Enlarged choroid plexus is associated with reduced gray matter volumes and increased plasma amyloid-beta: a population-based study of older adults.

OBJECTIVES

To characterize brain structures and plasma Alzheimer's-related biomarkers associated with enlarged choroid plexus (ChP) among rural older adults in China.

METHODS

This population-based cross-sectional study included 1115 older adults (age ≥ 60 years) derived from the Multimodal Interventions to delay Dementia and disability in rural China, who underwent structural brain MRI scans (3.0 T) in 2018-2020; of these, plasma biomarkers for Alzheimer's disease and neurodegeneration, i.e., β-amyloid (Aβ) 40, Aβ42, neurofilament light chain (NfL), and total tau, were measured using the Simoa platform for 814 persons. ChP was automatically segmented and quantified on T1-weighted images. Data were analyzed using the voxel-based morphometry (VBM) analysis, general linear regression model, and mediation model.

RESULTS

The enlarged ChP volume was significantly associated with reduced gray matter volume (GMV) mainly in the insular region, hippocampus, parahippocampal gyrus, and left thalamus (P < 0.05). In the plasma biomarker subsample, larger ChP volume was associated with higher plasma Aβ40 and Aβ42, and the association was significant only in men (P for ChP volume × sex interaction < 0.05). The mediation analysis suggested that plasma Aβ40 significantly mediated the association of enlarged ChP volume with the reduced GMV of insular region, hippocampus, and left thalamus in men, with the proportion of mediation being 10.73 %, 6.32 %, and 11.45 %, respectively.

CONCLUSIONS

Enlarged ChP volume was associated with reduced regional GMV and increased plasma Aβ40 in older adults, suggesting that the enlarged ChP might be a neuroimaging marker for the brain aging.