Markus, Regina P.

AbstractMelatonin has been proposed as a possible treatment for the deleterious effects of hypoxia/reoxygenation (H/R), such as autophagy, inflammation, and apoptosis. Pathological pregnancies, such as preeclampsia, are associated with placental H/R, and decreased placental melatonin synthesis as well as lower melatonin levels in the placenta and maternal plasma. However, the effects of exogenous melatonin on inflammation and autophagy induced by pregnancy complications associated with H/R await investigation. This study aimed to determine as to whether melatonin protects human primary villous trophoblasts against H/R‐induced autophagy, inflammation, and apoptosis. Human primary villous cytotrophoblasts were isolated and immunopurified from normal term placentas. These cells were then exposed or not to 1 mmol/L melatonin for 72 hour in normoxia (8% O2), thereby inducing differentiation into syncytiotrophoblast that was then exposed to H/R (0.5% O2, for 4 hour) or normoxia. H/R decreased endogenous melatonin synthesis (by 68%) and interleukin (IL)‐10 levels (by 72%), coupled to increased tumor necrosis factor (TNF) (by 114%), IL‐6 (by 55%), and NFκB (by 399%), compared to normoxia. Melatonin treatment reversed the H/R effect, restoring IL‐10, TNF, and IL‐6 levels to those of the normoxia condition. Melatonin, as well as NFκB inhibition, enhanced autophagy activation, consequently increasing syncytiotrophoblast survival in H/R conditions. This study suggests that H/R, which is present in pregnancy complications, inhibits endogenous melatonin production, thereby contributing to reduced syncytiotrophoblast viability. Results indicate that exogenous melatonin treatment may afford protection against H/R‐induced damage, thereby enhancing placental cell survival, and contributing to improved fetal outcomes.

There is currently an urgent need for a viable, cheap, and readily available treatment for the Ebola virus outbreak in West Africa. Here, it is proposed that melatonin may have significant utility in helping the management of this outbreak. Optimizing natural killer (NK) cell responses seems crucial to surviving Ebola virus infection. Melatonin increases NK cell cytotoxicity significantly, suggesting efficacy in managing the Ebola virus. Under conditions of challenge, melatonin increases heme oxygenase‐1 (HO‐1), which inhibits Ebola virus replication. Melatonin also has protective effects in cases of septic shock, which, although bacterial, has similar end‐point presentations involving blood vessel leakage. Melatonin's effects on haemorrhage are mediated primarily by a decrease in pro‐inflammatory cytokines. By optimizing the appropriate immune response, melatonin is likely to afford protection to those at high risk of Ebola viral infection, as well as having direct impacts on the course of infection per se. Although no direct data pertain to the utility of melatonin in the management of the Ebola virus, convergent bodies of data suggest its utility, which is reviewed in this article. J. Med. Virol. 87:537–543, 2015. © 2015 Wiley Periodicals, Inc.