Click to go to Berkowitz Lab HomePage
Angiogenesis: a Brief Introduction
Angiogenesis is the process of generating new capillary blood vessels from existing blood vessels.
The angiogenesis process begins with the degradation of the basement membrane by proteases secreted by activated endothelial cells that will migrate and proliferate, leading to the formation of solid endothelial cell sprouts into the stromal space. Then, vascular loops are formed and capillary tubes develop with formation of tight junctions and deposition of new basement membrane.
The switch to the angiogenic phenotype involves a change in the local equilibrium between positive and negative regulators of the growth of microvessels.
Positive and negative regulators of angiogenesis Positive regulators Negative regulators Fibroblast growth factors Thrombospondin-1 Placental growth factor Angiostatin Vascular endothelial growth factor Interferon alpha Transforming growth factors Prolactin 16-kd fragment Angiogenin Metallo-proteinase inhibitors Interleukin-8 Platelet factor 4 Hepatocyte growth factor Genistein Granulocyte colony-stimulating factor Placental proliferin-related protein Platelet-derived endothelial cell growth factor Transforming growth factor beta?
Abnormal angiogenesis occurs when the body loses its control of angiogenesis, resulting in either excessive or insufficient blood vessel growth. For instance, conditions such as ulcers, strokes, and heart attacks may result from the absence of angiogenesis normally required for natural healing. On the contrary, excessive blood vessel proliferation may favour tumor growth and spreading, blindness, and arthritis.
Click to go back to Berkowitz Lab HomePage
[[Edited from http://www.med.unibs.it/~airc/angiogen.html]