Changes in the proteomics of exhaled breath condensate under the influence of inhaled hydrogen in patients with post-COVID syndrome.

Aim. To study the effect of inhalation therapy with an active hydrogen (AH) on the protein composition of exhaled breath condensate (EBC) in patients with post-COVID syndrome (PCS). Material and methods. This randomized controlled parallel prospective study included 60 patients after coronavirus disease 2019 (COVID-19) with PCS during the recovery period and clinical manifestations of chronic fatigue syndrome who received standard therapy according to the protocol for managing patients with chronic fatigue syndrome (CFS). The patients were divided into 2 groups: group 1 (main) - 30 people who received standard therapy and AH inhalations (SUISONIA, Japan) for 10 days, and group 2 (control) - 30 medical workers who received only standard therapy. Patients in both groups were comparable in sex and mean age. All participants in the study were sampled with EBC on days 1 and 10. Samples were subjected to tryptic digestion and high-performance liquid chromatography combined with tandem mass spectrometry analysis using a nanoflow chromatograph (Dionex 3000) in tandem with a high-resolution time-of-flight mass spectrometer (timsTOF Pro). Results. A total of 478 proteins and 1350 peptides were identified using high resolution mass spectrometry. The number of proteins in samples after AH therapy, on average, is 12% more than before treatment. An analysis of the distribution of proteins in different groups of patients showed that only half of these proteins (112) are common for all groups of samples and are detected in EBC before, after, and regardless of hydrogen therapy. In addition to the qualitative difference in the EBC protein compositions in different groups, quantitative changes in the concentration of 36 proteins (mainly structural and protective) were also revealed, which together made it possible to reliably distinguish between subgroups before and after treatment. It is worth noting that among these proteins there are participants of blood coagulation (alpha-1-antitrypsin), chemokine- and cytokine-mediated inflammation, and a number of signaling pathways (cytoplasmic actin 2), response to oxidative stress (thioredoxin), glycolysis (glyceraldehyde-3- phosphate dehydrogenase), etc. Conclusion. The use of hydrogen therapy can contribute to the switching of a number of physiological processes, which may affect the success of recovery in PCS patients. In particular, the obtained results indicate the activation of aerobic synthesis of adenosine triphosphate in mitochondria by hydrogen therapy, which correlates well with the decrease in the blood lactate level detected by laboratory studies. At the same time, this therapy can inhibit pro-inflammatory activity, negatively affecting the coagulation and signaling pathways of integrins and apoptosis, and, in addition, activate protective pathways, tricarboxylic acid cycle, FAS signaling, and purine metabolism, which may be essential for effective recovery after COVID-19.Copyright © 2023 Vserossiiskoe Obshchestvo Kardiologov. All rights reserved.

[Comparative study of Wuhan-like and omicron-like variants of SARS-CoV-2 in experimental animal models].

INTRODUCTION: The variability of SARS-CoV-2 appeared to be higher than expected, the emergence of new variants raises concerns. The aim of the work was to compare the pathogenicity of the Wuhan and BA.1.1/Omicron variants in BALB/c mice and Syrian hamsters. MATERIALS AND METHODS: The study used strains of SARS-CoV-2: Dubrovka phylogenetically close to Wuhan-Hu-1, and LIA phylogenetically close to Omicron, BALB/c mice, transgenic mice B6.Cg-Tg(K18-ACE2)2Prlmn/HEMI Hemizygous for Tg(K18-ACE2)2Prlmn, Syrian golden hamsters. Animals were infected intranasally, pathogenicity was estimated by a complex of clinical, pathomorphological and virological methods. RESULTS: Comparative studies of SARS-CoV-2 Dubrovka and LIA strains on animal models demonstrated their heterogeneous pathogenicity. In parallel infection of BALB/c mice with Dubrovka and LIA variants, the infection proceeded without serious clinical signs and lung damage. Infection with the LIA strain resulted to a systemic disease with a high concentration of viral RNA in the lungs and brain tissues of animals. The presence of viral RNA in mice infected with the Dubrovka strain was transient and undetectable in the lungs by day 7 post-infection. Unlike the mouse model, in hamsters, the Dubrovka strain had a greater pathogenicity than the LIA strain. In hamsters infected with the Dubrovka strain lung lesions were more significant, and the virus spread through organs, in particular in brain tissue, was observed. In hamsters infected with the LIA strain virus was not detected in brain tissue. CONCLUSION: The study of various variants of SARS-CoV-2 in species initially unsusceptible to SARS-CoV-2 infection is important for monitoring zoonotic reservoirs that increase the risk of spread of new variants in humans.

Bacterial ligands in the rehabilitation of healthcare workers after COVID-19

Immune defense mechanisms in survivors of the COronaVIrus Disease-19 (COVID-19) and development of their rehabilitation during the pandemic both portray a great scientific and practical interest. The aim of the study was to explore effect of Immunovac-VP-4 (I-VP-4), a vaccine based on bacterial ligands, on the clinical and airway mucosal immunity parameters, along with systemic immune response in a group of medical workers in post-COVID period and in persons who did not develop the disease. Methods. 82 healthcare workers aged from 18 to 65 years were included in a prospective open controlled study. The participants were divided into 4 groups: groups 1 (n = 20) and 2 (n = 27) included those with a history of COVID-19, and groups 3 (n = 18) and 4 (n = 17) included those who did not have the disease. Volunteers in groups 1 and 3 received I-VP-4. Samples of oral fluid, induced sputum, nasopharyngeal and oropharyngeal mucosa scrapings, and venous blood were examined. The levels of total secretory immunoglobulin class A (sIgA) and immunoglobulin G (IgG) were determined by enzyme immunoassay. The phagocytic index (PI) of leukocytes was assessed by flow cytometry. Results. The group of patients who did not have COVID-19 and received IVP-4 (Group 3) showed a tendency to a smaller number of COVID-19 cases, as well as some reduction in days of incapacity for work due to the acute respiratory infections (ARI). The vaccine improved airway mucosal immunity parameters and innate immune response. sIgA increased in the induced sputum (p < 0.005) and unchanged in the oropharyngeal mucosa samples in Group 1. The PI of macrophages in oral fluid doubled (p < 0.05) in this group. At the same time, those parameters decreased in Group 2. In non-infected vaccinated patients (Group 3), a significant increase of PI of blood monocytes was found on the day 90 of the study (p < 0.05). Also, a four-fold increase of PI of macrophages in oral fluid in comparison with Group 4 (p < 0.05) was noted. Conclusion. I-VP-4 improved airway mucosal immunity mechanisms and the systemic immune response. The vaccine can be recommended for rehabilitation programs for COVID-19 survivors and for prevention of ARIs. Copyright © 2022 Medical Education. All rights reserved.

Biological characterization of cold-adapted SARS-CoV-2 variants

Introduction. The emergence of new epidemiologically significant variants of SARS-CoV-2 has shifted emphasis to development of a live vaccine, which would be able to provide protection against a wide range of antigenic variants of the virus. The aim of the study was to obtain SARS-CoV-2 variants attenuated through cold adaptation and to provide their biological characterization. Materials and methods. The Dubrovka laboratory strain of SARS-CoV-2 and its variants were cultured on Vero and Calu-3 cells. The virus quantification was performed by virus titration in Vero cells and by real-time reverse transcription-polymerase chain reaction. SARS-CoV-2 virions were analyzed using transmission electron microscopy. Genome sequences of the virus were identified by nanopore sequencing. The attenuation (att) phenotype of SARS-CoV-2 variants was identified using Syrian hamsters as an animal model for COVID-19. Results. Cold-adapted (ca) SARS-CoV-2 variants – Dubrovka-ca-B4 and Dubrovka-ca-D2 were produced by continued passaging of the Dubrovka strain in the Vero cell culture at the temperature being gradually decreased to 23ºC and by subsequent cloning. Up to 20 nucleotide substitutions and 18 amino acid substitutions were detected in genomes of ca-variants. Ca-variants, as distinct from the parent Dubrovka strain, actively replicated at 23ºC, while the Dubrovka-ca-D2 variant had a temperature-sensitive (ts) phenotype (did not replicate at 39ºC). Ca-variants of the virus replicated poorly at 37ºC in the Calu-3 human lung cell culture, which, along with the ts-phenotype, can be a marker of virus attenuation for humans. In the intranasally infected Syrian hamsters, ca-variants of the virus demonstrated an attenuation phenotype: they did not cause loss of appetite, fatigue, drowsiness, did not slow down weight gain, replicating much more slowly in the lungs and brain compared to the virulent Dubrovka strain. Conclusion. The obtained attenuated SARS-CoV-2 ca-variants, Dubrovka-ca-B4 and Dubrovka-ca-D2, should be studied further as candidate vaccine strains for a live attenuated vaccine against COVID-19. © Team of authors, 2022.

Immunogenic properties of SARS-CoV-2 inactivated by ultraviolet light.

Vaccination against COVID-19 is the most effective method of controlling the spread of SARS-CoV-2 and reducing mortality from this disease. The development of vaccines with high protective activity against a wide range of SARS-CoV-2 antigenic variants remains relevant. In this regard, evaluation of the effectiveness of physical methods of virus inactivation, such as ultraviolet irradiation (UV) of the virus stock, remains relevant. This study demonstrates that the UV treatment of SARS-CoV-2 completely inactivates its infectivity while preserving its morphology, antigenic properties, and ability to induce the production of virus-neutralizing antibodies in mice through immunization. Thus, the UV inactivation of SARS-CoV-2 makes it possible to obtain viral material similar in its antigenic and immunogenic properties to the native antigen, which can be used both for the development of diagnostic test systems and for the development of an inactivated vaccine against COVID-19.

Antimicrobial Activity of the Serum before and after Vaccination with EpiVacCorona.

We evaluated the effect of vaccination with anti-COVID-19 vaccine EpiVacCorona on serum antimicrobial activity, formation of specific IgG antibodies, and expression of some antimicrobial peptides. Antimicrobial activity of the serum from 55 volunteers towards S. aureus cells was measured spectrophotometrically; IgG-antibodies against SARS-CoV-2 antigen were assayed by ELISA; expression of genes encoding antimicrobial peptides LL37, HBD1, and HBD2 was evaluated by PCR with reverse transcription. Total antimicrobial serum activity and activity of its low-molecular-weight fraction containing antimicrobial peptides demonstrated an inverse correlation. Both activities after vaccination increased in case of low initial values, but decreased in case of high initial values. The vector of change of specific IgG antibodies to coronavirus inversely correlated with the vector of change of activity of antimicrobial peptide fraction. The expression of genes of antimicrobial peptides LL37, HBD1, and HBD2 looked like normal distribution depending on activities of the antimicrobial peptides in the corresponding sera.

[Hydrogen effect on the mechanisms of mucosal immunity in patients with COVID-19].

AIM: To study the inhalation of an active form of hydrogen effect to mucosal and system immunity in a rehabilitation program for health workers. MATERIALS AND METHODS: The study involved patients that survived COVID-19 after therapy with inhaled hydrogen for 90 minutes (n=30), and a control group of patients treated according to standard protocol for managing patients that survived COVID-19 during the rehabilitation period (n=30). Biomaterial was carried out in 2 stages: on the first day of the study, before the accepted therapy and on the 10th day of the study. The indicators of humoral and cellular immunity were studied. The levels of secretory immunoglobulin A (sIgA) and IgG were investigated using the method of enzyme-linked immunosorbent assay. Phagocytosis was assessed on a Beckman Coulter FC-500 flow cytometer. Statistical data processing was carried out in the GraphPad Prism 7.00 software using nonparametric methods. RESULTS: It was shown that the phagocytic index (PI) of monocytes in nasal scrapings after inhaled hydrogen treatment did not significantly change relative to the first day of treatment and control, while the PI of granulocytes in nasal scrapings significantly increased relative to the first day by 2.5 times (p=0.000189), as well as relative to the control by 1.1 times (p=0.047410). PI of monocytes in pharyngeal scrapings showed a significant increase relative to the first day of treatment by 2.8 times (p=0.041103), however, did not differ relative to the control. PI of granulocytes of pharyngeal scraping did not differ significantly relative to the first day and control. PI of granulocytes and blood monocytes of the studied group did not change significantly. PI of granulocytes and monocytes of peripheral blood relative to control during therapy did not change. The sIgA level in nasal scrapings significantly increased by 2.9 times, while in pharyngeal scrapings the level of sIgA significantly decreased by 2 times. Сonclusion. We have shown an increase in granulocytes PI in the nasal cavity and oral monocytes, as well as in the level of sIgA in the nasal cavity during therapy with active hydrogen. The data obtained indicate the effectiveness of therapy, which can be used both in the treatment of COVID-19, and in post-COVID syndrome as an additional therapy. The absence of changes in blood parameters, as well as individual links in nasal and pharyngeal scrapings, requires further study to develop ways to overcome treatment tolerance.

[Biological activity of interferons in the novel coronavirus infection COVID-19].

INTRODUCTION: The immunopathogenesis of the novel coronavirus infection COVID-19 is usually associated with the development of imbalance in the immune response to its causative agent, SARS-CoV-2 virus (Coronaviridae: Coronavirinae: Betacoronavirus: Sarbecovirus). This is manifested, in particular, by interferons' (IFNs) deficiency at the beginning of the disease followed by hyperproduction of pro-inflammatory cytokines. The virus causes a decrease in IFN types I (α/ß) and III (λ) levels; changes in IFN type II (γ) are less studied. In this regard, it is relevant to assess the functional bioactive IFN (interferon status) in COVID-19. The aim of the study was to assess the antiviral potential of the body by testing the biologically active IFNs in COVID-19. MATERIAL AND METHODS: We used biological serum samples of COVID-19 patients taken in the acute phase (110 patients on the 1-5 days of the disease) and during rehabilitation (47 patients during 1-3 months after the disease onset). Assessment of interferon status was performed according to the technique developed by the authors and described earlier. RESULTS: The IFN status of patients with COVID-19 in the acute period and in the phase of post-infection rehabilitation was studied вduring the observation period. It was found that SARS-CoV-2 causes a pronounced inhibition of biological activity of IFN types I and II compared to the reference values by more than 20 and 7 times, respectively. During the post-COVID period, incomplete recovery of the IFN system activity was registered, which proceeded very slowly. No cases of reaching physiological indicators of interferon status were identified during the observation period. CONCLUSION: The obtained data on deficiency of the functional biologically active IFN confirm the hypothesis about the predominant role of impaired IFN production of different types in the immunopathogenesis of the novel coronavirus infection.

Features of innate and adaptive immunity for infections with RNA-containing respiratory viruses

During respiratory infections caused by RNA-containing viruses, double-stranded (ds) replicative forms bind with specific receptors in the endosomes and cytosol of infected cells. Therefore, the induction of gene expression of early cytokines occurs faster and more efficiently dsRNA. Induction of innate and specific adaptive immunity usually provides complete eradication of extracellular virions and infected cells without chronic infection and risk of recombination between viral RNA and host cell chromosomes due to absence of DNA copies of the virus genomes. However, this increases the risk of a cytokine storm with pathological disorders of defense systems. Mutual adaptation of viruses and their hosts includes interaction of viral antigens with host cytokines or corresponding receptors that results in disturbances of the fist line of host defense and infection progression.

Potential of application of the RNA interference phenomenon in the treatment of new coronavirus infection COVID-19.

COVID-19 has killed more than 4 million people to date and is the most significant global health problem. The first recorded case of COVID-19 had been noted in Wuhan, China in December 2019, and already on March 11, 2020, World Health Organization declared a pandemic due to the rapid spread of this infection. In addition to the damage to the respiratory system, SARS-CoV-2 is capable of causing severe complications that can affect almost all organ systems. Due to the insufficient effectiveness of the COVID-19 therapy, there is an urgent need to develop effective specific medicines. Among the known approaches to the creation of antiviral drugs, a very promising direction is the development of drugs whose action is mediated by the mechanism of RNA interference (RNAi). A small interfering RNA (siRNA) molecule suppresses the expression of a target gene in this regulatory pathway. The phenomenon of RNAi makes it possible to quickly create a whole series of highly effective antiviral drugs, if the matrix RNA (mRNA) sequence of the target viral protein is known. This review examines the possibility of clinical application of siRNAs aimed at suppressing reproduction of the SARS-CoV-2, taking into account the experience of similar studies using SARS-CoV and MERS-CoV infection models. It is important to remember that the effectiveness of siRNA molecules targeting viral genes may decrease due to the formation of viral resistance. In this regard, the design of siRNAs targeting the cellular factors necessary for the reproduction of SARS-CoV-2 deserves special attention.

Immune mechanisms of SARS-CoV-2 and potential drugs in the prevention and treatment of COVID-19

The lack of specific vaccines against SARS-CoV-2, as well as chemotherapy, significantly affected the spread of infection and the number of adverse outcomes of COVID-19. With the discovery of the pathogenesis of coronavirus infection, especially immune mechanisms, the important role of the innate immunity system in interacting with the virus is obvious. The presence of comorbid conditions, as well as the aging of the body, lead to disturbances in the immune response mechanism, low interferon induction, depletion of CD8+-lymphocytes and natural killers and suppression of the effectiveness of both innate and adaptive immunity. The review discusses various mechanisms of antiviral activity associated with the induction of interferon (IFN) production, the use of direct IFN therapy, the use of antiviral drugs, and immunotropic therapy (synthetic immunomodulators), as promising in the prevention and treatment of COVID-19. © 2020 Medical Education. All rights reserved.