64 LOW SALT DIET AFFECTS ANGIOTENSIN RECEPTOR REGULATION ON MONOCYTES AND NEUTROPHILS IN HUMANS

Abstract

Background: Angiotensin II (Ang II) is a key player in hypertension, inflammation and oxidative stress and atherosclerosis. Circulating cells reportedly express AT1 receptors (AT1R). In the present study we assessed AT1R and AT2R in monocytes (MONO) and neutrophils (NEUTRO) during manipulations in salt intake and upon ex vivo cytokine and Ang II stimulation in healthy humans. Methods and results: MONO, NEUTRO more than B-cells, but not T-cells, expressed AT1R AT2R assessed by FACS on fresh whole blood (n = 10). Sodium excretion was 145±37/d, 18±15 mmol/d and 197±81 mmol/d at baseline, low salt and high salt (P<0.01). Low salt did not affect MONO or NEUTRO AT1R or AT2R expression. Stimulation of whole blood with Ang II, a combination of IL6, IFN and TNFα (CytMix) or a combination (Ang+CytMix) for 4 h ex vivo at 37C did not affect AT1R in MONO or NEUTRO at baseline or high salt, but CytMix and CytMix+Ang increased AT1R during low salt. Interestingly, in NEUTRO, the AT2R displayed a decrease upon CytMix and CytMix+Ang, not dependent upon salt intake. Conclusions: MONO and NEUTRO express AT1R and AT2R. Low salt did not affect AT2R or AT1R expression. During low salt intake, MONO and NEUTRO stimulated with CytMix or CytMix+Ang displayed increased AT1R expression. This study shows that salt intake differentially affects AT1R and AT2R expression in leukocyte subtypes.