Role of type IV collagen and matrix metalloproteinase-9 in remodeling of the left ventricular in coronary artery disease

Currently, the analysis of the fibrosis severity during the restructuring of the surrounding extracellular matrix (ECM) is studied in most of the research works devoted to “cardiac remodeling”. At the same time, the role of the basal membrane of cardiomyocytes in heart diseases was not studied. The basal membrane of cardiomyocytes is a highly organized layer of the ECM which is located on the outer side of the sarcolemma. Degradation of ECM components is carried out by different types of matrix metalloproteinases (MMP), which have proteolytic activity and are actively involved in the process of ECM remodeling, destroying its components such as collagen, elastin, fibronectin, glycosaminoglycans and other structural components. Aim. To evaluate the ECM status in patients with coronary artery disease and its effect on left ventricular myocardial remodeling. Material and methods. Morphological and immunohistochemical (IHC) examination of left ventricular myocardial biopsies was performed in 16 patients undergoing left ventricular reconstruction in combination with coronary artery bypass grafting. Results. The IHC study revealed the accumulation of matrix metalloproteinase-9 in the cytoplasm of cardiomyocytes. This accumulation was combined with partial or complete destruction of the basal membranes (BM) of cardiomyocytes formed by type IV collagen. Conclusion. Type IV collagen destruction in basal membranes of left ventricular cardiomyocyteswasrevealed. It iscausedbytheactionofmatrixmetalloproteinase-9, which accumulates in the cell cytoplasm.