Background: The hemostasis system has been extensively investigated in patients in the acute phase of coronavirus disease 2019 (COVID-19). In contrast, the post-COVID syndrome is a poorly known entity, and there is a lack of information on the mechanisms underlying the hemostasis abnormalities in the post-COVID period. Aim: To analyze the potential changes in the parameters of the hemostasis system in the post-COVID period in the plasma of donors with different titers of anti-SARS-CoV-2 IgG. Methods: The plasma from 160 donors who had recovered from COVID infection was used in the study. Based on the results of the Abbott SARS-CoV-2 IgG serological assay, all donors were divided into several groups: 5 ± 3 (n=20); 55 ± 5 (n=20); 65 ± 5 (n=20); 75 ± 5 (n=20); 85 ± 5 (n=20); 95 ± 5 (n=20); 125 ± 5 (n=20); 175 ± 5 (n=20) Index (S/C). A total of 20 healthy individuals without anti-SARS-CoV-2 IgG constituted the control group. Key laboratory parameters, such as fibrinogen concentrations, soluble fibrin monomer complex (SFMCs), and D-dimer, were investigated. In addition, the qualitative composition of the fraction of SFMCs was analyzed. Results: The slight increase in the concentration of fibrinogen, SFMCs, and D-dimers in some donor groups have been found, which could cause the development of hemostasis disorders. In the fraction of SFMCs, the increase in the number of protein fragments with a molecular weight of less than 250 kDa and an increase in the level of proteins with a molecular weight of more than 270 kDa was revealed. Conclusion: The obtained results indicated the relationship between the changes in the parameters of the hemostasis system and the titers of anti-SARS-CoV-2 IgG in donors in the post-COVID period. It can be assumed that donors with higher titers of anti-SARS-CoV-2 IgG (>55 ± 5 Index (S/C)) are more prone to hemostasis abnormalities in the post-COVID period since a pronounced imbalance in the levels of SFMCs and D-dimer characterizes them. The appearance of protein fragments of different molecular weights in the fraction of SFMC points to uncontrolled activation of biochemical processes involving molecules of fibrinogenic origin. Additional studies are required to elucidate the role of anti-SARS-CoV-2 IgG in the post-COVID period.

The fibrinolytic system plays an important role in controlling blood coagulation at each stage, from thrombin generation to fibrin clot cleavage. Currently, long-term multiorgan dysfunction post-coronavirus disease 2019 (COVID-19) may include coagulation disorders. Little information is available about the potential causes of post-COVID-19 coagulopathy, but one of them may be subpopulation IgG produced by the immune system against SARS-CoV-2. This article describes the changes in the main parameters of the fibrinolytic system in donors with various titers of anti-SARS-CoV-2 IgG, which is part of a complex study of the hemostasis system in these donor groups. We determined the most significant parameters of the fibrinolytic system, such as potential activity and amount of plasminogen and tissue plasminogen activator (tPA), amount of plasminogen activator inhibitor-1 (PAI-1), inhibitory potentials of α-2-antiplasmin, α-1-antitrypsin, α-2-macroglobulin in the blood plasma of donor groups. The obtained results represent the maximum and minimum values of measurement parameters among donor groups with titers of anti-SARS-CoV-2 IgG at least 10 ± 3 Index (S/C), and their statistical differences from the reference point [donor group with titer of anti-SARS-CoV-2 IgG 0 Index (S/C)]. We established the changes in fibrinolytic parameters depending on the titers of anti-SARS-CoV-2 IgG. One conclusion can be drawn from this: anti-SARS-CoV-2 IgG population may influence coagulation in the post-COVID-19 period. Further research in-vitro and in-vivo experimental models using selected and purified IgG may confirm our previous findings.

COVID-19 differs from other respiratory diseases in that it can cause an acute inflammatory reaction following widespread systemic complications in organisms. First, the inflammatory process causes an increase in the concentration of C-reactive protein (CRP), which could be a prognostic biomarker in patients with COVID-19. In addition, some clinical data were used to determine changes in the concentrations of ferritin and transferrin. Our study aimed to establish a relationship between the inflammatory process and iron-dependent parameters, as changes in concentration could lead to pathological status in the post-COVID-19 period. People suffered from COVID-19 with different titers of anti-SARS-CoV-2 IgG in the blood participated in our experiment. It was established that the maximal concentration of CRP and ferritin was characterized for the donor group with a titer of anti-SARS-CoV-2 IgG 95 ± 5 Index (S/C) following the development of inflammatory anemia. Moreover, it was discovered that the group with a minimal titer of anti-SARS-CoV-2 IgG was characterized by the maximal concentration of transferrin, leading to the destruction of iron transport. Due to the acute inflammatory process and damage to the transport and storage of iron by transferrin and ferritin, the iron deficit could destroy the functioning of the muscle system. There was a change in the concentration of creatine kinase in the donor group with a titer of anti-SARS-CoV-2 IgG of 95 ± 5 Index (S/C). The study showed that infection with the SARS-CoV-2 virus in the body often leads to the development of acute inflammatory reactions, resulting in iron transport and storage processes, which cause pathological processes in the post-COVID-19 period.

The COVID-19 pandemic started at the end of 2019 in China. It is spreading to all continents in a few months and continuing to this day. It shows a serious threat to the healthcare system around the world, because it is necessary to provide intensive care to a previously unthinkable number of patients. Although SARS-CoV-2 causes damage to the respiratory system, research shows that COVID-19 is a hidden enemy for our body, as a result of which other organs also suffer, in particular the liver. In the literature, over a short period of the pandemic, little scientific information has accumulated regarding changes in the biochemical parameters of the liver during the development of COVID-19. Our study focused on the clinical diagnosis of patients suffering from hepatitis B and infected with SARS-CoV-2, additionally, a study was conducted of persons suffering from COVID-19 and patients with the development of hepatitis B, and a comparison of the study groups was carried out to identify relationships. links between SARSCoV- 2 infection and HBV progression. We found that in patients with hepatitis B with SARS-CoV-2 coinfection, significant deviations from the physiological norm of such parameters of liver functioning as ALT, AST, total and direct bilirubin, were observed, however, such indicators as GGT were in the limit values of the norm. and alkaline phosphatase. Our study demonstrates the need for careful monitoring of patients with hepatitis B with SARS-CoV-2 coinfection, and it is also recommended to conduct additional clinical diagnosis of such groups of patients to identify other parameters of pathological conditions and to improve diagnostic/treatment approaches in high-risk groups of patients infected with SARS-CoV-2.

The problem of obesity in modern life is becoming more actual and is a serious social risk for human life. This problem is common despite social and professional affiliation, location, age and gender. Obesity is associated with an increase growth of adipose tissue. Today obesity isn't studied only as an excessive accumulation of fat in the body, but as a chronic multivariate disease associated with a number of serious metabolic, oncological, cardiological and other complications. Although a lot of research studies regulation and intracellular processes of adipogenesis, however the information about molecular mechanisms of remodeling of the extracellular matrix during an increase fat mass is limited. Matrix metalloproteinases (MMPs) can increase the plasticity of the matrix, thereby providing adipose tissue remodeling and / or adipocyte hypertrophy, play an additional role in the growth of adipose tissue associated with obesity, supporting the differentiation of adipose tissue progenitor cells. Our research is aimed at characterization of enzymatic activitiesof MMPs in adipose tissue of the rats with obesity. We found that active enzymes with a molecular weight > 100 kDa were found in the adipose tissue of rats for the development of obesity, which may result from the formation of homodimers in these pathological conditions.Also activities of the MMP-2, -9 increase during obesity. Future studies of enzymatic activity of MMPs of rat's adipocytes tissues will improve understanding the biochemical processes under the conditions of this pathology and development of new approaches to diagnosis and treatment of obesity principles.