川崎病およびCOVID-19に対する分子状水素の化学的・生化学的作用に関するレビュー
Kawasaki disease (KD) is a systemic vasculitis representing the most prevalent acquired cardiac condition in children across numerous countries, originally identified in Japan. SARS-CoV-2 infection has caused a global pandemic since 2020, and a KD-like condition termed multisystem inflammatory syndrome in children (MIS-C) has emerged in the United States, Italy, France, England, and other European regions, with incidence estimated at roughly 6–10 times or more above historical KD rates. This review examines the chemical and biochemical properties of hydrogen gas relevant to both conditions, focusing on its capacity to reduce oxidative damage, suppress inflammatory cascades, inhibit apoptotic signaling, and attenuate abnormal vascular inflammation. The potential mechanistic basis for hydrogen gas inhalation as an investigational approach in KD and COVID-19 is discussed.
Hydrogen gas selectively scavenges reactive oxygen species, particularly hydroxyl radicals, thereby reducing oxidative stress, dampening inflammatory signaling, inhibiting apoptosis, and suppressing abnormal vascular inflammation implicated in both Kawasaki disease and COVID-19 pathophysiology.
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/33719401