Localization of insulin-like growth factor I and inhibition of coronary smooth muscle cell growth by somatostatin analogues in human coronary smooth muscle cells. A potential treatment for restenosis?

In this study, we demonstrate, for the first time, the localization of insulin-like growth factor I (IGF-I) in de novo and restenotic human coronary atherectomy plaques by using immunocytochemical techniques. Smooth muscle cells (SMCs) exhibiting the synthetic phenotype contained a statistically significant higher concentration of IGF-I than SMCs of the contractile phenotype or SMCs from normal coronary arteries. In addition, we provide data to suggest that the long-acting somatostatin analogues octreotide and angiopeptin inhibit IGF-I- and basic fibroblast growth factor (b-FGF)- induced human coronary artery SMC proliferation. Platelet-derived growth factor (PDGF)-stimulated cultures were minimally affected by the addition of octreotide but were significantly inhibited by angiopeptin. All three growth factors stimulated SMC migration in a dose-dependent manner. The somatostatin analogues tested had no effect on growth factor-stimulated SMC migration. Our data suggest that by reducing SMC proliferation, s...