Angiogenesis in atherosclerosis: An overview

Abstract

Angiogenesis, the process of formation of new blood vessels, involves a complex interplay of various growth signals and cellular milieu. It plays an important role in many physiological and pathological processes. The study of angiogenesis has gained momentum from two different perspectives. On the one hand, angiogenesis is essential for physiologic processes such as menstrual bleeding, wound healing, and embryonic development; on the other hand, histopathologic studies suggest that angiogenesis has an important role in the growth of the atherosclerotic plaque and several tumors. From a clinical perspective, drugs that inhibit angiogenesis seem to increase the incidence of thromboembolic events. Recent data suggests that endothelial-derived growth factor (VEGF) constitutes only a small proportion of total body VEGF and does not contribute significantly to the overall angiogenic response. However, such autocrine VEGF signaling is required for endothelial cell survival and maintenance of vascular homeostasis. In parallel, the discovery of VEGF has guided us to therapeutic angiogenesis as a possible treatment for ischemic heart and peripheral disease. Results of numerous preclinical studies have provided evidence that angiogenic growth factors can promote collateral channel development which can reduce ischemia. Nonetheless, clinical trials on therapeutic angiogenesis have not been very impressive as expected. Bench and bedside research continues to bring insight into the mechanisms of tissue ischemia and tumor growth. Further understanding of different facets of angiogenesis may help in the development of novel and specific therapies.