Variation in the resistin gene is associated with obesity and insulin-related phenotypes in Finnish subjects

Aims/hypothesis Resistin is a peptide hormone produced by adipocytes that is present at high levels in sera of obese mice and may be involved in glucose homeostasis through regulation of insulin sensitivity. Several studies in humans have found associations between polymorphisms in the resistin gene and obesity, insulin sensitivity and blood pressure. An association between variation in the resistin gene and Type 2 diabetes has been reported in some, but not all studies. The aim of this study was to analyse variants of the resistin gene for association with Type 2 diabetes and related traits in a Finnish sample.Methods In 781 cases with Type 2 diabetes, 187 spouse controls and 222 elderly controls of Finnish origin, we genotyped four previously identified non-coding single-nucleotide polymorphisms (SNPs): -420C>G from the promoter region, +156C>T and +298G>A from intron 2, and +1084G>A from the 3 untranslated region. We then tested whether these SNPs were associated with Type 2 diabetes and related traits.Results The SNPs were not significantly associated with Type 2 diabetes. However, SNPs –420C>G, +156C>T and +298G>A and the common haplotype for these three markers were associated with increased values of weight-related traits and diastolic blood pressure in cases, lower weight in elderly control subjects, and lower insulin sensitivity and greater acute insulin response in spouses. Furthermore, the +1084G allele was associated with lower HDL cholesterol in both cases and controls, higher systolic blood pressure and waist circumference in cases, and greater acute insulin response in spouse controls.Conclusions/interpretation Our results add to growing evidence that resistin is associated with variation in weight, fat distribution and insulin resistance.Electronic Supplementary Material Supplementary material is available in the online version of this article at     

Increased levels of mannan-binding lectin in type 1 diabetic patients with incipient and overt nephropathy

Aims/hypothesis Diabetic nephropathy is associated with insulin resistance, and low-grade inflammation and activation of the complement system may contribute to this cascade. Mannan-binding lectin (MBL) activates the complement system, and elevated MBL concentrations have been observed in normoalbuminuric type 1 diabetic patients. The aim of this study was to assess whether MBL is associated with diabetic nephropathy in type 1 diabetes, and whether there is an association between MBL and low-grade inflammatory markers or insulin resistance.Methods A total of 191 type 1 diabetic patients from the Finnish Diabetic Nephropathy Study were divided into three groups based upon their AER. Patients with normal AER (n=67) did not take antihypertensive medication, while patients with microalbuminuria (n=62) or macroalbuminuria (n=62) were all treated with an ACE inhibitor. As a measure of insulin sensitivity we used estimated glucose disposal rate. MBL was measured by an immunofluorometric assay, C-reactive protein by a radioimmunoassay and IL-6 by high-sensitivity enzyme immunoassay.Results Patients with normal AER (median [interquartile range]: 1,154 g/l [180–2,202 g/l]) had lower levels of MBL than patients with microalbuminuria (1,713 g/l [724–2,760 g/l]; p=0.029) or macroalbuminuria (1,648 g/l [568–3,394 g/l]; p=0.019). There was a significant correlation between MBL and estimated glucose disposal rate, but not between MBL and C-reactive protein or IL-6 levels in univariate analysis. However, in a multiple regression analysis, HbA1c was the single variable independently associated with MBL (±SEM: 0.26±0.08; p=0.003).Conclusions/interpretation MBL concentrations are increased in type 1 diabetic patients with diabetic nephropathy. MBL was not associated with low-grade inflammatory markers.     

Association of a polymorphism in the gene encoding phosphoenolpyruvate carboxykinase 1 with high-density lipoprotein and triglyceride levels

Aims/hypothesis Phosphoenolpyruvate carboxykinase (PCK) is the key enzyme involved in the regulation of gluconeogenesis. The aim of this study was to identify genetic polymorphisms in potential candidate genes for type 2 diabetes by sequencing all exons in the PCK genes (PCK1 and PCK2), and examining the association with type 2 diabetes and diabetic phenotypes in a Korean population (775 type 2 diabetic patients and 316 normal control subjects).Materials and methods Twenty-two polymorphisms in PCK1 and PCK2 were identified in a Korean population (n=24) by direct DNA sequencing. The TaqMan genotyping method was applied for genotyping the remainder of the study population. Associations of PCK polymorphisms with the risk of type 2 diabetes and diabetic phenotypes were analysed using logistic and multiple regressions, adjusting for age, sex and BMI.Results Although no significant associations between the genetic polymorphisms in PCK genes and the risk of type 2 diabetes were detected, in further haplotype analysis, one of the common haplotypes, PCK1 ht3, revealed susceptibility to type 2 diabetes (p=0.006). One 3 untranslated region (UTR) single nucleotide polymorphism (SNP) also showed an association with HDL levels among non-diabetic control subjects: individuals homozygous for the major allele (T/T) had the lowest HDL level (1.11±0.32 mmol/l), heterozygotes (T/C) had an intermediate level (1.27±0.37 mmol/l), and those homozygous for the minor allele (C/C) had the highest level (1.39±0.28 mmol/l) (p=0.000003). This 3 UTR SNP was also associated with triglyceride levels, with a lower triglyceride level observed among individuals who were homozygous for the minor allele (C/C) than among those who were not.Conclusions/interpretation The strong genetic association of HDL and triglyceride levels with variation/haplotype information identified in this study would be useful for further genetic epidemiological studies of this important gene.Electronic supplementary material Supplementary material is available for this article at and accessible for authorised users.     

Association between a polymorphism in the angiotensin-converting enzyme gene and microvascular complications in Japanese patients with NIDDM

Summary The relationship between diabetic nephropathy and an insertion (I)/deletion (D) polymorphism in intron 16 of the angiotensin-converting enzyme (ACE) gene is still under debate. The association of ACE gene polymorphism with nephropathy and retinopathy was therefore examined in 362 Japanese patients with non-insulin-dependent diabetes mellitus (NIDDM) and 105 healthy control subjects. Distribution of the ACE genotype did not differ between healthy control subjects and diabetic patients without complications. However, the frequency of the D allele was significantly higher in the diabetic subjects with nephropathy than in those without (0.32 in normoalbuminuric patients vs 0.44 in albuminuria patients with albuminuria) (²=7.7; p=0.006). There was no significant association between ACE genotype and retinopathy. These observations thus demonstrate a significant association of the ACE gene polymorphism with nephropathy, but not with retinopathy, in Japanese patients with NIDDM.Abbreviations ACE Angiotensin-converting enzyme - IDDM insulin-dependent diabetes mellitus - NIDDM non-insulin-dependent diabetes mellitus - UAI urinary albumin index - PCR polymerase chain reaction     

Angiotensin-I converting enzyme insertion/deletion polymorphism and its association with diabetic nephropathy: a meta-analysis of studies reported between 1994 and 2004 and comprising 14,727 subjects

Aims/hypothesis The ACE insertion/deletion polymorphism has been examined for association with diabetic nephropathy over the past decade with conflicting results. To clarify this situation, we conducted a comprehensive meta-analysis encompassing all relevant studies that were published between 1994 and 2004 and investigated this potential genetic association.Methods A total of 14,727 subjects from 47 studies was included in this meta-analysis. Cases (n=8,663) were type 1 or 2 diabetic subjects with incipient (microalbuminuria) or advanced diabetic nephropathy (proteinuria, chronic renal failure, end-stage renal disease). Control subjects (n=6,064) were predominantly normoalbuminuric.Results No obvious publication bias was detected. Using a minimal-case definition based on incipient diabetic nephropathy, subjects with the II genotype had a 22% lower risk of diabetic nephropathy than carriers of the D allele (pooled odds ratio [OR]=0.78, 95% CI=0.69–0.88). While there was a reduced risk of diabetic nephropathy associated with the II genotype among Caucasians with either type 1 or type 2 diabetes, the association was most marked among type 2 diabetic Asians (Chinese, Japanese, Koreans) (OR=0.65, 95% CI=0. 51–0.83). This OR is significantly different from the OR of 0.90 (95% CI= 0.78–1.04) that was obtained for type 2 diabetic Caucasians (p=0.019). Using a stricter case definition based on advanced diabetic nephropathy, a comparable risk reduction of 24–32% was observed among the three subgroups, although statistical significance was reached only among Asians.Conclusions/interpretation The results of our meta-analysis support a genetic association of the ACE Ins/Del polymorphism with diabetic nephropathy. These findings may have implications for the management of diabetic nephropathy using ACE inhibitors especially among type 2 diabetic Asians.     

Angiotensin Converting Enzyme Insertion/Deletion Polymorphism and Renoprotection in Diabetic and Nondiabetic Nephropathies

Despite the huge amount of studies looking for candidate genes, the ACE gene remains the unique, well-characterized locus clearly associated with pathogenesis and progression of chronic kidney disease, and with response to treatment with drugs that directly interfere with the renin angiotensin system (RAS), such as angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists (ARA). The II genotype is protective against development and progression of type I and type II nephropathy and is associated with a slower progression of nondiabetic proteinuric kidney disease. ACE inhibitors are particularly effective at the stage of normoalbuminuria or microalbuminuria in both type I and type II diabetics with the II genotype, whereas the DD genotype is associated with a better response to ARA therapy in overt nephropathy of type II diabetes and to ACE inhibitors in male patients with nondiabetic proteinuric nephropathies. The role of other RAS or non-RAS polymorphisms and their possible interactions with different ACE I/D genotypes are less clearly defined. Thus, evaluating the ACE I/D polymorphism is a reliable tool to identify patients at risk and those who may benefit the most of renoprotective therapy with ACE inhibitors or ARA. This may guide pharmacologic therapy in individual patients and help design clinical trials in progressive nephropathies. Moreover, it might help optimize prevention and intervention strategies at population levels, in particular, in countries where resources are extremely limited and 1 million patients continue to die every year of cardiovascular or renal disease.More than one hundred years have elapsed since 1898, when Tigerstedt and Bergman at Karolinska Institute observed that injection of a crude extract of rabbit kidney raised the blood pressure (BP) in dogs (1). The extract contained a substance with long-lasting pressure effects that they named renin. Curiously, however, this seminal observation remained almost unnoticed until 1934, when Goldblatt showed that clamping of a kidney artery induced hypertension in the dog, an effect associated with the release of a vasopressor substance in the ipsilateral renal vein (2). Demonstrating an enhanced release of pressure substances from damaged kidneys into the circulation provided a reasonable pathophysiologic explanation for the well-known association between kidney disease and arterial hypertension and revived the seminal intuition of Claude Bernard that an endocrine mechanism, the milieu interior, is involved in the regulation of the systemic BP. A few years later, the concept of a system specifically involved in BP control came to the light with discovery by Page and Braun-Menendez that renin is a peptidase that produces the vasoconstrictor peptide angiotensin II from the precursor angiotensinogen (3). Since then, multidisciplinary research involving clinical scientists, pathologists, biochemists, physiologists, molecular biologists, and, more recently, geneticists, allowed identifying and characterizing many other components of the renin-angiotensin system (RAS), including the angiotensin-converting-enzyme (ACE), and specific receptors for the main RAS effectors, such as angiotensin II and aldosterone (4–10). Even more important, it soon became evident that RAS, in addition to controlling the systemic BP, may also have many other effects. Navar and Rosivall showed that angiotensin II enhances the tone of the postglomerular arteriole (11), which induces glomerular hypertension and increases the filtration fraction (12), hemodynamic adaptations that in the long-term may cause glomerular damage and dysfunction (13). Angiotensin II may also induce mesangial and vascular cell hypertrophy (14) and sustain chronic inflammation, ischemia, and fibrosis in proteinuric kidneys (15).The awareness that chronic RAS activation could have a key role in widely diffused, highly invalidating and often fatal diseases, boosted research efforts aimed to better characterize the system and to guide the development of intervention strategies aimed to limit its effects on vessels and tissues. Along this line, a major contribution came from novel molecular biologic techniques that, since the early 1980s, allowed to clone the genes encoding for various components of the system, such as renin, ACE and angiotensinogen (AGT), as well as for angiotensin II receptors type 1 (AT1R) and type 2 (AT2R) DNA cloning allowed also to detect gene polymorphisms of several components of the RAS, which helped geneticists to better understand the complex relationships between RAS and disease. In 1990, Rigat et al. (16) first described the insertion (I)/ deletion (D) polymorphism of the ACE gene, a major locus that accounts for approximately 50% of the total phenotypic variance of circulating and tissue ACE. Subjects carrying the D allele were found to have increased systemic and renal ACE levels, whereas those with the II genotype had the lowest ACE expression (17). Evidence that ACE is a limiting factor for angiotensin II synthesis, and therefore for most of the systemic and renal effects of the RAS, pushed researchers to focus a large part of genetic analyses of the RAS on the study of ACE I/D polymorphism. Thus, over the last decade, several studies converged to indicate that risk for development and progression of diabetic (18) and nondiabetic (19–21) chronic renal disease, as well as of related cardiovascular complications (22), varies with different I/D genotypes.With the development of captopril, the ancestor of a new class of antihypertensive agents, the ACE inhibitors, developed with the specific objective of limiting uncontrolled RAS activation in renovascular disease, Ondetti et al. (23) paved the way to a series of pharmacologic studies that provided new and largely unexpected insights on the concert of RAS effects. Studies found that RAS inhibition may lower the BP in patients with ischemic kidney disease and in a large proportion of those with essential hypertension as well, including patients with low plasma renin activity (24). Moreover, with time, the area of application of RAS inhibitor therapy extended from arterial hypertension to left ventricular hypertrophy and congestive heart failure, prevention of stroke, atherosclerosis, atrial fibrillation, and prevention and treatment of chronic kidney disease. Evidence that RAS inhibitors can be effective even in patients without signs of activity of the system is a major challenge to explore the possibility that the pathophysiology of cardiovascular and renal disease(s) are somehow linked to the function of renin angiotensin axis. Better understanding of the complex interactions of the RAS with hemodynamic and metabolic abnormalities of patients with hypertension, diabetes or renal disease, as well as with genetic variants of other pathways possibly involved in target organ damage, will hopefully open novel perspective of therapy for these high-risk patients. Evaluating these interactions, however, is difficult: large and well-characterized patient populations with homogeneous genetic backgrounds and univocally defined and clinically relevant outcomes are needed to give enough power to the analyses and limit the risk of random data fluctuations. Moreover, studies must take into consideration the role of acquired and environmental factors that may vary from one experimental setting to the other and may confound data interpretation. Unfortunately, most of the studies performed so far failed to satisfy the above requirements, largely because of the too small sample size or the heterogeneity of studied populations; and this may explain why data on the role of the RAS, and in particular of the ACE gene, in human disease were often inconclusive and sometimes even conflicting between different studies.Thus, our major task was to provide a critical overview of available evidence, trying to focus on most robust findings and, where possible, clean available information from unreliable or misleading data. We also discussed less solid data on other genetic factors that, combined with different ACE I/D genotypes, may contribute to the large interindividual variability in disease susceptibility and treatment response. Patients with diabetic and nondiabetic renal disease were treated separately to assess whether the same genetic factors may play a similar or different role in these two clinical settings. On the contrary, dissecting data on type I from those on type II diabetics was often difficult because many studies considered these patients together and only occasionally provided aggregate data in the two populations analyzed separately. We focused on papers considering microalbuminuria or macroalbuminuria, proteinuria, kidney function, and end-stage kidney disease (ESKD) as outcome variables. Relevant studies were retrieved by a literature search performed in MEDLINE (from 1996 to most recent) and EMBASE (from 1980 to most recent) by using specific key words according to considered genetic (RAS polymorphisms), disease (diabetic nephropathy, nondiabetic nephropathy) and drug categories (ACE inhibitors, angiotensin II receptor antagonism [ARA]). Randomized clinical trials were identified and selected for the meta-analysis according to the search strategy developed for the Cochrane Collaboration. Data on renal transplant patients were not considered.     

Polymorphisms of the renin-angiotensin system genes in Brazilian patients with lupus nephropathy

Genetic polymorphisms of the renin-angiotensin system (RAS) has been associated with cardiovascular events and the progression of nephropathy in several diseases. The objective of this study was to evaluate a possible association of the genetic polymorphisms of RAS with the development and/or progression of lupus nephritis in a Brazilian population. Seventy-five SLE patients with lupus nephropathy (LN group) were compared to 72 SLE patients without LN (SLE group) and 65 healthy individuals (CONTROL group), of sex and ethnic matched, in a Brazilian population sample. Mean global follow-up was 9 +/- 6 years for lupus without nephropathy and 11 +/- 7 years for lupus nephropathy. Following the extraction of genomic DNA from the leukocytes in the peripheral blood, angiotensin converting enzyme (ACE I/D), angiotensinogen (AGT M(235)T) and angiotensin II type 1 receptor (AGTR1 A(1166)C) genotypes were determined by the polymerase chain reaction. No significant difference of ACE, AGT and AGTR1 genotypes distribution between groups was observed in this study. There was no significant association between the variables of the RAS genotypes and the presence of hypertension in SLE. However, an increased frequency ofDD genotype (ACE I/D) was observed in SLE patients with LN who progressed to CRF compared to healthy controls (DD 60%, DI 26.7%, II 13.3% versus 27.7%, 60% and 12.3%, respectively; chi2 = 6.299, P = 0.0429). In the population studied, there was no influence of the RAS genetic polymorphisms in the development of lupus nephropathy, but the progression to CRF was associated with ACE DD polymorphism.     

Pre-eclampsia but not pregnancy-induced hypertension is a risk factor for diabetic nephropathy in type 1 diabetic women

Aims/hypothesis Our aim was to study whether pre-eclampsia and pregnancy-induced hypertension are predictors of diabetic nephropathy in type 1 diabetic women. Materials and methods A total of 203 type 1 diabetic women, who were pregnant between 1988 and 1996 and followed at the Department of Obstetrics and Gynaecology in Helsinki, were re-assessed after an average of 11 years within the nationwide, multi-centre Finnish Diabetic Nephropathy Study. Diabetic nephropathy was defined as microalbuminuria, macroalbuminuria or end-stage renal disease. Results Patients with prior pre-eclampsia had diabetic nephropathy more often than patients with a normotensive pregnancy (diabetic nephropathy vs normal albumin excretion rate: 41.9% vs 8.9%; p<0.001), whereas patients with a history of pregnancy-induced hypertension did not (10.3% vs 8.9%; p=0.81). CHD was more prevalent in patients with a history of pre-eclampsia than in patients with a normotensive pregnancy (12.2% vs. 2.2%; p=0.03). Pre-eclampsia (odds ratio [OR] 7.7, 95% CI 1.6-36.1; p=0.01) and HbA_1c (OR 2.0, 95% CI 1.1-3.8; p<0.05) were associated with incident diabetic nephropathy even when adjusted for follow-up time, BMI, smoking, diabetes duration and age. Conclusions/interpretation These data suggest that a history of pre-eclamptic pregnancy but not pregnancy-induced hypertension is associated with an elevated risk of diabetic nephropathy. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible to authorised users.     

Association analysis of podocyte slit diaphragm genes as candidates for diabetic nephropathy

Aims/hypothesis The slit diaphragm is an adhesion and signalling protein complex linking the interdigitating podocyte foot processes in the kidney glomerulus, and mutations in slit diaphragm-associated genes result in severe proteinuria. Here we report a genetic association analysis of four slit diaphragm genes, LRRC7, KIRREL, NPHS2 and ACTN4, in a Finnish diabetic nephropathy cohort. Materials and methods A total of 40 single nucleotide polymorphisms (SNPs) were genotyped in 1103 patients with type 1 diabetes. The patients were classified according to their renal status, and the genotype data were analysed in a cross-sectional case–control setting. To confirm positive associations, four SNPs were genotyped in 1,025 additional patients with type 1 diabetes. Results No associations with diabetic nephropathy were observed for any of the analysed SNPs. The SNPs were not associated with the time from the onset of diabetes to the diagnosis of nephropathy or with glomerular filtration rate or AER as quantitative variables. In a sex-specific sub-analysis, the variants rs979972 and rs749701 in the first intron of ACTN4 were nominally associated with diabetic nephropathy in females, with odds ratios of 1.81 (95% CI 1.18–2.79, p = 0.007) and 1.93 (95% CI 1.26–2.96, p = 0.003) respectively. Conclusions/interpretation Our study has not found any evidence that common variants in LRRC7, KIRREL, NPHS2 and ACTN4 contribute to susceptibility to diabetic nephropathy in Finnish patients with type 1 diabetes. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

Variation near the hepatocyte nuclear factor (HNF)-4α gene associates with type 2 diabetes in the Danish population

Aims/hypothesis The hepatocyte nuclear factor (HNF)-4 is an orphan nuclear receptor, which plays crucial roles in regulating hepatic gluconeogenesis and insulin secretion. The gene encoding HNF-4 (HNF4A) is located on chromosome 20q12–q13 in a region that in several studies has shown linkage with type 2 diabetes. Recently, two independent studies identified single nucleotide polymorphisms (SNPs) in a 90-kb region spanning HNF4A, which showed strong association with type 2 diabetes in the Finnish and Ashkenazi Jewish populations. In an attempt to replicate and extend these findings, we selected four SNPs in the same HNF4A region, which in the Finnish and Ashkenazi Jewish populations were associated with type 2 diabetes, and examined their relationships with type 2 diabetes and prediabetic phenotypes in the Danish Caucasian population.Methods The rs1884614, rs2425637, rs1885088 and rs3818247 were analysed in case-control studies of 1387, 1429, 1417 and 1371 type 2 diabetic patients and 4766, 4727, 4665 and 4748 glucose-tolerant subjects respectively. Genotype–quantitative trait analyses comprised 4430, 4394, 4336 and 4413 middle-aged glucose-tolerant subjects from the population-based Inter99 cohort for the rs1884614, rs2425637, rs1885088 and rs3818247 respectively.Results The risk allele of the rs1884614, which is located 4 kb upstream of the HNF4A P2 promoter, was associated with type 2 diabetes (odds ratio [OR]=1.14, p=0.02) and with a subtle increase in post-OGTT plasma glucose levels in glucose-tolerant subjects (additive model, p=0.05).Conclusions/interpretation Consistent with results from studies of Finnish and Ashkenazi Jewish subjects, variation near the P2 region of HNF4A is associated with type 2 diabetes in the Danish population.     

Urinary angiotensin-converting enzyme activity in type 2 diabetes mellitus: its relationship to diabetic nephropathy

Urinary angiotensin-converting enzyme (ACE) and urinaryN-acetyl--d-glucosaminidase (NAG) were measured after a 5-year interval in 38 non-azotemic type 2 diabetic patients. Of these patients at baseline, 16 had nil nephropathy, 15 had incipient nephropathy, and 7 had overt nephropathy. During the follow-up, 6 and 1 of the 16 patients with nil nephropathy developed incipient and overt nephropathy, respectively. Four of the 15 patients with incipient nephropathy progressed to overt nephropathy. The 7 patients with overt nephropathy continued to have overt nephropathy, with slight azotemia in one. Urinary ACE and NAG levels were normal at baseline and showed no significant elevations at follow-up in the patients with nil nephropathy, no significant changes at baseline and modest elevations at follow-up in the patients with incipient nephropathy, and high at baseline and marked elevations at follow-up in the patients with overt nephropathy. In all patients, urinary ACE during the follow-up was positively correlated with urinary albumin or NAG, but not with glomerular filtration rate. Urinary ACE may be of poor prognostic value for the follow-up of diabetic patients, which is at variance with urinary albumin.     

Genetic polymorphism of renin-angiotensin system is not associated with diabetic vascular complications in Japanese subjects with long-term insulin dependent diabetes mellitus.

In a hospital cohort study, we examined whether or not ACE (Angiotensin-I converting enzyme) and AGT (Angiotensinogen) gene polymorphisms were associated with the development of nephropathy in long-term Japanese insulin-dependent diabetes mellitus (IDDM) patients with or without proliferative retinopathy, and whether or not the polymorphisms were associated with an arteriosclerotic family history in first degree relatives of the patients. A total of 201 patients with IDDM for more than 10 years and 159 patients with IDDM for more than 15 years were randomly selected in our hospital. All patients received uniform diabetes management and were divided into three groups, no nephropathy, incipient nephropathy and clinical nephropathy groups. There were no differences in clinical characteristics excluding urinary albumin to creatinine ratio and systolic blood pressure between the three groups. ACE I/D polymorphism was related to plasma ACE activity, but there were no associations between ACE I/D polymorphism and the development of diabetic nephropathy, nor was renal deterioration observed in patients with proliferative retinopathy even in those with a history of diabetes for more than 15 years. The AGT polymorphism did not have an additive effect on the association between ACE polymorphism and the development of diabetic nephropathy in patients with or without retinopathy. Development of diabetic nephropathy in the patients with or without proliferative retinopathy did not result in ACE or AGT polymorphisms. On the other hand, the ACE DD genotype was associated with a family history of ischemic heart disease in first degree relatives (X2 score = 9.04, P < 0.05). ACE and AGT gene polymorphisms may not play a role in the protective or accelerative effect against the development of diabetic nephropathy in the patients with or without proliferative retinopathy, but ACE gene polymorphism might be related to an arteriosclerotic family history in Japanese IDDM patients.     

Angiotensin converting enzyme (ACE) gene polymorphism increases the susceptibility of diabetic nephropathy in Western Indian Type 2 diabetic patients

Angiotensin-converting enzyme (ACE) gene has been associated with the pathogenesis and progression of chronic kidney diseases. Diabetic nephropathy has become leading cause of renal end stage disease (ESRD). An I/D polymorphism of angiotensin-converting enzyme (ACE) gene has been suggested as one of the risk factors for the progression of diabetic nephropathy. We analyzed the genotype and allele frequency distribution of ACE gene in 166 Type 2 diabetic patients without any complication (T2DM), 61 with diabetic nephropathy (DN), 50 with non-diabetic nephropathy (NDN) and 50 healthy individuals from western Indian population. ACE genotype was analyzed by PCR method. The D allele distribution for the ACE I/D polymorphisms was not significantly different between control group and patients with T2DM without any complication (41.0% vs. 45.2%, P?=?0.461) and between control subjects and patients with non-diabetic nephropathy (NDN) (41.0% vs. 44.0%, P?=?0.668). Frequency of the D allele (63.9% vs. 45.2%, P?<?0.001) and DD genotype (I allele noncarrier) (44.3% vs. 25.3%, P?=?0.006) of ACE gene was significantly higher in patients with diabetic nephropathy (DN) than in patients with T2DM without any complication. Results of the present study indicate that ACE gene polymorphism does not have significant influence on development of diabetes mellitus and nondiabetic nephropathy, whereas, the DD polymorphism in ACE gene has been associated with the development of diabetic nephropathy in the Western Indian population.     

Polymorphisms of human paraoxonase 1 gene (PON1) and susceptibility to diabetic nephropathy in Type I diabetes mellitus

Aims/hypothesis. Oxidative stress is a putative mechanism in the development of diabetic nephropathy. Paraoxonase gene 1 is an HDL-bound enzyme that protects tissues against oxidative damage. Three common polymorphisms of paraoxonase gene 1, T-107C in the promoter, Leu54Met and Gln192Arg, that modify paraoxonase activity have been associated with cardiovascular disease. This study aimed to find whether these polymorphisms also contribute to the development of diabetic nephropathy. Methods. The association between diabetic nephropathy and these three polymorphisms was examined in a case-control study. For this purpose, genomic DNA was collected from 188 patients with Type I (insulin-dependent) diabetes mellitus and diabetic nephropathy and from 179 unrelated patients with Type I diabetes but without diabetic nephropathy despite the duration of diabetes of 15 or more years. Results. The genotype and allele frequencies for each of the three polymorphisms (T-107C, Leu54Met and Gln192Arg) were similar in cases and control subjects. Conclusion/interpretation. The three polymorphisms in paraoxonase gene 1 that have been associated with serum levels of paraoxonase are not associated with diabetic nephropathy. We show that this genetically determined component of the antioxidant capacity of HDL does not play a critical part in the development of diabetic nephropathy. [Diabetologia (2000) 43: 1540–1543] Received: 14 July 2000 and in revised form: 21 August 2000     

Effect of common polymorphisms in the HNF4α promoter on susceptibility to type 2 diabetes in the French Caucasian population

Aims/hypothesis The gene encoding HNF-4, an orphan nuclear receptor playing critical roles in embryogenesis and metabolism by regulating gene expression in pancreatic beta cells, liver, and other tissues, is localised to chromosome 20q13, where linkage to type 2 diabetes has been shown in multiple studies. As two reports have independently demonstrated a convincing association with variants adjacent to the HNF-4 P2 promoter in Finnish and Ashkenazi Jewish populations, we evaluated their contribution to diabetes risk in the French Caucasian population.Methods Genotypes for four haplotype tag SNPs were analysed for association with diabetes in a case-control study of 744 unrelated type 2 diabetic patients and 686 normoglycaemic subjects, and for linkage in 148 diabetic families in whom significant linkage to the HNF4 region had been shown.Results The association seen in the Finnish and Ashkenazi studies for SNPs rs2144908 and rs1884614 located within a haplotype block encompassing the beta cell promoter P2 of HNF-4 was not replicated in our study; in French Caucasians the minor allele prevalence was increased in control subjects [odds ratio (OR) 0.80, uncorrected p=0.022 for rs2144908; OR 0.82 uncorrected p=0.058 for rs1884614]. Furthermore, none of the SNPs tested in the French familial sample was associated with diabetes, nor do they appear to contribute to the linkage.Conclusions/interpretation None of the previously associated SNPs confer an increased risk for diabetes in French Caucasians. A large meta-analysis of association studies will determine whether there is a consistent association between particular SNPs upstream of HNF-4 and type 2 diabetes in several ethnic groups.     

Apolipoprotein(a) and cardiovascular disease in Type 2 (non-insulin-dependent) diabetic patients with and without diabetic nephropathy

Summary The relative mortality from cardiovascular disease is on average increased five-fold in Type 2 (non-insulin-dependent) diabetic patients with diabetic nephropathy compared to non-diabetic subjects. We assessed the possible contribution of dyslipidaemia in general and elevated serum apolipoprotein(a) (apo(a)) in particular. Type 2 diabetic patients with normo-, micro- and macroalbuminuria were compared with healthy subjects. Each group consisted of 37 subjects matched for age, sex and diabetes duration. Serum creatinine in the nephropathy group was 105 (54–740) mol/l. The prevalence of ischaemic heart disease (resting ECG, Minnesota, Rating Scale) was 57, 35, 19 and 2% in macro-, micro- and normoalbuminuric diabetic patients and healthy subjects, respectively. The prevalence of ischaemic heart disease was higher in all diabetic groups as compared to healthy subjects (p<0.05), and higher in macroalbuminuric as compared to normoalbuminuric diabetic patients (p<0.01). There was no significant difference between apo(a) in the four groups: 161 (10–1370), 191 (10–2080), 147 (10–942), 102 (10–1440) U/l (median (range)) in macro-, micro- and normoalbuminuric groups and healthy subjects. Serum total-cholesterol, HDL-cholesterol and LDL-cholesterol were not significantly different when comparing healthy subjects and each diabetic group. Apolipoprotein A-I was lower (p<0.05) in all diabetic groups as compared to healthy subjects (nephropathy vs healthy subjects): 1.50±0.25 vs 1.69±0.32 g/l (mean ± SD). Triglyceride was higher (p<0.05) in patients with nephropathy and microalbuminuria as compared to healthy subjects (nephropathy vs healthy subjects): 2.01 (0.66–14.7) vs 1.09 (0.41–2.75) mmol/l (median (range)). Apolipoprotein B was higher (p<0.02) in patients with nephropathy as compared to the other three groups (nephropathy vs healthy subjects): 1.54±0.47 vs 1.33±0.30 g/l. In conclusion, our case-control study has confirmed that Type 2 diabetic patients with increased urinary albumin excretion frequently suffer from dyslipidaemia and cardiovascular disease. However, our study revealed no significant elevation in serum concentration of apo(a) in patients with diabetic nephropathy, but numbers were small.     

Association of sequence variations in the gene encoding adiponectin receptor 1 (ADIPOR1) with body size and insulin levels. The Finnish Diabetes Prevention Study

Aims/hypothesis Adiponectin is a circulating peptide derived from adipose tissue. It mediates its insulin-sensitising and anti-atherogenic effects on target tissues through two known receptors, adiponectin receptors 1 and 2 (ADIPOR1; ADIPOR2), which are encoded by the genes ADIPOR1 and ADIPOR2. Our aim was to study the association of ADIPOR1 gene variations with body size and risk of type 2 diabetes in subjects with impaired glucose tolerance, who participated in the Finnish Diabetes Prevention Study (DPS).Subjects and methods We selected seven single nucleotide polymorphisms (SNPs) of the ADIPOR1 gene to perform association studies with anthropometrics and metabolic parameters at baseline, and with the risk of type 2 diabetes during the 3-year follow-up in the DPS study population. Both single SNP analysis and haplotype effects were studied.Results Three out of seven markers studied (rs10920534, rs22757538 and rs1342387) were significantly associated with various body size measurements including weight, height, waist and hip circumference, sagittal diameter and body mass index. Furthermore, three markers (rs10920534, rs12045862 and rs7539542), of which two were different from those associating with body size, were linked to fasting and 2-h insulin levels, particularly in men at baseline. The haplotype analysis with five markers revealed seven major haplotypes in the DPS study population. The haplotype effects on body size measures were in line with those of single SNP analysis. However, none of the markers were associated with the risk of type 2 diabetes.Conclusions/interpretation Our findings suggest that ADIPOR1 has a putative role in the development of body size, and that traits for central adiposity and insulin resistance may be dissociated from each other.Electronic Supplementary Material Supplementary Material is available in the online version of this article at     

Renoprotective effects of vasopeptidase inhibition in an experimental model of diabetic nephropathy

Aims Although ACE inhibitors slow progression of diabetic renal disease, the mortality and morbidity is still high. As other hormonal factors are involved, inhibition of vasopeptidases could further reduce progression. We studied dual inhibition of angiotensin converting enzyme and neutral endopeptidase in a model of progressive diabetic renal injury. The major endpoints were reductions in systemic blood pressure, albuminuria and renal structural injury.Methods Diabetic spontaneously hypertensive rats were treated with the ACE inhibitor perindopril (mg·kg^–1·day^–1) or the vasopeptidase inhibitor omapatrilat at doses of 10 (oma10) and 40 (oma40) mg·kg^–1·day^–1 for 32 weeks. In vivo ACE and NEP inhibition was quantitated by in vitro autoradiography. Renal structural injury was assessed by measurement of the glomerulosclerotic (GS) index and tubulointerstitial area (TI). The expression of transforming growth factor , -inducible gene-h3 and nephrin were also quantitated.Results Despite a similar reduction in blood pressure by perindopril and oma10, greater attenuation of albuminuria was afforded by oma10, with a complete amelioration observed with oma40. Oma40 lead to a 33% reduction in renal NEP binding and this was associated with less albuminuria and prevention of GS, TI area and overexpression of TGF and ig-h3. Diabetes-associated reduction in nephrin expression was restored by both drugs.Conclusion/Interpretation These findings suggest that other vasoactive mechanisms in addition to angiotensin II are important in the prevention of diabetic nephropathy, and that vasopeptidase inhibition might confer an advantage over blockade of the RAS alone in the treatment of diabetic renal disease.Abbreviations ACEi angiotensin converting enzyme inhibitor - AII angiotensin II - ig-h3 -inducible gene-h3 - GSI glomerulosclerotic index - NEP neutral endopeptidase - Oma omapatrilat - Per perindopril - PRA plasma renin activity - RAS renin-angiotensin system - SBP systolic blood pressure - TIA tubulointerstitial area - VPI vasopeptidase inhibitor     

Examination of two genetic polymorphisms within the renin-angiotensin system: no evidence for an association with nephropathy in IDDM

Summary Premature cardiovascular disease is common in insulin-dependent diabetic (IDDM) patients who develop diabetic nephropathy. Genetic polymorphism within the renin-angiotensin system has been implicated in the aetiology of a number of cardiovascular disorders; these loci are therefore candidate genes for susceptibility to diabetic renal disease. We have examined the angiotensin converting enzyme insertion/deletion polymorphism and angiotensinogen methionine 235 threonine polymorphism in a large cohort of Caucasian patients with IDDM and diabetic nephropathy. Patients were classified as having nephropathy by the presence of persistent dipstick positive proteinuria (in the absence of other causes), retinopathy and hypertension (n=242). Three groups were examined for comparison: ethnically matched non-diabetic subjects (n=187); a geographically defined cohort of newly diagnosed diabetic patients (n=341); and IDDM patients with long duration of disease (>15 years) and no evidence of overt nephropathy (n=166). No significant difference was seen in distribution of angiotensin converting enzyme or angiotensinogen genotypes between IDDM patients with nephropathy and recently diagnosed diabetic subjects (p=0.282 and 0.584, respectively), nor the long-duration non-nephropathy diabetic subjects (p=0.701 and 0.190, respectively). We conclude that these genetic loci are unlikely to influence susceptibility to diabetic nephropathy in IDDM in the United Kingdom.Abbreviations IDDM Insulin-dependent diabetes mellitus - ACE angiotensin converting enzyme - PCR polymerase chain reaction - LDNN long duration-non-nephropathy group - I/D insertion/deletion - RAS renin-angiotension system     

Captopril and atenolol are equally effective in retarding progression of diabetic nephropathy

Summary The progression of diabetic nephropathy can be positively influenced by maintaining a low blood pressure level. This has been shown in studies with conventional antihypertensive treatment as well as with ACE inhibitors. Whether the latter group of drugs is more effective remains to be proven and was the aim of our study. In a prospective randomized study we compared the effects of ACE inhibition and -blockade on retarding progression of renal function in IDDM patients with an early stage of overt diabetic nephropathy. Twenty-nine patients were studied for 2 years, 15 were randomized for treatment with captopril and 14 for atenolol. Every 6 weeks blood pressure and urinary albumin and total protein excretion were measured. GFR was measured every 6 months as ⁵¹Cr-EDTA clearance. Baseline values for blood pressure, renal function and albuminuria were identical in the two groups. The effect of both drugs on blood pressure was not significantly different. In the captopril-treated patients MAP before and after 2 years was 110±3 (SEM) and 100±2 mm Hg, respectively and in the atenolol-treated patients 105±2 vs 101±2 mm Hg. Both drugs reduced albuminuria and total proteinuria to the same extent. With captopril albuminuria decreased from 1549 (989–2399) to 851 (537–1380) mg/24 h and proteinuria from 2.5 (1.6–3.8) to 1.2 (0.8–1.8) g/24 h. With atenolol albuminuria decreased from 933 (603–1445) to 676 (437–1047) mg/ 24 h and proteinuria from 1.5 (1.0–2.4) to 0.9 (0.6–1.5) g/24 h. The rate of decline of GFR was similar with both treatments, on captopril –4.9±2.1 and on atenolol –3.7±1.6 ml · min^–1· year^–1. No major side effects with either drug were observed. We conclude that, in this 2-year study, captopril and atenolol are equally effective in retarding progression of diabetic nephropathy.Abbreviations IDDM insulin-dependent diabetes mellitus - ACE angiotensin converting enzyme - ECC endogenous creatinine clearance - MAP mean arterial pressure - GFR glomerular filtration rate