Association of methylenetetrahydrofolate reductase gene 677C>T polymorphism with hypertension in older women in a population of Buenos Aires City.

We examined the relationship between the 677C >T polymorphism in the MTHFR gene and tHcy in normotensive (NT) and hypertensive (HT) subjects and the influence of sex and age in a cross-sectional study. Smoking habits, history of vascular disease, diabetes, and tHcy were significantly associated with T allele as hypertension risk factors. The T allele was significantly related with higher tHcy in (i) men versus women (P < .01), (ii) men and women older than 47 years versus the younger ones (P < .05 and P < .001, respectively), (iii) HT women versus NT women (P < .01), and (iv) older HT women versus older NT women (P < .01). We found an association between the 677C>T MTHFR polymorphism and tHcy with hypertension that in women is manifested with age.

Corticoadrenal activity in rat regulates betaine-homocysteine S-methyltransferase expression with opposite effects in liver and kidney.

Betaine-homocysteine S-methyltransferase (BHMT) is an enzyme that converts homocysteine (Hcy) to methionine using betaine as a methyl donor. Betaine also acts as osmolyte in kidney medulla, protecting cells from high extracellular osmolarity. Hepatic BHMT expression is regulated by salt intake. Hormones, particularly corticosteroids, also regulate BHMT expression in rat liver. We investigated to know whether the corticoadrenal activity plays a role in kidney BHMT expression. BHMT activity in rat kidneys is several orders of magnitude lower than in rat livers and only restricted to the renal cortex. This study confirms that corticosteroids stimulate BHMT activity in the liver and, for the first time in an animal model, also up-regulate the BHMT gene expression. Besides, unlike the liver, corticosteroids in rat kidney down-regulate BHMT expression and activity. Given that the classical effect of adrenocortical activity on the kidney is associated with sodium and water re-absorption by the distal tubule leading to volume expansion, by promoting lesser use of betaine as a methyl donor, corticosteroids would preserve betaine for its other role as osmoprotectant against changes in the extracellular osmotic conditions. We conclude that corticosteroids are, at least in part, responsible for the inhibition of BHMT expression and activity in rat kidneys.