performed a genome-wide analysis of gene-based single nucleotide polymorphisms (SNPs) in a large cohort of Japanese patients with diabetes. In case-control association studies, patients with type 2 diabetes were divided into two groups, one having retinopathy as well as overt nephropathy and the other (the control group) having diabetic retinopathy but with no signs of renal involvement. Genotyping of these patients at >55,000 SNP loci indicated a gene encoding solute carrier family 12 member 3 (SLC12A3) to be a good candidate for the susceptibility to diabetic nephropathy, in view of a significant association of one landmark SNP located in the 24th intron (chi(2) = 15.4, P = 0.000087, odds ratio = 2.53 [95% CI 1.57-4.09]). Subsequent analysis of additional genetic variations in this gene identified several SNPs that were significantly associated with nephropathy, especially one in exon 23 (+78 G to A: Arg913Gln, chi(2) = 18.5, P = 0.00002, odds ratio = 2.53 [95% CI 1.64-3.90]). The results implicated that substitution of Arg913 to Gln in the SLC12A3 gene might reduce the risk to develop diabetic nephropathy and suggested that the gene product might be a potential target for the prevention or treatment of this disease.     

A family-based association study of megsin A23167G polymorphism with susceptibility and progression of IgA nephropathy in a Chinese population

AIMS: To investigate the association of megsin A23167G polymorphism with susceptibility and progression of IgA nephropathy in Chinese population. METHODS: 435 IgA nephropathy patients and their family members were recruited for a family-based association study. Genotypes of megsin A23167G were determined by direct sequencing. The results were analyzed by transmission disequilibrium test (TDT) and haplotype relative risk (HRR). Clinical data and histological scores of renal lesions were compared between patients with different genotypes. According to disease stability, IgA nephropathy patients were divided into progressive group and stable group. The distribution of genotype frequencies were compared between the 2 groups. RESULTS: TDT revealed that megsin 23167G alleles were transmitted more frequently from heterozygous parents to patients than expected (classical TDT: chi2 = 5.435, p = 0.020, extended TDT: chi2 = 5.017, p = 0.025). HRR analyses showed significant differences between transmitted and nontransmitted allele frequencies (chi2 = 7.006, p = 0.008, HRR = 1.762). The scores of glomerular index and glomerular sclerosis index were higher in GG genotype patients than those in other genotypes (F = 4.570, p = 0.033, F = 4.324, p = 0.038, respectively). The distribution frequency of GG genotype in the progressive group was higher than that of the stable group (chi2 = 4.370, p = 0.037). No statistical difference was found in tubulo-interstitial index, vascular index and clinical characteristics between the 2 groups. CONCLUSION: The polymorphism of megsin A23167G is associated with susceptibility and progression of IgA nephropathy in Chinese population. GG genotype is associated with severe histological lesions and progression of the disease.     

Association of plasminogen activator inhibitor-1 4G/4G genotype and type 2 diabetic nephropathy in Chinese patients

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) is a key regulator of fibrinolytic pathway and extracellular matrix (ECM) turnover. Because diabetic nephropathy is characterized by the presence of basement membrane thickening and mesangial expansion, we examined the role of PAI-1 gene polymorphisms in the development of type 2 diabetic nephropathy. Evidence also suggested that the PA/plasmin system and the renin-angiotensin system (RAS) interact together to affect the risk of fibrosis and thrombosis. Hence, we also studied the synergistic effect between PAI-1 and angiotensin-converting enzyme (ACE) gene polymorphisms. METHODS: The PAI-1 and ACE (D/I) gene polymorphisms were examined in a cohort of Chinese type 2 diabetic patients who had diabetes for an average of 14 years. These patients were sex and age matched. Group A (N = 46) consisted of patients without diabetic nephropathy (normoalbuminuric with creatinine <120 micromol/L), and group B (N = 95) was with diabetic nephropathy (with albuminuria or renal impairment, including patients on dialysis). RESULTS: Patients with type 2 diabetic nephropathy had a higher frequency of PAI-1 (4G/4G) genotypes than those without nephropathy [4G/4G:4G/5G:5G/5G = 41:38:21 (%) vs. 15:65:20(%), P = 0.005]. Diabetic patients with coexistence of PAI-1 4G/4G genotype and ACE D alleles had a higher incidence of diabetic nephropathy (22 vs. 7%, P = 0.012) than those with other combinations of genotypes. Multivariate logistic regression analysis showed that PAI-1 4G/4G (P = 0.01) and the prevalence of hypertension (P < 0.0001) are independent risk factors of development of type 2 diabetic nephropathy. CONCLUSIONS: These results suggest that the PAI-1 4G/4G genotype is associated with an increased risk for type 2 diabetic nephropathy in Chinese patients, which is an independent risk factor for the development of nephropathy. The PAI-1 4G/4G genotype also exhibits a synergistic effect with the ACE D allele on development of diabetic nephropathy.     

过氧化物酶体增殖物激活受体-γ及其共激活蛋白1的单核苷酸多态性与多囊卵巢综合征表型的关系

目的研究过氧化物酶体增殖物激活受体-γ2(PPAR-γ2)和过氧化物酶体增殖物激活受体-γ共激活蛋白1(PGC-1)α的单核苷酸多态性与多囊卵巢综合征(PCOS)发病及生殖激素的关系。方法收集PCOS患者和非PCOS妇女正常对照的血液标本。记录两组的初潮年龄,身高、体重,分离血清测定生殖激素,分离血液中的淋巴细胞提取总DNA,特异引物扩增后限制性酶切(PCR-RFLP),电泳分离,溴化乙锭(EB)染色。结果PCOS患者的PPAR-γ2(Pro12Pro,Pro12Ala和Ala12Ala)基因型分布(分别为0.910,0.090,0)与正常人的分布(分别为0.925,0.068,0.007)无显著差异。PCOS患者的PGC-1α(Gly482Gly,Gly482Ser和Ser482Ser)基因型分布(分别为0.328,0.402,0.269)与正常人的分布(分别为0.333,0.374,0.293)无显著差异。体重指数(BMI)、血清总睾酮(T)和卵泡刺激素(FSH)、黄体生成素(LH)、LH/FSH、孕酮(P)和雌二醇(E2)在PPAR-γ2和PGC-1α各基因型之间无显著差异。与其他人种比较,中国人PPAR-γ2中Ala等位基因频率较低(4.4%),但PGC-1α的频率较高(48%)。结论结果提示PPARγ2 Pro12Ala和PGC-1αGly482Ser这两种单核苷酸多态性与PCOS的发病无相关性。     

Susceptibility to Paget's disease of bone is influenced by a common polymorphic variant of osteoprotegerin.

To clarify the role of the TNFRSF11B gene encoding osteoprotegerin (OPG), in Paget's disease of bone (PDB) we studied TNFRSF11B polymorphisms in an association study of 690 UK subjects and in a worldwide familial study of 66 kindreds. We found that the G1181 allele of TNFRSF11B, encoding lysine at codon 3 of the OPG protein, predisposes to both sporadic and familial PDB. INTRODUCTION: Paget's disease of bone (PDB) is a common disorder characterized by focal abnormalities of bone turnover. Genetic factors are important in the pathogenesis of PDB, and studies have shown that inactivating mutations of the TNFRSF11B gene, encoding osteoprotegerin (OPG), cause the rare syndrome of juvenile Paget's disease. In this study, we sought to determine whether polymorphisms of the TNFRSF11B gene contribute to the pathogenesis of classical PDB. MATERIALS AND METHODS: We screened for polymorphisms of the TNFRSF11B gene by DNA sequencing of the proximal promoter, coding exons, and intron-exon boundaries in 20 PDB patients and 10 controls. Informative single nucleotide polymorphisms (SNPs), including a G1181C SNP, which predicts a lysine-asparagine substitution at codon 3 of the OPG signal peptide and haplotypes, were related to the presence of PDB in 312 cases compared with 378 controls and to transmission of PDB in 140 affected offspring from 66 kindreds with familial PDB. RESULTS AND CONCLUSIONS: The G1181 allele was significantly over-represented in PDB patients (chi(2) = 5.7, df = 1, p = 0.017, adjusted alpha = 0.024), equivalent to an odds ratio for PDB of 1.55 (95% CI: 1.11-2.16). The distribution of TNFRSF11B haplotypes significantly differed in sporadic PDB cases and controls (chi(2) = 30.2, df = 9, p < 0.001) because of over-representation of haplotypes containing the G1181 allele in cases. The family study showed that the most common haplotype containing the G1181 allele was transmitted more frequently than expected to 140 individuals with familial PDB (chi(2) = 7.35, df = 1, p < 0.01), and the transmission disequilibrium was even more pronounced in a subgroup of 78 familial PDB patients who did not carry mutations of the SQSTM1 gene (chi(2) = 8.44, df = 1, p < 0.005). We conclude that the G1181 allele of TNFRSF11B, encoding lysine at codon 3 of the OPG protein, predisposes to the development of sporadic PDB and familial PDB that is not caused by SQSTM1 mutations.     

Synergistical action of the β2 adrenoceptor and fatty acid binding protein 2 polymorphisms on the loss of glomerular filtration rate in Chinese patients with type 2 diabetic nephropathy

Purpose

Since altered sympathetic nerve activity and insulin resistance are implicated in the pathogenesis of type 2 diabetic nephropathy, we investigated the effect of polymorphic Arg16Gly and Gln27Glu in the β2 adrenoceptor gene and Ala54Thr in the fatty acid binding protein 2 gene on the estimated glomerular filtration rate (eGFR) in Chinese patients with the above disease.

Methods

A total of 552 diabetic subjects recruited from annual health examinations were studied. The eGFR was calculated from the Modification of Diet in Renal Disease equation for the Chinese. Plasma norepinephrine level and genotype were determined by high-performance liquid chromatography–tandem mass spectrometry and TaqMan method, respectively. Holter-derived heart rate viability (HRV) and the MRI-generated renal apparent diffusion coefficient (ADC) were evaluated.

Results

The Gly16Gly and Thr54Thr homozygotes had significantly higher microalbuminuria and lower eGFR against other genotypes in their individual polymorphism. Besides, the Gly16Gly variant exhibited markedly elevated norepinephrine level, whereas indicative of insulin resistance was increased in the Thr54Thr one. Multiple linear regression analysis further confirmed the independent genetic effect on the eGFR. Moreover, multifactor dimensionality reduction method detected a gene–gene synergistic action that subjects with the Gly16Gly/Thr54Thr genotype were exposed to higher risk of eGFR loss. Finally, these findings were accompanied by lower HRV and ADC, indicating sympathetically mediated hemodynamic changes.

Conclusions

By uncovering the genetic component of the coherent interplay between the elevated sympathetic nerve activity and metabolic disorders, our observations might promote the development of novel personalized prevention and management strategies against the diabetic nephropathy, especially in the genetically susceptible individuals.

     

Risk of diabetic nephropathy in type 1 diabetes is associated with functional polymorphisms in RANTES receptor gene (CCR5): a sex-specific effect

Chemokines and their receptors have been implicated in the development of diabetic nephropathy. To determine whether the risk of diabetic nephropathy is influenced by two functional polymorphisms in the regulated upon activation normal T-cell expressed and secreted (RANTES) receptor gene (CCR5), we recruited patients with type 1 diabetes, including 496 case subjects with overt proteinuria or end-stage renal disease and 298 control subjects with normoalbuminuria. Male carriers of the 59029G allele, which is associated with diminished expression of CCR5 on the surface of immunocompetent cells, had significantly higher risk of developing diabetic nephropathy than noncarriers (OR [95% CI] 1.9 [1.2-3.0]). Similarly, male carriers of the 32-bp deletion, which causes truncation of the protein, had significantly higher risk of diabetic nephropathy than noncarriers (2.3 [1.3-4.2]). Combining both polymorphisms, three haplotypes were distinguished: one nonrisk haplotype carrying the 59029A allele and the 32-bp insertion and two risk haplotypes carrying the 59029A allele with the 32-bp deletion and carrying the 59029G allele with the 32-bp insertion. The distribution of these haplotypes differed significantly (P < 0.00001) in men with and without diabetic nephropathy but was not associated with diabetic nephropathy in women. In conclusion, two functional polymorphisms in CCR5 that decrease expression of the RANTES receptor on immunocompetent cells are associated with increased risk of diabetic nephropathy in type 1 diabetes, but only in men.     

Pregnancy in Patients with Diabetic Nephropathy

Background and Aim  To determine the influence of pregnancy on renal functions in patients with diabetic nephropathy and influence of diabetic nephropathy on pregnancy outcome. Methods  A prospective cohort study was carried out on 15 patients with diabetic nephropathy with pregnancy (group 1), 15 diabetic patients with diabetic nephropathy without pregnancy (group 2) and 15 pregnant diabetic patients without nephropathy (group 3). Patients with diabetic nephropathy with serum creatinine less than 3 mg% were involved. Renal function tests were done every 3 months for 18 months. Pregnancy outcome and complications were recorded. Results  Comparing group 1 and group 2 shows significant difference as regards percent increase in serum creatinine, percent change in GFR and percent increase in urinary proteins. Comparing group 1 and group 3 shows significant difference as regards rate of toxemia of pregnancy, preterm delivery and small for age babies. Mean blood pressure, GFR deterioration and mean HbA1c are the main determinant of most complications. Conclusions  Pregnancy leads to deterioration in renal functions in patients with diabetic nephropathy with elevated serum creatinine; also the presence of diabetic nephropathy increases pregnancy unfavorable outcomes. Special care should be given to blood pressure control, blood sugar control and control of renal condition.     

Lack of relationship in long-term type 1 diabetic patients between diabetic nephropathy and polymorphisms in apolipoprotein epsilon, lipoprotein lipase and cholesteryl ester transfer protein. Genétique de la Nephropathie Diabétique Study Group. Données Epidémiologiques sur le Syndrome d'Insulino-Résistance Study Group.

BACKGROUND: Genetic susceptibility contributes to the risk of diabetic nephropathy. Lipid disorders may favour diabetic nephropathy. Thus polymorphisms in lipid metabolism are candidates for the genetic component of risk for diabetic nephropathy. METHODS: We searched for a contribution of the genetic polymorphisms of lipoprotein lipase (LPL), cholesteryl ester transfer protein (CETP) and apolipoprotein epsilon (Apo E) to the development of diabetic nephropathy by studying 494 type 1 diabetic patients with proliferative retinopathy and various stages of diabetic nephropathy (GENEDIAB Study). The selection process ensured that all patients had expressed their risk of chronic complications due to uncontrolled diabetes. Thus the nephropathy stages were largely influenced by genetic background. The lipid profile included fasting plasma total cholesterol (TC), triglycerides (TG), apolipoprotein A1 (Apo A1) and B (Apo B), and lipoprotein (a) (Lp(a)). Genetic polymorphisms were determined by PCR-based detection of Apo epsilon (e2/e3/e4), LPL (mutation Asn 291 Ser) and CETP (TAQ:IB B1/B2). RESULTS: One hundred and fifty-seven patients (32%) had no nephropathy, 104 (21%) incipient nephropathy, 126 (25%) established nephropathy and 107 (22%) advanced nephropathy. There was a significant relationship between the stages of diabetic nephropathy and TC (P=0.002), TG (P<0.0001), Apo B (P=0.0007) or Lp(a) (P=0. 038), but not Apo A1. However the genetic polymorphism distributions of LPL, CETP and Apo epsilon did not differ in terms of renal complications. The study power to reject the null hypothesis was 58% for the Apo epsilon genotypes. CONCLUSION: These results support no or only marginal effects of a genetic basis for lipid disturbances encountered in diabetic nephropathy.     

Angiotensin receptor blockers in diabetic nephropathy: renal and cardiovascular end points

The activity of the renin-angiotensin-aldosterone system (RAAS) is elevated both in the circulation and in the renal tissue of diabetic and nondiabetic nephropathies. The increased RAAS activity plays an important role in the hemodynamic and nonhemodynamic pathogenetic mechanisms involved in kidney disease. Previous studies have demonstrated that albuminuria is not only a marker of glomerular lesions, but also a progression promoter, and finally a powerful predictor of the long-term beneficial effect of blood pressure-lowering therapy. Randomized crossover and parallel blind studies in patients with diabetic nephropathy have demonstrated that angiotensin II receptor blockers (ARB) induce favorable changes in systemic blood pressure, renal hemodynamics, and proteinuria similar to those induced by angiotensin-converting enzyme (ACE) inhibition. Studies have revealed the optimal renoprotective dose for some ARBs; however, additional dose titration studies are urgently needed to obtain the maximum benefit of this valuable new class of compounds. The combination of ARB and ACE inhibition is well tolerated and even more effective than monotherapy in reducing systemic blood pressure and albuminuria in diabetic nephropathy. In addition, dual RAAS blockade is safe and well tolerated. Impaired autoregulation of glomerular filtration rate (GFR); demonstrated with some blood pressure-lowering agents implies disturbances in the downstream transmission of the systemic blood pressure into the glomerulus, leading to capillary hypertension or hypotension depending of the level of blood pressure. ARB does not interfere with GFR autoregulation in hypertensive diabetic patients. In contrast to previous observational studies with ACE inhibition, long-term treatment with ARB has similar beneficial renoprotective effect on progression of diabetic kidney disease in hypertensive diabetic patients with ACE II and DD genotypes. ARB can prevent/delay development of diabetic nephropathy independently of its beneficial blood pressure-lowering effect in patients with type 2 diabetes and microalbuminuria. Recently, two landmark studies led to the following conclusion: "Losartan and Irbesartan conferred significant renal benefit in patients with type 2 diabetes and nephropathy. This protection is independent of the reduction in blood pressure it causes. The ARB is generally safe and well tolerated." A recent metaanalysis indicates that ARBs reduce cardiovascular events mainly because of reduction in first hospitalization for congestive heart failure in hypertensive type 2 diabetic patients with albuminuria. The studies mentioned here suggest that ARB represents a beneficial treatment of hypertension and proteinuria in incipient and overt diabetic nephropathy.     

Peroxisome proliferator-activated receptor-gamma2 polymorphism Pro12Ala is associated with nephropathy in type 2 diabetes: The Berlin Diabetes Mellitus (BeDiaM) Study

The Pro12Ala polymorphism of the gene encoding the peroxisome proliferator-activated receptor (PPAR)-gamma2 has recently been shown to be associated with type 2 diabetes. In the present analysis, we investigated whether PPAR-gamma2 Pro12Ala was associated with microvascular complications of type 2 diabetes, such as albuminuria, end-stage renal failure (ESRF), or retinopathy. A total of 445 patients with type 2 diabetes who were enrolled in the Berlin Diabetes Mellitus Study and in whom we determined albuminuria and the presence of ESRF and retinopathy were genotyped for the PPAR-gamma2 Pro12Ala polymorphism. We also measured potentially important covariables, such as blood pressure, BMI, duration of diabetes, glycosylated hemoglobin, serum creatinine, and serum lipids. Among 445 patients with type 2 diabetes (mean age 59.3 years), the Pro12Ala genotype distribution was in Hardy-Weinberg equilibrium (P = 0.42). The Ala12 allele frequency was 0.14. With adjustment for covariables, the 118 Ala12 allele carriers had significantly lower urinary albumin excretion (UAE) than the 327 noncarriers (17.1 vs. 25.8 mg/d; P = 0.01). The percentage decrease in UAE observed in PPAR-gamma Ala12 allele carriers relative to noncarriers (P = 0.003) rose from 0.2% (P = 0.99) to 54% (P = 0.008) and to 70% (P = 0.01) when the duration of diabetes increased from <10 years to 10-19 years and to >or=20 years, respectively. Similarly, the odds ratios of having albuminuria decreased from 1.22 (P = 0.54) to 0.61 (P = 0.23) and to 0.11 (P = 0.007), respectively. Among patients with type 2 diabetes, PPAR-gamma2 Ala12 allele carriers had significantly lower UAE and tended to develop overt proteinuria less frequently. These observations suggest a protective effect of the Ala12 allele in relation to diabetic nephropathy.     

Endothelial nitric oxide synthase gene polymorphism in intron 4 affects the progression of renal failure in non-diabetic renal diseases.

BACKGROUND: Nitric oxide is a very potent regulator of intrarenal haemodynamics and is thought to be an important factor in the deterioration of renal function. Our study sought to verify the hypothesis that endothelial nitric oxide synthase (ecNOS) gene polymorphism in intron 4 might have some relevance to progression in chronic renal failure. METHODS: We studied the frequencies of gene polymorphism of ecNOS intron 4 in patients with end-stage renal disease (302 cases) and compared it with that of healthy subjects (248 cases). ecNOS genotypes were determined by the polymerase chain reaction, followed by agarose gel electrophoresis. RESULTS: Two alleles of ecNOS intron 4, labelled a and b could be detected; a has four and b has five tandem 27-bp repeats. The frequencies of ecNOS4b/b, ecNOS4b/a, ecNOS4a/a genotypes were 81.0% (201/248), 19. 0% (47/248), 0.0% (0/248) in the control group, and 74.8% (226/302), 23.5% (71/302), l.7% (5/302) in all the patients, 72.7% (168/231), 25.1% (58/231), 2.2% (5/231) in the group with end-stage renal diseases, excluding diabetic nephropathy (non-DM group), and 81.7% (58/71), 18.3% (13/71), 0.0% (0/71) in diabetic nephropathy (DM group) respectively. The frequency of the ecNOS4a (ecNOSb/a, and ecNOSa/a) in all the patients and in the non-DM group were significantly higher than that in the control group (P=0.021; P=0. 0096 respectively). In contrast, there was no significant difference in the frequencies of ecNOS genotypes between the DM group and the control group (P=0.81). CONCLUSION: Among the frequencies of ecNOS intron 4 gene polymorphism, a allele displayed a significantly higher frequency in cases with end-stage renal failure (ESRF) not caused by diabetic nephropathy. ecNOS gene polymorphism in intron 4 appears, therefore, to affect the progression of renal failure in non- diabetic renal diseases, but the same conclusion could not be drawn in diabetic nephropathy.     

Frequency and effects of apolipoprotein E polymorphism in Mexican-American NIDDM subjects

We typed 254 non-insulin-dependent diabetic (NIDDM) Mexican Americans living in Starr County, Texas, for the three common apolipoprotein E (apoE) alleles. Typing was performed via DNA amplification and Hha I restriction. The allele frequencies (epsilon 2 = 0.041, epsilon 3 = 0.860, epsilon 4 = 0.099) were in Hardy-Weinberg equilibrium (chi 2 = 0.60, df = 3) and did not differ from a random sample from the same population (chi 2 = 0.16, df = 2). Analysis of variance was used to test for mean differences in lipid, lipoprotein, and glucose levels among apoE types. Significant differences among types were detected for low-density lipoprotein cholesterol (LDL-chol; P = 0.042, R2 = 2.6) and beta-lipoprotein cholesterol (P = 0.019, R2 = 3.3) levels. Mean LDL-chol in E2/3 individuals was 2.69 mM, E3/3 was 3.26 mM, and E4/3 was 3.36 mM. Mean beta-lipoprotein cholesterol in E2/3 individuals was 3.05 mM, E3/3 was 3.64 mM, and E4/3 was 3.67 mM. Based on these results, we conclude that the effects of the apoE polymorphism on lipid profiles and glucose levels are the same in NIDDM subjects as in nondiabetic Mexican Americans and other populations. Other studies investigating the role of apoE polymorphism in diabetic subjects have found increased triglyceride levels in individuals possessing an epsilon 2-allele and an increased frequency of the epsilon 2-allele in hyperlipidemic diabetic subjects. We found no significant difference in mean triglyceride levels among genotypes. Possible reasons for this discrepancy are discussed, including DNA- versus protein-typing methods.     

The AT2 gene may have a gender-specific effect on kidney function and pulse pressure in type I diabetic patients

Diabetic nephropathy shows a higher incidence in male subjects, which may in part be owing to genetic factors. The angiotensin II type 2 receptor (AT2), present in the renal glomerulus, may oppose the deleterious effects of the type I receptor (AT1) through vasodilatation and growth inhibition. We determined whether the functional intronic G1675A or A1818T polymorphism of the X-chromosomal AT2 gene is associated with blood pressure levels or with kidney function. We genotyped 996 (538 female/458 male subjects) Finnish patients with type I diabetes from the FinnDiane-study in a cross-sectional study. DNA samples were amplified using standard polymerase chain reaction protocol and the genotypes were determined by the minisequencing method. Male patients with the AA haplotype had a lower glomerular filtration rate (83 +/- 32 vs 94 +/- 34 ml min(-1) 1.73 m(-2), P = 0.008) and a higher pulse pressure (PP) (62 +/- 18 vs 57 +/- 15 mm Hg, P = 0.002; P < 0.05 after adjustment for age) than did those with the GT haplotype. No differences between the genotypes or haplotypes and these variables were evident in females. In males, the G1675A was also an independent variable in a linear regression analysis with PP (r(2) = 0.16, coefficient=3.64, s.e.m.=1.38, P < 0.01) as the dependent variable. These data suggest a gender-specific association between the AT2 gene and kidney function and premature aging of the arterial tree in patients with type I diabetes.     

Captopril acutely lowers albuminuria in normotensive patients with diabetic nephropathy.

Angiotensin-converting enzyme (ACE) inhibitors decrease albuminuria in patients with diabetic nephropathy. To study the change in albuminuria in relation to changes in systemic and renal hemodynamics, nine normotensive patients with type 1 (insulin-dependent) diabetes mellitus and persistent proteinuria were given a single oral dose of 25 mg of the ACE inhibitor captopril. Blood pressure, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and albumin excretion rate (AER) were measured in two periods of 40 minutes before and in four periods of 40 minutes after administration of captopril. A constant water diuresis was maintained. Blood pressure did not decrease significantly (130/79 +/- 4/3 v 124/74 +/- 4/3 mm Hg; mean +/- SEM), median AER decreased from 403 (interquartile range [IQR], 812) micrograms/min to 333 (707) micrograms/min (P < 0.01). GFR did not change (123 +/- 13 v 117 +/- 14 mL/min), but ERPF increased significantly from 609 +/- 56 to 714 +/- 55 mL/min (P < 0.01). Consequently, the filtration fraction (FF; quotient of GFR and ERPF) decreased from 0.20 +/- 0.014 to 0.17 +/- 0.014 (P < 0.01). A strong correlation was found between the decrease of AER and the decrease of FF (rs = 0.75; P < 0.02). No correlation was found between the decrease in AER and changes in GFR or blood pressure. In the normotensive patient with diabetic nephropathy, captopril causes an acute reduction of AER, which is probably mediated by a lowering of the intraglomerular pressure.     

Polymorphisms in the nephrin gene and diabetic nephropathy in type 1 diabetic patients

BACKGROUND: Several mutations in the nephrin gene are responsible for the lack of slit membrane of the glomeruli leading to massive proteinuria present already in utero. Variations in the nephrin gene may also affect the degree of proteinuria in acquired kidney diseases. We tested the hypothesis of whether any of the polymorphisms identified in the coding region of the nephrin gene were associated with diabetic nephropathy. METHODS: In a case-control, cross-sectional study, 996 Finnish type 1 diabetic patients from the FinnDiane Study were genotyped by standard polymerase chain reaction protocol. RESULTS: The frequencies of the rare alleles in the E117K, R408Q, and N1077S polymorphisms in the entire cohort were 34%, 8%, and 12%, respectively. When comparing patients with a mutant allele with the wild genotype there was no difference between the patients with end-stage renal disease, proteinuria, microalbuminuria, and those with a normal albumin excretion rate (df =3, chi2 =1.62, 1.31 and 0.77). Neither were the polymorphisms associated with the progression of kidney disease, nor with creatinine clearance and albumin excretion rate. CONCLUSION: This study does not support an involvement of the coding region of the nephrin gene in the pathogenesis of diabetic nephropathy in type 1 diabetic patients.