Erythrocyte Na+/K(+)-ATPase and membrane and serum lipid profiles: as related to alcohol, body mass index and blood pressure

Meta-analytic evidence for a sex-diverging association between alcohol use and body mass index

Alcohol use is an important health issue and has been suggested to contribute to the burden produced by obesity. Both alcohol use and obesity are subject to sex differences. The available studies on the relationship between alcohol use and body mass index (BMI) report inconsistent results with positive, negative, and null findings which requests a meta-analytic approach. Therefore, we conducted a meta-analysis of case-control, cohort, and cross-sectional studies. The systematic literature search and data extraction was performed by 3 independent raters. We conducted sex-separated meta-analyses and -regressions to investigate how alcohol consumption associates with BMI. Our systematic literature search resulted in 36 studies with 48 data sets (N_men = 172,254; k_men = 30; N_women = 24,164; k_women = 18; N_{unknown sex} = 672,344; k_{unknown sex} = 24). Alcohol use was associated with higher BMI in men (g = 0.08 [0.07; 0.09]) and lower BMI in women (g = - 0.26 [- 0.29; - 0.22]). Moreover, we found the amount of daily alcohol intake in men (β = 0.001 [0.0008; 0.0014]) and ethnicity in women (g[Caucasians] = - 0.45 versus g[Asians] = - 0.05; z = 11.5, p < 0.0001) to moderate these effects. We here identified sex-diverging relationships between alcohol use and BMI, found daily alcohol intake and ethnicity to sex-specifically moderate these effects, and argue that sex-specific choice of beverage type and higher amount of daily alcohol use in men than in women account for these observations. Future research is needed to provide empirical evidence for the underlying mechanisms.

Alterations in erythrocyte membrane fluidity and Na+/K+ -ATPase activity in chronic alcoholics

Ethanol disorders biological membranes causing perturbations in the bilayer and also by altering the physicochemical properties of membrane lipids. But, chronic alcohol consumption also increases nitric oxide (NO) production. There was no systemic study was done related to alcohol-induced production of NO and consequent formation of peroxynitrite mediated changes in biophysical and biochemical properties, structure, composition, integrity and function of erythrocyte membranes in chronic alcoholics. Hence, keeping all these conditions in mind the present study was undertaken to investigate the role of over produced nitric oxide on red cell membrane physicochemical properties in chronic alcoholics. Human male volunteers aged 44 +/- 6 years with similar dietary habits were divided into two groups, namely nonalcoholic controls and chronic alcoholics (~125 g of alcohol at least five times per week for the past 10-12 years). Elevated nitrite and nitrate levels in plasma and lysate, changes in erythrocyte membrane individual phospholipid composition, increased lipid peroxidation, protein carbonyls, cholesterol and phospholipids ratio (C/P ratio) and anisotropic value (gamma) with decreased sulfhydryl groups and Na(+)/K(+)-ATPase activity in alcoholics was evident from this study. RBC lysate NO was positively correlated with C/P ratio (r = 0.547) and anisotropic (gamma) value (r = 0.428), Na(+)/K(+)-ATPase activity was negatively correlated with RBC lysate NO (r = -0.372) and anisotropic (gamma) value (r = -0.624) in alcoholics. Alcohol-induced overproduction of nitric oxide reacts with superoxide radicals to produce peroxynitrite, which appears to be responsible for changes in erythrocyte membrane lipids and the activity of Na(+)/K(+)-ATPase.

Inhibition of human erythrocyte (Na(+)-K+)ATPase by organic hydroperoxides and protection by ascorbic acid and butylated hydroxytoluene

1. The in vitro effects of cumene hydroperoxide and t-butyl hydroperoxide on intact human erythrocyte membrane (Na(+)-K+)ATPase activities have been studied. 2. (Na(+)-K+)ATPase activities on erythrocyte membranes decreased in agreement with the results of chemiluminescence experiments. 3. Our results demonstrated that the organic hydroperoxides inhibit the activity of (Na(+)-K+) ATPase enzyme and that the antioxidants used prevent this inhibition.

Plasma triglycerides and red cell ion transport alterations in genetically hypertensive rats

Ion transport abnormalities in essential hypertension are often associated with concomitant changes of lipid metabolism, but this information is missing in rats with genetic hypertension. We therefore studied the alterations of red cell Na+ and K+ transport and their relationship to blood pressure and plasma lipids (cholesterol and triglycerides) in Prague hereditary hypertriglyceridemic (HTG) rats, Lyon hypertensive (LH) rats, and HTG x Lewis F2 hybrids. In both hypertensive models and F2 hybrids, red cell Na+ content (Na+(i)) was positively related to plasma triglycerides but not to plasma cholesterol levels. Na+(i) elevation was more pronounced in HTG than in LH rats, probably due to higher plasma triglycerides in the former strain. The two hypertensive strains differed in bumetanide-sensitive Na+ transport, which was augmented in HTG rats with low plasma cholesterol but suppressed in LH rats characterized by high cholesterol levels. In the two genetic models, there was a positive association of blood pressure with Na+ leak, and this was also confirmed by the cosegregation of these parameters in F2 hybrids. We conclude that the enhancement of Na+ leak represents the major ion transport abnormality in rats with genetic hypertension. The alterations in plasma lipids are important determinants of abnormal red cell ion transport in hypertensive models studied. Although the detailed mechanism of their participation in ion transport regulation is still not completely understood, triglyceride-dependent changes in membrane microviscosity seem to be responsible for the modulation of particular ion transport pathways.

Serum gamma-glutamyl transferase levels and blood pressure falls after alcohol moderation

Drinkers showing higher serum gamma-glutamyl transferase (GGT) levels tend to have higher blood pressure (BP), independent of the volume of alcohol consumed. To further evaluate the link between alcohol consumption and elevated serum GGT and BP, we observed BP, serum biochemical parameters, plasma pressor hormones and intraplatelet free calcium (Plt. [Ca2+]i) in 40 moderate drinkers who were composed of four categories of 10 each with or without hypertension (> or = 140/90 mmHg) or high serum GGT level (> or = 50 U/L) during four-week alcohol moderation. BP and serum hepatic enzymes including GGT decreased more conspicuously in both normotensive and hypertensive drinkers with high serum GGT. Serum triglyceride was higher and potassium was lower in the drinkers with high serum GGT, and were normalized during alcohol moderation. Serum calcium, Plt. [Ca2+]i and plasma renin activity and cortisol showed some decreases during alcohol moderation, but were not different in the drinkers with different serum GGT and BP levels. No significant changes were observed in plasma catecholamines and aldosterone. These results suggest that BP elevations in moderate drinkers are closely related to hepatic, lipid and electrolyte metabolic alterations induced by alcohol rather than specific pressor agents.