Abstract 4139552: High-dimensional single-cell antibody-sequencing (AbSeq) analysis reveals age-associated myeloid cell subsets in coronary artery disease

Introduction: Aging is strongly associated with increased vascular inflammation, particularly in individuals over 65. Given that the development of coronary artery disease (CAD) is positively correlated with age-related inflammation, the precise distribution of myeloid subsets across different ages and CAD severity remains unclear. Objective: To investigate the influence of aging on myeloid heterogeneity using peripheral blood samples from the Coronary Assessment in Virginia (CAVA) cohort. Methods: PBMC samples from CAVA subjects (older ≥65, younger ≤64) were analyzed using AbSeq-based high-dimensional analysis. The Gensini score assessed CAD severity (high_CAD >32, low_CAD ≤ 6). Our analysis included 61 subjects in total, 33 older (18 high_CAD) and 28 younger (14 high_CAD). We examined age-wise associations across myeloid subsets. Results: We identified six major myeloid clusters: classical monocytes (cMo), intermediate monocytes (iMo), non-classical monocytes (nMo), plasmacytoid dendritic cells (pDC), conventional dendritic cells (cDC), and DC3. In all major clusters identified, the proportion of cMos (>75%) was consistently higher across all age groups. Although no significant differences were noted in frequencies of major myeloid populations with age, further analysis revealed significant age-related changes in subclusters. A notable decrease was observed in the cMo_CD33 hi CD9 hi (p=0.043) subsets in older individuals. Ingenuity Pathway Analysis of genes associated with this cluster indicated activation of IL-4, and IL-13 signaling pathways. In older subjects with high_CAD, significant decreases were identified in two specific CXCR3 + subsets, cMo_CD14 lo CD33 lo CXCR3 + (p=0.0001) and cMo_CCR6 + CXCR3 + (p=0.006) compared to those with low_CAD. Gensini correlation analysis in the older population also revealed a significant negative association with two cMo_CXCR3 + subsets. Within myeloid-specific genes in the older population, positive correlations with Gensini scores were observed for Ctsa, Flt3, Ncf1, Cd38, and C1Qb . Conversely, Nr4a1 , Cxcl1, Cxcl2, Cxcl8 , Cd83 , and Dusp2 showed negative correlations. We observed an increase in cMo_TLR4 lo (p=0.02) and a decrease in cMo_CD33 hi CD9 hi (p=0.006) in younger populations with high_CAD compared to low_CAD. Conclusion: Our finding highlights age-related changes in myeloid populations and their association with increased cardiovascular risk, suggesting potential targets for therapeutic intervention.