Pathophysiological aspects of antioxidant glutathione system components during covid-19 infection; a patient-based survey and clinical relevance

The glutathione system is one of the most effective antioxidant components, particularly in the respiratory system. However, little is known about the status of different components of the glutathione system in COVID-19 infection, therefore the present study aimed to investigate and discuss the status of the system-related factors during COVID-19 infection. A total of 233 serum samples were included in the study consisting of hospitalized COVID-19 patients (N=119) and healthy controls (N=114). The patients were divided into two groups: severe cases in intensive care unit (ICU-COVID, N=48), and less severe cases hospitalized in the general ward (non-ICU-COVID, N=71). Serum levels of glutathione system parameters including reduced (GSH) and oxidized (GSSG) glutathione, and the activity of two main enzymes of the system: glutathione reductase (GR) and glutathione peroxidase (GPX) were measured using commercial kits. Demographic data were obtained from the patients’ files. All steps of the study were performed based on the ethical rules of the Helsinki Declaration. The data were analyzed using SPSS software. The results showed significantly lower serum GPX levels in patients compared with controls, with significantly lower levels in severe ICU cases (p=0.04). The comparison of GSSG levels revealed a significant reduction in COVID-19 patients versus controls (p=0.0001). Rather elevated GR activity and a slightly decreasing pattern of GSH levels were observed in patients compared with controls; though the difference was not statistically significant (p=0.09 and 0.094; respectively). Glutathione system changes were observed especially with the link to disease severity. These changes can explain the contribution of the system in the pathogenesis of the disease and the body’s defense mechanisms to cope with oxidative stress induced by COVID-19 infection.