👤 Rima Kaddurah-Daouk

Mounting evidence implicates inflammation as a key factor in Alzheimer’s disease (AD) development. We previously identified pro-inflammatory soluble epoxide hydrolase (sEH) metabolites to be elevated in plasma and CSF of AD participants and to be associated with lower cognition in non-AD subjects. Soluble epoxide hydrolase is a key enzyme converting anti-inflammatory epoxy fatty acids to pro-inflammatory diols, reported to be elevated in multiple cardiometabolic disorders. Here we analyzed over 700 fasting plasma samples from the baseline of Alzheimer’s Disease Neuroimaging Initiative (ADNI) 2/GO study. We applied targeted mass spectrometry method to provide absolute quantifications of over 150 metabolites from oxylipin and endocannabinoids pathway, interrogating the role for inflammation/immune dysregulation and the key enzyme soluble epoxide hydrolase in AD. We provide further insights into the regulation of this pathway in different disease stages, APOE genotypes and between sexes. Additionally, we investigated in mild cognitive impaired (MCI) participants, metabolic signatures that inform about resilience to progression and conversion to AD. Key findings include I) confirmed disruption in this key central pathway of inflammation and pointed to dysregulation of sEH in AD with sex and disease stage differences; II) identified markers of disease progression and cognitive resilience using sex and ApoE genotype stratified analysis highlighting an important role for bile acids, lipid peroxidation and stress response hormone cortisol. In conclusion, we provide molecular insights into a central pathway of inflammation and links to cognitive dysfunction, suggesting novel therapeutic approaches that are based on targeting inflammation tailored for subgroups of individuals based on their sex, APOE genotype and their metabolic profile. The online version contains supplementary material available at 10.1186/s13195-025-01939-9. Show less

Alzheimer's disease (AD) and vascular dementia (VaD) account for most dementia cases. AD biomarkers remain costly and invasive, and no specific biomarkers exist for VaD. We analyzed plasma and brain proteomics in the UK Biobank (N=53,000) and ROSMAP (N=512) to identify shared and distinct proteomic signatures of AD and VaD and assess the influence of the APOE ε4 variant. We identified 55 AD-associated and 49 VaD-associated proteins, with 13 shared. AD proteins were enriched in glycosaminoglycan binding and cholesterol metabolism; VaD proteins in virus receptor activity, cytokine activity and metalloproteinases. Both showed IGF pathway dysregulation. APOE ε4 stratification revealed distinct AD proteomic signatures beyond GFAP and NeFL. Mendelian randomization suggested causal links for SNAP25 in AD, EDA2R and TIMP4 in VaD, and PVR in both. Findings underscore the importance of APOE genotype and highlight SNAP25, EDA2R, TIMP4, and PVR as potential biomarkers and therapeutic targets. Show less