Late life depression tied to markers of Alzheimer’s pathology

Late life depression (LLD) seems to be correlated with Alzheimer’s disease (AD), particularly as regards markers of pathology such as amyloid dysmetabolism and declining cognition, a recent study has found.

Researchers conducted a cross-sectional analysis of 145 participants, of whom 66 had predementia AD and 38 had LLD; the remaining 41 were designated as normal controls (NC). Relevant cerebrospinal fluid (CSF) markers such as beta-site amyloid-precursor-protein cleaving enzyme 1 (BACE1), neurogranin (Ng), and amyloid-β 42/40 ratio, were compared across groups.

CSF levels of Ng were significantly elevated in patients with LLD and AD than NC (508.9±356.1 vs 303.8±107.1; p<0.01). The same remained true when comparing controls with participants with predementia AD (559.8±195.5; p<0.0001), but not with LLD but no AD (264.4±83.9).

BACE1 levels were likewise significantly elevated in patients with predementia AD relative to controls (2,847.4±770.2 vs 2,205.7±585.9; p<0.01). A similar elevation was reported for LLD AD participants (2,849.9±1,000.3), though it failed to reach statistical significance. The difference between no-AD LLD and control groups was not significant.

Notably, LLD showed no significant impact on CSF levels of amyloid-β 42/40 ratio.

“Our study may contribute to a better understanding of LLD underlying mechanisms and to a better conceptualization of LLD considering clinical overlap with predementia AD. The clinical implications of our findings lie in the CSF based identification of LLD patients with a higher risk of developing AD dementia,” the researchers said.