Figure 5.

Summary of GH actions for neovascularization and wound healing at different levels. At the BM level the hormone enhances the production and release of EPCs which peripherally mature to ECs. On ECs the hormone activates eNOS leading to NO production; this contributes to improve redox balance. GH decreases peripheral resistances by decreasing SNS. The hormone also acts on the IS leading to an increase in T and B-lymphocytes and the production of antibodies. GH exerts actions on the neurogenic response that results in an increase in SP production. These effects may lead to: (A) angiogenesis, as a result of hypoxia there is a sprout of new capillaries; (B) arteriogenesis, the occlusion of an artery (a) increases shear stress forces that act on preexisting collateral arterioles (b, c) enlarging them and allowing blood flow to bypass the occlusion (b1, c1). Wound healing is one of the consequences of the recovery of blood flow.

BM, bone marrow; EC, endothelial cell; eNOS, endothelial nitric oxide synthase; EPC, endothelial progenitor cell; GH, growth hormone; IS, immune system; NO, nitric oxide; ROS, reactive oxygen species; SNS, sympathetic nervous system; NS, peripheral nervous system;SP, Substance P. SP, Substance P.