Which of the following statements regarding angiogenesis are true?

b. C-X-C chemokines regulate angiogenesis

d. Sites of atherosclerosis demonstrate chronic angiogenic activity 

An important component of tissue repair and wound healing is the process of angiogenesis. This normal, physiologic process is a local, transient event which is regulated strictly. A biological imbalance in the production of angiogenic and angiostatic factors contributes to the pathogenesis of several angiogenesis-dependent disorders. These include both malignant and nonmalignant disorders such as rheumatoid arthritis, scleroderma, psoriasis, atherosclerosis, and idiopathic pulmonary fibrosis. Persistent neovascularization in these benign disorders is a prerequisite for the perpetuation of fibroproliferation. IL-8 and potentially other C-X-C chemokines are involved with the angiogenesis process. IL-8 is a potent angiogenic factor. In contrast, another member of the C-X-C chemokine family, PF-4 has angiostatic properties. This suggests that the C-X-C chemokines may function as either angiostatic or angiogenic factors, and the biologic balance that is maintained between these factors may govern overall angiogenic potential in a variety of physiological and pathophysiological states.