Extracellular matrix remodeling of subcutaneous small resistance arteries during essential hypertension

Abstract

Remodeling in microvascular structure may impair organ flow reserve and may be impor- tant in the support and also in the progressive worsening of hypertensive disease [1, 2]. In the development of hypertensive microvascular remodeling, a relevant role may be played by changes in extracellular matrix proteins [3]. Aim of this study was evaluate some extracellular matrix components within the tunica media of subcutaneous small arteries of 9 normotensive subjects and 12 essential hypertensive patients. Subcutaneous small resistance arteries were dis- sected and mounted on an isometric myograph and the tunica media to internal lumen ratio was measured. In addition, fibronectin, laminin, transforming growth factor-beta1 (TGF-β1) and emilin-1, important extracellular matrix components, were evaluated together with total colla- gen content and collagen subtypes. Small arteries of normotensive controls presented less total and type III collagen amounts with respect to hypertensive patients. Fibronectin and TGF-β1 contents were significantly greater in essential hypertensive patients, compared with normoten- sive subjects; while laminin and emilin-1 contents were lesser in essential hypertensive patients with respect to normotensive controls. Furthermore, a significant correlation was observed between fibronectin content and media to lumen ratio. In conclusion, our results indicated that in small resistance arteries of patients with essential hypertension may be detected a relevant fibrosis with increased fibronectin and TGF-β1 tunica media contents and decreased laminin and emilin-1 contents. These extracellular matrix changes might be involved in the remodeling of human small resistance artery and so extracellular matrix proteins may be possible targets for new anti-hypertensive drugs.