U-prostasin concentration may help diagnose primary aldosteronism
An elevated concentration of urinary prostasin (u-prostasin) in humans serves as a specific marker for primary aldosteronism, which involves the classical model of epithelial Na channel activation, according to a recent study.
However, there is no statistically significant difference in prostasin concentrations among patients with different primary aldosteronism subtypes.
Researchers recruited 62 primary aldosteronism and 56 essential hypertension patients to investigate if u-prostasin concentrations were higher in patients with primary aldosteronism than in patients with essential hypertension, and whether u-prostasin measurements could be a useful marker for detecting primary aldosteronism in hypertensive patients.
ELISA was used to measure u-prostasin levels, and routine laboratory methods were applied to assess biochemical and hormonal parameters.
Levels of u-prostasin were higher in primary aldosteronism patients than in essential hypertension patients. Prostasin levels were positively associated with the aldosterone-to-renin ratio and inversely associated with plasma K and urinary Na levels.
In the highest concentration quartile, an association was observed between u-prostasin levels and a several-fold higher probability of primary aldosteronism diagnosis in hypertensive patients. Based on a receiver operating characteristic curve analysis, prostasin was a specific but poorly sensitive diagnostic marker for primary aldosteronism.
The clinical usefulness of the prostasin assay could be further explained with more studies involving a larger series of patients, according to researchers.
“Prostasin is a glycosylphosphatidylinositol-anchored serine protease that is released in urine and is involved in epithelial Na channel activation,” researchers said. “A direct association between u-prostasin concentration and activation of the aldosterone-driven pathway has been suggested [in previous studies].”