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Figure 2. Proposed mechanisms of G-CSF action
Upon occlusion of an artery, blood flow is redirected to preexisting arteriolar connections, thereby increasing shear stress and inducing collateral artery growth. During uninfluenced arteriogenesis, this process is not effective enough to save myocardial tissue from extensive damage. Application of G-CSF, however, promotes arteriogenesis by mobilizing leukocytes from bone marrow and by up-regulation of ICAM-1 in arteriolar connections. Upon binding to ICAM-1 and extravasation leukocytes supply growth factors and cytokines to collateral arteries entailing an augmented proliferation of arteriolar cells and therefore collateral artery growth. This effect is associated with an improved blood supply in ischemic region showing beneficial effects on development of infarct size and consequently myocardial function.
