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

Alternations in miR-155 and miR-200 serum levels can serve as biomarkers for COVID-19 in the post-mass vaccination era

BACKGROUND

Mass vaccination and natural immunity reduced the severity of COVID-19 cases. SARS-CoV-2 ongoing genome variations imply the use of confirmatory serologic biomarkers besides PCR for reliable diagnosis. MicroRNA molecules are intrinsic components of the innate immune system. The expression of miR155-5p and miR200c-3p was previously correlated with SARS-CoV-2 pathogenesis. This case-control study was conducted during the third peak of the COVID-19 pandemic in Egypt and aimed to calculate the accuracy of miR155-5p and miR200c-3p as biomarkers for COVID-19.

METHODS AND RESULTS

Thirty out of 400 COVID-19 patients at a main University hospital in Alexandria were included in the study along with 20 age-matched healthy controls. Plasma samples were collected for total and differential CBC. Relative quantitation of miR155-5p and miR200c-3p expression from WBCs was done by RT-qPCR. The expression of miR155-5p and miR200c-3p was positively correlated and was significantly downregulated in COVID-19 patients compared to the healthy control group (p ˂ 0.005). Both miR155-5p and miR200c-3p were of 76% and 74% accuracy as diagnostic biomarkers of COVID-19, respectively. Regarding the differentiation between mild and moderate cases, their accuracy was 80% and 70%, respectively.

CONCLUSIONS

miR155-5p and miR200c-3p expression can be used to confirm the diagnosis of COVID-19 and discriminate between mild and moderate cases, with a moderate degree of accuracy.

Catalase Activity of IgGs of Patients Infected with SARS-CoV-2

Coronavirus disease (COVID-19), caused by the SARS-CoV-2 coronavirus, leads to various manifestations of the post-COVID syndrome, including diabetes, heart and kidney disease, thrombosis, neurological and autoimmune diseases and, therefore, remains, so far, a significant public health problem. In addition, SARS-CoV-2 infection can lead to the hyperproduction of reactive oxygen species (ROS), causing adverse effects on oxygen transfer efficiency, iron homeostasis, and erythrocytes deformation, contributing to thrombus formation. In this work, the relative catalase activity of the serum IgGs of patients recovered from COVID-19, healthy volunteers vaccinated with Sputnik V, vaccinated with Sputnik V after recovering from COVID-19, and conditionally healthy donors were analyzed for the first time. Previous reports show that along with canonical antioxidant enzymes, the antibodies of mammals with superoxide dismutase, peroxidase, and catalase activities are involved in controlling reactive oxygen species levels. We here show that the IgGs from patients who recovered from COVID-19 had the highest catalase activity, and this was statistically significantly higher each compared to the healthy donors (1.9-fold), healthy volunteers vaccinated with Sputnik V (1.4-fold), and patients vaccinated after recovering from COVID-19 (2.1-fold). These data indicate that COVID-19 infection may stimulate the production of antibodies that degrade hydrogen peroxide, which is harmful at elevated concentrations.

The Impact of Serum Levels of Reactive Oxygen and Nitrogen Species on the Disease Severity of COVID-19

Elucidation of the redox pathways in severe coronavirus disease 2019 (COVID-19) might aid in the treatment and management of the disease. However, the roles of individual reactive oxygen species (ROS) and individual reactive nitrogen species (RNS) in COVID-19 severity have not been studied to date. The main objective of this research was to assess the levels of individual ROS and RNS in the sera of COVID-19 patients. The roles of individual ROS and RNS in COVID-19 severity and their usefulness as potential disease severity biomarkers were also clarified for the first time. The current case-control study enrolled 110 COVID-19-positive patients and 50 healthy controls of both genders. The serum levels of three individual RNS (nitric oxide (NO^•), nitrogen dioxide (ONO^-), and peroxynitrite (ONOO^-)) and four ROS (superoxide anion (O₂^•-), hydroxyl radical (^•OH), singlet oxygen (¹O₂), and hydrogen peroxide (H₂O₂)) were measured. All subjects underwent thorough clinical and routine laboratory evaluations. The main biochemical markers for disease severity were measured and correlated with the ROS and RNS levels, and they included tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), the neutrophil-to-lymphocyte ratio (NLR), and angiotensin-converting enzyme 2 (ACE2). The results indicated that the serum levels of individual ROS and RNS were significantly higher in COVID-19 patients than in healthy subjects. The correlations between the serum levels of ROS and RNS and the biochemical markers ranged from moderate to very strongly positive. Moreover, significantly elevated serum levels of ROS and RNS were observed in intensive care unit (ICU) patients compared with non-ICU patients. Thus, ROS and RNS concentrations in serum can be used as biomarkers to track the prognosis of COVID-19. This investigation demonstrated that oxidative and nitrative stress play a role in the etiology of COVID-19 and contribute to disease severity; thus, ROS and RNS are probable innovative targets in COVID-19 therapeutics.