Lanreotide reduces serum free and total insulin-like growth factor-I after angioplasty

Background Several experiments point to a participating role of insulin-like growth factor-I (IGF-I) in the vascular events leading to restenosis after percutaneous transluminal coronary angioplasty (PTCA). Methods and Results We measured fasting serum total (extractable) IGF-I in 553 patients in a controlled clinical trial. Half of the patients received continuous subcutaneous infusion of the somatostatin analogue lanreotide from the day before (baseline) and for 4 days after PTCA. We also measured ultrafiltrated serum free IGF-I and IGF-II, total IGF-II, IGF-binding protein-1 (IGFBP-1), IGFBP-3, and insulin in a subgroup of 18 placebo-treated and 20 lanreotide-treated patients. Total IGF-I had decreased by 7% (P<.0001) 1 day after initiation of lanreotide infusion and stayed reduced, whereas no early changes occurred in placebo-treated patients. The same pattern was observed in the subgroup. Free IGF-I decreased significantly from baseline by 22% to 27% (P<.05) in lanreotide-treated patients and increased insignificantly by 10% to 30% (P=.054) in placebo-treated patients. IGFBP-1 increased (P<.05) in both groups postoperatively, but levels in lanreotide-treated patients exceeded (P<.05) those of placebo-treated patients. Lanreotide treatment resulted in minor reductions (P<.05) in free and total IGF-II and IGFBP-3, whereas insulin was unaltered. Conclusions Lanreotide administration acutely decreases circulating total and free IGF-I, the latter relatively more, and increases IGFBP-1. These alterations in the IGF system may participate in the improvement of the long-term outcome after PTCA noted with lanreotide treatment.