Abstract
Melatonin administration has been associated with different benefits in animals and patients suffering from liver diseases. However, there is no published data about circulating melatonin levels in patients with hepatocellular carcinoma (HCC) who underwent liver transplantation (LT). Thus, the objective of this observational and retrospective study was to determine whether patients with HCC with lower serum melatonin levels prior to LT have a higher risk of one-year mortality after LT. We measured serum levels of melatonin, malondialdehyde (to assess lipid peroxidation), and total antioxidant capacity (to assess antioxidant state) before LT. One-year surviving LT patients (n = 129) showed higher serum levels of melatonin (p = 0.001) and total antioxidant capacity (p = 0.001) and lower serum levels of malondialheyde (p = 0.01) than non-surviving LT patients (n = 16). Logistic regression analysis showed that high serum melatonin levels prior to LT were associated with lower one-year LT mortality (odds ratio = 0.525; 95% confidence interval (CI) = 0.331⁻0.834; p = 0.006). We found an association between serum levels of melatonin with serum levels of malondialheyde (rho = -0.22; p = 0.01) and total antioxidant capacity (rho = 0.21; p = 0.01). Thus, the novel findings of our study were the association between high serum melatonin levels prior to LT and survival at first year after LT and the association between serum levels of melatonin with malondialheyde and total antioxidant capacity.