This study aims to investigate effects of leutragin, an opioid peptide analogue of endogenous dynorphin 1-6, on animal survival in an experimental model of “cytokine storm” and fatal acute respiratory distress syndrome (ARDS) in C57Bl/6Y mice under different administration regimens. The aforementioned factors cause a severe course of COVID-19, which explains the current interest in seeking new treatments for ARDS. It was shown that both the prophylactic (before ARDS induction) and therapeutic (after ARDS induction) administration of leutragin in a combined mode — intramuscular injection plus inhalation leads to a statistically significant increase in the survival rate of animals. Compared to the control, leutragin significantly reduced the risk of death in animals with ARDS. The discovered prophylactic effect of leutragin deserves special attention due to its potential in preventing the onset of the disease and impeding the development of severe lung damage, thus reducing the risk of ARDS and fatal outcomes. Thus, the use of leutragin can be seen as a new effective approach to the treatment and prevention of respiratory diseases associated with a “cytokine storm” and ARDS, including the coronavirus infection COVID-19.
COVID-19 is a respiratory infection caused by the SARS-CoV-2 virus that can rapidly escalate to life-threatening pneumonia and acute respiratory distress syndrome (ARDS). Recently, extracellular high mobility group box 1 (HMGB1) has been identified as an essential component of cytokine storms that occur with COVID-19; HMGB1 levels correlate significantly with disease severity. Thus, the modulation of HMGB1 release may be vital for treating COVID-19. HMGB1 is a ubiquitous nuclear DNA-binding protein whose biological function depends on posttranslational modifications, its redox state, and its cellular localization. The acetylation of HMGB1 is a prerequisite for its translocation from the nucleus to the cytoplasm and then to the extracellular milieu. When released, HMGB1 acts as a proinflammatory cytokine that binds primarily to toll-like receptor 4 (TLR4) and RAGE, thereby stimulating immune cells, endothelial cells, and airway epithelial cells to produce cytokines, chemokines, and other inflammatory mediators. In this study, we demonstrate that inhaled [D-Ala2]-dynorphin 1-6 (leytragin), a peptide agonist of δ-opioid receptors, significantly inhibits HMGB1 secretion in mice with lipopolysaccharide- (LPS-) induced acute lung injury. The mechanism of action involves preventing HMGB1’s hyperacetylation at critical lysine residues within nuclear localization sites, as well as promoting the expression of sirtuin 1 (SIRT1), an enzyme known to deacetylate HMGB1. Leytragin’s effects are mediated by opioid receptors, since naloxone, an antagonist of opioid receptors, abrogates the leytragin effect on SIRT1 expression. Overall, our results identify leytragin as a promising therapeutic agent for the treatment of pulmonary inflammation associated with HMGB1 release. In a broader context, we demonstrate that the opioidergic system in the lungs may represent a promising target for the treatment of inflammatory lung diseases.
In order to solve the demographic problem that has arisen in Russia, comprehensive multilateral approaches are required, aimed at increasing the birth rate and reducing child and adult mortality. One approach to solve this problem is directed regulation of the human microbiome.
This research was aimed at creating novel domestic medical preparations with a modified release of active peptide substances obtained from renewable sources of biological materials. These preparations can be used for the purposes of pharmacological correction of desynchronosis by the action of biologically active substances on the processes of lipid peroxidation and antioxidant protection of cells in order to increase the body's resistance to the negative effects of various stress factors. The conducted studies have confirmed the efficacy of modified-release peptide extracts when correcting the body's oxidative status in various types of desynchronosis.
This study aims to investigate effects of leutragin — a stabilized analogue of the endogenous hexapeptide dynorphin 1-6 — in combination with pulmonary surfactant-BL on animal survival in an experimental fatal model of “cytokine storm” and acute respiratory distress syndrome (ARDS) in C57Bl/6Y mice. Compared to the control, administration of leutragin and pulmonary surfactant-BL in a combined regimen led to a statistically significant increase in the survival rate and a decrease in the risk of death in animals with ARDS. It was shown that the suppression of proinflammatory cytokine production in the lungs with a simultaneous replenishment of the endogenous surfactant with an exogenous pulmonary surfactant is a promising new pharmacological approach to the treatment of ARDS accompanied by a “cytokine storm”.
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