Age-related Сhanges of Diameter and Deformability of Red Blood Cells

Іntroduction. The diameter and deformability of red blood cells (RBCs) play a very important role in the maintenance of normal blood flow in the microcirculation. RBCs deformability has been described based on three physical properties: membrane viscoelastic properties, the internal viscosity and the surface area-to-volume ratio. The membrane properties and thus the deformability of RBCs are largely detailed and considerable information is available regarding the skeleton composition, ultrastructures, protein- to-protein interactions, membrane anchorage, and molecular defects. The aim of the research was to study the age-related changes of diameter and deformability of RBCs in practically healthy volunteers. Materials and methods. Morphological and biophysical parameters (diameter, deformability) of RBCs were studied in 50 practically healthy men – volunteers. They were divided into two age groups: adults (22-30 years old, 25), and old people (75-89 years old, 25). For a morphological research were made smears, which were dyed by Sudan Black according to the method of F. A. McManus. Diameter of erythrocytes was measured with the ocular micrometer. The deformability of erythrocytes was determined with the help of the computer filter-photometer method. The time of the diffusion on the filter paper was determined for this pattern. Statistic processing of obtained results was conducted according to the program SPSS, version 11.0. Student's t-test was used for analysis of differences between means and a change with a p < 0.05 was considered statistically significant. Results. RBC ageing is closely related to a progressive decrease in ADP/ATP ratio, which provides disorders of osmotic balance, cells' swelling, activating signal transduction system, which affects properties regulating RBC deformability and finally leads to the removal of old cells from the circulation by macrophages at spleen level. It was shown that the number of the RBCs that passed the filter paper per time unit in old people is statistically significantly low compared to the young people. So there is a tendency of the increase of the diameter of RBCs in aged people, this indicates that the volume of erythrocytes is increased in old people. Conclusions. The excessive number of large-sized matured (aged) erythrocytes is revealed in the blood of old people. Different rheological characteristics of RBCs in various aged volunteers have as a result the aged-related cardiovascular diseases.