Consumption of hydrogen water prevents atherosclerosis in apolipoprotein E knockout mice

The role of hydrogen in the prevention and treatment of coronary atherosclerotic heart disease

Coronary atherosclerotic heart disease (CHD) is a primary cardiovascular disease caused by atherosclerosis (AS), which is characterized by chronic inflammation and lipid oxidative deposition. Molecular hydrogen (H2) is an effective anti-inflammatory agent and has potential to ameliorate glycolipid metabolism disorders, which is believed to exert beneficial effects on the prevention and treatment of CHD. It is suggested that H2 reduces inflammation in CHD by regulating multiple pathways, including NF-κB inflammatory pathway, pyroptosis, mitophagy, endoplasmic reticulum (ER) stress, and Nrf2 antioxidant pathway. Additionally, H2 may improve glycolipid metabolism by mediation of PI3K and AMPK signalling pathways, contributing to inhibition of the occurrence and development of CHD. This review elaborates pathogenesis of CHD and evaluates the role of H2 in CHD. Moreover, possible molecular mechanisms have been discussed and speculated, aiming to provide more strategies and directions for subsequent studies of H2 in CHD.

Pyroptosis in myocardial ischemia/reperfusion and its therapeutic implications

Ischemic heart disease, a prevalent cardiovascular disease with global significance, is associated with substantial morbidity. Timely and successful reperfusion is crucial for reducing infarct size and enhancing clinical outcomes. However, reperfusion may induce additional myocardium injury, manifesting as myocardial ischemia/reperfusion (MI/R) injury. Pyroptosis is a regulated cell death pathway, the signaling pathway of which is activated during MI/R injury. In this process, the inflammasomes are triggered, initiating the cleavage of gasdermin proteins and pro-interleukins, which results in the formation of membrane pores and the maturation and secretion of inflammatory cytokines. Numerous preclinical evidence underscores the pivotal role of pyroptosis in MI/R injury. Inhibiting pyroptosis is cardioprotective against MI/R injury. Although certain agents exhibiting promise in preclinical studies for attenuating MI/R injury through inhibiting pyroptosis have been identified, the suitability of these compounds for clinical trials remains untested. This review comprehensively summarizes the recent developments in this field, with a specific emphasis on the impact of pyroptosis on MI/R injury. Deciphering these findings not only sheds light on new disease mechanisms but also paves the way for innovative treatments. And then the exploration of the latest advances in compounds that inhibit pyroptosis in MI/R is discussed, which aims to provide insights into potential therapeutic strategies and identify avenues for future research in the pursuit of effective clinical interventions.

Recent Advances in Metal-Hydride-Based Disease Treatment

In comparison to traditional antioxidant treatment methods, the use of hydrogen to eliminate reactive oxygen species from the body has the advantages of high biological safety, strong selectivity, and high clearance rate. As an energy storage material, metal hydrides have been extensively studied and used in transporting hydrogen as clean energy, which can achieve a high hydrogen load and controlled hydrogen release. Considering the antioxidant properties of hydrogen and the delivery ability of metal hydrides, metal-hydride-based disease treatment strategies have attracted widespread attention. Up to now, metal hydrides have been reported for the treatment of tumors and a range of inflammation-related diseases. However, limited by the insufficient investment, the use of metal hydrides in disease treatment still has many shortcomings, such as low targeting efficiency, limited therapeutic activity, and complex material preparation process. Particularly, metal hydrides have been found to have a series of optical, acoustic, and catalytic properties when scaled up to the nanoscale, and these properties are also widely used to promote disease treatment effects. From this new perspective, we comprehensively summarize the very recent research progress on metal-hydride-based disease treatment in this review. Ultimately, the challenges and prospects of such a burgeoning cancer theranostics modality are outlooked to provide inspiration for the further development and clinical translation of metal hydrides.

Hydrogen Attenuates Chronic Intermittent Hypoxia-Induced Cardiac Hypertrophy by Regulating Iron Metabolism

The present study aimed to investigate the impact of hydrogen (H2) on chronic intermittent hypoxia (CIH)-induced cardiac hypertrophy in mice by modulating iron metabolism. C57BL/6N mice were randomly allocated into four groups: control (Con), CIH, CIH + H2, and H2. The mice were exposed to CIH (21-5% FiO2, 3 min/cycle, 8 h/d), and received inhalation of a hydrogen-oxygen mixture (2 h/d) for 5 weeks. Cardiac and mitochondrial function, levels of reactive oxygen species (ROS), and iron levels were evaluated. The H9C2 cell line was subjected to intermittent hypoxia (IH) and treated with H2. Firstly, we found H2 had a notable impact on cardiac hypertrophy, ameliorated pathological alterations and mitochondrial morphology induced by CIH (p < 0.05). Secondly, H2 exhibited a suppressive effect on oxidative injury by decreasing levels of inducible nitric oxide synthase (i-NOS) (p < 0.05) and 4-hydroxynonenal (4-HNE) (p < 0.01). Thirdly, H2 demonstrated a significant reduction in iron levels within myocardial cells through the upregulation of ferroportin 1 (FPN1) proteins (p < 0.01) and the downregulation of transferrin receptor 1 (TfR1), divalent metal transporter 1 with iron-responsive element (DMT1(+ire)), and ferritin light chain (FTL) mRNA or proteins (p < 0.05). Simultaneously, H2 exhibited the ability to decrease the levels of Fe2+ and ROS in H9C2 cells exposed to IH (p < 0.05). Moreover, H2 mediated the expression of hepcidin, hypoxia-inducible factor-1α (HIF-1α) (p < 0.01), and iron regulatory proteins (IRPs), which might be involved in the regulation of iron-related transporter proteins. These results suggested that H2 may be beneficial in preventing cardiac hypertrophy, a condition associated with reduced iron toxicity.

Clinical Use and Treatment Mechanism of Molecular Hydrogen in the Treatment of Various Kidney Diseases including Diabetic Kidney Disease

As diabetes rates surge globally, there is a corresponding rise in the number of patients suffering from diabetic kidney disease (DKD), a common complication of diabetes. DKD is a significant contributor to chronic kidney disease, often leading to end-stage renal failure. However, the effectiveness of current medical treatments for DKD leaves much to be desired. Molecular hydrogen (H2) is an antioxidant that selectively reduces hydroxyl radicals, a reactive oxygen species with a very potent oxidative capacity. Recent studies have demonstrated that H2 not only possesses antioxidant properties but also exhibits anti-inflammatory effects, regulates cell lethality, and modulates signal transduction. Consequently, it is now being utilized in clinical applications. Many factors contribute to the onset and progression of DKD, with mitochondrial dysfunction, oxidative stress, and inflammation being strongly implicated. Recent preclinical and clinical trials reported that substances with antioxidant properties may slow the progression of DKD. Hence, we undertook a comprehensive review of the literature focusing on animal models and human clinical trials where H2 demonstrated effectiveness against a variety of renal diseases. The collective evidence from this literature review, along with our previous findings, suggests that H2 may have therapeutic benefits for patients with DKD by enhancing mitochondrial function. To substantiate these findings, future large-scale clinical studies are needed.

Hydrogen therapy as a potential therapeutic intervention in heart disease: from the past evidence to future application

Cardiovascular disease is the leading cause of mortality worldwide. Excessive oxidative stress and inflammation play an important role in the development and progression of cardiovascular disease. Molecular hydrogen, a small colorless and odorless molecule, is considered harmless in daily life when its concentration is below 4% at room temperature. Owing to the small size of the hydrogen molecule, it can easily penetrate the cell membrane and can be metabolized without residue. Molecular hydrogen can be administered through inhalation, the drinking of hydrogen-rich water, injection with hydrogen-rich-saline, and bathing of an organ in a preservative solution. The utilization of molecular hydrogen has shown many benefits and can be effective for a wide range of purposes, from prevention to the treatment of diseases. It has been demonstrated that molecular hydrogen exerts antioxidant, anti-inflammatory, and antiapoptotic effects, leading to cardioprotective benefits. Nevertheless, the exact intracellular mechanisms of its action are still unclear. In this review, evidence of the potential benefits of hydrogen molecules obtained from in vitro, in vivo, and clinical investigations are comprehensively summarized and discussed with a focus on the cardiovascular aspects. The potential mechanisms involved in the protective effects of molecular hydrogen are also presented. These findings suggest that molecular hydrogen could be used as a novel treatment in various cardiovascular pathologies, including ischemic-reperfusion injury, cardiac injury from radiation, atherosclerosis, chemotherapy-induced cardiotoxicity, and cardiac hypertrophy.

Redox-Mechanisms of Molecular Hydrogen Promote Healthful Longevity

Age-related diseases represent the largest threat to public health. Aging is a degenerative, systemic, multifactorial and progressive process, coupled with progressive loss of function and eventually leading to high mortality rates. Excessive levels of both pro- and anti-oxidant species qualify as oxidative stress (OS) and result in damage to molecules and cells. OS plays a crucial role in the development of age-related diseases. In fact, damage due to oxidation depends strongly on the inherited or acquired defects of the redox-mediated enzymes. Molecular hydrogen (H2) has recently been reported to function as an anti-oxidant and anti-inflammatory agent for the treatment of several oxidative stress and aging-related diseases, including Alzheimer's, Parkinson's, cancer and osteoporosis. Additionally, H2 promotes healthy aging, increases the number of good germs in the intestine that produce more intestinal hydrogen and reduces oxidative stress through its anti-oxidant and anti-inflammatory activities. This review focuses on the therapeutic role of H2 in the treatment of neurological diseases. This review manuscript would be useful in knowing the role of H2 in the redox mechanisms for promoting healthful longevity.

Hydrogen inhalation enhances autophagy via the AMPK/mTOR pathway, thereby attenuating doxorubicin-induced cardiac injury

AIMS

Doxorubicin is a drug widely used in clinical cancer treatment, but severe cardiotoxicity limits its clinical application. Autophagy disorder is an important factor in the mechanism of doxorubicin-induced cardiac injury. As the smallest molecule in nature, hydrogen has various biological effects such as anti-oxidation, anti-apoptosis and regulation of autophagy. Hydrogen therapy is currently considered to be an emerging therapeutic method, but the effect and mechanism of hydrogen on doxorubicin-induced myocardial injury have not been determined. The purpose of this study was to investigate the protective effect of hydrogen inhalation on doxorubicin-induced chronic myocardial injury and its effect and mechanism on autophagy.

METHODS

In this study, we established a chronic heart injury model by intraperitoneal injection of doxorubicin in rats for 30 days, accumulating 20 mg/kg. The effect of hydrogen inhalation on the cardiac function in rats was explored by echocardiography, Elisa, and H&E staining. To clarify the influence of autophagy, we detected the expression of LC3 and related autophagy proteins in vivo and in vitro by immunofluorescence and western blot.In order to further explore the mechanism of autophagy, we added pathway inhibitors and used western blot to preliminarily investigate the protective effect of hydrogen inhalation on myocardial injury caused by doxorubicin.

RESULTS

Hydrogen inhalation can improve doxorubicin-induced cardiac function decline and pathological structural abnormalities in rats. It was confirmed by immunofluorescence that hydrogen treatment could restore the expression of autophagy marker protein LC3 (microtubule-associated protein 1 light chain 3) in cardiomyocytes reduced by doxorubicin, while reducing cardiomyocyte apoptosis. Mechanistically, Western blot results consistently showed that hydrogen treatment up-regulated the ratio of p-AMPK (phosphorylated AMP-dependent protein kinase) to AMPK and down-regulated p-mTOR (phosphorylated mammalian target of rapamycin) and mTOR ratio.

CONCLUSIONS

These results suggest that hydrogen inhalation can activate autophagy through the AMPK/mTOR pathway and protect against myocardial injury induced by doxorubicin. Hydrogen inhalation therapy may be a potential treatment for doxorubicin-induced myocardial injury.

Therapeutic Potential of Molecular Hydrogen in Metabolic Diseases from Bench to Bedside

Oxidative stress and chronic inflammation have been implicated in the pathophysiology of metabolic diseases, including diabetes mellitus (DM), metabolic syndrome (MS), fatty liver (FL), atherosclerosis (AS), and obesity. Molecular hydrogen (H₂) has long been considered a physiologically inert gas. In the last two decades, accumulating evidence from pre-clinical and clinical studies has indicated that H₂ may act as an antioxidant to exert therapeutic and preventive effects on various disorders, including metabolic diseases. However, the mechanisms underlying the action of H₂ remain unclear. The purpose of this review was to (1) provide an overview of the current research on the potential effects of H₂ on metabolic diseases; (2) discuss the possible mechanisms underlying these effects, including the canonical anti-oxidative, anti-inflammatory, and anti-apoptotic effects, as well as suppression of ER stress, activation of autophagy, improvement of mitochondrial function, regulation of gut microbiota, and other possible mechanisms. The potential target molecules of H₂ will also be discussed. With more high-quality clinical trials and in-depth mechanism research, it is believed that H₂ will eventually be applied to clinical practice in the future, to benefit more patients with metabolic disease.

Taurine, Coenzyme Q10, and Hydrogen Water Prevents Germanium Dioxide-Induced Mitochondrial Dysfunction and Associated Sensorineural Hearing Loss in mouse

Mitochondrial dysfunction has been implicated in numerous common diseases as well as aging and plays an important role in the pathogenesis of sensorineural hearing loss (SNHL). In the current study, we showed that supplementation with germanium dioxide (GeO₂) in CBA/J mice resulted in SNHL due to the degeneration of the stria vascularis and spiral ganglion, which were associated with down-regulation of mitochondrial respiratory chain associated genes and up-regulation in apoptosis associated genes in the cochlea. Supplementation with taurine, coenzyme Q10, or hydrogen-rich water, attenuated the cochlear degeneration and associated SNHL induced by GeO₂. These results suggest that daily supplements or consumption of antioxidants, such as taurine, coenzyme Q10, and hydrogen-rich water, may be a promising intervention to slow SNHL associated with mitochondrial dysfunction.

Research Progress on the Role of Pyroptosis in Myocardial Ischemia-Reperfusion Injury

Myocardial ischemia-reperfusion injury (MIRI) results in the aggravation of myocardial injury caused by rapid recanalization of the ischemic myocardium. In the past few years, there is a growing interest in investigating the complex pathophysiological mechanism of MIRI for the identification of effective targets and drugs to alleviate MIRI. Currently, pyroptosis, a type of inflammatory programmed death, has received greater attention. It is involved in the MIRI development in combination with other mechanisms of MIRI, such as oxidative stress, calcium overload, necroptosis, and apoptosis, thereby forming an intertwined association between different pathways that affect MIRI by regulating common pathway molecules. This review describes the pyroptosis mechanism in MIRI and its relationship with other mechanisms, and also highlights non-coding RNAs and non-cardiomyocytes as regulators of cardiomyocyte pyroptosis by mediating associated pathways or proteins to participate in the initiation and development of MIRI. The research progress on novel small molecule drugs, clinical drugs, traditional Chinese medicine, etc. for regulating pyroptosis can play a crucial role in effective MIRI alleviation. When compared to research on other mature mechanisms, the research studies on pyroptosis in MIRI are inadequate. Although many related protective drugs have been identified, these drugs generally lack clinical applications. It is necessary to further explore and verify these drugs to expand their applications in clinical setting. Early inhibition of MIRI by targeted regulation of pyroptosis is a key concern that needs to be addressed in future studies.

Effect of Hydrogen Inhalation Therapy on Hearing Loss of Patients With Nasopharyngeal Carcinoma After Radiotherapy

Objective

To evaluate the clinical efficacy and safety of hydrogen inhalation in improving hearing loss in patients with long-term survival of nasopharyngeal carcinoma after radiotherapy.

Methods

The eustachian tube dysfunction score, pure tone air conduction threshold, bone conduction threshold, the score of tympanogram and otoscope were prospectively observed in patients with deafness after radiotherapy only or combined radiotherapy and chemotherapy for nasopharyngeal carcinoma. Paired t test and one-way analysis of variance were used to analyze the data before and after treatment.

Results

A total of 17 patients were observed. The median time from radiotherapy to now was 228 months, and the median time from the diagnose of deafness to now was 92 months. After 4 weeks of hydrogen inhalation, the score of eustachian tube dysfunction, air conduction and bone conduction hearing thresholds were significantly reduced, P values were 0.0293, 0.0027, 0.0404, respectively. The mean air-bone gap, the score of otoendoscopy and tympanogram were also decreased, but the differences were not significant (P = 0.2079, P = 0.0536, P = 0.1056). Patients with radiotherapy alone and concurrent chemo-radiotherapy had significantly lower air conduction hearing threshold after hydrogen absorption (P = 0.0142, P = 0.0495). The results of air and bone hearing thresholds before, 4 and 12 weeks after hydrogen inhalation showed a descending trend. The air and bone hearing thresholds before hydrogen inhalation were 74.69 ± 27.03 dB and 45.70 ± 21.58 dB, respectively. At the 12th week, the mean values of air and bone hearing thresholds were the lowest, which were 66.88 ± 20.88 dB and 40.94 ± 18.93 dB, respectively, but there was no significant difference in air and bone hearing thresholds among all groups (P = 0.6755, P = 0.7712). After hydrogen inhalation treatment, no adverse reactions such as nosebleed, chest pain, dyspnea, nausea, vomiting, dizziness, earache and allergic reaction were observed.

Conclusion

This is the first prospective study on the effect of hydrogen inhalation on hearing improvement in patients with deafness after radiotherapy/chemotherapy for nasopharyngeal carcinoma, suggesting that continuous hydrogen inhalation may be an alternative rehabilitation therapy for these patients.

Role of Molecular Hydrogen in Ageing and Ageing-Related Diseases

Ageing is a physiological process of progressive decline in the organism function over time. It affects every organ in the body and is a significant risk for chronic diseases. Molecular hydrogen has therapeutic and preventive effects on various organs. It has antioxidative properties as it directly neutralizes hydroxyl radicals and reduces peroxynitrite level. It also activates Nrf2 and HO-1, which regulate many antioxidant enzymes and proteasomes. Through its antioxidative effect, hydrogen maintains genomic stability, mitigates cellular senescence, and takes part in histone modification, telomere maintenance, and proteostasis. In addition, hydrogen may prevent inflammation and regulate the nutrient-sensing mTOR system, autophagy, apoptosis, and mitochondria, which are all factors related to ageing. Hydrogen can also be used for prevention and treatment of various ageing-related diseases, such as neurodegenerative disorders, cardiovascular disease, pulmonary disease, diabetes, and cancer. This paper reviews the basic research and recent application of hydrogen in order to support hydrogen use in medicine for ageing prevention and ageing-related disease therapy.

Effects of hydrogen-rich water and ascorbic acid treatment on spontaneously hypertensive rats

Hydrogen-rich water (HW) has been suggested to possess antioxidant properties of value in treatments of lifestyle diseases and for prevention of latent pathologies. To date, the potential benefits of HW against the deleterious effects of excessive salt intake and hypertension have not been investigated. Here, we first examined the effects of HW or HW supplemented with 0.1% ascorbic acid (HWA) on spontaneously hypertensive rats (SHR) that had been fed a normal diet. In comparison to control rats given distilled water (DW), we found that HW did not significantly influence systolic blood pressure (SBP) or diastolic blood pressure (DBP) in SHR; however, the increase in SBP and DBP were inhibited in the HWA group. Next, four groups of SHR were given DW, 0.1% ascorbic acid-added DW (DWA), HW, or HWA in combination with a 4% NaCl-added diet. SHR fed the 4% NaCl-added diet showed increased hypertension; HWA treatment resulted in a significant reduction in blood pressure. The HWA group tended to have lower plasma angiotensin II levels than the DW group. In addition, urinary volumes and urinary sodium levels were significantly lower in the HWA group than the DW group. Urinary isoprostane, an oxidative stress marker, was also significantly lower in the HWA group, suggesting that the inhibitory effect of HWA on blood pressure elevation was caused by a reduction in oxidative stress. These findings suggest a synergistic interaction between HW and ascorbic acid, and also suggest that HWA ingestion has potential for prevention of hypertension.

Role of Hydrogen in Atherosclerotic Disease: From Bench to Bedside

Atherosclerotic cardiovascular and cerebrovascular diseases are among the leading causes of morbidity and mortality worldwide. Given our recent understanding of its role as a small-molecule antioxidant and anti- inflammatory agent, hydrogen may play an important role in preventing and treating atherosclerotic cardiovascular and cerebrovascular disease. In the past decade, more than 50 publications in the English language literature considered the role of hydrogen as an anti-atherosclerotic agent. In this review, we summarized the pathophysiological characteristics and risk factors associated with atherosclerosis (AS) and the laboratory research data that focuses on hydrogen to prevent and treat this condition, including the responses observed in both animal models and human studies. We will also consider the molecular mechanisms underlying the efficacy of hydrogen molecules with respect to atherosclerotic disease. Future studies might include clinical trials with larger sample populations as well as experiments designed to explore the molecular mechanisms associated with hydrogen treatment in greater depth.

Biological Responses to Hydrogen Molecule and its Preventive Effects on Inflammatory Diseases

Because multicellular organisms do not have hydrogenase, H₂ has been considered to be biologically inactive in these species, and enterobacteria to be largely responsible for the oxidation of H₂ taken into the body. However, we showed previously that inhalation of H₂ markedly suppresses brain injury induced by focal ischemia-reperfusion by buffering oxidative stress. Although the reaction constant of H₂ with hydroxyl radical in aqueous solution is two to three orders of magnitude lower than that of conventional antioxidants, we showed that hydroxyl radical generated by the Fenton reaction reacts with H₂ at room temperature without a catalyst. Suppression of hydroxyl radical by H₂ has been applied in ophthalmic surgery. However, many of the anti- inflammatory and other therapeutic effects of H₂ cannot be completely explained by its ability to scavenge reactive oxygen species. H₂ administration is protective in several disease models, and preculture in the presence of H₂ suppresses oxidative stress-induced cell death. Specifically, H₂ administration induces mitochondrial oxidative stress and activates Nrf2; this phenomenon, in which mild mitochondrial stress leaves the cell less susceptible to subsequent perturbations, is called mitohormesis. Based on these findings, we conclude that crosstalk between antioxidative stress pathways and the anti-inflammatory response is the most important molecular mechanism involved in the protective function of H₂, and that regulation of the immune system underlies H₂ efficacy. For further medical applications of H₂, it will be necessary to identify the biomolecule on which H₂ first acts.

Hydrogen gas inhalation alleviates myocardial ischemia-reperfusion injury by the inhibition of oxidative stress and NLRP3-mediated pyroptosis in rats

AIMS

Reperfusion therapy is the most common and effective treatment against ischemic heart disease (IHD), but the process inflicts massive ischemia/reperfusion (I/R) injury for which no treatment exists. Notably, reperfusion after ischemia causes ischemia/reperfusion injury (IR injury) and the "no-reflow" phenomenon seriously affecting the therapeutic effects in clinical practice. The principle purpose of this study is to validate the effect of hydrogen gas on IHD and further explore the mechanism of hydrogen gas in alleviating myocardial I/R injury and no-reflow phenomenon.

MATERIALS AND METHODS

The rat model of myocardial ischemia-reperfusion was well established. Myocardial infarct size was evaluated by TTC & Evans blue staining. The no-reflow area and the cardiac function were assessed by thioflavin-S staining and echocardiography respectively. Microstructure and mitochondria of myocardial tissue were assessed by transmission electron microscope. Western blot and immunohistochemistry were used to evaluate the expression of NLRP3 mediated pyroptosis related proteins. The 8-OHdG, MDA and serum total ROS were used to evaluate the degree of oxidative stress.

KEY FINDINGS

The myocardial infarct size, no-reflow area, cardiac function, microstructure and mitochondrial morphology of I/R model rats were significantly improved after hydrogen inhalation. In addition, the expression of 8-OHdG, MDA, ROS and NLRP3 mediated pyroptosis related proteins were significantly decreased.

SIGNIFICANCE

We found that oxidative stress and NLRP3 mediated pyroptosis are the important mechanisms for hydrogen to alleviate myocardial I/R injury, and we also confirmed that hydrogen can significantly improve no reflow phenomenon caused by ischemia-reperfusion.

Redox Effects of Molecular Hydrogen and Its Therapeutic Efficacy in the Treatment of Neurodegenerative Diseases

Oxidative stress (OS) and neuroinflammatory stress affect many neurological disorders. Despite the clinical significance of oxidative damage in neurological disorders, still, no effective and safe treatment methods for neuro diseases are available. With this, molecular hydrogen (H2) has been recently reported as an antioxidant and anti-inflammatory agent to treat several oxidative stress-related diseases. In animal and human clinical trials, the routes for H2 administration are mainly categorized into three types: H2 gas inhalation, H2 water dissolving, and H2-dissolved saline injection. This review explores some significant progress in research on H2 use in neurodegenerative diseases (NDs), including Alzheimer’s disease, Parkinson’s disease, neonatal disorders of the brain, and other NDs (retinal ischemia and traumatic brain injury). Even though most neurological problems are not currently curable, these studies have shown the therapeutic potential for prevention, treatment, and mitigation of H2 administration. Several possible H2-effectors, including cell signaling molecules and hormones, which prevent OS and inflammation, will also be addressed. However, more clinical and other related studies are required to evaluate the direct H2 target molecule.

A narrative review of hydrogen-oxygen mixture for medical purpose and the inhaler thereof

Recent development regarding mixture of H₂ (concentration of ~66%) with O₂ (concentration of ~34%) for medical purpose, such as treatment of coronavirus disease-19 (COVID-19) patients, is introduced. Furthermore, the design principles of a hydrogen inhaler which generates mixture of hydrogen (~66%) with oxygen (~34%) for medical purpose are proposed. With the installation of the liquid blocking module and flame arresters, the air pathway of the hydrogen inhaler is divided by multiple isolation zones to prevent any unexpected explosion propagating from one zone to the other. An integrated filtering/cycling module is utilized to purify the impurity, and cool down the temperature of the electrolytic module to reduce the risk of the explosion. Moreover, a nebulizer is provided to selectively atomize the water into vapor which is then mixed with the filtered hydrogen-oxygen mix gas, such that the static electricity of a substance hardly occurs to reduce the risk of the explosion. Furthermore, hydrogen concentration detector is installed to reduce the risk of hydrogen leakage. Result shows that the hydrogen inhaler implementing the aforesaid design rules could effectively inhibit the explosion, even ignition at the outset of the hydrogen inhaler which outputs hydrogen-oxygen gas (approximately 66% hydrogen: 34% oxygen).

Hydrogen: A Novel Option in Human Disease Treatment

H₂ has shown anti-inflammatory and antioxidant ability in many clinical trials, and its application is recommended in the latest Chinese novel coronavirus pneumonia (NCP) treatment guidelines. Clinical experiments have revealed the surprising finding that H₂ gas may protect the lungs and extrapulmonary organs from pathological stimuli in NCP patients. The potential mechanisms underlying the action of H₂ gas are not clear. H₂ gas may regulate the anti-inflammatory and antioxidant activity, mitochondrial energy metabolism, endoplasmic reticulum stress, the immune system, and cell death (apoptosis, autophagy, pyroptosis, ferroptosis, and circadian clock, among others) and has therapeutic potential for many systemic diseases. This paper reviews the basic research and the latest clinical applications of H₂ gas in multiorgan system diseases to establish strategies for the clinical treatment for various diseases.

Eating right for a healthier heart: Food choice contributes to cardiometabolic benefits and reduction of carotid intima-media thickness

OBJECTIVES

Diets may alter an individual's metabolism and inflammation, collectively leading to the modulation of cardiovascular health and disease process. The aim of this study was to investigate the effects of diets and diet-associated metabolites on metabolic profiles, inflammatory status, and severity of atherosclerosis.

METHODS

A cross-sectional study was conducted with 81 healthy adults in Taiwan. A food frequency questionnaire was obtained for evaluating dietary intake. Carotid intima-media thickness (CIMT), a relevant marker of subclinical atherosclerosis, was measured by ultrasound.

RESULTS

Consumption of instant noodles and sugary beverages was associated with worse metabolic profiles. In contrast, the intake of fresh fruit and green vegetables was correlated with better metabolic parameters. Sugary beverages were dose-dependently correlated with higher expressions of toll-like receptor (TLR)2 and TLR4 on monocytes, whereas fresh fruit intake was associated with lower TLRs. Furthermore, consumption of green vegetables, brown rice, and >2000 mL/d of water was inversely correlated with CIMT. The diet-associated metabolites including trimethylamine N-oxide and S-adenosyl-l-homocysteine, were positively associated with CIMT, whereas l-lysine and l-carnitine were associated with decreased CIMT. Interestingly, intake of strict vegetarian foods resulted in lower serum total cholesterol levels without a detectable effect on inflammatory status or CIMT.

CONCLUSIONS

Independent of the pattern of strict vegetarian foods, individuals who consumed more vegetables, fresh fruit, and water showed better cardiovascular health as evidenced by their metabolic and inflammatory status and CIMT results.

Hydrogen gas protects against ovariectomy-induced osteoporosis by inhibiting NF-κB activation

OBJECTIVES

Osteoporosis is a prevalent condition among postmenopausal women, and lacks satisfactory therapeutic options. Hydrogen (H2) has been shown to be effective in alleviating many diseases. This study aimed to investigate the effects of H2 on inhibiting osteoclastogenesis and bone loss in ovariectomized mice.

METHODS

Osteoclast differentiation from Raw264.7 cells was induced with receptor activator NF-κB ligand (RANKL) with or without 60% H2. The number and resorption activity of osteocalsts were assessed by tartrate-resistant acid phosphatase staining and pit formation assay, respectively. The expression of osteoclast markers and NF-κB phosphorylation were detected by western blot. NF-κB nuclear translocation was assessed by immunofluorescence. NF-κB transcriptional activity was analyzed by luciferase assay. Bone loss in mice was induced by ovariectomy (OVX). OVX mice were given either regular air or 60% H2. Bone structure was analyzed by micro-computed tomography and hematoxylin and eosin staining. Cytokine levels were measured by enzyme-linked immunosorbent assay. The data were analyzed with one-way or two-way ANOVA followed by Bonferroni post hoc tests.

RESULTS

H2 did not have any measurable effect on the proliferation of Raw264.7 cells. The number of osteoclasts and size of resorption pits of RANKL+H2-treated cells were 3 to 4 times less than RANKL treated cells. The expression of osteoclast marker genes of RANKL+H2-treated cells was 30% to 60% lower than RANKL-treated cells (P < 0.05). H2 markedly inhibited RANKL-induced activation, nuclear translocation, and transcriptional activity of NF-κB (P < 0.05, RANKL+H2 vs RANKL). The amount and density of trabecular bone and bone mineral density of ovariectomized mice were significantly less than sham-operated mice (P < 0.05 OVX vs sham). The amount of trabecular bone and bone mineral density of OVX mice that inhaled H2 were more than 40% higher, whereas the levels of serum proinflammatory cytokine interleukin 1β, IL-6, and tumor necrosis factor-α were more than 50% lower than those of OVX mice (P < 0.05).

CONCLUSIONS

These results demonstrated that H2 could be an effective therapeutic agent of postmenopausal osteoporosis.

Hydrogen Attenuates Allergic Inflammation by Reversing Energy Metabolic Pathway Switch

Mechanisms mediating the protective effects of molecular hydrogen (H₂) are not well understood. This study explored the possibility that H₂ exerts its anti-inflammatory effect by modulating energy metabolic pathway switch. Activities of glycolytic and mitochondrial oxidative phosphorylation systems were assessed in asthmatic patients and in mouse model of allergic airway inflammation. The effects of hydrogen treatment on airway inflammation and on changes in activities of these two pathways were evaluated. Monocytes from asthmatic patients and lungs from ovalbumin-sensitized and challenged mice had increased lactate production and glycolytic enzyme activities (enhanced glycolysis), accompanied by decreased ATP production and mitochondrial respiratory chain complex I and III activities (suppressed mitochondrial oxidative phosphorylation), indicating an energy metabolic pathway switch. Treatment of ovalbumin-sensitized and challenged mice with hydrogen reversed the energy metabolic pathway switch, and mitigated airway inflammation. Hydrogen abrogated ovalbumin sensitization and challenge-induced upregulation of glycolytic enzymes and hypoxia-inducible factor-1α, and downregulation of mitochondrial respiratory chain complexes and peroxisome proliferator activated receptor-γ coactivator-1α. Hydrogen abrogated ovalbumin sensitization and challenge-induced sirtuins 1, 3, 5 and 6 downregulation. Our data demonstrates that allergic airway inflammation is associated with an energy metabolic pathway switch from oxidative phosphorylation to aerobic glycolysis. Hydrogen inhibits airway inflammation by reversing this switch. Hydrogen regulates energy metabolic reprogramming by acting at multiple levels in the energy metabolism regulation pathways.

The Effects of 24-Week, High-Concentration Hydrogen-Rich Water on Body Composition, Blood Lipid Profiles and Inflammation Biomarkers in Men and Women with Metabolic Syndrome: A Randomized Controlled Trial

PURPOSE

Metabolic syndrome is associated with several medical risk factors including dyslipidemia, hyperglycemia, and obesity, which has become a worldwide pandemic. The sequelae of this condition increase the risk of cardiovascular and neurological disease and increased mortality. Its pathophysiology is associated with redox dysregulation, excessive inflammation, and perturbation of cellular homeostasis. Molecular hydrogen (H₂) may attenuate oxidative stress, improve cellular function, and reduce chronic inflammation. Pre-clinical and clinical studies have shown promising effects of H₂-rich water (HRW) on specific features of metabolic syndrome, yet the effects of long-term, high-concentration HRW in this prevalent condition remain poorly addressed.

METHODS

We conducted a randomized, double-blinded, placebo-controlled trial in 60 subjects (30 men and 30 women) with metabolic syndrome. An initial observation period of one week was used to acquire baseline clinical data followed by randomization to either placebo or high-concentration HRW (> 5.5 millimoles of H₂ per day) for 24 weeks.

RESULTS

Supplementation with high-concentration HRW significantly reduced blood cholesterol and glucose levels, attenuated serum hemoglobin A1c, and improved biomarkers of inflammation and redox homeostasis as compared to placebo (P < 0.05). Furthermore, H₂ tended to promote a mild reduction in body mass index and waist-to-hip ratio.

CONCLUSION

Our results give further credence that high-concentration HRW might have promising effects as a therapeutic modality for attenuating risk factors of metabolic syndrome.

Protective Role of Hydrogen Gas on Oxidative Damage and Apoptosis in Intestinal Porcine Epithelial Cells (IPEC-J2) Induced by Deoxynivalenol: A Preliminary Study

To explore the protective role of hydrogen gas (H2) on oxidative damage and apoptosis in intestinal porcine epithelial cells (IPEC-J2) induced by deoxynivalenol (DON), cells were assigned to four treatment groups, including control, 5 μM DON, H2-saturated medium, and 5 μM DON + H2-saturated medium treatments. After 12 h of different treatments, the cell viability, biomarkers of cell redox states, and gene expression of antioxidant enzymes and apoptosis were observed and detected. Furthermore, caspase-3 and Bax protein expressions were measured by Western blot analysis. Our results demonstrated that the 5 μM DON significantly caused cytotoxicity to IPEC-J2 cells by reducing cell viability and increasing lactate dehydrogenase release in culture supernatants. Moreover, DON treatments significantly increased levels of 8-hydroxy-2'-deoxyguanosine, 3-nitrotyrosine, and malonaldehyde; however, they decreased total superoxide dismutase and catalase activities and downregulated messenger RNA (mRNA) expression related to antioxidant enzymes in cells. The 5 μM DON treatment also downregulated Bcl-2 expression and upregulated caspase-3 and Bax expression. However, the H2-saturated medium significantly improved cell growth status and reversed the change of redox states and expression of genes and proteins related to apoptosis induced by DON in IPEC-J2 cells. In conclusion, H2 could protect IPEC-J2 cells from DON-induced oxidative damage and apoptosis in vitro.

Molecular Hydrogen Prevents Social Deficits and Depression-Like Behaviors Induced by Low-Intensity Blast in Mice

Detonation of explosive devices creates blast waves, which can injure brains even in the absence of external injuries. Among these, blast-induced mild traumatic brain injury (bmTBI) is increasing in military populations, such as in the wars in Afghanistan, Iraq, and Syria. Although the clinical presentation of bmTBI is not precisely defined, it is frequently associated with psycho-neurological deficits and usually manifests in the form of poly-trauma including psychiatric morbidity and cognitive disruption. Although the underlying mechanisms of bmTBI are largely unknown, some studies suggested that bmTBI is associated with blood-brain barrier disruption, oxidative stress, and edema in the brain. The present study investigated the effects of novel antioxidant, molecular hydrogen gas, on bmTBI using a laboratory-scale shock tube model in mice. Hydrogen gas has a strong prospect for clinical use due to easy preparation, low-cost, and no side effects. The administration of hydrogen gas significantly attenuated the behavioral deficits observed in our bmTBI model, suggesting that hydrogen application might be a strong therapeutic method for treatment of bmTBI.

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.

Molecular hydrogen suppresses free-radical-induced cell death by mitigating fatty acid peroxidation and mitochondrial dysfunction

Molecular hydrogen (H₂) was believed to be an inert and nonfunctional molecule in mammalian cells; however, we overturned the concept by reporting the therapeutic effects of H₂ against oxidative stress. Subsequently, extensive studies revealed multiple functions of H₂ by exhibiting the efficacies of H₂ in various animal models and clinical studies. Here, we investigated the effect of H₂ on free-radical-induced cytotoxicity using tert-butyl hydroperoxide in a human acute monocytic leukemia cell line, THP-1. Cell membrane permeability was determined using lactate dehydrogenase release assay and Hoechst 33342 and propidium iodide staining. Fatty acid peroxidation and mitochondrial viability were measured using 2 kinds of fluorescent dyes, Liperfluo and C11-BODIPY, and using the alamarBlue assay based on the reduction of resazurin to resorufin by mainly mitochondrial succinate dehydrogenase, respectively. Mitochondrial membrane potential was evaluated using tetramethylrhodamine methyl ester. As a result, H₂ protected the cultured cells against the cytotoxic effects induced by tert-butyl hydroperoxide; H₂ suppressed cellular fatty acid peroxidation and cell membrane permeability, mitigated the decline in mitochondrial oxidoreductase activity and mitochondrial membrane potential, and protected cells against cell death evaluated using propidium iodide staining. These results suggested that H₂ suppresses free-radical-induced cell death through protection against fatty acid peroxidation and mitochondrial dysfunction.

Molecular hydrogen attenuates gefitinib-induced exacerbation of naphthalene-evoked acute lung injury through a reduction in oxidative stress and inflammation

Although inhibition of epidermal growth factor receptor (EGFR)-mediated cell signaling by the EGFR tyrosine kinase inhibitor gefitinib is highly effective against advanced non-small cell lung cancer, this drug might promote severe acute interstitial pneumonia. We previously reported that molecular hydrogen (H₂) acts as a therapeutic and preventive anti-oxidant. Here, we show that treatment with H₂ effectively protects the lungs of mice from severe damage caused by oral administration of gefitinib after intraperitoneal injection of naphthalene, the toxicity of which is related to oxidative stress. Drinking H₂-rich water ad libitum mitigated naphthalene/gefitinib-induced weight loss and significantly improved survival, which was associated with a decrease in lung inflammation and inflammatory cytokines in the bronchoalveolar lavage fluid. Naphthalene decreased glutathione in the lung, increased malondialdehyde in the plasma, and increased 4-hydroxy-2-nonenal production in airway cells, all of which were mitigated by H₂-rich water, indicating that the H₂-rich water reverses cellular damage to the bronchial wall caused by oxidative stress. Finally, treatment with H₂ did not interfere with the anti-tumor effects of gefitinib on a lung cancer cell line in vitro or on tumor-bearing mice in vivo. These results indicate that H₂-rich water has the potential to improve quality of life during gefitinib therapy by mitigating lung injury without impairing anti-tumor activity.

Effects of Molecular Hydrogen Assessed by an Animal Model and a Randomized Clinical Study on Mild Cognitive Impairment

BACKGROUND

Oxidative stress is one of the causative factors in the pathogenesis of neurodegenerative diseases including mild cognitive impairment (MCI) and dementia. We previously reported that molecular hydrogen (H2) acts as a therapeutic and preventive antioxidant.

OBJECTIVE

We assess the effects of drinking H2-water (water infused with H2) on oxidative stress model mice and subjects with MCI.

METHODS

Transgenic mice expressing a dominant-negative form of aldehyde dehydrogenase 2 were used as a dementia model. The mice with enhanced oxidative stress were allowed to drink H2-water. For a randomized double-blind placebo-controlled clinical study, 73 subjects with MCI drank ~300 mL of H2-water (H2-group) or placebo water (control group) per day, and the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) scores were determined after 1 year.

RESULTS

In mice, drinking H2-water decreased oxidative stress markers and suppressed the decline of memory impairment and neurodegeneration. Moreover, the mean lifespan in the H2-water group was longer than that of the control group. In MCI subjects, although there was no significant difference between the H2- and control groups in ADAS-cog score after 1 year, carriers of the apolipoprotein E4 (APOE4) genotype in the H2-group were improved significantly on total ADAS-cog score and word recall task score (one of the sub-scores in the ADAS-cog score).

CONCLUSION

H2-water may have a potential for suppressing dementia in an oxidative stress model and in the APOE4 carriers with MCI.

Recent Advances in Studies of Molecular Hydrogen against Sepsis

Sepsis is a syndrome comprised of a series of life-threatening organ dysfunctions caused by a maladjusted body response to infection with no effective treatment. Molecular hydrogen is a new type of antioxidant with strong free radical scavenging ability, which has been demonstrated to be effective for treating various diseases, such as infection, trauma, poisoning, organ ischemia-reperfusion, metabolic diseases, and tumors. Molecular hydrogen exerts multiple biological effects involving anti-inflammation, anti-oxidation, anti-apoptosis, anti-shock, and autophagy regulation, which may attenuate the organ and barrier damage caused by sepsis. However, the underlying molecular mechanisms remain elusive, but are likely related to the signaling pathways involved. This review focuses on the research progress and potential mechanisms of molecular hydrogen against sepsis to provide a theoretical basis for clinical treatment.

Hydrogen Indirectly Suppresses Increases in Hydrogen Peroxide in Cytoplasmic Hydroxyl Radical-Induced Cells and Suppresses Cellular Senescence

Bacteria inhabiting the human gut metabolize microbiota-accessible carbohydrates (MAC) contained in plant fibers and subsequently release metabolic products. Gut bacteria produce hydrogen (H₂), which scavenges the hydroxyl radical (•OH). Because H₂ diffuses within the cell, it is hypothesized that H₂ scavenges cytoplasmic •OH (cyto •OH) and suppresses cellular senescence. However, the mechanisms of cyto •OH-induced cellular senescence and the physiological role of gut bacteria-secreted H₂ have not been elucidated. Based on the pyocyanin-stimulated cyto •OH-induced cellular senescence model, the mechanism by which cyto •OH causes cellular senescence was investigated by adding a supersaturated concentration of H₂ into the cell culture medium. Cyto •OH-generated lipid peroxide caused glutathione (GSH) and heme shortage, increased hydrogen peroxide (H₂O₂), and induced cellular senescence via the phosphorylation of ataxia telangiectasia mutated kinase serine 1981 (p-ATM^ser1981)/p53 serine 15 (p-p53^ser15)/p21 and phosphorylation of heme-regulated inhibitor (p-HRI)/phospho-eukaryotic translation initiation factor 2 subunit alpha serine 51 (p-eIF2α)/activating transcription factor 4 (ATF4)/p16 pathways. Further, H₂ suppressed increased H₂O₂ by suppressing cyto •OH-mediated lipid peroxide formation and cellular senescence induction via two pathways. H₂ produced by gut bacteria diffuses throughout the body to scavenge cyto •OH in cells. Therefore, it is highly likely that gut bacteria-produced H₂ is involved in intracellular maintenance of the redox state, thereby suppressing cellular senescence and individual aging. Hence, H₂ produced by intestinal bacteria may be involved in the suppression of aging.

Administration of hydrogen-rich water prevents vascular aging of the aorta in LDL receptor-deficient mice

The main cause of arteriosclerosis is atherosclerosis in the aorta. Atherosclerosis is recognized as a chronic inflammatory condition that begins with the dysfunction or activation of arterial endothelium. Low-density lipoprotein (LDL) and especially its oxidized form play a key role in endothelial dysfunction and atherogenesis. Recent studies showed that senescent cells are involved in the development and progression of atherosclerosis, and eliminating senescent cells suppresses the senescence-associated secretory phenotype. We previously reported that molecular hydrogen-rich water (HW) has antioxidant and anti-inflammatory effects in numerous diseases. Here, we used LDL receptor-deficient mice fed a high-fat diet (HFD) for 13 weeks as a model for atherosclerosis and evaluated the effects of continuous administration of HW. The numbers of endothelial cells in the atheroma expressing the senescence factors p16^INK4a and p21 decreased in HFD-fed mice given HW compared with HFD-fed mice given control water. Furthermore, macrophage infiltration and Tnfα expression in the atheroma were also suppressed. These results suggest that vascular aging can be suppressed by HW.

Hydrogen attenuated oxidized low-density lipoprotein-induced inflammation through the stimulation of autophagy via sirtuin 1

Chronic inflammation is a central pathogenic mechanism underlying the induction and progression of atherosclerosis (AS). Hydrogen has been demonstrated to serve a protective role in diverse models of disease. However, the potential effects and mechanism of hydrogen with respect to ox-LDL-induced inflammation have not yet been completely elucidated. In the present study, various concentrations (0, 50 and 100 mg/l) of oxidized low-density lipoprotein (ox-LDL) were used to treat RAW264.7 cells. A Cell Counting kit-8 assay was used to determine cell viability and western blot analysis was performed to determine the expression of proteins that are involved in autophagy. The expression of inflammatory cytokines in ox-LDL-treated macrophages was detected using ELISA. Small interfering (si)RNA against sirtuin 1 (SIRT1) was employed to investigate the mechanism underlying hydrogen-activated autophagy. The results indicated that ox-LDL stimulation promoted inflammatory cytokine expression and impaired autophagic flux in RAW264.7 cells. Furthermore, hydrogen inhibited ox-LDL-induced inflammatory cytokine expression by upregulating autophagic flux. SIRT1 mediated the upregulation of autophagic flux via hydrogen in ox-LDL-treated macrophages. To conclude, the present study provided novel insights into the role of defective autophagy in the pathogenesis of AS and identified autophagy to be a promising therapeutic target for the treatment of AS. Notably, hydrogen may represent a potential agent for the treatment of AS.

Anti-inflammatory and antitumor action of hydrogen via reactive oxygen species

Hydrogen (H₂) has advantages that lead it to be used as a novel antioxidant in preventive and therapeutic applications. H₂ can permeate into biomembranes, cytosol, mitochondria and nuclei, and can be dissolved in water or saline to produce H₂ water or H₂-rich saline. H₂ selectively reduces oxidants of the detrimental reactive oxygen species (ROS), including hydroxyl radicals (·OH) and peroxynitrite (ONOO^-), which serve a causative role in the promotion of tumor cell proliferation, invasion and metastasis, but do not disturb metabolic oxidation-reduction reactions in cell signaling. Compared with traditional antioxidants, H₂ is a small molecule that can easily dissipate throughout the body and cells; thus, it may be a safe and effective antioxidant for inflammatory diseases and cancer, since ROS usually initiates tumor progression. Treatment with H₂ may involve correction of the oxidative/anti-oxidative imbalance and suppression of inflammatory mediators. Therefore the present review will discuss the anti-inflammatory and anti-tumorigenic action of H₂ via ROS.

Structural and lipid peroxidation effects of lead on rat hippocampus and its attenuation by hydrogen rich water

Despite the well-known toxicity and the efforts to control its exposure, lead still has a serious health concern, particularly in young ages. Chelation therapy cannot correct the neurocognitive effects of chronic exposure. So, there is a requirement to test different protective agents for lead intoxication. Hydrogen-rich water (HRW) has gained attraction recently as an antioxidant. Four groups of rats received sodium acetate, HRW, lead acetate (LA), or LA plus HRW for 8 weeks. Oxidative stress, histological and immunohistochemistry using p53 antibody were used to investigate the toxic effect of lead and the possible HRW protective effect in rat hippocampus. Results showed that HRW corrected the elevated malondialdehyde levels (MDA) and restore the lead-induced depletion of antioxidant enzymes; glutathione reductase (GR), catalase (CAT) and superoxide dismutase (SOD). HRW does not affect the diminished nitric oxide (NO) level in the LA-treated group. Moreover, HRW reversed the LA-induced histological and immunohistochemical changes. It significantly decreased the percentage of the apoptotic index. We concluded that HRW protects the neurons against lead-induced oxidative stress and has anti-apoptotic effects without a noticeable change in NO level which already was diminished by LA.

Preadministration of Hydrogen-Rich Water Protects Against Lipopolysaccharide-Induced Sepsis and Attenuates Liver Injury

Despite significant advances in antibiotic therapy and intensive care, sepsis remains the most common cause of death in intensive care units. We previously reported that molecular hydrogen (H2) acts as a therapeutic and preventive antioxidant. Here, we show that preadministration of H2-dissolved water (HW) suppresses lipopolysaccharide (LPS)-induced endotoxin shock in mice. Drinking HW for 3 days before LPS injection prolonged survival in a mouse model of sepsis. The H2 concentration immediately increased in the liver but not in the kidney after drinking HW. The protective effects of the preadministration of HW on LPS-induced liver injury were examined. Twenty-four hours after LPS injection, preadministration of HW reduced the increase in both apoptosis and oxidative stress. Moreover, preadministration of HW enhanced LPS-induced expression of heme oxyganase-1 and reduced endothelin-1 expression. These results indicate the therapeutic potential of HW in preventing acute injury of the liver with attenuation of an increase in oxidative stress. HW is likely to trigger adaptive responses against oxidative stress.

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 saline suppresses neuronal cell apoptosis and inhibits the p38 mitogen‑activated protein kinase‑caspase‑3 signaling pathway following cerebral ischemia‑reperfusion injury

Cerebral ischemia-reperfusion injury (CIRI) is a serious pathological disease that is associated with a high rate death and disability. Saturated hydrogen (H₂) saline exhibits brain protective functions through anti-inflammatory, antioxidant and antiapoptotic effects. The present study investigated the potential treatment effects of H₂ on CIRI. In addition, the potential protective mechanisms of H₂ in the prevention of CIRI were investigated. Adult, male Sprague-Dawley rats (n=60) were randomly divided into the following three groups: Sham-operated group; IR group; and IR + H₂ group (0.6 mmol/l, 0.5 ml/kg/day). Hematoxylin and eosin, and TUNEL staining were performed for histopathological analysis and investigation of apoptosis, respectively. In addition, the protein expression of caspase-3, p38 mitogen-activated protein kinase (MAPK) and phosphorylated-p38 MAPK in the cortex were measured by western blotting analysis. These results demonstrated that H₂ significantly reduced the number of apoptotic cells, and the protein expression of p38 MAPK and caspase-3, compared with the IR group. These effects may be associated with the p38MAPK signaling pathway.

Hydrogen-containing saline alleviates pressure overload-induced interstitial fibrosis and cardiac dysfunction in rats

Cardiac fibrosis induced by sustained pressure overload contributes to heart failure. Oxidative stress serves an important role in cardiac remodeling and heart failure independent of etiological factors. The application of hydrogen as an antioxidant is a novel concept in disease treatment, however no studies as present have investigated the effects of hydrogen on cardiac fibrosis. In the present study, the effects of hydrogen on pressure overload-induced cardiac fibrosis and heart failure were investigated in abdominal aortic-constricted rats. Masson's trichrome staining and echocardiography were used to evaluate the fibrotic area and cardiac function, respectively. Reactive oxygen species (ROS) content was detected by immunofluorescence. Malondialdehyde (MDA) concentration, the activity of superoxide dismutase (SOD) and hydroxyproline content were measured by spectrophotometry. Western blot analysis was used to detect the protein levels of transforming growth factor (TGF)-β1, connective tissue growth factor (CTGF), NADPH oxidases (NOX)2, NOX4, p38 mitogen-activated protein kinase (MAPK) and Smad2/3. Reverse transcription-quantitative polymerase chain reaction was performed to detect the mRNA expression of collagen I (Col I) and fibronectin 1 (FN1). Hydrogen-containing saline (HCS) treatment was observed to improve interstitial fibrosis and cardiac function and to decrease the level of ROS, the oxidative-stress marker MDA and expression of NOXs, while increasing the activity of the anti-oxidant enzyme SOD. HCS treatment also decreased the phosphorylation of p38 MAPK and Smad2/3, and the expression of TGF-β1 and CTGF, which were accompanied by reduced hydroxyproline content, Col I and FN1 mRNA levels. These results indicate that HCS treatment can improve cardiac function by reducing interstitial fibrosis in pressure-overloaded rats through its anti-oxidative properties and via suppression of TGF-β1 signaling.

Molecular Hydrogen as a Neuroprotective Agent

Oxidative stress and neuroinflammation cause many neurological disorders. Recently, it has been reported that molecular hydrogen (H2) functions as an antioxidant and anti-inflammatory agent. The routes of H2 administration in animal model and human clinical studies are roughly classified into three types, inhalation of H2 gas, drinking H2-dissolved water, and injection of H2-dissolved saline. This review discusses some of the remarkable progress that has been made in the research of H2 use for neurological disorders, such as cerebrovascular diseases, neurodegenerative disorders, and neonatal brain disorders. Although most neurological disorders are currently incurable, these studies suggest the clinical potential of H2 administration for their prevention, treatment, and mitigation. Several of the potential effectors of H2 will also be discussed, including cell signaling molecules and hormones that are responsible for preventing oxidative stress and inflammation. Nevertheless, further investigation will be required to determine the direct target molecule of H2.

Protective effects of molecular hydrogen on steroid-induced osteonecrosis in rabbits via reducing oxidative stress and apoptosis

Background

The objective of this study was to investigate the protective effects of molecular hydrogen, a novel and selective antioxidant, on steroid-induced osteonecrosis (ON) in a rabbit model.

Methods

Sixty rabbits were randomly divided into two groups (model group and hydrogen group). Osteonecrosis was induced according to an established protocol of steroid-induced ON. Rabbits in the hydrogen group were treated with intraperitoneal injections of molecular hydrogen at 10 ml/kg body weight for seven consecutive days. Plasma levels of total cholesterol, triglycerides, soluble thrombomodulin(sTM), glutathione(GSH) and malondialdehyde(MDA) were measured before and after steroid administration. The presence or absence of ON was examined histopathologically. Oxidative injury and vascular injury were assessed in vivo by immunohistochemical staining of 8-hydoxy-2-deoxyguanosine(8-OHdG) and MDA, and ink artery infusion angiography. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays were performed to measure apoptosis.

Results

The incidence of steroid-induced ON was significantly lower in hydrogen group (28.6%) than that in model group (68.0%). No statistically differences were observed on the levels of total cholesterol and triglycerides. Oxidative injury, vascular injury and apoptosis were attenuated in the hydrogen group compared with those in the model group in vivo.

Conclusions

These results suggested that molecular hydrogen prevents steroid-induced osteonecrosis in rabbits by suppressing oxidative injury, vascular injury and apoptosis.

Hydrogen-rich saline improves non‑alcoholic fatty liver disease by alleviating oxidative stress and activating hepatic PPARα and PPARγ

Non-alcoholic fatty liver disease (NAFLD) comprises a range of liver diseases, between steatosis and non‑alcoholic steatohepatitis and liver cirrhosis, which are closely associated with diabetes mellitus. Previous studies have indicated that oxidative stress is a key factor in the development of NAFLD. Molecular hydrogen (H2) may ameliorate oxidative stress injuries by selectively neutralizing peroxynitrite and hydroxyl radicals. The present study evaluated the effects of H2 on NAFLD in rats and concluded that H2‑rich saline had significant therapeutic effects on NAFLD induced by hyperglycemia and hyperlipidemia, as demonstrated by hematoxylin and eosin and terminal deoxynucleotidyl-transferase‑mediated dUTP nick end labeling staining. H2‑rich saline improved fasting blood glucose, fasting insulin, insulin sensitivity and glucose tolerance, and lowered the expression levels of tumor necrosis factor alpha, interleukin‑1 beta, 3‑nitrotyrosine and 8‑hydroxy‑2'‑deoxyguanosine in the liver. In addition, the present study revealed that H2‑rich saline could significantly increase peroxisome proliferator‑activated receptor (PPAR) α and PPARγ expression in hepatocytes. In conclusion, H2‑rich saline may significantly improve NAFLD, possibly by reducing oxidative stress and activating hepatic PPARα and PPARγ expression.

Molecular Hydrogen Alleviates Cellular Senescence in Endothelial Cells

BACKGROUND

Substantial evidence indicates that molecular hydrogen (H2) has beneficial vascular effects because of its antioxidant and/or anti-inflammatory effects. Thus, hydrogen-rich water may prove to be an effective anti-aging drink. This study examined the effects of H2on endothelial senescence and clarified the mechanisms involved.

METHODS AND RESULTS

Hydrogen-rich medium was produced by a high-purity hydrogen gas generator. Human umbilical vein endothelial cells (HUVECs) were incubated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for various time periods in normal or hydrogen-rich medium. The baseline H2concentration in hydrogen-rich medium was 0.55±0.07 mmol/L. This concentration gradually decreased, and H2was almost undetectable in medium after 12 h. At 24 h after TCDD exposure, HUVECs treated with TCDD exhibited increased 8OHdG and acetyl-p53 expression, decreased nicotinamide adenine dinucleotide (NAD(+))/NADH ratio, impaired Sirt1 activity, and enhanced senescence-associated β-galactosidase. However, HUVECs incubated in hydrogen-rich medium did not exhibit these TCDD-induced changes accompanying Nrf2 activation, which was observed even after H2was undetectable in the medium. Chrysin, an inhibitor of Nrf2, abolished the protective effects of H2on HUVECs.

CONCLUSIONS

H2has long-lasting antioxidant and anti-aging effects on vascular endothelial cells through the Nrf2 pathway, even after transient exposure to H2. Hydrogen-rich water may thus be a functional drink that increases longevity. (Circ J 2016; 80: 2037-2046).

Hydrogen-rich saline attenuated neuropathic pain by reducing oxidative stress

BACKGROUND

Reactive oxygen species (ROS) are often associated with persistent pains such as neuropathic and inflammatory pain. Hydrogen gas can reduce ROS and alleviate cerebral, myocardial, and hepatic ischemia/reperfusion injuries. In the present study, we aim to investigate whether hydrogen-rich saline can reduce neuropathic pain in a rat model of chronic constriction injury (CCI).

METHODS

Thirty SD rats were randomly divided into three groups: sham group was administered sodium chloride by intrathecal injection (n=10); control groups underwent CCI surgery and were administered sodium chloride by intrathecal injection (n=10); vehicle group underwent CCI surgery and was administered hydrogen-rich saline by intrathecal injection (n=10). Drugs were administered in the dose of 100 ul/kg once a day at 0.5 hours before and 1-7 day after CCI surgery. The mechanical thresholds were tested at one day before and 3-14 day after CCI surgery.

RESULTS

We found that hydrogen-rich saline significantly elevated the mechanical thresholds of neuropathic pain compared to vehicle (physiologic saline) control in CCI rats (p<0.05); it also decreased the levels of myeloperoxidase, maleic dialdehyde, and protein carbonyl in spinal cord by 7 days post-chronic constriction injury(p<0.05). In addition, hydrogen-rich saline also suppressed the expression of p38-mitogen-activated protein kinase (p38MAPK) and brain-derived neurotrophic factor (BDNF) in the spinal cord by 7 days post-chronic constriction injury (p<0.01, p<0.01, respectively), but had no effect on P2X4R (p>0.05), an ATP receptor.

CONCLUSION

Intrathecal injection of hydrogen-rich saline can decrease oxidative stress and the expression of p38MAPK and BDNF that may contribute to the elevated threshold of neuropathic pain in rat CCI model.

Le salin riche en hydrogène atténue la douleur névropathique en réduisant le stress oxydatif.

Effects of hydrogen-rich saline on aquaporin 1, 5 in septic rat lungs

Aquaporin 1(AQP1) and AQP5 have an important role in eliminating extravascular lung water, an increase of which contributes to lung injury in patients with sepsis and its consequent mortality. It has been reported that hydrogen-rich saline (HRS) has protective effects against sepsis-related lung injury. In this study, we hypothesized that the protective effect occurred by preserving the expression of AQP1 and AQP5. To test this hypothesis, male Sprague-Dawley rats received intratracheal administration of lipopolysaccharide (LPS) followed by intraperitoneal injection of HRS. Lung function, wet-to-dry weight ratio, and histopathology scores were determined. The expression of AQP1 and AQP5 at the messenger RNA and protein levels, as well as the involved pathways, was explored by quantitative polymerase chain reaction and Western blot. LPS significantly impaired lung function and downregulated the expression of AQP1 and AQP5 in the rat lung, all of which were attenuated by HRS treatment. Moreover, HRS treatment inhibited LPS-induced activation of p38 mitogen-activated protein kinase and jun N-terminal kinase, which is associated with LPS-induced downregulation of AQP1 and AQP5.