Small artery remodeling: current concepts and questions.

Blood flow regulation by small arteries and arterioles includes adaptation of both vascular tone and structure. It is becoming clear that tone and remodeling of resistance vessels are highly interrelated. Indeed, concepts pointing to continuous resistance artery adaptation and plasticity are emerging. The purpose of this review is to summarize such concepts and approaches related to vascular organization and remodeling, and to point out the missing links and possible directions for future research. We focus on the individual vessel level. Since several relevant studies are based on isolated vessels, we briefly re-iterate the available isobaric and isometric approaches. We further discuss the major elements of the small artery wall and their relation to the passive and active mechanical properties, as important determinants for vascular remodeling. The cytoskeletal elements and actin re-organization during remodeling are discussed, as well as the re-lengthening of smooth muscle cells during prolonged constriction. We then consider tone as major causal factors in remodeling and discuss the role of vessel wall inflammation. Finally, we illustrate examples of current quantitative, integrative approaches of small artery mechanosensing and adaptation that may lead to a physiomics description of small artery adaptation in health and in diseases such as hypertension. Copyright 2009 S. Karger AG, Basel.