Insulin-Like Growth Factor-1 as a Vascular Protective Factor

R ecent advances in cardiology have focused on prolifer- ation and regeneration as potential cardiovascular defense mechanisms.Within this framework, growth factors are acquiring increasing importance; insulin-like growth factor-1 (IGF-1) emerges among them for its versatile pleiotropic actions.This review provides a current perspective on IGF-1 and vascular disease. I. Insulin-Like Growth Factor-1 and VascularDisease: Friend or Foe?The IGF-1 system is dynamic and complex, 1,2 involving at least 6 IGF-1-binding proteins (IGFBP-1 through -6) and several binding protein-related proteases, 1 including pregnancy-associated plasma protein-A (PAPP-A).The latter promotes IGF-1 bioavailability by cleaving IGFBP-4 and -5. 3 Acute coronary syndromes have been associated with raised PAPP-A concentrations in blood, leading to the interpretation that PAPP-A may enhance the risk of coronary artery disease through increased IGF-1 in vascular tissues. 4Recent results, however, suggest a different relation between IGF-1 and ischemic syndromes.