الملخص الإنجليزي
COVID-19 disease, caused by the SARS-CoV-2 virus, has been linked to major inflammatory, metabolic, and oxidative stress disturbances, which may extend beyond the acute phase of the disease and contribute to cardiovascular complications. The imbalance between the different oxidant and antioxidant measures is suggested to play a major role in disease progression. Despite its known antioxidant properties, bilirubin's role in post-COVID-19 metabolic manifestations remains underexplored.
Our primary objective was to examine the relationship between serum bilirubin levels and oxidative stress markers in post-COVID-19 patients categorized by disease severity. In vitro, we evaluated the antioxidant effects of bilirubin on human serum through copper-induced oxidation assays. In vivo, we measured serum bilirubin levels and its association with key redox parameters, including reduced glutathione, glutathione peroxidase, malondialdehyde (MDA), oxidized lipoproteins, and antioxidant status as defined by the lag phase in copper-induced oxidation graphs.
The results demonstrated a significant inverse correlation between serum bilirubin levels and disease severity in post-COVID-19 patients with a p-value of 0.039. Bilirubin levels were lower in severe and mild/moderate cases, with averages of 7.08 ± 0.89 and 8.41 ± 0.6 µmol/L, respectively. In contrast, an average of 10.3 ± 0.86 µmol/L of bilirubin levels was reported for the control group. However, lower bilirubin levels were associated with higher MDA levels (R = 0.319, P = 0.003), indicating increased lipid peroxidation and oxidative stress. No significant correlations were observed between bilirubin and other redox measures such as glutathione and glutathione peroxidase. Additionally, oxidized LDL emerged as the primary predictor of MDA levels, indicating a specific link between bilirubin and LDL lipid peroxidation predicting around 7% variation in MDA levels as determined by R2 (p = 0.01).
These findings suggest that bilirubin's antioxidant properties may play a crucial role in mitigating oxidative stress and lipid peroxidation in post-COVID-19 patients. This study highlights a potential role for bilirubin as a therapeutic target for managing oxidative stress-related complications in COVID-19. Future research is encouraged to explore the therapeutic applications of bilirubin and/or its analogs in reducing disease severity and improving clinical outcomes in post-COVID-19 patients.
