SPP1 and endothelial dysfunction: Although no association of IGF-1 and IGFBP-3 levels with angiopoietin-2 or osteopontin was found, an inverse correlation between IGF-1 levels and asymmetric dimethylarginine (ADMA), an endogenous endothelial nitric oxide synthase inhibitor that impairs nitric oxide production and secretion promoting endothelial dysfunction, was found (r = −0.397; P = 0.04).