Antioxidant status in children and adolescents with COVID-19

Background. The COVID-19 pandemic has raised the importance of this problem to the first stage and has affected healthcare system around the world. Despite the more favorable COVID-19 course, the child population should be at focus of special attention, due to the active participation in its distribution. The course of COVID-19 includes a cascade of pathological processes accompanied by the generation of reactive oxygen species, which can have extremely negative consequences for the developing organism. The research of these processes in children is vital and will improve the effectiveness of preventive and therapeutic measures. The aim: to analyze changes in enzymatic and non-enzymatic links in the antioxidant defense in children and adolescents with diagnosed COVID-19 infection.Materials and methods. 17 children and adolescents (average age – 12.35 ± 4.01 years) were examined, including 8 boys (47 %) and 9 girls (53 %) with COVID-19 infection. The control group of children and adolescents (practically healthy) according to the «copy-pair» principle was selected. We used spectrophotometric methods.Results. In the group of children and adolescents with diagnosed COVID-19 infection, there were lower levels of total antioxidant activity (p < 0.0001), superoxide dismutase activity (p < 0.0001), content of reduced glutathione (p = 0.048) and retinol (p = 0.015), increase in glutathione reductase activity (p = 0.015) relative to the control.Conclusion. The obtained data indicate the insufficiency of antioxidant system components number in children and adolescents with diagnosed COVID-19 infection and indicate the advisability of antioxidant therapy using to stabilize these indicators.

Ecophysiological responses of two closely related epigean and hypogean Niphargus species to hypoxia and increased temperature: Do they differ?

Ecological performance of animals depends on physiological and biochemical processes that are adjusted to the environment. The responses to hypoxia or anoxia have been frequently studied in subterranean aquatic organisms in order to find potential adaptations to restrict oxygen conditions occurring in the underground habitats. However, some previous studies have compared phylogenetic distant epigean and hypogean species or the epigean and hypogean populations of the same species due to little chance to compare closely related epigean and hypogean species. Therefore, in this study, we compared the effects of exposure to hypoxia, followed by reoxygenation, and increased temperature on oxygen consumption, potential metabolic activity, and antioxidant activities in closely related epigean and hypogean species: Niphargus zagrebensis and N. stygius. Oxygen consumption of N. stygius increased similarly during post-hypoxic recovery at 10 and 20°C (approx. 5-times), while N. zagrebensis increased its oxygen consumption for 9.7 and 4.4-times at 10 and 20°C, respectively. We observed higher exploitation of metabolic potential for current oxygen consumption during reoxygenation in N. zagrebensis than N. stygius. Exposure to hypoxia and subsequent reoxygenation at 20°C increased catalase (CAT) activity in N. stygius, but not in N. zagrebensis. We observed increased glutathione reductase activity in both Niphargus species. We concluded that respiratory and antioxidant responses to severe hypoxia and increased temperature differed between closely related epigean and hypogean Niphargus species. Hypogean Niphargus species possess physiological and biochemical characteristics that are advantageous in temperature stable subterranean environments which support inhabiting of species that have low energetic demands, while epigean Niphargus species can successfully inhabit specific surface habitats.

In Vivo Bioavailability of Selenium in Selenium-Enriched Streptococcus thermophilus and Enterococcus faecium in CD IGS Rats

The selenium (Se) enrichment of yeasts and lactic acid bacteria (LAB) has recently emerged as a novel concept; the individual health effects of these beneficial microorganisms are combined by supplying the essential micronutrient Se in a more bioavailable and less toxic form. This study investigated the bioavailability of Se in the strains Enterococcus faecium CCDM 922A (EF) and Streptococcus thermophilus CCDM 144 (ST) and their respective Se-enriched forms, SeEF and SeST, in a CD (SD-Sprague Dawley) IGS rat model. Se-enriched LAB administration resulted in higher Se concentrations in the liver and kidneys of rats, where selenocystine was the prevalent Se species. The administration of both Se-enriched strains improved the antioxidant status of the animals. The effect of the diet was more pronounced in the heart tissue, where a lower glutathione reductase content was observed, irrespective of the Se fortification in LAB. Interestingly, rats fed diets with EF and SeEF had higher glutathione reductase activity. Reduced concentrations of serum malondialdehyde were noted following Se supplementation. Diets containing Se-enriched strains showed no macroscopic effects on the liver, kidneys, heart, and brain and had no apparent influence on the basic parameters of the lipid metabolism. Both the strains tested herein showed potential for further applications as promising sources of organically bound Se and Se nanoparticles.

The effects of Bentagran on the development and antioxidant parameters of Arthrospira platensis Gomont and Chlorella vulgaris Beyerinck (Beijerinck)

The aim of the study is to determine the effects of Bentagran on growth and oxidative effects to Chlorella vulgaris and Arthrospira platensis and to evaluate the herbicide toxicity on primary producers of aquatic ecosystems. The decrease in both biomass accumulation and chlorophyll-a content in a dose-dependent manner were observed in both organisms exposed to different Bentagran concentrations (for C. vulgaris 60–960 µg mL−1; for A. platensis 100–800 µg mL−1) during 7 days. SOD activity increases significantly in Chlorella vulgaris and Arthrospira platensis at concentrations of 480 and 200 ug mL−1, respectively. Although there was no significant change in APX (ascorbate peroxidase) activity in C. vulgaris, the APX activity decreased at 400 and 600 µg mL−1 concentrations in A. platensis. While the GR (glutathione reductase) activity increased at 960 µg mL−1 concentration in C. vulgaris, it also showed increases at 100, 200 and 400 μg mL−1 concentrations, but it decreased at 600 µg mL−1 concentration in A. platensis. MDA (malondialdehyde) and proline amounts decreased only at the concentration of 960 µg mL−1, while H2O2 didn't change compared to control. Total MDA, H2O2 (hydrogen peroxide) and proline amounts did not show significant change compared to control. It is found that the effects of Bentagran on growth and antioxidant parameters are diverse at different concentrations and species, and this can be attributed to the different reactive oxygen species (ROS) production ability in these species.

Dynamics of glutathione reductase activity in rat liver tissues during cryodestruction of the right atrium

The metabolic processes of the human body are based on multiple redox reactions and oxidative stress occurs when homeostasis is imbalanced. Antioxidant system of the body is represented by such enzymes as catalase, glutathione reductase, superoxidismutase and glutathione peroxidase. Objective: to study the dynamics of glutathione reductase activity in rat liver tissues after cryodestruction of right atrial myocardium to initiate oxidative stress. Materials and methods: 420 male rats were used. The rats were divided into two groups - intact and experimental, 210 animals in each. To initiate oxidative stress, the experimental group rats underwent cryodestruction of the right atrium. The activity of glutathione reductase in the liver tissue was determined by accumulation of oxidized glutathione before the experiment, as well as on 1, 3, 5, 7 and 14 days of the experiment. Conclusions: oxidative stress arising after cryodestruction of the right atrium up to the 7th day of the experiment provokes a decrease in the glutathione reductase activity in the rat liver tissue, but the start of reparative processes helps to restore the disturbed redox equilibrium in the body and normalize the enzyme level.

The Preventive Effects of Asparagus officinalis Extract on Sodium Selenite-Induced Cataractogenesis in Experimental Animal Models

Background and Objectives. Cataract is the leading cause of blindness worldwide. Although surgery is now considered the most successful cure, the development of alternative treatments is needed due to postsurgical complications. Oxidative stress in the lens is considered to be the most crucial factor in the formation of cataracts. Therefore, the effects of the hydroalcoholic extract of Asparagus officinalis L, a traditional antioxidative plant, on cataract formation of sodium selenite were evaluated. Materials and Methods. Neonatal rats received a single dose of sodium selenite as an intraperitoneal injection (30 μmol/kg) on day 10 postnatal to induce cataract. Animals were then posttreated with various oral solutions of A. officinalis extract at 200 mg/kg or 400 mg/kg once daily on days 10–16 postnatal. Cataract was evaluated by slit-lamp, and lens opacification was analyzed in each group 24 hours after the last treatment at day seven postadministration of the extracts or vehicle. The total protein concentration of lenses, glutathione reductase activity as the glutathione antioxidant capacity, and malondialdehyde content as a marker of lipid peroxidation were further assessed in removed rat lenses on day 30 postnatal. Results. All lenses in the healthy and control plant groups were clear. Sodium selenite significantly increased cataract grade (2.8 ± 0.2) when compared to the healthy group p = 0.001 . However, cataract grades were decreased considerably as 1.9 ± 0.72 and 1.5 ± 0.85 in groups that received 200 mg/kg and 400 mg/kg oral extract of A. officinalis, respectively. A. officinalis extract also restored all abnormalities of biochemical markers induced by sodium selenite. Conclusion. Our data suggest that A. officinalis could be a promising candidate as a safe alternative treatment in cataracts upon further clinical trials. This effect is probably associated with the antioxidant activity of A. officinalis.

Effects of Long-Term Supplementation with Aluminum or Selenium on the Activities of Antioxidant Enzymes in Mouse Brain and Liver

The aim of this study was to investigate the effects of aluminum (Al) or selenium (Se) on the “primary” antioxidant defense system enzymes (superoxide dismutase, catalase, and glutathione reductase) in cells of mouse brain and liver after long-term (8-week) exposure to drinking water supplemented with AlCl3 (50 mg or 100 mg Al/L in drinking water) or Na2SeO3 (0.2 mg or 0.4 mg Se/L in drinking water). Results have shown that a high dose of Se increased the activities of superoxide dismutase and catalase in mouse brain and liver. Exposure to a low dose of Se resulted in an increase in catalase activity in mouse brain, but did not show any statistically significant changes in superoxide dismutase activity in both organs. Meanwhile, the administration of both doses of Al caused no changes in activities of these enzymes in mouse brain and liver. The greatest sensitivity to the effect of Al or Se was exhibited by glutathione reductase. Exposure to both doses of Al or Se resulted in statistically significant increase in glutathione reductase activity in both brain and liver. It was concluded that 8-week exposure to Se caused a statistically significant increase in superoxide dismutase, catalase and glutathione reductase activities in mouse brain and/or liver, however, these changes were dependent on the used dose. The exposure to both Al doses caused a statistically significant increase only in glutathione reductase activity of both organs.