Combined effects of cigarette smoking, alcohol drinking and eNOS Glu298Asp polymorphism on blood pressure in Chinese male hypertensive subjects

Genetic Polymorphisms of Endothelial Nitric Oxide Synthase Associated with Hypertension and Blood Homocysteine Levels

Purpose

Endothelial dysfunction is a key mechanism in the development of hypertension and is closely linked to impairment of endothelial nitric oxide synthase (eNOS) and hyperhomocysteinemia. Genetic polymorphisms of eNOS (rs1799983 and rs2070744) are strongly associated with the risk of hypertension in individuals of Asian ethnicities. This study aimed to investigate the relationship between these polymorphisms and the risk of hypertension associated with homocysteine levels.

Participants and Methods

For this cross-sectional study, we enrolled 370 Thai men aged 40-60 years from the Electricity Generating Authority of Thailand cohort study for both variants genotyping by TaqMan allelic discrimination analysis. Clinical, anthropometric, and biochemical parameters were also analyzed.

Results

In the high blood pressure group (n = 267), systolic and diastolic blood pressure and triglyceride levels were higher in those with homocysteine levels ≥ 15 µmol/L than in those with homocysteine levels < 15 µmol/L (p < 0.05). Significant risk of hypertension was found in GG and GT of rs1799983 (G894T), and in TT and TC of rs2070744 (T-786C), with higher ORs in heterozygous genotypes (all p values < 0.05). Further evaluation of the interactions between SNPs and HCY revealed that individuals with the GT or TC genotype, together with hyperhomocysteinemia, had an increased risk of hypertension (all p<0.05).

Conclusion

eNOS variants rs1799983 and rs2070744 may be risk factors for hypertension linked to hyperhomocysteinemia. These findings provide potentially useful healthcare strategies for the management of hypertension.

Association between living arrangements and health risk behaviors among the Hakka older adults in Fujian, China

BACKGROUND

Behavioral lifestyles are important social determinants of health. The impact of changes in living arrangements on behavioral lifestyles is currently under-explored. This study aims to examine the association between living arrangements and health risk behaviors among the Hakka older adults.

METHODS

Data were extracted from China's Health-Related Quality of Life Survey for Older Adults 2018. Living arrangements were divided into five categories: living alone, living with spouse only, living with child, mixed habitation, and others. Five health risk behaviors, including unhealthy dietary patterns, drinking, smoking, irregular sleep practices, and physical inactivity were measured. Logistic regression analysis was used to assess the association between living arrangements and specific health risk behaviors, and generalized linear models were established to test the association between living arrangements and the number of health risk behaviors.

RESULTS

A total of 1,262 Hakka older adults were included in this study. Compared to those living alone, those living with spouse only were less likely to have unhealthy dietary patterns (OR = 0.45, P < 0.05) and drinking (OR = 0.50, P < 0.05), those living with the child were less likely to experience unhealthy dietary patterns (OR = 0.35, P < 0.001), drinking (OR = 0.32, P < 0.001), smoking (OR = 0.49, P < 0.05), and physical inactivity (OR = 0.13, P < 0.01). Moreover, those who were living with child (β = -0.78, P < 0.001) or mixed habitation (β = -0.33, P < 0.05) tended to engage in fewer health risk behaviors than those living alone.

CONCLUSIONS

This study suggests significant differences in health risk behaviors among the Hakka older adults with different living arrangements. Living with the child could reduce the occurrence of health risk behaviors in the Hakka older adults and thus maintain their health status.

Live to die another day: novel insights may explain the pathophysiology behind smoker's paradox in SARS-CoV-2 infection

The severe acute respiratory coronavirus 2 (SARS-CoV-2) infection demonstrates a highly variable and unpredictable course. Several reports have claimed a smoker's paradox in coronavirus disease 2019 (COVID-19), in line with previous suggestions that smoking is associated with better survival after acute myocardial infarction and appears protective in preeclampsia. Several plausible physiological explanations exist accounting for the paradoxical observation of smoking engendering protection against SARS-CoV-2 infection. In this review, we delineate novel mechanisms whereby smoking habits and smokers' genetic polymorphism status affecting various nitric oxide (NO) pathways (endothelial NO synthase, cytochrome P450 (CYP450), erythropoietin receptor (EPOR); β-common receptor (βcR)), along with tobacco smoke modulation of microRNA-155 and aryl-hydrocarbon receptor (AHR) effects, may be important determinators of SARS-CoV-2 infection and COVID-19 course. While transient NO bioavailability increase and beneficial immunoregulatory modulations through the above-mentioned pathways using exogenous, endogenous, genetic and/or therapeutic modalities may have direct and specific, viricidal SARS-CoV-2 effects, employing tobacco smoke inhalation to achieve protection equals self-harm. Tobacco smoking remains the leading cause of death, illness, and impoverishment.

The Relationship Between eNOS Polymorphisms With Age, Smoking, Body Mass Index, and Clinicopathologic Parameters in Patients With Breast Cancer in Comparison With a Control Group

INTRODUCTION

Nitric oxide (NO) is a free radical involved in carcinogenesis and is synthesized by endothelial nitric oxide synthase (eNOS). Genetic changes in the eNOS enzyme affect its activity, and the nitric oxide produced by inhibiting apoptosis can lead to cancer cell proliferation and metastasis. In this study, in addition to investigating the relationship between genetic changes in eNOS gene and the risk of breast cancer, the relationship between genotypes of polymorphisms, age, smoking, body mass index, and clinopathologic parameters was also investigated.

MATERIAL AND METHODS

Three functional (Intron 4a/b, T786C, and G894T) and 1 tagging (G10T) polymorphisms of the eNOS gene were examined in 203 patients with breast cancer and 203 control subjects, and their genotypes were identified by restriction fragment length polymorphism polymerase chain reaction.

RESULTS

The T allele in G10T polymorphism increased the risk of breast cancer by 1.503-fold, whereas allele a in Intron 4, T allele in G894T, and C allele in T786C decreased its risk by 0.678-, 0.440-, and 0.525-fold, respectively. GG, GT (G10T), bb and ab (Intron4), GG and TT (G894T), and TT and CC (T786C) genotypes were significantly correlated with body mass index. There was a significant relationship between age and bb genotype, cigarette smoking and genotype ab (Intron 4), and estrogen receptor and GG (G10T) genotype. Tumor invasion factor was also significantly associated with TT (G10T), bb (Intron 4), and TT (T786C) genotypes.

CONCLUSION

Genetic changes in eNOS appear to have a dual role in breast cancer rate owing to changes in NO production and can be introduced as one of the genetic markers involved in breast cancer by evaluating the genotype of different populations.

Beneficial effects of nicotinamide on hypertensive mice with impaired endothelial nitric oxide function

Nicotinamide (Nam, amide form of niacin acid or nicotinate), a precursor for nicotinamide adenine dinucleotide (NAD+), is important for normal physiological function of organisms. Nam also suppresses mobilization of Ca²⁺ from sarcoplasmic reticulum into cytoplasm through inhibiting ADP-ribose cyclase. Previously, we have demonstrated that a pharmacological dose of Nam normalizes maternal blood pressure in mouse models of preeclampsia, a pregnancy related hypertensive disorder. We hypothesized that Nam could decrease blood pressure in hypertensive conditions unrelated to pregnancy. Nam at a dose of 500 mg/kg/day was given to wild type (WT) mice treated with L-NAME, endothelial nitric oxide synthase (eNOS)-null and renin transgenic (Renin-Tg) mice via drinking water. Blood pressure was measured by tail-cuff at different stages of treatment. The function and structure of kidneys of WT mice with L-NAME were determined at the end of the study. The gene expression of markers of inflammation and fibrosis in the kidneys of WT mice with L-NAME was also measured. Nam effectively prevented increase in blood pressure in L-NAME treated mice and decreased elevated blood pressure in eNOS-null mice. However, it did not alter high blood pressure in Renin-Tg mice. Nam prevented increase in urinary albumin excretion and collagen deposit in kidneys of WT mice treated with L-NAME. In addition, Nam significantly decreased the mRNA levels of the markers of inflammation and fibrosis in the kidneys of WT mice treated with L-NAME. Nam may execute beneficial effects on hypertensive conditions associated with eNOS dysfunction via suppressing inflammation. Because Nam is generally regarded as safe in humans, it merits further evaluation for the tailored treatment for the subgroup of hypertensive cases associated with impaired eNOS system.