Association of free fatty acid receptor 2 expression in peripheral blood monocytes with carotid atherosclerosis

To investigate the relationship between free fatty acid receptor 2 (FFAR2) expression in peripheral blood monocytes and carotid atherosclerosis (CAS).

Between November 2023 and June 2024, individuals who underwent carotid ultrasound in the inpatient or outpatient settings of Sichuan Provincial People's Hospital were enrolled in this study. Based on the intima-media thickness (IMT) results from the carotid ultrasound examination, participants were categorized into three groups: the non-CAS group (IMT < 1 mm), the carotid intima-media thickness (cIMT) thickening group (1.0 mm ≤ IMT < 1.5 mm), and the carotid plaque (CP) group (IMT ≥ 1.5 mm with invasion of the lumen or limited intimal thickening higher than 50% of peripheral IMT). The expression levels of FFAR2 in peripheral blood monocytes were detected by flow cytometry. Comparative analyses were conducted on general information and monocyte FFAR2 expression levels across these three groups.

A total of 86 cases were enrolled, comprising 21 cases in the non-CAS group, 21 in the cIMT thickening group, and 44 in the CP group. There were significant statistical differences among the three groups in age, history of hypertension, and Hemoglobin A1c levels (P < 0.05). Specifically, the median (interquartile range) expression levels of FFAR2 in peripheral blood monocytes were 32.04 (17.92, 59.48) × 10³, 82.00 (51.19, 99.41) × 10³, and 45.03 (26.86, 82.22) × 10³ for the non-CAS group, the cIMT thickening group, and the CP group, respectively. The results of inter-group comparisons indicated that there were significant differences in the expression levels of FFAR2 in monocytes between the cIMT thickening group and the non-CAS group (P < 0.001). Meanwhile, significant differences in the expression levels of FFAR2 in monocytes were also observed between the cIMT thickening group and the CP group (P < 0.05).

Peripheral blood monocyte FFAR2 expression appears to be potentially associated with CAS. The upregulation of peripheral blood monocyte FFAR2 expression levels may play a role as a negative feedback regulator, potentially influencing the progression of carotid atherosclerosis, although further research is needed to confirm this hypothesis.