Phagocytic activity and proinflammatory activation potential of smooth muscle cells of the Tunica intima of human aorta under experimental conditions

The aorta is the largest blood vessel in the body, which reaches a diameter of about 3 cm and is responsible for transporting oxygen-enriched arterial blood from the heart to tissues and organs. The aortic wall consists of three layers: the inner Tunica intima, the middle Tunica media and the outer Tunica adventitia. The layers of the aortic wall have a diverse cellular composition and include smooth muscle cells (SMCs), fibroblasts, endothelial cells, etc. Functional disorders in the cells of the intima of the human aorta can lead to various cardiovascular diseases (СVD), such as aneurysm and, as a result, dissection or rupture of the thoracic aorta. The cellular and molecular mechanisms of CVD development remain not fully understood, therefore, the study of the functional characteristics of various cell populations that make up the human aorta is an urgent task today. The aim is to evaluate the inflammatory response formed by cells that are part of the Tunica intima of the human aorta during phagocytosis of latex particles and internalization of low-density lipoproteins (LDL) to study their role in the development of aneurysms. The experiments were performed on smooth muscle cells (SMCs) isolated from the intima of the human aorta in patients with aneurysm. Phagocytic activity was studied by adding latex beads to the SMCs of Tunica intima, the ability to internalize LDL was evaluated using the BDP 630/650 dye and a biochemical method, the assessment of the ability to pro- and anti-inflammatory activation was studied using enzyme-linked immunosorbent assay (ELISA). Our results demonstrated that the absorption of latex beads and LDL stimulates the activation of interleukin secretion by smooth muscle cells that are part of the Tunica intima of the aorta, namely the proinflammatory cytokines IL-6 and IL-8. This fact may indicate that in the conditions of the body, the human aortic intima SMCs phenotype may switch from contractile to secretory or macrophage-like, which indicates the participation of this phenotypic cell transition in the process of aneurysm development.