Neuroprotective and preventative effects of molecular hydrogen

: One of the beneficial effects of molecular hydrogen (H2 , hydrogen gas) is neuroprotection and prevention of neurological disorders. It is important and useful if taking H2 every day can prevent or ameliorate the progression of neurodegenerative disorders such as Parkinson’s disease or Alzheimer’s disease, both lacking specific therapeutic drugs. There are several mechanisms how H2 protects neuronal damage. Anti-oxidative, anti-inflammatory, and the regulation of endocrine system via stomach-brain connection seem to play an important role. In cellular and tissue level, H2 appears to prevent the production of reactive oxygen species (ROS), not only hydroxy radical（•OH）but also superoxide. In Parkinson’s disease model mice, chronic intake of H2 causes the release of ghrelin from the stomach. In Alzheimer’s disease model mice, sex-different neuroprotection is observed by chronic intake of H2 . In female mice, declines of estrogen and estrogen receptor- (ER) are prevented by H2 , upregulating brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine kinase receptor B (TrkB). The question how drinking H2 upregulates the release of ghrelin or attenuates the decline of estrogen remains to be investigated. The mechanism how H2 modulates endocrine systems and the fundamental question what or where is the target of H2 needs to be elucidated for better understanding of the effects of H2 .