The Redox Homeostasis Alteration Is Restored by Melatonin Treatment in COVID-19 Patients

Type II pneumocytes are the target of SARS-CoV-2 which alters their redox homeostasis to increase reactive oxygen species (ROS). Melatonin (MT) has antioxidant proprieties and protects mitochondrial function. Here we evaluated whether the treatment with MT compensated for the redox homeostasis alteration in serum from COVID-19 patients. We determined oxidative stress (OS) markers such as carbonyls, glutathione (GSH), total antioxidant capacity (TAC), thiols, nitrites (NO2–), lipid peroxidation (LPO), and thiols groups in serum. We also studied the enzymatic activities of glutathione peroxidase (GPx), -S-transferase (GST), reductase (GR), thioredoxin reductase (TrxR), extracellular superoxide dismutase (ecSOD) and peroxidases. There was a significant increase in LPO and carbonyls (p≤0.03) and a decrease in TAC, NO2–, thiols, GSH, (p<0.001) in COVID-19 patients. The activities of the ecSOD, TrxR, GPx, GST, GR and peroxidases were decreased (p≤ 0.04). The treatment with MT favored the activity of the antioxidant enzymes which contributed to increase TAC and restored the lost redox homeostasis. MT also modulated glucose homeostasis functioning as a glycolytic agent and inhibited the Warburg effect. Thus, MT restores the redox homeostasis which is altered in COVID-19 patients and can be used as adjuvant therapy in the SARS-CoV-2 infection.