Angiogenesis

• influences of the basement membrane cause endothelial cells to grow a blind path

• eventually, these endothelial cells grow into another capillary, this one actually patent

• because this process partly based on chance, a defect several inches wide and two feet long poses much more significant problems for angiogenesis, for example, than a much smaller lesion

• the growth of these new vessels proceeds via specific stages

  • proteolysis of the extracellular matrix

  • migration of fibrin and fibronectin and chemotaxis

  • proliferation

  • lumen formation

  • increased permeability through gaps

    • new vessels growing into a tumor often have increased permeability and can be detected on X-rays

    • chemotherapy takes advantage of this increased permeability; increased permeability helps chemotherapy to be selective for cancerous grwoths

    • angiogenesis can be inhibited by Avastin, and this is another way of retarding the growth of tumors

Category: Pathology Notes