Molecular hydrogen stabilizes atherosclerotic plaque in low-density lipoprotein receptor-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.

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.

Controlled Release of Hydrogen-Carrying Perfluorocarbons for Ischemia Myocardium-Targeting 19 F MRI-Guided Reperfusion Injury Therapy

Hydrogen gas is recently proven to have anti-oxidative and anti-inflammation effects on ischemia-reperfusion injury. However, the efficacy of hydrogen therapy is limited by the efficiency of hydrogen storage, targeted delivery, and controlled release. In this study, H2 -PFOB nanoemulsions (NEs) is developed with high hydrogen loading capacity for targeted ischemic myocardium precision therapy. The hydrogen-carrying capacity of H2 -PFOB NEs is determined by gas chromatography and microelectrode methods. Positive uptake of H2 -PFOB NEs in ischemia-reperfusion myocardium and the influence of hydrogen on 19 F-MR signal are quantitatively visualized using a 9.4T MR imaging system. The biological therapeutic effects of H2 -PFOB NEs are examined on a myocardial ischemia-reperfusion injury mouse model. The results illustrated that the developed H2 -PFOB NEs can efficaciously achieve specific infiltration into ischemic myocardium and exhibit excellent antioxidant and anti-inflammatory properties on myocardial ischemia-reperfusion injury, which can be dynamically visualized by 19 F-MR imaging system. Moreover, hydrogen burst release induced by low-intensity focused ultrasound (LIFU) irradiation further promotes the therapeutic effect of H2 -PFOB NEs with a favorable biosafety profile. In this study, the potential therapeutic effects of H2 -PFOB NEs is fully unfolded, which may hold great potential for future hydrogen-based precision therapeutic applications tailored to ischemia-reperfusion injury.

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.

Hydrogen Intake Relieves Alcohol Consumption and Hangover Symptoms in Healthy Adults: a Randomized and Placebo-Controlled Crossover Study

BACKGROUND

Alcohol-induced hangover represents a significant, yet understudied, global hazard and a large socio-economic burden.

OBJECTIVES

The aim of this study was to investigate the effects of hydrogen (H2) on relieving drinking and hangover symptoms in 20 healthy volunteers.

METHODS

In this pilot, randomized, double-blinded, placebo-controlled, matched, crossover interventional trial, participants were matched into pairs and randomly assigned. Study group 1 inhaled placebo air for 1 hr, followed by drinking 100 ml of liquor (40% alcohol) within 10 min, and then pure water. Study group 2 inhaled a mixture of H2 and O2 gas for 1 hr, followed by drinking 100 ml of liquor within 10 min, and then H2 dissolved in water. On a second intervention day (crossover) ≥1 wk later, study-group subjects were switched to the opposite order. Breath alcohol concentration (BrAC), hangover severity, and cognitive scores were measured.

RESULTS

The BrACs within the H2 group were significantly lower than those within the placebo group after 30 min, 60 min, and 90 min (P < 0.05). The H2 group reported having fewer hangover symptoms compared with the placebo group (Placebo: 77% of symptoms absent, 19.7% of mild symptoms, 2.7% of moderate symptoms, 0.7% of severe symptoms; H2: 88.6% of symptoms absent, 10% of mild symptoms, 1.3% of moderate symptoms, 0% of severe symptoms; P < 0.001). H2 treatment improved cognitive testing scores (P < 0.05), including attention and executive functions. Furthermore, consumption of H2 was negatively (β = -13.016; 95% CI: -17.726, -8.305; P < 0.001) and female sex was positively (β = 22.611; 95% CI: 16.226, 28.997; P < 0.001) correlated with increased BrACs. Likewise, the consumption of H2 was negatively (OR: 0.035; 95% CI: 0.007, 0.168; P < 0.001) while female sex was positively (OR: 28.838; 95% CI: 5.961, 139.506; P < 0.001) correlated with the severity of hangover symptoms.

CONCLUSIONS

H2 decreases BrACs and relieves the symptoms of hangovers.This trial was registered at China Clinical Trial Registry as ChiCTR2200059988. URL of registration: http://www.chictr.org.cn/showproj.aspx?proj=58359.

N-acetylcysteine attenuates atherosclerosis progression in aging LDL receptor deficient mice with preserved M2 macrophages and increased CD146

BACKGROUND AND AIMS

Inflammation and reactive oxygen species (ROS) are important to the pathogenesis of atherosclerosis. The effect of antioxidants on atherosclerosis is inconsistent, and sometimes controversial. We aimed to test the hypothesis that attenuation of atherosclerosis by N-acetylcysteine (NAC) depends on NAC treatment timing and duration.

METHODS

Male LDL receptor deficient (LDLR^-/-) mice were fed a normal diet (ND) and divided into controls (on ND for 24 months), models 1-2 (at age of 9 months, starting NAC treatment for 3 or 6 months), and model 3 (at age of 18 months, starting NAC treatment for 6 months). To determine if hyperlipidemia compromises NAC treatment outcome, mice were fed a high fat diet (HFD) starting at age of 6 weeks and treated with NAC starting at 9 months of age for 6 months.

RESULTS

NAC treatment for 6 months, not for 3 months, significantly attenuated atherosclerosis progression, but did not reverse atherosclerotic lesions, in aging LDLR^-/- mice on ND. NAC had no effect on atherosclerotic lesions in mice on HFD. NAC treatment significantly decreased aortic ROS production, and the levels of inflammatory cytokines in serum and aorta of aging LDLR^-/- mice with increased CD146 level. Bone marrow transplantation study with GFP-positive bone marrow cells showed that NAC treatment preserved M2 population and M2 polarization in the aorta of LDLR^-/- mice.

CONCLUSIONS

Early and adequate NAC treatment could effectively attenuate inflammation and atherosclerosis progression with preserved M2 population and increased CD146 level in aging LDLR^-/- mice without extreme hyperlipidemia.

Molecular Hydrogen Inhibits Colorectal Cancer Growth via the AKT/SCD1 Signaling Pathway

Objective

Molecular hydrogen (H₂) has been considered a potential therapeutic target in many cancers. Therefore, we sought to assess the potential effect of H₂ on colorectal cancer (CRC) in this study.

Methods

The effect of H₂ on the proliferation and apoptosis of RKO, SW480, and HCT116 CRC cell lines was assayed by CCK-8, colony formation, and flow cytometry assays. The effect of H₂ on tumor growth was observed in xenograft implantation models (inhalation of 67% hydrogen two hours per day). Western blot and immunohistochemistry analyses were performed to examine the expression of p-PI3K, PI3K, AKT, pAKT, and SCD1 in CRC cell lines and xenograft mouse models. The expression of SCD1 in 491 formalin-fixed, paraffin-embedded CRC specimens was investigated with immunochemistry. The relationship between SCD1 status and clinicopathological characteristics and outcomes was determined.

Results

Hydrogen treatment suppressed the proliferation of CRC cell lines independent of apoptosis, and the cell lines showed different responses to different doses of H₂. Hydrogen also elicited a potent antitumor effect to reduce CRC tumor volume and weight in vivo. Western blot and IHC staining demonstrated that H₂ inhibits CRC cell proliferation by decreasing pAKT/SCD1 levels, and the inhibition of cell proliferation induced by H₂ was reversed by the AKT activator SC79. IHC showed that SCD1 expression was significantly higher in CRC tissues than in normal epithelial tissues (70.3% vs. 29.7%, p = 0.02) and was correlated with a more advanced TNM stage (III vs. I + II; 75.9% vs. 66.3%, p = 0.02), lymph node metastasis (with vs. without; 75.9% vs. 66.3%, p = 0.02), and patients without a family history of CRC (78.7% vs. 62.1%, p = 0.047).

Conclusion

This study demonstrates that high concentrations of H₂ exert an inhibitory effect on CRC by inhibiting the pAKT/SCD1 pathway. Further studies are warranted for clinical evaluation of H₂ as SCD1 inhibitor to target CRC.

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.

Protective Effect of Molecular Hydrogen Following Different Routes of Administration on D-Galactose-Induced Aging Mice

Background

Molecular hydrogen (H₂) has been recognized as an effective antioxidant with no or little side effects. While it is known that oxidative stress is closely associated with aging, the beneficial effect of H₂ on oxidative stress-related aging is still unclear. In this study, a mouse model of D-galactose-induced aging was employed to investigate the protective effects of H₂.

Methods

The mice were administrated of H₂ via different routes (4% H₂ inhalation, H₂-rich water drinking, and H₂-rich saline injection), the aging-related biomarkers in plasma and the oxidative stress in different tissues were measured.

Results

The results showed that H₂ improved aging-related biomarkers, ie, total antioxidant capacity, advanced glycation end products, tumor necrosis factor-α, free fatty acids, and alanine aminotransferase in plasma. Furthermore, H₂ alleviated oxidative stress in the liver, brain, and heart by reducing the levels of lipid peroxidation and malondialdehyde and increasing the activity of superoxide dismutase. In addition, it seems that 4% H₂ inhalation was the most effective regarding the amount of H₂ taken up and in reducing the markers of oxidative stress in some of the tissues; however, the other routes of administration resulted in the same efficacy in most indicators.

Conclusion

H₂ can prevent oxidative stress in D-galactose-induced aging mice when administered by different routes.

Hydrogen alleviates acute lung injury induced by limb ischaemia/reperfusion in mice

AIMS

Limb ischaemia/reperfusion (LIR) occurs in various clinical conditions including critical limb ischaemia, abdominal aortic aneurysm, and traumatic arterial injury. Reperfusion of the acutely ischemic limb can lead to a systemic inflammation response and multiple organ dysfunction syndrome, further resulting in significant morbidity and mortality. Molecular hydrogen exhibits therapeutic activity for the treatment and prevention of many diseases. Our study investigated the possible therapeutic effects of hydrogen and its mechanism of action in a LIR-induced acute lung injury (ALI) model.

MATERIALS AND METHODS

Limb ischaemia/-reperfusion model was established in mice. The hydrogen-saturated saline was administered by intraperitoneal injection. Protein level of nuclear factor erythroid 2-related factor 2 (Nrf2), haem oxygenase-1 (HO1) and nicotinamide adenine dinucleotide phosphate quinone oxidoreductase 1 (NQO1) was evaluated by immunohistochemistry staining and western blotting. Autophagy-related molecules were evaluated by western blotting. Malondialdehyde (MDA) and superoxide dismutase (SOD) were determined by assay kits. Quantification of ceramides in lung was performed by high-performance liquid chromatography-tandem mass spectrometry.

KEY FINDINGS

Molecular hydrogen exhibited a protective effect on the LIR-induced ALI model. Hydrogen decreased malondialdehyde and increased superoxide dismutase activity in lung tissues. Additionally, hydrogen activated Nrf2 signalling in lung tissues. Hydrogen could inhibit the upregulation of autophagy in the present rodent model. Furthermore, ceramide was accumulated in lung tissues because of LIR; however, hydrogen altered the accumulation status.

SIGNIFICANCE

Molecular hydrogen was found to be therapeutically effective in the LIR-induced ALI model; the mechanisms of action included modulation of antioxidation and autophagy.

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.

Secreted frizzled-related protein 4 promotes brown adipocyte differentiation

Secreted frizzled-related protein 4 (SFRP4) is a member of the SFRP family that contains a cysteine-rich domain homologous to the putative Wnt-binding site of frizzled proteins. In the present report, the effects of SFRP4 on murine brown adipocyte differentiation were evaluated, which exhibited an intrinsic capacity to differentiate with high efficiency. Brown preadipocytes were isolated from the scapular region of brown adipose tissue, which showed that the overexpression of recombinant active SFRP4 protein at three concentrations (1, 10 and 100 ng/ml) significantly increased the expression of adipocyte differentiation-associated genes (C/EBPα, C/EBPβ, UCP-1, PRDM16, PGC1α and GLUT4) in a dose-dependent manner compared with the control group. Secondly, adiponectin protein expression was significantly inhibited in a dose-independent manner, while leptin was increased in brown adipocytes by incubation with the high concentration (100 ng/ml) of SFRP4. Thirdly, the role of interleukin-1β (IL-1β) was investigated in brown adipocytes and discovered that IL-1β cannot induce SFRP4 mRNA expression in brown adipocytes, similar to human islet cells. These data suggested that SFRP4-treated brown adipocytes represent a valuable in vitro model for the study of adipogenesis and indicated that SFRP4 served various functions during brown adipocyte differentiation.

Hydrogen-saturated saline mediated neuroprotection through autophagy via PI3K/AKT/mTOR pathway in early and medium stages of rotenone-induced Parkinson's disease rats

Some cardiovascular symptoms in the early stage of Parkinson's disease (PD) were related to degeneration of the rostral ventrolateral medulla (RVLM) catecholaminergic neurons. To date, little is known about the effects of hydrogen water on early stage of PD. Here, protective actions of hydrogen-saturated saline (HS) on rotenone-induced PD rats, as well as its underlying mechanisms were investigated. HS was used to treat PD rats at three general stages; early, medium and late, which were represented by rotenone induced rats for 0, 7 and 14 days. HS treatment significantly alleviated the cardiovascular and motor symptoms in rotenone-induced PD rats, improved the survival number of RVLM catecholaminergic neurons and nigral dopamine neurons only in early and medium stages of PD rats. Decreased levels of reactive oxygen species (ROS) and alpha-synuclein (α-Syn), transformation of microtubule associated protein 1 light chain 3 (LC3)-I/II and degradation of sequestosome 1 (p62) were detected, as well as increased expression level of autophagy related protein 5 (ATG5) and B-cell lymphoma-2 interacting protein 1 (Beclin-1) in the RVLM and substantia nigra (SN) after HS treatment in early and medium stages of PD rats. In addition, phosphorylation levels of phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) and mammalian rapamycin target protein (mTOR) decreased after HS treatment in early and medium stages of PD rats. The results suggested that HS treatment exerted beneficial effects in early and medium stages before motor impairments emerged but not in the late stage of rotenone-induced PD rats. It exerted neuroprotection with RVLM catecholaminergic neurons and nigral dopamine neurons, mediated in part by decreasing levels of ROS and α-Syn through increasing autophagy machinery which were partly via inhibiting PI3K-Akt-mTOR pathway.

Hydrogen and therapeutic gases for neonatal hypoxic-ischemic encephalopathy: potential neuroprotective adjuncts in translational research

Numerous studies have examined the potential use of therapeutic gases for the treatment of various neurological disorders. Hydrogen gas, a promising neuroprotective agent, has been a focus of study due to its potent antioxidative properties. In translational research into adult diseases, hydrogen has been shown to be neuroprotective in disorders such as cerebral ischemia and traumatic brain injury, and in neurodegenerative diseases such as Alzheimer's disease. Animal and human studies have verified the safety and feasibility of molecular hydrogen. However, despite extensive research on its efficacy in adults, only a few studies have investigated its application in pediatric and neonatal medicine. Neonatal hypoxic-ischemic encephalopathy (HIE) is characterized by damage to neurons and other cells of the nervous system. One of the major contributing factors is excessive exposure to oxidative stress. Current research interest in HIE is shifting toward new neuroprotective agents, as single agents or as adjuncts to therapeutic hypothermia. Here, we review therapeutic gases, particularly hydrogen, and their potentials and limitations in the treatment of HIE in newborns. IMPACT: Translational animal models of neonatal HIE are a current focus of research into the therapeutic usefulness of various gases. Hydrogen ventilation as a single agent or in combination with therapeutic hypothermia shows short- and long-term neuroprotection in neonatal translational HIE models. The optimal target severity for therapeutic interventions should be well established to improve outcomes.

Molecular hydrogen: A potential radioprotective agent

In recent years, many studies have shown that hydrogen has therapeutic and preventive effects on various diseases. Its selective antioxidant properties were well noticed. Most of the ionizing radiation-induced damage is caused by hydroxyl radicals (OH) from radiolysis of H₂O. Since hydrogen can mitigate such damage through multiple mechanisms, it presents noteworthy potential as a novel radio-protective agent. This review analyses possible mechanisms for hydrogen's radioprotective properties and effective delivery methods. We also look into details of vitro and vivo studies for hydrogen's radioprotective effects, and clinical practices. We conclude that hydrogen has good potential in radio-protection, with evidence that warrants greater research efforts in this field.

Hydrogen inhalation alleviates nonalcoholic fatty liver disease in metabolic syndrome rats

Hydrogen exhibits therapeutic and preventive effects against various diseases. The present study investigated the potential protective effect and dose-dependent manner of hydrogen inhalation on high fat and fructose diet (HFFD)-induced nonalcoholic fatty liver disease (NAFLD) in Sprague-Dawley rats. Rats were randomly divided into four groups: i) Control group, regular diet/air inhalation; ii) model group, HFFD/air inhalation; iii) low hydrogen group, HFFD/4% hydrogen inhalation; and iv) high hydrogen group, HFFD/67% hydrogen inhalation. After a 10-week experiment, hydrogen inhalation ameliorated weight gain, abdominal fat index, liver index and body mass index of rats fed with HFFD and lowered the total area under the curve in an oral glucose tolerance test. Hydrogen inhalation also ameliorated the increase in liver lipid content and alanine transaminase and aspartate transaminase activities. Liver histopathologic changes evaluated with hematoxylin and eosin as well as Oil Red O staining revealed lower lipid deposition in hydrogen inhalation groups, consistent with the decrease in the expression of the lipid synthesis gene SREBP-1c. The majority of the indicators were affected following treatment with hydrogen in a dose-dependent manner. In conclusion, hydrogen inhalation may play a protective role by influencing the general state, lipid metabolism parameters, liver histology and liver function indicators in the rat model of metabolic syndrome with NAFLD.

Molecular hydrogen: current knowledge on mechanism in alleviating free radical damage and diseases

Ever since molecular hydrogen was first reported as a hydroxyl radical scavenger in 2007, the beneficial effect of hydrogen was documented in more than 170 disease models and human diseases including ischemia/reperfusion injury, metabolic syndrome, inflammation, and cancer. All these pathological damages are concomitant with overproduction of reactive oxygen species (ROS) where molecular hydrogen has been widely demonstrated as a selective antioxidant. Although it is difficult to construe the molecular mechanism of hydrogen's biomedical effect, an increasing number of studies have been helping us draw the picture clearer with days passing by. In this review, we summarized the current knowledge on systemic and cellular modulation by hydrogen treatment. We discussed the antioxidative, anti-inflammatory, and anti-apoptosis effects of hydrogen, as well as its protection on mitochondria and the endoplasmic reticulum, regulation of intracellular signaling pathways, and balancing of the immune cell subtypes. We hope that this review will provide organized information that prompts further investigation for in-depth studies of hydrogen effect.

Regulatory T cells: Possible mediators for the anti-inflammatory action of statins

Statins beside their main effect on reducing the progression of cardiovascular disease through pharmacological inhibition of the endogenous cholesterol synthesis, have additional pleiotropic effects including antiinflammatory effects mediated through the induction of suppressor regulatory T cells (Tregs). Statin-induced expansion of Tregs reduces chronic inflammation and may have beneficial effects in autoimmune diseases. However, statins could represent a double-edged sword in immunomodulation. Drugs that act by increasing the concentration of Tregs could enhance the risk of cancers, particularly in the elderly and may have adverse effects in neurodegenerative disorders and infectious diseases. In the present paper, we review the experimental studies that evaluate the effects of statins on Treg cells in autoimmune and inflammatory diseases and we discuss potential therapeutic applications of statins in this setting.

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.

Inhalation of hydrogen gas elevates urinary 8-hydroxy-2'-deoxyguanine in Parkinson's disease

Hyposmia is one of the earliest and the most common symptoms in Parkinson's disease (PD). The benefits of hydrogen water on motor deficits have been reported in animal PD models and PD patients, but the effects of hydrogen gas on PD patients have not been studied. We evaluated the effect of inhalation of hydrogen gas on olfactory function, non-motor symptoms, activities of daily living, and urinary 8-hydroxy-2'-deoxyguanine (8-OHdG) levels by a randomized, double-blinded, placebo-controlled, crossover trial with an 8-week washout period in 20 patients with PD. Patients inhaled either ~1.2-1.4% hydrogen-air mixture or placebo for 10 minutes twice a day for 4 weeks. Inhalation of low dose hydrogen did not significantly influence the PD clinical parameters, but it did increase urinary 8-OHdG levels by 16%. This increase in 8-OHdG is markedly less than the over 300% increase in diabetes, and is more comparable to the increase after a bout of strenuous exercise. Although increased reactive oxygen species is often associated with toxicity and disease, they also play essential roles in mediating cytoprotective cellular adaptations in a process known as hormesis. Increases of oxidative stress by hydrogen have been previously reported, along with its ability to activate the Nrf2, NF-κB pathways, and heat shock responses. Although we did not observe any beneficial effect of hydrogen in our short trial, we propose that the increased 8-OHdG and other reported stress responses from hydrogen may indicate that its beneficial effects are partly or largely mediated by hormetic mechanisms. The study was approved by the ethics review committee of Nagoya University Graduate School of Medicine (approval number 2015-0295). The clinical trial was registered at the University Hospital Medical Information Network (identifier UMIN000019082).

Quantification of hydrogen production by intestinal bacteria that are specifically dysregulated in Parkinson's disease

Oral administration of hydrogen water ameliorates Parkinson’s disease (PD) in rats, mice, and humans. We previously reported that the number of putative hydrogen-producing bacteria in intestinal microbiota is low in PD compared to controls. We also reported that the amount of hydrogen produced by ingestion of lactulose is low in PD patients. The decreased hydrogen production by intestinal microbiota may be associated with the development and progression of PD. We measured the amount of hydrogen production using gas chromatography by seven bacterial strains, which represented seven major intestinal bacterial groups/genera/species. Blautia coccoides and Clostridium leptum produced the largest amount of hydrogen. Escherichia coli and Bacteroides fragilis constituted the second group that produced hydrogen 34- to 93-fold lower than B. coccoides. Bifidobacterium pseudocatenulatum and Atopobium parvulum constituted the third group that produced hydrogen 559- to 2164-fold lower than B. coccoides. Lactobacillus casei produced no detectable hydrogen. Assuming that taxonomically neighboring strains have similar hydrogen production, we simulated hydrogen production using intestinal microbiota that we previously reported, and found that PD patients produce a 2.2-fold lower amount of intestinal hydrogen compared to controls. The lower amount of intestinal hydrogen production in PD was also simulated in cohorts of two other countries. The number of hydrogen-producing intestinal bacteria may be associated with the development and progression of PD. Further studies are required to prove its beneficial effect.

Electrochemically Reduced Water Delays Mammary Tumors Growth in Mice and Inhibits Breast Cancer Cells Survival In Vitro

Electrochemical reduced water (ERW) has been proposed to have beneficial effects on human health due to its rich content of H₂ and the presence of platinum nanoparticles with antioxidant effects. Many studies have demonstrated that ERW scavenging properties are able to reduce the damage caused by oxidative stress in different experimental models. Although few in vivo studies have been reported, it has been demonstrated that ERW may display anticancer effects by induction of tumor cells apoptosis and reduction of both angiogenesis and inflammation. In this study, we show that ERW treatment of MCF-7, MDA-MB-453, and mouse (TUBO) breast cancer cells inhibited cell survival in a time-dependent fashion. ERW decreased ErbB2/neu expression and impaired pERK1/ERK2 and AKT phosphorylation in breast cancer cells. In addition, ERW treatment induced apoptosis of breast cancer cell lines independently of the status of p53 and ER and PR receptors. Our in vivo results showed that ERW treatment of transgenic BALB-neuT mice delayed the development of mammary tumors compared to the control. In addition, ERW induced a significant prolongation of tumor-free survival and a reduction in tumor multiplicity. Overall, these results suggest a potential beneficial role of ERW in inhibiting cancer cells growth.

Inhalation of Hydrogen Attenuates Progression of Chronic Heart Failure via Suppression of Oxidative Stress and P53 Related to Apoptosis Pathway in Rats

Background: Continuous damage from oxidative stress and apoptosis are the important mechanisms that facilitate chronic heart failure (CHF). Molecular hydrogen (H₂) has potentiality in the aspects of anti-oxidation. The objectives of this study were to investigate the possible mechanism of H₂ inhalation in delaying the progress of CHF.

Methods and Results: A total of 60 Sprague-Dawley (SD) rats were randomly divided into four groups: Sham, Sham treated with H₂, CHF and CHF treated with H₂. Rats from CHF and CHF treated with H₂ groups were injected isoprenaline subcutaneously to establish the rat CHF model. One month later, the rat with CHF was identified by the echocardiography. After inhalation of H₂, cardiac function was improved vs. CHF (p < 0.05), whereas oxidative stress damage and apoptosis were significantly attenuated (p < 0.05). In this study, the mild oxidative stress was induced in primary cardiomyocytes of rats, and H₂ treatments significantly reduced oxidative stress damage and apoptosis in cardiomyocytes (p < 0.05 or p < 0.01). Finally, as a pivotal transcription factor in reactive oxygen species (ROS)-apoptosis signaling pathway, the expression and phosphorylation of p53 were significantly reduced by H₂ treatment in this rat model and H9c2 cells (p < 0.05 or p < 0.01).

Conclusion: As a safe antioxidant, molecular hydrogen mitigates the progression of CHF via inhibiting apoptosis modulated by p53. Therefore, from the translational point of view and speculation, H₂ is equipped with potential therapeutic application as a novel antioxidant in protecting CHF in the future.

Hydrogen gas inhalation protects against cutaneous ischaemia/reperfusion injury in a mouse model of pressure ulcer

Pressure ulcer formation depends on various factors among which repetitive ischaemia/reperfusion(I/R) injury plays a vital role. Molecular hydrogen (H₂) was reported to have protective effects on I/R injuries of various internal organs. In this study, we investigated the effects of H₂ inhalation on pressure ulcer and the underlying mechanisms. H₂ inhalation significantly reduced wound area, 8‐oxo‐dG level (oxidative DNA damage) and cell apoptosis rates in skin lesions. H₂ remarkably decreased ROS accumulation and enhanced antioxidant enzymes activities by up‐regulating expression of Nrf2 and its downstream components in wound tissue and/or H₂O₂‐treated endothelia. Meanwhile, H₂ inhibited the overexpression of MCP‐1, E‐selectin, P‐selectin and ICAM‐1 in oxidant‐induced endothelia and reduced inflammatory cells infiltration and proinflammatory cytokines (TNF‐α, IL‐1, IL‐6 and IL‐8) production in the wound. Furthermore, H₂ promoted the expression of pro‐healing factors (IL‐22, TGF‐β, VEGF and IGF1) and inhibited the production of MMP9 in wound tissue in parallel with acceleration of cutaneous collagen synthesis. Taken together, these data indicated that H₂ inhalation suppressed the formation of pressure ulcer in a mouse model. Molecular hydrogen has potentials as a novel and alternative therapy for severe pressure ulcer. The therapeutic effects of molecular hydrogen might be related to its antioxidant, anti‐inflammatory, pro‐healing actions.

Inhibiting Bruton's tyrosine kinase rescues mice from lethal influenza-induced acute lung injury

Infection with seasonal influenza A virus (IAV) leads to lung inflammation and respiratory failure, a main cause of death in influenza-infected patients. Previous experiments in our laboratory indicate that Bruton's tyrosine kinase (Btk) plays a substantial role in regulating inflammation in the respiratory region during acute lung injury in mice; therefore, we sought to determine if blocking Btk activity has a protective effect in the lung during influenza-induced inflammation. The Btk inhibitor ibrutinib (also known as PCI-32765) was administered intranasally to mice starting 72 h after lethal infection with IAV. Our data indicate that treatment with the Btk inhibitor not only reduced weight loss and led to survival, but also had a dramatic effect on morphological changes to the lungs, in IAV-infected mice. Attenuation of lung inflammation indicative of acute lung injury, such as alveolar hemorrhage, interstitial thickening, and the presence of alveolar exudate, together with reduced levels of the inflammatory mediators TNFα, IL-1β, IL-6, KC, and MCP-1, strongly suggests amelioration of the pathological immune response in the lungs to promote resolution of the infection. Finally, we observed that blocking Btk specifically in the alveolar compartment led to significant attenuation of neutrophil extracellular traps released into the lung in vivo and neutrophil extracellular trap formation in vitro. Our innovative findings suggest that Btk may be a new drug target for influenza-induced lung injury, and, in general, that immunomodulatory treatment may be key in treating lung dysfunction driven by excessive inflammation.

Activation of aldehyde dehydrogenase 2 slows down the progression of atherosclerosis via attenuation of ER stress and apoptosis in smooth muscle cells

Aldehyde dehydrogenase 2 (ALDH2) is a key mitochondrial enzyme in the metabolism of aldehydes and may have beneficial cardiovascular effects for conditions such as cardiac hypertrophy, heart failure, myocardial I/R injury, reperfusion, arrhythmia, coronary heart disease and atherosclerosis. In this study we investigated the role of ALDH2 in the progression of atherosclerosis and the underlying mechanisms, with a focus on endoplasmic reticulum (ER) stress. A clinical study was performed in 248 patients with coronary heart disease. The patients were divided into two groups according to their ALDH2 genotype. Baseline clinical characteristics and coronary angiography were recorded, and the coronary artery Gensini score was calculated. Serum levels of 4-hydroxy-2-nonenal (4-HNE) were detected. The clinical study revealed that the mutant ALDH2 genotype was an independent risk factor for coronary heart disease. ALDH2 gene polymorphism is closely associated with atherosclerosis and the severity of coronary artery stenosis. Serum levels of 4-HNE were significantly higher in patients with the mutant ALDH2 genotype than in patients with the wild-type ALDH2 genotype. As an in vitro model of atherosclerosis, rat smooth muscle cells (SMCs) were treated with oxygenized low-density lipoprotein (ox-LDL), which significantly elevated the levels of ER markers glucose-regulated protein78 (GRP78), protein kinase R-like ER kinase (PERK), phosphorylated eukaryotic translation initiation factor α subunit (p-eIF2α), activating transcription factor-4 (ATF-4), CEBP homologous protein (CHOP) and 4-HNE in the cells. All the ox-LDL-induced responses were significantly attenuated in the presence of Alda-1 (an ALDH2 activating agent), and accentuated in the presence of daidzin (an ALDH2 inhibitor). Furthermore, pretreatment with ALDH2 activator Alda-1 significantly decreased ox-LDL-induced apoptosis. Similarly, overexpression of ALDH2 protected SMCs against ox-LDL-induced ER stress as well as ER stress-induced apoptosis. These findings suggest that ALDH2 may slow the progression of atherosclerosis via the attenuation of ER stress and apoptosis in smooth muscle cells.

HO‑1 alleviates cholesterol‑induced oxidative stress through activation of Nrf2/ERK and inhibition of PI3K/AKT pathways in endothelial cells

Heme oxygenase‑1 (HO‑1), as an inducible and cytoprotective enzyme, has a protective effect against cellular oxidative stress. In the present study, cholesterol was used to induce lipid overload and increase reactive oxygen species (ROS), leading to oxidative stress in EA.hy926 cells. In the present study, western blotting and immunofluorescence analysis were used to detect the expression level of important molecules in the metabolism process of cholesterol. It was confirmed that cholesterol stimulation upregulated the expression of HO‑1 in a time‑dependent manner via the activation and translocation of nuclear factor erythroid 2‑related factor 2 (Nrf2), activation of the mitogen‑activated protein kinase (MAPK)/extracellular signal‑regulated kinase (ERK) signaling pathway and increasing intercellular Ca2+ ([Ca2+]i) concentration. The results showed that increasing the expression of HO‑1 decreased activation of the phosphoinositide 3‑kinase (PI3K)/AKT signaling pathway and inhibited the expression of c‑Myc. It was confirmed that cholesterol‑mediated oxidative damage in vascular endothelial cells induced an increase in the expression of HO‑1 via the activation of Nrf2 and the MAPK/ERK signaling pathway, and increasing the [Ca2+]i concentration. The overexpression of HO‑1 alleviated oxidative damage through inhibition of the PI3K/AKT signaling pathway and downregulation of the expression of c‑Myc.

HO-1/EBP interaction alleviates cholesterol-induced hypoxia through the activation of the AKT and Nrf2/mTOR pathways and inhibition of carbohydrate metabolism in cardiomyocytes

Heme oxygenase-1 (HO-1) is an inducible and cytoprotective enzyme that provides a defense against oxidant damage. The present study screened 137 HO-1/interacting proteins using a profound co-immunoprecipitation (Co-IP) coupled with proteomics, and profiled the global HO-1 interactome network, including oxidative phosphorylation, endoplasmic reticulum and transport vesicle functions. Among these molecules, we observed that a novel interactor, emopamil-binding protein (EBP), is closely related to the cholesterol metabolism process. This study demonstrated that cholesterol promotes excessive oxidative stress and alters the energy metabolism in cardiomyocytes, further triggering numerous cardiovascular diseases. We observed that cholesterol caused the overexpression of EBP and HO-1 by the activation of AKT and Nrf2/mTOR pathways. In addition, HO-1 and EBP performed a myocardial protective function. The overexpression of HO-1 alleviated the cholesterol-induced excessive oxidative stress status by inhibition of the carbohydrate metabolism. Notably, we also confirmed that the loss of partial HO-1 activity aggravated the oxidative damage and cardiac systolic function induced by a high-fat diet in HO-1 heterozygous (HO-1^+/−) mice. These findings indicate that the HO-1/EBP interaction plays a protective role in alleviating the dysfunction of oxidative stress and cardiac systolic function induced by cholesterol stimulation.

Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water

Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles.

Hydrogen-Rich Water Ameliorates Total Body Irradiation-Induced Hematopoietic Stem Cell Injury by Reducing Hydroxyl Radical

We examined whether consumption of hydrogen-rich water (HW) could ameliorate hematopoietic stem cell (HSC) injury in mice with total body irradiation (TBI). The results indicated that HW alleviated TBI-induced HSC injury with respect to cell number alteration and to the self-renewal and differentiation of HSCs. HW specifically decreased hydroxyl radical (^∙OH) levels in the c-kit⁺ cells of 4 Gy irradiated mice. Proliferative bone marrow cells (BMCs) increased and apoptotic c-kit⁺ cells decreased in irradiated mice uptaken with HW. In addition, the mean fluorescence intensity (MFI) of γ-H2AX and percentage of 8-oxoguanine positive cells significantly decreased in HW-treated c-kit⁺ cells, indicating that HW can alleviate TBI-induced DNA damage and oxidative DNA damage in c-kit⁺ cells. Finally, the cell cycle (P21), cell apoptosis (BCL-XL and BAK), and oxidative stress (NRF2, HO-1, NQO1, SOD, and GPX1) proteins were significantly altered by HW in irradiated mouse c-kit⁺ cells. Collectively, the present results suggest that HW protects against TBI-induced HSC injury.

High-density lipoprotein inhibits ox-LDL-induced adipokine secretion by upregulating SR-BI expression and suppressing ER Stress pathway

Endoplasmic reticulum stress (ERS) in adipocytes can modulate adipokines secretion. The aim of this study was to explore the protective effect of high-density lipoprotein (HDL) on oxidized low-density lipoprotein (ox-LDL)-induced ERS-C/EBP homologous protein (CHOP) pathway-mediated adipokine secretion. Our results showed that serum adipokines, including visfatin, resistin and TNF-α, correlated inversely with serum HDL cholesterol level in patients with abdominal obesity. In vitro, like ERS inhibitor 4-phenylbutyric acid (PBA), HDL inhibited ox-LDL- or tunicamycin (TM, an ERS inducer)-induced increase in visfatin and resistin secretion. Moreover, HDL inhibited ox-LDL-induced free cholesterol (FC) accumulation in whole cell lysate and in the endoplasmic reticulum. Additionally, like PBA, HDL inhibited ox-LDL- or TM-induced activation of ERS response as assessed by the decreased phosphorylation of protein kinase-like ER kinase and eukaryotic translation initiation factor 2α and reduced nuclear translocation of activating transcription factor 6 as well as the downregulation of Bip and CHOP. Furthermore, HDL increased scavenger receptor class B type I (SR-BI) expression and SR-BI siRNA treatment abolished the inhibitory effects of HDL on ox-LDL-induced FC accumulation and CHOP upregulation. These data indicate that HDL may suppress ox-LDL-induced FC accumulation in adipocytes through upregulation of SR-BI, subsequently preventing ox-LDL-induced ER stress-CHOP pathway-mediated adipocyte inflammation.

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).

Baicalin protects against intestinal ischemia-reperfusion injury by attenuating excessive activation of inositol requiring protein 1α

AIM: To investigate the protective effect of baicalin against intestinal ischemia-reperfusion injury (IIRI) and the role of inositol requiring protein 1α (IRE1α) in this process.

METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into three groups (n = 8): a sham group in which rats underwent laparotomy, an IIRI group in which rats were subjected to occlusion of the superior mesenteric artery for 30 min and reperfusion for 6 h, and a baicalin pretreatment group in which rats were given intraperitoneal injection of baicalin (100 mg/kg) about 30 min before IIRI induction. The levels of tumor necrosis factor α (TNF-α) in intestinal tissues and intestinal fatty acid-binding protein (IFABP) in plasma were detected by ELISA. Cell apoptosis was assessed by TUNEL assay. The expression of IRE1α and phosphorylated IRE1α (p-IRE1α) was detected by immunohistochemical staining. Western blot was applied to detect the expression of GRP78 protein in intestinal tissues.

RESULTS: Compared with the sham group, the expression of p-IRE1α (41.88 ± 3.43 vs 19.55 ± 2.16), IRE1α (51.3 ± 4.16 vs 9.97 ± 1.34), the level of TNF-α (139.70 ng/L ± 19.72 ng/L vs 16.41 ng/L ± 1.75 ng/L), cell apoptosis index (40.77% ± 4.70% vs 3.66% ± 0.83%) and IFABP (2.25 ng/mL ± 0.27 ng/mL vs 0.63 ng/mL ± 0.07 ng/mL) were significantly increased in the IIRI group (P < 0.01 for all). Compared with the IIRI group, the expression level of GRP78 (0.60 ± 0.03 vs 0.42 ± 0.02, P < 0.01) was up-regulated, however, the expression of p-IRE1α (26.71 ± 2.43 vs 41.88 ± 3.43) and IRE1α (36.87 ± 2.07 vs 51.39 ± 4.16), the level of TNF-α (93.38 ng/L ± 16.79 ng/L vs 139.70 ng/L ± 19.72 ng/L), cell apoptosis index (29.50% ± 7.66% vs 40.77% ± 4.70%) and IFABP (1.50 ng/mL ± 0.29 ng/mL vs 2.25 ng/mL ± 0.27 ng/mL) were deceased in the baicalin pretreatment group (P < 0.01 for all).

CONCLUSION: Baicalin reduces intestinal ischemia-reperfusion injury by up-regulating GRP78, alleviating endoplasmic reticulum stress and attenuating IRE1α excessive activation.

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

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