Association of Plasma Creatine With Inflammation and Cognitive Function in Persons With and Without Alzheimer’s Disease

ABSTRACT

Objective@#Creatine, energy buffer in high energy demanding systems including muscle and brain, may play a beneficial role against neuroinflammation in Alzheimer’s disease (AD), and thus be a potential biomarker. This study aimed to compare the levels of plasma creatine between persons with and without AD and investigate associations of plasma creatine levels with cognitive function and blood-based inflammatory markers. @*Methods@#We classified elderly participants by cognitive statuses normal cognition (NC, n=17), mild cognitive impairment (MCI,n=21), and AD (n=21). To assess cognitive function and inflammatory condition, we performed neuropsychological tests and mea-sured plasma C-reactive protein (CRP) levels, respectively. @*Results@#Plasma creatine levels were comparable among participants with AD, MCI, and NC. In overall participants, plasma cre-atine levels were not associated with neuropsychological test scores, but negatively associated with plasma CRP levels. In AD group, plasma creatine levels were negatively associated with neuropsychological test scores and, although not significant, CRP levels (p=0.086). In participants without AD (NC plus MCI), these associations disappeared. @*Conclusion@#Plasma creatine levels may not be useful as a biomarker indicating cognitive statuses. However, our results suggest that, in AD, plasma levels of creatine might reflect the extent of neuroinflammation as well as cognitive deterioration.