Hydrogen gas inhibits high-mobility group box 1 release in septic mice by upregulation of heme oxygenase 1

HYDROGEN PREVENTS LIPOPOLYSACCHARIDE-INDUCED PULMONARY MICROVASCULAR ENDOTHELIAL CELL INJURY BY INHIBITING STORE-OPERATED Ca 2+ ENTRY REGULATED BY STIM1/ORAI1

ABSTRACT

Background: Sepsis is a type of life-threatening organ dysfunction that is caused by a dysregulated host response to infection. The lung is the most vulnerable target organ under septic conditions. Pulmonary microvascular endothelial cells (PMVECs) play a critical role in acute lung injury (ALI) caused by severe sepsis. The impairment of PMVECs during sepsis is a complex regulatory process involving multiple mechanisms, in which the imbalance of calcium (Ca 2+ ) homeostasis of endothelial cells is a key factor in its functional impairment. Our preliminary results indicated that hydrogen gas (H 2 ) treatment significantly alleviates lung injury in sepsis, protects PMVECs from hyperpermeability, and decreases the expression of plasma membrane stromal interaction molecule 1 (STIM1), but the underlying mechanism by which H 2 maintains Ca 2+ homeostasis in endothelial cells in septic models remains unclear. Thus, the purpose of the present study was to investigate the molecular mechanism of STIM1 and Ca 2+ release-activated Ca 2+ channel protein1 (Orai1) regulation by H 2 treatment and explore the effect of H 2 treatment on Ca 2+ homeostasis in lipopolysaccharide (LPS)-induced PMVECs and LPS-challenged mice. Methods: We observed the role of H 2 on LPS-induced ALI of mice in vivo . The lung wet/dry weight ratio, total protein in the bronchoalveolar lavage fluid, and Evans blue dye assay were used to evaluate the pulmonary endothelial barrier damage of LPS-challenged mice. The expression of STIM1 and Orai1 was also detected using epifluorescence microscopy. Moreover, we also investigated the role of H 2 -rich medium in regulating PMVECs under LPS treatment, which induced injury similar to sepsis in vitro . The expression of STIM1 and Orai1 as well as the Ca 2+ concentration in PMVECs was examined. Results:In vivo , we found that H 2 alleviated ALI of mice through decreasing lung wet/dry weight ratio, total protein in the bronchoalveolar lavage fluid and permeability of lung. In addition, H 2 also decreased the expression of STIM1 and Orai1 in pulmonary microvascular endothelium. In vitro , LPS treatment increased the expression levels of STIM1 and Orai1 in PMVECs, while H 2 reversed these changes. Furthermore, H 2 ameliorated Ca 2+ influx under sepsis-mimicking conditions. Treatment with the sarco/endoplasmic reticulum Ca 2+ adenosine triphosphatase inhibitor, thapsigargin, resulted in a significant reduction in cell viability as well as a reduction in the expression of junctional proteins, including vascular endothelial-cadherin and occludin. Treatment with the store-operated Ca 2+ entry inhibitor, YM-58483 (BTP2), increased the cell viability and expression of junctional proteins. Conclusions: The present study suggested that H 2 treatment alleviates LPS-induced PMVEC dysfunction by inhibiting store-operated Ca 2+ entry mediated by STIM1 and Orai1 in vitro and in vivo .

Hydrogen: A Rising Star in Gas Medicine as a Mitochondria-Targeting Nutrient via Activating Keap1-Nrf2 Antioxidant System

The gas molecules O2, NO, H2S, CO, and CH4, have been increasingly used for medical purposes. Other than these gas molecules, H2 is the smallest diatomic molecule in nature and has become a rising star in gas medicine in the past few decades. As a non-toxic and easily accessible gas, H2 has shown preventive and therapeutic effects on various diseases of the respiratory, cardiovascular, central nervous system, and other systems, but the mechanisms are still unclear and even controversial, especially the mechanism of H2 as a selective radical scavenger. Mitochondria are the main organelles regulating energy metabolism in living organisms as well as the main organelle of reactive oxygen species' generation and targeting. We propose that the protective role of H2 may be mainly dependent on its unique ability to penetrate every aspect of cells to regulate mitochondrial homeostasis by activating the Keap1-Nrf2 phase II antioxidant system rather than its direct free radical scavenging activity. In this review, we summarize the protective effects and focus on the mechanism of H2 as a mitochondria-targeting nutrient by activating the Keap1-Nrf2 system in different disease models. In addition, we wish to provide a more rational theoretical support for the medical applications of hydrogen.

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.

The therapeutic role of nutraceuticals targeting the Nrf2/HO-1 signaling pathway in liver cancer

Liver cancer (L.C.) is the most common cause of cancer death in the United States and the fifth most common globally. The overexpression of nuclear factor E2 related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) caused by oxidative stress has been associated with tumor growth, aggressiveness, treatment resistance, and poor prognosis. Nutraceuticals that inhibit Nrf2/HO-1 signaling may become the most effective strategy to treat liver cancer. Phytochemicals found in fruits and vegetables, also known as nutraceuticals, tend to emerge as chemopreventive agents, with the added benefit of low toxicity and high nutritional values. This paper reviews the present scientific knowledge of the Nrf2/HO-1 signaling as a possible target molecule for chemotherapeutic agents, its basic control mechanisms, and Nrf2/HO-1 inducers produced from natural products that might be employed as cancer chemopreventive drugs. The growing interest in the contribution of the Nrf2/ARE/HO-1 signaling in the development of liver cancer and the Use of nutraceuticals to treat liver cancer by targeting Nrf2/ARE/HO-1. PRACTICAL APPLICATIONS: An increase in Nrf2 expression indicates that Nrf2 is the most important player in liver cancer. Cancer patients are more resistant to chemotherapy because of this erroneous Nrf2 signaling. Furthermore, an increasing body of evidence indicates that activation of the Nrf2/HO-1 pathway results in the production of phase II detoxifying and antioxidant enzymes, which serve a defense purpose in cells. As a consequence, treating liver cancer. This master regulator may be a possibility. Nutraceuticals that reduce Nrf2/HO-1 signaling may be the most effective strategy for preventing liver cancer. The methods of action of numerous natural substances are examined in this article.

Therapeutic Gases and Inhaled Anesthetics as Adjunctive Therapies in Critically Ill Patients

The administration of exogenous oxygen to support adequate gas exchange is the cornerstone of respiratory care. In the past few years, other gaseous molecules have been introduced in clinical practice to treat the wide variety of physiological derangement seen in critical care patients.Inhaled nitric oxide (NO) is used for its unique selective pulmonary vasodilator effect. Recent studies showed that NO plays a pivotal role in regulating ischemia-reperfusion injury and it has antibacterial and antiviral activity.Helium, due to its low density, is used in patients with upper airway obstruction and lower airway obstruction to facilitate gas flow and to reduce work of breathing.Carbon monoxide (CO) is a poisonous gas that acts as a signaling molecule involved in many biologic pathways. CO's anti-inflammatory and antiproliferative effects are under investigation in the setting of acute respiratory distress and idiopathic pulmonary fibrosis.Inhaled anesthetics are widely used in the operative room setting and, with the development of anesthetic reflectors, are now a valid option for sedation management in the intensive care unit.Many other gases such as xenon, argon, and hydrogen sulfide are under investigation for their neuroprotective and cardioprotective effects in post-cardiac arrest syndrome.With all these therapeutic options available, the clinician must have a clear understanding of the physiologic basis, therapeutic potential, and possible adverse events of these therapeutic gases. In this review, we will present the therapeutic gases other than oxygen used in clinical practice and we will describe other promising therapeutic gases that are in the early phases of investigation.

Molecular hydrogen is a potential protective agent in the management of acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome, which is a more severe form of ALI, are life-threatening clinical syndromes observed in critically ill patients. Treatment methods to alleviate the pathogenesis of ALI have improved to a great extent at present. Although the efficacy of these therapies is limited, their relevance has increased remarkably with the ongoing pandemic caused by the novel coronavirus disease 2019 (COVID-19), which causes severe respiratory distress syndrome. Several studies have demonstrated the preventive and therapeutic effects of molecular hydrogen in the various diseases. The biological effects of molecular hydrogen mainly involve anti-inflammation, antioxidation, and autophagy and cell death modulation. This review focuses on the potential therapeutic effects of molecular hydrogen on ALI and its underlying mechanisms and aims to provide a theoretical basis for the clinical treatment of ALI and COVID-19.

Molecular hydrogen is a promising therapeutic agent for pulmonary disease

Molecular hydrogen exerts biological effects on nearly all organs. It has anti-oxidative, anti-inflammatory, and anti-aging effects and contributes to the regulation of autophagy and cell death. As the primary organ for gas exchange, the lungs are constantly exposed to various harmful environmental irritants. Short- or long-term exposure to these harmful substances often results in lung injury, causing respiratory and lung diseases. Acute and chronic respiratory diseases have high rates of morbidity and mortality and have become a major public health concern worldwide. For example, coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. An increasing number of studies have revealed that hydrogen may protect the lungs from diverse diseases, including acute lung injury, chronic obstructive pulmonary disease, asthma, lung cancer, pulmonary arterial hypertension, and pulmonary fibrosis. In this review, we highlight the multiple functions of hydrogen and the mechanisms underlying its protective effects in various lung diseases, with a focus on its roles in disease pathogenesis and clinical significance.

Evaluation of the Molecular Mechanisms of Sepsis Using Proteomics

Sepsis is a complex syndrome promoted by pathogenic and host factors; it is characterized by dysregulated host responses and multiple organ dysfunction, which can lead to death. However, its underlying molecular mechanisms remain unknown. Proteomics, as a biotechnology research area in the post-genomic era, paves the way for large-scale protein characterization. With the rapid development of proteomics technology, various approaches can be used to monitor proteome changes and identify differentially expressed proteins in sepsis, which may help to understand the pathophysiological process of sepsis. Although previous reports have summarized proteomics-related data on the diagnosis of sepsis and sepsis-related biomarkers, the present review aims to comprehensively summarize the available literature concerning “sepsis”, “proteomics”, “cecal ligation and puncture”, “lipopolysaccharide”, and “post-translational modifications” in relation to proteomics research to provide novel insights into the molecular mechanisms of sepsis.

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

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

Perspective of Molecular Hydrogen in the Treatment of Sepsis

Sepsis is the main cause of death in critically ill patients with no effective treatment. Sepsis is lifethreatening organ dysfunction due to a dysregulated host response to infection. As a novel medical gas, molecular hydrogen (H₂) has a therapeutic effect on many diseases, such as sepsis. H₂ treatment exerts multiple biological effects, which can effectively improve multiple organ injuries caused by sepsis. However, the underlying molecular mechanisms of hydrogen involved in the treatment of sepsis remain elusive, which are likely related to anti-inflammation, anti-oxidation, anti-apoptosis, regulation of autophagy and multiple signaling pathways. This review can help better understand the progress of hydrogen in the treatment of sepsis, and provide a theoretical basis for the clinical application of hydrogen therapy in sepsis in the future.

Hydrogen Attenuates Endotoxin-Induced Lung Injury by Activating Thioredoxin 1 and Decreasing Tissue Factor Expression

Endotoxin-induced lung injury is one of the major causes of death induced by endotoxemia, however, few effective therapeutic options exist. Hydrogen inhalation has recently been shown to be an effective treatment for inflammatory lung injury, but the underlying mechanism is unknown. In the current study we aim to investigate how hydrogen attenuates endotoxin-induced lung injury and provide reference values for the clinical application of hydrogen. LPS was used to establish an endotoxin-induced lung injury mouse model. The survival rate and pulmonary pathologic changes were evaluated. THP-1 and HUVECC cells were cultured in vitro. The thioredoxin 1 (Trx1) inhibitor was used to evaluate the anti-inflammatory effects of hydrogen. Hydrogen significantly improved the survival rate of mice, reduced pulmonary edema and hemorrhage, infiltration of neutrophils, and IL-6 secretion. Inhalation of hydrogen decreased tissue factor (TF) expression and MMP-9 activity, while Trx1 expression was increased in the lungs and serum of endotoxemia mice. LPS-stimulated THP-1 and HUVEC-C cells in vitro and showed that hydrogen decreases TF expression and MMP-9 activity, which were abolished by the Trx1 inhibitor, PX12. Hydrogen attenuates endotoxin-induced lung injury by decreasing TF expression and MMP-9 activity via activating Trx1. Targeting Trx1 by hydrogen may be a potential treatment for endotoxin-induced lung injury.

Molecular hydrogen alleviates brain injury and cognitive impairment in a chronic sequelae model of murine polymicrobial sepsis

Sepsis-related encephalopathy (SAE), which causes a series of brain injuries and long-term, potentially irreversible cognitive dysfunction, is closely associated with increased morbidity and mortality. Hydrogen (H2) is a new type of medical gas molecule that has been widely used in the treatment of various diseases in recent years. The aim of the present study was to explore the protective effects of H2 inhalation on brain injury and long-term cognitive impairment in an improved chronic septic mouse model. Male C57BL/6J mice were randomized into four groups: Control, Control + H2, SAE and SAE + H2. The SAE and Control models were established by intraperitoneal injection of human stool suspension or saline in mice. H2 (2%) was inhaled for 60 min at 1 h and 6 h after SAE or Control treatment. The survival rates were recorded for 14 days (days 1-14) and the Morris Water Maze was performed for 7 days (days 8-14). To assess the severity of the brain injury, hematoxylin and eosin staining, Nissl staining, Evans blue (EB) extravasation and the wet/dry weight ratio of brain tissue were detected 24 h after SAE or Control treatment. In addition, inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin 6 (IL-6), high-mobility group box 1 (HMGB1), as well as the protein levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), zonula occludens-1 (ZO-1) and Occludin, were measured 6, 12 and 24 h after SAE or Control treatment. The results showed that H2 treatment increased survival rates, mitigated cognitive impairment, reduced hippocampal histological damage, decreased EB and water content, and decreased the levels of TNF-α, IL-6, HMGB1, Nrf2, HO-1, ZO-1 and Occludin, as compared with the SAE group. These data revealed that 2% H2 could suppress brain damage and improve cognitive function in septic mice by inhibiting oxidative stress, inflammatory response and the sepsis-induced blood-brain barrier (BBB) disruption.

Ultra high-sensitive, prompt response and recovering Pt/(Pt+SiO 2) cermet layer/GaN-based hydrogen sensor for life-saving applications

In this work, we report an ultra-high sensitive (S = 1.4 × 108%), prompt response and recovering Pt/Pt+SiO2 cermet layer/GaN-based hydrogen (H2) sensor. A sensor fabricated with a 15 nm cermet layer, comprising Pt and SiO2, deposited between 15 nm Pt and GaN layers, exhibits significantly enhanced sensitivity in the detection of 4 %H2 by ≈ 300×, as compared to the reference Pt/GaN sensor at ambient temperature (300 K). Furthermore, the sensitivity of the our sensor shows very weak dependence on temperature (T) with maximum sensitivity ([Formula: see text]) reducing from 1.4 × 108% to 2.3 × 107% as temperature increases from 300 to 423 K. The shift in the threshold voltage of the test sensor (ΔV t,test = 767 mV) increases by 50 % as compared to the shift in threshold voltage of the control sensor (ΔV t,control = 511 mV) at 1 mA/cm2. In addition, the cermet sensor also demonstrates fast response/recovery time, which reduces from 4.58 (2.36) seconds to 94 (39) milliseconds as the temperature increases from 300 to 423 K. The maximum sensitivity ([Formula: see text]), response (τ a ) and recovery (τ b ) times of the test sensor when exposed to 10 000 ppm of H2 are 3.9 × 107%, 30 secs and 30.1 secs respectively. The shift in the threshold voltage of the test sensor at 1 mA/cm2 when exposed to 100 ppm, 1000 ppm, 5000 ppm, and 10 000 ppm are 40 mV, 70 mV, 460 mV, and 600 mV, respectively. The 2-Dimensional (2D) trapping of H-atoms by the oxygen atoms present in the Pt+SiO2 cermet layer and porous/compact layer models explains the underlying mechanism, which results in a significant improvement of the sensing characteristics of the test sensor. The Thermionic Emission (TE) model effectively models the current density (J) - voltage (V) characteristics of both control and test sensors, with and without hydrogen. The prompt detection of high percentages of hydrogen in life-saving and commercial fuel applications becomes possible with the Pt+SiO2 cermet-based sensor, with its response and recovery times in the order of milliseconds for a temperature range of 363-423 K.

HMGB1 in kidney diseases

High mobility group box 1 (HMGB1) is a highly conserved nucleoprotein involving in numerous biological processes, and well known to trigger immune responses as the damage-associated molecular pattern (DAMP) in the extracellular environment. The role of HMGB1 is distinct due to its multiple functions in different subcellular location. In the nucleus, HMGB1 acts as a chaperone to regulate DNA events including DNA replication, repair and nucleosome stability. While in the cytoplasm, it is engaged in regulating autophagy and apoptosis. A great deal of research has explored its function in the pathogenesis of renal diseases. This review mainly focuses on the role of HMGB1 and summarizes the pathway and treatment targeting HMGB1 in the various renal diseases which may open the windows of opportunities for the development of desirable therapeutic ends in these pathological conditions.

Chronic molecular hydrogen inhalation mitigates short and long-term memory loss in polymicrobial sepsis

The central nervous system (CNS) is one of the first physiological systems to be affected in sepsis. During the exacerbated systemic inflammatory response at the early stage of sepsis, circulatory inflammatory mediators are able to reach the CNS leading to neuroinflammation and, consequently, long-term impairment in learning and memory formation is observed. The acute treatment with molecular hydrogen (H₂) exerts important antioxidative, antiapoptotic, and anti-inflammatory effects in sepsis, but little is known about the mechanism itself and the efficacy of chronic H₂ inhalation in sepsis treatment. Thus, we tested two hypotheses. We first hypothesized that chronic H₂ inhalation is also an effective therapy to treat memory impairment induced by sepsis. The second hypothesis is that H₂ treatment decreases sepsis-induced neuroinflammation in the hippocampus and prefrontal cortex, important areas related to short and long-term memory processing. Our results indicate that (1) chronic exposure of hydrogen gas is a simple, safe and promising therapeutic strategy to prevent memory loss in patients with sepsis and (2) acute H₂ inhalation decreases neuroinflammation in memory-related areas and increases total nuclear factor E2-related factor 2 (Nrf2), a transcription factorthat regulates a vast group of antioxidant and inflammatory agents expression in these areas of septic animals.

Protective Effects of Hydrogen on Myocardial Mitochondrial Functions in Septic Mice

Enhancement of mitochondrial physiological function prevents sepsis-induced dysfunction. The present study aimed to elucidate the mechanism by which hydrogen (H2) affects mitochondrial function in a wild-type (WT) and homozygous nuclear factor erythroid 2-related factor 2 (Nrf2) knockout (KO, Nrf2-/-) murine model of sepsis. In myocardial tissues with severe sepsis, H2 gas treatment reduced mitochondrial dysfunction, whereas zinc protoporphyrin (ZnPPIX) negated these beneficial effects. H2 treatment upregulated the protein expression of mitofusin-2 (Mfn2), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), and protein heme oxygenase-1 (HO-1) in WT mice with severe sepsis but not in their Nrf2-/- counterparts, and this upregulation was inhibited in the presence of ZnPPIX. In conclusion, the mechanism by which H2 limits organ damage in mice with severe sepsis involves HO-1, whereas the mechanism that limits severe sepsis-related mitochondrial dysfunction involves both HO-1 and Nrf2.

Hydrogen treatment prevents lipopolysaccharide-induced pulmonary endothelial cell dysfunction through RhoA inhibition

BACKGROUND

Pulmonary microvascular endothelial cells (PMVECs) are initial targets of sepsis-induced acute lung injury (ALI). During the apoptosis of PMVECs, tight junctions (TJ) and adherens junctions (AJ) are firstly damaged. Previous studies have suggested hydrogen treatment can protect lung microvasculature of mice from sepsis-induced endothelial dysfunction and maintain the coherence of pulmonary endothelium, but the underlying mechanism remains unclear.

METHODS

We investigated the role of hydrogen-rich medium on regulating intercellular junction proteins under lipopolysaccharide (LPS) treatment which mimicked sepsis in vitro. Changes of cytoskeleton regulatory protein ROCK and RhoA as well as PMVEC apoptotic rate were examined.

RESULTS

LPS treatment reduced the expression levels of occludin and VE-cadherin in PMVECs, while hydrogen-rich medium can recover these changes. Furthermore, H₂ can significantly ameliorate the excessive expression of ROCK and RhoA under sepsis-mimicking condition. The application of RhoA activator U-46619 resulted in a more significant elevation in cell apoptotic rate as well as reduction in the expression of junctional proteins. Using H₂ can almost completely inhibit the effects of RhoA activator.

CONCLUSIONS

Our findings suggest that RhoA is a crucial protein in the signaling pathway of LPS-induced endothelial cell dysfunction. Hydrogen treatment can prevent LPS-induced junctional injury and cell death by inhibiting the activity of RhoA.

Itraq-Based Quantitative Proteomic Analysis of Lungs in Murine Polymicrobial Sepsis with Hydrogen Gas Treatment

Sepsis-associated acute lung injury (ALI), which carries a high morbidity and mortality in patients, has no effective therapeutic strategies to date. Our group has already reported that hydrogen gas (H2) exerts a protective effect against sepsis in mice. However, the molecular mechanisms underlying H2 treatment are not fully understood. This study investigated the effects of H2 on lung injuries in septic mice through the isobaric tags for relative and absolute quantitation (iTRAQ)-based quantitative proteomic analysis. Male ICR mice used in this study were subjected to cecal ligation and puncture (CLP) or sham operation. And 2% H2 was inhaled for 1 h beginning at 1 and 6 h after sham or CLP operation. The iTRAQ-based liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis was preformed to investigate lung proteomics. Sepsis-challenged animals had decreased survival rate, as well as had increased bacterial burden in blood, peritoneal lavage, and lung sample, which were significantly ameliorated by H2 treatment. Moreover, a total of 4,472 proteins were quantified, and 192 differentially expressed proteins were related to the protective mechanism of H2 against sepsis. Functional enrichment analysis showed that H2-related differential proteins could be related to muscle contraction, oxygen transport, protein synthesis, collagen barrier membranes, cell adhesion, and coagulation function. These proteins were significantly enriched in four signaling pathways, and two of which are associated with coagulation. In addition, H2 alleviates ALI in septic mice through downregulating the expression of Sema 7A, OTULIN, and MAP3K1 as well as upregulating the expression of Transferrin. Thus, our findings provide an insight into the mechanism of H2 treatment in sepsis by proteomic approach, which may be helpful to the clinic application of H2 in patients with sepsis.

Hydrogen gas reduces HMGB1 release in lung tissues of septic mice in an Nrf2/HO-1-dependent pathway

BACKGROUND

Lung injury is a vital contributor of mortality in septic patients. Our previous studies have found that molecular hydrogen (H₂), which has anti-oxidant, anti-inflammatory, and anti-apoptosis effects, had a therapeutic effect on a septic animal model through increasing expression of nuclear factor-erythroid 2-related factor 2 (Nrf2). The aim of this research was to investigate the effects of 2% H₂ gas inhalation on sepsis-induced lung injury and its underlying mechanisms.

METHODS

Male wild-type (WT) and Nrf2-knockout (Nrf2-KO) ICR mice underwent sham or cecal ligation and puncture (CLP) operation. Two percent of H₂ gas was inhaled for 60 min beginning at both 1 h and 6 h after sham or CLP surgery. To assess the severity of septic lung injury, the 7-day survival rate, wet/dry (W/D) weight ratio of lung tissue, lung histopathologic score, pro-inflammatory cytokines (tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), high-mobility group box 1 (HMGB1)), anti-inflammatory cytokine (interleukin 10 (IL-10)), antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and heme oxygenase 1 (HO-1)), and an oxidative product (malondialdehyde (MDA)) were detected after sham or CLP operation. The histopathologic changes were observed in lung tissues by hematoxylin and eosin (HE) staining, and pro-inflammatory cytokines (TNF-α and IL-6), anti-inflammatory cytokine (IL-10), antioxidant enzymes (SOD and CAT), and MDA were detected in lung tissues by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results indicated that 2% H₂ gas treatment increased the survival rates, decreased the W/D weight ratio and the lung injury score, alleviated the injuries caused by oxidative stress and inflammation, and induced HO-1 level but reduced HMGB1 level in WT but not Krf2-KO mice. These data reveal that H₂ gas could suppress lung injury in septic mice through regulation of HO-1 and HMGB1 expression and that Nrf2 plays a main role in the protective effects of H₂ gas on lung damage caused by sepsis.

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.

Hydrogen Gas Protects Against Intestinal Injury in Wild Type But Not NRF2 Knockout Mice With Severe Sepsis by Regulating HO-1 and HMGB1 Release

The intestine plays an important role in the pathogenesis of sepsis. Hydrogen gas (H2), which has anti-oxidative, anti-inflammatory, and anti-apoptotic effects, can be effectively used to treat septic mice. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a redox-sensitive master switch that regulates the expression of antioxidant and protective enzymes. This study investigated the effects of 2% H2 on intestinal injuries and the underlying mechanisms in a mouse model of severe sepsis. Male Nrf2 knockout mice (Nrf2-KO) and wild-type (WT) mice were randomized into four groups: sham, sham+H2, cecal ligation and puncture (CLP), and CLP+H2. The survival rate was observed and recorded within 7 days, and pro-inflammatory cytokines (TNF-α, IL-6, HMGB1), anti-inflammatory cytokine (IL-10), antioxidant enzymes (superoxide dismutase, and catalase ), and oxidative products (MDA, 8-iso-PGF2α) were detected in the serum and intestine using an enzyme-linked immunosorbent assay. In addition, the protein and mRNA levels of heme oxygenase-1 (HO-1) and high mobility group box 1 (HMGB1) were measured by Western blotting and quantitative PCR, respectively. Immunofluorescence and immunohistochemistry were used to measure HMGB1 and HO-1 release into the intestine, respectively. The results showed that therapy with 2% H2 increased the survival rate, alleviated the injuries caused by oxidative stress and inflammation, reduced HMGB1 levels but increased HO-1 levels in WT septic mice, but not in Nrf2-KO mice. These data demonstrate that 2% H2 inhalation may be a promising therapeutic strategy for intestinal injuries caused by severe sepsis through the regulation of HO-1 and HMGB1 release. In addition, Nrf2 plays a key role in the protective effects of H2 against intestinal damage in this disease.

The effects of lead exposure on the expression of HMGB1 and HO-1 in rats and PC12 cells

Lead (Pb) is an environmental neurotoxic metal. Chronic exposure to Pb causes deficits of learning and memory in children and spatial learning deficits in developing rats. In this study we investigated the effects of Pb exposure on the expression of HMGB1 and HO-1 in rats and PC12 cells. The animals were randomly divided to three groups: control group; low lead exposure group; high lead exposure group; PC12 cells were divided into 3 groups: 0 μM (control group), 1 μM and 100 μM Pb acetate. The results showed that Pb levels in blood and brain of Pb exposed groups were significantly higher than that of the control group (p < 0.05). The expression of HMGB1 and HO-1 were increased in Pb exposed groups than that of the control group (p < 0.05). Moreover, we found that the up-regulation of HO-1 in Pb exposure environment inhibited the expression of HMGB1.

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

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

Ethyl pyruvate ameliorates inflammatory arthritis in mice

OBJECTIVES

Ethyl pyruvate (EP) is the ethyl ester of pyruvate and has antioxidative and anti-inflammatory effects. This study aimed to evaluate the therapeutic effect of EP in inflammatory arthritis and to identify the underlying mechanisms.

METHODS

Mice with collagen-induced arthritis (CIA) were treated with the vehicle control or EP at 20mg/kg, and clinical and histological analyses were performed on the animals. The differentiation of murine CD4+ T cells into T helper 17 (Th17) cells in the presence of EP was investigated in vitro. The effects of EP on osteoclastogenesis were determined by staining for tartrate-resistant acid phosphatase, and measuring the mRNA levels of osteoclastogenesis-related genes. The expression of high-mobility group box 1 (HMGB1) was evaluated after EP therapy using immunohistochemical staining and Western blotting.

RESULTS

EP significantly improved the clinical and histological features of arthritis in CIA mice. EP suppressed the differentiation of CD4+ T cells into Th17 cells, and inhibited the expression of RORγt. The generation of osteoclasts and osteoclastogenic markers from murine and human monocytes was significantly reduced in the presence of EP. The expression of HMGB1 in the synovium was significantly lower in CIA mice treated with EP, compared to control CIA mice. During osteoclastogenesis, HMGB1 release from monocytes was inhibited in the presence of EP.

CONCLUSIONS

EP attenuated synovial inflammation and bone destruction in the experimental arthritis model through suppression of IL-17 and HMGB-1. The data suggests that EP could be a novel therapeutic agent for the treatment of inflammatory arthritis, such as rheumatoid arthritis.

Immersing lungs in hydrogen-rich saline attenuates lung ischaemia-reperfusion injury

Objectives

Anti-oxidant effects of hydrogen have been reported in studies examining ischaemia-reperfusion injury (IRI). In this study, we evaluated the therapeutic efficacy of immersing lungs in hydrogen-rich saline on lung IRI.

Methods

Lewis rats were divided into three groups: (i) sham, (ii) normal saline and (iii) hydrogen-rich saline. In the first experiment, the left thoracic cavity was filled with either normal saline or hydrogen-rich saline for 1 h. Then, we measured the hydrogen concentration in the left lung using a sensor gas chromatograph ( N = 3 per group). In the second experiment, lung IRI was induced by occlusion of the left pulmonary hilum for 1 h, followed by reperfusion for 3 h. During the ischaemic period, the left thoracic cavity was filled with either normal saline or hydrogen-rich saline. After reperfusion, we assessed lung function, histological changes and cytokine production ( N = 5-7 per group).

Results

Immersing lungs in hydrogen-rich saline resulted in an elevated hydrogen concentration in the lung (6.9 ± 2.9 μmol/1 g lung). After IRI, pulmonary function (pulmonary compliance and oxygenation levels) was significantly higher in the hydrogen-rich saline group than in the normal saline group ( P  < 0.05). Similarly, pro-inflammatory cytokine levels (interleukin-1β and interleukin-6) in the left lung were significantly lower in the hydrogen-rich saline group than in the normal saline group ( P  < 0.05).

Conclusions

Immersing lungs in hydrogen-rich saline delivered hydrogen into the lung and consequently attenuated lung IRI. Hydrogen-rich solution appears to be a promising approach to managing lung IRI.

Heme Oxygenase 1 as a Therapeutic Target in Acute Kidney Injury

A common clinical condition, acute kidney injury (AKI) significantly influences morbidity and mortality, particularly in critically ill patients. The pathophysiology of AKI is complex and involves multiple pathways, including inflammation, autophagy, cell-cycle progression, and oxidative stress. Recent evidence suggests that a single insult to the kidney significantly enhances the propensity to develop chronic kidney disease. Therefore, the generation of effective therapies against AKI is timely. In this context, the cytoprotective effects of heme oxygenase 1 (HO-1) in animal models of AKI are well documented. HO-1 modulates oxidative stress, autophagy, and inflammation and regulates the progression of cell cycle via direct and indirect mechanisms. These beneficial effects of HO-1 induction during AKI are mediated in part by the by-products of the HO reaction (iron, carbon monoxide, and bile pigments). This review highlights recent advances in the molecular mechanisms of HO-1-mediated cytoprotection and discusses the translational potential of HO-1 induction in AKI.

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.

The production of high dose hydrogen gas by the AMS-H-01 for treatment of disease

Hydrogen gas is a new and promising treatment option for a variety of diseases including stroke. Here, we introduce the AMS-H-01, a medically approved machine capable of safely producing ~66% hydrogen gas. Furthermore, we propose the significance of this machine in the future of hydrogen gas research.

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.