Endothelial nitric oxide synthase gene polymorphisms and renal responsiveness to RAS inhibition therapy in type 2 diabetic Asian Indians

Association between nitric oxide synthase (NOS3) gene polymorphisms and diabetic nephropathy: An updated meta-analysis

Polymorphisms located within NOS3 gene have been investigated as susceptibility variants for diabetic nephropathy (DN) in type 2 diabetes mellitus (T2DM) in a large number of studies. However, these previous articles yielded inconsistent results and we aimed at elucidating the impact of NOS3 variants on DN risk in T2DM by conducting an updated systematic data synthesis. A total of 36 studies (12,807 participants) were selected for qualitative data synthesis, while 33 records with 11,649 subjects were included in the meta-analysis. The pooled analysis demonstrated the association of minor alleles of rs2070744 and rs1799983 with an increased susceptibility to DN (P < 0.001 and P = 0.015 for allelic model, respectively). For both of these variants, a significant effect of subgrouping according to ethnicity was found. Rs869109213 displayed an association with DN susceptibility, with pooled effect measures indicating a predisposing effect of the minor allele a (Prec = 0.002, ORrec = 1.960, 95%CI 1.288-2.983; Paavs. bb = 0.001, ORaavs. bb = 2.014, 95%CI 1.316-3.083). These findings support the effects of NOS3 variants on the risk of developing DN in T2DM.

Associations between the polymorphisms of main components in PI3K/Akt pathway and risk of diabetic kidney disease: A meta-analysis

AIMS

Diabetic kidney disease (DKD) is a severe microvascular complication frequently associated with type 1 and type 2 diabetes mellitus. The objective of this work was to evaluate the relevance of PI3K/Akt pathway polymorphisms and DKD susceptibility by a meta-analysis.

METHODS

Case-control studies related to the relationship between PI3K/Akt pathway polymorphisms and DKD risk were searched from Pubmed, Embase, Cochrane Library, SINOMED, CNKI, and Wanfang databases. Statistical analysis and heterogeneity test were conducted by Review Manager 5.4.

RESULTS

Totally, 52 eligible studies were enrolled, including seven single nucleotide polymorphisms (SNPs) for four genes in the PI3K/AKT pathway (GNB3: rs5443; eNOS: rs1799983, rs869109213, rs2070744; IL-6: rs1800795, rs1800796; TNFα: rs1800629). The "M" allele of eNOS rs1799983 was related to the increased risk of DKD under random effects model, especially in Asian population (Overall:M vs. W: I2  = 75%, OR = 1.29, 95%CI 1.07-1.56; MM + WM vs. WW: I2  = 75%, OR = 1.50, 95%CI 1.21-1.86). The "M" allele of eNOS rs869109213 was implicated with higher prevalence of DKD under random effects model, especially in Asian population (Overall:M vs. W: I2  = 63%, OR = 1.43, 95%CI 1.22-1.68; MM + WM vs. WW: I2  = 50%, OR = 1.36, 95%CI 1.16-1.58; MM vs. WM + WW: I2  = 59%, OR = 2.20, 95%CI 1.41-3.43). The "M" allele of eNOS rs2070744 was implicated with higher prevalence of DKD under random effects model, especially in Indian population (Overall: M vs. W: I2  = 47%, OR = 1.35, 95%CI 1.15-1.59; MM + WM vs. WW: I2  = 45%, OR = 1.32, 95%CI 1.07-1.62; MM vs. WM + WW: I2  = 65%, OR = 2.29, 95%CI 1.39-3.77). The "M" allele of IL-6 rs1800796 was predominately associated with higher DKD risks under random effects model, especially in Asian population (Overall: M versus W: I2  = 23%, OR = 1.49, 95%CI 1.21-1.84; MM + WM vs. WW: I2  = 1%, OR = 1.43, 95%CI 1.15-1.77; MM + WM vs. WW: I2  = 71%, OR = 2.77, 95%CI 1.09-7.06).

CONCLUSIONS

This meta-analysis indicated that polymorphisms in the PI3K/Akt pathway in eNOS rs1799983, rs869109213, rs2070744, and IL-6 rs1800796 were related to the increased risk of DKD.

Epithelial nitric oxide synthases (eNOS) 894 G < T polymorphism and diabetic nephropathy susceptibility: A meta-analysis

Objective

To investigate the epithelial nitric oxide synthases (eNOS) 894 G < T polymorphism and diabetic nephropathy (DN) susceptibility by pooling the open published data.

Methods

Studies relevant to eNOS 894 G < T polymorphism and DN susceptibility published in PubMed, EMBASE, Medline, CNKI, and Wanfang databases were systematically screened by using the text words of endothelial nitric oxide synthase, eNOS, NOS-3, G894T, rs179983, polymorphism, diabetic nephropathy, and DN. The correlation between eNOS 894 G < T polymorphism and DN susceptibility was demonstrated by odds ratio (OR) and corresponding 95% confidence interval (95% CI). The data were combined through fixed or random effect model according to statistical heterogeneity. The publication bias was assessed by Begg’s funnel plot and Egger’s line regression test.

Results

Twenty-six case-control studies relevant to eNOS 894 G < T polymorphism and DN susceptibility were identified by electronic searching of the related databases. Type 2 diabetes mellitus (T2MD) patients with T allele had increased susceptibility to DN compared with G allele under homologous gene model (TT vs GG) (OR = 1.40, 95% CI: 1.16–1.69, p = 0.001), dominant gene model (TT + GT) vs GG (OR = 1.61, 95% CI: 1.30–2.00, p = 0.000) and recessive gene model TT vs (GT + GG) (OR = 1.39, 95% CI: 1.16–1.66, p = 0.000). Publication bias was not statistically significant for homologous and recessive gene model.

Conclusion

Based on the present evidence, DN risk was increased in T2MD cases with T allele compared to G allele.

Association of eNOS and MCP-1 Genetic Variants with Type 2 Diabetes and Diabetic Nephropathy Susceptibility: A Case-Control and Meta-Analysis Study

Type 2 diabetes (T2D) and its secondary complications result from the complex interplay of genetic and environmental factors. To understand the role of these factors on disease susceptibility, the present study was conducted to assess the association of eNOS and MCP-1 variants with T2D and diabetic nephropathy (DN) in two ethnically and geographically different cohorts from North India. A total of 1313 subjects from two cohorts were genotyped for eNOS (rs2070744, rs869109213 and rs1799983) and MCP-1 (rs1024611 and rs3917887) variants. Cohort-I (Punjab) comprised 461 T2D cases (204 T2D with DN and 257 T2D without DN) and 315 healthy controls. Cohort-II (Jammu and Kashmir) included 337 T2D (150 T2D with DN and 187 T2D without DN) and 200 controls. Allele, genotype and haplotype frequencies were compared among the studied participants, and phenotype-genotype interactions were determined. Meta-analysis was performed to investigate the association between the selected variants and disease susceptibility. All three eNOS variants were associated with 1.5-4.0-fold risk of DN in both cohorts. MCP-1 rs1024611 conferred twofold risk towards DN progression in cohort-II, while rs3917887 provided twofold risk for both T2D and DN in both cohorts. eNOS and MCP-1 haplotypes conferred risk for T2D and DN susceptibility. Phenotype-genotype interactions showed significant associations between the studied variants and anthropometric and biochemical parameters. In meta-analysis, all eNOS variants conferred risk towards DN progression, whereas no significant association was observed for MCP-1 rs1024611. We show evidences for an association of eNOS and MCP-1 variants with T2D and DN susceptibility.

Translational science in albuminuria: a new view of de novo albuminuria under chronic RAS suppression

The development of de novo albuminuria during chronic renin–angiotensin system (RAS) suppression is a clinical entity that remains poorly recognized in the biomedical literature. It represents a clear increment in global cardiovascular (CV) and renal risk that cannot be counteracted by RAS suppression. Although not specifically considered, it is clear that this entity is present in most published and ongoing trials dealing with the different forms of CV and renal disease. In this review, we focus on the mechanisms promoting albuminuria, and the predictors and new markers of de novo albuminuria, as well as the potential treatment options to counteract the excretion of albumin. The increase in risk that accompanies de novo albuminuria supports the search for early markers and predictors that will allow practising physicians to assess and prevent the development of de novo albuminuria in their patients.

Correlation of Endothelial Nitric Oxide Synthase Gene Polymorphism (GG, TT and GT Genotype) with Proteinuria and Retinopathy in Type 2 Diabetic Patients

BACKGROUND

Nephropathy is the most important leading cause of end stage renal failure in type 2 diabetic patients, so numerous studies were done to diagnose and evaluate risk factors of diabetic nephropathy (DN). Some gene polymorphisms may be associated with progression or regression of DN, so the aim of this study was to compare prevalence of eNOS gene polymorphism in diabetic patients with controls and its association with diabetic nephropathy.

MATERIALS AND METHODS

In a cross-sectional study, 94 type 2 diabetic patients and 94 normal participants were enrolled. Patients without retinopathy were excluded from this study. For all of the patients, fasting blood sugar (FBS), 2 hours post-prandial (BS), Blood Urea Nitrogen (BUN), Creatinine (Cr), 24 hours urine protein were measured in the case group. Endothelial nitric oxide synthetase gene polymorphism was evaluated in the case and control groups.

RESULTS

There was no significant difference based on age and sex between patients in case and control groups. GG genotype of eNOS was less common in the patient group compared to control group. There was no difference between prevalence of TT, GT or GG genotype based on age and sex. There was no correlation between diabetic retinopathy or proteinuria and genotypes of eNOs.

CONCLUSION

The study showed that in type 2 diabetic patients, NOS gene polymorphism was more common compared to normal population; however, there is no correlation between this gene polymorphism and proteinuria or retinopathy in these patients.

Endothelial nitric oxide synthase (eNOS) 4b/a polymorphism and the risk of diabetic nephropathy in type 2 diabetes mellitus: A meta-analysis

Many studies have accessed the association between eNOS-4b/a polymorphism and the risk of diabetic nephropathy (DN) among type 2 diabetic subjects. However, the results are conflicting and inconclusive. The aim of current meta-analysis was to more precisely estimate the relationship. Pubmed, Embase, the China National Knowledge Infrastructure and the Wanfang Database were searched for articles published up to May 26th, 2013 that addressed eNOS-4b/a polymorphism and the risk of DN among type 2 diabetic subjects. 18 studies were included in this meta-analysis. eNOS-4b/a polymorphisms were associated with an overall significantly increased risk of DN (allele model: OR = 1.44, 95% CI = 1.14-1.82; additive model: OR = 2.03, 95% CI = 1.14-3.62; dominant model: OR = 1.34, 95% CI = 1.07-1.68; recessive model: OR = 2.01, 95% CI = 1.12-3.61). Subgroup analysis revealed a significant association between the eNOS-4b/a polymorphism and DN in Asian population, especially in Chinese population, but not in non Asian populations. Our meta-analysis supported an association between the 4b/a polymorphism of eNOS gene and increased risk of DN in type 2 diabetes among Asians, especially in Chinese population.

Genetics of diabetes complications

Chronic hyperglycemia and duration of diabetes are the major risk factors associated with development of micro- and macrovascular complications of diabetes. Although it is believed that hyperglycemia induces damage to the particular cell subtypes, e.g., mesangial cells in the renal glomerulus, capillary endothelial cells in the retina, and neurons and Schwann cells in peripheral nerves, the exact mechanisms underlying these damaging defects are not yet well understood. Clustering of micro- and macrovascular complications in families of patients with diabetes suggests a strong genetic susceptibility. However, until now only a handful number of genetic variants were reported to be associated with either nephropathy (ACE, ELMO1, FRMD3, and AKR1B1) or retinopathy (VEGF, AKR1B1, and EPO), and only a few studies were carried out for genetic susceptibility to cardiovascular diseases (ADIPOQ, GLUL) in patients with diabetes. It is, therefore, obvious that the accumulation of more data from larger studies and better phenotypically characterized cohorts is needed to facilitate genetic discoveries and unravel novel insights into the pathogenesis of diabetic complications.

ACE insertion/deletion polymorphism and diabetic nephropathy: clinical implications of genetic information

Approximately 20-40% of diabetic patients develop nephropathy which is the leading cause of ESRD in developed countries. The ACE I/D polymorphism is thought to be a marker for functional polymorphism which regulates circulating and tissue ACE activity. While the initial study found a protective effect of the II genotype on the development of nephropathy in IDDM patients, subsequent studies have addressed the role of ACE I/D polymorphism in the development and progression of diabetic nephropathy. RAAS blockers are the first line drugs for the treatment hypertension associated with diabetes and have been widely used in everyday clinical practice for the purpose of reducing proteinuria in patients with various renal diseases. However, the antiproteinuric effect of RAAS blockers is variable and the percentage of reducing proteinuria is in the range of 20-80%. The antiproteinuric effect of RAAS blockers may be related to a number of factors: the type or the dose of RAAS blockers, the duration of therapy, the level of sodium intake, and the type of patient's ACE I/D genotype. Besides the nongenetic factors, drug responses, can be influenced by ACE gene polymorphism. In this review, we discuss the relationship between ACE I/D polymorphism and diabetic nephropathy and therapeutic response of RAAS blockers.