Insulin-Like Growth Factor I Serum Levels Influence Ischemic Stroke Outcome

Abstract

Background and Purpose— Insulin-like growth factor I (IGF-I) is neuroprotective in animal models of stroke. We investigated whether serum IGF-I levels in patients with acute ischemic stroke influence stroke severity and outcome. Methods— Concentrations of IGF-I and IGF binding protein 3 were measured in serum samples obtained within 6 hours after stroke onset from 255 patients who took part in the placebo arm of the United States and Canadian Lubeluzole in Acute Ischemic Stroke Study. Stroke severity was assessed with the National Institutes of Health Stroke Scale. Multivariate analysis was performed to assess the overall shift in modified Rankin Scale score and changes in the National Institutes of Health Stroke Scale score at 3 months. Survival curves were plotted using the Kaplan-Meier method, and the Cox proportional hazard model was used for multivariate analysis to investigate factors influencing survival. Results— After controlling for statistically relevant risk factors, subjects with high IGF-I levels or IGF-I/IGF binding protein 3 ratios had a better neurological and functional outcome at 3 months. Baseline stroke severity was not different between high and low IGF-I groups. In contrast to the low IGF-I group, neurological symptoms gradually improved from Day 3 in the high IGF-I group. Conclusions— Our results suggest that high serum IGF-I levels just after ischemic stroke onset are associated with neurological recovery and a better functional outcome.

Muscle Atrophy, Voluntary Activation Disturbances, and Low Serum Concentrations of IGF-1 and IGFBP-3 Are Associated With Weakness in People With Chronic Stroke

“…The serum concentration of IGF-1 or the IGF-1/IGFBP-3 complex has been correlated with neurological recovery 19,39 due to IGF-1 anti-apoptotic and neuroprotective actions. 14 De Smedt et al 39 showed that individuals who had elevated levels of serum IGF-I or IGF-I/IGFBP-3 at 6 hours after a stroke were associated with better neurological recovery and functional outcome at 3 months, …”

Modulation of Neural Plasticity as a Basis for Stroke Rehabilitation

“…99 High serum levels of insulin-like growth factor 1 after stroke are associated with neurological recovery and better functional outcome. 100,101 In experimental stroke, insulin-like growth factor 1 treatment improved motor recovery, paralleled by enhanced neovascularization and neurogenesis. 102,103 However, because of its inability to pass through blood-brain barrier, insulin-like growth factor 1 was administered intranasally starting 10 minutes after stroke induction 102 or by adeno-associated virus-mediated gene transfer 3 weeks before stroke.…”

Estrogen-IGF-1 interactions in neuroprotection: Ischemic stroke as a case study

“…In a study of 255 stroke patients, higher IGF-1 levels or a higher IGF-1/IGFBP3 ratio was associated with better functional outcome at 3 months. Interestingly, baseline severity was not different between high and low IGF-1 groups, suggesting that IGF-1 modulates stroke sequelae and not the immediate phase (De Smedt et al, 2011). In a case cohort of older individuals in the Cardiovascular Health Study, neither IGF-1 nor IGFBP-1 predicted MI or stroke, but low IGFBP-3 levels were associated with higher levels of coronary events.…”