Interleukin-8 and interleukin-10, brain volume and microstructure, and the influence of calorie restriction in old rhesus macaques

• Published in: AGE Vol. 35; no. 6; pp. 2215 - 2227
• Main Authors: Willette, A. A., Coe, C. L., Birdsill, A. C., Bendlin, B. B., Colman, R. J., Alexander, A. L., Allison, D. B., Weindruch, R. H., Johnson, S. C.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2013; Springer Nature B.V
• Subjects: Age; Aging; Alzheimer's disease; Animal cognition; Animals; Biomedical and Life Sciences; Brain - cytology; Brain - growth & development; Brain - metabolism; Brain research; Caloric Restriction; Calories; Cell Biology; Cognitive ability; Cytokines; Diet; Enzyme-Linked Immunosorbent Assay; Gene expression; Geriatrics; Geriatrics/Gerontology; Interleukin-10 - metabolism; Interleukin-8 - metabolism; Laboratories; Life Sciences; Macaca mulatta; Macaca mulatta - growth & development; Magnetic Resonance Imaging; Molecular Medicine; Monkeys & apes; Neurotoxicity; Neutrophils; Organ Size; Regression analysis; Prefrontal cortex; Interleukin-10; Interleukin-8; Voxel; Hippocampus; Calorie restriction
• ISSN: 0161-9152; 2509-2715; 1574-4647; 2509-2723
• DOI: 10.1007/s11357-013-9518-y

Higher systemic levels of the proinflammatory cytokine interleukin-6 (IL-6) were found to be associated with lower gray matter volume and tissue density in old rhesus macaques. This association between IL-6, and these brain indices were attenuated by long-term 30 % calorie restriction (CR). To extend these findings, the current analysis determined if a CR diet in 27 aged rhesus monkeys compared to 17 normally fed controls reduced circulating levels of another proinflammatory cytokine, interleukin-8 (IL-8), and raised levels of anti-inflammatory interleukin-10 (IL-10). Further, these cytokines were regressed onto imaged brain volume and microstructure using voxel-wise regression analyses. CR significantly lowered IL-8 and raised IL-10 levels. Across the two dietary conditions, higher IL-8 predicted smaller gray matter volumes in bilateral hippocampus. Higher IL-10 was associated with more white matter volume in visual areas and tracts. Consuming a CR diet reduced the association between systemic IL-8 and hippocampal volumes. Conversely, CR strengthened associations between IL-10 and microstructural tissue density in the prefrontal cortex and other areas, particularly in a region of dorsal prefrontal cortex, which concurred with our prior findings for IL-6. Consumption of a CR diet lowered proinflammatory and increased anti-inflammatory cytokine concentrations, which lessened the statistical association between systemic inflammation and the age-related alterations in important brain regions, including the hippocampus.