Review on oxidative stress relation on COVID-19: Biomolecular and bioanalytical approach

Oxidative stress in patients with coronavirus disease and end-stage renal disease: a pilot study

BACKGROUND

Oxidative stress, an imbalance between reactive oxygen species production and antioxidant capacity, increases in patients with coronavirus disease (COVID-19) or renal impairment. We investigated whether combined COVID-19 and end-stage renal disease (ESRD) would increase oxidative stress levels compared to each disease alone.

METHODS

Oxidative stress was compared among three groups. Two groups comprised patients with COVID-19 referred to the hospital with or without renal impairment (COVID-ESRD group [n = 18]; COVID group [n = 17]). The third group (ESRD group [n = 18]) comprised patients without COVID-19 on maintenance hemodialysis at a hospital.

RESULTS

The total oxidative stress in the COVID-ESRD group was lower than in the COVID group (p = 0.047). The total antioxidant status was higher in the COVID-ESRD group than in the ESRD (p < 0.001) and COVID (p < 0.001) groups after controlling for covariates. The oxidative stress index was lower in the COVID-ESRD group than in the ESRD (p = 0.001) and COVID (p < 0.001) groups. However, the three oxidative parameters did not differ significantly between the COVID and COVID-ESRD groups.

CONCLUSIONS

The role of reactive oxygen species in the pathophysiology of COVID-19 among patients withESRD appears to be non-critical. Therefore, the provision of supplemental antioxidants may not confer a therapeutic advantage, particularly in cases of mild COVID-19 in ESRD patients receiving hemodialysis. Nonetheless, this area merits further research.

Causal relationship between particulate matter and COVID-19 risk: A mendelian randomization study

Background

Observational studies have linked exposure to fine (PM2.5) and coarse (PM10) particulate matter air pollution with adverse COVID-19 outcomes, including higher incidence and mortality. However, some studies questioned the effect of air pollution on COVID-19 susceptibility, raising questions about the causal nature of these associations. To address this, a less biased method like Mendelian randomization (MR) is utilized, which employs genetic variants as instrumental variables to infer causal relationships in observational data.

Method

We performed two-sample MR analysis using public genome-wide association studies data. Instrumental variables correlated with PM2.5 concentration, PM2.5 absorbance, PM2.5-10 concentration and PM10 concentration were identified. The inverse variance weighted (IVW), robust adjusted profile score (RAPS) and generalized summary data-based Mendelian randomization (GSMR) methods were used for analysis.

Results

IVW MR analysis showed PM2.5 concentration [odd ratio (OR) = 3.29, 95% confidence interval (CI) 1.48-7.35, P-value = 0.0036], PM2.5 absorbance (OR = 5.62, 95%CI 1.98-15.94, P-value = 0.0012), and PM10 concentration (OR = 3.74, 95%CI 1.52-9.20, P-value = 0.0041) increased the risk of COVID-19 severity after Bonferroni correction. Further validation confirmed PM2.5 absorbance was associated with heightened COVID-19 severity (OR = 6.05, 95%CI 1.99-18.38, P-value = 0.0015 for RAPS method; OR = 4.91, 95%CI 1.65-14.59, P-value = 0.0042 for GSMR method) and hospitalization (OR = 3.15, 95%CI 1.54-6.47, P-value = 0.0018 for RAPS method). No causal links were observed between particulate matter exposure and COVID-19 susceptibility.

Conclusions

Our study established a causal relationship between smaller particle pollution, specifically PM2.5, and increased risk of COVID-19 severity and hospitalization. These findings highlight the importance of improving air quality to mitigate respiratory disease progression.

Genetic correlations, shared risk genes and immunity landscapes between COVID-19 and venous thromboembolism: evidence from GWAS and bulk transcriptome data

BACKGROUND

Patients with coronavirus disease 2019 (COVID-19) were vulnerable to venous thromboembolism (VTE), which further increases the risk of unfavorable outcomes. However, neither genetic correlations nor shared genes underlying COVID-19 and VTE are well understood.

OBJECTIVE

This study aimed to characterize genetic correlations and common pathogenic mechanisms between COVID-19 and VTE.

METHODS

We used linkage disequilibrium score (LDSC) regression and Mendelian Randomization (MR) analysis to investigate the genetic associations and causal effects between COVID-19 and VTE, respectively. Then, the COVID-19 and VTE-related datasets were obtained from the Gene Expression Omnibus (GEO) database and analyzed by bioinformatics and systems biology approaches with R software, including weighted gene co-expression network analysis (WGCNA), enrichment analysis, and single-cell transcriptome sequencing analysis. The miRNA-genes and transcription factor (TF)-genes interaction networks were conducted by NetworkAnalyst. We performed the secondary analysis of the ATAC-seq and Chip-seq datasets to address the epigenetic-regulating relationship of the shared genes.

RESULTS

This study demonstrated positive correlations between VTE and COVID-19 by LDSC and bidirectional MR analysis. A total of 26 potential shared genes were discovered from the COVID-19 dataset (GSE196822) and the VTE dataset (GSE19151), with 19 genes showing positive associations and 7 genes exhibiting negative associations with these diseases. After incorporating two additional datasets, GSE164805 (COVID-19) and GSE48000 (VTE), two hub genes TP53I3 and SLPI were identified and showed up-regulation and diagnostic capabilities in both illnesses. Furthermore, this study illustrated the landscapes of immune processes in COVID-19 and VTE, revealing the downregulation in effector memory CD8+ T cells and activated B cells. The single-cell sequencing analysis suggested that the hub genes were predominantly expressed in the monocytes of COVID-19 patients at high levels. Additionally, we identified common regulators of hub genes, including five miRNAs (miR-1-3p, miR-203a-3p, miR-210-3p, miR-603, and miR-124-3p) and one transcription factor (RELA).

CONCLUSIONS

Collectively, our results highlighted the significant correlations between COVID-19 and VTE and pinpointed TP53I3 and SLPI as hub genes that potentially link the severity of both conditions. The hub genes and their common regulators might present an opportunity for the simultaneous treatment of these two diseases.

A Review of Antibiotic Efficacy in COVID-19 Control

Severe acute respiratory disease is associated with chronic secondary infections that exacerbate symptoms and mortality. So far, many drugs have been introduced to treat this disease, none of which effectively control the coronavirus. Numerous studies have shown that mitochondria, as the center of cell biogenesis, are vulnerable to drugs, especially antibiotics. Antibiotics were widely prescribed during the early phase of the pandemic. We performed a literature review to assess the reasons, evidence, and practices on the use of antibiotics in coronavirus disease 2019 (COVID-19) in- and outpatients. The current research found widespread usage of antibiotics, mostly in an empirical context, among COVID-19 hospitalized patients. The effectiveness of this approach has not been established. Given the high death rate linked with secondary infections in COVID-19 patients and the developing antimicrobial resistance, further study is urgently needed to identify the most appropriate rationale for antibiotic therapy in these patients.

Unravelling the Mystery of COVID-19 Pathogenesis: Spike Protein and Cu Can Synergize to Trigger ROS Production

The COVID-19 pandemic has had a devastating impact on global health, highlighting the need to understand how the SARS-CoV-2 virus damages the lungs in order to develop effective treatments. Recent research has shown that patients with COVID-19 experience severe oxidative damage to various biomolecules. We propose that the overproduction of reactive oxygen species (ROS) in SARS-CoV-2 infection involves an interaction between copper ions and the virus's spike protein. We tested two peptide fragments, Ac-ELDKYFKNH-NH2 (L1) and Ac-WSHPQFEK-NH2 (L2), derived from the spike protein of the Wuhan strain and the β variant, respectively, and found that they bind Cu(II) ions and form a three-nitrogen complexes at lung pH. Our research demonstrates that these complexes trigger the overproduction of ROS, which can break both DNA strands and transform DNA into its linear form. Using A549 cells, we demonstrated that ROS overproduction occurs in the mitochondria, not in the cytoplasm. Our findings highlight the importance of the interaction between copper ions and the virus's spike protein in the development of lung damage and may aid in the development of therapeutic procedures.

Time-Resolved Fluorescence Spectroscopy of Blood, Plasma and Albumin as a Potential Diagnostic Tool for Acute Inflammation in COVID-19 Pneumonia Patients

Fluorescence lifetime measurements of blood or plasma offer valuable insights into the microenvironment and molecular interactions of fluorophores, particularly concerning albumin. Neutrophil- and hypoxia-induced oxidative stress in COVID-19 pneumonia patients leads to hyperinflammation, various oxidative modifications of blood proteins, and potential alterations in the fluorescence lifetime of tryptophan-containing proteins, especially albumin. The objective of this study was to investigate the efficacy of time-resolved fluorescence spectroscopy of blood and plasma as a prompt diagnostic tool for the early diagnosis and severity assessment of COVID-19-associated pneumonia. This study examined a cohort of sixty COVID-19 patients with respiratory symptoms. To investigate whether oxidative stress is the underlying cause of the change in fluorescence lifetime, human serum albumin was treated with chloramine T. The time-resolved spectrometer Life Spec II (Edinburgh Instruments Ltd., Livingston, UK), equipped with a sub-nanosecond pulsed 280 nm diode, was used to measure the fluorescence lifetime of blood and plasma. The findings revealed a significant reduction in the fluorescence lifetime of blood (diluted 200 times) and plasma (diluted 20 times) at 360 nm in COVID-19 pneumonia patients compared with their respective values recorded six months post-infection and those of healthy individuals. Significant negative correlations were observed between the mean fluorescence lifetime of blood and plasma at 360 nm and several severity biomarkers and advanced oxidation protein products, while a positive correlation was found with albumin and the albumin-globulin ratio. The time-resolved fluorescence spectroscopy method demonstrates the potential to be used as a preliminary screening technique for identifying patients who are at risk of developing severe complications. Furthermore, the small amount of blood required for the measurements has the potential to enable a rapid fingerstick blood test.

Bromelain: a review of its mechanisms, pharmacological effects and potential applications

The utilization of plant-derived supplements for disease prevention and treatment has long been recognized because of their remarkable potential. Ananas comosus, commonly known as pineapple, produces a group of enzymes called bromelain, which contains sulfhydryl moieties. Recent studies have shown that bromelain exhibits a wide range of activities, including anti-inflammatory, anti-diabetic, anti-cancer, and anti-rheumatic properties. These properties make bromelain a promising drug candidate for the treatment of various diseases. The anti-inflammatory activity of bromelain has been shown to be useful in treating inflammatory conditions such as osteoarthritis, rheumatoid arthritis, and asthma, whereas the anti-cancer activity of bromelain is via induction of apoptosis, inhibition of angiogenesis, and enhancement of the body's immune response. The anti-diabetic property of bromelain is owing to the improvement in glucose metabolism and reduction in insulin resistance. The therapeutic potential of bromelain has been investigated in numerous preclinical and clinical studies and a number of patents have been granted to date. Various formulations and delivery systems are being developed in order to improve the efficacy and safety of this molecule, including the microencapsulated form to treat oral inflammatory conditions and liposomal formulations to treat cancer. The development of novel drug delivery systems and formulations has further ameliorated the therapeutic potential of bromelain by improving its bioavailability and stability, while reducing the side effects. This review intends to discuss various properties and therapeutic applications of bromelain, along with its possible mechanism of action in treating various diseases. Recent patents and clinical trials concerning bromelain have also been covered.

Idiopathic pulmonary fibrosis (IPF): disease pathophysiology, targets, and potential therapeutic interventions

Idiopathic pulmonary fibrosis (IPF) is a progressive, degenerative pulmonary condition. Transforming growth factor (TGF)-β, platelet-derived growth factor (PDGF), and tumor necrosis factor-α (TNF-α) are the major modulators of IPF that mediate myofibroblast differentiation and promote fibrotic remodeling of the lung. Cigarette smoke, asbestos fiber, drugs, and radiation are known to favor fibrotic remodeling of the lungs. Oxidative stress in the endoplasmic reticulum (ER) also leads to protein misfolding and promotes ER stress, which is predominant in IPF. This phenomenon further results in excess reactive oxygen species (ROS) aggregation, increasing oxidative stress. During protein folding in the ER, thiol groups on the cysteine residue are oxidized and disulfide bonds are formed, which leads to the production of hydrogen peroxide (H2O2) as a by-product. With the accumulation of misfolded proteins in the ER, multiple signaling cascades are initiated by the cell, collectively termed as the unfolded protein response (UPR). UPR also induces ROS production within the ER and mitochondria and promotes both pro-apoptotic and pro-survival pathways. The prevalence of post-COVID-19 pulmonary fibrosis (PCPF) is 44.9%, along with an alarming increase in "Coronavirus Disease 2019" (COVID-19) comorbidities. Fibrotic airway remodeling and declined lung function are the common endpoints of SARS-CoV-2 infection and IPF. Flavonoids are available in our dietary supplements and exhibit medicinal properties. Apigenin is a flavonoid found in plants, including chamomile, thyme, parsley, garlic, guava, and broccoli, and regulates several cellular functions, such as oxidative stress, ER stress, and fibrotic responses. In this study, we focus on the IPF and COVID-19 pathogenesis and the potential role of Apigenin in addressing disease progression.

Effect of Vaccination on Platelet Mitochondrial Bioenergy Function of Patients with Post-Acute COVID-19

BACKGROUND

Mitochondrial dysfunction and redox cellular imbalance indicate crucial function in COVID-19 pathogenesis. Since 11 March 2020, a global pandemic, health crisis and economic disruption has been caused by SARS-CoV-2 virus. Vaccination is considered one of the most effective strategies for preventing viral infection. We tested the hypothesis that preventive vaccination affects the reduced bioenergetics of platelet mitochondria and the biosynthesis of endogenous coenzyme Q₁₀ (CoQ₁₀) in patients with post-acute COVID-19.

MATERIAL AND METHODS

10 vaccinated patients with post-acute COVID-19 (V + PAC19) and 10 unvaccinated patients with post-acute COVID-19 (PAC19) were included in the study. The control group (C) consisted of 16 healthy volunteers. Platelet mitochondrial bioenergy function was determined with HRR method. CoQ₁₀, γ-tocopherol, α-tocopherol and β-carotene were determined by HPLC, TBARS (thiobarbituric acid reactive substances) were determined spectrophotometrically.

RESULTS

Vaccination protected platelet mitochondrial bioenergy function but not endogenous CoQ₁₀ levels, in patients with post-acute COVID-19.

CONCLUSIONS

Vaccination against SARS-CoV-2 virus infection prevented the reduction of platelet mitochondrial respiration and energy production. The mechanism of suppression of CoQ₁₀ levels by SARS-CoV-2 virus is not fully known. Methods for the determination of CoQ₁₀ and HRR can be used for monitoring of mitochondrial bioenergetics and targeted therapy of patients with post-acute COVID-19.

The influence of ambient temperature and polyphenols from plant leaves on growth and the response to oxidative and nitrosative stress in African nightcrawler earthworm, Eudrilus eugeniae (Kinberg, 1867)

Earthworms are one of the organisms that may be affected by climate change. Finding ways to help them deal with this problem is, therefore, important and necessary. The objective of this experiment was to understand the influence of ambient temperature and polyphenols from mulberry (Morus alba L.), almond (Terminalia catappa L.) and cassava (Manihot esculenta (L.) Crantz) leaves on growth, ferric reducing antioxidant power (FRAP), malondialdehyde (MDA), hydrogen peroxide (H₂O₂) and nitric oxide (NO) concentration of the African night crawler, Eudrilus eugeniae (Kinberg, 1867) earthworm. The earthworms were cultured in 2 different conditions of ambient temperature, and in 4 types of substrate i.e. dairy cow faeces (BS), dairy cow faeces + mulberry leaves (BS + MA), almond leaves (BS + TC), and cassava leaves (BS + ME), respectively. At week 2 of the experiment, body weight, FRAP, MDA, H₂O₂ and NO were measured in the earthworms. It was found that the body weight gain (BWG) of the earthworms cultured in BS at cyclical temperature (26 + 1^oC - 34 + 1^oC - 26 + 1^oC, CyT) was higher than the constant temperature (26 ± 1 °C, CoT) (P < 0.05). FRAP of earthworms cultured in BS + TC was higher than in other groups (P < 0.05). MDA of earthworms cultured at CyT was higher than ambient temperature at CoT (P < 0.05). At CyT, the MDA of earthworms cultured in BS + MA was higher than that of those cultured in BS, BS + TC and BS + ME (P < 0.05). NO of earthworms at CoT was higher than at CyT(P < 0.05). At CoT, the NO of earthworms cultured in BS + TC was lower than that of those cultured in BS + MA and BS + ME (P < 0.05). H₂O₂ of earthworms at CoT was higher than those at CyT (P < 0.05). The level of H₂O₂ of the earthworms cultured in BS + ME at CoT was higher than at CyT (P < 0.05). In addition, the H₂O₂ of earthworms cultured in both ambient temperatures and cultured in BS + MA was higher than the other groups (P < 0.05). These phenomena indicated that low and high ambient temperatures induced nitrosative and oxidative stress in earthworms, respectively. Mulberry leaves are toxic to earthworms. On the other hand, almond leaves could reduce nitrosative stress in earthworms. While at the CoT, cassava leaves induced the production of H₂O₂ in the earthworms.

The effect of DNA repair gene variants on COVID-19 disease: susceptibility, severity, and clinical course

Oxidative stress (OS), which leads to DNA damage, plays a role in the pathogenesis of Coronavirus disease 2019 (COVID-19). We aimed to evaluate the role of DNA repair gene variants [X-ray repair cross complementing 4 (XRCC4) rs28360071, rs6869366, and X-ray cross-complementary gene 1 (XRCC1) rs25487] in susceptibility to COVID-19 in a Turkish population. We also evaluated its effect on the clinical course of the disease. A total of 300 subjects, including 200 COVID-19 patients and 100 healthy controls, were included in this study. These variants were genotyped using polymerase chain reaction (PCR) and/or PCR-restriction fragment length polymorphism (RFLP) methods. The patients were divided into three groups: those with a mild or severe infection; those who died or lived at the 28-day follow-up; those who required inpatient treatment or intensive care. There were 87 women (43.5%) and 113 men (56.5%) in the patient group. Hypertension was the most common comorbidity (26%). In the patient group, XRCC4 rs6869366 G/G genotype and G allele frequency were increased compared to controls, while XRCC4 rs6869366 G/T and T/T genotype frequencies were found to be higher in controls compared to patients. For XRCC1 rs25487, the A/A and A/G genotypes were significantly associated with COVID-19 disease. All of the patients hospitalized in the intensive care unit had the XRCC4 rs6869366 G/G genotype. In this study, we evaluated for the first time the impact of DNA repair gene variants on COVID-19 susceptibility. Results suggested that XRCC4 rs6869366 and XRCC1 rs25487 were associated with COVID-19 suspectibility and clinical course.

Role of Matrix Degradation, Oxidative Stress, Inflammation & Trace Elements in COVID-19 Patients: A Multivariate Study from India

The interrelationship between matrix degradation, oxidative stress, inflammation and trace elements can be speculated in COVID-19. The objective of the study was to evaluate the oxidative stress, inflammation and matrix degradation markers and trace elements in COVID-19 positive patients. A group of confirmed severe COVID-19 positive patients (n = 30) along with COVID-19 negative patients (n = 30) with similar symptoms were included. Both group of patients were assessed for oxidative stress markers, inflammatory cytokines, matrix metalloproteinase (MMP)s and their inhibitors along with trace elements in blood. All the data were subjected to univariate as well as multivariate analysis including PCA, PLS-DA, OPLS-DA. Diagnostic accuracy was tested by ROC curve analysis. Further relationship with Neutrophil/ lymphocyte (N/L) ratio was established if any. Increased oxidative stress, inflammation and matrix degradation is evidenced by significant rise in oxidative markers, inflammatory cytokines and MMP9/TIMP-1 ratio. Decreased Cu/Zn ratio is also observed in COVID-19 positive patients. Multivariate analysis identified SOD, Cu/Zn ratio, IL-6 and TOS, as effective discriminant among the two groups of patients. Further, accuracy was confirmed by ROC curves. Neutrophil/ lymphocyte (N/L) ratio, shows significant negative association with SOD (r= -0.75, p < 0.005) and Cu/Zn ratio (r = -0.88, p < 0.005). These data suggest the attributes of these biomarkers in disease severity. The potential use of these blood-based laboratory markers in disease prognosis seems promising and warrants further attention. Given by the symptoms and severity of the disease, it will be promising to monitor Cu/Zn ratio along with other prognostic indicators.

The Impact of Severe COVID-19 on Plasma Antioxidants

Several studies suggested the association of COVID-19 with systemic oxidative stress, in particular with lipid peroxidation and vascular stress. Therefore, this study aimed to evaluate the antioxidant signaling in the plasma of eighty-eight patients upon admission to the Clinical Hospital Dubrava in Zagreb, of which twenty-two died within a week, while the other recovered. The differences between the deceased and the survivors were found, especially in the reduction of superoxide dismutases (SOD-1 and SOD-2) activity, which was accompanied by the alteration in glutathione-dependent system and the intensification of the thioredoxin-dependent system. Reduced levels of non-enzymatic antioxidants, especially tocopherol, were also observed, which correlated with enhanced lipid peroxidation (determined by 4-hydroxynonenal (4-HNE) and neuroprostane levels) and oxidative modifications of proteins assessed as 4-HNE-protein adducts and carbonyl groups. These findings confirm the onset of systemic oxidative stress in patients with severe SARS-CoV-2, especially those who died from COVID-19, as manifested by strongly reduced tocopherol level and SOD activity associated with lipid peroxidation. Therefore, we propose that preventive and/or supplementary use of antioxidants, especially of lipophilic nature, could be beneficial for the treatment of COVID-19 patients.

Molecular Mechanisms Related to Responses to Oxidative Stress and Antioxidative Therapies in COVID-19: A Systematic Review

The coronavirus disease (COVID-19) pandemic is a leading global health and economic challenge. What defines the disease’s progression is not entirely understood, but there are strong indications that oxidative stress and the defense against reactive oxygen species are crucial players. A big influx of immune cells to the site of infection is marked by the increase in reactive oxygen and nitrogen species. Our article aims to highlight the critical role of oxidative stress in the emergence and severity of COVID-19 and, more importantly, to shed light on the underlying molecular and genetic mechanisms. We have reviewed the available literature and clinical trials to extract the relevant genetic variants within the oxidative stress pathway associated with COVID-19 and the anti-oxidative therapies currently evaluated in the clinical trials for COVID-19 treatment, in particular clinical trials on glutathione and N-acetylcysteine.

A Preliminary Study about the Role of Reactive Oxygen Species and Inflammatory Process after COVID-19 Vaccination and COVID-19 Disease

During the last couple of critical years, worldwide, there have been more than 550 million confirmed cases of COVID-19, including more than 6 million deaths (reported by the WHO); with respect to these cases, several vaccines, mainly mRNA vaccines, seem to prevent and protect from SARS-CoV-2 infection. We hypothesize that oxidative stress is one of the key factors playing an important role in both the generation and development of various kinds of disease, as well as antibody generation, as many biological paths can generate reactive oxygen species (ROS), and cellular activities can be modulated when ROS/antioxidant balance is interrupted. A pilot study was conducted in two stages during the COVID-19 pandemic in 2021 involving 222 participants between the ages of 26 and 66 years. ROS levels were measured before an after vaccination in the blood samples of 20 individuals who were vaccinated with two doses of mRNA vaccine, and an increase in ROS levels was observed after the first dose, with no modifications observed until the day before the second vaccination dose. A statistically significant difference (p < 0.001) was observed between time points 3 and 4 (before and after second dose), when participants were vaccinated for the second time, and ROS levels decreased from 21,758 to 17,580 a.u. In the second stage, blood was collected from 28 participants 45 days after COVID-19 infection (Group A), from 131 participants 45 days after receiving two doses of mRNA vaccine against COVID-19 (Group B), and from 13 healthy individuals as a control group (Group C). Additionally, antibodies levels were measured in all groups to investigate a possible correlation with ROS levels. A strong negative correlation was found between free radicals and disease antibodies in Group A (r = −0.45, p = 0.001), especially in the male subgroup (r = −0.88, p = 0.001), as well as in the female subgroup (r = −0.24, p < 0.001). Furthermore, no significant correlation (only a negative trend) was found with antibodies derived from vaccination in Group B (r = −0.01), and a negative trend was observed in the female subgroup, whereas a positive trend was observed in the male subgroup.

Efficient Electrochemical Microsensor for In Vivo Monitoring of H2O2 in PD Mouse Brain: Rational Design and Synthesis of Recognition Molecules

Hydrogen peroxide (H₂O₂), one of the most stable and abundant reactive oxygen species (ROS), acting as a modulator of dopaminergic signaling, has been intimately implicated in Parkinson's disease, creating a critical need for the selective quantification of H₂O₂ in the living brain. Current natural or nanomimic enzyme-based electrochemical methods employed for the determination of H₂O₂ suffer from inadequate selectivity and stability, due to which the in vivo measurement of H₂O₂ in the living brain remains a challenge. Herein, a series of 5-(1,2-dithiolan-3-yl)-N-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pentanamide (DBP) derivatives were designed by tuning the substitute groups and sites of a boric acid ester, which served as probes to specifically react with H₂O₂. Consequently, the reaction products, 5-(1,2-dithiolan-3-yl)-N-(4-hydroxyphen-yl)pentanamide (DHP) derivatives, converted the electrochemical signal from inactive into active. After systematically evaluating their performances, 5-(1,2-dithiolan-3-yl)-N-(3-chloro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)pentanamide (o-Cl-DBP) was finally identified as the optimized probe for H₂O₂ detection as it revealed the fastest reaction time, the largest current density, and the most negative potential. In addition, electrochemically oxidized graphene oxide (EOGO) was utilized to produce a stable inner reference. The designed electrochemical microsensor provided a ratiometric strategy for real-time tracking of H₂O₂ in a linear range of 0.5-600 μM with high selectivity and accuracy. Eventually, the efficient electrochemical microsensor was successfully applied to the measurement of H₂O₂ in Parkinson's disease (PD) mouse brain. The average levels of H₂O₂ in the cortex, striatum, and hippocampus in the normal mouse and PD mouse were systematically compared for the first time.

Potential Role of Certain Biomarkers Such as Vitamin B12, ROS, Albumin, as Early Predictors for Prognosis of COVID-19 Outcomes

COVID-19 disease is still a major global concern because of its morbidity and its mortality in severe disease. Certain biomarkers including Reactive Oxygen Species (ROS), vitamins, and trace elements are known to play a crucial role in the pathophysiology of the disease. The aim of our study was to evaluate how certain biomarkers, such as ROS, biochemical indicators, trace elements in serum blood of 139 COVID-19 hospitalized patients, and 60 non-COVID cases according to age and sex variations, can serve as the predictors for prognosis of COVID-19 outcome. An attempt of correlating these biomarkers with the severity of the disease as well as with each other is represented. All subjects were hospitalized from April 2021 until June 2021. A statistically significant increase of B12 levels (p = 0.0029) and ROS levels (p < 0.0001) as well as a decrease in albumin and Total Protein (T.P.) levels (p < 0.001) was observed especially in the early stage of the disease before CRP and ferritin elevation. Additionally, a statistically significant increase in ferritin (p = 0.007), B12 (p = 0.035, sALT p = 0.069, Glucose p = 0.012 and urea p = 0.096 and a decrease in Ca p = 0.005, T.P p = 0.052 albumin p = 0.046 between stage B (CRP values 6−30 mg/L) and C (CRP values 30−100 mg/L) was evident. Thus, this study concludes that clinicians could successfully employ biomarkers such as vitamin B12, ROS and albumin as possible prognosis tools for an early diagnosis. In addition, the total biochemical profile can assist in the understanding of the severity of COVID-19 disease, and could potentially lead to a better diet or early pharmaceutical treatment to prevent some of the more acute symptoms.

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.