Age-associated chemokine receptor expression profiles in human peripheral blood monocyte subsets predict...

Aging is a major contributor to chronic inflammation and coronary artery disease (CAD), yet how age influences monocyte chemokine receptor expression in relation to disease severity remains incompletely defined.

We performed high-dimensional single-cell antibody sequencing (Ab-Seq) of peripheral blood mononuclear cells from 61 participants (ages 42-78 years) enrolled in the Coronary Assessment of Virginia (CAVA) cohort. Aging was associated with remodeling of monocyte populations, including a reduction in anti-inflammatory classical monocytes and an expansion of immature monocytes. Among younger individuals with severe CAD, intermediate monocyte subcluster iMo_HLA-DR^intCCR2^low was increased, whereas anti-inflammatory classical monocyte cMo_CD33^hiCD163^hiCXCR4⁺ was reduced. In older individuals with progressive CAD, further reductions in CCR6⁺ and CXCR3⁺ classical monocytes were observed. Additional flow cytometry validation confirmed decreased CCR6-expressing classical monocytes in older individuals with high CAD burden. Independent of age, CXCR3-expressing intermediate monocytes were significantly increased in individuals with severe CAD. Transcriptomic analysis of CXCR3⁺ intermediate monocytes demonstrated increased expression of C1Q genes compared with CXCR3^low cells. Interestingly, chemokine receptor expression also correlated with lipid parameters in older individuals where CCR6 expression on intermediate monocytes positively associated with HDL cholesterol and increased with CAD severity, whereas CXCR3 expression on classical monocytes declined with advancing CAD.

Aging is associated with distinct changes in monocyte chemokine receptor expression that relate to CAD severity. These findings identify age- and disease-associated monocyte immune features that may contribute to CAD progression.