ABSTRACT
Introduction: Disturbed redox homeostasis plays multiple roles in COVID-19 pathogenesis. Still, data on the level of oxidative stress by-products in COVID-19 patients are scarce. Aim: To assess the profile of oxidative stress by-products during the course of acute COVID-19 and get more insight into the origin of the systemic oxidative stress in these patients. Material and methods: Malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG) and advanced oxidation protein products (AOPP), as well as clinical inflammatory and biochemical parameters were determined in plasma of 58 COVID-19 patients, on admission, as well as 7 and 14 days upon admission. Results: The highest levels of MDA and AOPP were observed at the time of diagnosis. Based on correlations between 8-OHdG and ALT activity (p = 0.028) or creatinine concentration (p = 0.003) subclinical liver and kidney damage contribute to systemic oxidative stress in the early phase of disease. Seven days upon admission, a significant drop in MDA and AOPP levels was observed, while plasma concentration of 8-OHdG increased (p < 0.005). At this point, a significant correlation of AOPP with inflammatory biomarkers such as CRP (p = 0.016) and absolute number of neutrophils (p = 0.041) was found. 14 days upon admission, a noticeable increase was observed in AOPP (p = 0.004) and MDA levels (p = 0.038), compared to the second point, but without reaching initial values. Moreover, significant correlation was observed between AOPP (p = 0.046) or MDA (p = 0.029) levels with IL-6, as one of the key inflammatory players. Regarding the biochemical parameters, significant correlation of AOPP levels was found with the activity of plasma non-functional enzymes AST (p = 0.001) and LDH (p = 0.030). Conclusions: Significant changes in MDA, 8-OHdG and AOPP levels exist during the course of COVID-19. Correlation between by-products of oxidative damage and clinical immunological or biochemical parameters confirms the suggested involvement of neutrophils networks, IL-6 production, as well as liver and kidney damage involvement in systemic oxidative stress. Keywords: COVID-19;oxidative stress;MDA;AOPP;8-OHdG.