G-protein β3-subunit gene variant, blood pressure and erythrocyte sodium/lithium countertransport in essential hypertension

Abstract

Recently, a C825T polymorphism in the gene coding for the beta3 subunit of G proteins (GNB3) has been described in cells from patients with essential hypertension and enhanced Na+/H+ exchange activity. This study aims to evaluate the association between the 825T allele and activity of erythrocyte sodium/lithium countertransport (Na+/Li+ CT) and other sodium transport systems in red blood cells from patients with essential hypertension. A group of 77 patients (36 male, 41 female; aged 51.7 +/- 1.1 years) was studied. The maximal rates (Vmax) of Na+/Li+ CT, Na+/K+/Cl- cotransport and Na+K+ ATPase were evaluated in erythrocytes from all the patients. They were genotyped for the C825T polymorphism by a polymerase chain reaction (PCR) method, followed by digestion with BseDI. Body mass index (BMI) was higher in CT+TT patients than in CC patients (28.9 +/- 0.5 vs. 27.0 +/- 0.7 kg/m2; P=0.023). Hypertensives with the T allele (CT+TT genotypes) showed significantly higher systolic blood pressure (BP) values (156.9 +/- 2.1 vs. 148.9 +/- 2.8 mmHg; P=0.024), whereas differences in diastolic BP did not reach statistical significance (96.4 +/- 1.0 vs. 94.0 +/- 1.1 mmHg; P=0.120). No differences in the Vmax of Na+/Li+ CT between the genotypes was seen (CC: 236 +/- 19 and CT+TT 277 +/- 23 mmol/L cells per h; P=0.221). Similarly, no differences were detected in the Vmax of erythrocyte Na+/K+/Cl- cotransport and Na+K+ ATPase among the genotypes. There was no appreciable association between the G-protein beta3-subunit C825T polymorphism and erythrocyte Na+/Li+ CT and other sodium transport systems in the hypertensive patient sample studied; however, those with the T allele were more obese and had more severe systolic hypertension.

Association of the C825T polymorphism of the G-protein β3 subunit gene with hypertension, obesity, hyperlipidemia, insulin resistance, diabetes, diabetic complications, and diabetic therapies among Japanese

“…35 While significant associations of the 825T allelle with obesity have been observed in German, Spanish, Belgian, Chinese, and black African individuals. 3,10,16 No associations have been found in other German and Spanish, as well as Polish, Australian, and Finnish subjects. 8,[13][14][15]17 In Japanese subjects, obesity has not been found, 4,24,27,28 and our result concur.…”

Model-fitting and linkage analysis of sodium–lithium countertransport

“…2 SLC is highly heritable with heritability X65% estimated in Utah pedigrees. 3,4 Nevertheless, no studied polymorphism affects SLC more than modestly (b 3 -adrenergic receptor Trp64Arg, 5 a-adducin (ADD1) Gly460Trp 6,7 ), while others are non-significant (Na-H antiporter, 8,9 angiotensin-converting enzyme insertion/deletion, 10,11 G-protein b 3 -subunit C825T 12 ) or inconsistent (blood group MNS, 10,13 haptoglobin, 10,13 apolipoproteinE (apoE) 14,15 ).…”

SAPHIR - a multi-scale, multi-resolution modeling environment targeting blood pressure regulation and fluid homeostasis

“…analysis of heart rate variability or ventricular contractility) has been shown to provide valuable information for risk-stratification and early detection of cardiovascular pathologies such as cardiac ischemia and heart failure [17,18]. In clinical practice, the analysis of the ANS is commonly performed by applying a set of tests called autonomic manoeuvres (such as the Valsalva manoeuvre [19] or the Tilt test [20]).…”