Decreased Toll-like receptor 4 and CD11b/CD18 expression on peripheral monocytes of hypertensive patients correlates with a lesser extent of endothelial damage—a preliminary study.

Abstract

Abstract Background Low-grade chronic inflammation is recognized to contribute to the physiopathology of arterial hypertension. Therefore, this study aimed to assess the pro-inflammatory phenotype of peripheral monocytes of hypertensive patients by analyzing Toll-like receptor 4 (TLR4) and CD11b/CD18 surface expression. In the second part, the influence of phenotypic alterations of monocytes on the endothelial status reflected by circulating endothelial cells (CECs) was evaluated. Patients The study involved thirty patients with mild hypertension (MH) and thirty subjects with resistant hypertension (RH). The control group included thirty-three age and sex-matched normotensive volunteers. Results Reduced TLR4 and CD11b/CD18 surface expression was found in MH and RH patients compared to normotensive volunteers. In addition, the percentage of monocytes co-expressing TLR4 and CD11b/CD18 decreased with the clinical severity of the disease. A statistically significant correlation between TLR4 and CD18 expression was observed in MH patients. Decreased TLR4 surface expression was inversely associated with plasma TNF-α levels in RH patients. A decreased TLR4 surface expression in MH patients and losing CD11b/CD18 on cell membrane in RH patients correlated with a lower number of CECs. Conclusion Our preliminary study showed for the first time that hypertension of varying severity is accompanied by phenotypic changes in monocytes, manifested by reduced surface expression of both TLR4 and CD11b/CD18. This phenotypic feature may allow monocytes to downregulate inflammatory response and limit vascular damage. Our study opens a new unexplored area of research on the anti-inflammatory function of monocytes in hypertension.