Atherosclerotic lesions develop and progress more rapidly in diabetic patients than in nondiabetic individuals. This may be caused by accelerated lesion formation in the high-glucose environment of diabetes. Smooth muscle cells (SMCs) cultured in high glucose are more responsive to growth factors such as insulin-like growth factor–1 (IGF-1). This enhanced response to IGF-1 is due in part to increased activation of the αVβ3 integrin. We tested whether αVβ3 integrin activation was increased in diabetic animals and whether an antibody to β3 would inhibit IGF-1 action and development of atherosclerosis. Eight male pigs were made diabetic with streptozotocin and fed a high-fat diet. A F(ab)2 antibody fragment directed at β3 was infused into one femoral artery, whereas the other artery received control F(ab)2 for 3.5 months. There was a 65 ± 8% reduction in atherosclerotic lesion area in the arteries treated with F(ab)2 antibody to β3. Phosphorylation of β3 was reduced by 75 ± 18% in vessels treated with the antibody. Shc and mitogen-activated protein kinase phosphorylation, which are required for IGF-1–stimulated SMC proliferation, were also significantly reduced. We conclude that activation of IGF-1 receptor and αVβ3-linked signaling pathways accelerates atherosclerosis in diabetes and that administration of an antibody to β3 to diabetic pigs inhibits αVβ3 activation, IGF-1–stimulated signaling, and atherosclerotic lesion development. This approach offers a potential therapeutic approach to the treatment of this disorder
