Increased activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger in erythrocytes of patients with essential hypertension
Díez J., Arrázola A., Castiella J., Íñigo B., Cía P.
Department of Medicine, School of Medicine, University of Navarra, Spain
To study the activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger in erythrocytes of patients with essential hypertension.
The study was performed in cells from 48 untreated essential hypertensive patients and 30 normotensive controls with similar age- and sex- distribution.
The activity of the Na(+)-dependent anion exchanger was determined by measuring the 4,4'-diisothiocyanostilbene-2,2'-disulfonate (DIDS) sensitive Li+ influx in fresh cells incubated into a medium containing Li2CO3.
The DIDS-sensitive Li+ influx was higher in hypertensives than controls. With the 100% confidence (upper) limit of the normotensive population as a cut-off point, a subgroup of 11 hypertensives had an abnormally high activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger. Compared with patients with normal exchanger activity, patients with increased exchanger activity were characterized by the following: higher frequency of family history of hypertension; lower serum high-density lipoprotein cholesterol levels and higher plasma aldosterone concentrations. After multiple regression analysis, the DIDS-sensitive Li+ influx was inversely correlated with high-density lipoprotein cholesterol levels.
These results show the presence of a new abnormality of erythrocyte Na+ transport in essential hypertension--increased activity of the Na(+)-dependent Cl(-)-HCO3- anion exchanger. In addition, our findings suggest that from the clinical point of view, patients with this transport abnormality represent a particular subset of essential hypertensives.
CITATION J Hypertens. 1992 Jun;10(6):579-85