Melatonin for neuroprotection in neonatal encephalopathy: A systematic review & meta-analysis of clinical trials

• Published in: European journal of paediatric neurology 2021-03, Vol.31, p.38-45
• Main Authors: Ahmed, Javed, Pullattayil S, Abdul Kareem, Robertson, Nicola J., More, Kiran
• Format: Article
• Language: English
• Subjects: Certainty of evidence (COE); Hypoxic-ischemic encephalopathy (HIE); Melatonin; Neonatal encephalopathy (NE); Neuroprotection; Newborn; Therapeutic hypothermia (HT)
• ISSN: 1090-3798; 1532-2130
• DOI: 10.1016/j.ejpn.2021.02.003

Melatonin has shown neuroprotective properties in pre-clinical studies of perinatal asphyxia through antioxidant, anti-apoptotic and anti-inflammatory actions. Studies have also demonstrated its safety and efficacy in neonatal encephalopathy (NE). However, its role in the current era of therapeutic hypothermia (HT) is unclear. The review aims to describe the currently available clinical evidence for Melatonin as a potential therapy for NE. Data Sources: We searched Medline, EMBASE, CINAHL, LILACS, and Cochrane central databases, published journals, and conference proceedings from inception to May 31, 2020. Study Selection: Randomized controlled trials (RCTs) of Melatonin for NE in term or late preterm infants reporting neurodevelopmental outcomes, death, or both. The evidence quality was evaluated using the GRADE system, while the recommendations were taken according to the quality. We included five RCTs involving 215 neonates. Long-term development outcome data is lacking in all except in one small study, reporting significantly higher composite cognition scores at 18 months. One study reported intermediate 6-month favorable development on follow-up. Meta-analysis of mortality in combined HT + Melatonin group vs HT alone (Studies = 2, participants = 54) demonstrated no significant reduction with relative risk (RR) 0.42; 95%CI, 0.99–1.12). The overall GRADE evidence quality was very low for a very small sample size. We did not meta-analyze the data for Melatonin alone therapy without HT, as the included studies were of very low quality. Despite strong experimental data supporting the role of Melatonin as a neuroprotective agent in NE (both alone and as an adjunct with therapeutic hypothermia), the clinical data supporting the neuroprotective effects in neonates is limited. Larger well designed, adequately powered multicentre clinical trials are urgently needed to define the neuroprotective role of Melatonin in optimizing outcomes of NE. •This systematic review found a paucity of clinical data, despite compelling advancements in preclinical research of Melatonin and neonatal neuroprotection.•The systematic review found a small trial with a higher composite cognition score at 18 months and favorable development outcome at 6 months in the combined Therapeutic hypothermia and Melatonin (HT + M) group.•Meta-analysis of mortality in combined HT + Melatonin group vs HT alone (Studies = 2, participants = 54) demonstrated no significant reduction with relative risk