Ultrastructural Blood Cell Changes in Patients with COVID-19

Abstract

Introduction:: Nowadays, the coronavirus disease COVID-19 is a global problem for the population of the whole world which has acquired the character of a pandemic. Under physiological conditions, in a healthy person, erythrocytes make up 96 % of all blood cells, leukocytes 3 %, and thrombocytes about 1 %. In healthy individuals, erythrocytes are mostly shaped like a biconcave disc and do not contain a nucleus. The diameter of the erythrocyte is 8 microns, but the peculiarities of the cell structure and the membrane structure ensure their great ability to deform and pass through capillaries with a narrow lumen of 2-3 microns. Therefore, the study of the morpho-functional state of blood cells, namely erythrocytes, in this category of patients is relevant and deserves further research. The Aim: To figure out the effect of the coronavirus disease COVID-19 on the ultrastructural blood cell changes, in particular erythrocytes, in patients with ischemic heart disease (IHD) and diabetes mellitus type 2. Materials and Methods: Twelve patients with COVID-19 who had an acute myocardial infarction were examined. The comparison group consisted of 10 people with acute myocardial infarction without symptoms of COVID-19. The average age of the patients was 62 ± 5,6 years. The functional state and ultrastructure of blood cells were studied using electron microscopy. Results:: In the presence of COVID-19, we detected both calcification and destruction of erythrocytes and platelets. Reticulocytes were detected much more often in these individuals than in the comparison group. In patients with acute myocardial infarction in the presence of type 2 diabetes and COVID-19, a significant number of markedly deformed, hemolyzed erythrocytes or with signs of acanthosis, which stuck together and with other destructively changed blood cells, were found. We also detected «neutrophils extracellular traps» (NETs). Conclusions:: Morphological changes of blood cells in COVID-19 varied according to the disease course and severity especially in the background of a weakened immune system in older and elderly people, in the presence of diabetes, excessive body weight, cardiovascular diseases and occupational hazards. Under the influence of COVID-19, blood cells are destroyed by apoptosis and necrosis. Therefore, hypoxia and ischemia of vital organs of the human body occur.