Vasoactive alterations in lower limb subcutaneous resistive arteries from Caribbean patients with atherosclerosis

ABSTRACT

OBJECTIVE: This study was performed to investigate the endothelium-dependent relaxation and contractile responses to endothelin-1 in subcutaneous resistive arteries from Caribbean patients with advanced atherosclerotic femoro-crural arterial disease. DESIGN AND METHODS: Small subcutaneous arteries (inner diameter 200 um) from control subjects (n=8) and atherosclerotic patients (n=8) were dissected from fat biopsies obtained at routine vascular surgery and mounted in vitro on a wire-myograph measuring parietal tension under isometric conditions. RESULTS: Acetylcholine-induced relaxation (10-6 M) was significantly reduced in pre-contracted arteries from atherosclerotic patients (24 + or - 16 percent vs 17 percent in control, p<0.001). Smooth muscle relaxation to sodium nitroprusside was comparable in both groups. Contractions elicited by endothelin-1 (10-9 M) were significantly lower and almost suppressed in both the atherosclerotic group (1.2 + or - 0.8 Kpa) and in the hypertensive subgroup of control subjects (n=4, 1.2= 0r - 1.2 Kpa) comparatively to normotensive control subjects (12.3 + or - 6.9 Kpa, p<0.001). Contractile responses induced by endothelin-1 at higher concentrations (10-8 - 10-7 M), noradrenaline and hyperosmolar potassium were comparable in both groups. CONCLUSIONS: These data suggest a specific impairment of both endothelium-dependent relaxation and contractility in lower limb subcutaneous resistive arteries from Caribbean patients with atherosclerotic femoro-crural arterial disease. These changes in vessels which largely determine proximal vascular resistance may contribute to ischaemic complications in this vascular bed including skin ulcerations and gangrene.(Au)