Patients with coronary atherosclerosis had an altered ratio of monocyte subpopulations in the blood, which was associated with an inflammatory cell response

Coronary artery disease (CAD) is one of the leading causes of death in developed countries. Experimental data confirm the role of monocytes in the development of CAD. Three main subpopulations of circulating blood monocytes are known: classical CD14⁺⁺CD16^- (~80%), intermediate CD14⁺CD16⁺ (~5%) and non-classical CD14⁺CD16⁺⁺(~15%). It is believed that each of the subpopulations of monocytes performs different functions. There are studies that demonstrate that classical monocytes respond more to the bacterial presence, whereas non-classical ones respond to the viral one. However, the functions of monocyte subpopulations have not been fully studied. Previously, we demonstrated that circulating monocytes of the blood of patients with atherosclerosis had increased proinflammatory activity. We decided to find out how the ratio of monocyte subpopulations in the blood is related to the inflammatory response of cells in atherosclerosis. The aim of our work was to investigate the relationship of the inflammatory response of primary monocytes with the distribution of monocyte subpopulations relative to the total pool of monocytes in healthy and sick CAD. The study included 20 men aged 46 to 70 years, 10 of them without CAD and 10 patients with CAD. A coronary angiography was performed, according to the results of which the patients were divided into patients with coronary atherosclerosis with detected stenosis in 2 or more arteries (CAD) and healthy ones without stenosis in the arteries. Next, blood was taken to study circulating monocytes. Monocyte subpopulations were detected by flow cytometry from the leukocyte fraction using antibodies against CD14- FITC and CD16-PB450-A. Immediately after isolation, monocytes were stimulated with LPS with a final concentration of 1 ug/mL, and a supernatant was selected 24 hours later for further enzyme immunoassay. The inflammatory response was assessed by the secretion of cytokines TNFα, IL-1β, IL-6, IL-8, IL-10, and CCL2 using ELISA. The monocytes of CAD patients had an altered inflammatory response in response to LPS stimulation compared to patients without CAD. This was manifested in increased secretion of IL-1β and TNF, and decreased secretion of CCL2 and IL-6. An increase in the number of intermediate and non-classical monocytes in patients with CAD was associated with changes in the inflammatory response of cells to the secretion of cytokines IL-1β and CCL2. It can be assumed that pathological changes in the representation of monocyte subpopulations in the bloodstream may be one of the causes of chronic inflammation in the walls of the arteries, contributing to the progression of atherosclerotic lesions.