| Abstract [eng] |
The data presented in this work could be important in better understanding relationship between oxidative stress from one side and formation of endothelial microvesicles (EMVs), from the other, in early atherosclerosis environment. Associations between atherosclerosis risk factors and oxidative stress marker (malondialdehyde) and the total counts of microvesicles and exosomes found in this work are important for future clinical research. The research objective was to detect and investigate endothelial and platelet-derived microvesicles and exosomes in healthy young (25-39 years old), healthy elder (40-60 years old) and post-myocardial infarction (MI) (40-60 years old) male populations and show their association with atherosclerosis risk factors and oxidative stress. 81 healthy individuals were examined between December 2015 and July 2017 and included in the work. Healthy subjects had no prior history of acute cardiovascular disease and were not under any treatment for cardiovascular diseases. All subjects were males 25 to 60 years old. The test group also included fifteen patients. They have been treated for MI in the cardiac intensive care unit, intensive care unit and first cardiology ward of Vilnius University Hospital Santaros Clinics three months before the inclusion. Patients were enrolled later in the work than healthy subjects - between February and May of 2018. All of them were aged 40 to 60 years old. Patients had myocardial infarction for the first time in their life and coronary angiography confirmed coronary occlusion of more than 50 % in at least two arteries. Coronary catheterization and coronary angioplasty were performed on all patients. Four different populations of endothelial microvesicles were detected: 1) containing CD105 and without CD42a and CD61; 2) containing CD31 and without CD42a and CD61; 3) containing CD144 and without CD42a and CD61; 4) containing CD144 and CD42a and without CD61. Each subpopulation had one endothelial cell marker CD105 (endoglin), CD144 (VE-cadherin) or CD31 (PECAM) that could reflect their function according to the association with the marker. CD62e was used as an activation marker of human blood endothelial microvesicles. The healthy younger group had a significantly elevated amount of VE-cadherin-EMVs when compared with other groups. The healthy elder group and post-MI group had median differences in all EMVs populations except for VE-cadherin without thrombocytic marker: The highest amounts of PECAM EMVs were detected in the healthy elder group, a lower amount in the post-MI group, and the lowest in the healthy younger group. Looking at endoglin-EMVs, the highest amount was detected in the post-MI group and the lowest in the healthy elder group. This shows a definitive link to the PECAM-EMVs since the results are reversed in the case of endoglin-EMVs. When comparing CD62e expression on the EMV membrane between healthy individuals and MI patients, all EMV populations differently expressed CD62e. Endoglin-EMVs had a much higher activation level in the post-MI group when compared with other populations of EMVs. The concentration of malondialdehyde was associated with an increase in the total number of endothelial microvesicles and exosome in the healthy group. Activated (i.e. carrying E-selectin) endoglin- endothelial microvesicles had a positive association with malondialdehyde concentration and a strong negative association with high-density lipoprotein cholesterol concentration in healthy subjects. In the post-MI group, these activated endothelial microvesicles were negatively associated with total cholesterol or low-density lipoprotein cholesterol concentrations. There was a clear difference between endoglin and VE-cadherin containing endothelial microvesicles comparing correlation data between their numbers and malondialdehyde or cholesterol concentrations. The increased number of endothelial microvesicles detected in the elder healthy group in comparison to the younger healthy group could mean an association of endothelial microvesicles numbers with pathological processes in the endothelium could be possible. Association between numbers and activation levels of endothelial microvesicles and concentration of high-density lipoprotein cholesterol in the blood was observed in both post-MI and the healthy elder group. These VE-cadherin and endoglin containing endothelial microvesicles could be related to the degeneration processes of the endothelial tissue. Another microvesicle group investigated in this work was platelet microvesicles. The difference in the total number of platelet microvesicles between groups was not detected. The ratios between endothelial microvesicles and platelet microvesicles were more interesting. Statistically significant differences were observed especially when ratio with VE-cadherin-containing endothelial microvesicles containing the CD42a was investigated. This ratio (between total numbers of VE-cadherin-containing endothelial microvesicles with the CD42a and platelet microvesicles) had a negative association with malondialdehyde concentration. This association with malondialdehyde concentration not only serves to prove the possible negative effect of VE-cadherin endothelial microvesicles but also introduces platelet microvesicles as a possible effector in oxidative stress. In this work, nanoparticle tracking analysis showed lower amounts of exosomes in the post-myocardial infarction patients. The same result was detected when investigating microvesicles. Thioredoxin was also detected in exosomal samples. Detection of thioredoxin and association between malondialdehyde concentration and the number of exosomes could show their possible involvement in oxidative stress and subsequent endothelium damage. Data of this work show the involvement of ECVs both small and large (exosomes and microvesicles) in oxidative stress and ultimately in the pathogenesis of atherosclerosis. |
