[Stochastic Packaging of Cas Proteins into Exosomes].

CRISPR/Cas systems are perspective molecular tools for targeted manipulation with genetic materials, such as gene editing, regulation of gene transcription, modification of epigenome etc. While CRISPR/Cas systems proved to be highly effective for correcting genetic disorders and treating infectious diseases and cancers in experimental settings, clinical translation of these results is hampered by the lack of efficient CRISPR/Cas delivery vehicles. Modern synthetic nanovehicles based on organic and inorganic polymers have many disadvantages, including toxicity issues, the lack of targeted delivery, and complex and expensive production pipelines. In turn, exosomes are secreted biological nanoparticles that exhibit high biocompatibility, physico-chemical stability, and the ability to cross biological barriers. Early clinical trials found no toxicity associated with exosome injections. In the recent years, exosomes have been considered as perspective delivery vehicles for CRISPR/Cas systems in vivo. The aim of this study was to analyze the efficacy of CRISPR/Cas stochastic packaging into exosomes for several human cell lines. Here, we show that Cas9 protein is effectively localized into the compartment of intracellular exosome biogenesis, but stochastic packaging of Cas9 into exosomes turns to be very low (~1%). As such, stochastic packaging of Cas9 protein is very ineffective and cannot be used for gene editing purposes. Developing novel tools and technologies for loading CRISPR/Cas systems into exosomes is needed.

[Pharmacoeconomic evaluation of the tixagevimab and cilgavimab combination using for pre-exposure prophylaxis of COVID-19].

AIM: To evaluate pharmacoeconomic feasibility using of the tixagevimab and cilgavimab combination for pre-exposure prophylaxis of COVID-19 in immunocompromised patients. MATERIALS AND METHODS: Cost-effectiveness of tixagevimab and cilgavimab in persons ≥12 years old who weigh ≥40 kg and have either a history of allergy that prevents their vaccination against COVID-19 or moderate or immunocompromised was assessed based on PROVENT phase III study results. The quantity of life years or quality-adjusted life years gained was calculated. Direct medical cost associated with prophylaxis of COVID-19, treatment of infected patients and those experiencing long COVID post infection were assessed. Results were compared with wiliness-to-pay threshold, measured as tripled gross domestic product per capita and equal to 2.69 mln RUB in 2022. RESULTS: Pre-exposure prophylaxis of COVID-19 results in additional 0.0287 life years or 0.0247 quality-adjusted life years. The cost of additional life year gained is equal to 1.12 mln RUB, the cost of additional quality-adjusted life years is 1.30 mln RUB. Both costs of additional life year and cost of quality-adjusted life years appeared to be significantly less compared to wiliness-to-pay threshold. CONCLUSION: Pre-exposure prophylaxis of COVID-19 with combination of tixagevimab and cilgavimab is economically feasible and may be recommended for wide use in Russian healthcare system.

[Use of a combination of the virus-neutralizing monoclonal antibodies casirivimab and imdevimab for mild to moderate COVID-19 in patients at high risk of progression: Results of the non-interventional observational study].

AIM: To evaluate the efficacy and safety of a combination of virus-neutralizing monoclonal antibodies - MAB (casirivimab and imdevimab) in patients with mild to moderate COVID-19 with risk factors in real word settings. MATERIALS AND METHODS: A non-interventional non-comparative observational study with primary prospective data collection included 108 patients with mild to moderate COVID-19 (mean age 61 years), who had risk factors for developing severe disease. All patients (n=108) were treated with a combination of MAB casirivimab and imdevimab intravenous single infusion 1200 mg (600 mg of each component). The efficacy and safety of MAB were assessed at 7, 14, and 28 days after infusion. RESULTS: Efficacy. Indications for hospitalization by day 7 from the moment of MAB administration were in 0.9% (n=1), by day 14 - in 1.9% (n=2), by day 28 - in 0.9% of patients; to stay in the intensive care units by the 7th day - in 4.6% (n=5), by the 14th day - in 0.9% (n=1), by the 28th day - in 0.9% (n=1) patients. During 28 days of follow up, the need for mechanical ventilation and extracorporeal membrane oxygenation was registered in 2/108 (1.8%) patients. There were no deaths directly related to COVID-19 in the assessed cohort of patients. Safety. By the 28th day of the follow up, no adverse effects due to MAB therapy were registered. CONCLUSION: An analysis of the results of a non-interventional observational study summarized in this article showed the high efficacy and safety of virus-neutralizing MAB combination (casirivimab and imdevimab) in patients with mild to moderate COVID-19 with of risk factors for severe COVID-19 in real word settings.

[The burden of COVID-19 in a heterogeneous population of immunocompromised patients - realities of the postpandemic].

On July 3, 2023, an interdisciplinary Council of Experts "The burden of COVID-19 in a heterogeneous population of immunocompromised patients - post-pandemic realities" was held in Moscow with leading experts in pulmonology, rheumatology, hematology, oncology, nephrology, allergology-immunology, transplantation, and infectious diseases. The aim of the meeting was to discuss the current clinical and epidemiologic situation related to COVID-19, the relevance of disease prevention strategies for high-risk patients. The experts addressed the following issues: 1) the disease burden of COVID-19 in 2023 for patients with immunodeficiency in different therapeutic areas; 2) the place of passive immunization with monoclonal antibodies as a method of COVID-19 prophylaxis among immunocompromised patients; 3) prerequisites for the inclusion of passive immunization of immunocompromised patients into routine clinical practice.

[HBx Protein Potentiates Hepatitis B Virus Reactivation].

Hepatitis B virus (HBV) can cause chronic hepatitis B, one of the most prevalent infectious diseases in the world. Global estimates suggest that over 2 billion people are affected by HBV, with over 250 million people developing chronic infection. Upon treatment of comorbidities, patients with chronic infection may develop an abrupt increase of viral replication-HBV reactivation-leading to liver decompensation and, in some cases, death. HBV reactivation occurs mostly due to suppression of antiviral immune response and activation of intracellular pro-viral signaling. Defining the mechanisms of HBV reactivation is necessary for the rational use of drugs and reduction of mortality rates in patients with chronic infection. In this study, for the first time we analyzed the effects of HBx protein on HBV reactivation, described reactivation of HBV from the transcriptionally inactivated state at the methylated recombinant HBV genome model, and investigated HBV reactivation upon treatment with genotoxic agents (doxorubicin and hydrogen peroxide) and targeted drug therapies (sunitinib and bortezomib). We report that both wild-type HBx protein and, to a greater extent, the mutant form of HBx protein lacking the nuclear exportation signal, potentiate viral replication and promote HBV reactivation. For the first time, we demonstrate that HBV can reactivate from the transcriptionally inactive state. Doxorubicin and hydrogen peroxide induce HBV reactivation at models of both transcriptionally active and transcriptionally silenced viral genome. Sunitinib weakly reactivates HBV, while bortezomib does not affect HBV replication in vitro.

[Antiviral Activity of CRISPR/Cas9 Ribonucleoprotein Complexes on a Hepatitis B Virus Model In Vivo].

Chronic hepatitis B (CHB) is caused by hepatitis B virus (HBV) infection. This disease is a key issue for global health. Modern methods of therapy do not completely eliminate HBV from infected cells and do not cure chronic infection. The CRISPR/Cas9 systems of site-specific nucleases can effectively cleave do not target DNA including viral genomes. The cleavage of the major form of the HBV genome, i.e., covalently closed circular DNA (cccDNA), leads to a robust reduction in viral replication and degradation or mutational inactivation of cccDNA. CRISPR/Cas9-based approaches are one of the most promising ways to achieve a 'sterilizing' cure of CHB, i.e., complete elimination of the virus from the body. Here, the HBV mouse model in vivo has been used to analyze the antiviral activity of the high-specific Cas9 protein and sgRNA targeting HBV genome. We have found that a single injection of short-lived ribonucleoprotein complexes of CRISPR/Cas9 results in a ~10-fold reduction in HBV DNA levels in the serum and liver of mice as early as 48 h after the start of the experiment. The remaining HBV DNAs have been found to harbor rare indel mutations. Developing new antivirals for treating CHB based on CRISPR/Cas9 ribonucleoprotein complexes could substantially reduce the duration of CHB therapy and, potentially, achieve complete elimination of viral infection.

[Experience of anticipatory therapy with IL-6 receptor inhibitors and perspectives for its use in the evolution of COVID-19].

The Advisory Board chaired by the chief specialist in infectious diseases of the Ministry of Health of Russian Federation, Professor V.P. Chulanov was held on June 18, 2022 in Saint Petersburg. Aim. The main purpose of the Board was following discussion: the analysis of the real-world data of levilimab as an anticipatory therapy for COVID-19 in hospitalized patients; the review of the experience and perspectives of levilimab as an anticipatory anti-inflammatory option for outpatient patients who meet defined clinical and laboratory criteria. Results. The analyzed data on clinical efficacy and safety formed the basis of recommendations proposed by experts for the use of levilimab in the inpatient and outpatient medical care for COVID-19.

Serological diagnosis and prevalence of HIV-1 infection in Russian metropolitan areas.

BACKGROUND: HIV infection is a major health problem in Russia. We aimed to assess HIV prevalence in different population groups and to compare the characteristics of 4th generation immunoassays from Abbott, Bio-Rad, Vector-Best, Diagnostic Systems, and Medical Biological Unit. METHODS: The study included 4452 individuals from the general population (GP), 391 subjects at high risk of HIV infection (HR) and 699 with potentially interfering conditions. HIV positivity was confirmed by immunoblot and by HIV RNA, seroconversion and virus diversity panels were also used. HIV avidity was employed to assess recent infections. RESULTS: The prevalence in GP was 0.40%, higher in males (0.62%) and in people aged < 40 years (0.58%). Patients attending dermo-venereal centers and drug users had a high prevalence (34.1 and 58.8%). Recent infections were diagnosed in 20% of GP and in 4.2% of HR. Assay sensitivity was 100% except for one false negative (99,54%, MBU). Specificity was 99.58-99.89% overall, but as low as 93.26% on HR (Vector-Best). Small differences on early seroconversion were recorded. Only the Abbott assay detected all samples on the viral diversity panel. CONCLUSION: HIV infection rate in the high-risk groups suggests that awareness and screening campaigns should be enhanced. Fourth generation assays are adequate but performance differences must be considered.

[Efficacy and safety of bulevirtide in patients with chronic hepatitis D and compensated cirrhosis].

AIM: To study the efficacy and safety of bulevirtide, the HBV and HDV entry inhibitor. MATERIALS AND METHODS: Analysis of the results of using bulevirtide in randomized controlled open-label comparative studies MYR202 and MYR203 in 56 patients with chronic hepatitis D and compensated cirrhosis, in monotherapy and combination with pegylated interferon alpha-2a (PEG-IFN). RESULTS: Monotherapy with bulevirtide for 24 weeks in the MYR202 study in 46 patients with compensated liver cirrhosis demonstrated: 1) a high rate of virological (100%) and biochemical response (alanine aminotransferase normalization rate 45.7%), 2) superiority of bulevirtide in efficacy over the control group (tenofovir), 3) comparability of treatment efficacy in patients with and without cirrhosis, 4) no progression of liver fibrosis with elastometry in most patients. Treatment with bulevirtide in monotherapy and combination with PEG-IFN for 48 weeks in 10 patients with compensated liver cirrhosis in the MYR203 study was accompanied by a high rate of virological response (80%) and normalization of alanine aminotransferase (70%). Bulevirtide was well tolerated, there was no deterioration in tolerability compared with patients without cirrhosis, there were no serious adverse events and cases of treatment cancellation due to adverse events. CONCLUSION: Bulevirtide is recommended as the first line of treatment for chronic hepatitis D in patients with compensated cirrhosis in monotherapy and combination with PEG-IFN.

[Pharmacoepidemiological research of COVID-19 in the Russian Federation EGIDA-2020].

AIM: An analysis of coronavirus infection in Russia and evaluation of different AVT regimens effectiveness. MATERIALS AND METHODS: The study involved a retrospective analysis of 1082 patient records with laboratory-confirmed COVID-19 in 17 regions of Russia. The number of men and women was equal, mean age 48.718.1 (median 50). Patients with moderate COVID-19 (85%) versus mild COVID-19 (15%) were characterized by higher age (median 54 vs 21 years; p0.001), higher body mass index (27.8 vs 23.4; p0.001), prevalence of chronic diseases (75.3% vs 8.5%; p0.001), including circulatory system diseases (37.8%). Moderate COVID-19 characterized higher intoxication (10.86.1 vs 4.22.7 days; p0.001) and catarrhal symptoms duration (10.25.4 vs 6.14.1 days; p0.001). RESULTS: During hospitalization 92% of the patients received AVT, 77% antibiotics, and 16% corticosteroids. Umifenovir therapy resulted in a significant reduction of intoxication (8.75.5 vs 11.75.5 days; p0.001) and catarrhal symptoms duration (8.85.1 vs 12.04.9 days; p0.001) compared to the group without AVT. The usage of INF reduced intoxication symptoms compared with the group without AVT (8.97.5 vs 11.75.5; p0.05). Therapy with hydroxychloroquine, imidazolylethanamide pentandioic acid, and lopinavir + ritonavir combination did not affect the course of COVID-19. Most of adverse reactions were related to antibiotics. CONCLUSION: Umifenovir therapy and inclusion of interferon in AVT regimens was associated improvement in the clinical manifestation of the disease among patients.

[Small Molecular Inhibitors of DNA Double Strand Break Repair Pathways Increase the ANTI-HBV Activity of CRISPR/Cas9].

The CRISPR/Cas9 nuclease system can effectively suppress the replication of the hepatitis B virus (HBV), while covalently closed circular DNA (cccDNA), a highly resistant form of the virus, persists in the nuclei of infected cells. The most common outcome of DNA double-strand breaks (DSBs) in cccDNA caused by CRISPR/Cas9 is double-strand break repair by nonhomologous end-joining, which results in insertion/deletion mutations. Modulation of the DNA double-strand break repair pathways by small molecules was shown to stimulate CRISPR/Cas9 activity and may potentially be utilized to enhance the elimination of HBV cccDNA. In this work, we used inhibitors of homologous (RI-1) and nonhomologous (NU7026) end-joining and their combination to stimulate antiviral activity of CRISPR/Cas9 on two cell models of HBV in vitro, i.e., the HepG2-1.1merHBV cells containing the HBV genome under the tet-on regulated cytomegalovirus promoter and the HepG2-1.5merHBV cells containing constitutive expression of HBV RNA under the wild-type promoter. The treatment of the cells with RI-1 or NU7026 after lentiviral transduction of CRISPR/Cas9 drops the levels of cccDNA compared to the DMSO-treated control. RI-1 and NU7026 resulted in 5.0-6.5 times more significant reduction in the HBV cccDNA level compared to the mock-control. In conclusion, the inhibition of both homologous and nonhomologous DNA double-strand break repair pathways increases the elimination of HBV cccDNA by CRISPR/Cas9 system in vitro, which may potentially be utilized as a therapeutic approach to treat chronic hepatitis B.

[Efficacy and safety of narlaprevir/ritonavir and daclatasvir non interferon combination in population of Russian patients with chronic hepatitis C].

AIM: Evaluate efficacy and safety of a combination of direct - acting antivirals narlaprevir/ritonavir with daclatasvir in patients with viral hepatitis C. MATERIALS AND METHODS: The study enrolled adult patients with HCV genotype 1b infection without demonstrated NS5A resistance - associated substitutions Y93C/H/N/S and/or L31F/M/V/I. Patients were treated with narlaprevir 200 mg QD, ritonavir 100 mg QD and daclatasvir 60 mg QD. Treatment duration was 12 weeks. Proportion of patients achieving sustained virological response 12 weeks after treatment (SVR12) was the primary efficacy endpoint. RESULTS AND DISCUSSION: In total, 105 (75.0%) patients were treatment with the study combination. Patients' age varied from 21 to 69 years, the mean age being 43.2±10.9 years. There were slightly more women (55.2%), and 69 patients (65.7%) had comorbidities. SVR 12 was 89.5% (95% CI 82.0-94.7%). In 10 of 11 patients with treatment failures NS5A resistance - associated substitutions in residues 31 and/or 93 were found, as well as less clinically relevant substitutions L28M, P58S, R30Q, Q62K. Adverse events (AEs) were found in less than one half of patients (45 patients, or 42.9% in the safety population). Almost all recorded AEs were mild to moderate. CONCLUSION: Efficacy of treatment with a combination of narlaprevir/ritonavir and daclatasvir in treatment - naïve patients with HCV genotype 1b was close to 90%. This combination was found to be safe and well - tolerated.

[Hepatitis C can be cured: will hepatitis B become next?] / Gepatit S stal izlechim. Gepatit V - sleduiushchii?

Chronic hepatitis B (CHB) and C (CHC) are one of the leading causes of cirrhosis and liver cancer with over a million of people dying annually from their consequences. In Russia CHB and CHC morbidity and related mortality show an upward trend. As a result of recent breakthroughs in antiviral therapeutics CHC became a curable disease. Modern therapeutics effectively suppress viral replication in CHB patients, but withdrawal of antivirals usually results in disease relapse. Loss of HBsAg required for the so called 'functional cure' is a very rare event. Moreover, 'complete cure' when the virus is entirely eliminated from the body is not possible due to a persistent form of covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) in hepatocytes refractory to modern antivirals. Today, there is a plethora of new promising medications being at different stages of development that target different steps of viral life cycle, including inhibitors of interaction between HBV and its entry receptor NTCP, inhibitors of HBV cccDNA, inhibitors of nucleocapsid assembly, technologies of genome editing (TALENs, CRISPR/Cas etc) and RNA-interference. In addition to direct acting antivirals, there is a number of approaches aimed at enhancement of the innate and adaptive immune responses. In experimental conditions, some of these approaches or their combinations help to achieve functional cure. However, complete elimination of the virus is possible only using technologies of genome editing, capable of specific cccDNA degradation. Nuclease systems are currently at their early stages of development, and there is a long way to prove their efficacy and safety. Nevertheless, highly promising results of the recent years leave no doubt that CRISPR/Cas systems and similar technologies can become the basis of CHB therapy.

[Overexpression of DNA-methyltransferases in persistency of cccDNA pool in chronic hepatitis B]. / Rol' giperékspressii DNK-metiltransferaz v persistentsii kol'tsevoi kovalentno zamknutoi DNK pri khronicheskom gepatite V.

AIM: To define the role of DNA-methyltransferases of type 1 and type 3A in hepatitis B viral cycle. MATERIAL AND METHODS: Human hepatoma cells HepG2 with stable expression of 1.1-mer HBV genome were transfected with vectors encoding DNA-methyltransferase 1 (DNMT1), DNA-methyltransferase 3A (DNMT3A) or were co-transfected with these vectors. Total HBV DNA copy number, relative expression of pregenomic RNA (pgRNA), S-protein-encoding RNA (S-RNA) and cccDNA were analyzed by quantitative and semi-quantitative real-time PCR-analysis with TaqMan probes for assessment of DNMTs-mediated effects on HBV. RESULTS: DNMT1 and DNMT3A suppress HBV transcription and replication, though to different magnitude. cccDNA pool is enlarged statistically significantly ≈2-fold (P<0.005) after transfection of DNMT3A, but is unaltered under DNMT1 treatment. CONCLUSION: DNMT3A regulates the size of cccDNA pool and is important for persistency of HBV infection.

[Resistance to protease inhibitors and efficiency of antiviral therapy in patients with chronic hepatitis C].

AIM: To clarify the role of virus resistance in the efficiency of antiviral therapy with protease inhibitors (PIs) chronic hepatitis C (CHC) patients, with moderate sensitivity to interferon-α. MATERIALS AND METHODS: Eight Caucasian patients (4 men and 4 women) aged 21 to 65 years (median 52.5 years) with genotype 1b hepatitis C virus (HCV) infection were included in the study. Two patients were diagnosed with liver cirrhosis; 4 had been ineffectively treated with peginterferon in combination with ribavirin. None of the patients had obesity and/or insulin resistance. All the 8 patients received triple therapy with PIs (boceprevir (n=3), telaprevir (n=4), and simeprevir (n=1)) and as a result failed to achieve a sustained virologic response. All the participants were studied to identify mutations in HCV NS3/4A region. RESULTS: Five of the 8 patients were found to have mutations in HCV NS3/4A region (substantially reducing drug susceptibility in 3 cases). CONCLUSION: In CHC patients who are moderately sensitive to interferon-α and receive therapy with PIs, resistance to the latter is critically important for the efficiency of therapy and the timely identification of resistance mutations can contribute to the choice of an optimal treatment policy.

Historical epidemiology of hepatitis C virus (HCV) in select countries - volume 2.

Chronic hepatitis C virus (HCV) infection is a leading cause of liver related morbidity and mortality. In many countries, there is a lack of comprehensive epidemiological data that are crucial in implementing disease control measures as new treatment options become available. Published literature, unpublished data and expert consensus were used to determine key parameters, including prevalence, viremia, genotype and the number of patients diagnosed and treated. In this study of 15 countries, viremic prevalence ranged from 0.13% in the Netherlands to 2.91% in Russia. The largest viremic populations were in India (8 666 000 cases) and Russia (4 162 000 cases). In most countries, males had a higher rate of infections, likely due to higher rates of injection drug use (IDU). Estimates characterizing the infected population are critical to focus screening and treatment efforts as new therapeutic options become available.

Strategies to manage hepatitis C virus (HCV) infection disease burden - volume 2.

The hepatitis C virus (HCV) epidemic was forecasted through 2030 for 15 countries, and the relative impact of two scenarios was considered: (i) increased treatment efficacy while holding the treated population constant and (ii) increased treatment efficacy and increased annual treated population. Increasing levels of diagnosis and treatment, in combination with improved treatment efficacy, were critical for achieving substantial reductions in disease burden. In most countries, the annual treated population had to increase several fold to achieve the largest reductions in HCV-related morbidity and mortality. This suggests that increased capacity for screening and treatment will be critical in many countries. Birth cohort screening is a helpful tool for maximizing resources. In most of the studied countries, the majority of patients were born between 1945 and 1985.

The present and future disease burden of hepatitis C virus (HCV) infections with today's treatment paradigm - volume 2.

Morbidity and mortality attributable to chronic hepatitis C virus (HCV) infection are increasing in many countries as the infected population ages. Models were developed for 15 countries to quantify and characterize the viremic population, as well as estimate the number of new infections and HCV related deaths from 2013 to 2030. Expert consensus was used to determine current treatment levels and outcomes in each country. In most countries, viremic prevalence has already peaked. In every country studied, prevalence begins to decline before 2030, when current treatment levels were held constant. In contrast, cases of advanced liver disease and liver related deaths will continue to increase through 2030 in most countries. The current treatment paradigm is inadequate if large reductions in HCV related morbidity and mortality are to be achieved.

[Chronic hepatitis C in Russia: current challenges and prospects].

This paper evaluates the impact of different medical care strategies for chronic hepatitis C patients in relation to its prevalence, frequency of adverse outcomes and mortality rate.

[WASTE WATERS AS THE RESERVOIR OF INTESTINAL ENTERIC VIRAL INFECTIONS].

In the paper there are presented data of field observations of the spectrum of viruses, contained in the waste waters. The studies were performed on the territory of the city and the territory unfavorable for hepatitis A. In the territory of the big city by RT-PCR in the waste liquid the enterovirus RNA was detected in 45% of samples; astroviruses--90%; noroviruses--80% and 15% of rotaviruses. Samples from 2 wells were slightly positive for the presence of HCV RNA A. In the waste liquid on the territory, unfavorable for viral hepatitis A, in 100% of the samples there were determined noro- and astroviruses RNA and adenovirus DNA, in 75%--enterovirus RNA; 50%--HAV RNA and a 25%--rotavirus RNA.