# Protective effects of molecular hydrogen on lung injury from lung transplantation.
> 肺移植における分子状水素の肺傷害保護効果に関するレビュー


## Abstract

Lung transplantation exposes grafts to warm ischemia, cold ischemia, and reperfusion injury, all of which contribute to primary graft dysfunction—a leading cause of post-transplant morbidity and mortality. This review consolidates experimental evidence on the effects of molecular hydrogen (H2) on transplantation-associated lung injury. Studies in animal models demonstrated that H2, delivered via inhalation, oral hydrogen-rich water, hydrogen-rich saline injection, or hydrogen-rich water baths, improved transplant outcomes during both donor and recipient phases by reducing oxidative stress and inflammatory responses. H2 appears to modulate signal transduction and gene expression, leading to suppression of pro-inflammatory cytokines and attenuation of excess reactive oxygen species production. Its antioxidant, anti-inflammatory, and anti-apoptotic properties are well-documented, though precise mechanistic pathways remain incompletely characterized. The authors conclude that further animal studies and early-phase human trials are needed to establish a clinical foundation for H2 application in lung transplantation.

### Mechanism

H2 modulates signal transduction and gene expression to suppress pro-inflammatory cytokine secretion and reduce excess reactive oxygen species production, thereby attenuating oxidative stress and inflammation in transplanted lung tissue.

## Bibliographic

- **Authors**: Quan L, Zheng B, Zhou H
- **Journal**: Exp Biol Med (Maywood)
- **Year**: 2021
- **PMID**: [33899545](https://pubmed.ncbi.nlm.nih.gov/33899545/)
- **DOI**: [10.1177/15353702211007084](https://doi.org/10.1177/15353702211007084)
- **PMC**: [PMC8243213](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243213/)
- **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 33899545. https://h2-papers.org/en/papers/33899545
> **Source**: PubMed PMID [33899545](https://pubmed.ncbi.nlm.nih.gov/33899545/)