A physiological concept unmasking vascular salt sensitivity in man

About one third of the population worldwide is supposed to be salt sensitive which is a major cause for arterial hypertension later in life. For preventive actions it is thus desirable to identify salt-sensitive individuals before the appearance of clinical symptoms. Recent observations suggest that the vascular endothelium consists of two salt-sensitive barriers in series, the glycocalyx that buffers sodium and the endothelial cell membrane that contains sodium channels. Glycocalyx sodium buffer capacity and sodium channel activity are conversely related to each other. For proof of concept, a so-called salt provocation test (SPT) was developed that should unmask vascular salt sensitivity in humans at virtually any age. Nineteen healthy subjects, ranging from 25 to 63 years of age, underwent two series of 1-h blood pressure measurements after acute ingestion of a salt cocktail with or without addition of a sodium channel blocker effective in vascular endothelium. Differential analysis of the changes in diastolic blood pressure (net ∆DP) identified 12 individuals (63 %) as being salt resistant (net ∆DP = −0.05 ± 0.62 mmHg) and seven individuals (37 %) as being salt sensitive (net ∆DP = +6.98 ± 0.75 mmHg). Vascular salt sensitivity was not related to the age of the study participants. It is concluded that the SPT could be useful for identifying vascular salt sensitivity in humans already early in life.