Durk Pearson & Sandy Shaw’s®
Life Extension NewsTM
Volume 15 No.
5 • September 2012
Increased Inflammatory Activity Associated with Cognitive Decline
Another new paper reports that, in a human study, increased (detectable) levels of a peripheral marker of inflammation, C-reactive protein (CRP), was associated with decreased performance in episodic memory and delayed recall and recognition memory as compared to those with lower (undetectable) levels in a sample of people recruited to participate in a study of healthy aging and cognition. Moreover, those with detectable levels of CRP were found by MRI to have smaller volumes of their brains’ left medial temporal lobe, an area the authors explain is known to mediate verbal memory consolidation.
The subjects were 141 apparently neurologically healthy older adults aged between 65 and 90 years, with 76 of those having detectable levels of CRP and 65 having undetectable levels of CRP. Some earlier studies had found that non-demented older adults with higher levels of systemic inflammatory markers performed less well on verbal memory tests at baseline and were at risk for future decline. However, the authors note that, “the relationship between inflammation and memory is not consistent, as additional cross-sectional and longitudinal studies have failed to find an appreciable connection between inflammation and memory function.” They explain that “the relative lack of neuroimaging data renders it difficult to interpret prior evaluations of the relationship (or lack thereof) between verbal memory and laboratory indices of inflammation, as discrepancies in results may be due to changes in cognitive function that are not dependent on the medial temporal lobes.” The neuroimaging showed that the volume of the left medial temporal lobes in participants with detectable CRP was 7.71 cc, SD = 0.7, while the volume of the same brain area in those with undetectable CRP was 8.02 cc., SD - 0.8, the difference was significant. However, no group differences were detected in other brain areas imaged, including left temporal neocortex, left middle frontal, left lateral frontal, or left parietal neocortex.
The authors caution that in the interpretation of the results, it should be kept in mind that the study is cross-sectional (thus allowing for associations but not for causal inferences) and used only one inflammatory marker (CRP) to stand in for inflammatory activity.
In sum, these results, suggest the authors, “underscore a potential role for inflammation in cognitive aging.”
- Bettcher et al. C-reactive protein is related to memory and medial temporal brain volume in older adults. Brain Behav Immun 26:103-8 (2012).