Alterations in platelet activity and endothelial glycocalyx biomarkers by treatment with an angiotensin converting enzyme inhibitor or an alpha-1 adrenoceptor antagonist in patients with hypertension: results from the DoRa study.

Drugs blocking the renin-angiotensin-aldosterone system may offer benefit on endothelial function, inflammation, and hemostasis in addition to the effects of reducing blood pressure. We have shown antithrombin effects by treatment with the angiotensin converting enzyme (ACE) inhibitor ramipril. As thrombin is a key inducer of platelet aggregation, we hypothesized that treatment with ramipril could modulate platelet reactivity and endothelial glycocalyx (eGCX) function. This study assessed platelet activity (CD40 ligand and P-selectin) and eGCX markers (E-selectin, hyaluronan, syndecan-1, and thrombomodulin) in 59 individuals with mild-to-moderate hypertension, randomized double-blind to ramipril 10 mg or doxazosin 8 mg od for 12 weeks. Ramipril and doxazosin similarly reduced blood pressure. Antihypertensive treatment reduced CD40 ligand ( < .001) with no interaction ( = .405) by treatment group (reductions by ramipril and doxazosin were 8.7 ± 30.8 ng/L,  = .044, and 13.4 ± 25.5 ng/L,  = .002, respectively). There were no changes in P-selectin by treatment within ( = .556) or between ( = .256) treatment groups. No changes were observed in E-selectin, hyaluronan, syndecan-1, or thrombomodulin by antihypertensive treatment ( = .091-.991), or between ramipril and doxazosin ( = .223-.999). Our results show a potential reduction of platelet activity by ACE inhibitor treatment. Also, the alpha 1-adrenoceptor antagonist doxazosin may reduce platelet activation. Neither drug influenced eGCX markers.