Molecular hydrogen improves obesity and diabetes by inducing hepatic FGF21 and stimulating energy metabolism in db/db 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.

Prospects of molecular hydrogen in cancer prevention and treatment

Gas signaling molecules, including carbon monoxide (CO), nitric oxide (NO), and hydrogen sulfide (H2S), have been shown to have cancer therapeutic potential, pointing to a new direction for cancer treatment. In recent years, a series of studies have confirmed that hydrogen (H2), a weakly reductive gas, also has therapeutic effects on various cancers and can mitigate oxidative stress caused by radiation and chemotherapy, reducing tissue damage and immunosuppression to improve prognosis. Meanwhile, H2 also has immunomodulatory effects, inhibiting T cell exhaustion and enhancing T cell anti-tumor function. It is worth noting that human intestinal flora can produce large amounts of H2 daily, which becomes a natural barrier to maintaining the body's resistance to diseases such as tumors. Although the potential anti-tumor mechanisms of H2 are still to be investigated, previous studies have shown that H2 can selectively scavenge highly toxic reactive oxygen species (ROS) and inhibit various ROS-dependent signaling pathways in cancer cells, thus inhibiting cancer cell proliferation and metastasis. The ROS scavenging ability of H2 may also be the underlying mechanism of its immunomodulatory function. In this paper, we review the significance of H2 produced by intestinal flora on the immune homeostasis of the body, the role of H2 in cancer therapy and the underlying mechanisms, and the specific application of H2 to provide new ideas for the comprehensive treatment of cancer patients.

Zn-Fe primary battery-enabled controlled hydrogen release in stomach for improving insulin resistance in obesity-associated type 2 diabetes

Chronic systemic inflammation in obesity-associated type 2 diabetes (T2D) is a key inducing factor of insulin resistance (IR). Hydrogen molecule (H2) has been proved to be a safe and effective anti-inflammatory agent, but conventional H2 administration methods cannot provide a high dosage and a long duration of H2 treatment in IR-related tissues and thus lead to limited therapeutic efficacies. We here propose a new strategy of controlled H2 release to match the time window of gastric emptying for maximizing the bioavailability and therapeutic outcome of H2. This work enhances the hydrolysis rate of Zn by constructing a Zn-Fe primary-battery micro-/nano-structure, and the H2-releasing rate is adjusted by tuning the ratio of Zn to Fe. The Zn-Fe micro-/nano-structure is orally administrated once daily to alleviate obesity-associated T2D in a leptin-deficient (ob/ob) mouse model. The H2 generation time of the Zn-Fe primary-battery micro-/nano-structure with the Fe/Zn ratio of 1:100 in gastric acid is about 3 h, just matching with the time window of gastric emptying in mice. In vivo monitoring results show that H2 generated by Zn-Fe micro-/nano-structure in stomach can effectively accumulate in major IR-sited tissues including liver, adipose tissue, and skeletal muscle at a high dose for a relatively long time compared to H2-rich water drinking. Oral administration of Zn-Fe micro-/nano-structure at 200 mg/kg body weight has realized an efficient IR improvement and remarkably ameliorated systemic inflammation in ob/ob mice. In addition, a high-dose administration of Zn-Fe shows no visible toxicity in mice. This work provides a new strategy to maximize the outcome of hydrogen therapy.

Advancing piezoelectric 2D nanomaterials for applications in drug delivery systems and therapeutic approaches

Precision drug delivery and multimodal synergistic therapy are crucial in treating diverse ailments, such as cancer, tissue damage, and degenerative diseases. Electrodes that emit electric pulses have proven effective in enhancing molecule release and permeability in drug delivery systems. Moreover, the physiological electrical microenvironment plays a vital role in regulating biological functions and triggering action potentials in neural and muscular tissues. Due to their unique noncentrosymmetric structures, many 2D materials exhibit outstanding piezoelectric performance, generating positive and negative charges under mechanical forces. This ability facilitates precise drug targeting and ensures high stimulus responsiveness, thereby controlling cellular destinies. Additionally, the abundant active sites within piezoelectric 2D materials facilitate efficient catalysis through piezochemical coupling, offering multimodal synergistic therapeutic strategies. However, the full potential of piezoelectric 2D nanomaterials in drug delivery system design remains underexplored due to research gaps. In this context, the current applications of piezoelectric 2D materials in disease management are summarized in this review, and the development of drug delivery systems influenced by these materials is forecast.

Acute effect of hydrogen-rich water on physical, perceptual and cardiac responses during aerobic and anaerobic exercises: a randomized, placebo-controlled, double-blinded cross-over trial

Molecular hydrogen (H2 gas) dissolved in water to produce Hydrogen-Rich Water. Hydrogen-Rich Water (HRW) is considered as ergogenic aid in different exercise modes. However, acute pre-exercise HRW ingestion effect is unclear regarding athlete performance. This study aimed at investigating acute effect of HRW ingestion on aerobic and anaerobic exercise performance. Twenty-two male amateur middle-distance runners volunteered to participate in this study. In a randomized, double-blind study design, all players ingested 500 mL of HRW or placebo (PLA) supplement 30 min before the start of the tests. Over 4 days, maximal aerobic speed of Vameval test (MAS), time to exhaustion at MAS (Tlim), squat jump (SJ), counter-movement jump (CMJ) and five jump test (5JT) were evaluated. Also, rate of perceived exertion (RPE) and peak heart rate (HRpeak) were measured during the aerobic tests. For Vameval test, HRW ingestion improved MAS, HRpeak and RPE compared with the placebo condition. For Tlim test, HRW ingestion demonstrated improvements in time to exhaustion, RPE and HRpeak. However, no significant change was observed between HW and placebo conditions in SJ, CMJ, 5JT. 500 mL of HRW can significantly improve HRpeak, time to exhaustion, RPE, with no significant effect on MAS, jumping performance in amateur endurance athletes.

Mitochondria: one of the vital hubs for molecular hydrogen's biological functions

As a novel antioxidant, a growing body of studies has documented the diverse biological effects of molecular hydrogen (H2) in a wide range of organisms, spanning animals, plants, and microorganisms. Although several possible mechanisms have been proposed, they cannot fully explain the extensive biological effects of H2. Mitochondria, known for ATP production, also play crucial roles in diverse cellular functions, including Ca2+ signaling, regulation of reactive oxygen species (ROS) generation, apoptosis, proliferation, and lipid transport, while their dysfunction is implicated in a broad spectrum of diseases, including cardiovascular disorders, neurodegenerative conditions, metabolic disorders, and cancer. This review aims to 1) summarize the experimental evidence on the impact of H2 on mitochondrial function; 2) provide an overview of the mitochondrial pathways underlying the biological effects of H2, and 3) discuss H2 metabolism in eukaryotic organisms and its relationship with mitochondria. Moreover, based on previous findings, this review proposes that H2 may regulate mitochondrial quality control through diverse pathways in response to varying degrees of mitochondrial damage. By combining the existing research evidence with an evolutionary perspective, this review emphasizes the potential hydrogenase activity in mitochondria of higher plants and animals. Finally, this review also addresses potential issues in the current mechanistic study and offers insights into future research directions, aiming to provide a reference for future studies on the mechanisms underlying the action of H2.

The Effect of Adjuvant Therapy with Molecular Hydrogen on Endogenous Coenzyme Q10 Levels and Platelet Mitochondrial Bioenergetics in Patients with Non-Alcoholic Fatty Liver Disease

Molecular hydrogen (H2) has been recognized as a novel medical gas with antioxidant and anti-inflammatory effects. Non-alcoholic fatty liver disease (NAFLD) is a liver pathology with increased fat accumulation in liver tissue caused by factors other than alcohol consumption. Platelet mitochondrial function is considered to reflect systemic mitochondrial health. We studied the effect of adjuvant therapy with hydrogen-rich water (HRW) on coenzyme Q10 (CoQ10) content and platelet mitochondrial bioenergetics in patients with NAFLD. A total of 30 patients with NAFLD and 15 healthy volunteers were included in this clinical trial. A total of 17 patients (H2 group) drank water three × 330 mL/day with tablets producing HRW (>4 mg/L H2) for 8 weeks, and 13 patients (P group) drank water with placebo tablets producing CO2. The concentration of CoQ10-TOTAL was determined by the HPLC method, the parameter of oxidative stress, thiobarbituric acid reactive substances (TBARS), by the spectrophotometric method, and mitochondrial bioenergetics in platelets isolated from whole blood by high-resolution respirometry. The patients with NAFLD had lower concentrations of CoQ10-TOTAL in the blood, plasma, and platelets vs. the control group. Mitochondrial CI-linked LEAK respiration was higher, and CI-linked oxidative phosphorylation (OXPHOS) and CII-linked electron transfer (ET) capacities were lower vs. the control group. Plasma TBARS concentrations were higher in the H2 group. After 8 weeks of adjuvant therapy with HRW, the concentration of CoQ10 in platelets increased, plasma TBARS decreased, and the efficiency of OXPHOS improved, while in the P group, the changes were non-significant. Long-term supplementation with HRW could be a promising strategy for the acceleration of health recovery in patients with NAFLD. The application of H2 appears to be a new treatment strategy for targeted therapy of mitochondrial disorders. Additional and longer-term studies are needed to confirm and elucidate the exact mechanisms of the mitochondria-targeted effects of H2 therapy in patients with NAFLD.

Evaluation of the safety and potential lipid-lowering effects of oral hydrogen-rich coral calcium (HRCC) capsules in patients with metabolic syndrome: a prospective case series study

Background

Metabolic syndrome is characterized by a cluster-like occurrence of conditions such as hypertension, hyperglycaemia, elevated low-density lipoprotein (LDL) cholesterol or triglycerides (TG) and high visceral fat. Metabolic syndrome is linked to the build-up of plaque within the artery, which leads to disorders of the circulatory, nervous and immune systems. A variety of treatments target the regulation of these conditions; nevertheless, they remain dominant risk factors for the development of type 2 diabetes (T2DM) and cardiovascular disease (CVD), which affect 26.9% of the US population. Management and intervention strategies for improving cholesterol and/or TG are worthwhile, and recent studies on hydrogen treatment are promising, particularly as molecular hydrogen is easily ingested. This study aimed to investigate the lipid-lowering effects and quality of life (QOL) improvement of hydrogen-rich coral calcium (HRCC) in patients with metabolic syndrome.

Methods

The patients, all Taiwanese, were randomly assigned to 3 different doses (low, medium, and high) of HRCC capsules. The primary outcome was the adverse effects/symptoms during this 4-week use of HRCC capsules. The secondary outcome was lipid profile changes. Complete blood count, inflammatory biomarkers, and QOL were also measured before and after the course of HRCC.

Results

Sixteen patients with metabolic syndrome completed this study (7 males, 9 females; mean age: 62 years; range: 32-80). No obvious adverse effects were recorded. Only changes in blood TG reached significance. The baseline TG value was 193.19 μL (SD = 107.44), which decreased to 151.75 μL (SD = 45.27) after 4 weeks of HRCC (p = 0.04). QOL showed no significant changes.

Conclusion

This study is the first human clinical trial evaluating HRCC capsules in patients with metabolic syndrome. Based on the safety and potential TG-lowering effects of short-term HRCC, further long-term investigations of HRCC are warranted.

Clinical trial registration

[ClinicalTrials.gov], identifier [NCT05196295].

Real-World Effectiveness and Safety of Hydrogen Inhalation in Chinese Patients with Type 2 Diabetes: A Single-Arm, Retrospective Study

Aim

To evaluate the real-life effectiveness and safety of Chinese patients with type 2 diabetes mellitus (T2DM) receiving hydrogen inhalation (HI) treatment as a supplementary treatment.

Methods

This retrospective, multicenter, observational 6-months clinical study included T2DM patients maintaining HI, visited at 4 time points. The primary outcome is the mean change in glycated hemoglobin (HbA1c) at the end of the study compared to baseline. The secondary outcome is analyzing the mean change of fasting plasma glucose (FPG), weight, lipid profile, insulin dose and homeostasis model assessment. Linear regression and logistics regression are applied to evaluate the effect of HI after the treatment.

Results

Of the 431 patients comprised, it is observed a significant decrease in HbA1c level (9.04±0.82% at baseline to 8.30±0.99% and 8.00±0.80% at the end, p<0.001), FPG (165.6±40.2 mg/dL at baseline to 157.1±36.3mg/dL and 143.6±32.3mg/dL at the end, p<0.001), weight (74.7±7.1kg at baseline to 74.8±10.0kg and 73.6±8.1kg at the end, p<0.001), insulin dose (49.3±10.8U/d at baseline to 46.7±8.0U/d and 45.2±8.7U/d, p<0.001). The individuals in subgroup with higher baseline HbA1c and longer daily HI time duration gain greater HbA1c decrease after 6 months. Linear regression shows that higher baseline HbA1c level and shorter diabetes duration are significantly in relation to greater HbA1c reduction. Logistics regression reveals that lower weight is associated with a higher possibility of reaching HbA1c<7%. The most common adverse event is hypoglycemia.

Conclusion

HI therapy significantly improves glycemic control, weight, insulin dose, lipid metabolism, β-cell function and insulin resistance of patients with type 2 diabetes after 6 months. Higher baseline HbA1c level and shorter diabetes duration is related to greater clinical response to HI.

Hydrogen-Rich Water Ameliorates Metabolic Disorder via Modifying Gut Microbiota in Impaired Fasting Glucose Patients: A Randomized Controlled Study

OBJECTIVE

Molecular hydrogen (H₂) exhibits antioxidant, anti-inflammatory and anti-apoptotic effects, and has shown benefits in glucose and lipid metabolism in certain animal metabolic disorder models. However, the potential benefits of H₂ treatment in individuals with impaired fasting glucose (IFG) has seldom been studied. This randomized controlled study (RCT) aims to investigate the effects of hydrogen-rich water (HRW) on IFG subjects and explore the underlying mechanism involved.

METHODS

Seventy-three patients with IFG were enrolled in a randomized, double-blind, placebo-controlled clinical study. These patients were assigned to receive either 1000 mL per day of HRW or placebo pure water (no H₂ infusion) for a duration of eight weeks. Metabolic parameters and fecal gut microbiota were assessed at baseline (week 0) and at week 8. A combined analysis of metabolomics and intestinal microbiota was conducted to investigate the correlation between the effect of H₂ on the metabolisms and the diversity of intestinal flora in the IGF patients.

RESULTS

Both pure water and HRW demonstrated a significant reduction in fasting blood glucose in IFG patients, with a significant difference between pure water and HRW after eight weeks. Among IFG patients with abnormal pre-experimental fatty liver, 62.5% (10/16) in the HRW group and 31.6% (6/19) in the pure water group achieved remission. Furthermore, 16S RNA analysis revealed HRW-modified gut microbiota dysbiosis in the fecal samples of IGF patients. Through Pearson correlation analysis, the differential gut microbiota obtained by 16S analysis was found to be highly correlated with nine metabolites.

CONCLUSION

H₂ slightly improved metabolic abnormalities and gut microbiota dysbiosis, providing a novel target and theoretical basis for the prevention and treatment of blood glucose regulation in patients with IFG.

Molecular Hydrogen Mediates Neurorestorative Effects After Stroke in Diabetic Rats: the TLR4/NF-κB Inflammatory Pathway

Diabetes is an independent risk factor for stroke and amplifies inflammation. Diabetic stroke is associated with a higher risk of death and worse neural function. The identification of effective anti-inflammatory molecules with translational advantages is particularly important to promote perioperative neurorestorative effects. Applying molecular hydrogen, we measured blood glucose levels before and after middle cerebral artery occlusion (MCAO), 48-h cerebral oedema and infarct volumes, as well as 28-day weight, survival and neurological function. We also measured the levels of TLR4, NF-κB p65, phosphorylated NF-κB p65, catecholamines, acetylcholine and inflammatory factors. All measurements comprehensively showed the positive effect and translational advantage of molecular hydrogen on diabetic stroke. Molecular hydrogen improved the weight, survival and long-term neurological function of rats with diabetic stroke and alleviated changes in blood glucose levels before and after middle cerebral artery occlusion (MCAO), but no difference in circadian rhythm was observed. Molecular hydrogen inhibited the phosphorylation of NF-κB and significantly reduced inflammation. Molecular hydrogen mediates neurorestorative effects after stroke in diabetic rats. The effect is independent of circadian rhythms, indicating translational advantages. The molecular mechanism is related to the TLR4/NF-κB pathway and inflammation. Molecular hydrogen (H2) affects outcomes of ischemic stroke with diabetes mellitus (DM).

Hydrogen gas ameliorates acute alcoholic liver injury via anti-inflammatory and antioxidant effects and regulation of intestinal microbiota

Alcoholic liver disease (ALD) is a globally prevalent liver-related disorder characterized by severe oxidative stress and inflammatory liver damage, for which no effective treatment is currently available. Hydrogen gas (H₂) has been demonstrated to be an efficient antioxidant in various diseases in animals as well as humans. However, the protective effects of H₂ on ALD and its underlying mechanisms remain to be elucidated. The present study demonstrated that H₂ inhalation ameliorated liver injury, and attenuated liver oxidative stress, inflammation, and steatosis in an ALD mouse model. Moreover, H₂ inhalation improved gut microbiota, including increasing the abundance of Lachnospiraceae and Clostridia, and decreasing the abundance of Prevotellaceae and Muribaculaceae, and also improved intestinal barrier integrity. Mechanistically, H₂ inhalation blocked activation of the LPS/TLR4/NF-κB pathway in liver. Notably, it was further demonstrated that the reshaped gut microbiota may accelerate alcohol metabolism, regulate lipid homeostasis and maintain immune balance by bacterial functional potential prediction (PICRUSt). Fecal microbiota transplantation from mice that had undergone H₂ inhalation significantly alleviated acute alcoholic liver injury. In summary, the present study showed that H₂ inhalation alleviated liver injury by reducing oxidative stress and inflammation, while also improving intestinal flora and enhancing the intestinal barrier. H₂ inhalation may serve as an effective intervention for preventing and treating ALD in a clinical context.

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.

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.

Molecular Hydrogen: an Emerging Therapeutic Medical Gas for Brain Disorders

Oxidative stress and neuroinflammation are the main physiopathological changes involved in the initiation and progression of various neurodegenerative disorders or brain injuries. Since the landmark finding reported in 2007 found that hydrogen reduced the levels of peroxynitrite anions and hydroxyl free radicals in ischemic stroke, molecular hydrogen's antioxidative and anti-inflammatory effects have aroused widespread interest. Due to its excellent antioxidant and anti-inflammatory properties, hydrogen therapy via different routes of administration exhibits great therapeutic potential for a wide range of brain disorders, including Alzheimer's disease, neonatal hypoxic-ischemic encephalopathy, depression, anxiety, traumatic brain injury, ischemic stroke, Parkinson's disease, and multiple sclerosis. This paper reviews the routes for hydrogen administration, the effects of hydrogen on the previously mentioned brain disorders, and the primary mechanism underlying hydrogen's neuroprotection. Finally, we discuss hydrogen therapy's remaining issues and challenges in brain disorders. We conclude that understanding the exact molecular target, finding novel routes, and determining the optimal dosage for hydrogen administration is critical for future studies and applications.

Therapeutic Inhalation of Hydrogen Gas for Alzheimer’s Disease Patients and Subsequent Long-Term Follow-Up as a Disease-Modifying Treatment: An Open Label Pilot Study

(1) Background: Alzheimer’s disease (AD) is a progressive and fatal neurodegenerative disorder. Hydrogen gas (H2) is a therapeutic medical gas with multiple functions such as anti-oxidant, anti-inflammation, anti-cell death, and the stimulation of energy metabolism. To develop a disease-modifying treatment for AD through multifactorial mechanisms, an open label pilot study on H2 treatment was conducted. (2) Methods: Eight patients with AD inhaled 3% H2 gas for one hour twice daily for 6 months and then followed for 1 year without inhaling H2 gas. The patients were clinically assessed using the Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-cog). To objectively assess the neuron integrity, diffusion tensor imaging (DTI) with advanced magnetic resonance imaging (MRI) was applied to neuron bundles passing through the hippocampus. (3) Results: The mean individual ADAS-cog change showed significant improvement after 6 months of H2 treatment (−4.1) vs. untreated patients (+2.6). As assessed by DTI, H2 treatment significantly improved the integrity of neurons passing through the hippocampus vs. the initial stage. The improvement by ADAS-cog and DTI assessments were maintained during the follow-up after 6 months (significantly) or 1 year (non-significantly). (4) Conclusions: This study suggests that H2 treatment not only relieves temporary symptoms, but also has disease-modifying effects, despite its limitations.

Transgenic type2 diabetes mouse models for in vivo redox measurement of hepatic mitochondrial oxidative stress

BACKGROUND

Oxidative stress is involved in the progression of diabetes and its associated complications. However, it is unclear whether increased oxidative stress plays a primary role in the onset of diabetes or is a secondary indicator caused by tissue damage. Previous methods of analyzing oxidative stress have involved measuring the changes in oxidative stress biomarkers. Our aim is to identify a novel approach to clarify whether oxidative stress plays a primary role in the onset of diabetes.

METHODS

We constructed transgenic type 2 diabetes mouse models expressing redox-sensitive green fluorescent proteins (roGFPs) that distinguished between mitochondria and whole cells. Pancreas, liver, skeletal muscle, and kidney redox states were measured in vivo.

RESULTS

Hepatic mitochondrial oxidation increased when the mice were 4 weeks old and continued to increase in an age-dependent manner. The increase in hepatic mitochondrial oxidation occurred simultaneously with weight gain and increased blood insulin levels before the blood glucose levels increased. Administering the oxidative stress inducer acetaminophen increased the vulnerability of the liver mitochondria to oxidative stress.

CONCLUSIONS

This study demonstrates that oxidative stress in liver mitochondria in mice begins at the onset of diabetes rather than after the disease has progressed.

GENERAL SIGNIFICANCE

RoGFP-expressing transgenic type 2 diabetes mouse models are effective and convenient tools for measuring hepatic mitochondrial redox statuses in vivo. These models may be used to assess mitochondria-targeting antioxidants and establish the role of oxidative stress in type 2 diabetes.

Hydrogen Gas Improves the Postharvest Quality of Lanzhou Lily (Lilium davidii var. unicolor) Bulbs

Hydrogen gas (H₂) is an important molecular messenger in animal and plant cells and is involved in various aspects of plant processes, including root organogenesis induction, stress tolerance and postharvest senescence. This study investigated the effect of H₂ fumigation on the quality of Lanzhou lily scales. The results indicated the H₂ remarkably declined the color variation and browning degree in Lanzhou lily scales by suppressing the activity of phenylalanine ammonia-lyase (PAL), peroxidase (POD) and polyphenol oxidase (PPO). Moreover, H₂ significantly alleviated the degradation of soluble proteins and soluble sugars in Lanzhou lily scales during postharvest storage, mitigating the decline in nutritional quality. This alleviating effect of H₂ might be achieved by increasing the endogenous H₂ concentration. Collectively, our data provide new insights into the postharvest quality reduction of Lanzhou lily scales mitigated by H₂ fumigation.

The Effects of Hydrogen-Rich Water on Blood Lipid Profiles in Clinical Populations: A Systematic Review and Meta-Analysis

Over the last two decades, a plethora of disease models and human studies have confirmed the beneficial effects of molecular hydrogen (H2), a simple biotherapeutic gas. Recent small-scale studies evaluating the effects of hydrogen-rich water (HRW) on various metabolic conditions pointed to advantageous effects of HRW in regulating blood lipid profiles. However, to the best of the authors' knowledge, no systematic review and/or meta-analysis (SRMA) were published considering HRW consumption and lipid/lipoprotein status. Therefore, the aim of this SRMA was to assess the effects of HRW consumption on blood lipid panel in clinical populations. The search strategy was designed using PRISMA guidelines, and the databases PubMed/Medline, Web of Science, and Scopus were explored from inception until 4 October 2022. A total of seven studies satisfied all the eligibility criteria and were included in SRMA. The results for the pooled meta-analysis showed a significant reduction in total cholesterol, low-density lipoprotein, and triglycerides after HRW intake (p = 0.01), with small to moderate effects (pooled SMD = -0.23 (from -0.40 to 0.05); pooled SMD = -0.22 (from -0.39 to 0.04); pooled SMD = -0.38 (from -0.59 to 0.18), respectively). Our findings indicate that drinking HRW can significantly improve lipid status in the clinical populations. Additional studies are warranted to further validate this connection.

Effectiveness and safety of hydrogen inhalation as an adjunct treatment in Chinese type 2 diabetes patients: A retrospective, observational, double-arm, real-life clinical study

Aim

To analyze the effectiveness and safety of hydrogen inhalation (HI) therapy as an adjunct treatment in Chinese type 2 diabetes mellitus (T2DM) patients in a real-life clinical setting.

Methods

This observational, non-interventional, retrospective, double-arm, 6-month clinical study included T2DM patients receiving conventional anti-diabetes medication with or without HI initiation from 2018 to 2021. Patients were assigned to the HI group or non-HI group (control group) after 1:1 propensity score matching (PSM). The mean change in glycated hemoglobin (HbA1c) after 6 months in different groups was evaluated primarily. The secondary outcome was composed of the mean change of fasting plasma glucose (FPG), weight, lipid profile, and homeostasis model assessment. Logistics regression was performed to evaluate the likelihood of reaching different HbA1c levels after 6-month treatment between the groups. Adverse event (AE) was also evaluated in patients of both groups.

Results

In total, 1088 patients were selected into the analysis. Compared to the control group, subjects in HI group maintained greater improvement in the level of HbA1c (-0.94% vs -0.46%), FPG (-22.7 mg/dL vs -11.7 mg/dL), total cholesterol (-12.9 mg/dL vs -4.4 mg/dL), HOMA-IR (-0.76 vs -0.17) and HOMA-β (8.2% vs 1.98%) with all p< 0.001 post the treatment. Logistics regression revealed that the likelihood of reaching HbA1c< 7%, ≥ 7% to< 8% and > 1% reduction at the follow-up period was higher in the HI group, while patients in the control group were more likely to attain HbA1c ≥ 9%. Patients in HI group was observed a lower incidence of several AEs including hypoglycemia (2.0% vs 6.8%), vomiting (2.6% vs 7.4%), constipation (1.7% vs 4.4%) and giddiness (3.3% vs 6.3%) with significance in comparison to the control group.

Conclusion

HI as an adjunct therapy ameliorates glycemic control, lipid metabolism, insulin resistance and AE incidence of T2DM patients after 6-month treatment, presenting a noteworthy inspiration to existing clinical diabetic treatment.

Ameliorating Role of Hydrogen-Rich Water Against NSAID-Induced Enteropathy via Reduction of ROS and Production of Short-Chain Fatty Acids

BACKGROUND

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy, the mechanism of which is involved in oxidative stress, can be lethal due to hemorrhage. Thus, we aimed to investigate the effect of hydrogen-rich water (HRW), in terms of oxidative stress, on intestinal mucosal damage as well as changes in the gut microbiome and the short-chain fatty acids (SCFAs) content in feces.

METHODS

Hydrogen-rich water was orally administered for 5 days to investigate the effectiveness of indomethacin-induced enteropathy in mice. Small intestinal damage and luminal reactive oxygen species (ROS) were evaluated to investigate the ameliorating effects of hydrogen. Then, components of the gut microbiome were analyzed; fecal microbiota transplantation (FMT) was performed using the cecal contents obtained from mice drinking HRW. The cecal contents were analyzed for the SCFAs content. Finally, cells from the macrophage cell line RAW264 were co-cultured with the supernatants of cecal contents.

RESULTS

Hydrogen-rich water significantly ameliorated IND-induced enteropathy histologically and reduced the expression of IND-induced inflammatory cytokines. Microscopic evaluation revealed that luminal ROS was significantly reduced and that HRW did not change the gut microbiota; however, FMT from HRW-treated animals ameliorated IND-induced enteropathy. The SCFA content in the cecal contents of HRW-treated animals was significantly higher than that in control animals. The supernatant had significantly increased interleukin-10 expression in RAW264 cells in vitro.

CONCLUSION

Hydrogen-rich water ameliorated NSAID-induced enteropathy, not only via direct antioxidant effects but also via anti-inflammatory effects by increasing luminal SCFAs. These results suggest that hydrogen may have therapeutic potential in small intestinal inflammatory diseases.

Accurate in vivo real-time determination of the hydrogen concentration in different tissues of mice after hydrogen inhalation

As an antioxidant, anti-inflammatory and anti-apoptotic agent, hydrogen (H₂) shows a promising potential in basic and clinical research against various diseases owing to its safety and efficacy. However, knowledge involving its underlying mechanisms of action, dosage effects, and dose duration remains limited. Previously, the dynamics of H₂ concentrations in different tissues of rats after exogenous H₂ inhalation had been detected by our team. Here, sequential changes of H₂ concentrations in different tissues of another most commonly used experimental rodent mice were monitored in real time with an electrochemical H₂ gas sensor during continuous different concentrations of H₂ inhalation targeting on five tissues including brain, liver, spleen, kidney, and gastrocnemius. The results showed that the H₂ saturation concentrations varied among tissues significantly regardless of the concentration of H₂ inhaled, and they were detected the highest in the kidney but the lowest in the gastrocnemius. Meantime, it required a significant longer time to saturate in the thigh muscle. By comparing the H₂ saturation concentrations of mice and rats, we found that there were no differences detected in most tissues except the kidney and spleen. Both gas diffusion and bloodstream transport could help the H₂ reach to most organs. The results provide data reference for dosage selection, dose duration determination to ensure optimal therapeutic effects of H₂ for mice experiments.

Chitin-glucan supplementation improved postprandial metabolism and altered gut microbiota in subjects at cardiometabolic risk in a randomized trial

Chitin-glucan (CG), an insoluble dietary fiber, has been shown to improve cardiometabolic disorders associated with obesity in mice. Its effects in healthy subjects has recently been studied, revealing its interaction with the gut microbiota. In this double-blind, randomized, cross-over, twice 3-week exploratory study, we investigated the impacts of CG on the cardiometabolic profile and gut microbiota composition and functions in 15 subjects at cardiometabolic risk. They consumed as a supplement 4.5 g of CG daily or maltodextrin as control. Before and after interventions, fasting and postprandial metabolic parameters and exhaled gases (hydrogen [H2] and methane [CH4]) were evaluated. Gut microbiota composition (16S rRNA gene sequencing analysis), fecal concentrations of bile acids, long- and short-chain fatty acids (LCFA, SCFA), zonulin, calprotectin and lipopolysaccharide binding protein (LBP) were analyzed. Compared to control, CG supplementation increased exhaled H2 following an enriched-fiber breakfast ingestion and decreased postprandial glycemia and triglyceridemia response to a standardized test meal challenge served at lunch. Of note, the decrease in postprandial glycemia was only observed in subjects with higher exhaled H2, assessed upon lactulose breath test performed at inclusion. CG decreased a family belonging to Actinobacteria phylum and increased 3 bacterial taxa: Erysipelotrichaceae UCG.003, Ruminococcaceae UCG.005 and Eubacterium ventriosum group. Fecal metabolites, inflammatory and intestinal permeability markers did not differ between groups. In conclusion, we showed that CG supplementation modified the gut microbiota composition and improved postprandial glycemic response, an early determinant of cardiometabolic risk. Our results also suggest breath H2 production as a non-invasive parameter of interest for predicting the effectiveness of dietary fiber intervention.

Different effects of hydrogen-rich water intake and hydrogen gas inhalation on gut microbiome and plasma metabolites of rats in health status

The potential for preventive and therapeutic applications of H₂ have now been confirmed in various disease. However, the effects of H₂ on health status have not been fully elucidated. Our previous study reported changes in the body weight and 13 serum biochemical parameters during the six-month hydrogen intervention. To obtain a more comprehensive understanding of the effects of long-term hydrogen consumption, the plasma metabolome and gut microbiota were investigated in this study. Compared with the control group, 14 and 10 differential metabolites (DMs) were identified in hydrogen-rich water (HRW) and hydrogen inhalation (HI) group, respectively. Pathway enrichment analysis showed that HRW intake mainly affected starch and sucrose metabolism, and DMs in HI group were mainly enriched in arginine biosynthesis. 16S rRNA gene sequencing showed that HRW intake induced significant changes in the structure of gut microbiota, while no marked bacterial community differences was observed in HI group. HRW intake mainly induced significant increase in the abundance of Lactobacillus, Ruminococcus, Clostridium XI, and decrease in Bacteroides. HI mainly induced decreased abundances of Blautia and Paraprevotella. The metabolic function was determined by metabolic cage analysis and showed that HI decreased the voluntary intake and excretions of rats, while HRW intake did not. The results of this study provide basic data for further research on hydrogen medicine. Determination of the effects of hydrogen intervention on microbiota profiles could also shed light on identification of mechanism underlying the biological effects of molecular hydrogen.

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.

The improvement of insulin level after hydrogen-rich water therapy in streptozotocin-induced diabetic rats

Background and Aim:

Water plays a pivotal role in the body. Alteration of the fluid balance promotes metabolic disorder, thus leading to the development of various diseases, such as diabetes mellitus (DM). Hydrogen-rich water (HW) is recognized as a novel antioxidant. This study aimed to investigate the role of HW on insulin, insulin receptor (IRs), and superoxide dismutase (SOD) levels in streptozotocin (STZ)-induced diabetic rats.

Materials and Methods:

A total of 30 male Wistar rats were randomly divided into five groups: Normal (N), DM rats, DM+metformin (DM+Met, 45 mg/kg body weight [BW]), DM+Met+HW, and DM+HW. DM rats were induced by feeding them a high-fat diet for 30 days and then injecting with repeated low doses of STZ (35 mg/kg BW) intraperitoneally. Fresh HW was administered orally and ad libitum for 14 days. Insulin, IRs, and SOD were observed in each group.

Results:

HW therapy increased the level and expression of insulin and IRs. In addition, treatment with HW also elevated the SOD levels in the serum and liver. The study results indicated no significant differences between the administration of HW and metformin.

Conclusion:

HW has antioxidant activity in STZ-induced DM rats, increasing insulin, IRs, and SOD.

Si-Based Hydrogen-Producing Nanoagent Protects Fetuses From Miscarriage Caused by Mother-to-Child Transmission

Mother-to-child transmission of viruses and bacteria increases the risk of miscarriage and various diseases in children. Such transmissions can result in infections and diseases in infants or the induction of an inflammatory immune response through the placenta. Recently, we developed a silicon (Si)-based hydrogen-producing nanoagent (Si-based agent) that continuously and effectively produces hydrogen in the body. Since medical hydrogen has antioxidative, anti-inflammatory, antiallergic, and antiapoptotic effects, we investigated the effects of our Si-based agent on mother-to-child transmission, with a focus on the rate of miscarriage. In pregnant mice fed a diet containing the Si-based agent, lipopolysaccharide (LPS)-induced miscarriage due to mother-to-child transmission was reduced and inflammation and neutrophil infiltration in the placenta were suppressed. We also found that the Si-based agent suppressed IL-6 expression in the placenta and induced the expression of antioxidant and antiapoptotic genes, such as Hmox1 and Ptgs2. The observed anti-inflammatory effects of the Si-based agent suggest that it may be an effective preventative or therapeutic drug for miscarriage or threatened miscarriage during pregnancy by suppressing maternal inflammation caused by bacterial and viral infections.

Pharmacokinetics of hydrogen after ingesting a hydrogen-rich solution: A study in pigs

Drinking hydrogen (H₂)-rich water is a common way to consume H₂. Although many studies have shown efficacy of drinking H₂-rich water in neuropsychiatric and endocrine metabolic disorders, their authenticity has been questioned because none examined the associated pharmacokinetics of H₂. Therefore, we performed the first study to investigate the pharmacokinetics of H₂ in pigs given an H₂-rich glucose solution with the aim to extrapolate the findings to humans. We inserted blood collection catheters into the jejunal and portal veins, suprahepatic inferior vena cava, and carotid artery of 4 female pigs aged 8 weeks. Then, within 2 min we infused 500 ml of either H₂-rich or H₂-free glucose solution into the jejunum via a percutaneous gastrostomy tube and measured changes in H₂ concentration in venous and arterial blood over 120 min. After infusion of the H₂-rich glucose solution, H₂ concentration in the portal vein peaked at 0.05 mg/L and remained at more than 0.016 mg/L (H₂ saturation level, 1%) after 1 h; it also increased after infusion of H₂-free glucose solution but remained below 0.001 mg/L (H₂ saturation level, 0.06%). We assume that H₂ was subsequently metabolized in the liver or eliminated via the lungs because it was not detected in the carotid artery. In conclusion, drinking highly concentrated H₂-rich solution within a short time is a good way to increase H₂ concentration in portal blood and supply H₂ to the liver.

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.

Effect of hydrogen-rich water on the lactic acid level in metformin-treated diabetic rats under hypoxia

The present study aims to investigate the impact of hydrogen-rich water on the lactic acid level in metformin-treated diabetic rats under hypoxia. Thirty Sprague-Dawley rats were randomly divided into five groups, including normal diet group, and diabetes model (DM) group, DM + metformin treatment (DMM) group, DMM + hypoxia treatment (DMMH) group and DMMH + hydrogenrich water (DMMHR) group. We found that the levels of lactic acid, pyruvate and lactate dehydrogenase were significantly lower in the blood of DMMHR group than DMMH group. Superoxide dismutase and glutathione levels in liver and heart were significantly higher in DMMH group after hydrogen-rich water treatment, while malondialdehyde and oxidized glutathione levels were decreased in DMMHR group when compared with DMMH group, which indicates that hydrogen-rich water could reduce oxidative stress. qPCR analysis demonstrated that that pro-apoptotic genes Bax/Caspase-3 were upregulated in DM group and metformin treatment suppressed their upregulation (DMM group). However, hypoxic condition reversed the effect of metformin on apoptotic gene expression, and hydrogen-rich water showed little effect on these genes under hypoxia. HE staining showed that hydrogen-rich water prevented myocardial fiber damages under hypoxia. In summary, we conclude that hydrogen-rich water could prevent lactate accumulation and reduce oxidant stress in diabetic rat model to prevent hypoxia-induced damages. It could be served as a potential agent for diabetes patients with metformin treatment to prevent lactic acidosis and reduce myocardial damages under hypoxic conditions.

The Search for the Elixir of Life: On the Therapeutic Potential of Alkaline Reduced Water in Metabolic Syndromes

Our body composition is enormously influenced by our lifestyle choices, which affect our health and longevity. Nutrition and physical activities both impact overall metabolic condition, thus, a positive energy balance causes oxidative stress and inflammation, hastening the development of metabolic syndrome. With this knowledge, boosting endogenous and exogenous antioxidants has emerged as a therapeutic strategy for combating metabolic disorders. One of the promising therapeutic inventions is the use of alkaline reduced water (ARW). Aside from its hydrating and non-caloric properties, ARW has demonstrated strong antioxidant and anti-inflammatory properties that can help stabilize physiologic turmoil caused by oxidative stress and inflammation. This review article is a synthesis of studies where we elaborate on the intra- and extracellular effects of drinking ARW, and relate these to the pathophysiology of common metabolic disorders, such as obesity, diabetes mellitus, non-alcoholic fatty liver disease, and some cancers. Highlighting the health-promoting benefits of ARW, we also emphasize the importance of maintaining a healthy lifestyle by incorporating exercise and practicing a balanced diet as forms of habit.

Nanocapsule-mediated sustained H2 release in the gut ameliorates metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is estimated to affect a quarter of all population and represents a major health threat to all societies. Yet, currently no approved pharmacological treatment is available for MAFLD. H₂-rich water has recently been reported to reduce hepatic lipid accumulation in MAFLD patients but its efficacy is limited due to low H₂ dosage. Increasing H₂ dose may enhance its therapeutic effects but remains technically challenging. In this study, we designed and synthesized a hydrogen nanocapsule by encapsulating ammonia borane into hollow mesoporous silica nanoparticles to achieve ultrahigh and sustained H₂ release in the gut. We then investigated its efficacy in treating early-stage MAFLD and other metabolic dysfunctions such as obesity and diabetes. The hydrogen nanocapsule attenuated both diet-induced and genetic mutation induced early-stage MAFLD, obesity, and diabetes in mice, without any tissue toxicity. Mechanistically, we discovered that sustained and ultrahigh H₂ supply by hydrogen nanocapsule increased, among other species, the abundance of Akkermansia muciniphila, highlighting reshaped gut microbiota as a potential mechanism of H₂ in treating metabolic dysfunctions. Moreover, hepatic transcriptome showed a reprogramed liver metabolism profile with reduced lipid synthesis and increased fatty acid metabolism.

Green Tea and Epigallocatechin Gallate (EGCG) for the Management of Nonalcoholic Fatty Liver Diseases (NAFLD): Insights into the Role of Oxidative Stress and Antioxidant Mechanism

Nonalcoholic fatty liver diseases (NAFLD) represent a set of liver disorders progressing from steatosis to steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma, which induce huge burden to human health. Many pathophysiological factors are considered to influence NAFLD in a parallel pattern, involving insulin resistance, oxidative stress, lipotoxicity, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory cascades, fibrogenic reaction, etc. However, the underlying mechanisms, including those that induce NAFLD development, have not been fully understood. Specifically, oxidative stress, mainly mediated by excessive accumulation of reactive oxygen species, has participated in the multiple NAFLD-related signaling by serving as an accelerator. Ameliorating oxidative stress and maintaining redox homeostasis may be a promising approach for the management of NAFLD. Green tea is one of the most important dietary resources of natural antioxidants, above which epigallocatechin gallate (EGCG) notably contributes to its antioxidative action. Accumulative evidence from randomized clinical trials, systematic reviews, and meta-analysis has revealed the beneficial functions of green tea and EGCG in preventing and managing NAFLD, with acceptable safety in the patients. Abundant animal and cellular studies have demonstrated that green tea and EGCG may protect against NAFLD initiation and development by alleviating oxidative stress and the related metabolism dysfunction, inflammation, fibrosis, and tumorigenesis. The targeted signaling pathways may include, but are not limited to, NRF2, AMPK, SIRT1, NF-κB, TLR4/MYD88, TGF-β/SMAD, and PI3K/Akt/FoxO1, etc. In this review, we thoroughly discuss the oxidative stress-related mechanisms involved in NAFLD development, as well as summarize the protective effects and underlying mechanisms of green tea and EGCG against NAFLD.

Higher Branched-chain Amino Acids and Lower Serine Exist in the Plasma of Nondiabetic Mice: A Comparison Between High- and Low-protein Diet Conditions

BACKGROUND/AIM

The effects of dietary protein and carbohydrate content on the plasma amino acid profile of patients with diabetes are not fully understood. Therefore, we examined whether there are effects of diets with differing proportions of protein and carbohydrate on the plasma amino acid concentrations of control (CT) mice and mice with type 2 diabetes (db).

MATERIALS AND METHODS

We used db mice as an animal model of type 2 diabetes which are genetically deficient in leptin receptor. Diets with differing proportions of protein and carbohydrates (L diet: low protein/carbohydrate ratio, H diet: high protein/carbohydrate ratio) were supplied. db Mice were fed with a restriction on the basis of the consumption by CT-L mice, such that equivalent amounts of energy and fat were consumed. In CT mice fed the L or H diets, there was no significant difference in ad libitum food intake.

RESULTS

There were significant interactions between diet and genotype with respect to water intake, urine volume, urinary glucose concentration, and plasma isoleucine, leucine, valine, branched-chain amino acids, and serine concentrations. db-H mice showed significantly higher water intake, urine volume, and urinary glucose than db-L mice. db Mice fed the L or H diets had similar plasma amino acid profiles, except for valine. In contrast, CT-H mice showed significantly higher valine and branched-chain amino acids and lower serine concentrations than CT-L mice. Thus, the CT-H mice were more similar to db mice fed either of the diets.

CONCLUSION

There were different effects of the dietary protein or carbohydrate content on the plasma amino acid profiles between nondiabetic and diabetic mice. In particular, the profiles in nondiabetic conditions were different between the low- and high-protein diet conditions.

Mechanisms Underlying the Biological Effects of Molecular Hydrogen

Aberrant redox-sensitive reactions and accumulation of oxidative damage can impair body functions and contribute to the development of various pathologies and aging. Although antioxidant substances have long been recognized as a measure of alleviating oxidative stress and restoring redox balance, the arsenal of effective means of preventing the development of various disorders, is still limited. There is an emerging field that utilizes molecular hydrogen (H₂) as a scavenger of free radicals and reactive oxygen species (ROS). Among the remarkable characteristics of H₂ is its ability to counteract the harmful effects of hydroxyl radical and peroxynitrite without affecting the activity of functionally important ROS, such as hydrogen peroxide and nitric oxide. The beneficial effects of H₂ have been documented in numerous clinical studies and studies on animal models and cell cultures. However, the established scavenging activity of H₂ can only partially explain its beneficial effects because the effects are achieved at very low concentrations of H₂. Given the rate of H₂ diffusion, such low concentrations may not be sufficient to scavenge continuously generated ROS. H₂ can also act as a signaling molecule and induce defense responses. However, the exact targets and mechanism(s) by which H₂ exerts these effects are unknown. Here, we analyzed both positive and negative effects of the endogenous H₂, identified the redox-sensitive components of the pathways affected by molecular hydrogen, and also discussed the potential role of molecular hydrogen in regulating cellular redox.

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 Commonly Applicable from Medicine to Agriculture: From Molecular Mechanisms to the Field

The emerging field of hydrogen biology has to date mainly been applied in medicine. However, hydrogen biology can also enable positive outcomes in agriculture. Agriculture faces significant challenges resulting from a growing population, climate change, natural disasters, environmental pollution, and food safety issues. In fact, hydrogen agriculture is a practical application of hydrogen biology, which may assist in addressing many of these challenges. It has been demonstrated that hydrogen gas (H₂) may enhance plant tolerance towards abiotic and biotic stresses, regulate plant growth and development, increase nutritional values, prolong the shelf life, and decrease the nitrite accumulation during the storage of vegetables, as well as increase the resilience of livestock to pathogens. Our field trials show that H₂ may have a promising potential to increase yield and improve the quality of agricultural products. This review aims to elucidate mechanisms for a novel agricultural application of H₂ in China. Future development of hydrogen agriculture is proposed as well. Obviously, hydrogen agriculture belongs to a low carbon economy, and has great potential to provide "safe, tasty, healthy, and high-yield" agricultural products so that it may improve the sustainability of agriculture.

Hydrogen Gas as an Exotic Performance-Enhancing Agent: Challenges and Opportunities

BACKGROUND

Hydrogen gas (H₂) has entered the world of experimental therapeutics approximately four and a half decades ago. Over the years, this simple molecule appears to drive more scientific attention, perhaps due to a dualism of H₂ affirmative features demonstrated in numerous in vitro, animal and human studies on one side, and still puzzling mechanism(s) of its biological activity on the other. Up to this point, H₂ was scrutinized for more than 170 different disease models and pathologies, and many research groups across the world have lately started to dynamically investigate its conceivable performance-enhancing potential.

METHODS

We outlined here the studies indexed in leading research databases (PubMed, Web of Science, SCOPUS, JSTORE) that explored the effects of hydrogen on exercise performance, and also addressed important restraints, open questions, and windows of opportunities for forthcoming research and possible H₂ enactment in exercise physiology. About two dozen trials have been identified in this domain, with most of the trials published during the past 5 years, while drinking hydrogen-rich water recognized as the most convenient method to deliver H₂ in both animal and human studies.

RESULTS

Either administered as an inhalational gas, enteral hydrogen-rich water, or intravenous hydrogen-rich saline, H₂ seems to favorably affect various exercise performance outcomes and biomarkers of exercise-associated fatigue, inflammation, and oxidative stress. Not all studies have shown corroborative effects, and it appears that the gold-standard protocol for applying H₂ in the field of exercise science does not exist at the moment, with studies markedly differ in the dose of H₂ administered, the duration of treatment, and the source of hydrogen.

CONCLUSION

H₂ is a newfangled and rather effective performance-enhancing agent, yet its promising ergogenic potency has to be further validated and characterized in more well-controlled, appropriately sampled and longterm mechanistic trials. Also, appropriate regulation of hydrogen utilization in sport as an exotic medical gas may require distinctive legislative actions of relevant regulatory agencies in the future.

Drinking Molecular Hydrogen Water Is Beneficial to Cardiovascular Function in Diet-Induced Obesity Mice

Molecular hydrogen (MH) reportedly exerts therapeutic effects against inflammatory diseases as a suppressor of free radical chain reactions. Here, the cardiovascular protective effects of the intake of molecular hydrogen water (MHW) were investigated using high-fat diet-induced obesity (DIO) mice. MHW was prepared using supplier sticks and degassed water as control. MHW intake for 2 weeks did not improve blood sugar or body weight but decreased heart weight in DIO mice. Moreover, MHW intake improved cardiac hypertrophy, shortened the width of cardiomyocytes, dilated the capillaries and arterioles, activated myocardial eNOS-Ser-1177 phosphorylation, and restored left ventricular function in DIO mice. MHW intake promoted the histological conversion of hypertrophy to hyperplasia in white and brown adipose tissues (WAT and BAT) with the upregulation of thermogenic and cardiovascular protective genes in BAT (i.e., Ucp-1, Vegf-a, and eNos). Furthermore, the results of a colony formation assay of bone-marrow-derived endothelial progenitor cells (EPCs) indicated that MHW activated the expansion, differentiation, and mobilization of EPCs to maintain vascular homeostasis. These findings indicate that the intake of MHW exerts cardiovascular protective effects in DIO mice. Hence, drinking MHW is a potential prophylactic strategy against cardiovascular disorders in metabolic syndrome.

The protective effect of hydrogen-rich water on rats with type 2 diabetes mellitus

The hydrogen-rich water (HW) has been reported to possess a beneficial role in patients with diabetes. However, a systemic evaluation with an appropriate animal model is necessary to reveal its mechanisms and efficacy. Herein, the protective effects of drinking HW on lipid and glucose metabolism, oxidative stress, and inflammation in type 2 diabetes mellitus (T2DM) rats were investigated. The well-modeled T2DM rats (induced by high-fat diet combined with low-dose streptozotocin (STZ) injection) were divided into two groups (n ≥ 15 of each): fed a high-fat diet and drinking distilled water or HW at a constant concentration above 1.0 ppm; normal rats were used as control group (n ≥ 10): fed a regular diet and drinking distilled water. Several biomarkers of lipid and glucose metabolism, oxidative stress ,and inflammation were evaluated after drinking distilled water or HW for 3 weeks. The effect of HW on liver, kidney, and spleen of T2DM rats was also analyzed by HE and Oil Red O staining. The results showed that drinking HW suppressed the increase in glucose, total cholesterol, oxidative stress, and inflammation. Moreover, HW also ameliorates hyperglycemia-induced liver, kidney, and spleen dysfunction. Overall, this study indicates that patients with T2DM may be able to improve their condition by supplementing HW as daily drinking water.

New Approaches for Hydrogen Therapy of Various Diseases

Hydrogen therapy has recently received increasing attention as an emerging and promising therapeutic technology due to its selective antioxidant property and cell energy regulatory capability in vivo. To solve the low solubility issue of hydrogen, a variety of nanomaterials and devices for hydrogen supply have recently been developed, aiming to increase the concentration of hydrogen in the specific disease site and realize controlled hydrogen release and combined treatment. In this review, we mainly focus on the latest advances in using hydrogen-generating devices and nanomaterials for hydrogen therapy. These developments include sustained release of H2, controlled release of H2, versatile modalities of synergistic therapy, etc. Also, bio-safety issues and challenges are discussed to further promote the clinical applications of hydrogen therapy and the development of hydrogen medicine.

Direct Targets and Subsequent Pathways for Molecular Hydrogen to Exert Multiple Functions: Focusing on Interventions in Radical Reactions

Molecular hydrogen (H₂) was long regarded as non-functional in mammalian cells. We overturned the concept by demonstrating that H₂ exhibits antioxidant effects and protects cells against oxidative stress. Subsequently, it has been revealed that H₂ has multiple functions in addition to antioxidant effects, including antiinflammatory, anti-allergic functions, and as cell death and autophagy regulation. Additionally, H₂ stimulates energy metabolism. As H₂ does not readily react with most biomolecules without a catalyst, it is essential to identify the primary targets with which H₂ reacts or interacts directly. As a first event, H₂ may react directly with strong oxidants, such as hydroxyl radicals (•OH) in vivo. This review addresses the key issues related to this in vivo reaction. •OH may have a physiological role because it triggers a free radical chain reaction and may be involved in the regulation of Ca2+- or mitochondrial ATP-dependent K+-channeling. In the subsequent pathway, H₂ suppressed a free radical chain reaction, leading to decreases in lipid peroxide and its end products. Derived from the peroxides, 4-hydroxy-2-nonenal functions as a mediator that up-regulates multiple functional PGC-1α. As the other direct target in vitro and in vivo, H₂ intervenes in the free radical chain reaction to modify oxidized phospholipids, which may act as an antagonist of Ca2+-channels. The resulting suppression of Ca2+-signaling inactivates multiple functional NFAT and CREB transcription factors, which may explain H₂ multi-functionality. This review also addresses the involvement of NFAT in the beneficial role of H₂ in COVID-19, Alzheimer's disease and advanced cancer. We discuss some unsolved issues of H₂ action on lipopolysaccharide signaling, MAPK and NF-κB pathways and the Nrf2 paradox. Finally, as a novel idea for the direct targeting of H2, this review introduces the possibility that H₂ causes structural changes in proteins via hydrate water changes.

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.

Two-week continuous supplementation of hydrogenrich water increases peak oxygen uptake during an incremental cycling exercise test in healthy humans: a randomized, single-blinded, placebo-controlled study

The various beneficial effects of the intake of molecular hydrogen (H2) have been demonstrated in the field of sports science. Although supplementation of H2 has been reported to increase mitochondrial metabolism in animal studies, the effects of the administration of H2 on aerobic capacity during exercise in humans are still not clear. We investigated whether a single or 2-week continuous intake of H2-rich water (HW) enhanced the aerobic capacity during incremental exercise in healthy humans. In this randomized, single-blinded, placebo-controlled experimental study, the participants performed an incremental cycling exercise to measure peak oxygen uptake and peak load before and after a single (500 mL) or a 2-week supplementation (total 5 L) of HW. In the latter experiment, the participants drank the 500 mL of HW on all weekdays (i.e., 10 times). The single intake of HW did not significantly increase peak oxygen uptake and peak load, and did not significantly alter the responses in oxidative stress, antioxidant activity, and lactate levels. However, importantly, the 2-week continuous consumption of HW significantly augmented peak oxygen uptake and tended to increase the peak load without any significant changes in lactate levels, oxidative stress, and antioxidant responses. In conclusion, the continuous supplementation of HW potentially augments the aerobic capacity, implying that continuous supplementation of H2 might help improve aerobic exercise performance and physical health. This study protocol was approved by the Ethical Committee of Chubu University (approval No. 260086-2) on March 29, 2018.

Hydrogen influences HDL-associated enzymes and reduces oxidized phospholipids levels in rats fed with a high-fat diet

AIMS

Oxidized phospholipids (OxPLs) are formed as a result of oxidative stress, which potentially mediate multiple pathological effects. We aimed to evaluate the effects of hydrogen (H₂) on OxPLs in vivo and the underlying mechanism.

MAIN METHODS

Rats were randomly assigned to three groups: control group fed with a chow diet, model group fed with a high-fat diet, and H₂-treated group fed with a high-fat diet and treated by 4% H₂ inhalation for ten weeks. OxPLs in liver and plasma were analyzed by liquid chromatography-mass spectrometry. High-density lipoprotein (HDL) was separated by ultracentrifugation. A proteomic analysis was performed to reveal the alternation of HDL protein composition and he antioxidant capacity of HDL was tested by low-density lipoprotein oxidation experiment. Furthermore, the activity or expression of HDL-associated enzymes were evaluated.

KEY FINDINGS

Inhalation of 4% H₂ decreased the accumulation of OxPLs in rats. In vitro tests revealed that the different concentrations of H₂ did not inhibit the formation of OxPLs mediated by non-enzymatic oxidation. H₂ inhalation altered the components and enhanced the anti-oxidative capacity of HDL in rats fed with a high-fat diet. Further experiments showed that H₂ significantly regulated the activity of lipoprotein-associated phospholipase A₂, paraoxonase-1, and the expression of lecithin:cholesterol acyltransferase.

SIGNIFICANCE

Our findings revealed that H₂ may reduce the OxPLs levels through its influence on HDL-associated enzymes that can act on OxPLs, suggesting that H₂ can be used in alleviating diseases related to lipid peroxidation due to oxidative stress.

Effects of long-term hydrogen intervention on the physiological function of rats

The potential therapeutic effects of molecular hydrogen (H₂) have now been confirmed in various human and animal-disease models. However, the effects of H₂ on the physiological function in a normal state have been largely neglected. Hydrogen-rich water (HRW) intake and hydrogen inhalation (HI) are the most common used methods for hydrogen administration, the difference in the effects between HRW intake and HI remains elusive. In the present study, the body weight and 13 serum biochemical parameters were monitored during the six-month hydrogen intervention, all these parameters were significantly altered by oral intake of HRW or HI. Among the 13 parameters, the most striking alterations induced by hydrogen treatment were observed in serum myocardial enzymes spectrum. The results also showed that the changes in these parameters occurred at different time points, and the alterations in most of the parameters were much more significant in HI than HRW. The results of this study provides the basic data for the mechanism research and application of molecular hydrogen in the future.

Protective Mechanism and Clinical Application of Hydrogen in Myocardial Ischemia-reperfusion Injury

Cardiovascular disease accounts for one-third of all deaths, with ischemic heart disease as the main cause of death. Under pathological conditions, ischemia-reperfusion injury (IRI) often occurs in tissues. Ischemic injury is mainly caused by anaerobic cell death and reperfusion which results in a wide range of inflammatory responses. These responses are able to increase tissue damage and even damage to the whole body. IRI can also aggravate the original cardiovascular disease during the treatment of cardiovascular disease. Therefore, it is particularly important to understand the mechanism of myocardial ischemia-reperfusion injury (MIRI) for clinical treatment and application. At the same time, it is necessary to find a safe, reliable and feasible method for treating MIRI to reduce the incidence of complications and mortality as well as improve the prognosis and quality of life of patients. As a selective antioxidant, hydrogen can neutralize excessive free radicals, has certain anti-apoptotic and anti-inflammatory effects and it has gradually become a focus and hotspot of preclinical and clinical research. Hydrogen has been shown to have a certain therapeutic effect on MIRI, which can provide a new therapeutic direction for the clinical treatment of myocardial ischemia-reperfusion injury. In this review, the protective mechanism and clinical application of hydrogen in myocardial ischemia-reperfusion injury is discussed.

Inhalation of molecular hydrogen increases breath acetone excretion during submaximal exercise: a randomized, single-blinded, placebo-controlled study

Aerobic exercise is widely accepted as a beneficial option for reducing fat in humans. Recently, it has been suggested that molecular hydrogen (H₂) augments mitochondrial oxidative phosphorylation. Therefore, the hypothesis that inhaling H₂ could facilitate lipid metabolism during aerobic exercise was investigated in the current study by measuring the breath acetone levels, which could be used as non-invasive indicators of lipid metabolism. This study aimed to investigate the effect of inhaling H₂ on breath acetone output during submaximal exercise using a randomized, single-blinded, placebo-controlled, and cross-over experimental design. After taking a 20-minute baseline measurement, breath acetone levels were measured in ten male subjects who performed a 60% peak oxygen uptake-intensity cycling exercise for 20 minutes while inhaling either 1% H₂ or a control gas. In another experiment, six male subjects remained in a sitting position for 45 minutes while inhaling either 1% H₂ or a control gas. H₂ significantly augmented breath acetone and enhanced oxygen uptake during exercise (P < 0.01). However, it did not significantly change oxidative stress or antioxidant activity responses to exercise, nor did it significantly alter the breath acetone or oxygen uptake during prolonged resting states. These results suggest that inhaling H₂ gas promotes an exercise-induced increase in hepatic lipid metabolism. The study was approved by the Ethical Committee of Chubu University, Japan (approved No. 260086-2) on March 29, 2018.