Effects of angiotensin II-receptor blockers on soluble cell adhesion molecule levels in uncomplicated systemic hypertension: An observational, controlled pilot study in Taiwanese adults

Abstract

Background: Controversy exists as to whether individuals with hypertension without risk factors for atherosclerosis (eg, diabetes mellitus, dyslipidemia, Objective: The aim of this study was to determine whether (1) levels of solubleCAMs (sCAMs) (soluble E-selectin [sE-selectin], soluble intercellular adhesion molecule-1 [sICAM-1 ], soluble vascular cell adhesion molecule-1 [sVCAM-1 ], and von Willebrand factor [vWF]) are elevated in Taiwanese adults with uncomplicated essential hypertension without other risk factors; (2) CAM levels increase with severity (stage) of hypertension; and (3) monotherapy with the angiotensin II-receptor blocker (ARB) irbesartan modulates CAM expression in a subgroup of these patients. Methods: This observational, controlled pilot study was conducted at the Hypertension Clinic, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. Adult patients with uncomplicated essential hypertension without other risk factors (eg, diabetes mellitus, dyslipidemia, obesity) and normotensive controls were eligible. Blood pressure (BP) was determined using 24-hour ambulatory BP monitoring (ABPM) in all participants, and the staging of hypertension was classified based on criteria in The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (normotensive, prehypertension, stage I hypertension, and stage II hypertension). The SCAM levels and 24-hour ABPM were measured before and after 8 weeks of open-label irbesartan monotherapy in a subgroup of the patients with hypertension. Patients who had difficulty achieving the target BP values on irbesartan monotherapy were treated with combination therapy (2 or 3 antihypertensive agents); levels of sCAMs were not measured in these patients. Plasma levels of sE-selectin, the sCAMs, and vWF were measured using enzyme-linked immunosorbent assay. Results: The study comprised 61 patients with uncomplicated essentialhypertension (33 men and 28 women; mean [SD] age, 51 [12] years) and 17 normotensive controls (11 men, 6 women; mean [SD] age, 52 [ 11 ] years). The mean (SD) dose of irbesartan was 243 (63) mg. Hypertensive patients had significantly higher circulating levels of sICAM-1 compared with normotensive controls ( P = 0.009). No significant differences in levels of sVCAM-1, sE-selectin, or vWF were found between hypertensive patients and controls. The mean sICAM-1 level was significantly higher in the prehypertensive patients compared with normotensive controls ( P = 0.03). The mean sE-selectin level was significantly higher in the patients with stage I hypertension compared with the prehypertensive group ( P = 0.01). The 18 patients given 8 weeks of irbesartan monotherapy showed a significant decrease from baseline in systolic and diastolic BP (both, P = 0.001) and sE-selectin (P= 0.006), but not in sVCAM-1 or sICAM. Forty-three patients did not reach target BP on irbesartan monotherapy and thus were treated with combination therapy. Conclusions: Based on the results of this observational, controlled pilotstudy in Taiwanese patients, we suggest that ARB therapy, in addition to reducing BP, has the potential to suppress CAM expression and to improve endothelial dysfunction in hypertension.