AGE-RELATED FEATURES OF MELATONIN RECEPTOR EXPRESSION IN THE CARDIOMYOCYTES OF PATIENTS WITH DILATED CARDIOMYOPATHY

To understand the pathogenesis of dilated cardiomyopathy (DCM), it is necessary to establish the molecular and cellular mechanisms of myocardial aging, including those associated with melatonin. The latter affects vascular tone, the binding of smooth muscle cells and vascular endothelium to their own receptors (melatonin receptor type 1A (MR1A), melatonin receptor 1B (MR1B)) and acts on the adrenergic and peptidergic (vasointestinal peptide and substance P) endings of perivascular nerves, which allows melatonin to be considered as an important predictor of the development of DCM. The molecular mechanisms of this interaction still remain insufficiently studied. Objective: to study MR1A and MR1V in the cardiomyocytes of patients with DCM in vitro. Methods. Primary dissociated cell cultures and immunofluorescence confocal laser scanning microscopy were used. Passages 3 and 10 cells corresponding to young and old cultures were applied to model cellular senescence. Results. At the molecular level, cardiomyocyte senescence was accompanied by a 3-fold decrease in the level of MR1B expression compared to the old cultures in both the control and the DCM groups (by 1.8 times). Furthermore, there was a 2-fold decrease in MR1A expression in the cell cultures taken from patients with DCM compared with the similar culture of normal cardiomyocytes. The expression of MR1B was significantly lower in the DCM group than that in the control group in passage 3. With aging in the cultures, the level of MR1B expression was significantly lower by 3.9 times in the DCMP group than that in the control group. The similar trends in the studied markers may suggest that both melatonin receptors are involved in the pathogenesis of DCM, which may also be involved in the mechanisms of aging. The findings will be able to expand the concept of DCM and to form its diagnostic panel in people of different ages.

geriatrics, cardiology, dilated cardiomyopathy, heart cellular senescence, melatonin receptors, cell culture, confocal microscopy