Vol 22, No 4 (2022)

This article is dedicated to the outstanding scientist and figure of the national epidemiological doctrine, Academician of the Russian Academy of Medical Sciences Vitaly Belyakov. Through the prism of the events of recent years — the advent of pandemics of socially significant infections — a modern interpretation and confirmation of the relevance of the previously formulated theory of self-regulation of parasitic systems was given. The evolutionarily complex and diverse relationships between the microbiota and the animal world, its significant role in establishing a balance among many epidemic processes in the human population are considered and systematized. Particular attention is paid to the development of the human immunodeficiency virus and SARS-CoV-2 syndemic, as well as the latest observations of the interaction between the COVID-19 pathogen and the influenza virus. Data are presented that reflect the presence of interfering processes between the influenza virus and SARS-CoV-2, where for two years all isolated dangerous strains of SARS-CoV-2 prevented the arrival of seasonal epidemics of influenza and other acute respiratory viral infections. V. Belyakov in a certain historical format was ahead of events, describing the processes of self-regulation of the microcosm in the conditions of the macro- and microenvironment and its development, the patterns of which can be applied in the future.

BACKGROUND: Recent research results indicate that inflammatory cellular responses can play a significant role in the pathogenesis of atherosclerosis in humans and experimental animals, with a predominance in infiltrates of lymphocytes and monocytes/macrophages that contribute to destructive processes in the vascular wall. However, no comparative, differentiated morphometric analysis of the content of mononuclear cells in unstable and stable atherosclerotic lesions has been carried out so far.

AIM: Carrying out comparative histological and morphometric examination of quantitative content of lymphocytes and macrophages in normal vascular wall, in lipid stain, in unstable and in stable atherosclerotic lesions.

MATERIALS AND METHODS: The study material was samples taken during 15 autopsies aged 56 to 71 years who died from acute cardiovascular failure of atherosclerotic etiology. A comparative histological and morphometric study of the content of mononuclear cells: lymphocytes and macrophages in normal areas of the vascular wall, in lipid stains, in unstable and stable atherosclerotic lesions was carried out — a total of 50 tissue samples stained with hematoxylin and eosin.

RESULTS: A sharp increase in the content of studied cells in intima, atheromatous nucleus and adventition in unstable atherosclerotic plaques was revealed. In normal areas of the vascular wall, in initial atherosclerotic lesions and in stable plaques, the number of macrophages and lymphocytes is small.

CONCLUSIONS: In general, the results obtained are well consistent with the literature and suggest in favor of the need for lymphocytes and macrophages to form immuno-inflammatory reactions in the formation of unstable atherosclerotic lesions in humans.

BACKGROUND: In accordance with the current regulations, preclinical evaluation of the effectiveness of plasma substitutes for acute blood loss is carried out mainly on large laboratory animals (dogs, pigs) using a wide range of methods for assessing the structural and functional state of organs and systems of a biological object. It requires large expenditure of material resources and time, which is impractical at the stage of screening the effectiveness of newly developed infusion agents. In this regard, an urgent task is to develop a standardized model of acute blood loss on small laboratory animals for screening evaluation of the specific activity of infusion solutions with a subsequent research involving large laboratory animals. It is advisable to use laboratory rats as a biological object as they are the most suitable of the group of small laboratory animals for similarity of physiological laboratory indicators with humans.

AIM: To develop a model of acute blood loss using small laboratory animals for screening evaluation of specific infusion solution activity.

MATERIALS AND METHODS: Experiments were carried out on rats of the Vistar line with a weight of 330 ± 41 g. The animals were divided into 3 groups: 1 experimental (20 individuals with acute blood loss simulation without treatment), 2 experimental (20 individuals with acute blood loss simulation and its replacement with Rheopolyglucin), intact (10 individuals without modeling of blood loss). The study design included: general anesthesia (intramuscular injection Zoletil 100 and Xylazin 2% in a ratio of 1 : 5 at the rate of 0.01 ml/kg of weight), catheterization of the femoral artery followed by controlled hardware exfusion of blood at a rate of 0.5 ml/min until the establishment of persistent (for 2 minutes) arterial hypotension; hardware synchronous monitoring of mean arterial pressure (MAP) (by direct tonometry through the contralateral femoral artery); calculation of the percentage of blood loss from the estimated circulating blood volume (CBV) equal to 5% of the animal’s weight; heart rate (HR) (by electrocardiogram) during the first three hours after blood exfusion. In its capacity as a test drug Rheopolyglucin, which was administered through an arterial femoral catheter immediately after blood exfusion in volume and speed, equal to volume and speed of exfusion, was used. Additionally, for a comprehensive assessment of the mechanisms of maintaining hemodynamic parameters individual dynamic calculated indicators for each individual are proposed: the reduced shock volume of blood and the infusion efficiency indicator.

RESULTS: All rats in the experimental group died, 25% of which 17–20 minutes after blood exfusion, 75% — in range from 45 to 90 minutes. Rheopoliglyukin infusion reduced the death of animals by up to 35% and delayed the average death time to 45–55 minutes. A single exfusion of blood in rats resulted in loss of 7–9 ml of blood (46–51% of circulating blood volume), which was accompanied by a decrease in mean arterial pressure and heart rate. Compensation for the decrease in circulating blood volume, including due to infusion, was manifested by an increase in these indicators. A sign of inefficiency of compensation was a slight increase of mean arterial pressure with dynamically increasing heart rate. It is proved that an increase in the values of calculated indicators (the given stroke volume of blood and the infusion efficiency indicator) are benchmarks for effective compensation of hemodynamic disorders, including as a result of infusion of hemodynamic drugs.

CONCLUSIONS: The acute blood loss model with the calculation of the reduced shock volume of blood and the infusion efficiency index is advisable to use to assess the specific activity of infusion solutions in acute blood loss.

BACKGROUND: Endothelial dysfunction underlies the pathogenesis of many socially significant diseases. The search for new original drugs for the treatment of this condition remains an important scientific and practical task. Anti-inflammatory, anticoagulant and antioxidant effects of bivalve mollusks from the family of mussels (Mytilus edulis) hydrolysate and its derivatives have been described in different model systems.

AIM: The purpose of this study was to investigate the effect of M. edulis hydrolysate on the functional activity of EA.hy926 endothelial cell line.

MATERIALS AND METHODS: The viability and metabolic activity of endothelial cells were studied in MTT-test. To investigate the proliferative activity, a test with staining of cells with crystal violet dye was used. The ability of the preparation to neutralize the toxic effect of HOCl and H₂O₂ was evaluated using fluorescent dyes and flow cytometry.

RESULTS: It was found that the preparation did not have cytotoxicity and significantly increased the proliferation of endothelial cells in dilutions from 1:10 to 1:60. The preparation had a neutralizing effect against HOCl, and in all the studied dilutions significantly increased the viability of the endothelium. The preparation was not effective against H₂O₂, and increased H₂O₂ toxic effect in the maximal studied concentration. At the same time, the anti-inflammatory effect of M. edulis hydrolysate was not confirmed in this model system. The preparation had no effect on the IL-8 production and adhesion molecule CD54 (ICAM-1) and tissue factor CD146 the expression.

CONCLUSIONS: The preparation of M. edulis hydrolysate enhances the proliferation of endothelial cells and is able to neutralize HOCl toxic effects.

BACKGROUND: Neuroblastoma is one of the most common extracranial solid tumors in childhood. At present, epigenetic disorders play a significant role in neoplasms development. Since epigenetic changes in the cell are quite dynamic and reversible, epigenome-modulating exogenous agents can be used in epigenetic targeted therapy for various types of tumors. Therefore, the identification of these agents is still significant. Lactoferrin is one such potential molecule from the transferrin family. Currently, the anti-tumor properties of lactoferrin have been identified, but its effect on the epigenome of cells of various tumors types, particularly on neuroblastomas, is practically unknown.

AIM: To study the effect of the exogenous recombinant human apolactoferrin on the viability and epigenomic status of IMR-32 neuroblastoma cells.

MATERIALS AND METHODS: We studied human IMR-32 neuroblastoma cells after 72 hours of exposure to 8 doses of recombinant human apolactoferrin: 0.1, 0.5, 1, 5, 10, 50, 100 and 500 µg/ml. The level of genome-wide DNA methylation and the degree of chromatin compaction in IMR-32 cells were quantified using commercial kits 5-mC DNA ELISA Kit, Global DNA Methylation – LINE-1 Kit, as well as enzymatic hydrolysis of MspI / HpaII and DNaseI.

RESULTS: The recombinant apolactoferrin reduces the viability of IMR-32 and, depending on the dose, differentially affects the level of genome-wide DNA methylation (СpG dinucleotides, CCGG sites, LINE-1 repeats) and the degree of chromatin compaction. At the same time, a complex picture of the epigenomic cellular response to the effect of apo-lactoferrin was observed (nonlinear nonmonotonic dose-effect relationship).

CONCLUSIONS: We assumed that apolactoferrin modulates gene activity through epigenetic mechanisms, in particular, by changing the DNA methylation pattern and affecting the chromatin structure, which may be one of the molecular mechanisms of its anti-tumor effect.

L.A. Orbeli was one of the outstanding Russian physiologists, who at different times worked in the Department of Physiology of the Imperial Institute of Experimental Medicine under I.P. Pavlov and in St. Petersburg Marine Hospital, headed the Department of Evolutionary Physiology of the All-Union Institute of Experimental Medicine and Biostation in Koltushi (later on the Institute of Evolutionary Physiology and Pathology of Higher Nervous Activity of USSR Academy of Medical Sciences). During the Stalinist repressions he actively defended his fellow scientists, petitioning for their release. How many people were saved by L.A. Orbeli during the Stalinist terror, no one knows today. Abgar Leonovich (15.05.1939–20.12.2022), grandson of Leon Abgarovich, public figure and scientist, estimates that he saved at least a hundred people. Among those saved was the future Nobel Prize winner for physiology or medicine, Konrad Lorenz. Thanks to Leon Abragovich’s intercession, E.M. Kreps’ trial for counterrevolutionary activities ended with 5 years in a labour camp, and not the highest punishment for the scientist. Thanks to him, Kreps was able to return to his scientific activities. Such activity could not remain “unpunished” and after the “Pavlov” session Orbeli was dismissed from all posts, but in 1956 he became Director of the I.M. Sechenov Institute of Evolutionary Physiology. I.M. Sechenov Institute of Evolutionary Physiology, which he headed until his death in 1958. L.A. Orbeli was one of the first native humanist, for whom humanist activity was not less important than scientific. The article is based on report of senior researcher of FGBNU “IEM” E.T. Zakharova “Orbeli and his time”, made in Academy of Sciences (SPb, Universitetskaya Embankment, 5) 07.07.2022 at the workshop dedicated to memory of academician L.A. Orbeli, timed to 140^th anniversary since his birth.