H₂ Papers

日本語 ・View as Markdown

Inhalation of molecular hydrogen prevents ischemia-reperfusion liver damage during major liver resection.

大規模肝切除術における分子状水素吸入による虚血再灌流肝障害の予防

animal study inhalation positive

Abstract

This animal study examined the antioxidant, anti-inflammatory, and anti-apoptotic potential of inhaled molecular hydrogen during major liver resection in a domestic pig model. Twelve pigs were divided equally into a hydrogen inhalation group and a conventional anesthesia control group. Warm ischemia was maintained for 120 minutes, followed by 120 minutes of reperfusion. Histological assessment using the Suzuki scoring system revealed statistically significant reductions in hepatic damage in the hydrogen group. Among biochemical markers, gamma-glutamyl-transferase (GMT) showed a statistically significant difference between groups, while hepatic transaminases, alkaline phosphatase, lactate dehydrogenase, and lactate did not differ significantly. Plasma oxidative damage markers varied considerably between groups. The findings indicate that hydrogen inhalation during major hepatic surgery reduces ischemia-reperfusion-associated oxidative stress, supported by both histological and direct biochemical evidence.

Mechanism

Inhaled H2 is thought to scavenge reactive oxygen species generated during ischemia-reperfusion, thereby reducing oxidative stress, inflammatory signaling, and apoptotic cell death in hepatic tissue.

Bibliographic

Authors
Malý O, Zajak J, Hyšpler R, Turek Z, Astapenko D, Jun D, et al.
Journal
Ann Transl Med
Year
2019
PMID
32042790
DOI
10.21037/atm.2019.11.43
PMC
PMC6989999

Tags

Disease:ischemia-reperfusion injury (107) liver disease (56) Delivery:inhalation delivery (196) Mechanism:apoptosis regulation (280) 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