High-Concentration Hydrogen Delivery During Dialysis Using an Innovative Direct Dissolution Technique: In Vivo...

Hydrogen gas (H₂) shows broad therapeutic potential. Hemodialysis, using large dialysate volumes in contact with blood, presents a promising H₂ delivery method. We developed an innovative system generating hydrogen-enriched dialysate, differing from conventional electrolysis. This system directly dissolves H₂ gas into tap water to produce saturated water, which then undergoes reverse osmosis (RO) for dialysate preparation. Using this system in a canine hemodialysis model with a single dog, we measured H₂ concentrations. High H₂ levels were consistently maintained (approximately 1,600 ppb in RO water; stable approximately 230 ppb in final dialysate). H₂ efficiently diffused into the extracorporeal blood circuit, with outlet concentrations reaching 54.0-67.7% of the dialysate level. However, low systemic arterial concentrations (pulmonary, carotid) indicated significant pulmonary clearance, suggesting H₂ primarily acts locally within the circuit and dialyzer. Compared with traditional electrolyzed water methods, this direct dissolution system delivers substantially higher and more stable H₂ concentrations. Its simpler design and potentially lower installation costs suggest feasibility for widespread clinical adoption. Future studies should explore hemodiafiltration (HDF) to potentially enhance systemic H₂ delivery and evaluate long-term clinical benefits.