AUTHOR=Sudheimer Keith D. , O'Hara Ruth , Spiegel David , Powers Bevin , Kraemer Helena C. , Neri Eric , Weiner Michael , Hardan Antonio , Hallmayer Joachim , Dhabhar Firdaus S. TITLE=Cortisol, cytokines, and hippocampal volume interactions in the elderly JOURNAL=Frontiers in Aging Neuroscience VOLUME=6 YEAR=2014 URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2014.00153 DOI=10.3389/fnagi.2014.00153 ISSN=1663-4365 ABSTRACT=

Separate bodies of literature report that elevated pro-inflammatory cytokines and cortisol negatively affect hippocampal structure and cognitive functioning, particularly in older adults. Although interactions between cytokines and cortisol occur through a variety of known mechanisms, few studies consider how their interactions affect brain structure. In this preliminary study, we assess the impact of interactions between circulating levels of IL-1Beta, IL-6, IL-8, IL-10, IL-12, TNF-alpha, and waking cortisol on hippocampal volume. Twenty-eight community-dwelling older adults underwent blood draws for quantification of circulating cytokines and saliva collections to quantify the cortisol awakening response. Hippocampal volume measurements were made using structural magnetic resonance imaging. Elevated levels of waking cortisol in conjunction with higher concentrations of IL-6 and TNF-alpha were associated with smaller hippocampal volumes. In addition, independent of cortisol, higher levels of IL-1beta and TNF-alpha were also associated with smaller hippocampal volumes. These data provide preliminary evidence that higher cortisol, in conjunction with higher IL-6 and TNF-alpha, are associated with smaller hippocampal volume in older adults. We suggest that the dynamic balance between the hypothalamic-pituitary adrenal axis and inflammation processes may explain hippocampal volume reductions in older adults better than either set of measures do in isolation.