Structural and molecular markers of aging heart: Sechenov University classification

Abstract Background The process of aging at the level of the cells is connecting with arising of senescence cell, that are characterized by several possible signs, including damage to the mitochondria and contraction of telomeres, epigenetic changes, impaired regulation of protein metabolism, sensitivity to nutrients, mitochondrial dysfunction, stem cell collapse, impaired intercellular communication. Postmitotic cells may also develop senescence and are called amitosenescence cells (AMCs). Goal To investigate structural and molecular characteristic of aging heart with special identification of AMCs and creating classification of aging heart status. Methods Study was performed on 52 biopsies (endomyocardial and operative) of the heart and 48 autopsy cases (38 women and 62 men) with diagnosis of dilated cardiomyopathies, chronic ischemic heart disease, hypertensive cardiomyopathies, rheumatic heart disease and their combination. All patients were divided in two groups according to the age of patients: 1 group included 80 patients (average age 72.9±13.3 years) and 2 control group - 20 patients (average age 42.9±13.3 years). Serial paraffin sections were stained with hematoxylin and eosin, picrofuchsin; p16ink, Apocas, CD68 and CD 45 were detected by immunohistochemistry (DakoCytomation). We have calculated percent of AMC, Apo and RCB in 30 fields of vision on X400 magnification. Results AMCs were found in the myocardium of 77 aging patients and only in 2 young patients (premature aging?). AMCs were characterized by prominent degenerative changes, p16ink expression and accumulation of lipofuscin. Reduction of capillary bad (RCB), increased number of apoptotic bodies and presence of CD68+ macrophages and CD45+ lymphocytes were found in stroma. There were three aging heart status degree: 1 – presence less than 15% of AMCs, 0,1% of Apo and RCB –less than 15% (20 patients); 2 – presence 16–30% of AMCs, 0,2- 1% of Apo and RCB – 16–30% (35); 3 – presence more than 31% of AMCs, 1–2% of Apo and RCB – more than 31% (27). Conclusion Aging heart has increased number of amitosenecence cells that results severity and chronicity of heart diseases in aging patients. Funding Acknowledgement Type of funding sources: None.