The 27-bp repeat polymorphism in intron 4 (27 bp-VNTR) of endothelial nitric oxide synthase (eNOS) gene is associated with albumin to creatinine ratio in Mexican Americans

Inside the genome: understanding genetic influences on oxidative stress

Genetics is a key factor that governs the susceptibility to oxidative stress. In the body, oxidative burden is regulated by the balance between the prooxidant genes that orchestrate processes that produce oxidant species, while the antioxidant genes aid those involved in scavenging these species. Together, the two components aid in maintaining the oxidative balance in the body. Genetic variations can influence the expression and activity of the encoded proteins which can then affect their efficiency in regulating redox processes, thereby increasing the risk of oxidative stress. This review studies single nucleotide polymorphisms (SNPs) that bear relevance to oxidative stress by exploring the variations in the prooxidant genes, such as XDH, CYBA, CYP1A1, PTGS2, NOS, and MAO and antioxidant genes including SOD, CAT, GPX, GSS, GLUL, GSR, GSTM1, GSTM5, GSTP1, TXN and HMOX1. Early identification of individuals at the increased risk of oxidative stress is possible from the assessment of sequence of these genes. Integrating genetic insights into oxidative stress management measures can pave the way for personalized medicine that tailors' healthcare approaches to individual genetic profiles. Effective genetic assessment along with routine quantification of biological markers can improve and monitor treatment strategies, enhancing mitigation approaches that maintain cellular health and promote longevity.

Association between the Polymorphisms rs2070744, 4b/a and rs1799983 of the NOS3 Gene with Chronic Kidney Disease of Uncertain or Non-Traditional Etiology in Mexican Patients

Background and Objectives: Chronic Kidney Disease of uncertain or non-traditional etiology (CKDnT) is a form of chronic kidney disease of undetermined etiology (CKDu) and is not associated with traditional risk factors. The aim of this study was to investigate the association of polymorphisms rs2070744, 4b/a and rs1799983 of the NOS3 gene with CKDnT in Mexican patients. Materials and Methods: We included 105 patients with CKDnT and 90 controls. Genotyping was performed by PCR-RFLP's, genotypic and allelic frequencies were determined and compared between the two groups using χ2 analysis, and differences were expressed as odd ratios with 95% confidence intervals (CI). Values of p < 0.05 were considered statistically significant. Results: Overall, 80% of patients were male. The rs1799983 polymorphism in NOS3 was found to be associated with CKDnT in the Mexican population (p = 0.006) (OR = 0.397; 95% CI, 0.192-0.817) under a dominant model. The genotype frequency was significantly different between the CKDnT and control groups (χ2 = 8.298, p = 0.016). Conclusions: The results of this study indicate that there is an association between the rs2070744 polymorphism and CKDnT in the Mexican population. This polymorphism can play an important role in the pathophysiology of CKDnT whenever there is previous endothelial dysfunction.

Association of Endothelial Nitric Oxide Synthase 894G > T Polymorphism with Preeclampsia Risk: A Systematic Review and Meta-Analysis based on 35 Studies

Several case-control studies have been performed to investigate the association between 894 G > T polymorphism in endothelial nitric oxide synthase (eNOS) gene and susceptibility to preeclampsia. However, the results were inconsistent and inconclusive. Therefore, we conducted this meta-analysis to investigate the association. Methods: All studies published up to September 30, 2019 were identified by searching electronic databases such as PubMed, EMBASE, CNKI, and WANFANG. Results: A total of 35 case- control studies with 4,254 cases and 5,801 controls were selected. There was a significant association between the eNOS 894 G > T and preeclampsia risk. When stratified by ethnicity, an increased risk of preeclampsia was found in Caucasian and Mixed populations, but not in Asians or Africans. Conclusion: Based on our meta-analysis, the eNOS 894 G > T polymorphism was associated with an increased risk of preeclampsia, especially among Caucasian and Mixed populations.

Understanding the growing epidemic of type 2 diabetes in the Hispanic population living in the United States

The prevalence and incidence of type 2 diabetes (T2D) among the Hispanic population in the United States are higher than the national average. This is partly due to sociocultural factors, such as lower income and decreased access to education and health care, as well as a genetic susceptibility to obesity and higher insulin resistance. This review focuses on understanding the Hispanic population living in the United States from a multidisciplinary approach and underlines the importance of cultural, social, and biological factors in determining the increased risk of T2D in this population. An overview of the acute and chronic complications of T2D upon this population is included, which is of paramount importance to understand the toll that diabetes has upon this population, the health system, and society as a whole. Specific interventions directed to the Hispanic populations are needed to prevent and alleviate some of the burdens of T2D. Different prevention strategies based on medications, lifestyle modifications, and educational programmes are discussed herein. Diabetes self-management education (DSME) is a critical element of care of all people with diabetes and is considered necessary to improve patient outcomes. To be more effective, programmes should take into consideration cultural factors that influence the development and progression of diabetes. These interventions aim to enhance long-term effects by reducing the incidence, morbidity, and mortality of T2D in the Hispanic population of the United States.

Association between NOS3 G894T, T-786C and 4a/4b Variants and Coronary Artery Diseases in Iranian Population

BACKGROUND

Endothelial nitric oxide synthase, encoded by NOS3, produces an atheroprotective metabolite. The G894T, T-786C and 4a/4b variants of this gene associated with increased risk for coronary artery diseases (CAD) have been evaluated in different populations worldwide, and inconsistent results have been obtained. We investigated the association between these three polymorphisms and presence of CAD in Iranian individuals.

METHODS

Overall, 234 people including angiography-positive patients from Amir-Almomenin Hospital (Heart Center), Kordkoy City, Golestan Province, northern Iran in 2016, angiography-negative subjects and healthy individuals from north of Iran were genotyped for the G894T and T-786C variations by PCR-RFLP, and 4a/4b VNTR only by PCR.

RESULTS

The genotype distribution and allelic frequencies for the three variants tested were not dramatically different between CAD and control subjects and also between CAD patients and people with pains and symptoms very similar to CAD but no stenosis (P>0.05). Moreover, the odds ratio for CAD related to the G894T (OR=1.09, 95% CI=(0.60-2.00), T-786C (OR=1.04, 95% CI=(0.57-1.89) and 4a/4b (OR=1.75, 95% CI=(0.92-3.32) variants did not show statistical significance. Similarly, the odds ratio for stenosis confirmed by angiography related to the 894T (OR=1.03, 95% CI= (0.61-1.74), -786C (OR=0.90, 95% CI=(0.54-1.50) and 4b (OR=1.64, 95% CI=(0.92 -2.93) alleles were not significant.

CONCLUSION

G894T, T-786C and 4a/4b variants were not associated with risk for CAD and occurrence of angiography-assessed stenosis in Northern Iranian population (P>0.05). These alleles might be population-specific and not to be associated with their corresponding gene pool. However, further analysis is required to clarify other CAD-correlated markers in our community.

Endothelial nitric oxide synthase polymorphisms and susceptibility to high-tension primary open-angle glaucoma in an Egyptian cohort

PURPOSE

To analyze the association of polymorphisms of the endothelial nitric oxide synthase (NOS3) gene and nitric oxide (NO) levels with high-tension primary open-angle glaucoma (POAG) in an Egyptian population.

METHODS

This case-control study included 160 patients who had high-tension POAG (76 men and 84 women; age range 41-75 years) and 110 controls (56 men and 54 women; age range 55-78 years). Genotyping of T-786C (rs2070744), Glu298Asp (rs1799983), and the 27-bp insertional variable number tandem repeat (VNTR) in intron 4 of the NOS3 gene was performed with an amplification refractory mutation system PCR assay. The NO level was determined by measuring the total nitrate/nitrite (NOX) plasma level.

RESULTS

The CC genotype of the T-786C polymorphism was significantly associated with POAG (odds ratio [OR] = 2.54, 95% confidence interval [CI] = 1.26-5.13, p = 0.007). The C allele was significantly associated with POAG (OR = 1.86, 95% CI = 1.29-2.69, p<0.001). After stratification by sex, the CC genotype and the C allele were significantly associated with POAG in women only (OR = 3.06, 95% CI = 1.07-8.74, p = 0.03 for the CC genotype, and OR = 2.09, 95% CI = 1.24-3.53, p = 0.005 for the C allele). The genotype and allele frequencies of Glu298Asp and intron 4 were not significant between the patients with POAG and the controls, and after stratification by sex. The mean NOX plasma level was significantly lower in patients with POAG than in the controls (p = 0.01) and low in the (TC+CC) genotype compared to the TT genotype of T-786C in the patients and controls (p<0.001).

CONCLUSIONS

The results suggest that the CC genotype of T-786C NOS3 may be associated with an increased risk of developing high-tension POAG in Egyptians, particularly women. In addition, decreased NO levels may play a role in the development of POAG.

Susceptibility gene search for nephropathy and related traits in Mexican-Americans

The rising global epidemic of diabetic nephropathy (DN) will likely lead to increase in the prevalence of cardiovascular morbidity and mortality posing a serious burden for public health care. Despite greater understanding of the etiology of diabetes and the development of novel treatment strategies to control blood glucose levels, the prevalence and incidence rate of DN is increasing especially in minority populations including Mexican-Americans. Mexican-Americans with type 2 diabetes (T2DM) are three times more likely to develop microalbuminuria, and four times more likely to develop clinical proteinuria compared to non-Hispanic whites. Furthermore, Mexican-Americans have a sixfold increased risk of developing renal failure secondary to T2DM compared to Caucasians. Prevention and better treatment of DN should be a high priority for both health-care organizations and society at large. Pathogenesis of DN is multi-factorial. Familial clustering of DN-related traits in MAs show that DN and related traits are heritable and that genes play a susceptibility role. While, there has been some progress in identifying genes which when mutated influence an individual's risk, major gene(s) responsible for DN are yet to be identified. Knowledge of the genetic causes of DN is essential for elucidation of its mechanisms, and for adequate classification, prognosis, and treatment. Self-identification and collaboration among researchers with suitable genomic and clinical data for meta-analyses in Mexican-Americans is critical for progress in replicating/identifying DN risk genes in this population. This paper reviews the approaches and recent efforts made to identify genetic variants contributing to risk for DN and related phenotypes in the Mexican-American population.

Association of eNOS gene intron 4 a/b VNTR polymorphisms in children with nephrotic syndrome

To investigate the association of endothelial nitric oxide synthase gene intron 4 (eNOS4) polymorphisms with nephrotic syndrome, the eNOS4 genotypes were assessed in 161 children with nephrotic syndrome in comparison with 78 healthy subjects. We classified the children with nephritic syndrome into 2 groups: as steroid-sensitive nephrotic syndrome (SSNS) (n=125) and steroid-resistant nephrotic syndrome (SRNS) (n=36). The eNOS4 polymorphisms were analyzed by polymerase chain reaction. The frequencies of eNOS4 aa, ab and bb genotypes were 3%, 31%, and 66% in all the nephrotic syndrome groups, and 1%, 23%, and 76% in the control group (x(2)=2.87, p>0.05). In addition, the frequencies of eNOS4 aa, ab and bb genotypes were 2%, 33%, and 65% in SSNS group, and 5%, 28%, and 67% in the SRNS group (x(2)=1.13, p=0.567). The present study is the first to investigate eNOS4 gene polymorphisms in children with SSNS and SRNS. Our data show that the eNOS4 gene polymorphisms were not associated with the development, frequent relapse and response to steroid in nephritic syndrome.

Inflammation gene variants and susceptibility to albuminuria in the U.S. population: analysis in the Third National Health and Nutrition Examination Survey (NHANES III), 1991-1994

BACKGROUND

Albuminuria, a common marker of kidney damage, serves as an important predictive factor for the progression of kidney disease and for the development of cardiovascular disease. While the underlying etiology is unclear, chronic, low-grade inflammation is a suspected key factor. Genetic variants within genes involved in inflammatory processes may, therefore, contribute to the development of albuminuria.

METHODS

We evaluated 60 polymorphisms within 27 inflammatory response genes in participants from the second phase (1991-1994) of the Third National Health and Nutrition Examination Survey (NHANES III), a population-based and nationally representative survey of the United States. Albuminuria was evaluated as logarithm-transformed albumin-to-creatinine ratio (ACR), as ACR ≥ 30 mg/g, and as ACR above sex-specific thresholds. Multivariable linear regression and haplotype trend analyses were conducted to test for genetic associations in 5321 participants aged 20 years or older. Differences in allele and genotype distributions among non-Hispanic whites, non-Hispanic blacks, and Mexican Americans were tested in additive and codominant genetic models.

RESULTS

Variants in several genes were found to be marginally associated (uncorrected P value < 0.05) with log(ACR) in at least one race/ethnic group, but none remained significant in crude or fully-adjusted models when correcting for the false-discovery rate (FDR). In analyses of sex-specific albuminuria, IL1B (rs1143623) among Mexican Americans remained significantly associated with increased odds, while IL1B (rs1143623), CRP (rs1800947) and NOS3 (rs2070744) were significantly associated with ACR ≥ 30 mg/g in this population (additive models, FDR-P < 0.05). In contrast, no variants were found to be associated with albuminuria among non-Hispanic blacks after adjustment for multiple testing. The only variant among non-Hispanic whites significantly associated with any outcome was TNF rs1800750, which failed the test for Hardy-Weinberg proportions in this population. Haplotypes within MBL2, CRP, ADRB2, IL4R, NOS3, and VDR were significantly associated (FDR-P < 0.05) with log(ACR) or albuminuria in at least one race/ethnic group.

CONCLUSIONS

Our findings suggest a small role for genetic variation within inflammation-related genes to the susceptibility to albuminuria. Additional studies are needed to further assess whether genetic variation in these, and untested, inflammation genes alter the susceptibility to kidney damage.

Association of eNOS and HSP70 gene polymorphisms with glaucoma in Pakistani cohorts

PURPOSE

To investigate the involvement of stress-regulating genes, endothelial nitric oxide synthase (eNOS) and heat shock protein 70 (HSP70) with primary open angle glaucoma (POAG) and primary closed angle glaucoma (PCAG).

METHODS

POAG and PCAG patients recruited from different areas of Pakistan were diagnosed on the basis of clinical history, raised intraocular pressure (IOP), cup-to-disc ratio (CDR) and visual field defects. Their blood was collected and genomic DNA was extracted from it, followed by PCR amplification and VNTR typing of the eNOS gene, while the HSP70 SNP was analyzed with PCR-RFLP. For both of the polymorphisms, the genotype distribution of the POAG and PCAG patients was compared with unaffected controls.

RESULTS

HSP70 polymorphism was found to be significantly associated with PCAG (chi(2)=15.29 [p<0.001], OR=2.63 [95% CI=1.55-4.48]), with p<0.001 for the dominant model and OR=2.09 (95% CI=1.10-3.96) , with p<0.01 for the recessive model, but not with POAG (chi(2)=2.96 [p>0.05]). As opposed to this significant eNOS association, was seen with PCAG (chi(2)=6.33 [p<0.05], OR=2.09 [95% CI=1.12-3.89]), with p<0.01 for the dominant model, as well as with POAG (chi(2)=8.89 [p<0.05], OR=2.23 [95% CI=1.26-3.39]), with p<0.01 for dominant model. For the eNOS case, we found a significant association with the risk allele "a" for POAG patients (chi(2)=9.29 [p<0.01], OR=2.02 [95% CI=1.25-3.28, p=0.001]) and PCAG patients (chi(2)=7.59 [p<0.01], OR=1.99 [95% CI=1.18-3.37, p<0.01]). Similarly, in the HSP70 case, there was a significant association with the risk allele "C" for POAG patients (chi(2)=3.57 [p=0.05], OR=1.38 [95% CI=0.97-1.94, p<0.05]) and PCAG patients (chi(2)=18.32 (p<0.001), OR=2.16 [95% CI=1.49-3.13, p<0.001]).

CONCLUSIONS

The intron 4 polymorphism of eNOS is associated with POAG, as well as PCAG, while the G+190C polymorphism in HSP70 is associated with PCAG, but not with POAG in the Pakistani population.

A meta-analysis of three polymorphisms in the endothelial nitric oxide synthase gene (NOS3) and their effect on the risk of diabetic nephropathy

A number of association studies have investigated the role of the nitric oxide synthase 3 (NOS3) gene in the development of diabetic nephropathy (DN). However, results have been inconclusive, largely because the studies have focused on a variety of different polymorphisms and generate inconsistent results. We performed a meta-analysis of 28 association studies focusing on three polymorphisms in the NOS3 gene (G894T (Glu289Asp), 4b/a, and T-786C) and the risk of DN published before July 2009, covering a total of 10,364 subjects. Although significant heterogeneity was initially found in the analysis of G894T, it did not remain when analysis was done by ethnic subgroups. 894T was negatively associated with DN in Caucasian populations of European origin (OR = 0.896, 0.817-0.983, 95% CI), but was positively associated with DN in East Asian (OR = 2.02, 1.20-3.42, 95% CI) and other populations. Association of the 4b/a variant was observed when studies involving microalbuminuria were excluded (OR = 1.19, 1.02-1.39, 95% CI). The T-786C variant showed an overall weak association (OR = 1.16, 1.01-1.34, 95% CI) with little heterogeneity. In summary, our meta-analysis of the effect of NOS3 gene polymorphisms on the risk of DN supports the involvement of the NOS3 gene in the pathogenesis of DN.