Abstract
Gait speed is a useful predictor of adverse outcomes, including incident mobility disability and mortality in older adults. While aerobic exercise training (AEX) is generally an effective therapy to improve gait speed, individual responses are highly variable. Circulating microRNAs (miRNAs) may contribute to inter-individual changes in gait speed with AEX. We examined whether plasma miRNAs are associated with gait speed changes (dGaitSp) in 33 obese older adults (age: 69.3±3.6 years, BMI: 34.0±3.1 kg/m2, 85% white, 73% women) who performed treadmill walking, 4 days/week for 5 months. Gait speed (baseline: 1.02±0.19 m/s; range of response: −0.2 to 0.35 m/s) was assessed using a 400 meter-fast-paced walk test. Using Nanostring technology, 120 out of 800 miRNAs were found to be abundantly expressed in plasma and 4 of these were significantly changed after AEX: miR-376a-5p increased, while miR-16-5p, miR-27a-3p, and miR-28-3p all decreased. In addition, baseline miR-181a-5p levels (r=-0.40, p=0.02) and percent changes in miR-92a-3p (r=-0.44, p=0.009) associated negatively with dGaitSp. Linear regression combined baseline miR-181a-5p and miR-92a-3p levels showed even stronger associations with dGaitSp (r=-0.48, p=0.005). These results suggest that circulating miR-181a-5p and miR-92a-3p may predict and/or regulate AEX-induced gait speed changes in obese older adults.
Highlights
Age-related declines in physical function and subsequent disability are major contributors to morbidity and mortality in older adults [1, 2]
Association between gait speed changes and circulating miRNA levels None of the 4 miRNAs that were altered with aerobic exercise training (AEX) were associated with gait speed changes in response to AEX; we analyzed whether other abundant circulating miRNAs were associated with gait speed changes
We found that changes in gait speed were negatively associated with baseline levels of miR-181a-5p, but not with percent changes in miR181a-5p with AEX (Figure 2)
Summary
Age-related declines in physical function and subsequent disability are major contributors to morbidity and mortality in older adults [1, 2]. Among those physical function measurements, gait speed has been reported to be a useful predictor of adverse outcomes, including incident mobility disability and mortality in older adults [3,4,5,6]. Aerobic exercise training (AEX) is generally effective for improving physical function in older adults, there exists interindividual variation in response to standardized AEX interventions [8, 9]. Identification of novel biomarkers that predict www.aging‐us.com gait speed responses to exercise training will be crucial for clinicians to select intervention regimens in a personalized manner
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