Immunohistochemistry Data on the Structural and Functional Changes in the Vascular Endothelium of the Heart of Old Rats

The goal of the study was to investigate the morphofunctional changes of the vascular endothelium in different parts of the heart of aging rats with the immunohistochemical detection of von Willebrand factor (vWF). Reactive, dystrophic, and pathological changes in endotheliocytes (ECs) in different parts of the heart of old (18–23 months) rats were identified for the first time with an immunohistochemical marker, vWF. They were most strongly expressed in the endothelium of the arterial vessels of the aortic root, the coronary arteries of the epicardium, and the sinusoidal and true capillaries of atrial and ventricular myocardium. The desquamation of ECs in the blood, the death of myocardial capillaries, an increase in the number of sinusoidal vessels and their mummification, and the formation of lacunae or cisterns filled with blood were observed. It was found that the secretory activity of ECs, along with morphological changes, abruptly increases with aging. It was demonstrated that many products of the protein metabolism, pigment, Weibel–Palade bodies, and blood clots of various sizes accumulate in the cavity of subaortic conus of the heart in old rats. Pigment structures were also been seen in the valves and the fibrous ring. The data are of great diagnostic value and indicate a high probability of risk factors and possible premature lethality.