FIBRONECTIN AND LAMININ CONTENT IN THE TUNICA MEDIA OF SUBCUTANEOUS SMALL RESISTANCE ARTERIES OF PATIENTS WITH ESSENTIAL HYPERTENSION: PP.11.428

Abstract

Objective: We have previously demonstrated that a pronounced fibrosis, due to an increased content in type 1 collagen, may be observed both in the tunica media and in the adventitia of subcutaneous small resistance arteries of patients with essential hypertension and with primary aldosteronism (JCEM 2006, 91:2638–2642). However, it was suggested that, in the development of hypertensive microvascular remodeling, a relevant role may be played by laminin and fibronectin vascular content, at least in animal models of hypertension. Aim of this study was to evaluate the amount of fibronectin and laminin within the tunica media of subcutaneous small arteries of normotensive subjects and essential hypertensive patients. Design and Methods: We have investigated 6 normotensive control subjects and 10 essential hypertensive patients. All subjects were submitted to a biopsy of subcutaneous fat from the gluteal or the anterior abdominal region. Subcutaneous small resistance arteries were dissected and mounted on an isometric myograph, and the tunica media to internal lumen ratio was measured. In addition, the fibronectin and laminin content within the tunica media was evaluated by immunohistochemistry, with subsequent image analysis (% of area stained). Results: As expected, clinic blood pressure values were higher in essential hypertensive patients (153/89 ± 7/11 mm Hg) than in normotensive controls (116/81 ± 10/5 mm Hg, P < 0.01). The media to lumen ratio was significantly increased in essential hypertensive patients (0.100 ± 0.03) compared with normotensive controls (0.06 ± 0.02, p < 0.01). Fibronectin media content was significantly greater in essential hypertensive patients (7.41 ± 2.28 %), compared with normotensive controls (5.62 ± 0.40, P < 0.05). A significant correlation was observed between fibronectin media content and media to lumen ratio (r = 0.49, p < 0.05). No significant difference in laminin media content was observed between groups (3.7 ± 1.71 % in essential hypertensive patients, 5.63 ± 1.79 % in normotensive controls). Conclusions: Our results indicate that, in small resistance arteries of patients with essential hypertension, fibronectin, but not laminin media content is increased. Fibronectin might be therefore involved in the development of small resistance artery remodeling in humans.