Abstract TMP35: Higher Predicted Aerobic Fitness is Related to Above Median Insulin-like Growth Factor 1 in Individuals With Acute Stroke

Abstract

Background: In healthy individuals, higher circulating insulin-like growth factor-1 (IGF-1) is related to higher aerobic fitness, measured as peak VO 2 . IGF-1 has been shown to possess neuroprotective qualities after stroke. Prior work suggests that elevated IGF-1 within the first week of stroke lead to increased survival rates and less severe stroke impairments at one month. However, it is unclear whether higher aerobic fitness is related IGF-1 levels after stroke. It is difficult to measure peak VO2 during the acute hospital stay. However, using a previously established peak VO2 prediction equation would allow us to address this gap in knowledge. By understanding the interaction of IGF-1 and estimated peak VO 2 after stroke, knowledge can be gained in people post-stroke. We hypothesize that individuals with acute stroke and above median levels of IGF-1 will have significantly higher estimated peak VO 2 at the time of admission. Methods: Twenty-two individuals (10 male; 61 ± 11 years of age) with a diagnosis of acute stroke were enrolled into our study. Blood was sampled within 72 hours of hospital admission under fasting conditions between the hours of 7:30 and 9 am. Samples were centrifuged to obtain plasma, aliquotted, and frozen until assaying. Standard ELISA analyses were used to quantify total IGF-1. Upon enrollment, peak VO 2 was estimated using a previously established equation that considered a self-report measure of physical activity level, age, gender, BMI, and resting heart rate. Results: Median level of IGF-1 was 121 ng/mL. Those who had above median levels of IGF-1 had significantly higher estimated peak VO 2 (29.8 ± 7.9 ml/kg/min) compared to those with lower than median IGF-1 levels (20.9 ± 7.6 ml/kg/min; p = .014). Conclusion: Our data suggests that being physically active prior to stroke and possessing a higher estimated peak VO 2 may have higher IGF-1 levels in individuals after stroke. This may provide some neuroprotective benefit. Future trials with a larger sample size are needed to determine if higher IGF-1 is related to measured aerobic fitness after stroke.