Intravenous tissue plasminogen activator in patients with stroke increases the bioavailability of insulin-like growth factor-1

Background and Purpose-Insulin-like growth factor (IGF)-1 has potent neuroprotective properties. We investigated the effects of intravenous administration of tissue plasminogen activator (tPA) on serum levels of IGF-1 and IGF-binding protein (IGFBP)-3 in patients with acute ischemic stroke. Methods-Serum levels of total IGF-1, free IGF-1, and IGFBP-3 were measured by radioimmunoassay in 10 patients with ischemic stroke treated with intravenous tPA (0.9 mg/kg body weight) and 10 untreated controls. Results-During tPA treatment, total IGF-1 and IGFBP-3 serum levels did not change, but there was an approximate to 70% increase in free IGF-1 serum levels from 0.98 +/- 0.25 at baseline to 1.69 +/- 0.18 nmol/L at the end of the I-hour infusion (P=0.01). Conclusions-Intravenous therapy with tPA enhances the bioavailability of IGF-1. Conclusions-Intravenous therapy with tPA enhances the bioavailability of IGF-1.