Inhalation of water electrolysis-derived hydrogen ameliorates cerebral ischemia-reperfusion injury in rats - A possible new hydrogen resource for clinical use

Advances in nanomedicines: a promising therapeutic strategy for ischemic cerebral stroke treatment

Ischemic stroke, prevalent among the elderly, necessitates attention to reperfusion injury post treatment. Limited drug access to the brain, owing to the blood-brain barrier, restricts clinical applications. Identifying efficient drug carriers capable of penetrating this barrier is crucial. Blood-brain barrier transporters play a vital role in nutrient transport to the brain. Recently, nanoparticles emerged as drug carriers, enhancing drug permeability via surface-modified ligands. This article introduces the blood-brain barrier structure, elucidates reperfusion injury pathogenesis, compiles ischemic stroke treatment drugs, explores nanomaterials for drug encapsulation and emphasizes their advantages over conventional drugs. Utilizing nanoparticles as drug-delivery systems offers targeting and efficiency benefits absent in traditional drugs. The prospects for nanomedicine in stroke treatment are promising.

Molecular Hydrogen: an Emerging Therapeutic Medical Gas for Brain Disorders

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

Microbial hydrogen "manufactory" for enhanced gas therapy and self-activated immunotherapy via reduced immune escape

BACKGROUND

As an antioxidant, hydrogen (H2) can selectively react with the highly toxic hydroxyl radical (·OH) in tumor cells to break the balance of reactive oxygen species (ROS) and cause oxidative stress. However, due to the high diffusibility and storage difficulty of hydrogen, it is impossible to achieve long-term release at the tumor site, which highly limited their therapeutic effect.

RESULTS

Photosynthetic bacteria (PSB) release a large amount of hydrogen to break the balance of oxidative stress. In addition, as a nontoxic bacterium, PSB could stimulate the immune response and increase the infiltration of CD4+ and CD8+ T cells. More interestingly, we found that hydrogen therapy induced by our live PSB did not lead to the up-regulation of PD-L1 after stimulating the immune response, which could avoid the tumor immune escape.

CONCLUSION

Hydrogen-immunotherapy significantly kills tumor cells. We believe that our live microbial hydrogen production system provides a new strategy for cancer hydrogen treatment combining with enhanced immunotherapy without up-regulating PD-L1.

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.

Hydrogen-oxygen therapy alleviates clinical symptoms in twelve patients hospitalized with COVID-19: A retrospective study of medical records

A global public health crisis caused by the 2019 novel coronavirus disease (COVID-19) leads to considerable morbidity and mortality, which bring great challenge to respiratory medicine. Hydrogen-oxygen therapy contributes to treat severe respiratory diseases and improve lung functions, yet there is no information to support the clinical use of this therapy in the COVID-19 pneumonia.A retrospective study of medical records was carried out in Shishou Hospital of Traditional Chinese Medicine in Hubei, China. COVID-19 patients (aged ≥ 30 years) admitted to the hospital from January 29 to March 20, 2020 were subjected to control group (n = 12) who received routine therapy and case group (n = 12) who received additional hydrogen-oxygen therapy. The clinical characteristics of COVID-19 patients were analyzed. The physiological and biochemical indexes, including immune inflammation indicators, electrolytes, myocardial enzyme profile, and functions of liver and kidney, were examined and investigated before and after hydrogen-oxygen therapy.The results showed significant decreases in the neutrophil percentage and the concentration and abnormal proportion of C-reactive protein in COVID-19 patients received additional hydrogen-oxygen therapy.This novel therapeutic may alleviate clinical symptoms of COVID-19 patients by suppressing inflammation responses.

The Anti-Inflammatory Effect of Hydrogen Gas Inhalation and Its Influence on Laser-Induced Choroidal Neovascularization in a Mouse Model of Neovascular Age-Related Macular Degeneration

Background: Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly. Choroidal neovascularization (CNV) is the major pathologic feature of neovascular AMD. Oxidative damages and the ensuing chronic inflammation are representative of trigger events. Hydrogen gas (H₂) has been demonstrated as an antioxidant and plays a role in the regulation of oxidative stress and inflammation. This experiment aimed to investigate the influence of H₂ inhalation on a mouse model of CNV. Methods: Laser was used to induce CNV formation. C57BL/6J mice were divided into five groups: the control group; the laser-only group; and the 2 h, 5 h, and 2.5 h/2.5 h groups that received laser and H₂ inhalation (21% oxygen, 42% hydrogen, and 37% nitrogen mixture) for 2 h, 5 h, and 2.5 h twice every day, respectively. Results: The severity of CNV leakage on fluorescence angiography showed a significant decrease in the H₂ inhalation groups. The mRNA expression of hypoxia-inducible factor 1 alpha and its immediate downstream target vascular endothelial growth factor (VEGF) showed significant elevation after laser, and this elevation was suppressed in the H₂ inhalation groups in an inhalation period length-related manner. The mRNA expression of cytokines, including tumor necrosis factor alpha and interlukin-6, also represented similar results. Conclusion: H₂ inhalation could alleviate CNV leakage in a laser-induced mouse CNV model, and the potential mechanism might be related to the suppression of the inflammatory process and VEGF-driven CNV formation.

High concentration of hydrogen ameliorates lipopolysaccharide-induced acute lung injury in a sirt1-dependent manner

The aim of this study was to investigate the efficacy and underlying mechanism of high concentration of hydrogen on lipopolysaccharide (LPS)-induced acute lung injury (ALI). We have established a corresponding mouse model and examined the function of hydrogen inhalation on lung pathology and pulmonary edema induced by LPS, as well as contents of IL-1β, TNF-α and IL-8. The pulmonary microvascular permeability and 66.7 % hydrogen on the expression of sirt1 and its downstream signaling molecules were tested. Results showed that 66.7 % hydrogen alleviated lung pathological changes and pulmonary edema caused by LPS, and reduced the degree of ALI by inhibiting pro-inflammatory cytokine release and oxidative stress response, thereby decreasing the expression of molecules related to intercellular adhesion. sirt1 contributed to the repair of LPS-induced ALI by hydrogen through the regulation of NF-κB and catalase expression. In conclusion, 66.7 % hydrogen protected against LPS-induced ALI by suppressing inflammatory response and oxidative stress mediated by NF-κB and catalase in a sirt1-dependent manner.

High concentration of hydrogen gas alleviates Lipopolysaccharide-induced lung injury via activating Nrf2 signaling pathway in mice

BACKGROUND AND AIMS

The lung is the first organ to fail in sepsis. Our previous studies have proven that 2% molecular hydrogen (H₂) inhalation remain a protective effect on a septic animal model via its anti-inflammatory and anti-apoptosis properties. This current research aims to observe the therapeutic effect of high concentration hydrogen (67%, HCH) on lipopolysaccharide (LPS) induced acute lung injury (ALI), and further investgate the role of Nrf2 signaling pathway.

METHODS

ALI model was induced by LPS areosol inhalation. HCH were treated for 1 h at 1 and 6 h after modelling. Lung tissues and bronchoalveolar lavage fluid (BALF) were collected 4 and 24 h after the exposure of LPS. The histological scores, wet/dry weight ratios, myeloperoxidase (MPO) activity, protein content and cytokine levels in BALF, apoptosis condition of lung cells, expression of Nrf2 and NF-κB were assessed in both wild type and Nrf2-knockout mice.

RESULTS

HCH Inhalation significantly alleviated LPS-induced pathological alterations of lung, and reduced the protein concentration, the wet/dry weight ratio, and the MPO activity of lung tissue. HCH Inhalation improved LPS-induced increasement in caspase-3 activity and the number of TUNEL-positive cells. HCH inhalation attenuated the LPS induced increased total cell content and polymorphonuclear granulocyte content, and pro-inflammatory cytokines, Nrf2 and NF-κB expression. HCH could not produce protective effct in Nrf2-knockout mice.

CONCLUSION

HCH can effectively alleviate LPS-induced ALI, which may be related to activation of Nrf2 signaling pathway and inhibition of inflammatory response and cell apoptosis mediated by NF-κB.

Nose-to-brain delivery of borneol modified tanshinone IIA nanoparticles in prevention of cerebral ischemia/reperfusion injury

Targeted treatment of cerebral ischemia/reperfusion injury (CIRI) remains a problem due to the difficulty in drug delivery across the blood–brain barrier (BBB). In this study, we developed Bo-TSA-NP, a novel tanshinone IIA (TSA) loaded nanoparticles modified by borneol, which has long been proved with the ability to enhance other drugs’ transport across the BBB. The Bo-TSA-NP, with a particle size of about 160 nm, drug loading of 3.6%, showed sustained release and P-glycoprotein (P-gp) inhibition property. It demonstrated a significantly higher uptake by 16HBE cells in vitro through the clathrin/caveolae-mediated endocytosis and micropinocytosis. Following intranasal (IN) administration, Bo-TSA-NP significantly improved the preventive effect on a rat model of CIRI with improved neurological scores, decreased cerebral infarction areas and a reduced content of malondialdehyde (MDA) and increased activity of superoxide dismutase (SOD) in rat brain. In conclusion, these results indicate that Bo-TSA-NP is a promising nose-to-brain delivery system that can enhance the prevention effect of TSA on CIRI.

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.

Molecular Hydrogen Application in Stroke: Bench to Bedside

Stroke is a major cause of mortality and morbidity worldwide. Effective treatments are limited. Molecular hydrogen is emerging as a novel medical gas with therapeutic potential for various neurological diseases, including stroke. We reviewed the experimental and clinical findings of the effects of molecular hydrogen therapy in stroke patients and models. The underlying neuroprotective mechanisms against stroke pathology were also discussed.

Hydrogen gas represses the progression of lung cancer via down-regulating CD47

Hydrogen gas (H₂) has been identified to play an anti-tumor role in several kinds of cancers, but the molecular mechanisms remain largely unknown. In our previous study, our project group found that H₂ could decrease the expression of CD47 in lung cancer A549 cells via the next-generation sequencing, indicating that CD47 might be involved in H₂-mediated lung cancer repression. Therefore, the present study aimed to explore the effects of CD47 on H₂-induced lung cancer repression. Western blotting and real-time PCR (RT-PCR) assays were used to detect the levels of proteins and mRNAs, respectively. Cell proliferation, invasion, migration and apoptosis were detected by using the cell counting kit-8 (CCK-8), Transwell chambers, wound healing and flow cytometry assays, respectively. The results showed that H₂ treatment caused decreases in the expression levels of CD47 and cell division control protein 42 (CDC42) in a dose-dependent manner. Up-regulation of CD47 abolished H₂ roles in promoting lung cancer cell apoptosis and repressing cell growth, invasion and migration in both A549 and H1975 cell lines. However, knockdown of CD47 enhanced H₂ role in lung cancer inhibition. Moreover, we also observed that H₂ treatment induced obvious inhibitions in the expression levels of CDC42 and CD47 in mice tumor tissues, as well as reinforced macrophage-mediated phagocytosis in A549 and H1975 cells. In conclusion, the current study reveals that H₂ inhibits the progression of lung cancer via down-regulating CD47, which might be a potent method for lung cancer treatment.

Hydrogen inhibits the proliferation and migration of gastric cancer cells by modulating lncRNA MALAT1/miR-124-3p/EZH2 axis

Background

Gastric cancer is one of the most prevalent and deadly malignancies without efficient treatment option. This study aimed to investigate the effect of hydrogen gas on the behavior of gastric cancer cells.

Methods

Gastric cancer cell lines MGC-803 and BGC-823 were treated with or without H₂ /O₂ gas mixture (66.7%:33.3% v/v). Proliferation and migration were assessed by MTT and scratch wound healing assays respectively. The expression of lncRNA MALAT1, miR-124-3p, and EZH2 was analyzed by real-time quantitative PCR and/or western blot. Tumor growth was estimated using xenograft mouse model.

Results

H₂ gas significantly inhibited gastric tumor growth in vivo and the proliferation, migration, and lncRNA MALAT1 and EZH2 expression of gastric cancer cells while upregulated miR-124-3p expression. LncRNA MALAT1 overexpression abolished all the aforementioned effects of H₂. LncRNA MALAT1 and miR-124-3p reciprocally inhibited the expression of each other. MiR-124-3p mimics abrogated lncRNA MALAT1 promoted EZH2 expression and gastric cancer cell proliferation and migration.

Conclusions

These data demonstrated that H₂ might be developed as a therapeutics of gastric cancer and lncRNA MALAT1/miR-124-3p/EZH2 axis could be a target for intervention.

The condition of the hairline of Chinchilla lanigera after the introduction of a hydrogen antioxidant into the diet

It was found that the inclusion of water enriched with molecular hydrogen into the diet of a long-tailed chinchilla changed the fur quality indicators. In animals of the experimental group, the guard and downy hairs were thinner than in the control group. The length of downy hair in the experimental group was higher, the number of hairs in the follicle in the chinchillas of the experimental group was greater than in the control group, besides, the hair was stronger and softer. The animals of the experimental group showed less tendency to gnaw out fur. When considering the data on the chemical composition, it was found that in the dry matter of the hair of the animals of the experimental group, there were less organic substances, and there were more minerals in comparison with the animals of the control group.

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

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

Influence of molecular hydrogen on behavioral adaptation of Сhinchilla lanigera taking into account gender factor in conditions of cage keeping

It was found that the inclusion of water enriched with molecular hydrogen in the diet of animals increased the overall proportion of active behavior. According to the form of behavior "moving around the cage", it was found that males and females of the experimental group spent more time than animals of the control group. Males of the experimental group were 24% more active at night, and females were 60% more active than in the control group. In the daily dynamics, the period of activity of animals in the experimental group was from 19:00 to 8:00, and in the control group-from 22:00 to 8:00. In the daily balance according to the form of behavior "moving around the cage", chinchillas of the experimental group spent 5% more than in the control group.

Role of hydrogen in traumatic brain injury: a narrative review

Traumatic brain injury (TBI) is a serious global public health problem. Survivors of TBI often suffer from long-term disability, which puts a heavy burden on society and families. Unfortunately, up to now, there is no efficacious treatment for TBI patients in clinical practice. As a reducing gas, hydrogen has been shown to be neuroprotective in multiple cerebral disease models; however, its efficacy in TBI remains controversial. In this review, we will focus on the results of hydrogen in experimental TBI, elaborate the potential mechanisms, and put forward for future researches based on our current understanding and views.

Saturated hydrogen alleviates CCl4-induced acute kidney injury via JAK2/STAT3/p65 signaling

Objectives

This study assessed the protective effects of saturated hydrogen against CCl₄-induced acute kidney injury (AKI) in mice, and investigated signaling pathways activated by exposure to saturated hydrogen.

Methods

A mouse model of CCl₄-induced AKI was established; some mice were treated with saturated hydrogen. Levels of cystatin C and kidney injury molecule 1 were determined using enzyme-linked immunosorbent assays. Blood urea nitrogen and serum creatinine were measured on a fully automated biochemical analyzer. Interleukin-8, tumor necrosis factor-α, and interferon-γ in serum and kidney tissues were measured using enzyme-linked immunosorbent assays. Malondialdehyde, glutathione peroxidase, and superoxide dismutase in kidney tissues were measured using biochemical kits. Oxidative stress in kidney tissues was analyzed using nitrotyrosine staining. Expression levels of p-JAK2, p-STAT3, and p-p65 signal protein were assayed by immunohistochemistry and western blotting.

Results

Compared with untreated mice with CCl₄-induced AKI, mice that were treated with saturated hydrogen exhibited improved renal function and reduced oxidative stress. Moreover, expression levels of p-JAK2, p-STAT3, and p-p65 were significantly reduced in mice treated with saturated hydrogen, compared with expression levels in untreated mice.

Conclusions

Treatment with saturated hydrogen can reduce oxidative stress and inflammatory cytokine activation, potentially through inhibition of JAK2/STAT3/p65 signaling, thereby protecting against AKI.

Ischemia Reperfusion Injury: Opportunities for Nanoparticles

Ischemia reperfusion (IR)-induced oxidative stress, accompanied by inflammatory responses, contributes to morbidity and mortality in numerous diseases such as acute coronary syndrome, stroke, organ transplantation, and limb injury. Ischemia results in profound hypoxia and tissue dysfunction, whereas subsequent reperfusion further aggravates ischemic tissue damage through inducing cell death and activating inflammatory responses. In this review, we highlight recent studies of therapeutic strategies against IR injury. Furthermore, nanotechnology offers significant improvements in this area. Hence, we also review recent advances in nanomedicines for IR therapy, suggesting them as potent and promising strategies to improve drug delivery to IR-injured tissues and achieve protective effects.

The role of medical gas in stroke: an updated review

Medical gas is a large class of bioactive gases used in clinical medicine and basic scientific research. At present, the role of medical gas in neuroprotection has received growing attention. Stroke is a leading cause of death and disability in adults worldwide, but current treatment is still very limited. The common pathological changes of these two types of stroke may include excitotoxicity, free radical release, inflammation, cell death, mitochondrial disorder, and blood-brain barrier disruption. In this review, we will discuss the pathological mechanisms of stroke and the role of two medical gases (hydrogen and hydrogen sulfide) in stroke, which may potentially provide a new insight into the treatment of stroke.

Hydrogen inhibits microglial activation and regulates microglial phenotype in a mouse middle cerebral artery occlusion model

Microglia participate in bi-directional control of brain repair after stroke. Previous studies have demonstrated that hydrogen protects brain after ischemia/reperfusion (I/R) by inhibiting inflammation, but the specific mechanism of anti-inflammatory effect of hydrogen is poorly understood. The goal of our study is to investigate whether inhalation of high concentration hydrogen (HCH) is able to attenuate I/R-induced microglia activation. Eighty C57B/L male mice were divided into four groups: sham, I/R, I/R + HCH and I/R + N₂/O₂ groups. Assessment of animals happened in “blind” matter. I/R was induced by occlusion of middle cerebral artery for one hour). After one hour, filament was withdrawn, which induced reperfusion. Hydrogen treated I/R animals inhaled mix of 66.7% H₂ balanced with O₂ for 90 minutes, starting immediately after initiation of reperfusion. Control animals (N₂/O₂) inhaled mix in which hydrogen was replaced with N₂ for the same time (90 minutes). The brain injury, such as brain infarction and development of brain edema, as well as neurobehavioral deficits were determined 23 hours after reperfusion. Effect of HCH on microglia activation in the ischemic penumbra was investigated by immunostaining also 23 hours after reperfusion. mRNA expression of inflammation related genes was detected by PCR. Our results showed that HCH attenuated brain injury and consequently reduced neurological dysfunction after I/R. Furthermore, we demonstrated that HCH directed microglia polarization towards anti-inflammatory M2 polarization. This study indicates hydrogen may exert neuroprotective effects by inhibiting the microglial activation and regulating microglial polarization. This study was conducted in agreement with the Animal Care and Use Committee (IACUC) and Institutional Animal Care guidelines regulation (Shanghai Jiao Tong University, China (approval No. A2015-011) in November 2015.

Inhalation of high-concentration hydrogen gas attenuates cognitive deficits in a rat model of asphyxia induced-cardiac arrest

Cognitive deficits are a devastating neurological outcome seen in survivors of cardiac arrest. We previously reported water electrolysis derived 67% hydrogen gas inhalation has some beneficial effects on short-term outcomes in a rat model of global brain hypoxia-ischemia induced by asphyxia cardiac arrest. In the present study, we further investigated its protective effects in long-term spatial learning memory function using the same animal model. Water electrolysis derived 67% hydrogen gas was either administered 1 hour prior to cardiac arrest for 1 hour and at 1-hour post-resuscitation for 1 hour (pre- & post-treatment) or at 1-hour post-resuscitation for 2 hours (post-treatment). T-maze and Morris water maze were used for hippocampal memory function evaluation at 7 and 14 days post-resuscitation, respectively. Neuronal degeneration within hippocampal Cornu Ammonis 1 (CA1) regions was examined by Fluoro-Jade staining ex vivo. Hippocampal deficits were detected at 7 and 18 days post-resuscitation, with increased neuronal degeneration within hippocampal CA1 regions. Both hydrogen gas treatment regimens significantly improved spatial learning function and attenuated neuronal degeneration within hippocampal CA1 regions at 18 days post-resuscitation. Our findings suggest that water electrolysis derived 67% hydrogen gas may be an effective therapeutic approach for improving cognitive outcomes associated with global brain hypoxia-ischemia following cardiac arrest. The study was approved by the Animal Health and Safety Committees of Loma Linda University, USA (approval number: IACUC #8170006) on March 2, 2017.

Recent advances in the neuroprotective effects of medical gases

Central nervous system injuries are a leading cause of death and disability worldwide. Although the exact pathophysiological mechanisms of various brain injuries vary, central nervous system injuries often result in an inflammatory response, and subsequently lead to brain damage. This suggests that neuroprotection may be necessany in the treatment of multiple disease models. The use of medical gases as neuroprotective agents has gained great attention in the medical field. Medical gases include common gases, such as oxygen, hydrogen and carbon dioxide; hydrogen sulphide and nitric oxide that have been considered toxic; volatile anesthetic gases, such as isoflurane and sevoflurane; and inert gases like helium, argon, and xenon. The neuroprotection from these medical gases has been investigated in experimental animal models of various types of brain injuries, such as traumatic brain injury, stroke, subarachnoid hemorrhage, cerebral ischemic/reperfusion injury, and neurodegenerative diseases. Nevertheless, the transition into the clinical practice is still lagging. This delay could be attributed to the contradictory paradigms and the conflicting results that have been obtained from experimental models, as well as the presence of inconsistent reports regarding their safety. In this review, we summarize the potential mechanisms underlying the neuroprotective effects of medical gases and discuss possible candidates that could improve the outcomes of brain injury.

Oral Administration of Si-Based Agent Attenuates Oxidative Stress and Ischemia-Reperfusion Injury in a Rat Model: A Novel Hydrogen Administration Method

Organ ischemia-reperfusion injury (IRI), which is unavoidable in kidney transplantation, induces the formation of reactive oxygen species and causes organ damage. Although the efficacy of molecular hydrogen (H2) in IRI has been reported, oral intake of H2-rich water and inhalation of H2 gas are still not widely used in clinical settings because of the lack of efficiency and difficulty in handling. We successfully generated large quantities of H2 molecules by crushing silicon (Si) to nano-sized Si particles (nano-Si) which were allowed to react with water. The nano-Si or relatively large-sized Si particles (large-Si) were orally administered to rats with renal IRI. Animals were divided into four groups: sham, IRI, IRI + nano-Si, and IRI + large-Si. The levels of serum creatinine and urine protein were significantly decreased 72 h following IRI in rats that were administered nano-Si. The levels of oxidative stress marker, urinary 8-hydroxydeoxyguanosine were also significantly decreased with the nano-Si treatment. Transcriptome and gene ontology enrichment analyses showed that the oral nano-Si intake downregulated the biological processes related to oxidative stress, such as immune response, cytokine production, and extrinsic apoptotic signaling pathway. Alterations in the regulation of a subset of genes in the altered pathways were validated by quantitative polymerase chain reaction. Furthermore, immunohistochemical analysis demonstrated that the nano-Si treatment alleviated interstitial macrophage infiltration and tubular apoptosis, implicating the anti-inflammatory and anti-apoptotic effects of nano-Si. In conclusion, renal IRI was attenuated by the oral administration of nano-Si, which should be considered as a novel H2 administration method.

Hydrogen Inhalation Attenuates Oxidative Stress Related Endothelial Cells Injury After Subarachnoid Hemorrhage in Rats

Background: Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease with poor clinical outcome. Nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome serves a key role in inflammatory response, which may lead to endothelial cell injury and blood-brain barrier (BBB) disruption. Hydrogen (H₂) is considered a neuroprotective antioxidant. This study was set out to explore whether hydrogen inhalation protects against SAH induced endothelial cell injury, BBB disruption, microthrombosis and vasospasm in rats.

Methods: One hundred eighty-two male SD rats were used for the study. SAH was induced by endovascular perforation. H2 at a concentration of 3.3% was inhaled beginning at 0.5 h after SAH for duration of 30, 60 or 120 min, followed by single administration or once daily administration for 3 days. The temporal expression of NLRP3 and ASC in the brain was determined, with the effect of hydrogen inhalation evaluated. In addition, brain water content, oxidative stress markers, inflammasome, apoptotic markers, microthrombosis, and vasospasm were evaluated at 24 or 72 h after SAH.

Results: The expression of NLRP3 and ASC were upregulated after SAH associated with elevated expression of MDA, 8-OHdG, 4-HNE, HO-1, TLR4/NF-κB, inflammatory and apoptotic makers. Hydrogen inhalation reduced the expression of these inflammatory and apoptotic makers in the vessels, brain edema, microthrombi formation, and vasospasm in rats with SAH relative to control. Hydrogen inhalation also improved short-term and long-term neurological recovery after SAH.

Conclusion: Hydrogen inhalation can ameliorate oxidative stress related endothelial cells injury in the brain and improve neurobehavioral outcomes in rats following SAH. Mechanistically, the above beneficial effects might be related to, at least in part, the inhibition of activation of ROS/NLRP3 axis.

Effects of a high concentration of hydrogen on neurological function after traumatic brain injury in diabetic rats

Reactive oxygen species, inflammation, and apoptosis are major contributors to secondary injuries that follow traumatic brain injury (TBI) in diabetic patients. Hydrogen (H₂) can selectively neutralize reactive oxygen species and downregulate inflammatory and apoptotic factors. Therefore, we investigated the effects of inhaled high and low concentrations of hydrogen on neurological function after TBI in diabetic rats and the potential mechanism. We found that the inhalation of high concentrations of H₂ significantly improved outcomes following TBI in diabetic rats. The inhalation of 42% H₂ for one hour per day for 48 h significantly reduced brain edema, decreased the extravasation of sodium fluorescein, and reduced oxidative stress markers (p < 0.05). In addition, the inhalation of a high concentration of H₂ (42% for one hour per day for 7 days) improved neurological deficits (p < 0.05) and reduced the expression of apoptotic protein markers (p < 0.05). However, the inhalation of 3% H₂ did not yield significant effects. These results showed that the inhalation of 42% H₂ can alleviate nerve damage and improve neurological function after TBI in diabetic rats. Therefore, the inhalation of a high concentration of H₂ may be associated with the treatment of traumatic brain injuries.

Hydrogen gas protects against delayed encephalopathy after acute carbon monoxide poisoning in a rat model

Objective: The protective effects of 2%-4% hydrogen gas in delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) have been previously reported. This study aimed to assess the neuroprotective effects of high concentration hydrogen (HCH) on DEACMP.Methods: A total of 36 male Sprague-Dawley rats were divided into 3 groups. In the DEACMP group, rats were exposed to CO to induce CO poisoning; in the HCH group, the animals were exposed to 67% H₂ and 33% O₂ at 3,000 mL/min for 90 min immediately after CO poisoning. Neurological function was evaluated at 1 and 9 days after poisoning. Then, the contents of malondialdehyde, 3-nitrotyrosine and 8-hydroxy-2-deoxyguanosine, as well as superoxide dismutase activity in the serum, cortex and hippocampus were detected by ELISA. Additionally, the mRNA and protein expression levels of Nrf2 and downstream genes were detected by RT-PCR and Western blotting, respectively.Results: Our results showed that CO poisoning significantly impaired neurological function which was improved over time, and HCH markedly attenuated neurological impairment following CO poisoning. In addition, CO poisoning resulted in increased levels of malondialdehyde, 3-nitrotyrosine and 8-hydroxy-2-deoxyguanosine and markedly reduced superoxide dismutase activity at 1 and 9 days, which were significantly inhibited by HCH at 9 days. Finally, CO poisoning increased the mRNA and protein levels of Nrf2 and downstream genes, and HCH further induced the anti-oxidative capability.Conclusion: These findings indicate the neuroprotective effects of HCH on DEACMP, which are related to the activation of Nrf2 signaling pathway.

Acid-Responsive H2 -Releasing 2D MgB2 Nanosheet for Therapeutic Synergy and Side Effect Attenuation of Gastric Cancer Chemotherapy

The hydrogen molecule is recognized as a high potential to attenuate toxic side effects of chemotherapy and also enhance chemotherapeutic efficacy, and the development of a novel hydrogen-generating prodrug for facile, safe, and efficient hydrogen delivery is vitally important for combined hydrogenochemotherapy but is still challenging. Here, targeting gastric cancer, a 2D magnesium boride nanosheet (MBN) is synthesized as a new type of acid-responsive hydrogen-releasing prodrug by an ultrasound-assisted chemical etching route, which is used to realize hydrogenochemotherapy by combination of facile oral administration of polyvinylpyrrolidone (PVP)-encapsulating MBN (MBN@PVP) pills with routine intravenous injection of doxorubicin (DOX). The MBN@PVP pill has high stability in normal tissues/blood environments as well as high gastric acid-responsiveness with sustained release behavior, which matches well with its metabolism rate in the stomach in great favor of continuous and long-term hydrogen administration. Hydrogenochemotherapy with DOX+MBN@PVP has remarkably prolonged the survival time of gastric tumor-bearing mice by reducing the toxic side effects of chemotherapy. The mechanism for therapeutic synergy and side effect attenuation of hydrogenochemotherapy is discovered to be derived from the selectivity of hydrogen molecules in inhibiting aerobic respiration of gastric cells but activating aerobic respiration of normal cells including marrow mesenchymal stem cells and cardiac, hepatic, and splenic cells.

UPLC-QTOF/MS-Based Metabolomics Reveals the Protective Mechanism of Hydrogen on Mice with Ischemic Stroke

As a reductive gas, hydrogen plays an antioxidant role by selectively scavenging oxygen free radicals. It has been reported that hydrogen has protective effects against nerve damage caused by ischemia-reperfusion in stroke, but the specific mechanism is still unclear. Therefore, this study aims to investigate the protective effects of hydrogen on stroke-induced ischemia-reperfusion injury and its detailed mechanism. Two weeks after the inhalation of high concentrations (66.7%) of hydrogen, middle cerebral artery occlusion (MCAO) was induced in mice using the thread occlusion technique to establish an animal model of the focal cerebral ischemia-reperfusion. Then, a metabolomics analysis of mouse cerebral cortex tissues was first performed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) to study the metabolic changes and protective mechanisms of hydrogen on stroke ischemia-reperfusion injury. According to the metabolomic profiling of cortex tissues, 29 different endogenous metabolites were screened, including palmitoyl-L-carnitine, citric acid, glutathione, taurine, acetyl-L-carnitine, N-acetylaspartylglutamic acid (NAAG), L-aspartic acid, lysophosphatidylcholine (LysoPC) and lysophosphatidylethanolamine (LysoPE). Through pathway analysis, the metabolic pathways were concentrate on the glutathione pathway and the taurine pathway, mitochondrial energy metabolism and phospholipid metabolism that related to the oxidative stress process. This result reveals that hydrogen may protect against ischemic stroke by reducing oxidative stress during ischemia-reperfusion, thereby protecting nerve cells from reactive oxygen species(ROS).

Hydrogen and Oxygen Mixture to Improve Cardiac Dysfunction and Myocardial Pathological Changes Induced by Intermittent Hypoxia in Rats

Obstructive sleep apnea (OSA) can cause intermittent changes in blood oxygen saturation, resulting in the generation of many reactive oxygen species (ROS). To discover new antioxidants and clarify the endoplasmic reticulum (ER) stress involved in cardiac injury in OSA, we established a chronic intermittent hypoxia (CIH) rat model with a fraction of inspired O₂ (FiO₂) ranging from 21% to 9%, 20 times/h for 8 h/day, and the rats were treated with H₂-O₂ mixture (67% hydrogen and 33% oxygen) for 2 h/day for 35 days. Our results showed that H₂-O₂ mixture remarkably improved cardiac dysfunction and myocardial fibrosis. We found that H₂-O₂ mixture inhalation declined ER stress-induced apoptosis via three major response pathways: PERK-eIF2α-ATF4, IRE 1-XBP1, and ATF 6. Furthermore, we revealed that H₂-O₂ mixture blocked c-Jun N-terminal kinase- (JNK-) MAPK activation, increased the ratio of Bcl-2/Bax, and inhibited caspase 3 cleavage to protect against CIH-induced cardiac apoptosis. In addition, H₂-O₂ mixture considerably decreased ROS levels via upregulating superoxide dismutase (SOD) and glutathione (GSH) as well as downregulating NADPH oxidase (NOX 2) expression in the hearts of CIH rats. All the results demonstrated that H₂-O₂ mixture significantly reduced ER stress and apoptosis and that H₂ might be an efficient antioxidant against the oxidative stress injury induced by CIH.

Beneficial effects of hydrogen gas inhalation on a murine model of allergic rhinitis

Allergic rhinitis (AR) is a common chronic inflammatory condition. It has been previously indicated that oxidative stress may contribute to allergic inflammation, including AR. Although molecular hydrogen (H₂), an antioxidative agent, has been effective in treatment of numerous oxidative stress-associated diseases, the effect of inhalation of a high concentration of H₂ on AR remains unknown. In the current study, female BALB/c mice were sensitized with ovalbumin (OVA) followed by intranasal OVA challenge to establish an animal model of AR. Mice were subjected to exposure to H₂ and the inert gas helium at different frequencies and durations. The frequencies of sneezing/scratching and the body weights of mice were recorded. Histological analysis and multiplex cytokine assays were performed to evaluate the effects of H₂ on AR. Challenge with OVA induced significant nasal mucosa inflammation. H₂ inhalation reduced the infiltration of inflammatory cells into mucosa and lowered the levels of interleukin (IL)-5, IL-13 and monocyte chemoattractant protein-1 in serum. H₂ inhalation slightly increased the level of interferon-γ, however the difference was not statistically significant. Treatment with H₂ limited the weight increase in healthy mice and reversed the weight loss in mice with AR. Furthermore, H₂ inhalation induced a therapeutic effect on AR in a dose-dependent manner. The current results demonstrate that H₂ may demonstrate a therapeutic value for allergic diseases.

Hydrogen as a complementary therapy against ischemic stroke: A review of the evidence

Ischemic stroke is one of the most common sources of mortality in the world. Researchers have been trying to find a complementary therapy to treat ischemic stroke in order to improve its prognosis and expand the therapeutic window for reperfusion treatment. For this reason, many experimental and clinical trials studying the effects of hydrogen against ischemic stroke have been published. Hydrogen gas has been found to eliminate hydroxyl free radical and peroxynitrite anions as well as producing therapeutic effect in patients with ischemic stroke. Many studies have been published illustrating its anti-oxidative, anti-inflammatory and anti-apoptotic effects. The purpose of this article is to review the literature concerning treatment of cerebral I/R injury or ischemic stroke with hydrogen therapy. Specifically, we will examine the appropriate laboratory methods, mechanisms of hydrogen therapy, and outcomes of relevant clinical trials. We conclude this review with a discussion on future investigations of hydrogen therapy to treat ischemic stroke.

Local generation of hydrogen for enhanced photothermal therapy

By delivering the concept of clean hydrogen energy and green catalysis to the biomedical field, engineering of hydrogen-generating nanomaterials for treatment of major diseases holds great promise. Leveraging virtue of versatile abilities of Pd hydride nanomaterials in high/stable hydrogen storage, self-catalytic hydrogenation, near-infrared (NIR) light absorption and photothermal conversion, here we utilize the cubic PdH0.2 nanocrystals for tumour-targeted and photoacoustic imaging (PAI)-guided hydrogenothermal therapy of cancer. The synthesized PdH0.2 nanocrystals have exhibited high intratumoural accumulation capability, clear NIR-controlled hydrogen release behaviours, NIR-enhanced self-catalysis bio-reductivity, high NIR-photothermal effect and PAI performance. With these unique properties of PdH0.2 nanocrystals, synergetic hydrogenothermal therapy with limited systematic toxicity has been achieved by tumour-targeted delivery and PAI-guided NIR-controlled release of bio-reductive hydrogen as well as generation of heat. This hydrogenothermal approach has presented a cancer-selective strategy for synergistic cancer treatment.

Inhalation of high concentration hydrogen gas improves short-term outcomes in a rat model of asphyxia induced-cardiac arrest

Cardiogenic global brain hypoxia-ischemia is a devastating medical problem that is associated with unfavorable neurologic outcomes. Low dose hydrogen gas (up to 2.9%) has been shown to be neuroprotective in a variety of brain diseases. In the present study, we investigated the protective effect of water by electrolysis-derived high concentration hydrogen gas (60%) in a rat model of asphyxia induced-cardiac arrest and global brain hypoxia-ischemia. High concentration hydrogen gas was either administered starting 1 hour prior to cardiac arrest for 1 hour and starting 1 hour post-resuscitation for 1 hour (pre- & post-treatment) or starting 1 hour post-resuscitation for 2 hours (post-treatment). In animals subjected to 9 minutes of asphyxia, both therapeutic regimens tended to reduce the incidence of seizures and neurological deficits within 3 days post-resuscitation. In rats subjected to 11 minutes of asphyxia, significantly worse neurological deficits were observed compared to 9 minutes asphyxia, and pre- & post-treatment had a tendency to improve the success rate of resuscitation and to reduce the seizure incidence within 3 days post-resuscitation. Findings of this preclinical study suggest that water electrolysis-derived 60% hydrogen gas may improve short-term outcomes in cardiogenic global brain hypoxia-ischemia.

Hydrogen inhalation improves mouse neurological outcomes after cerebral ischemia/reperfusion independent of anti-necroptosis

This study aimed to investigate the role of necroptosis in the neuroprotection of hydrogen in a mouse model of cerebral ischemia/reperfusion (I/R) injury. C57BL mice were randomly divided into sham group, I/R group, hydrogen/oxygen group (HO), nitrogen/oxygen group (NO). Middle cerebral artery occlusion (MCAO) for 1 hour followed by reperfusion was introduced to animals which were allowed to inhale 66.7% hydrogen/33.3% oxygen for 90 minutes since the beginning of reperfusion. Mice in NO group inhaled 66.7% nitrogen/33.3% oxygen. 24 hours after MCAO, brain infarction, brain water content and neurological function were evaluated. The protein expression of mixed lineage kinase domain like protein (MLKL) was detected at 3, 6, 12, 24 and 72 hours after reperfusion in HO group and the protein and mRNA expression of MLKL at 24 hours after MCAO in four groups. Hydrogen inhalation significantly reduced infarct volume, attenuated brain edema and improved neurobehavioral deficit in MCAO mice. The MLKL expression increased after MCAO and peaked at 6-24 hours after reperfusion. However, hydrogen inhalation had no significant effect on the MLKL expression at transcriptional and translational levels after MCAO. This study indicates high concentration hydrogen improves mouse neurological outcome after cerebral I/R injury independent of anti-necroptosis.

Molecular hydrogen inhalation attenuates postoperative cognitive impairment in rats

Postoperative cognitive decline is a major clinical problem with high morbidity and mortality after surgery. Many studies have found that molecular hydrogen (H2) has significant neuroprotection against acute and chronic neurological injury by regulating inflammation and apoptosis. In this study, we hypothesized that H2 treatment could ameliorate the development of cognitive impairment following surgery. Adult male rats were subjected to stabilized tibial fracture operation under anesthesia. Two percent of H2 was inhaled for 3 h beginning at 1 h after surgery. Separate cohorts of rats were tested for cognitive function with fear conditioning and the Y-maze test, or euthanized to assess blood-brain barrier integrity, and systemic and hippocampal proinflammatory cytokine and caspase-3 activity. Surgery-challenged animals showed significant cognitive impairment evidenced by a decreased percentage of freezing time and an increased number of learning trials on days 1, 3, and 7 after operation, which were significantly improved by H2 treatment. Furthermore, H2 treatment significantly ameliorated the increase in serum and hippocampal proinflammatory cytokines tumor necrosis factor-α, interleukin-1β, interleukin-6, and high-mobility group protein 1 in surgery-challenged animals. Moreover, H2 treatment markedly improved blood-brain barrier integrity and reduced caspase-3 activity in the hippocampus of surgery-challenged animals. These findings suggest that H2 treatment could significantly mitigate surgery-induced cognitive impairment by regulating inflammation and apoptosis.

Inhalation of hydrogen gas attenuates airway inflammation and oxidative stress in allergic asthmatic mice

Background

Asthma is a worldwide common chronic airway disease that cannot be cured and results in the huge burden in public health. Oxidative stress was considered an important mechanism in the pathogenesis of asthma. Hydrogen gas been demonstrated to function as a novel antioxidant and exert therapeutic antioxidant activity in a number of diseases and the function of this nontoxic gas in asthma was unclear. The purpose of the study aims to examine the effect of inhalation hydrogen gas on the pathophysiology of a mouse model of asthma.

Methods

A murine model of ovalbumin (OVA)-induced allergic airway inflammation was used in this study. Briefly, Mice were sensitized to ovalbumin and received inhalation of 67% high concentration of hydrogen gas for 60 min once a day for 7 consecutive days after OVA or PBS challenge respectively. Lung function was assessed in the apparatus with 4 channels of biological signal system. Morphology and goblet cell hyperplasia were stained by H/E and Periodic acid-Schiff staining. Cytologic classification in the bronchial alveolar lavage fluid (BALF) was analyzed by Wright Giemsa staining. Serum, BALF and lung tissue were collected for biochemical assay. One-way analysis of variance (ANOVA) was used to determine statistical significance between groups. Multiple comparisons were made by Bonferroni’s Multiple Comparison Test by using GraphPad Prism 5 software.

Results

Inhalation of hydrogen gas abrogated ovalbumin-induced the increase in lung resistance. Concomitantly, the asthmatic mice showed severe inflammatory infiltration and goblet cell hyperplasia which were reversed by hydrogen gas inhalation. Hydrogen gas inhalation reduced significantly the number of total cells, eosinophils and lymphocytes in BALF. Increased level of IL-4, IL-13, TNF-α and CXCL15 in the BALF and IL-4 in the serum were decreased significantly after inhalation. Hydrogen gas inhalation markedly upregulated the activity of decreased superoxide dismutase and significantly attenuated the increased level of malondialdehyde and myeloperoxidase.

Conclusions

Hydrogen gas inhalation improves lung function and protects established airway inflammation in the allergic asthmatic mice model which may be associated with the inhibition of oxidative stress process. This study provides a potential alternative therapeutic opportunity for the clinical management of asthma.

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.

High-concentration hydrogen protects mouse heart against ischemia/reperfusion injury through activation of thePI3K/Akt1 pathway

The study investigated the role of Akt1 through the cardioprotection of high-concentration hydrogen (HCH). C57BL/6 mice were randomly divided into the following groups: sham, I/R, I/R + HCH, I/R + HCH + LY294002 (PI3K inhibitor), I/R + HCH + wortmannin (PI3K inhibitor), I/R + LY294002, and I/R + wortmannin. After 45 min of ischemia, HCH (67% H₂ and 33% O₂) was administered to mice during a 90-min reperfusion. To investigate the role of Akt1 in the protective effects of HCH, mice were divided into the following groups: I/R + A-674563 (Akt1 selective inhibitor), I/R + HCH + A-674563, I/R + CCT128930 (Akt2 selective inhibitor), and I/R + HCH + CCT128930. After a 4-h reperfusion, serum biochemistry, histological, western blotting, and immunohistochemical analyses were performed to evaluate the role of the PI3K-Akt1 pathway in the protection of HCH. In vitro, 75% hydrogen was administered to cardiomyocytes during 4 h of reoxygenation after 3-h hypoxia. Several analyses were performed to evaluate the role of the Akt1 in the protective effects of hydrogen. HCH resulted in the phosphorylation of Akt1 but not Akt2, and Akt1 inhibition markedly abolished HCH-induced cardioprotection. Our findings reveal that HCH may exert cardioprotective effects through a PI3K-Akt1-dependent mechanism.

Molecular hydrogen increases resilience to stress in mice

The inability to successfully adapt to stress produces pathological changes that can lead to depression. Molecular hydrogen has anti-oxidative and anti-inflammatory activities and neuroprotective effects. However, the potential role of molecular hydrogen in stress-related disorders is still poorly understood. The present study aims to investigate the effects of hydrogen gas on resilience to stress in mice. The results showed that repeated inhalation of hydrogen-oxygen mixed gas [67%:33% (V/V)] significantly decreased both the acute and chronic stress-induced depressive- and anxiety-like behaviors of mice, assessed by tail suspension test (TST), forced swimming test (FST), novelty suppressed feeding (NSF) test, and open field test (OFT). ELISA analyses showed that inhalation of hydrogen-oxygen mixed gas blocked CMS-induced increase in the serum levels of corticosterone, adrenocorticotropic hormone, interleukin-6, and tumor necrosis factor-α in mice exposed to chronic mild stress. Finally, inhalation of hydrogen gas in adolescence significantly increased the resilience to acute stress in early adulthood, which illustrates the long-lasting effects of hydrogen on stress resilience in mice. This was likely mediated by inhibiting the hypothalamic-pituitary-adrenal axis and inflammatory responses to stress. These results warrant further exploration for developing molecular hydrogen as a novel strategy to prevent the occurrence of stress-related disorders.

PEG-b-(PELG-g-PLL) nanoparticles as TNF-α nanocarriers: potential cerebral ischemia/reperfusion injury therapeutic applications

Brain ischemia/reperfusion (I/R) injury (BI/RI) is a leading cause of death and disability worldwide. However, the outcome of pharmacotherapy for BI/RI remains unsatisfactory. Innovative approaches for enhancing drug sensitivity and recovering neuronal activity in BI/RI treatment are urgently needed. The purpose of this study was to evaluate the protective effects of tumor necrosis factor (TNF)-α-loaded poly(ethylene glycol)-b-(poly(ethylenediamine L-glutamate)-g-poly(L-lysine)) (TNF-α/PEG-b-(PELG-g-PLL)) nanoparticles on BI/RI. The particle size of PEG-b-(PELG-g-PLL) and the loading and release rates of TNF-α were determined. The nanoparticle cytotoxicity was evaluated in vitro using rat cortical neurons. Sprague Dawley rats were preconditioned with free TNF-α or TNF-α/PEG-b-(PELG-g-PLL) polyplexes and then subjected to 2 hours ischemia and 22 hours reperfusion. Brain edema was assessed using the brain edema ratio, and the antioxidative activity was assessed by measuring the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) content in the brain tissue. We further estimated the inflammatory activity and apoptosis level by determining the levels of interleukin-4 (IL-4), IL-6, IL-8, IL-10, and nitric oxide (NO), as well as the expression of glial fibrillary acidic protein (GFAP), intercellular adhesion molecule-1 (ICAM-1), and cysteine aspartase-3 (caspase-3), in the brain tissue. We provide evidence that TNF-α preconditioning attenuated the oxidative stress injury, the inflammatory activity, and the apoptosis level in I/R-induced cerebral injury, while the application of block copolymer PEG-b-(PELG-g-PLL) as a potential TNF-α nanocarrier with sustained release significantly enhanced the bioavailability of TNF-α. We propose that the block copolymer PEG-b-(PELG-g-PLL) may function as a potent nanocarrier for augmenting BI/RI pharmacotherapy, with unprecedented clinical benefits. Further studies are needed to better clarify the underlying mechanisms.