Variants of endothelial nitric oxide synthase gene are associated with components of metabolic syndrome in an Arab population

Endothelial nitric oxide synthase gene polymorphism (786T/C) in childhood acute lymphoblastic leukemia survivors

OBJECTIVES

To detect eNOS gene polymorphism and its relation to cardiovascular complications in pediatric acute lymphoblastic leukemia (ALL) survivors.

METHODS

CBC, renal and liver function tests, lipid profile, Carotid artery Intima Media Thickness (CIMT), and Brachial artery Intima Media Thickness (BIMT). eNOS gene polymorphism was done in 40 childhood ALL survivors and 40 controls.

RESULTS

There was no significant difference between survivors and control groups regarding 786 T/C polymorphism. There was a significant increase in serum cholesterol, TGs, LDL, VLDL, and HbA1c in the TC and CC group more than in the TT group, while there was a significant decrease in serum HDL in the TC and CC group more than in the TT group. There was no significant difference as regards echocardiography findings between different polymorphisms of 786 T/C, but there was a significant difference between 786 T/C groups with regard to the carotid and brachial arteries intima media thickness (IMT) measurements being significantly higher in the TC and CC group more than in the TT group.

CONCLUSION

Carotid and brachial arteries intima media thickness measurements were higher in the survivors when compared to healthy controls. eNOS gene polymorphism may play a role in modifying or developing CVD in pediatric ALL survivors.

Does eNOS derived nitric oxide protect the young from severe COVID-19 complications?

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Aging is the largest risk factors for severity and mortality in adult COVID-19.

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Severe cases of COVID-19 are related to vascular damage with evidence of direct viral infection in the endothelial cells.

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Increase risk of COVID-19 death are also highly related to disease with lower vascular Nitric Oxide (NO) level.

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Vascular viral defence by endothelial nitric oxide synthase (eNOS) derive NO may be the protecting factor for the young.

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eNOS polymorphism could potentially explain the disparity of COVID-19 mortality between Asian and non-Asian countries.

The COVID-19 pandemic poses an imminent threat to humanity, especially to the elderly. The molecular mechanisms underpinning the age-dependent disparity for disease progression is not clear. COVID-19 is both a respiratory and a vascular disease in severe patients. The damage endothelial system provides a good explanation for the various complications seen in COVID-19 patients. These observations lead us to suspect that endothelial cells are a barrier that must be breached before progression to severe disease. Endothelial intracellular defences are largely dependent of the activation of the interferon (IFN) system. Nevertheless, low type I and III IFNs are generally observed in COVID-19 patients suggesting that other intracellular viral defence systems are also activated to protect the young. Intriguingly, Nitric oxide (NO), which is the main intracellular antiviral defence, has been shown to inhibit a wide array of viruses, including SARS-CoV-1. Additionally, the increased risk of death with diseases that have underlying endothelial dysfunction suggest that endothelial NOS-derived nitric oxide could be the main defence mechanism. NO decreases dramatically in the elderly, the hyperglycaemic and the patients with low levels of vitamin D. However, eNOS derived NO occurs at low levels, unless it is during inflammation and co-stimulated by bradykinin. Regrettably, the bradykinin-induced vasodilation also progressively declines with age, thereby decreasing anti-viral NO production as well. Intriguingly, the inverse correlation between the percentage of WT eNOS haplotype and death per 100K population could potentially explain the disparity of COVID-19 mortality between Asian and non-Asian countries. These changes with age, low bradykinin and NO, may be the fundamental reasons that intracellular innate immunity declines with age leading to more severe COVID-19 complications.

Genetic Variants of the PLCXD3 Gene Are Associated with Risk of Metabolic Syndrome in the Emirati Population

Phosphatidylinositol-specific phospholipase C X domain 3 (PLCXD3) has been shown to influence pancreatic β-cell function by disrupting insulin signaling. Herein, we investigated two genetic variants in the PLCXD3 gene in relation to type 2 diabetes (T2D) or metabolic syndrome (MetS) in the Emirati population. In total, 556 adult Emirati individuals (306 T2D and 256 controls) were genotyped for two PLCXD3 variants (rs319013 and rs9292806) using TaqMan genotyping assays. The frequency distribution of minor homozygous CC genotype of rs9292806 and GG genotype of rs319013 were significantly higher in subjects with MetS compared to Non-MetS (p < 0.01). The minor homozygous rs9292806-CC and rs319013-GG genotypes were significantly associated with increased risk of MetS (adj. OR 2.92; 95% CI 1.61–5.3; p < 0.001) (adj. OR 2.62; 95% CI 1.42–4.83; p = 0.002), respectively. However, no associations were detected with T2D. In healthy participants, the homozygous minor genotypes of both rs9292806 and rs319013 were significantly higher fasting glucose (adj. p < 0.005), HbA1c (adj. p < 0.005) and lower HDL-cholesterol (adj. p < 0.05) levels. Data from T2D Knowledge Portal database disclosed a nominal association of rs319013 and rs9292806 with T2D and components of MetS. Bioinformatics prediction analysis showed a deleterious effect of rs9292806 on the regulatory regions of PLCXD3. In conclusion, this study identifies rs319013 and rs9292806 variants of PLCXD3 as additional risk factors for MetS in the Emirati population.

Metabolic syndrome is negatively associated with cognition among endothelial nitric oxide synthase (eNOS)- 786C carriers in schizophrenia-spectrum disorders

Although metabolic syndrome and cognitive inefficiencies are well-described common complications of schizophrenia, their association remains inconsistent, potentially due to poorly understood mechanisms underlying their relationship. Variability in the endothelial nitric oxide synthase (eNOS) gene, specifically the T-786C variant, has been separately associated with cognition and metabolic syndrome, with worse outcomes for eNOS-786C carriers likely occurring via negative effects on blood vessel functioning. However, the interaction between eNOS and metabolic syndrome in cognition among adults with schizophrenia is unknown. This study aimed to test the main and interaction effects of the eNOS-786C allele in cognition using hierarchical regression analyses controlling for age, sex, education, race, and antipsychotic exposure. Metabolic syndrome, eNOS T-786C genotype, and cognitive performance were assessed in 226 community-dwelling participants with chronic schizophrenia-spectrum disorders. Results demonstrated a significant interaction between metabolic syndrome and the eNOS-786C allele. Specifically, among eNOS-786C carriers only, metabolic syndrome was independently associated with lower scores in processing speed and verbal fluency, and predicted 12.5% and 15.8% of variance in performance, respectively. These results suggest that the additive negative effects of eNOS-786C and metabolic syndrome on blood vessel functioning may be severe enough to negatively impact cognition. The finding that metabolic syndrome is associated with worse cognition only in the presence of the eNOS-786C allele may clarify extant inconsistencies in the literature. These findings provide preliminary evidence that may inform interventions to reduce cognitive morbidity among adults with schizophrenia.

Haplotype analysis of endothelial nitric oxide synthase (NOS3) genetic variants and metabolic syndrome in healthy subjects and schizophrenia patients

Background/objectives

The frequency of metabolic syndrome (MetS) is significantly higher in schizophrenia (SCH) patients, when compared to the general populatiotin. The goal of this study was to evaluate whether genetic variants T-786C (rs2070744), G894T (rs1799983) and C774T (rs1549758) in the endothelial nitric oxide (NOS3) gene and/or their haplotypes could be associated with the risk of MetS in SCH patients or healthy subjects from Russian population.

Subjects/methods

We performed two case−control comparisons. NOS3 polymorphisms were genotyped in 70 SCH patients with MetS, 190 normal weight SCH patients, 155 MetS patients, and 100 healthy controls. MetS was defined as per the criteria proposed by the International Diabetes Federation (IDF). Anthropometric, clinical, biochemical parameters, and serum nitrite concentrations were measured in all samples. Haplotype frequency estimations and linkage disequilibrium measures were made using Haploview 4.2.

Results

The higher C allele (P = 0.009) and lower TT genotype (P = 0.008) frequencies of T-786C polymorphism were found in SCH patients with MetS compared to those in normal weight SCH patients. SCH patients with MetS who were carriers of the T-786C TT genotype had lower serum total cholesterol levels in comparison to the CC genotype (P = 0.016). Furthermore, the 774T/894T haplotype was more frequent in non-SCH individuals with MetS compared to healthy controls (P = 0.0004, odds ratio = 2.18, 95% confidence interval 1.4–3.37). Conversely, the most common haplotype 774C/894G was less frequent in MetS patients than in healthy controls (P = 0.013, odds ratio = 0.61, 95% confidence interval 0.41–0.9).

Conclusions

These results indicate that the NOS3 T-786C promoter polymorphism was closely associated with MetS risk in SCH patients. In addition, the haplotypes composed of G894T and C774T polymorphisms are associated with the MetS susceptibility in Russian population.

Association of Glu298Asp Polymorphism of Endothelial NO Synthase Gene with Metabolic Syndrome Development: a Pilot Study

We studied association of single nucleotide polymorphism Glu298Asp (rs1799983) of the NOS3 gene with the risk of metabolic syndrome in the Slavic population. Blood samples were obtained from 128 patients with metabolic syndrome and 100 healthy individuals. Polymorphism Glu298Asp of the NOS3 gene was genotyped by allele-specific PCR. Allele Asp (OR=1.95, 95%CI 1.29-2.95, p=0.007) and genotype Asp/Asp (OR=2.56, 95%CI 0.98-6.72, p=0.04) were associated with the risk of metabolic syndrome in Slavic population. Patients with metabolic syndrome carrying genotype Asp/Asp had higher serum endothelin-1 level in comparison with Glu/Asp and Glu/Glu carriers.

Association of endothelial nitric oxide synthase (eNOS) gene G894T polymorphism with hypertension risk and complications

This study evaluated the association of NOS3 polymorphisms with hypertension risk and complications. eNOS (G894T) SNP was performed by RT-PCR on 70 hypertensive patients (25 were hypertensive, 25 were hypertensive with CAD, and 20 were diabetic with hypertension) and 30 age- and gender-matched individuals. Lipid and glucose profile were assessed by standard colorimetric assay. Our results revealed that combination of (GT + TT) genotype and T allele significantly increases the risk of hypertension (OR = 3.86 and 4.33), respectively. Subgroup analysis showed significant association between CAD with eNOS (G894T) mutant genotype (P = 0.002) and allele frequency (P < 0.001). Moreover, the mutant homozygous and heterozygous eNOS genotype together were significantly associated with higher TC, LDLc, (P < 0.001), and TG (P = 0.001). Thus, hypercholesterolemia (P < 0.001 and OR = 12.48) increases the risk of hypertension among T carrier. These results indicated that the T carriers significantly increase hypertension risk and complication (CAD), mainly with hypercholesterolemia and in elderly.

Gene-environment interactions in human health: case studies and strategies for developing new paradigms and research methodologies

THE SYNERGISTIC EFFECTS OF GENES AND THE ENVIRONMENT ON HEALTH ARE EXPLORED IN THREE CASE STUDIES: adult lactase persistence, autism spectrum disorders, and the metabolic syndrome, providing examples of the interactive complexities underlying these phenotypes. Since the phenotypes are the initial targets of evolutionary processes, understanding the specific environmental contexts of the genetic, epigenetic, and environmental changes associated with these phenotypes is essential in predicting their health implications. Robust databases must be developed on the local scale to deconstruct both the population substructure and the unique components of the environment that stimulate geographically specific changes in gene expression patterns. To produce these databases and make valid predictions, new, locally focused, and information-dense models are needed that incorporate data on evolutionary ecology, environmental complexity, local geographic patterns of gene expression, and population substructure.

Association of VDR-gene variants with factors related to the metabolic syndrome, type 2 diabetes and vitamin D deficiency

The prevalence of metabolic syndrome (MetS) is rising alarmingly in the Saudi Arabian population. This study was conducted to assess the association between vitamin D receptor (VDR) polymorphisms and genetic susceptibility to components of the metabolic syndrome, type 2 diabetes mellitus (T2DM), and vitamin D deficiency in the Saudi Arabian population. Five-hundred-seventy Saudi individuals (285 MetS and 285 controls) were enrolled in this cross-sectional study. TaqI, BsmI, ApaI and FokI single nucleotide polymorphisms (SNPs) of the VDR gene were genotyped. The CT genotype and allele T of BsmI were associated with lower HDL-C levels [OR 0.60 (0.37, 0.96), p=0.03] and obesity [OR 1.4 (1.0, 1.90), p=0.04], respectively. The CT genotype and the dominant model CT+TT of BsmI were associated with increased risk of diabetes [OR 1.7 (1.2, 2.4), p=0.007], and [OR 1.5 (1.1, 2.2), p=0.01], respectively. On the contrary, the CT and CT+CC genotypes of FokI exhibited an association with a reduced risk of diabetes [OR 0.70 (0.49, 0.99), p=0.05] and [OR 0.67 (0.48, 0.94), p=0.02], respectively. The allele C of FokI was associated with lower risk of developing T2DM [OR 0.73 (0.56, 0.95), p=0.02]. The prevalence of vitamin D deficiency was lower in subjects with the AC genotype of ApaI [OR, 0.34 (0.14, 0.80), p=0.01]. Components of the MetS such as obesity, low HDL and T2DM were associated with the VDR gene. FokI and BsmI have protective and facilitative effects on the risk for T2DM, while the ApaI genotype was associated with reduced vitamin D deficiency.

eNOS polymorphism associated with metabolic syndrome in children and adolescents

We investigated whether genetic polymorphisms in the endothelial nitric oxide (eNOS) gene (T(786)C in the promoter region, Glu298Asp in exon 7, and 4b/4a in intron 4) or eNOS haplotypes are associated with metabolic syndrome (MetS) in obese children and adolescents. We studied 242 subjects: 108 healthy (controls), 64 normotensive obese, and 70 obese children and adolescents with MetS. Genotypes were determined by Taqman(®) allele discrimination assay and real-time polymerase chain reaction (PCR), and PCR followed by fragment separation by electrophoresis. We compared the distribution of eNOS genotypes, alleles, and haplotypes in the three groups of subjects. The CC genotype for the T(786)C polymorphism was more common in the MetS group than in the control group (OR = 3.27; CI 1.81-9.07; P < 0.05). However, we found no significant differences in the distribution of eNOS haplotypes (P > 0.00625; P for significance after correction for multiple comparisons). Our findings suggest that while eNOS haplotypes are not relevant, the CC genotype for the T(786)C polymorphism is associated with MetS in obese children and adolescents. Further studies examining interactions of eNOS haplotypes with environmental factors and other genetic markers are warranted.