Mononuclear cell adhesion to collagen ex vivo is related to pulse pressure in elderly subjects

Abstract

Mononuclear cells and platelets are intimately involved in the pathogenesis and complications of cardiovascular disease. Platelet activation has been reported in hypertension, though the activation-state of monocytes has received less attention. In this study the adhesiveness of monocytes and platelets was assessed and any relationship between the adhesive properties of these cellular elements and plasma levels of soluble adhesion molecules and blood pressure parameters determined. Fifty six elderly volunteers, of whom 32 were classified hypertensive (daytime SBP≥135 mmHg), underwent 24 h blood pressure monitoring, assessment of monocyte and platelet adhesion and measurement of the plasma soluble adhesion molecules ICAM-1, L-selectin, E-selectin and vWF. In the elderly hypertensive subjects, monocyte adhesion to collagen coated ( P<0.05) and tissue culture plastic microwells ( P<0.05) was significantly elevated and circulating levels of soluble ICAM-1 ( P<0.01) and soluble E-selectin ( P<0.05) were significantly raised compared to their normotensive counterparts. A significant correlation was found to exist between monocyte adhesion to collagen and daytime pulse pressure ( r=0.39, P<0.01) and also between plasma levels of soluble E-selectin and clinic DBP ( r=0.40, P<0.001). The increased monocyte adhesion witnessed in hypertensive subjects and with increasing pulse pressure may contribute to the increased risk of cardiovascular disease in hypertension. Whether this increased adhesiveness is a property of the monocytes, or reflects endothelial cell activation, remains to be determined.