H₂ Papers

日本語 ・View as Markdown

The Effects of Hydrogen Gas Inhalation on Adverse Left Ventricular Remodeling After Percutaneous Coronary Intervention for ST-Elevated Myocardial Infarction　- First Pilot Study in Humans.

ST上昇型心筋梗塞に対するPCI後の左室リモデリングへの水素ガス吸入の影響：ヒトにおける初の臨床パイロット試験

human observational study inhalation mixed 1.3%

Abstract

A prospective, open-label, rater-blinded pilot study enrolled 20 STEMI patients randomized to 1.3% hydrogen gas inhalation (with 26% oxygen) or a control arm (26% oxygen alone) during primary PCI. Cardiac magnetic resonance imaging at day 7 revealed no statistically significant between-group difference in the cardiac salvage index. At 6-month follow-up, however, the hydrogen inhalation group demonstrated numerically greater improvements in LV stroke volume index (HI: +9.2 mL/m² vs. control: −1.4 mL/m²; P=0.03) and LV ejection fraction (HI: +11.0% vs. control: +1.7%; P=0.11). No serious adverse events attributable to hydrogen inhalation were recorded, supporting the feasibility and safety of this approach. The authors note that the study was underpowered for efficacy conclusions and call for a larger confirmatory trial.

Mechanism

Selective scavenging of reactive oxygen species, particularly hydroxyl radicals, by inhaled hydrogen is proposed to reduce oxidative damage during ischemia-reperfusion, thereby limiting cardiomyocyte loss and subsequent adverse left ventricular remodeling.

Bibliographic

Authors
Katsumata Y, Sano F, Abe T, Tamura T, Fujisawa T, Shiraishi Y, et al.
Journal
Circ J
Year
2017 (2017-06-23)
PMID
28321000
DOI
10.1253/circj.CJ-17-0105

Tags

Disease:ischemia-reperfusion injury (107) myocardial infarction (28) Delivery:inhalation delivery (196) Mechanism:hydroxyl radical scavenging (352) anti-inflammatory (743) oxidative stress (899) reactive oxygen species (774)

Delivery context

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

→ Evidence by delivery route

Safety notes

In air, molecular hydrogen is reported to be combustible across approximately **4% (LFL, lower flammability limit) to 75% (UFL, upper flammability limit)**. Among high-concentration hydrogen inhalers, 66% output sits inside this range, and even pure-hydrogen (100%) output forms a 4–75% concentration-gradient layer at the device–air boundary (the UFL 75% paradox). Engineering principle would therefore call for operation below LFL (the classical 4%); that figure, however, was measured under closed, pre-mixed, static conditions. For the open, dynamic inhalation environment, the empirical value reported in the literature is **10%**, which is the figure referenced in practice as the operating ceiling. The 66% / 100% output devices are recorded in the Japanese Consumer Affairs Agency accident-information database, and from these considerations are not recommended.

See also:

Other papers on the same disease / condition