Inhalation of hydrogen gas elevates urinary 8-hydroxy-2'-deoxyguanine in Parkinson's disease.
パーキンソン病患者における水素ガス吸入と尿中8-OHdG上昇：ランダム化二重盲検クロスオーバー試験
Abstract
A randomized, double-blind, placebo-controlled crossover trial with an 8-week washout period enrolled 20 Parkinson's disease (PD) patients who inhaled approximately 1.2–1.4% hydrogen gas for 10 minutes twice daily over 4 weeks. Olfactory function, non-motor symptoms, activities of daily living, and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) were assessed. No statistically significant changes in clinical PD parameters were detected; however, urinary 8-OHdG concentrations rose by approximately 16%. This magnitude of increase is substantially smaller than the over 300% elevation seen in diabetes and is more comparable to levels observed following intense physical exercise. The authors propose that hydrogen-induced oxidative stress markers may reflect hormetic cellular adaptation, potentially involving Nrf2 and NF-κB pathway activation and heat shock responses, suggesting that beneficial effects of hydrogen could be mediated partly through such mechanisms.
Mechanism
Hydrogen inhalation may activate the Nrf2 and NF-κB signaling pathways along with heat shock responses, inducing cytoprotective cellular adaptations through a hormetic mechanism, as reflected by a modest elevation in urinary 8-OHdG.
Bibliographic
- Authors
- Hirayama M, Ito M, Minato T, Yoritaka A, LeBaron TW, Ohno K
- Journal
- Med Gas Res
- Year
- 2018
- PMID
- 30713666
- DOI
- 10.4103/2045-9912.248264
- PMC
- PMC6352570
Tags
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.
Safety notes
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