Antioxidants and clinical outcomes of patients with coronavirus disease 2019: A systematic review of observational and interventional studies

Role of Antioxidant Therapy in the Treatment and Prognosis of COVID-19: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Background

A significant aspect of the SARS-CoV-2 pathology involves oxidative stress, characterized by an imbalance between the production of harmful free radicals and the body's antioxidant defenses. With the ongoing evolution of SARS-CoV-2, the investigation into non-virus-specific therapeutic options, such as antioxidant therapy, has gained importance.

Objectives

This systematic review and meta-analysis aimed to summarize data from randomized control trials (RCTs) to evaluate the effectiveness and safety of antioxidant therapy in patients with SARS-CoV-2 infection.

Methods

We searched the peer-reviewed indexed literature on MEDLINE, Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, EMBASE, International Pharmaceutical Abstracts, and Scopus, from inception to July 2023.

Results

The search identified 3306 articles from which 25 were included for quantitative synthesis, with 5 studies eligible for meta-analysis. Antioxidant therapies included zinc, vitamin A, vitamin C, and combination treatments. Zinc interventions showed mixed results regarding intensive care unit admissions and hospital stays. Vitamin A studies indicated improvements in inflammatory markers. Vitamin C studies displayed inconsistent effects on clinical improvement and hospitalization. Combination treatments suggested benefits in symptom clearance and cytokine storm reduction. Meta-analysis of vitamin C studies found no significant difference in C-reactive protein concentrations (-0.50; 95% CI: -3.63, 2.63; I2 = 0%), intensive care unit stay duration (pooled mean difference: 1.44; 95% CI: 0.07, 2.81; I2 = 0%), or mortality (pooled odds ratio: 0.55; 95% CI: 0.28, 1.09; I2 = 0%), with a slight trend favoring reduced hospitalization duration (pooled mean difference: -2.37; 95% CI: -2.99, -1.76; I2 = 49%). Of the 25 studies, 8 were high quality with low bias, 6 had some concerns, and 11 were low quality with high bias.

Conclusions

The review presents mixed efficacy of antioxidant therapies for SARS-CoV-2, with some studies indicating potential benefits. Further well-designed large-scale RCTs are warranted to determine the definitive role of antioxidants in SARS-CoV-2 treatment.This systematic review was registered at PROSPERO as CRD42023430805.

The Association Between Antioxidants and COVID-19 Outcomes: a Systematic Review on Observational Studies

It is proven that the blood concentration of antioxidants can impress the severity of viral infections, including COVID-19. However, the lack of a comprehensive study accumulating existing data regarding COVID-19 can be perceived. Therefore, this systematic review is aimed to report the association between the blood concentration of several antioxidants and the overall health condition of COVID-19 patients. We summarized the available data surrounding the serum antioxidant level in COVID-19 patients and COVID-19 outcomes. A systematic search was performed in PubMed, Scopus, Web of Science, and Cochrane, and studies that evaluated the association between antioxidants and COVID-19 outcomes were included. Of 4101 articles that were viewed in the database search, 38 articles were included after the title, abstract, and full-text review. Twenty-nine studies indicated that lower serum antioxidants are associated with worse outcomes, and one study reported no association between serum zinc (Zn) level and COVID-19 outcomes. In most cases, antioxidant deficiency was associated with high inflammatory factors, high mortality, acute kidney injury, thrombosis, intensive care unit (ICU) admission, acute respiratory distress syndrome, cardiac injury, and the need for mechanical ventilation (MV), and there was no significant association between serum antioxidants level and ICU or hospital length of stay (LOS). It seems that higher levels of antioxidants in COVID-19 patients may be beneficial to prevent disease progression. However, clinical trials are needed to confirm this conclusion.

The effects of ginger supplementation on common gastrointestinal symptoms in patients with relapsing-remitting multiple sclerosis: a double-blind randomized placebo-controlled trial

BACKGROUND

Gastrointestinal (GI) symptoms affect more than 80% of individuals with relapsing-remitting multiple sclerosis (RRMS). Ginger is widely known for its GI relieving properties. Therefore, we investigated the effect of ginger supplementation on common GI symptoms in RRMS patients.

METHODS

This study was a 12-week double-blind parallel randomized controlled trial with a 3-week run-in period. The intervention (n = 26) and control (n = 26) groups received 500 mg ginger and placebo (as corn) supplements 3 times a day along with main meals, respectively. At the beginning and end of the trial, the frequency and severity of constipation, dysphagia, abdominal pain, diarrhea, bloating, belching, flatulence, heartburn, anorexia, and nausea were assessed using the visual analogue scale ranging from 0 to 100 mm. Totally, 49 participants completed the study. However, data analysis was performed on all 52 participants based on the intention-to-treat principle.

RESULTS

In comparison with placebo, ginger supplementation resulted in significant or near-significant reductions in the frequency (-23.63 ± 5.36 vs. 14.81 ± 2.78, P < 0.001) and severity (-24.15 ± 5.10 vs. 11.39 ± 3.23, P < 0.001) of constipation, the frequency (-12.41 ± 3.75 vs. 3.75 ± 1.82, P < 0.001) and severity (-13.43 ± 4.91 vs. 6.88 ± 2.69, P = 0.001) of nausea, the frequency (-9.31 ± 4.44 vs. 1.56 ± 4.05, P = 0.098) and severity (-11.57 ± 5.09 vs. 3.97 ± 3.99, P = 0.047) of bloating, and the severity of abdominal pain (-5.69 ± 3.66 vs. 3.43 ± 3.26, P = 0.069).

CONCLUSION

Ginger consumption can improve constipation, nausea, bloating, and abdominal pain in patients with RRMS.

TRIAL REGISTRATION

This trial was prospectively registered at the Iranian Registry of Clinical Trials ( www.irct.ir ) under the registration number IRCT20180818040827N3 on 06/10/2021.

Combined copper and zinc deficiency is associated with reduced SARS-CoV-2 immunization response to BNT162b2 vaccination

The essential trace elements copper, selenium and zinc are of relevance for immunity and immune response to vaccination. In this longitudinal study, adult healthcare workers (n = 126) received two doses of an mRNA vaccine (BNT162b2), and longitudinal serum samples were prepared. Vaccine-induced antibodies and their neutralizing activity were analyzed, and the trace elements copper, zinc, and selenium along with the copper transporter ceruloplasmin were measured. Subjects with combined deficiency of copper and zinc, i.e. both in the lowest tertiles at baseline, displayed particularly low antibody titers at three (Double Q1: 13 AU/mL vs. not double Q1: 29 AU/mL) and six (Double Q1: 200 AU/mL vs. not double Q1: 425 AU/mL) weeks after vaccination (p < 0.05). The results indicate the potential importance of an adequate trace element status of copper and zinc for raising a strong vaccine-induced SARS-CoV-2 antibody response, and highlights the importance of considering combined micronutrient insufficiencies, as single deficiencies may synergize.

Vascular mechanisms leading to progression of mild cognitive impairment to dementia after COVID-19: Protocol and methodology of a prospective longitudinal observational study

INTRODUCTION

Mild cognitive impairment (MCI) is a prodromal stage to dementia, affecting up to 20% of the aging population worldwide. Patients with MCI have an annual conversion rate to dementia of 15-20%. Thus, conditions that increase the conversion from MCI to dementia are of the utmost public health concern. The COVID-19 pandemic poses a significant impact on our aging population with cognitive decline as one of the leading complications following recovery from acute infection. Recent findings suggest that COVID-19 increases the conversion rate from MCI to dementia in older adults. Hence, we aim to uncover a mechanism for COVID-19 induced cognitive impairment and progression to dementia to pave the way for future therapeutic targets that may mitigate COVID-19 induced cognitive decline.

METHODOLOGY

A prospective longitudinal study is conducted at the University of Oklahoma Health Sciences Center. Patients are screened in the Department of Neurology and must have a formal diagnosis of MCI, and MRI imaging prior to study enrollment. Patients who meet the inclusion criteria are enrolled and followed-up at 18-months after their first visit. Visit one and 18-month follow-up will include an integrated and cohesive battery of vascular and cognitive measurements, including peripheral endothelial function (flow-mediated dilation, laser speckle contrast imaging), retinal and cerebrovascular hemodynamics (dynamic vessel retinal analysis, functional near-infrared spectroscopy), and fluid and crystalized intelligence (NIH-Toolbox, n-back). Multiple logistic regression will be used for primary longitudinal data analysis to determine whether COVID-19 related impairment in neurovascular coupling and increases in white matter hyperintensity burden contribute to progression to dementia.

Evaluating the role of antioxidant therapy in outcome of severe and critical COVID-19 infection requiring high flow oxygen

Objective

To determine the efficacy of antioxidant therapy in the outcome of critical COVID-19-infected patients.

Methods

At the Patel Hospital, a retrospective cohort analysis was carried out between June 2020 and October 2021. The study included a record of 200 individuals with severe or critical stage COVID-19 who were older than 18 and of either gender. Based on the antioxidant therapy, study participants were placed evenly into two groups. Antioxidant therapy was provided to one group (the exposed group), whereas the other group received simply normal COVID-19 medication (the unexposed group). Outcomes from both groups were evaluated and compared.

Results

Patients on antioxidant therapy had lesser mortality and shorter hospital stay than patients on coventional management, but the difference in proportions of mortality and length of hospital stay was statistically insignificant between groups (p > 0.05). Patients on antioxidant therapy had a significantly higher proportion of moderate to severe ARDS and septic shock than unexposed patients. A significantly higher number of patients in the unexposed group had AKI as compared to the exposed group (p = 0.048).

Conclusions

Antioxidant therapy seems to have a non-significant positive effect on mortality, hospital stay, and AKI, while it showed a negative effect on the severity of ARDS and septic shock.

The effect of ginger (Zingiber officinale) supplementation on clinical, biochemical, and anthropometric parameters in patients with multiple sclerosis: a double-blind randomized controlled trial

Introduction: different lines of evidence have shown that ginger administration may be beneficial for patients with multiple sclerosis (MS). Therefore, we aimed to investigate the effect of ginger supplementation on disability, physical and psychological quality of life (QoL), body mass index (BMI), neurofilament light chain (NfL), interlukin-17 (IL-17), matrix metalloproteinase-9 (MMP-9), and neutrophil to lymphocyte ratio (NLR) in patients with relapsing-remitting MS. Methods: this was a 12 week double-blind parallel randomized placebo-controlled trial with a 3 week run-in period. The treatment (n = 26) and control (n = 26) groups received 500 mg ginger and placebo (corn) supplements 3 times daily, respectively. Disability was evaluated using the Expanded Disability Status Scale (EDSS). QoL was rated using the Multiple Sclerosis Impact Scale (MSIS-29). BMI was calculated by dividing weight by height squared. Serum levels of NfL, IL-17, and MMP-9 were measured using the enzyme-linked immunosorbent assay. NLR was determined using a Sysmex XP-300™ automated hematology analyzer. All outcomes were assessed before and after the intervention and analyzed using the intention-to-treat principle. Results: in comparison with placebo, ginger supplementation caused a significant reduction in the EDSS (-0.54 ± 0.58 vs. 0.08 ± 0.23, P < 0.001), the MSIS-29 physical scale (-8.15 ± 15.75 vs. 4.23 ± 8.46, P = 0.001), the MSIS-29 psychological scale (-15.71 ± 19.59 vs. 6.68 ± 10.41, P < 0.001), NfL (-0.14 ± 0.97 vs. 0.38 ± 1.06 ng mL-1, P = 0.049), IL-17 (-3.34 ± 4.06 vs. 1.77 ± 6.51 ng L-1, P = 0.003), and NLR (-0.09 ± 0.53 vs. 0.53 ± 1.90, P = 0.038). Nevertheless, the differences in BMI and MMP-9 were not significant between the groups. Conclusion: ginger supplementation may be an effective adjuvant therapy for patients with relapsing-remitting MS.

The effectiveness of nano-curcumin on patients with COVID-19: A systematic review of clinical trials

The main aim of the current study was to summarize the findings of available clinical studies to assess nano-curcumin's influence on COVID patients. A comprehensive online search was performed in Scopus, PubMed, ISI Web of Science, and Google Scholar until March 2022 to identify trials that investigated the effects of nano-curcumin in patients with COVID-19. Eight studies comprising 569 patients were included in this review. Compared with placebo, nano-curcumin had no significant effect on C-reactive protein (CRP) and high-sensitivity C-reactive protein (hs-CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6). However, gene expression of IL-6 and gene expression as well as secretion of interleukin-1 beta (IL-1β) significantly decreased following nano-curcumin intervention. Nano-curcumin had beneficial effects on fever, cough, chills, myalgia, and olfactory and taste disturbances. The duration of hospitalization and mortality rate were significantly lower in the nano-curcumin group compared with the control group. Lymphocyte count was significantly increased after curcumin supplementation. Nano-curcumin also had favorable effects on O₂ saturation, sputum, chest pain, wheeze, and dyspnea in patients with COVID-19. No major adverse effects were reported in response to nano-curcumin supplementation. In summary, the results of this systematic review of clinical trials suggested that nano-curcumin supplementation has beneficial effects on inflammation, respiratory function, disease manifestations, and complications in patients with COVID-19 viral infection.

Antioxidants and clinical outcomes of patients with coronavirus disease 2019: A systematic review of observational and interventional studies

Coronavirus disease 2019 (COVID-19) is a newly emerging viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Oxidative stress appears to be a prominent contributor to the pathogenicity of SARS-CoV-2. Therefore, we carried out a systematic review of human observational and interventional studies to investigate the role of some antioxidants such as vitamins A, E, D, and C, selenium, zinc, and α-lipoic acid in the main clinical outcomes of subjects with COVID-19. Google Scholar, Cochrane Library, Web of Science, Scopus, and Medline were searched using Medical Subject Headings (MeSH) and non-MeSH terms without restrictions. Finally, 36 studies for vitamins C and D, selenium, and zinc were included in this systematic review; however, no eligible studies were found for vitamins A and E as well as α-lipoic acid. The results showed the promising role of vitamin C in inflammation, Horowitz index, and mortality; vitamin D in disease manifestations and severity, inflammatory markers, lung involvement, ventilation requirement, hospitalization, intensive care unit (ICU) admission, and mortality; selenium in cure rate and mortality; and zinc in ventilation requirement, hospitalization, ICU admission, biomarkers of inflammation and bacterial infection, and disease complications. In conclusion, it seems that antioxidants, especially vitamins C and D, selenium, and zinc, can improve multiple COVID-19 clinical outcomes. Nevertheless, more studies are necessary to affirm these results.