分子状水素の臨床応用における最新動向：吸入療法を中心としたナラティブレビュー
Molecular hydrogen (H2) has attracted growing interest as a biomedical agent with potential relevance to neurological, cardiovascular, oncological, and respiratory conditions. Preclinical evidence points to selective antioxidant, anti-inflammatory, and cytoprotective mechanisms as the basis for observed benefits. Available clinical data are generally encouraging; however, the field is constrained by small study populations, heterogeneous methodologies, and the lack of standardized delivery systems. This narrative review consolidates existing clinical experience with inhaled H2, examines the principal limitations of the current literature, and outlines priority areas for future investigation, including the validation of delivery platforms that would facilitate broader and more rigorous clinical research.
H2 is proposed to exert its effects through selective scavenging of highly reactive species such as hydroxyl radicals and peroxynitrite, alongside anti-inflammatory and cytoprotective actions that collectively reduce cellular damage.
For inhalation applications of molecular hydrogen, the lower flammability limit (LFL) deserves careful handling. The classical 4% figure applies to closed-system mixtures; the practical inhalation-environment threshold is 10%. Even pure-hydrogen output (the UFL 75% paradox) passes through the flammable range at the air–gas boundary. High-concentration (66% / 100%) inhalers are documented in the Japanese Consumer Affairs Agency accident-information database and are not recommended.
See also:
https://h2-papers.org/en/papers/41449652