Thiol levels in mild or moderate COVID-19 patients: A comparison of variant and classic COVID-19 cases

Systemic oxidative stress may be associated with reduced IgG antibody titers against SARS-CoV-2 in vaccinated kidney transplant recipients: A post-hoc analysis of the RECOVAC-IR observational study

BACKGROUND

Coronavirus disease 2019 (COVID-19) poses an increased risk for severe illness and suboptimal vaccination responses in patients with kidney disease, in which oxidative stress may be involved. Oxidative stress can be reliably measured by determining circulating free thiols (R-SH, sulfhydryl groups), since R-SH are rapidly oxidized by reactive species. In this study, we aimed to examine the association between serum free thiols and the ability to mount a humoral immune response to SARS-CoV-2 vaccination in kidney patients.

METHODS

Serum free thiol concentrations were measured in patients with chronic kidney disease stages 4/5 (CKD G4/5) (n = 46), on dialysis (n = 43), kidney transplant recipients (KTR) (n = 73), and controls (n = 50). Baseline serum free thiol and interferon-γ-induced protein-10 (IP-10) - a biomarker of the interferon response - were analyzed for associations with seroconversion rates and SARS-CoV-2 spike (S1)-specific IgG concentrations after two doses of the mRNA-1273 vaccine.

RESULTS

Albumin-adjusted serum free thiol concentrations were significantly lower in patients with CKD G4/5 (P < 0.001), on dialysis (P < 0.001), and KTR (P < 0.001), as compared to controls. Seroconversion rates after full vaccination were markedly reduced in KTR (52.1%) and were significantly associated with albumin-adjusted free thiols (OR = 1.76, P = 0.033). After adjustment for MMF use, hemoglobin, and eGFR, this significance was not sustained (OR = 1.49, P = 0.241).

CONCLUSIONS

KTR show suboptimal serological responses to SARS-CoV-2 vaccination, which is inversely associated with serum R-SH, reflecting systemic oxidative stress. Albeit this association was not robust to relevant confounding factors, it may at least partially be involved in the inability of KTR to generate a positive serological response after SARS-CoV-2 vaccination.

Reduced IL-8 Secretion by NOD-like and Toll-like Receptors in Blood Cells from COVID-19 Patients

Severe inflammatory responses are associated with the misbalance of innate and adaptive immunity. TLRs, NLRs, and cytokine receptors play an important role in pathogen sensing and intracellular control, which remains unclear in COVID-19. This study aimed to evaluate IL-8 production in blood cells from COVID-19 patients in a two-week follow-up evaluation. Blood samples were taken at admission (t1) and after 14 days of hospitalization (t2). The functionality of TLR2, TLR4, TLR7/8, TLR9, NOD1, and NOD2 innate receptors and IL-12 and IFN-γ cytokine receptors was evaluated by whole blood stimulation with specific synthetic receptor agonists through the quantification of IL-8, TNF-α, or IFN-γ. At admission, ligand-dependent IL-8 secretion was 6.4, 13, and 2.5 times lower for TLR2, TLR4, and endosomal TLR7/8 receptors, respectively, in patients than in healthy controls. Additionally, IL-12 receptor-induced IFN-γ secretion was lower in COVID-19 patients than in healthy subjects. We evaluated the same parameters after 14 days and observed significantly higher responses for TLR2, TLR4, TLR7/8, TLR9, and NOD1, NOD2, and IFN-γ receptors. In conclusion, the low secretion of IL-8 through stimulation with agonists of TLR2, TLR4, TLR7/8, TLR9, and NOD2 at t1 suggests their possible contribution to immunosuppression following hyperinflammation in COVID-19 disease.

Value of thiol and ischemia modified albumin (IMA) in predicting mortality in serious COVID-19 pneumonia

Background/aim

Viral infections of the respiratory tract are generally related to many factors such as excessive production of cytokines, inflammation, cellular death, redox imbalance or oxidative stress. The aim of this study was to determine the serum levels of thiol and IMA in patients with severe COVID-19 pneumonia to evaluate oxidative stress.

Study design

This was a prospective, sectional cohort study conducted at a pandemics hospital between 01.01.2022 and 01.02.2022.

Methods

A total of 153 patients who had been confirmed with severe COVID-19 pneumonia in the emergency unit were prospectively analyzed. The control group was formed by 50 healthy volunteers with similar age and no chronic disease history. Thiol and IMA levels were statistically compared both in the patient and the control groups, and within the patient groups (survived and non-survival).

Results

While 96 out of 153 patients had survived, 57 patients had non-survival. There was a statistically significant distinction between the survived and non-survival patients with regard to Thiol and IMA levels (p < 0.001). The thiol levels in the patient group were significantly lower compared to the control group, and the IMA levels were significantly higher (p < 0.001). The sensitivity, specificity and NPV were 70.2%, 86.5% and 83% when thiol cut-off value was ≤345.2 μmol/L (AUC: 0.886, p < 0.001). The sensitivity, specificity and NPV were 70.2%, 85.4% and 82.8% when the IMA cut-off was >302.9 ABSU (AUC: 0.875, p < 0.001).

Conclusions

Our results demonstrate that thiol and IMA levels may be used as bioindicators for risk classification and mortality in patients with serious COVID-19 pneumonia.

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.

COVID-19 hastalarında varyantların ve aşıların prognoza etkisi: Retrospektif gözlemsel çalışma

Aim: The effect of novel coronavirus disease 2019 (COVID-19) vaccines on variants of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is unclear. In this study, we aimed to investigate the prognostic effect of variants and vaccines in hospitalized COVID-19 patients. Materials and Methods: This retrospective study was conducted in 588 hospitalized patients with COVID-19 between May 1st, 2021 and August 31st, 2021. The patients were divided into groups according to variant analysis and demographic characteristics, laboratory data, vaccination status and in-hospital mortality rates were compared. Results: Variants (Alpha [B.1.1.7], Beta [B.1.351], Delta [B.1.617.2]) were detected in 46.3% of the patients. The intensive care unit (ICU) admission rate was 46.8% and the in-hospital mortality rate was 33.3%. There was no statistically significant difference between the patients with variant detection and those without variant detection in terms of ICU admission and in-hospital mortality. The rate of unvaccinated patients was 63.6%. The in-hospital mortality rate was similar in those vaccinated with two doses of CoronaVaC (37.1%) to that in the unvaccinated (32.9%), but higher than in those vaccinated with two doses of BNT162B2 (16.7%). Conclusion: There was no increase in the mortality rates in hospitalized patients with variants compared to those without. The mortality rate in those vaccinated with two doses of CoronaVaC was similar to that in those not vaccinated.

Effect of ArtemiC in patients with COVID-19: A Phase II prospective study

Despite intensive efforts, there is no effective remedy for COVID‐19. Moreover, vaccination efficacy declines over time and may be compromised against new SARS‐CoV‐2 lineages. Therefore, there remains an unmet need for simple, accessible, low‐cost and effective pharmacological anti‐SARS‐CoV‐2 agents. ArtemiC is a medical product comprising artemisinin, curcumin, frankincense and vitamin C, all of which possess anti‐inflammatory and anti‐oxidant properties. The present Phase II placebo‐controlled, double‐blinded, multi‐centred, prospective study evaluated the efficacy and safety of ArtemiC in patients with COVID‐19. The study included 50 hospitalized symptomatic COVID‐19 patients randomized (2:1) to receive ArtemiC or placebo oral spray, twice daily on Days 1 and 2, beside standard care. A physical examination was performed, and vital signs and blood tests were monitored daily until hospital discharge (or Day 15). A PCR assessment of SARS‐CoV‐2 carriage was performed at screening and on last visit. ArtemiC improved NEWS2 in 91% of patients and shortened durations of abnormal SpO₂ levels, oxygen supplementation and fever. No treatment‐related adverse events were reported. These findings suggest that ArtemiC curbed deterioration, possibly by limiting cytokine storm of COVID‐19, thus bearing great promise for COVID‐19 patients, particularly those with comorbidities.

Mild Coronavirus Disease 2019 (COVID-19) Is Marked by Systemic Oxidative Stress: A Pilot Study

Oxidative stress has been implicated to play a critical role in the pathophysiology of coronavirus disease 2019 (COVID-19) and may therefore be considered as a relevant therapeutic target. Serum free thiols (R-SH, sulfhydryl groups) comprise a robust marker of systemic oxidative stress, since they are readily oxidized by reactive oxygen species (ROS). In this study, serum free thiol concentrations were measured in hospitalized and non-hospitalized patients with COVID-19 and healthy controls and their associations with relevant clinical parameters were examined. Serum free thiol concentrations were measured colorimetrically (Ellman's method) in 29 non-hospitalized COVID-19 subjects and 30 age-, sex-, and body-mass index (BMI)-matched healthy controls and analyzed for associations with clinical and biochemical disease parameters. Additional free thiol measurements were performed on seven serum samples from COVID-19 subjects who required hospitalization to examine their correlation with disease severity. Non-hospitalized subjects with COVID-19 had significantly lower concentrations of serum free thiols compared to healthy controls (p = 0.014), indicating oxidative stress. Serum free thiols were positively associated with albumin (St. β = 0.710, p < 0.001) and inversely associated with CRP (St. β = -0.434, p = 0.027), and showed significant discriminative ability to differentiate subjects with COVID-19 from healthy controls (AUC = 0.69, p = 0.011), which was slightly higher than the discriminative performance of CRP concentrations regarding COVID-19 diagnosis (AUC = 0.66, p = 0.042). This study concludes that systemic oxidative stress is increased in patients with COVID-19 compared with healthy controls. This opens an avenue of treatment options since free thiols are amenable to therapeutic modulation.