Therapeutic efficacy of infused molecular hydrogen in saline on rheumatoid arthritis: a randomized, double-blind, placebo-controlled pilot study

Antioxidant Therapies as Emerging Adjuncts in Rheumatoid Arthritis: Targeting Oxidative Stress to Enhance Treatment Outcomes

Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by persistent inflammation and progressive joint destruction. Recent data underscore oxidative stress as a primary factor in the pathophysiology of rheumatoid arthritis, intensifying inflammatory processes and tissue damage via the overproduction of reactive oxygen species (ROS) and compromised antioxidant defenses. Current therapies, including disease-modifying antirheumatic drugs (DMARDs), primarily target immune dysregulation but fail to address oxidative stress, necessitating novel adjunctive treatment strategies. This review explores the potential of antioxidant-based therapies as complementary approaches to RA management. Natural compounds such as curcumin, resveratrol, sulforaphane, and propolis exhibit strong anti-inflammatory and antioxidative properties by modulating redox-sensitive pathways, including nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and nuclear factor erythroid 2-related factor 2(Nrf2)/heme oxygenase (HO-1). N-acetylcysteine (NAC) replenishes intracellular glutathione, enhancing cellular resilience against oxidative stress. Additionally, molecular hydrogen (H2) selectively neutralizes harmful ROS, reducing oxidative damage and inflammation. The role of vitamin supplementation (D, B12, C, and K) in regulating immune responses and protecting joint structures is also discussed. This review aims to evaluate the efficacy and potential clinical applications of antioxidant therapies in RA, emphasizing their role in mitigating oxidative damage and improving treatment outcomes. While preliminary findings are promising, further clinical trials are needed to establish standardized dosing, long-term safety, and their integration into current RA treatment protocols.

Hydrogen-oxygen mixture inhalation as an adjunctive treatment to home-based exercise in older patients with knee osteoarthritis: an open-label, blinded-endpoint, randomized controlled trial

Objective

Knee osteoarthritis (KOA) is a degenerative joint condition, leading to disability and diminished quality of life. Molecular hydrogen has been proven to have antioxidant and anti-inflammatory properties, but few studies have investigated its effects on osteoarthritis. Our study aims to assess the therapeutic potential of hydrogen-oxygen mixture (H2-O2) inhalation for KOA.

Methods

In this randomized controlled trial, eligible elderly KOA patients were randomly assigned to either Group H or Group C. Both groups participated in a 12-week home-based exercise (HBE) program, which included knee-joint exercises and health education. Group H additionally received H2-O2 inhalation for 60 min per day over 2 weeks, while Group C did not. The primary outcome was measured using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcomes included inflammation levels (hs-CRP, NLR, PLR, LMR), Chair Stand Test (CST), Timed Up and Go (TUG), 36-item short-form health survey (SF-36), Exercise Adherence Rating Scale (EARS), and adverse events.

Results

A total of 121 subjects were enrolled, with an average age of 81.2 years, and 80.2% were female. The between-group mean difference in the WOMAC total score was -5.2 (95% CI -12.1 to 1.7, P = 0.140) at week 12, with Group H showing an improvement of -22.9 (95% CI -26.3 to -19.6, P < 0.001) and Group C showing an improvement of -19.4 (95% CI -22.7 to -16.0, P < 0.001) compared to baseline, revealing a significant group × time interaction (F (3, 356.034) = 14.425, P < 0.001). No significant differences were observed between both groups at week 12 in CST, TUG, SF-36 scores, EARS scores, or the incidence of adverse events.

Conclusion

Although clinical significance was not achieved, H2-O2 inhalation alleviated KOA symptoms and enhanced functional activity in elderly patients undergoing the HBE program during the initial 2 weeks. However, its sustained effects on improving KOA symptoms were not observed.

Pharmacokinetics of Hydrogen During Hydrogen-Saturated Saline Infusion in Pigs

Background: Hydrogen gas (H2) has been shown to be effective in the treatment of various clinical conditions, from acute illnesses to chronic illnesses. However, its clinical indications and the corresponding appropriate hydrogen delivery methods have yet to be determined. This is due to the fact that the pharmacokinetics and pharmacodynamics of hydrogen in each delivery method have not been experimentally proven. Here, we verified the pharmacokinetics of hydrogen after the infusion of hydrogen-saturated saline. Methods: Hydrogen-saturated saline was prepared and checked for sterility and component specifications. Hydrogen-saturated saline was administered intravenously (125 mL/h) through the left internal jugular vein of pigs, and the blood hydrogen concentration was measured over time. Results: It was confirmed that hydrogen can be safely mixed under pressure into intravenous solutions (pharmaceutical products) without the contamination of foreign substances by using a needle-less vial access cannula. No change in the PH or composition of the solution was observed due to hydrogen filling. The hydrogen concentrations of blood samples collected from the left internal jugular vein 3 cm to the heart from the tip of the infusion line were 6.4 (30 min), 4.7 (60 min), 4.9 (90 min), and 5.3 (120 min) ppb w/w, respectively. The hydrogen concentrations of blood samples collected from the right atrium were 0.7 (30 min), 0.5 (60 min), 0.7 (90 min), and 0.7 (120 min) ppb, respectively. The hydrogen concentration of blood samples collected from the right internal carotid artery were 0.1 (pre), 0.2 (30 min), 0.3 (60 min), 0.0 (90 min), and 0.0 (120 min) ppb w/w, respectively. Conclusions: We confirmed that hydrogen could be safely pressurized and filled into intravenous (pharmaceutical) solution without contamination by foreign objects using a needle-free vial access cannula. When saturated hydrogen saline was dripped intravenously, almost all of the hydrogen was expelled during its passage through the lungs and could not be supplied to the arterial side.

Molecular Hydrogen Therapy-A Review on Clinical Studies and Outcomes

With its antioxidant properties, hydrogen gas (H2) has been evaluated in vitro, in animal studies and in human studies for a broad range of therapeutic indications. A simple search of "hydrogen gas" in various medical databases resulted in more than 2000 publications related to hydrogen gas as a potential new drug substance. A parallel search in clinical trial registers also generated many hits, reflecting the diversity in ongoing clinical trials involving hydrogen therapy. This review aims to assess and discuss the current findings about hydrogen therapy in the 81 identified clinical trials and 64 scientific publications on human studies. Positive indications have been found in major disease areas including cardiovascular diseases, cancer, respiratory diseases, central nervous system disorders, infections and many more. The available administration methods, which can pose challenges due to hydrogens' explosive hazards and low solubility, as well as possible future innovative technologies to mitigate these challenges, have been reviewed. Finally, an elaboration to discuss the findings is included with the aim of addressing the following questions: will hydrogen gas be a new drug substance in future clinical practice? If so, what might be the administration form and the clinical indications?

Molecular Hydrogen Prevents Osteoclast Activation in a Glucocorticoid-Induced Osteoporosis Zebrafish Scale Model

Antioxidants represent a powerful tool for many human diseases and, in particular, molecular hydrogen has unique characteristics that make it a very promising therapeutic agent against osteoporosis. Zebrafish scales offer an innovative model in which new therapeutic approaches against secondary osteoporosis are tested. Scale bone loss obtained by prednisolone (PN) treatment is characterized by increased osteoclast activity and decreased osteoblast activity highlighted with bone enzymatic assays. We used this read-out system to test the therapeutic effects of hydrogen-rich water (HRW), an innovative antioxidant approach. HRW prevented osteoclast activation and bone loss in PN-treated fish scales, as verified by both biochemical and histochemical tartrate-resistant alkaline phosphatase assays. On the other hand, HRW treatment did not prevent PN-dependent osteoblast suppression, as measured by alkaline phosphatase activity. Moreover, HRW treatment did not facilitate the reparation of resorption lacunae induced in scales by PN. Our study highlighted a specific effect of HRW on adult osteoclast activity but not in osteoblasts, introducing an intriguing new antioxidant preventive approach against osteoporosis.

A double-blinded, randomized controlled clinical trial of hydrogen inhalation therapy for idiopathic sudden sensorineural hearing loss

Background

Hydrogen (H₂) has been reported to be effective in reducing hearing loss due to several causes in animal studies. However, no study has examined the effectiveness of H₂ in treating hearing loss in humans. Thus, we investigated whether H₂ is effective for the treatment of idiopathic sudden sensorineural hearing loss (ISSNHL).

Materials and methods

We conducted a double-blind randomized controlled trial at six hospitals between June 2019 and March 2022. The study protocol and trial registration have been published in the Japan Registry of Clinical Trials (jRCT, No. jRCTs06119004). We randomly assigned patients with ISSNHL to receive either H₂ (H₂ group) or air as a placebo (control group) through inhalation combined with the administration of systemic glucocorticoids and prostaglandin E1. The primary outcome was the hearing threshold and changes in hearing threshold 3 months after therapy. In contrast, the secondary outcomes included the proportion of patients with a good prognosis (complete recovery or marked improvement).

Results

Sixty-five patients with ISSNHL (31 and 34 in the H₂ and control groups, respectively) were included in this study. The hearing threshold 3 months after treatment was not significantly different between the groups; 39.0 decibels (dB) (95% confidence interval [CI]: 28.7-49.3) and 49.5 dB (95% CI: 40.3-58.7) in the H₂ and control groups, respectively. In contrast, the changes in hearing threshold 3 months after treatment was 32.7 dB (95% CI: 24.2-41.3) and 24.2 dB (95% CI: 18.1-30.3) in the H₂ and control groups, respectively. Consequently, the changes in hearing threshold were significantly better in the H₂ group than in the control group (P = 0.048). However, no adverse effects due to the inhalation of H₂ gas have been reported.

Conclusion

This is the first study to investigate the efficacy of H₂ for the treatment of ISSNHL in humans. The results suggest that H₂ therapy may be effective for ISSNHL treatment.

Clinical trial registration

[https://jrct.niph.go.jp/re/reports/detail/10442], identifier [jRCTs06119004].

NIR-photocatalytic regulation of arthritic synovial microenvironment

Synovial microenvironment (SME) plays a vital role in the formation of synovial pannus and the induction of cartilage destruction in arthritis. In this work, a concept of the photocatalytic regulation of SME is proposed for arthritis treatment, and monodispersive hydrogen-doped titanium dioxide nanorods with a rutile single-crystal structure are developed by a full-solution method to achieve near infrared-photocatalytic generation of hydrogen molecules and simultaneous depletion of overexpressed lactic acid (LA) for realizing SME regulation in a collagen-induced mouse model of rheumatoid arthritis. Mechanistically, locally generated hydrogen molecules scavenge overexpressed reactive oxygen species to mediate the anti-inflammatory polarization of macrophages, while the simultaneous photocatalytic depletion of overexpressed LA inhibits the inflammatory/invasive phenotypes of synoviocytes and macrophages and ameliorates the abnormal proliferation of synoviocytes, thereby remarkably preventing the synovial pannus formation and cartilage destruction. The proposed catalysis-mediated SME regulation strategy will open a window to realize facile and efficient arthritis treatment.

Hydrogen Gas Inhalation Attenuates Acute Impulse Noise Trauma: A Preclinical In Vivo Study

OBJECTIVE

Molecular hydrogen (H₂) has shown therapeutic potential in several oxidative stress-related conditions in humans, is well-tolerated, and is easily administered via inhalation.The aim of this preclinical in vivo study was to investigate whether impulse noise trauma can be prevented by H₂ when inhaled immediately after impulse noise exposure.

METHODS

Guinea pigs (n = 26) were subjected to impulse noise (n = 400; 156 dB SPL; 0.33/s; n = 11; the Noise group), to impulse noise immediately followed by H₂ inhalation (2 mol%; 500 ml/min; 1 hour; n = 10; the Noise + H₂ group), or to H₂ inhalation (n = 5; the H₂ group). The acoustically evoked ABR threshold at 3.15, 6.30, 12.5, 20.0, and 30.0 kHz was assessed before and 4 days after impulse noise and/or H₂ exposure. The cochleae were harvested after the final ABR assessment for quantification of hair cells.

RESULTS

Noise exposure caused ABR threshold elevations at all frequencies (median 35, 35, 30, 35, and 35 dB SPL, the Noise group; 20, 25, 10, 13, and 20 dB SPL, the Noise + H₂ group; P < .05) but significantly less so in the Noise + H₂ group (P < .05). Outer hair cell (OHC) loss was in the apical, mid, and basal regions 8.8%, 53%, and 14% in the Noise group and 3.5%, 22%, and 1.2% in the Noise + H₂ group. The corresponding inner hair cell (IHC) loss was 0.1%, 14%, and 3.5% in the Noise group and 0%, 2.8%, and 0% in the Noise + H₂ group. The difference between the groups was significant in the basal region for OHCs (P = .003) and apical (P = .033) and basal (P = .048) regions for IHCs.

CONCLUSIONS

Acute acoustic trauma can be reduced by H₂ when inhaled immediately after impulse noise exposure.

Heterojunction Nanomedicine

Exogenous stimulation catalytic therapy has received enormous attention as it holds great promise to address global medical issues. However, the therapeutic effect of catalytic therapy is seriously restricted by the fast charge recombination and the limited utilization of exogenous stimulation by catalysts. In the past few decades, many strategies have been developed to overcome the above serious drawbacks, among which heterojunctions are the most widely used and promising strategy. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction nanomedicine, such as semiconductor-semiconductor heterojunctions (including type I, type II, type III, PN, and Z-scheme junctions) and semiconductor-metal heterojunctions (including Schottky, Ohmic, and localized surface plasmon resonance-mediated junctions). The catalytic mechanisms and properties of the above junction systems are also discussed in relation to biomedical applications, especially cancer treatment and sterilization. This review concludes with a summary of the challenges and some perspectives on future directions in this exciting and still evolving field of research.

Molecular Hydrogen as Medicine: An Assessment of Administration Methods

Since the late 18th century, molecular hydrogen (H2) has been shown to be well tolerated, firstly in animals, and then in humans. However, although research into the beneficial effects of molecular hydrogen in both plant and mammalian physiology is gaining momentum, the idea of utilising this electrochemically neutral and non-polar diatomic compound for the benefit of health has yet to be widely accepted by regulatory bodies worldwide. Due to the precise mechanisms of H2 activity being as yet undefined, the lack of primary target identification, coupled with difficulties regarding administration methods (e.g., dosage and dosage frequencies, long-term effects of treatment, and the patient’s innate antioxidant profile), there is a requirement for H2 research to evidence how it can reasonably and most effectively be incorporated into medical practice. This review collates and assesses the current information regarding the many routes of molecular hydrogen administration in animals and humans, whilst evaluating how targeted delivery methods could be integrated into a modern healthcare system.

Molecular Hydrogen: A Promising Adjunctive Strategy for the Treatment of the COVID-19

Coronavirus disease 2019 (COVID-19) is an acute respiratory disease caused by a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has no specific and effective treatment. The pathophysiological process of the COVID-19 is an excessive inflammatory response after an organism infects with a virus. Inflammatory storms play an important role in the development of the COVID-19. A large number of studies have confirmed that hydrogen has a therapeutic effect on many diseases via inhibiting excessive inflammatory cells and factors. Recently, a study led by the Academician Zhong Nanshan in China on the treatment of the patients with the COVID-19 by inhalation of a mixed gas composed of hydrogen and oxygen has attracted widespread international attention and hydrogen therapy has also been included in a new treatment plan for the COVID-19 in China. This study mainly describes the mechanism of occurrence of the COVID-19, summarizes the therapeutic effects and underlying mechanisms of hydrogen on the critical disease, and analyzes the feasibility and potential therapeutic targets of hydrogen for the treatment of the COVID-19.

Molecular Hydrogen: Is This a Viable New Treatment for Plants in the UK?

Despite being trialed in other regions of the world, the use of molecular hydrogen (H₂) for enhanced plant growth and the postharvest storage of crops has yet to be widely accepted in the UK. The evidence that the treatment of plants and plant products with H₂ alleviates plant stress and slows crop senescence continues to grow. Many of these effects appear to be mediated by the alteration of the antioxidant capacity of plant cells. Some effects seem to involve heme oxygenase, whilst the reduction in the prosthetic group Fe³⁺ is also suggested as a mechanism. Although it is difficult to use as a gaseous treatment in a field setting, the use of hydrogen-rich water (HRW) has the potential to be of significant benefit to agricultural practices. However, the use of H₂ in agriculture will only be adopted if the benefits outweigh the production and application costs. HRW is safe and relatively easy to use. If H₂ gas or HRW are utilized in other countries for agricultural purposes, it is tempting to suggest that they could also be widely used in the UK in the future, particularly for postharvest storage, thus reducing food waste.

The Efficacy of Antioxidative Stress Therapy on Oxidative Stress Levels in Rheumatoid Arthritis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

Objective

To explore the efficacy of antioxidative stress therapy on oxidative stress levels in rheumatoid arthritis (RA) by a systematic review and meta-analysis of randomized controlled trials.

Methods

Chinese and English databases such as PubMed, Embase, China National Knowledge Infrastructure (CNKI), and China Biomedical Literature were searched, mainly searching for clinical randomized controlled trials of antioxidant therapy for rheumatoid arthritis. The search time is from the establishment of the database to July 2021. Two researchers independently carried out literature search, screening, and data extraction. The bias risk tool provided by the Cochrane Collaboration was used to evaluate the bias risk of all the included literature, and the RevMan 5.3 software was used for meta-analysis.

Results

A total of 24 RCTs (28 records) and 1277 participants were included. The time span of randomized controlled trials (RCTs) is from 1986 to 2020. These RCTs involve 14 types of antioxidants or antioxidant therapies, and these therapies have varying degrees of improvement on oxidative stress in RA patients. The summary results showed that the MDA in the experiment group is lower (SMD -0.82, 95% CI -1.35 to -0.28, P = 0.003). The difference of TAC, SOD, NO, GPx, CAT, and GSH between two groups was of no statistical significance (TAC (SMD 0.27, 95% CI -0.21 to 0.75, P = 0.27), SOD (SMD 0.12, 95% CI -0.16 to 0.40, P = 0.41), NO (SMD -2.03, 95% CI -4.22 to 0.16, P = 0.07), GPx (SMD 0.24, 95% CI -0.07 to 0.54, P = 0.13), CAT (SMD 2.95, 95% CI -2.6 to 8.51, P = 0.30), and GSH (SMD 2.46, 95% CI -0.06 to 4.98, P = 0.06)). For adverse events, the summary results showed that the difference was of no statistical significance (RR 1.16, 95% CI 0.79 to 1.71, P = 0.45). In addition, antioxidant therapy has also shown improvement in clinical efficacy indexes (number of tender joints, number of swollen joints, DAS28, VAS, and HAQ) and inflammation indexes (ESR, CRP, TNF-α, and IL6) for RA patients.

Conclusion

The existing evidence shows potential benefits, mainly in reducing MDA and increasing TAC and GSH in some subgroups. However, more large samples and higher quality RCTs are needed to provide high-quality evidence, so as to provide more clinical reference information for the antioxidant treatment of RA.

Molecular hydrogen is comparable to sulfasalazine as a treatment for DSS-induced colitis in mice

Colitis is an inflammatory condition of the bowels associated with abdominal pain, diarrhea, fatigue, and fever. Its etiology is multifactorial but related to the overproduction of inflammatory and oxidative mediators. There is currently no cure for this disease, and drugs used to manage it often have deleterious side effects. H₂ is recognized as having anti-inflammatory and antioxidant effects, which may qualify it as a novel therapeutic for colitis. We induced an acute model of colitis in mice by administering dextran sulfate sodium (DSS) in drinking water for seven days. Mice were divided into five groups (n=6); normal, colitis, H₂-treated colitis, sulfasalazine-treated colitis, and H₂ plus sulfasalazine-treated colitis. From days three to ten, mice were given H₂, sulfasalazine, or both. H₂ was administered via dissolving a hydrogen-generating tablet in water to make hydrogen-rich water (HRW), which was ingested ad libitum and via oral gavage (200 μL). The Disease Activity Index (DAI), histological changes, and markers of inflammation and oxidative stress were assessed. HRW and sulfasalazine significantly improved bodyweight, DAI, mucosal damage, crypt loss, and spleen weight compared to control. Both treatments significantly decreased inflammation (high-sensitive C-reactive protein) and restored redox balance (total thiol, superoxide dismutase, catalase activity). There was a trend for the combination treatment to be more effective than either HRW or sulfasalazine alone. Furthermore, HRW tended to be as effective as, and often more effective than, sulfasalazine. HRW may serve as a therapeutic for ameliorating DSS-induced colitis in mice.

Molecular Hydrogen as a Potential Clinically Applicable Radioprotective Agent

Although ionizing radiation (radiation) is commonly used for medical diagnosis and cancer treatment, radiation-induced damages cannot be avoided. Such damages can be classified into direct and indirect damages, caused by the direct absorption of radiation energy into DNA and by free radicals, such as hydroxyl radicals (•OH), generated in the process of water radiolysis. More specifically, radiation damage concerns not only direct damages to DNA, but also secondary damages to non-DNA targets, because low-dose radiation damage is mainly caused by these indirect effects. Molecular hydrogen (H₂) has the potential to be a radioprotective agent because it can selectively scavenge •OH, a reactive oxygen species with strong oxidizing power. Animal experiments and clinical trials have reported that H₂ exhibits a highly safe radioprotective effect. This paper reviews previously reported radioprotective effects of H₂ and discusses the mechanisms of H₂, not only as an antioxidant, but also in intracellular responses including anti-inflammation, anti-apoptosis, and the regulation of gene expression. In doing so, we demonstrate the prospects of H₂ as a novel and clinically applicable radioprotective agent.

Randomized, crossover clinical efficacy trial in humans and mice on tear secretion promotion and lacrimal gland protection by molecular hydrogen

The incidence of dry eye disease is increasing worldwide because of the aging population and increasing use of information technology. Dry eye disease manifests as tear-layer instability and inflammation caused by osmotic hypersensitization in tear fluids; however, to our knowledge, no agent that treats both pathologies simultaneously is available. Molecular hydrogen (H₂) is known to be effective against various diseases; therefore, we aimed to elucidate the effects of H₂ on tear dynamics and the treatment of dry eye disease. We revealed that administering a persistent H₂-generating supplement increased the human exhaled H₂ concentration (p < 0.01) and improved tear stability (p < 0.01) and dry eye symptoms (p < 0.05) significantly. Furthermore, H₂ significantly increased tear secretion in healthy mice (p < 0.05) and significantly suppressed tear reduction in a murine dry eye model (p = 0.007). H₂ significantly and safely improved tear stability and dry eye symptoms in a small exploratory group of 10 human subjects, a subset of whom reported dry eye symptoms prior to treatment. Furthermore, it increased tear secretion rapidly in normal mice. Therefore, H₂ may be a safe and effective new treatment for dry eye disease and thus larger trials are warranted.

Magnesium-Based Micromotors as Hydrogen Generators for Precise Rheumatoid Arthritis Therapy

Hydrogen therapy is an emerging and highly promising strategy for the treatment of inflammation-related diseases. However, nonpolarity and low solubility of hydrogen under the physiological conditions results in a limited therapeutic effect. Herein, we develop a biocompatible magnesium micromotor coated with hyaluronic acid as a hydrogen generator for precise rheumatoid arthritis management. The hydrogen bubbles generated locally not only function as a propellant for the motion but also function as the active ingredient for reactive oxygen species (ROS) and inflammation scavenging. Under ultrasound guidance, the micromotors are injected intra-articularly, and the dynamics of the micromotors can be visualized. By scavenging ROS and inflammation via active hydrogen, the oxidative stress is relieved and the levels of inflammation cytokines are reduced by our micromotors, showing prominent therapeutic efficacy in ameliorating joint damage and suppressing the overall arthritis severity toward a collagen-induced arthritis rat model. Therefore, our micromotors show great potential for the therapy of rheumatoid arthritis and further clinical transformation.

Potential Therapeutic Applications of Hydrogen in Chronic Inflammatory Diseases: Possible Inhibiting Role on Mitochondrial Stress

Mitochondria are the largest source of reactive oxygen species (ROS) and are intracellular organelles that produce large amounts of the most potent hydroxyl radical (·OH). Molecular hydrogen (H₂) can selectively eliminate ·OH generated inside of the mitochondria. Inflammation is induced by the release of proinflammatory cytokines produced by macrophages and neutrophils. However, an uncontrolled or exaggerated response often occurs, resulting in severe inflammation that can lead to acute or chronic inflammatory diseases. Recent studies have reported that ROS activate NLRP3 inflammasomes, and that this stimulation triggers the production of proinflammatory cytokines. It has been shown in literature that H₂ can be based on the mechanisms that inhibit mitochondrial ROS. However, the ability for H₂ to inhibit NLRP3 inflammasome activation via mitochondrial oxidation is poorly understood. In this review, we hypothesize a possible mechanism by which H₂ inhibits mitochondrial oxidation. Medical applications of H₂ may solve the problem of many chronic inflammation-based diseases, including coronavirus disease 2019 (COVID-19).

Hydrogen Is Promising for Medical Applications

Hydrogen (H2) is promising as an energy source for the next generation. Medical applications using H2 gas can be also considered as a clean and economical technology. Since the H2 gas based on electrolysis of water production has potential to expand the medical applications, the technology has been developed in order to safely dilute it and to supply it to the living body by inhalation, respectively. H2 is an inert molecule which can scavenge the highly active oxidants including hydroxyl radical (·OH) and peroxynitrite (ONOO−), and which can convert them into water. H2 is clean and causes no adverse effects in the body. The mechanism of H2 is different from that of traditional drugs because it works on the root of many diseases. Since H2 has extensive and various effects, it may be called a “wide spectrum molecule” on diseases. In this paper, we reviewed the current medical applications of H2 including its initiation and development, and we also proposed its prospective medical applications. Due to its marked efficacy and no adverse effects, H2 will be a next generation therapy candidate for medical applications.

Water-Splitting Based and Related Therapeutic Effects: Evolving Concepts, Progress, and Perspectives

Water-splitting has been extensively studied especially for energy applications. It is often not paid with enough attention for biomedical applications. In fact, several innovative breakthroughs have been achieved in the past few years by employing water-splitting for treating cancer and other diseases. Interestingly, among these important works, only two reports have mentioned the term "water-splitting." For this reason, the importance of water-splitting for biomedical applications is significantly underestimated. This progress work is written with the aims to explain and summarize how the principle of water-splitting is employed to achieve therapeutic results not offered by conventional approaches. It is expected that this progress report will not only explain the importance of water-splitting to scientists in the biomedical fields, it should also draw attention from scientists working on energy applications of water-splitting.

Myalgic encephalomyelitis/chronic fatigue syndrome: From pathophysiological insights to novel therapeutic opportunities

Myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) is a common and disabling condition with a paucity of effective and evidence-based therapies, reflecting a major unmet need. Cognitive behavioural therapy and graded exercise are of modest benefit for only some ME/CFS patients, and many sufferers report aggravation of symptoms of fatigue with exercise. The presence of a multiplicity of pathophysiological abnormalities in at least the subgroup of people with ME/CFS diagnosed with the current international consensus "Fukuda" criteria, points to numerous potential therapeutic targets. Such abnormalities include extensive data showing that at least a subgroup has a pro-inflammatory state, increased oxidative and nitrosative stress, disruption of gut mucosal barriers and mitochondrial dysfunction together with dysregulated bioenergetics. In this paper, these pathways are summarised, and data regarding promising therapeutic options that target these pathways are highlighted; they include coenzyme Q₁₀, melatonin, curcumin, molecular hydrogen and N-acetylcysteine. These data are promising yet preliminary, suggesting hopeful avenues to address this major unmet burden of illness.

Effect of H2 treatment in a mouse model of rheumatoid arthritis-associated interstitial lung disease

Rheumatoid arthritis (RA)-associated interstitial lung disease (ILD), a primary cause of mortality in patients with RA, has limited treatment options. A previously established RA model in D1CC transgenic mice aberrantly expressed major histocompatibility complex class II genes in joints, developing collagen II-induced polyarthritis and anti-cyclic citrullinated peptide antibodies and interstitial pneumonitis, similar to those in humans. Molecular hydrogen (H₂ ) is an efficient antioxidant that permeates cell membranes and alleviates the reactive oxygen species-induced injury implicated in RA pathogenesis. We used D1CC mice to analyse chronic lung fibrosis development and evaluate H₂ treatment effects. We injected D1CC mice with type II collagen and supplied them with H₂ -rich or control water until analysis. Increased serum surfactant protein D values and lung densities images were observed 10 months after injection. Inflammation was patchy within the perilymphatic stromal area, with increased 8-hydroxy-2'-deoxyguanosine-positive cell numbers and tumour necrosis factor-α, BAX, transforming growth factor-β, interleukin-6 and soluble collagen levels in the lungs. Inflammatory and fibrotic changes developed diffusely within the perilymphatic stromal area, as observed in humans. H₂ treatment decreased these effects in the lungs. Thus, this model is valuable for studying the effects of H₂ treatment and chronic interstitial pneumonia pathophysiology in humans. H₂ appears to protect against RA-ILD by alleviating oxidative stress.

Hydrogen-producing milk to prevent reduction in tear stability in persons using visual display terminals

PURPOSE

To examine the effect of hydrogen (H₂)-producing milk, which induces H₂ production by intestinal microbiota, on the prevention of dry eye disease.

METHODS

A randomized, double-blind, placebo-controlled, parallel-group comparative study was conducted in humans. Of 118 candidates aged 20-60 years who were using visual display terminals daily, 54 subjects (mean age, 42.4 years) with mild-to-moderate dry eye symptoms, who were not dry eye patients based on the 2006 Japanese Diagnostic Criteria for Dry Eye, were included in the study. Subjects were assigned to the H₂-producing milk group or the placebo group. They were instructed to ingest the assigned test beverage once per day for three consecutive weeks. Breath H₂ concentration, fluorescein tear film breakup time (fTBUT), Schirmer's test, 8-OHdG concentration in tears, reported ocular symptoms using the dry eye-related QOL score questionnaire, and the visual analogue scale were assessed at weeks 0 and 3.

RESULTS

Change in fTBUT in the H₂-producing milk group was significantly greater than that in the placebo group. A significant decline in fTBUT was observed in the placebo group (p = 0.04), but not the H₂-producing group (p = 0.26). This phenomenon was strongly observed in females. We found a positive correlation between the change in fTBUT and net H₂ production, and a negative correlation between the change in 8-OHdG concentration and net H₂ production in young females.

CONCLUSIONS

H₂-producing milk appeared to retard the decline in tear stability and may prevent short fTBUT-type dry eye by decreasing oxidative stress in the lacrimal functional unit.

Hydrogen gas inhalation enhances alveolar macrophage phagocytosis in an ovalbumin-induced asthma model

BACKGROUND

Maintaining an airway clear of bacteria, foreign particles and apoptotic cells by alveolar macrophages is very essential for lung homeostasis. In asthma, the phagocytic capacity of alveolar macrophages is significantly reduced, which is thought to be associated with increased oxidative stress. Hydrogen (H₂) has been shown to exert potent antioxidant and anti-inflammatory effects, yet its effects on phagocytosis of alveolar macrophages are unknown. This study is aimed to evaluate the beneficial effects of hydrogen gas inhalation on alveolar macrophage phagocytosis in an ovalbumin (OVA)-induced murine asthma model.

METHODS

Female C57BL/6 mice were intraperitoneally sensitized with OVA before they were subject to airway challenge with aerosolized OVA. Hydrogen gas was delivered to the mice through inhalation twice a day (2 h once) for 7 consecutive days. Phagocytic function of alveolar macrophages isolated from bronchoalveolar lavage fluid was assessed by fluorescence-labeled Escherichia coli as well as flow cytometry.

RESULTS

Alveolar macrophages isolated from OVA-induced asthmatic mice showed decreased phagocytic capacity to Escherichia coli when compared with those of control mice. Defective phagocytosis in asthmatic mice was reversed by hydrogen gas inhalation. Hydrogen gas inhalation significantly alleviated OVA-induced airway hyperresponsiveness, inflammation and goblet cell hyperplasia, diminished T_H2 response and decreased IL-4 as well as IgE levels, reduced malondialdehyde (MDA) production and increased superoxide dismutase (SOD) activity. Concomitantly, hydrogen gas inhalation inhibited NF-κB activation and markedly activated Nrf2 pathway in OVA-induced asthmatic mice.

CONCLUSIONS

Our findings demonstrated that hydrogen gas inhalation enhanced alveolar macrophage phagocytosis in OVA-induced asthmatic mice, which may be associated with the antioxidant effects of hydrogen gas and the activation of the Nrf2 pathway.

Hydrogen gas inhalation protects against cigarette smoke-induced COPD development in mice

Background

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease with limited treatment options. Hydrogen (H₂) has been shown to be anti-oxidative and anti-inflammatory. This study aimed to evaluate the beneficial effects of H₂ inhalation on COPD development in mice.

Methods

A COPD mouse model was established in male C57BL mice by cigarette smoke (CS) exposure. The H₂ intervention was administered by atomisation inhalation. Lung functions were assessed by using Buxco lung function measurement system. The inflammatory cells were counted and the levels of IL-6 and KC in BALF were assayed with ELISA. The lung tissue was subjected to H&E or PAS or Masson's trichrome stain. Furthermore, 16HBE cells were used to evaluate the effects of H₂ on signaling change caused by hydrogen peroxide (H₂O₂). H₂O₂ was used to treat 16HBE cells with or without H₂ pretreatment. The IL-6 and IL-8 levels in cell culture medium were measured. The levels of phosphorylated ERK1/2 and nucleic NF-κB in lungs and 16HBE cells were determined.

Results

H₂ ameliorated CS-induced lung function decline, emphysema, inflammatory cell infiltration, small-airway remodelling, goblet-cell hyperplasia in tracheal epithelium and activated ERK1/2 and NF-κB in mouse lung. In 16HBE airway cells, H₂O₂ increased IL-6 and IL-8 secretion in conjunction with ERK1/2 and NF-κB activation. These changes were reduced by H₂ treatment.

Conclusions

These findings demonstrated that H₂ inhalation could inhibit CS-induced COPD development in mice, which is associated with reduced ERK1/2 and NF-κB-dependent inflammatory responses.

Positive effects of hydrogen-water bathing in patients of psoriasis and parapsoriasis en plaques

Psoriasis and parapsoriasis en plaques are chronic inflammatory skin diseases, both representing therapeutic challenge in daily practice and adversely affecting the quality of life. Reactive oxygen species (ROS) has been evidenced to be involved in the pathogenesis of the chronic inflammatory diseases. We now report that hydrogen water, an effective ROS scavenger, has significant and rapid improvement in disease severity and quality of life for patients with psoriasis and parapsoriasis en plaques. At week 8, our parallel-controlled trial revealed 24.4% of patients (10/41) receiving hydrogen-water bathing achieved at least 75% improvement in Psoriasis Area Severity Index (PASI) score compared with 2.9% of patients (1/34) of the control group (Pc = 0.022, OR = 0.094, 95%CI = [0.011, 0.777]). Of patients, 56.1% (23/41) who received bathing achieved at least 50% improvement in PASI score compared with only 17.7%(6/34) of the control group (P = 0.001, OR = 0.168, 95%CI = [0.057, 0.492]). The significant improvement of pruritus was also observed (P = 3.94 × 10⁻⁴). Besides, complete response was observed in 33.3% of patients (2/6) of parapsoriasis en plaques and partial response in 66.7% (4/6) at week 8. Our findings suggested that hydrogen-water bathing therapy could fulfill the unmet need for these chronic inflammatory skin diseases.

Prevention of ischemia-induced hearing loss by intravenous administration of hydrogen-rich saline in gerbil

OBJECTIVE

Hydrogen-rich water, which is a potent antioxidant agent, was investigated for its protective effects against ischemic damage of the cochlea in gerbils.

METHODS

The animals were subjected to transient cochlear ischemia by occluding the bilateral vertebral arteries for l5min. Five milliliters of hydrogen-rich saline was then intravenously administered immediately after the insult. Saline without hydrogen was used as a control. Effects of hydrogen were evaluated using the auditory brainstem response (ABR) and histological studies of the inner ear.

RESULTS

In non-ischemia animals, ABR thresholds and histological findings of the cochlea did not change by administration of saline or hydrogen-rich saline. In contrast, transient cochlear ischemia caused a 24.2±3.8dB increase in the ABR threshold at 8kHz, and a decrease of 14.1%±1.8% in the number of inner hair cells (IHCs) at the basal turn on day 7. Ischemic damage was more severe at 16 and 32kHz. When the animals were treated with hydrogen-rich saline, cochlear damage was significantly reduced: the increase in ABR threshold was 11.7±2.6dB at 8kHz and the IHC loss was 7.5%±2.1% at the basal turn on day 7. The effects of hydrogen-rich saline were more prominent at higher frequencies.

CONCLUSIONS

Intravenous administration of hydrogen-rich saline was effective in preventing acute hearing loss due to transient cochlear ischemia.

Molecular hydrogen: a preventive and therapeutic medical gas for various diseases

Since the 2007 discovery that molecular hydrogen (H2) has selective antioxidant properties, multiple studies have shown that H2 has beneficial effects in diverse animal models and human disease. This review discusses H2 biological effects and potential mechanisms of action in various diseases, including metabolic syndrome, organ injury, and cancer; describes effective H2 delivery approaches; and summarizes recent progress toward H2 applications in human medicine. We also discuss remaining questions in H2 therapy, and conclude with an appeal for a greater role for H2 in the prevention and treatment of human ailments that are currently major global health burdens. This review makes a case for supporting hydrogen medicine in human disease prevention and therapy.

Hydrogen-rich saline prevents bone loss in diabetic rats induced by streptozotocin

PURPOSE

As an antioxidant molecule, hydrogen has been received much more attention and reported to be used as the treatment strategy for various diseases. In this study, we hypothesize that systemic delivery of hydrogen saline water may improve the reservation of bone tissue in the tibias and femurs of osteoporotic rats caused by diabetes mellitus (DM), which is characterized by increased levels of oxidative stress and overproducing reactive oxygen species (ROS).

METHODS

The animals were divided into three groups of 12 animals and lavaged with normal saline (normal control and DM), or hydrogen saline water (DM + HRS). General status, blood glucose level, tibial and femoral mechanical strength, and micro-CT scans of the proximal tibia were recorded and analyzed.

RESULTS

After 12 weeks, the glucose level was significantly decreased in the DM + HRS group compared with that of the DM group. Micro-CT scans showed that bone volume/total volume, connectivity density, trabecular thickness, and trabecular number were significantly increased compared with the DM group. Mechanical results of energy, stiffness and elastic modulus in the DM + HRS group were significantly higher than in the other groups for the tibia and femur.

CONCLUSIONS

The results indicate that the systemic delivery of hydrogen saline water, which is safe and well tolerated, preserves bone volume and decreases fracture risks in streptozotocin-induced diabetic status rats, whose bone structure or inherent material properties of bone tissues are changed.

Adiponectin exerts a potent anti-arthritic effect and insulin resistance in collagen-induced arthritic rats

AIM

Previous research has shown that adiponectin (AD) induces severe insulin resistance (IR) and exhibits pro-inflammatory effect, so it could serve as a useful risk biomarker in rheumatoid arthritis (RA). The present study aims to evaluate the effect of AD on IR and anti-arthritis in collagen-induced arthritic (CIA) rats.

METHOD

After immunization with bovine type II collagen (CII), Wistar rats were administered with AD (60 μg/kg/day) or saline into the ankle joint cavity of the left hind leg for 15 days. The severity of arthritis was clinically and histologically assessed. Arthritis score was recorded every other day for each paw. Paw volume was measured on alternate days to monitor the progression of the disease in the arthritic control group. Tumor necrosis factor (TNF)-α, interleukin (IL)-1, AD, insulin and fasting glucose were measured in sera. Histopathology of joint synovial tissues was also examined.

RESULTS

Treatment with AD resulted in significantly delayed onset of arthritis as well as decreased clinical arthritis and histopathological severity scores. AD reduced both serum fasting glucose, TNF-α, IL-1 and IR. Histological analysis confirmed treatment with AD suppressed joint synovial inflammation and immunohistochemical expression of TNF-α compared to the CIA group. Surprisingly, adiponectin levels measured by enzyme-linked immunosorbent assay in serum were significantly increased in CIA rats compared to the normal group.

CONCLUSIONS

Adiponectin might display anti-inflammatory effects. These results suggest that AD may be a potential immunosuppressant for the treatment of RA linked to metabolic disease.

Anti-oxidant and anti-inflammatory effects of hydrogen-rich water alleviate ethanol-induced fatty liver in mice

AIM

To investigate the effects of hydrogen-rich water (HRW) treatment on prevention of ethanol (EtOH)-induced early fatty liver in mice.

METHODS

In vitro reduction of hydrogen peroxide by HRW was determined with a chemiluminescence system. Female mice were randomly divided into five groups: control, EtOH, EtOH + silymarin, EtOH + HRW and EtOH + silymarin + HRW. Each group was fed a Lieber-DeCarli liquid diet containing EtOH or isocaloric maltose dextrin (control diet). Silymarin was used as a positive control to compare HRW efficacy against chronic EtOH-induced hepatotoxicity. HRW was freshly prepared and given at a dosage of 1.2 mL/mouse trice daily. Blood and liver tissue were collected after chronic-binge liquid-diet feeding for 12 wk.

RESULTS

The in vitro study showed that HRW directly scavenged hydrogen peroxide. The in vivo study showed that HRW increased expression of acyl ghrelin, which was correlated with food intake. HRW treatment significantly reduced EtOH-induced increases in serum alanine aminotransferase, aspartate aminotransferase, triglycerol and total cholesterol levels, hepatic lipid accumulation and inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-6. HRW attenuated malondialdehyde level, restored glutathione depletion and increased superoxide dismutase, glutathione peroxidase and catalase activities in the liver. Moreover, HRW reduced TNF-α and IL-6 levels but increased IL-10 and IL-22 levels.

CONCLUSION

HRW protects against chronic EtOH-induced liver injury, possibly by inducing acyl ghrelin to suppress the pro-inflammatory cytokines TNF-α and IL-6 and induce IL-10 and IL-22, thus activating antioxidant enzymes against oxidative stress.

Preventive and therapeutic application of molecular hydrogen in situations with excessive production of free radicals

Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals may act preventively or therapeutically. A number of substances that preferentially react with free radicals can serve as scavengers, thus increasing the internal capacity/activity of endogenous antioxidants and protecting cells and tissues against oxidative damage. Molecular hydrogen (H(2)) reacts with strong oxidants, such as hydroxyl and nitrosyl radicals, in the cells, that enables utilization of its potential for preventive and therapeutic applications. H(2) rapidly diffuses into tissues and cells without affecting metabolic redox reactions and signaling reactive species. H(2) reduces oxidative stress also by regulating gene expression, and functions as an anti-inflammatory and anti-apoptotic agent. There is a growing body of evidence based on the results of animal experiments and clinical observations that H(2) may represent an effective antioxidant for the prevention of oxidative stress-related diseases. Application of molecular hydrogen in situations with excessive production of free radicals, in particular, hydroxyl and nitrosyl radicals is relatively simple and effective, therefore, it deserves special attention.

Molecular hydrogen suppresses activated Wnt/β-catenin signaling

Molecular hydrogen (H₂) is effective for many diseases. However, molecular bases of H₂ have not been fully elucidated. Cumulative evidence indicates that H₂ acts as a gaseous signal modulator. We found that H₂ suppresses activated Wnt/β-catenin signaling by promoting phosphorylation and degradation οf β-catenin. Either complete inhibition of GSK3 or mutations at CK1- and GSK3-phosphorylation sites of β-catenin abolished the suppressive effect of H₂. H₂ did not increase GSK3-mediated phosphorylation of glycogen synthase, indicating that H₂ has no direct effect on GSK3 itself. Knock-down of adenomatous polyposis coli (APC) or Axin1, which form the β-catenin degradation complex, minimized the suppressive effect of H₂ on β-catenin accumulation. Accordingly, the effect of H₂ requires CK1/GSK3-phosphorylation sites of β-catenin, as well as the β-catenin degradation complex comprised of CK1, GSK3, APC, and Axin1. We additionally found that H₂ reduces the activation of Wnt/β-catenin signaling in human osteoarthritis chondrocytes. Oral intake of H₂ water tended to ameliorate cartilage degradation in a surgery-induced rat osteoarthritis model through attenuating β-catenin accumulation. We first demonstrate that H₂ suppresses abnormally activated Wnt/β-catenin signaling, which accounts for the protective roles of H₂ in a fraction of diseases.

Molecular hydrogen stimulates the gene expression of transcriptional coactivator PGC-1α to enhance fatty acid metabolism

We previously reported that molecular hydrogen (H₂) acts as a novel antioxidant to exhibit multiple functions. Moreover, long-term drinking of H₂-water (water infused with H₂) enhanced energy expenditure to improve obesity and diabetes in db/db mice accompanied by the increased expression of fibroblast growth factor 21 (FGF21) by an unknown mechanism. H₂ was ingested by drinking of H₂-water or by oral administration of an H₂-producing material, MgH₂. The comprehensive gene expression profile in the liver of db/db mice was analyzed by DNA microarray. The molecular mechanisms underlying the gene expression profile was investigated using cultured HepG2 cells. Moreover, the effects on lifespan of drinking H₂-water were examined using wild-type mice that were fed a fatty diet. Pathway analyses based on comprehensive gene expression revealed the increased expression of various genes involved in fatty acid and steroid metabolism. As a transcription pathway, the PPARα signaling pathway was identified to upregulate their genes by ingesting H₂. As an early event, the gene expression of PGC-1α was transiently increased, followed by increased expression of FGF21. The expression of PGC-1α might be regulated indirectly through sequential regulation by H₂, 4-hydroxy-2-nonenal, and Akt/FoxO1 signaling, as suggested in cultured cell experiments. In wild-type mice fed the fatty diet, H₂-water improved the level of plasma triglycerides and extended their average of lifespan. H₂ induces expression of the PGC-1α gene, followed by stimulation of the PPARα pathway that regulates FGF21, and the fatty acid and steroid metabolism.

Hydrogen therapy: from mechanism to cerebral diseases

The medicinal value of hydrogen (H₂) was ignored prior to research illustrating that inhalation of 2% H₂ can significantly decrease the damage of cerebral ischemia/reperfusion caused by oxidative stress via selective elimination of hydroxyl freebase (OH) and peroxynitrite anion (ONOOˉ). Subsequently, there have been numerous experiments on H₂. Most research and trials involving the mechanisms underlying H₂ therapy show the effects of antioxygenation, anti-inflammation, and anti-apoptosis. Among quantities of diseases related with H₂ therapy, the brain disease is a hotspot as brain tissue and cell damage are easier to be induced by oxidative stress and other stimulations. In this review, emphasis is on stroke, traumatic brain injuries, and degenerative diseases, such as Alzheimer's disease and Parkinson's disease. Taking into account the blood-brain barrier, penetrability, possible side effects, and the molecular properties of H₂ within a single comprehensive review should contribute to advancing both clinical and non-clinical research and therapies. A systematic introduction of H₂ therapy with regards to mechanisms and cerebral diseases both in animal and human subjects can make it easier to comprehend H₂ therapy and therefore provide the basis for further clinical strategy.

Molecular hydrogen alleviates motor deficits and muscle degeneration in mdx mice

OBJECTIVE

Duchenne muscular dystrophy (DMD) is a devastating muscle disease caused by a mutation in DMD encoding dystrophin. Oxidative stress accounts for dystrophic muscle pathologies in DMD. We examined the effects of molecular hydrogen in mdx mice, a model animal for DMD.

METHODS

The pregnant mother started to take supersaturated hydrogen water (>5 ppm) ad libitum from E15.5 up to weaning of the offspring. The mdx mice took supersaturated hydrogen water from weaning until age 10 or 24 weeks when they were sacrificed.

RESULTS

Hydrogen water prevented abnormal body mass gain that is commonly observed in mdx mice. Hydrogen improved the spontaneous running distance that was estimated by a counter-equipped running-wheel, and extended the duration on the rota-rod. Plasma creatine kinase activities were decreased by hydrogen at ages 10 and 24 weeks. Hydrogen also decreased the number of central nuclei of muscle fibers at ages 10 and 24 weeks, and immunostaining for nitrotyrosine in gastrocnemius muscle at age 24 weeks. Additionally, hydrogen tended to increase protein expressions of antioxidant glutathione peroxidase 1, as well as anti-apoptotic Bcl-2, in skeletal muscle at age 10 weeks.

DISCUSSION

Although molecular mechanisms of the diverse effects of hydrogen remain to be elucidated, hydrogen potentially improves muscular dystrophy in DMD patients.

Molecular hydrogen regulates gene expression by modifying the free radical chain reaction-dependent generation of oxidized phospholipid mediators

We previously showed that H₂ acts as a novel antioxidant to protect cells against oxidative stress. Subsequently, numerous studies have indicated the potential applications of H₂ in therapeutic and preventive medicine. Moreover, H₂ regulates various signal transduction pathways and the expression of many genes. However, the primary targets of H₂ in the signal transduction pathways are unknown. Here, we attempted to determine how H₂ regulates gene expression. In a pure chemical system, H₂ gas (approximately 1%, v/v) suppressed the autoxidation of linoleic acid that proceeds by a free radical chain reaction, and pure 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine (PAPC), one of the major phospholipids, was autoxidized in the presence or absence of H₂. H₂ modified the chemical production of the autoxidized phospholipid species in the cell-free system. Exposure of cultured cells to the H₂-dependently autoxidized phospholipid species reduced Ca²⁺ signal transduction and mediated the expression of various genes as revealed by comprehensive microarray analysis. In the cultured cells, H₂ suppressed free radical chain reaction-dependent peroxidation and recovered the increased cellular Ca²⁺, resulting in the regulation of Ca²⁺-dependent gene expression. Thus, H₂ might regulate gene expression via the Ca²⁺ signal transduction pathway by modifying the free radical-dependent generation of oxidized phospholipid mediators.

Convenient methods for ingestion of molecular hydrogen: drinking, injection, and inhalation

Molecular hydrogen (H2) is clinically administered; however, in some hospitals, H2 is given to patients without consideration of its safe use. In the present study, we prepared convenient and safe devices for the drinking of super-saturated H2 water, for intravenous drip infusion of H2-rich saline, and for the inhalation of H2 gas. In order to provide useful information for researchers using these devices, the changes in H2 concentration were studied. Our experimental results should contribute to the advance of non-clinical and clinical research in H2 medicine.

Intravenous infusion of H2-saline suppresses oxidative stress and elevates antioxidant potential in Thoroughbred horses after racing exercise

Upon intensive, exhaustive exercise, exercise-induced reactive oxygen species may exceed the antioxidant defence threshold, consequently resulting in muscular damage or late-onset chronic inflammation. Recently, the therapeutic antioxidant and anti-inflammatory effects of molecular hydrogen (H₂) for human rheumatoid arthritis have been demonstrated. However, it is also important to clarify the effects of administrating H₂ in large animals other than humans, as H₂ is thought to reach the target organ by passive diffusion upon delivery from the blood flow, indicating that the distance from the administration point to the target is critical. However, data on the effects of H₂ on oxidative stress in real-life exhaustive exercise in large animals are currently lacking. We here investigated 13 Thoroughbred horses administered intravenous 2-L saline with or without 0.6-ppm H₂ (placebo, N = 6; H₂, N = 7) before participating in a high-intensity simulation race. Intravenous H₂-saline significantly suppressed oxidative stress immediately, 3 h, and 24 h after the race, although the antioxidant capability was not affected throughout the study. The serum creatine kinase, lactate, and uric acid levels were increased in both groups. Taken together, these results indicate that intravenous H₂-saline can significantly and specifically suppress oxidative stress induced after exhaustive racing in Thoroughbred horses.

Beneficial biological effects and the underlying mechanisms of molecular hydrogen - comprehensive review of 321 original articles

Therapeutic effects of molecular hydrogen for a wide range of disease models and human diseases have been investigated since 2007. A total of 321 original articles have been published from 2007 to June 2015. Most studies have been conducted in Japan, China, and the USA. About three-quarters of the articles show the effects in mice and rats. The number of clinical trials is increasing every year. In most diseases, the effect of hydrogen has been reported with hydrogen water or hydrogen gas, which was followed by confirmation of the effect with hydrogen-rich saline. Hydrogen water is mostly given ad libitum. Hydrogen gas of less than 4 % is given by inhalation. The effects have been reported in essentially all organs covering 31 disease categories that can be subdivided into 166 disease models, human diseases, treatment-associated pathologies, and pathophysiological conditions of plants with a predominance of oxidative stress-mediated diseases and inflammatory diseases. Specific extinctions of hydroxyl radical and peroxynitrite were initially presented, but the radical-scavenging effect of hydrogen cannot be held solely accountable for its drastic effects. We and others have shown that the effects can be mediated by modulating activities and expressions of various molecules such as Lyn, ERK, p38, JNK, ASK1, Akt, GTP-Rac1, iNOS, Nox1, NF-κB p65, IκBα, STAT3, NFATc1, c-Fos, and ghrelin. Master regulator(s) that drive these modifications, however, remain to be elucidated and are currently being extensively investigated.