# Molecular hydrogen as an emerging therapeutic medical gas for neurodegenerative and other diseases.
> 神経変性疾患をはじめとする多様な疾患における分子状水素の医療ガスとしての可能性


## Abstract

Over a four-and-a-half-year period, molecular hydrogen has been evaluated across 63 disease models and human conditions. The majority of investigations used rodent models, encompassing two Parkinson's disease paradigms and three Alzheimer's disease paradigms. Particularly notable outcomes were recorded in oxidative stress-driven conditions such as neonatal cerebral hypoxia, ischemia-reperfusion affecting the spinal cord, heart, lung, liver, kidney, and intestine, as well as organ transplantation scenarios. Six human conditions have been examined: type 2 diabetes mellitus, metabolic syndrome, hemodialysis, inflammatory and mitochondrial myopathies, brainstem infarction, and radiation-induced adverse events. Two unresolved questions persist: the absence of a clear dose-response relationship despite marked effects from small hydrogen quantities, and the paradox of significant outcomes from supplemental hydrogen despite large endogenous production by intestinal bacteria. Clarifying the molecular mechanisms and identifying optimal administration parameters for each condition remain important research priorities.

### Mechanism

Molecular hydrogen is thought to selectively neutralize reactive oxygen species, particularly hydroxyl radicals, thereby reducing oxidative stress-mediated cellular damage. However, the absence of a dose-response relationship and the role of endogenous intestinal hydrogen production remain mechanistically unexplained.

## Bibliographic

- **Authors**: Ohno K, Ichihara M, Ito M
- **Journal**: Oxid Med Cell Longev
- **Year**: 2012
- **PMID**: [22720117](https://pubmed.ncbi.nlm.nih.gov/22720117/)
- **DOI**: [10.1155/2012/353152](https://doi.org/10.1155/2012/353152)
- **PMC**: [PMC3377272](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3377272/)
- **Study type**: review
- **Delivery route**: mixed routes
- **Effect reported**: not assessed

## Delivery context

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

## Safety notes

This study combines multiple delivery routes. As a general principle, the most efficient route for routine hydrogen intake is inhalation. Inhalation carries explosion risk (empirical LFL of 10%; high-concentration devices are documented in the Consumer Affairs Agency accident database and are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 22720117. https://h2-papers.org/en/papers/22720117
> **Source**: PubMed PMID [22720117](https://pubmed.ncbi.nlm.nih.gov/22720117/)