Low circulating adropin levels in late-middle aged African Americans with poor cognitive performance

Abstract

Recent data implicate the secreted peptide adropin in the physiology of aging. In humans, adropin is highly expressed in brain tissues, and correlates positively with transcriptomic signatures of mitochondrial and synaptic functions. Adropin treatment improves performance of old mice in cognitive tests requiring learning and memory. While detected in the circulation of humans, no studies have investigated relationships between adropin, cognitive decline and aging. Here we compared serum adropin concentrations with Mini-Mental State Exam (MMSE) and animal naming test results from a cohort study of African Americans in late-middle age (baseline ages 49-65y, n=357). Using the lowest quintile of the MMSE to identify participants at risk for mild cognitive impairment (MCI) indicated lower serum concentrations (2.95±1.32 ng/ml vs. 3.31±1.56, P<0.05). Grouping into bins using 1-ng/ml increments in serum adropin concentrations further indicated an association between very low serum adropin concentrations and MCI. Using fructosamine as an indicator of moderate-term glucose levels suggested low serum adropin concentration correlate with increased risk of 10-year all-cause mortality in situations of poor glucose control. In summary, these data suggest low circulating adropin concentrations identify late-middle aged people at risk for cognitive impairment, and for all-cause mortality in situations of poor glucose control.