Neuropathologic Correlates of White Matter Hyperintensities in a Community-Based Cohort of Older Adults

Article type: Research Article

Authors: Arfanakis, Konstantinos^{a; b; c; *} | Evia, Arnold M.^a | Leurgans, Sue E.^{b; d} | Cardoso, Luis F.C.^a | Kulkarni, Arman^a | Alqam, Nabil^a | Lopes, Lucas F.^a | Vieira, Diego^a | Bennett, David A.^{b; d} | Schneider, Julie A.^{b; d; e}

Affiliations: [a] Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, USA | [b] Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL, USA | [c] Department of Diagnostic Radiology and Nuclear Medicine, Rush University Medical Center, Chicago, IL, USA | [d] Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, USA | [e] Department of Pathology, Rush University Medical Center, Chicago, IL, USA

Correspondence: [*] Correspondence to: Konstantinos Arfanakis, PhD, 1750W Harrison, Suite 1000, Chicago, IL 60612, USA. Tel.: +1 312 942 6377; E-mail: konstantinos_arfanakis@rush.edu.

Abstract: Background:The association of white matter hyperintensities (WMH) with age-related vascular and neurodegenerative pathologies remains incompletely understood. Objective:The objective of this work was to elucidate the neuropathologic correlates of WMH in a large community-based cohort of older adults. Methods:Cerebral hemispheres from 603 community-based older adults were imaged with MRI ex vivo. All participants underwent annual clinical evaluation, cognitive assessment, and neuropathologic examination. WMH burden was assessed using a modified Fazekas rating scale. Multiple ordinal logistic regression was used to test the association of WMH burden with an array of age-related neuropathologies, adjusting for demographics. Mixed effects models of cognition controlling for neuropathologies and demographics were used to determine whether WMH burden contributes to cognitive decline beyond measured pathologies. Results:WMH burden in the whole group was associated with both vascular and Alzheimer’s disease (AD) pathologies: arteriolosclerosis (p < 10–4), gross (p < 10–4), and microscopic infarcts (p = 0.04), and amyloid-β plaques (p = 0.028). In non-demented participants (mild or no cognitive impairment) (N = 332), WMH burden was related to gross infarcts (p = 10–4) and arteriolosclerosis (p < 10–4), but not to AD pathology. Similarly, in those with no cognitive impairment (N = 178), WMH burden was related to gross infarcts (p = 8×10–4) and arteriolosclerosis (p = 0.014). WMH burden was associated with faster decline in perceptual speed in both the whole (p = 0.038) and non-demented (p = 0.006) groups. Conclusion:WMH burden has independent associations with vascular pathologies in older adults regardless of clinical status, and with AD pathology later in the progression of AD. Moreover, WMH burden may reflect additional tissue injury not captured with traditional neuropathologic indices.

Keywords: Cognition, magnetic resonance imaging, pathology, white matter hyperintensities

DOI: 10.3233/JAD-190687

Journal: Journal of Alzheimer's Disease, vol. 73, no. 1, pp. 333-345, 2020