Pathogenesis-based preexposure prophylaxis associated with a low risk of SARS-CoV-2 infection in healthcare workers at a designated COVID-19 hospital: a pilot study

Background

At present, no agents are known to be effective at preventing COVID-19. Based on current knowledge of the pathogenesis of this disease, we suggest that SARS-CoV-2 infection might be attenuated by directly maintaining innate pulmonary redox, metabolic and dilation functions using well-tolerated medications that are known to serve these functions, specifically, a low-dose aerosolized combination of glutathione, inosine and potassium.

Methods

From June 1 to July 10, 2020, we conducted a pilot, prospective, open-label, single-arm, single-center study to evaluate the safety and efficacy of preexposure prophylaxis (PrEP) with aerosolized combination medication (ACM) on the incidence of SARS-CoV-2 positivity in 99 healthcare workers (HCWs) at a hospital designated for treating COVID-19 patients. We compared SARS-CoV-2 positivity in ACM users to retrospective data collected from 268 untreated HCWs at the same hospital. Eligible participants received an aerosolized combination of 21.3 mg/ml glutathione and 8.7 mg/ml inosine in 107 mM potassium solution for 14 days. The main outcome was the frequency of laboratory-confirmed SARS-CoV-2 cases, defined as individuals with positive genetic or immunological tests within 28 days of the study period.

Results

SARS-CoV-2 was detected in 2 ACM users (2, 95% CI: 0.3 to 7.1%), which was significantly less than the incidence in nonusers, at 24 (9, 95% CI: 5.8 to 13.0%; P = 0.02). During the PrEP period, solicited adverse events occurred in five participants; all were mild and transient reactions.

Conclusions

Our findings might be used either to prevent SARS-CoV-2 infection or to support ongoing and new research into more effective treatments for COVID-19.

Trial registration

ISRCTN, ISRCTN34160010. Registered 14 September 2020 - Retrospectively registered.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06241-1.

Bioimpedance Spectroscopy: Basics and Applications

In this review, we aim to introduce the reader to the technique of electrical impedance spectroscopy (EIS) with a focus on its biological, biomaterials, and medical applications. We explain the theoretical and experimental aspects of the EIS with the details essential for biological studies, i.e., interaction of metal electrodes with biological matter and liquids, strategies of measurement rate increasing, noise reduction in bio-EIS experiments, etc. We also give various examples of successful bio-EIS practical implementations in science and technology, from whole-body health monitoring and sensors for vision prosthetic care to single living cell examination platforms, virus disease research, biomolecules detection, and implementation of novel biomaterials. The present review can be used as a bio-EIS tutorial for students as well as a handbook for scientists and engineers because of the extensive references covering the contemporary research papers in the field.

Mathematical model of polymerase chain reaction with temperature-dependent parameters

The course of the real-time polymerase chain reaction (PCR) is determined by the temperature dependence of the kinetics of the component reactions, particularly the DNA strand hybridization. To investigate the effect of thermal processes on the reaction behavior, a mathematical model in which the variable rate constant of dissociation of "primer-single strand" complexes depends on temperature was proposed. The reaction medium temperature, which depends on time, was also introduced into the model. The proposed model of real-time PCR makes it possible to analyze different aspects of the reaction, which are important for the development of instruments and reagents for PCR.

[Current possibilities of clinical applications of breast tumors typing expression]

Whole-genome expression analysis methods significantly clarified contemporary breast cancer classification. Besides today clinical practice lacks the use of expression methods due to complexity of conduction, analysis and lack of clinical application. Further studies of breast cancer expression characteristics and clinical trials with stratification based of phonotypical features may improve the results of existing anticancer agents. Creation of limited clinically applicable test system, which incorporates all the specific breast cancer subtypes is currently needed.

[INFLUENCE OF OLEAMIDE OF WATER AND ION TRANSPORT IN THE OSMOREGULATORY ORGANS]

Application of oleamide (final concentration of 10 μM) at the skin basal surface of the frog, Rana temporaria L., augmented the short-circuit current (SCC) from 59.8 ± 2.5 to 78.2 ± 1.4 μA/cm2. Oleamide added to the serous membrane of the frog urinary bladder at a final dose of 1 μM induced more than 30-fold increase of osmotic permeability. The addition of arginine-vasotocin on the background of oleamide action further increased SCC across the isolated frog skin and osmotic permeability of the frog urinary bladder. Intraperitoneal injection of oleamide at a dose of 0.1 mM/100 g BW to water-loaded non-anesthetized Wistar rats decreased diuresis by 22%, enhanced solute-free water reabsorption and urinary sodium excretion by 31% and 55% respectively, but did not affect the renal potassium excretion. The results obtained provide evidence of similarity of oleamide and neurohypophyseal hormones effects on water and ion transport in epithelial cells of osmoregulatory organs in vertebrates.

[Magnetic nanoparticles and intracellular delivery of biopolymers]

The basic methods of intracellular delivery of biopolymers are present in this review. The structure and synthesis of magnetic nanoparticles, their stabilizing surfactants are described. The examples of the interaction of nanoparticles with biopolymers such as nucleic acids and proteins are considered. The final part of the review is devoted to problems physiology and biocompatibility of magnetic nanoparticles.

Heavy-light chain interrelations of MS-associated immunoglobulins probed by deep sequencing and rational variation

The mechanisms triggering most of autoimmune diseases are still obscure. Autoreactive B cells play a crucial role in the development of such pathologies and, in particular, production of autoantibodies of different specificities. The combination of deep-sequencing technology with functional studies of antibodies selected from highly representative immunoglobulin combinatorial libraries may provide unique information on specific features in the repertoires of autoreactive B cells. Here, we have analyzed cross-combinations of the variable regions of human immunoglobulins against the myelin basic protein (MBP) previously selected from a multiple sclerosis (MS)-related scFv phage-display library. On the other hand, we have performed deep sequencing of the sublibraries of scFvs against MBP, Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1), and myelin oligodendrocyte glycoprotein (MOG). Bioinformatics analysis of sequencing data and surface plasmon resonance (SPR) studies have shown that it is the variable fragments of antibody heavy chains that mainly determine both the affinity of antibodies to the parent autoantigen and their cross-reactivity. It is suggested that LMP1-cross-reactive anti-myelin autoantibodies contain heavy chains encoded by certain germline gene segments, which may be a hallmark of the EBV-specific B cell subpopulation involved in MS triggering.

Rate equation approach to understanding the ion-catalyzed formation of peptides

The salt-induced peptide formation is important for assessing and approaching schemes of molecular evolution. Here, we present experimental data and an exactly solvable kinetic model describing the linear polymerization of L-glutamic amino acid in water solutions with different concentrations of KCl and NaCl. The length distributions of peptides are well fitted by the model. Strikingly, we find that KCl considerably enhances the peptide yield, while NaCl does not show any catalytic effect in most cases under our experimental conditions. The greater catalytic effect of potassium ions is entirely interpreted by one and single parameter, the polymerization rate constant that depends on the concentration of a given salt in the reaction mixture. We deduce numeric estimates for the rate constant at different concentrations of the ions and show that it is always larger for KCl. This leads to an exponential increase of the potassium- to sodium-catalyzed peptide concentration ratio with length. Our results show that the ion-catalyzed peptides have a higher probability to emerge in excess potassium rather than in sodium-rich water solutions.

Potassium ions are more effective than sodium ions in salt induced peptide formation

Prebiotic peptide formation under aqueous conditions in the presence of metal ions is one of the plausible triggers of the emergence of life. The salt-induced peptide formation reaction has been suggested as being prebiotically relevant and was examined for the formation of peptides in NaCl solutions. In previous work we have argued that the first protocell could have emerged in KCl solution. Using HPLC-MS/MS analysis, we found that K⁺ is more than an order of magnitude more effective in the L-glutamic acid oligomerization with 1,1'-carbonyldiimidazole in aqueous solutions than the same concentration of Na⁺, which is consistent with the diffusion theory calculations. We anticipate that prebiotic peptides could have formed with K⁺ as the driving force, not Na⁺, as commonly believed.

Liposome-encapsulated peptides protect against experimental allergic encephalitis

Multiple sclerosis (MS) is a severe inflammatory and neurodegenerative disease with an autoimmune background. Despite the variety of therapeutics available against MS, the development of novel approaches to its treatment is of high importance in modern pharmaceutics. In this study, experimental autoimmune encephalomyelitis (EAE) in Dark Agouti rats has been treated with immunodominant peptides of the myelin basic protein (MBP) encapsulated in mannosylated small unilamellar vesicles. The results show that liposome-encapsulated MBP_46–62 is the most effective in reducing maximal disease score during the first attack, while MBP_124–139 and MBP_147–170 can completely prevent the development of the exacerbation stage. Both mannosylation of liposomes and encapsulation of peptides are critical for the therapeutic effect, since neither naked peptides nor nonmannosylated liposomes, loaded or empty, have proved effective. The liposome-mediated synergistic effect of the mixture of 3 MBP peptides significantly suppresses the progression of protracted EAE, with the median cumulative disease score being reduced from 22 to 14 points, compared to the placebo group; prevents the production of circulating autoantibodies; down-regulates the synthesis of Th1 cytokines; and induces the production of brain-derived neurotrophic factor in the central nervous system. Thus, the proposed formulation ameliorates EAE, providing for a less severe first attack and rapid recovery from exacerbation, and offers a promising therapeutic modality in MS treatment.—Belogurov, A. A., Jr., Stepanov, A. V., Smirnov, I. V., Melamed, D., Bacon, A., Mamedov, A. E., Boitsov, V. M., Sashchenko, L. P., Ponomarenko, N. A., Sharanova, S. N., Boyko, A. N., Dubina, M. V., Friboulet, A., Genkin, D. D., Gabibov, A. G. Liposome-encapsulated peptides protect against experimental allergic encephalitis.

[Clinical significance of carriage of rare variants of connexin-26 genetic polymorphism in gastric cancer]

The authors present first results of investigations of the connexin-26 gene in DNA obtained from peripheral blood of 55 patients operated on for gastric cancer. Gastric cancer patients were found to have carriage of the Cx 26 gene that was reliably associated with the invasive ability of the tumor. Change of the connexin-26 gene in gastric cancer is evidence of an important role of intercellular gap junctions in the arising and development of gastric cancer.

[The role of gap junction communication in metastatic B16 melanoma in C57BL mice]

The study is concerned with the effects of non-specific blocking gap junction communication with oleamide as well as genesis and spreading of melanoma B16 metastases to the lung in mice C57B1. The blocking exerted no distinct influence on primary tumorigenesis but had a marked effect on metastatic spread. Oleamide treatment during tumor growth led to an increase in area covered by metastases. A correlation was established between metastatic frequency and dosage: 1 mg/kg was followed by an upsurge in frequency of secondary lung tumors while 10 mg/kg--by a drop.

[The scientific and clinical value of molecular genetic changes in the intercellular gap junctions observed in colon cancer]

Colon cancer is one of the most widespread pathologies with high mortality due to recurrence and metastasis. The molecular methods of diagnosis, prognostication and biotherapy in colorectal cancer enjoyed a rapid progress during the recent decades. The hypothesis on the key role of impaired intercellular gap junctions in the onset and progression of malignant tumors is a promising trend in carcinogenesis research. We have recently discovered a variety of tumor-specific mutations of connexin 43 gene in advanced colorectal cancer (Oncogene. -2002.-Vol.21, No.32-pp.4992-4996), which confirms the above hypothesis in malignant tumor progression. We believe that further studies of connexins' mutation changes in tumor growth is a promising trend in research of its etiology and pathogenesis and in designing new methods of diagnostics and treatment of colonic and other gastrointestinal cancers.

[Circadian features of carcinogenesis of the large intestine induced by 1,2-dimethylhydrazine in rats]

The study was concerned with comparison of carcinogenesis induced in the rat large intestine by 5 single doses of 1,2-dimethylhydrazine (DMH) 21 mg/kg injected at different circadian stages--either at 10 a.m. or 10 p.m. Evening injections were followed by significant decrease in incidence (from 91 to 75%) and size of tumor (27.2-15.5 mm2). Also, there were relatively fewer large tumors in the evening series.

Connexin 43, but not connexin 32, is mutated at advanced stages of human sporadic colon cancer

The membrane-spanning connexin proteins form microscopic intercellular channels that directly connect the cytoplasms of adjacent cells and as such have been implicated in maintenance of tissue homeostasis. They are considered to act as tumor suppressors since their function or expression is frequently aberrant in tumor cells. Several mechanisms appear to be involved in this, but irreversible mutational alterations have not yet been proved to be among them. In this study we have demonstrated for the first time that connexin 43 but not connexin 32 is specifically and quite frequently mutated in human colon sporadic adenocarcinomas. All tumor-associated mutations led to a shift of reading frame and were located in the multifunctional carboxyl-terminal domain of the protein. Expression of mutated connexin 43 protein was restricted to invasive structures of tumors. These findings suggest that mutational alterations of connexin 43 are involved in advanced stages of progression of human colon cancer towards malignancy.

[The effect of dexamethasone on the functional features in rats with Pliss lymphosarcoma transplant]

A computer-assisted method of video imaging the adhesive, permeability and thrombogenic properties of microvessels was used to study the effect of dexamethasone on the functional activity of the mesenteric microvascular endothelium in rats with Pliss' lymphosarcoma. Dexamethasone-21 Na-phosphate (0.1 mg/ml) was supplied to the desired mesenteric area and the necessary measurements were carried out. The latter showed that tumor growth was associated with microcirculation disturbances, namely, raised leukocyte adhesion to the mesenteric microvascular endothelium, microvascular permeability and thrombogenicity. Enhanced microvascular sensitivity to dexamethasone pointed to the important role played by changes in the adhesive properties of the endothelium among general paraneoplastic disorders of microcirculation.

Microvascular endothelium dysfunction during growth of transplanted lymphosarcoma and glioma in rats

The changes of endothelium functional parameters (adhesivity, permeability, thrombogenity and thromboresistance) in mesenteric microvasculature in rats with two transplanted tumors: fast-growing Pliss' lymphosarcoma (PLS) and slow-growing glioma-35 (G-35) were studied, using a complex method, based upon a computer-assisted microscopic video image processing. The endothelial dysfunction in mesenteric microvessels is characterized by the increase of leukocyte adhesion to the endothelial cells, microvessels permeability and their thromboresistance properties decrease in tumor-bearing rats. The observed changes are shown to be the nonspecific manifestation of the tumor process development. They are determined by the duration of the process development and are not dependent on the tumor node size.

Microvascular endothelium dysfunction in rats bearing 1,2-dimethylhydrazine-induced colon tumors

Functional parameters (adhesivity, permeability, thrombogenicity and thromboresistance) of the mesenteric microvasculature endothelium in rats bearing 1,2-dimethylhydrazine (DMH) induced colon tumors were studied using a complex method, based upon computer-assisted microscopic video image processing. It was shown that paraneoplastic endothelial dysfunction in rat mesenteric microvessels is characterized by an increase in leukocyte adhesion to the endothelium, microvessel permeability and thrombogenic properties. It was demonstrated that the observed changes are the consequences of tumor growth and are related to tumor size and the duration of the process.

[The microvascular permeability of the skin and mesentery in rats adapting to hypoxia]

Changes of the rat skin and mesenteric microvascular permeability for Na-fluorescine were studied during adaptation to intermittent hypobaric hypoxia. The data obtained revealed that the microvascular permeability increased on the 10 th day after the hypoxia and decreased within 25 days of hte adaptation to the hypoxia in both areas under study.