Declines in inflammation predict greater white matter microstructure in older adults

OBJECTIVE: Protracted, systemic inflammation has been associated with adverse effects on cognition and brain structure, and may accelerate neurodegenerative disease processes; however, it is less clear whether changes in inflammation are associated with brain structure. METHODS: We studied 276 black and white older adults (mean age=83 years at time of imaging) enrolled in a prospective study of aging. Inflammation (measured with CRP) was assessed repeatedly over 6 years (i.e. Year 2, 4, 6, & 8). Brain MRIs were obtained at years 10–11 with DTI; regions of interest included late-myelinating areas vulnerable to aging, including frontal-parietal [superior longitudinal fasciculus (SLF)-dorsal] and temporal (SLF-temporal; uncinate) white matter tracts. RESULTS: Mean CRP values significantly declined (t=−5.54, p<.0001) over 6 years, and subject-specific slopes (BLUPs) all showed a decline (mean=−.57, SD=.53) for our participant sample. More than 50% of study participants were still in the moderate to high cardiovascular risk range based on CRP values at Year 8. After controlling for demographics, vascular risk factors and MRI white matter hyperintensities, larger decreases in CRP values over time were significantly associated with higher fractional anisotropy in the SLF-dorsal [Beta=−0.0052, standard error (SE)=0.003; 95% confidence interval (CI)= −0.0103 to −0.0025, p=.04], SLF-temporal (Beta=−0.0109, SE=0.004; 95%CI=−0.0189 to −0.0029, p=.008), and uncinate (Beta=−0.0067, SE=0.003; 95%CI=−0.0132 to −0.0001, p=.05) fasciculi. CONCLUSIONS: Results suggest that in a prospective cohort of older individuals, faster declines in inflammation over time are related to indicators of white matter health, even after accounting for vascular risk factors

Is ageing associated with a shift in the balance between Type 1 and Type 2 cytokines in humans?

The balance between Type 1 and Type 2 cytokines is important for the outcome of several infectious diseases. As elderly humans show increased morbidity and mortality from infectious diseases, this study tests if ageing is associated with a change towards Type 2 dominance in T cells. Expression of IFN-γ, and IL-4 was measured in CD4+ and CD8+ T cells by flow cytometry in three groups: young controls (n = 28), 81-year-olds (n = 22), and centenarians (n = 25). The major findings were that the percentage of IFN-γ+ as well as IL-4+ T cells was increased in aged subjects. Furthermore, after adjusting for decreased lymphocyte counts in the elderly, the concentration in the blood of IFN-γ+ and IL-4+ CD8+ T cells was still increased in the 81-year-olds. In centenarians, a shift towards a relative dominance of Type 2 cytokine expression was found within CD8+ T cells. Furthermore, the percentage of T cells with cytokine expression was closely correlated to the in vivo expression of CD95 and CD45RO. In conclusion, we found some evidence for an age-related shift towards a Type 2 cytokine profile