Structural, mechanical and functional evaluation in resistance arteries of spontaneously hypertensive rats before and after the hypertension.

• Grant number: 12/11376-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: December 01, 2012
• End date: March 31, 2014
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Luciana Venturini Rossoni
• Grantee: Rafael Magalhães Jeuken
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Hypertension is characterized by the chronic elevation of arterial pressure levels. It is a disease of multiple causes, able to develop changes in vital organs of the organism, such as brain, kidney, heart and blood vessels. Adjustments in blood vessels in hypertension have been under intense research to better understand the mechanisms involved with the genesis of this illness. However, the hypertension establishment and its associated mechanisms are still not completely understood. The comprehension of those is essential, especially due to the high prevalence of this disease amongst other cardiovascular pathologies and because it is an illness without healing, for which only therapeutic strategies that aim its control are available.It is well established that hypertension is characterized by an elevation of the total vascular peripheral resistance, in which small resistance arteries play an essential role. It has been already described that small arteries in spontaneously hypertensive rats (SHR) and human hypertensive patients present the following characteristics: 1. Structural and mechanical eutrophic remodeling, associated with thicker medial layers, but preserved cross-sectional area, with diminished luminal diameter and an increased media/lumen ratio and wall stiffness; 2. Endothelial dysfunction and increased contractile response. However, the mechanisms of establishment of these characteristics are still not fully understood. Few researches aim to compare resistance arteries before and after the hypertension development, and it focused on structural and/or morphometric differences separately, but not the mechanical or even the interrelationships between them or possible key factors for the hypertension development process. Based on that, the present research will evaluate the mechanical, structural and functional characteristics of resistance arteries (of the mesenteric circulation) in SHR, comparing young animals, before their hypertension is established, and adults, with well-established hypertension, matching them with their respective WKY normotensive control. The results obtained in present research may indicate the relation between functional and structural changes during hypertension development in SHR, as well as possible cause and consequence relations that contribute to hypertension pathogenesis.