Multiple Effects of Molecular Hydrogen and its Distinct Mechanism

Molecular hydrogen (H2) has been reported to be effective for a variety of disorders and its effect has been ascribed to a selective scavenge of hydroxyl radicals (•OH) at the beginning. Consumption of H2 was either by inhalation, drinking H2-containing water (H2 water), or infusion of H2-containing saline. Among various disorders, animal model of ischemic injury and Parkinson’s disease showed significant amelioration after H2 treatment. The mechanism of neuroprotection, however, is not simple. Multiple mechanisms may exist to produce acute and chronic effect. For chronic effect, H2-induced neuroprotection takes several days to develop and lasted several days, suggesting that H2 may work as a modulator of signal transduction as indicated by allergy model. The evidence that drinking H2 water was the most effective way rather than inhaling H2 in Parkinson’s disease model animal led to the finding that H2 induces ghrelin production and release from the stomach by activating β1 adrenergic receptors. The distinct mechanism due to the brain-stomach connection may help to understand the broad spectrum of H2 function. In addition, clinical trials have shown promising results.