Abstract 15552: Insulin-Like Growth Factor-1 is Lower in Acute Stroke but is Not Related to Recovery

Abstract

Purpose: Insulin-like growth factor 1 (IGF1) sampled within ten days of stroke has resulted in inconsistent findings. When compared to control participants, one study found elevated levels of IGF1 while another reported lower values. Despite these reported differences, there is evidence to suggest that IGF1 may have a neuroprotective effect and may be related to admitting stroke severity and functional independence at one month post-stroke. The possibility exists that a large sampling window and no consideration for insulin-like growth factor binding protein 3 (IGFBP3), may account for the differing results. The purpose of this study was to: 1) determine the difference in IGF1, IGFBP3, and IGF1 ratio in individuals with acute stroke and controls; and 2) determine the relationship of IGF1, IGFBP3, and IGF1 ratio to admission stroke severity and functional independence at one month post stroke. Methods: Blood was collected from 12 individuals with a diagnosis of acute stroke (4 males; 63.9 + 8.4 years) between 7:30 and 9:00 am, after an overnight fast, and within 72 hours of hospital admission. Blood was obtained from 12 age and gender matched healthy controls (4 males; 64.8 + 9.8 years) after an overnight fast during similar hours. Plasma was obtained from blood samples, aliquoted, and frozen within 1 hour of collection. IGF1 and IGFBP3 were quantified using standard procedure ELISAs (Alpco, Salem, NH). Admission NIH Stroke Scale and the modified Rankin Scale (mRS) at one month post stroke was obtained from the electronic medical record. Results: IGF1 (stroke: 113 ng/mL; control: 123 ng/mL, p = .59) and IGFBP3 (stroke: 2350 ng/mL; control: 2593 ng/mL, p = .33) were lower in the acute stroke patients, but not significantly. IGF1 ratio was not different (stroke: .06; control: 05; p = .55) in acute stroke compared to controls. There were no significant relationships between any IGF marker and stroke severity (p > 0.50), nor mRS (p > 0.50). Conclusion: We report that IGF1 and IGFBP3 is lower in acute stroke patients. A single time point of IGF1 and IGFBP3 during acute stroke may not demonstrate a neuroprotective relationship to stroke recovery. Future work should examine percent change in the IGF family to determine whether this may be a more valuable biomarker of stroke recovery.