Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 11, 2003
Publication Date: March 1, 2004
Citation: Hausman, G.J., Richardson, R.L. 2004. Adipose tissue angiogenesis. Journal of Animal Science. 2004. v. 82. p. 925-934. Interpretive Summary: Factors that regulate the formation of blood vessels were reviewed. Some of these factors are produced by fat cells and regulated as in other tissues. The relationships between blood vessel formation and fat cell development were also reviewed. Several studies indicate that blood vessel formation may control or regulate fat cell formation. Therefore, developing blood vessels in fat tissue represent a potential target for regulating fat cell development in the growing animal.
Technical Abstract: A review of adipose tissue angiogenesis includes the morphological and cytochemical development of adipose tissue vasculature. Spatial and temporal relationships between fetal vascular and fat cell development are discussed including depot and genetic dependent arteriolar differentiation. In vitro studies indicated that depot dependent vascular traits may be attributable to intrinsic growth characteristics of adipose tissue endothelial cells. Fundamental aspects of angiogenesis including vasculogenesis, angiogenic remodelling and vessel stabilization were reviewed. Critical angiogenic factors include vascular endothelial growth factor (VEGF), VEGF receptors, angiopoietins (Ang), metalloproteinase enzymes and the plasminogen enzymatic system. VEGF is the most critical factor since it initiates the formation of immature vessels and disruption of a single VEGF allele leads to embryonic lethality in mice. Expression of VEGF is influenced by hypoxia, insulin, growth factors and several cytokines. VEGF expression and secretion by adipocytes is regulated by insulin and hypoxia, and is associated with adipose tissue accretion. VEGF accounts for most of the angiogenic activity of adipose tissue. The proposed role of leptin as an adipogenic factor is reviewed with respect to potentiating other angiogenic factors. Potential links between VEGF and leptin gene expression have not been examined but both genes are hypox inducible. Finally, several studies indicate that adipose tissue accretion can be controlled through the vasculature per se.