title: Advances and challenges in skeletal muscle angiogenesis.
abstract: The role of capillaries is to serve as the interface for delivery of oxygen and removal of metabolites to/from tissues. During the past decade there has been a proliferation of studies that have advanced our understanding of angiogenesis, demonstrating that tissue capillary supply is under strict control during health but poorly controlled in disease, resulting in either excessive capillary growth (pathological angiogenesis) or losses in capillarity (rarefaction). Given that skeletal muscle comprises nearly 40% of body mass in humans, skeletal muscle capillary density has a significant impact on metabolism, endocrine function, and locomotion and is tightly regulated at many different levels. Skeletal muscle is also high adaptable and thus one of the few organ systems that can be experimentally manipulated (e.g., by exercise) to study physiological regulation of angiogenesis. This review will focus on the methodological concerns that have arisen in determining skeletal muscle capillarity and highlight the concepts that are reshaping our understanding of the angio-adaptation process. We also summarize selected new findings (physical influences, molecular changes, and ultrastructural rearrangement of capillaries) that identify areas of future research with the greatest potential to expand our understanding of how angiogenesis is normally regulated, and that may also help to better understand conditions of uncontrolled (pathological) angiogenesis.
authors.affiliation: Center for Cardiovascular and Respiratory Sciences and Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, West Virginia; imolfert@hsc.wvu.edu.
authors.forename: I Mark
authors.initials: IM
authors.lastname: Olfert
authors.affiliation: Institute of Anatomy, University of Bern, Bern, Switzerland;
authors.forename: Oliver
authors.initials: O
authors.lastname: Baum
authors.affiliation: Integrative Physiology Group, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark; and.
authors.forename: Ylva
authors.initials: Y
authors.lastname: Hellsten
authors.affiliation: School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom.
authors.forename: Stuart
authors.initials: S
authors.lastname: Egginton
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D002196:Capillaries / Q000502:physiology / Q000648:ultrastructure; D015444:Exercise / Q000502:physiology; D006801:Humans; D018482:Muscle, Skeletal / Q000098:blood supply*; D009389:Neovascularization, Pathologic / Q000503:physiopathology*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology; D040262:Receptors, Vascular Endothelial Growth Factor / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000502:physiology
chemical_list: D042461:Vascular Endothelial Growth Factor A; D040262:Receptors, Vascular Endothelial Growth Factor
keywords: exercise; human; rodent; training