Hydrogen-rich saline protects against intestinal ischemia/reperfusion injury in rats

The Landscape of Smart Biomaterial-Based Hydrogen Therapy

Hydrogen (H2) therapy is an emerging, novel, and safe therapeutic modality that uses molecular hydrogen for effective treatment. However, the impact of H2 therapy is limited because hydrogen molecules predominantly depend on the systemic administration of H2 gas, which cannot accumulate at the lesion site with high concentration, thus leading to limited targeting and utilization. Biomaterials are developed to specifically deliver H2 and control its release. In this review, the development process, stimuli-responsive release strategies, and potential therapeutic mechanisms of biomaterial-based H2 therapy are summarized. H2 therapy. Specifically, the produced H2 from biomaterials not only can scavenge free radicals, such as reactive oxygen species (ROS) and lipid peroxidation (LPO), but also can inhibit the danger factors of initiating diseases, including pro-inflammatory cytokines, adenosine triphosphate (ATP), and heat shock protein (HSP). In addition, the released H2 can further act as signal molecules to regulate key pathways for disease treatment. The current opportunities and challenges of H2-based therapy are discussed, and the future research directions of biomaterial-based H2 therapy for clinical applications are emphasized.

Si-based agent alleviated small bowel ischemia-reperfusion injury through antioxidant effects

The progression of small bowel ischemia-reperfusion (IR) injury causes cells in the intestinal tract to undergo necrosis, necessitating surgical resection, which may result in loss of intestinal function. Therefore, developing therapeutic agents that can prevent IR injury at early stages and suppress its progression is imperative. As IR injury may be closely related to oxidative stress, antioxidants can be effective therapeutic agents. Our silicon (Si)-based agent, an antioxidant, generated a large amount of hydrogen in the intestinal tract for a prolonged period after oral administration. As it has been effective for ulcerative colitis, renal failure, and IR injury during skin flap transplantation, it could be effective for small intestinal IR injury. Herein, we investigated the efficacy of an Si-based agent in a mouse model of small intestinal IR injury. The Si-based agent suppressed the apoptosis of small intestinal epithelial cells by reducing the oxidative stress induced by IR injury. In addition, the thickness of the mucosal layer in the small intestine of the Si-based agent-administered group was significantly higher than that in the untreated group, revealing that Si-based agent is effective against small intestinal IR injuries. In the future, Si-based agents may improve the success rate of small intestine transplantation.

The Effect of Antioxidant Astaxanthin on Intestinal Ischemia Reperfusion Damage in Rats

BACKGROUND

Mesenteric ischemia is a frequently encountered disease in surgical clinics, difficult to diagnose, and very mortal if not treated. Our study investigated the effects of astaxanthin, which is known to have potent antioxidant properties and is also known to have anti-inflammatory effects on ischemia-reperfusion (I/R) injury.

METHODS

A total of 32 healthy Wistar albino female rats were used in our study. Subjects were randomized and equally divided into 4 groups; control (laparotomy group only), I/R (transient mesenteric ischemia group only), astaxanthin 1 mg/kg and 10 mg/kg doses. The transient ischemia time was 60 minutes and the reperfusion time was 120 minutes. Tissue samples were taken from intracardiac blood and terminal ileum after reperfusion. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) from blood samples, interleukin-1 (IL-1), IL-6, tumor necrosis factor-α (TNFα), Caspase-3, P53 tests from terminal ileum were studied. Tissue samples were also taken for histopathological evaluation.

RESULTS

At the end of the study, both doses of astaxanthin were found to significantly reduce MDA level, CAT, and SOD enzymatic activity, whereas higher doses of astaxanthin significantly reduced MDA level, CAT, and SOD enzyme activities. In addition, cytokines such as TNFα, IL-1 and IL-6 were found to be reduced at both doses of astaxanthin, but only significantly inhibited at higher doses. We observed that inhibition of apoptosis reduced caspase-3 activity and P53 and deoxyribonucleic acid (DNA) fragmentation.

CONCLUSION

Astaxanthin, a potent antioxidant, and anti-inflammatory, significantly reduces ischemia and reperfusion injury, especially when used at a dose of 10 mg/kg. These data need to be confirmed by larger animal series and clinical studies.

Hydrogen-generating Si-based agent protects against skin flap ischemia-reperfusion injury in rats

Hydrogen is effective against ischemia–reperfusion (I/R) injury in skin flaps. However, the difficulty of continuously administering a sufficient amount of hydrogen using conventional methods has been an issue in the clinical application of hydrogen-based therapy. An Si-based agent administered orally was previously shown to continuously generate a large amount of hydrogen in the intestinal environment. In this study, we assessed the effect of the Si-based agent on the inhibition of I/R injury in skin flaps using a rat model. In the I/R groups, the vascular pedicle of the abdominal skin flap was occluded for three hours followed by reperfusion. In the I/R + Si group, the Si-based agent was administered perioperatively. After reperfusion, flap survival rate, blood flow, oxidative stress markers, inflammatory markers/findings, and degree of apoptosis were evaluated. Flap survival rate was significantly higher, and histological inflammation, apoptotic cells, oxidative stress markers, and levels of inflammatory cytokine mRNA and protein expression were significantly lower, in the I/R + Si group compared to the I/R group. The Si-based agent suppressed oxidative stress, apoptosis, and inflammatory reactions resulting from I/R injury, thereby contributing to improvements in skin flap survival.

Protective Effects of Hydrogen-Rich Saline on Experimental Intestinal Volvulus in Rats

BACKGROUND

Intestinal volvulus can cause morbidity and mortality. Surgical reduction, on the other hand, could result in ischemia-reperfusion (I/R) injury. Hydrogen rich saline solution (HRSS neutralizes free radicals in the body. This study aimed to investigate the effects of HRSS in I/R injury in experimental intestinal volvulus in rats.

METHODS

Thirty rats were randomly allocated into 5 groups. All procedures were done under general anesthesia and sterile conditions in each animal. Five ml/kg of saline and HRSS were administered intraperitoneally (ip) in Sham (Group 1) and HRSS (Group 2) groups, respectively. Groups 3, 4, and 5 constituted the study groups in which volvulus was created in a 5-cm- long ileal segment 2 cm proximal to the ileocecal valve. After 2 hours the volvuli were reduced and following 2 hours of reperfusion, these segments were removed. In volvulus-I/R group (Group 3) no additional procedure was done. HRSS was administered shortly before reperfusion (reduction of the volvulus) in Treatment I (Group 4) and 1 h before experimental volvulus in Treatment II (Group 5) groups. Blood and intestinal tissue samples were obtained from all rats at the 4th hour. Both tissue and blood total oxidant (TOS) and antioxidant status (TAS) levels were determined and tissue histomorphologies were studied. Oxidative stress indices (TOS ÷ TAS) (OSI) were calculated.

RESULTS

Tissue TOS and OSI levels and histomorphological injury scores were statistically lower in treatment groups than I/R group, whereas blood TOS and OSI levels were similar between the groups.

CONCLUSIONS

This study provides biochemical and histomorphological evidence that HRSS prevents intestinal damage in I/R injury caused by volvulus.

Gas and gas-generating nanoplatforms in cancer therapy

Gas therapy is the usage of certain gases with special therapeutic effects for the treatment of diseases. Hydrogen (H₂), nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H₂S) acting as gas signalling molecules are representative gases in cancer therapy. They act directly on mitochondria or nuclei to lead to cell apoptosis. They can also alleviate immuno-suppression in the tumour microenvironment and promote phenotype conversion of tumour-associated macrophages. Moreover, the combination of gas therapy and other traditional therapy methods can reduce side effects and improve therapeutic efficacy. Here, we discuss the roles of NO, CO, H₂S and H₂ in cancer biology. Considering the rapidly developing nanotechnology, gas-generating nanoplatforms which can achieve targeted delivery and controlled release were also discussed. Finally, we highlight the current challenges and future opportunities of gas-based cancer therapy.

Effects of different ischemic preconditioning strategies on physiological and cellular mechanisms of intestinal ischemia/reperfusion injury: Implication from an isolated perfused rat small intestine model

Background

Intestinal ischemia/reperfusion (I/R)-injury often results in sepsis and organ failure and is of major importance in the clinic. A potential strategy to reduce I/R-injury is the application of ischemic preconditioning (IPC) during which repeated, brief episodes of I/R are applied. The aim of this study was to evaluate physiological and cellular effects of intestinal I/R-injury and to compare the influence of in-vivo IPC (iIPC) with ex-vivo IPC (eIPC), in which blood derived factors and nerval regulations are excluded.

Methods

Using an established perfused rat intestine model, effects of iIPC and eIPC on physiological as well as cellular mechanisms of I/R-injury (60 min hypoxia, 30 min reperfusion) were investigated. iIPC was applied by three reversible occlusions of the mesenteric artery in-vivo for 5 min followed by 5 min of reperfusion before isolating the small intestine, eIPC was induced by stopping the vascular perfusion ex-vivo 3 times for 5 min followed by 5 min of reperfusion after isolation of the intestine. Study groups (each N = 8–9 animals) were: iIPC, eIPC, I/R (iIPC group), I/R (eIPC group), iIPC+I/R, eIPC+I/R, no intervention/control (iIPC group), no intervention/control (eIPC group). Tissue morphology/damage, metabolic functions, fluid shifts and barrier permeability were evaluated. Cellular mechanisms were investigated using signaling arrays.

Results

I/R-injury decreased intestinal galactose uptake (iIPC group: p<0.001), increased vascular perfusion pressure (iIPC group: p<0.001; eIPC group: p<0.01) and attenuated venous flow (iIPC group: p<0.05) while lactate-to-pyruvate ratio (iIPC group, eIPC group: p<0.001), luminal flow (iIPC group: p<0.001; eIPC group: p<0.05), goblet cell ratio (iIPC group, eIPC group: p<0.001) and apoptosis (iIPC group, eIPC group: p<0.05) were all increased. Application of iIPC prior to I/R increased vascular galactose uptake (P<0.05) while eIPC had no significant impact on parameters of I/R-injury. On cellular level, I/R-injury resulted in a reduction of the phosphorylation of several MAPK signaling molecules. Application of iIPC prior to I/R increased phosphorylation of JNK2 and p38δ while eIPC enhanced CREB and GSK-3α/β phosphorylation.

Conclusion

Intestinal I/R-injury is associated with major physiological and cellular changes. However, the overall influence of the two different IPC strategies on the acute phase of intestinal I/R-injury is rather limited.

Hydrogen therapy can be used to control tumor progression and alleviate the adverse events of medications in patients with advanced non-small cell lung cancer

Chemotherapy, targeted therapy, and immunotherapy are used against advanced non-small cell lung cancer. A clinically efficacious method for relieving the adverse events associated of such therapies is lacking. Fifty-eight adult patients were enrolled in our trial to relieve pulmonary symptoms or the adverse events of drugs. Twenty patients who refused drug treatment were assigned equally and randomly to a hydrogen (H₂)-only group and a control group. According to the results of tumor-gene mutations and drug-sensitivity tests, 10, 18, and 10 patients were enrolled into chemotherapy, targeted therapy, and immunotherapy groups in which these therapies were combined with H₂-therapy, respectively. Patients underwent H₂ inhalation for 4–5 hours per day for 5 months or stopped when cancer recurrence. Before study initiation, the demographics (except for tumor-mutation genes) and pulmonary symptoms (except for moderate cough) of the five groups showed no significant difference. During the first 5 months of treatment, the prevalence of symptoms of the control group increased gradually, whereas that of the four treatment groups decreased gradually. After 16 months of follow-up, progression-free survival of the control group was lower than that of the H₂-only group, and significantly lower than that of H₂ + chemotherapy, H₂ + targeted therapy, and H₂ + immunotherapy groups. In the combined-therapy groups, most drug-associated adverse events decreased gradually or even disappeared. H₂ inhalation was first discovered in the clinic that can be used to control tumor progression and alleviate the adverse events of medications for patients with advanced non-small cell lung cancer. This study was approved by the Ethics Committee of Fuda Cancer Hospital of Jinan University on December 7, 2018 (approval No. Fuda20181207), and was registered at ClinicalTrials.gov (Identifier: NCT03818347) on January 28, 2019.

MicroRNA files in the prevention of intestinal ischemia/reperfusion injury by hydrogen rich saline

Background: Hydrogen-rich saline (HRS) has been proven effective against ischemia/reperfusion (I/R) injury. However, knowledge on the underlying signaling events remain poor. Having recent highlight of microRNAs (miRNAs) in mediating intestinal I/R injury, we hypothesized that HRS may protect intestine against I/R injury by regulating miRNAs.

Method: Mice were given intraperitoneal injection of saline or HRS once daily for five consecutive days before undergoing intestinal I/R that was induced by 60-min ischemia followed by 180-min reperfusion of superior mesenteric artery. The intestine was collected for histopathological assay, miRNA microarray profiling, Real-Time PCR, and Western blotting. Next, miR-199a-3p mimics or inhibitors were transfected into IEC-6 cells to explore the relationship between HRS treatment and miR-199a-3p.

Results: I/R-induced mucosal injury and epithelial cells apoptosis were attenuated by HRS pretreatment. A total of 64 intestinal I/R-responsive miRNAs were altered significantly by HRS pretreatment, in which we validated four novel miRNAs with top significance by Real-Time PCR, namely miR-199a-3p, miR-296-5p, miR-5126, and miR-6538. Particularly, miR-199a-3p was drastically increased by I/R but reduced by HRS. Computational analysis predicts insulin-like growth factor (IGF)-1, mammalian target of rapamycin (mTOR), and phosphoinositide-3-kinase (PI3K) regulatory subunit 1 as targets of miR-199a-3p, suggesting involvement of the pro-survival pathway, IGF- 1/PI3K/Akt/mTOR. In in vitro experiment, HRS treatment reduced miR-199a-3p level, increase IGF-1, PI3K and mTOR mRNA expression, restore IEC-6 cells viability, and this protective effects were reversed under miR-199a-3p mimics treatment.

Conclusion: Collectively, miR-199a-3p may serve a key role in the anti-apoptotic mechanism of HRS that contributes to its protection of the intestine against I/R injury.

Hydrogen-rich saline protects intestinal epithelial tight junction barrier in rats with intestinal ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress-induced apoptosis pathway

AIM

To investigate the effects of hydrogen-rich saline (HRS) on intestinal epithelial tight junction (TJ) barrier in rats with intestinal ischemia-reperfusion injury (IIRI).

MATERIALS AND METHODS

Thirty-two healthy male Sprague-Dawley (SD) rats were randomly divided into four groups (n = 8 each): Sham group, I/R group, HRS group and 4-PBA group. After 45 min of ischemia and 6 h of reperfusion, the rats were sacrificed to collect serum and ileum for detection. Hematoxylin and eosin (H&E) staining was used to observe the morphology of small intestine. The serum expression levels of intestinal fatty acid binding protein (IFABP), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were determined by enzyme linked immunosorbent assay (ELISA). Imunohistochemistry, immunofluorescence and Western blot were used to detect key proteins in intestinal epithelial TJs, ERS, and ERS-induced apoptosis, including occludin, zonula occludens-1 (ZO-1), glucose-regulated protein 78 (GRP78), X-box binding protein-1 (XBP1), C/EBP-homologous protein (CHOP) and caspase-3. Data was presented as mean ± SEM and compared using one-way ANOVA. A p-value <0.05 was considered significant.

RESULTS

Compared with rats in the I/R group, the Chiu score of ileum damage in the HRS group and 4-PBA group were lower. The levels of serum IFABP, TNF-α, and IL-1β were statistically significant among the groups. Increased expression of TJ proteins occludin and ZO-1 by reducing various parameters of ERS and ERS-induced apoptosis evidenced by down-regulation of the protein levels of GRP78, XBP1, CHOP and caspase-3 were shown in the HRS and 4-PBA groups.

CONCLUSION

HRS had potential protective effects on intestinal barrier in IIRI rats. This study suggested that inhibition of excessive ERS and ERS-induced apoptosis by HRS may reduce intestinal epithelial cells damage and maintain the integrity of intestinal epithelial TJ barrier in rats with IIRI.

The effects of hydrogen-rich saline solution on intestinal anastomosis performed after intestinal ischemia reperfusion injury

AIM

We investigated the effects of hydrogen-rich saline solution (HRSS) on intestinal anastomosis performed after intestinal ischemia reperfusion injury (IRI).

MATERIALS AND METHODS

Thirty Wistar albino female rats were randomly divided into five groups. Only laparotomy was performed in the Sham group. In the other four groups, an intestinal IRI was performed for 45 min by clamping the superior mesenteric artery. After intestinal IRI, anastomosis was performed by cutting the intestine from the proximal 15 cm of the ileocecal valve at the first and 24th hours. HRSS was given intraperitoneally 5 ml/kg before reperfusion and for four more days in the HRSS¹ and HRSS²⁴groups, while no treatment was given to the I/R¹ and I/R²⁴ groups. After 5 days, all groups underwent relaparotomy. The anastomotic bursting pressures were measured in all groups, except the Sham group. The tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), myeloperoxidase (MPO) and malondialdehyde (MDA) levels were measured in the tissues taken from the anastomosis line. The tissue sections were evaluated histopathologically and the apoptosis index was determined by applying the TUNEL method. The results were analyzed one-way analysis of variance (ANOVA) and Pearson's chi-squared test.

RESULTS

Although the MPO, MDA, IL-6 and TNF-α tissue values were not statistically significant among the groups, the degree of tissue damage and apoptosis levels were lower and the anastomotic bursting pressures values were higher in the HRSS¹ and HRSS²⁴ groups compared to the I/R¹ and I/R²⁴ groups.

CONCLUSION

HRSS is effective in reducing the intestinal damage caused by an IRI: HRSS has the potential to reduce the detrimental effects of intestinal anastomosis performed after an intestinal IRI.

Hydrogen-rich water reduces inflammatory responses and prevents apoptosis of peripheral blood cells in healthy adults: a randomized, double-blind, controlled trial

The evidence for the beneficial effects of drinking hydrogen-water (HW) is rare. We aimed to investigate the effects of HW consumption on oxidative stress and immune functions in healthy adults using systemic approaches of biochemical, cellular, and molecular nutrition. In a randomized, double-blind, placebo-controlled study, healthy adults (20–59 y) consumed either 1.5 L/d of HW (n = 20) or plain water (PW, n = 18) for 4 weeks. The changes from baseline to the 4th week in serum biological antioxidant potential (BAP), derivatives of reactive oxygen, and 8-Oxo-2′-deoxyguanosine did not differ between groups; however, in those aged ≥ 30 y, BAP increased greater in the HW group than the PW group. Apoptosis of peripheral blood mononuclear cells (PBMCs) was significantly less in the HW group. Flow cytometry analysis of CD4⁺, CD8⁺, CD20⁺, CD14⁺ and CD11b⁺ cells showed that the frequency of CD14⁺ cells decreased in the HW group. RNA-sequencing analysis of PBMCs demonstrated that the transcriptomes of the HW group were clearly distinguished from those of the PW group. Most notably, transcriptional networks of inflammatory responses and NF-κB signaling were significantly down-regulated in the HW group. These finding suggest HW increases antioxidant capacity thereby reducing inflammatory responses in healthy adults.

Amelioration of Coagulation Disorders and Inflammation by Hydrogen-Rich Solution Reduces Intestinal Ischemia/Reperfusion Injury in Rats through NF-κB/NLRP3 Pathway

Intestinal ischemia/reperfusion (I/R) injury often causes inflammatory responses and coagulation disorders, which is further promoting the deterioration of the disease. Hydrogen has anti-inflammatory, antioxidative, and antiapoptotic properties against various diseases. However, the effect of hydrogen on coagulation dysfunction after intestinal I/R and the underlying mechanism remains unclear. The purpose of this study was to explore whether hydrogen-rich solution (HRS) could attenuate coagulation disorders and inflammation to improve intestinal injury and poor survival following intestinal I/R. The rat model of intestinal I/R injury was established by clamping the superior mesenteric artery for 90 min and reperfusion for 2 h. HRS (10 or 20 mL/kg) or 20 mL/kg 0.9% normal saline was intravenously injected at 10 min before reperfusion, respectively. The samples were harvested at 2 h after reperfusion for further analyses. Moreover, the survival rate was observed for 24 h. The results showed that HRS improved the survival rate and alleviated serum diamine oxidase activities, intestinal injury, edema, and apoptosis. Interestingly, HRS markedly improved intestinal I/R-mediated coagulation disorders as evidenced by abnormal conventional indicators of coagulation and thromboelastography. Additionally, HRS attenuated inflammatory responses and the elevated tissue factor (TF) and inhibited nuclear factor kappa beta (NF-κB) and nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation in peripheral blood mononuclear cells. Moreover, inflammatory factors and myeloperoxidase were closely associated with TF level. This study thus emphasized upon the amelioration of coagulation disorders and inflammation by HRS as a mechanism to improve intestinal I/R-induced intestinal injury and poor survival, which might be partially related to inhibition of NF-κB/NLRP3 pathway.

Hydrogen attenuates radiation-induced intestinal damage by reducing oxidative stress and inflammatory response

The small intestine is known to be particularly sensitive to radiation, and the major limiting factor of radiotherapy is the gastrointestinal syndrome that subsequently develops after its administration. The detrimental effects of radiation are mostly mediated via the overproduction of reactive oxygen species (ROS), especially the hydroxyl radical (·OH). Because hydrogen is a selective ·OH scavenger, we hypothesized that hydrogen might exert a protective effect against radiation-induced intestinal damage. Herein, radiation models were built both in mice and in an intestinal crypt epithelial cell (IEC-6) line. In the animal experiment, we demonstrated that hydrogen-rich saline significantly reduced radiation-induced intestinal mucosal damage, improved intestinal function, and increased the survival rate. In addition, radiation-induced oxidative stress damage and systemic inflammatory response were also mitigated by hydrogen treatment. Moreover, hydrogen treatment decreased cell apoptosis and maintained intestinal epithelial cell proliferation in mice. In vitro experiments using the IEC-6 cell line showed that hydrogen-rich medium significantly inhibited ROS formation, maintained cell viability, and inhibited cell apoptosis. Importantly, hydrogen treatment prevented mitochondrial depolarization, cytochrome c release, and activity of caspase-3, caspase-9, and PARP. Moreover, the decreased expression of Bcl-xl and Bcl-2 and the increased expression of Bax protein were also blocked by hydrogen treatment. In conclusion, our study concurrently demonstrated that hydrogen provides an obviously protective effect on radiation-induced intestinal and cell injuries. Our work demonstrated that this protective effect might be due to the blockage of the mitochondrial apoptotic pathway.

Pathological Features of Free Graft and Pedicled Flap in the Nasal Cavity: An Animal Study

OBJECTIVES/HYPOTHESIS

Recent developments in reconstructive techniques for mucosal defects using mucoperiosteal materials have enabled rapid recovery of physiological function after endoscopic sinus surgery. Clinical trials have described the advantages, disadvantages, and different outcomes of free graft and pedicled flap, which, respectively, sacrifice or preserve blood flow. However, histological changes, that affect the postoperative outcomes after reconstruction, remain unclear. We created an animal model for the reconstruction of mucosal defects using free grafts and pedicled flaps, and evaluated them histologically.

STUDY DESIGN

Animal study.

METHODS

We created mucosal defects in the left nasal septum of 20 rabbits and performed reconstruction with free grafts and pedicled flaps. The distribution of ciliary and goblet cells at the reconstruction site was evaluated after 7 and 28 days using hematoxylin and eosin-stained sections to calculate the Ciliary Cell Index and Goblet Cell Index. The severity of inflammation was assessed using the Cartilage Inflammatory Cell Score.

RESULTS

Crusting and changes in the mucosal morphology at the reconstruction site occurred only in the free graft group. In addition, the pedicled flap group had significantly greater preservation of ciliary and goblet cells and less inflammatory cell infiltration into the septal cartilage (P < .05) than the free graft group.

CONCLUSIONS

After reconstruction procedures for mucosal defects, histopathological differences were observed between the free graft and pedicled flap. Reconstruction with pedicled flaps had advantages including preservation of healthy mucosal epithelium and suppression of inflammation on the reconstruction site. This indicated that reconstruction with pedicled flaps might have advantages over that with free grafts.

LEVEL OF EVIDENCE

NA Laryngoscope, 131:E428-E433, 2021.

Hydrogen inhibits endometrial cancer growth via a ROS/NLRP3/caspase-1/GSDMD-mediated pyroptotic pathway

BACKGROUND

Pyroptosis belongs to a novel inflammatory programmed cell death pathway, with the possible prognosis of endometrial cancer related to the terminal protein GSDMD. Hydrogen exerts a biphasic effect on cancer by promoting tumor cell death and protecting normal cells, which might initiate GSDMD pathway-mediated pyroptosis.

METHODS

We performed immunohistochemical staining and western immunoblotting analysis to observe expression of NLRP3, caspase-1, and GSDMD in human and xenograft mice endometrial cancer tissue and cell lines. We investigated treatment with hydrogen could boost ROS accumulation in endometrial cancer cells by intracellular and mitochondrial sources. GSDMD shRNA lentivirus was used to transfect endometrial cancer cells to investigate the function of GSDMD protein in pyroptosis. Propidium iodide (PI) staining, TUNEL assay, measurement of lactate dehydrogenase (LDH) release and IL-1β ELISA were used to analysis pyroptosis between hydrogen-supplemented or normal culture medium. We conducted in vivo human endometrial tumor xenograft mice model to observe anti-tumor effect in hydrogen supplementation.

RESULTS

We observed overexpression of NLRP3, caspase-1, and GSDMD in human endometrial cancer and cell lines by IHC and western immunoblotting. Hydrogen pretreatment upregulated ROS and the expression of pyroptosis-related proteins, and increased the number of PI- and TUNEL-positive cells, as well as the release of LDH and IL-1β, however, GSDMD depletion reduced their release. We further demonstrated that hydrogen supplementation in mice was sufficient for the anti-tumor effect to inhibit xenograft volume and weight of endometrial tumors, as mice subjected to hydrogen-rich water displayed decreased radiance. Tumor tissue sections in the HRW groups presented moderate-to-strong positive expression of NLRP3, caspase-1 and GSDMD. Hydrogen attenuated tumor volume and weight in a xenograft mouse model though the pyroptotic pathway.

CONCLUSIONS

This study extended our original analysis of the ability of hydrogen to stimulate NLRP3 inflammasome/GSDMD activation in pyroptosis and revealed possible mechanism (s) for improvement of anti-tumor effects in the clinical management of endometrial cancer.

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

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

Comparative analysis of isoform-specific and non-selective histone deacetylase inhibitors in attenuating the intestinal damage after hemorrhagic shock

BACKGROUND

Isoform-specific histone deacetylase inhibitors (HDACIs) MC1568 and ACY1083 are comparable to the non-selective HDACI valproic acid (VPA) in improving survival in rodents undergoing lethal hemorrhage. However, the organ-specific properties of isoform-specific HDACIs have not been fully evaluated. Also, whether they can act synergistically is not known. We hypothesized that isoform-specific HDACIs are superior to VPA in attenuating intestinal injury and act synergistically when coadministered.

METHODS

Sprague Dawley rats were hemorrhaged (40% of total blood volume) and randomized to receive (n=4 per group) (1) MC1568 (5 mg/kg), (2) ACY1083 (30 mg/kg), (3) MC1568+ACY1083 (combination: 5 mg/kg + 30 mg/kg, respectively), (4) VPA (250 mg/kg), or (5) normal saline (NS; vehicle; 250 μL). Animals were observed for 3 hours, after which blood samples were collected and samples of the ileum were harvested. Expression of interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and cytokine-induced neutrophil chemoattractant 1 (CINC-1) was assessed in the tissues using enzyme-linked immunosorbent assay. Intestinal cleaved caspase 3 (c-caspase 3) levels were assessed as a marker of apoptosis, and histologic sections of the ileum were examined for signs of bowel injury. Levels of IL-1β and TNF-α were also measured in the serum as global markers of inflammation.

RESULTS

Treatments with MC1568, ACY1083, MC1568+ACY1083, and VPA were associated with decreased IL-1β levels in the intestine and serum compared with NS. IL-1β and TNF-α levels were significantly lower in the ACY1083 group compared with the VPA group. CINC-1 levels were significantly lower in the isoform-specific HDACI groups compared with the NS; however, no significant differences were seen with VPA. All treatment groups had a lower expression of intestinal c-caspase 3 compared with NS. Furthermore, MC1568 and ACY1083 groups had lower apoptosis compared with the VPA group. Bowel injury scores were significantly lower in the isoform-specific HDACI groups compared with the NS group; however, the attenuation in the VPA-treated animals did not reach statistical significance.

DISCUSSION

Isoform-specific HDACIs provide superior intestinal protection compared with VPA in a rodent model of hemorrhagic shock.

LEVEL OF EVIDENCE

Preclinical study.

Myalgic encephalomyelitis/chronic fatigue syndrome: From pathophysiological insights to novel therapeutic opportunities

Myalgic encephalomyelitis (ME) or chronic fatigue syndrome (CFS) is a common and disabling condition with a paucity of effective and evidence-based therapies, reflecting a major unmet need. Cognitive behavioural therapy and graded exercise are of modest benefit for only some ME/CFS patients, and many sufferers report aggravation of symptoms of fatigue with exercise. The presence of a multiplicity of pathophysiological abnormalities in at least the subgroup of people with ME/CFS diagnosed with the current international consensus "Fukuda" criteria, points to numerous potential therapeutic targets. Such abnormalities include extensive data showing that at least a subgroup has a pro-inflammatory state, increased oxidative and nitrosative stress, disruption of gut mucosal barriers and mitochondrial dysfunction together with dysregulated bioenergetics. In this paper, these pathways are summarised, and data regarding promising therapeutic options that target these pathways are highlighted; they include coenzyme Q₁₀, melatonin, curcumin, molecular hydrogen and N-acetylcysteine. These data are promising yet preliminary, suggesting hopeful avenues to address this major unmet burden of illness.

Micro/Nanomaterials-Augmented Hydrogen Therapy

Hydrogen therapy is an emerging and promising therapy strategy of using molecular hydrogen as a new type of safe and effective therapeutic agent, exhibiting remarkable therapeutic effects on many oxidative stress-/inflammation-related diseases owing to its bio-reductivity and homeostatic regulation ability. Different from other gaseous transmitters such as NO, CO, and H₂ S, hydrogen gas has no blood poisoning risk at high concentration because it does not affect the oxygen-carrying behavior of blood red cells. Hydrogen molecules also have low aqueous solubility and high but aimless diffusibility, causing limited therapy efficacy in many diseases. To realize the site-specific hydrogen delivery, controlled hydrogen release and combined therapy is significant but still challenging. Here, a concept of hydrogen nanomedicine to address the issues of hydrogen medicine by using functional micro/nanomaterials for augmented hydrogen therapy is proposed. In this review, various strategies of micro/nanomaterials-augmented hydrogen therapy, including micro/nanomaterials-mediated targeted hydrogen delivery, controlled hydrogen release, and nanocatalytic and multimodel enhancement of hydrogen therapy efficacy, are summarized, which can open a new window for treatment of inflammation-related diseases.

Protective role of heme oxygenase-1 in fatty liver ischemia-reperfusion injury

Ischemia-reperfusion (IR) injury is a kind of injury resulting from the restoration of the blood supply after blood vessel closure during liver transplantation and is the main cause of graft failure. The pathophysiological mechanisms of hepatic IR include a variety of oxidative stress responses. Hepatic IR is characterized by ischemia and hypoxia inducing oxidative stress, immune response and apoptosis. Fat-denatured livers are also used as donors due to the lack of liver donors. Fatty liver is less tolerant to IR than normal liver. Heme oxygenase (HO) is an enzyme that breaks down hemoglobin to bilirubin, ferrous iron and carbon monoxide (CO). Inducible HO subtype HO-1 is an important protective molecule in mammalian cells used to improve acute and chronic liver injury owing to its characteristic anti-inflammatory and anti-apoptotic qualities. HO-1 degrades heme, and its reaction product CO has been shown to reduce hepatic IR injury and increase the survival rate of grafts. As an induced form of HO, HO-1 also exerts a protective effect against liver IR injury and may be useful as a new strategy of ameliorating this kind of damage. This review summarizes the protective effects of HO-1 in liver IR injury, especially in fatty liver.

Supplementation with hydrogen-producing composition confers beneficial effects on physiology and life span in Drosophila

Recently, molecular hydrogen (H₂) has become known as a new class of antioxidants and redox-modulating interventions. Effects of H₂ have been documented for many acute and chronic pathological conditions. The present study was aimed at determining the effect of hydrogen on the physiology and longevity of Drosophila. The flies were given a patented food supplement consisting of a mixture of inert salts with metallic magnesium, which reacted with acidic aqueous solutions, thereby releasing hydrogen gas. The supplementation with hydrogen-rich food prolonged the life span of the wild-type strain. To gain insights into the effect of hydrogen, we used previously generated mutant under-expressing redox-regulating enzymes, peroxiredoxins, in mitochondria. The hydrogen-releasing material lessened the severe shortening of life span of the mutant. Hydrogen also delayed the development of intestinal dysfunction caused by under-expression of peroxiredoxins in the intestinal epithelium. Hydrogen also averted a significant decrease in the mobility of mutant flies that under-expressed peroxiredoxins globally or in specific tissues. Together, the results showed that the introduction of hydrogen to aging or short-lived flies could increase their survival, delay the development of the intestinal barrier dysfunction and significantly improve physical activity.

Acid-responsive H2-releasing Fe nanoparticles for safe and effective cancer therapy

Hydrogen therapy is an emerging and promising strategy for treatment of inflammation-related diseases owing to the excellent bio-safety of hydrogen molecules (H₂), but is facing a challenge that the H₂ concentration at the local disease site is hardly accumulated because of its high diffusibility and low solubility, limiting the efficacy of hydrogen therapy. Herein, we propose a nanomedicine strategy of imaging-guided tumour-targeted delivery and tumour microenvironment-triggered release of H₂ to address this issue, and develop a kind of biocompatible carboxymethyl cellulose (CMC)-coated/stabilized Fe (Fe@CMC) nanoparticle with photoacoustic imaging (PAI), tumour targeting and acid responsive hydrogen release properties for cancer therapy. The Fe@CMC nanoparticles have demonstrated high intratumoural accumulation capability, high acid responsiveness, excellent PAI performance, selective cancer-killing effect and high bio-safety in vitro and in vivo. Effective inhibition of tumour growth is achieved by intravenous injection of the Fe@CMC nanoparticles, and the selective anti-cancer mechanism of Fe@CMC is discovered to be originated from the energy metabolism homeostasis regulatory function of the released H₂. The proposed nanomedicine-mediated hydrogen therapy strategy will open a new window for precise, high-efficacy and safe cancer treatment.

Morphological and molecular response of small intestine to lactulose and hydrogen-rich water in female piglets fed Fusarium mycotoxins contaminated diet

Background

Following the intake of Fusarium mycotoxin-contaminated feed, small intestines may be exposed to high levels of toxic substances that can potentially damage intestinal functions in livestock. It is well known that Fusarium mycotoxins will lead a breakdown of the normally impeccable epithelial barrier, resulting in the development of a “leaky” gut. H₂ administration with different methods has been proved definitely potentials to prevent serious intestinal diseases. The goal of this study is to investigate the roles of lactulose (LAC) and hydrogen-rich water (HRW) in preventing intestinal dysfunction in piglets fed Fusarium mycotoxin-contaminated feed.

Methods

A total of 24 female piglets were evenly assigned to 4 groups: negative control (NC) group, mycotoxin-contaminated (MC) feed group, MC feed with LAC treatment (MC + LAC), and MC feed with HRW treatment (MC + HRW), respectively. Piglets in the NC group were fed uncontaminated control diet, while remaining piglets were fed Fusarium mycotoxin-contaminated diet. For the NC and MC groups, 10 mL/kg body weight (BW) of hydrogen-free water (HFW) was orally administrated to piglets twice daily; while in the MC + LAC and MC + HRW groups, piglets were treated with the same dose of LAC solution (500 mg/kg BW) and HRW twice daily, respectively. On d 25, serum was collected and used for biochemical analysis. Intestinal tissues were sampled for morphological examination as well as relative genes and protein expression analysis.

Results

Our data showed that Fusarium mycotoxins induced higher serum diamine oxidase (DAO) activities (P < 0.05), D-lactic acid levels (P < 0.01), and endotoxin status (P < 0.01), lower villus height (P < 0.01) and ratio of villus height to crypt depth (P < 0.05) in small intestine, greater apoptosis index and higher mRNA expression related to tight junctions (P < 0.05). In addition, the distribution and down-regulation of claudin-3 (CLDN3) protein in the small intestinal was also observed. As expected, oral administrations of HRW and LAC were found to remarkably provide beneficial effects against Fusarium mycotoxin-induced apoptosis and intestinal leaking. Moreover, either HRW or LAC treatments were also revealed to prevent abnormal intestinal morphological changes, disintegrate tight junctions, and restore the expression and distribution of CLDN3 protein in the small intestinal mucosal layer in female piglets that were fed Fusarium mycotoxins contaminated diet.

Conclusions

Our data suggest that orally administrations of HRW and LAC result in less Fusarium mycotoxin-induced apoptosis and leak in the small intestine. Either HRW or LAC treatments could prevent the abnormal changes of intestinal morphology and molecular response of tight junctions as well as restore the distribution and expression of CLDN3 protein of small intestinal mucosa layer in female piglets that were fed Fusarium mycotoxins contaminated diet.

Electronic supplementary material

The online version of this article (10.1186/s40104-019-0320-2) contains supplementary material, which is available to authorized users.

Hydrogen-rich water ameliorates rat placental stress induced by water restriction

Dehydration is one of the intrauterine abnormalities that could lead to fetal growth retardation and to increase the risk of a variety of adult diseases later in life. This study were to determine the impact of hydrogen-rich water (HRW) supplementation on placental angiotensin II type 1 receptor and placental oxidative stress induced by water restriction. Pregnant Wistar rat were randomly assigned to one of the three groups (n =12 per group). In control group, pure water and food were supplied ad libitum. Water restriction group and HRW group were respectively given pure water and HRW with free access to food, excepting only one hour was available for drinking from day 7 to day 17 of pregnancy. The placental damages and biomarkers of stress were detected by histopathology, immunohistochemistry and western blot, as well as serological test were performed. We demonstrated that maternal water restriction resulted in reduced urine volume and increased serum osmotic pressure, along with decreased fetus weight and crown-rump length. Although placental weight and the number of fetuses had no significant difference among groups, the placental efficiency significantly increased after the oral administration of HRW to the mothers. Meanwhile, the serological derivatives of reactive oxygen metabolites decreased, a significant improvement of placental microstructure with more developed junctional zone and denser labyrinth was manifested, the upregulated expression of angiotensin II type 1 receptor, nuclear factoκB, malondialdehyde, 8-hydroxydeoxyguanosine, p38, c-Jun N-terminal kinase and down-regulation of superoxide dismutase were revealed in the placenta. Collectively, HRW administration is able to effectively attenuate placental stress induced by water restriction.

Molecular hydrogen protects against ischemia-reperfusion injury in a mouse fatty liver model via regulating HO-1 and Sirt1 expression

Fatty liver has lower tolerance against ischemia-reperfusion (I/R) injury in liver operations, including liver transplantation. Seeking to ameliorate liver injury following I/R in fatty liver, we examined the protective effect of hydrogen (H₂) saline on I/R liver injury in a methionine and choline-deficient plus high fat (MCDHF) diet-induced fatty liver mouse model. Saline containing 7 ppm H₂ was administrated during the process of I/R. Livers were obtained and analyzed. Primary hepatocytes and Kupffer cells (KCs) were obtained from fatty liver and subjected to hypoxia/reoxygenation. Apoptosis-related proteins and components of the signaling pathway were analyzed after treatment with hydrogen gas. The MCDHF I/R group showed higher levels of AST and ALT in serum, TUNEL-positive apoptotic cells, F4/80 immunopositive cells, mRNA levels of inflammatory cytokines, constituents of the signaling pathway, pro-apoptotic molecules in liver, and KCs and/or primary hepatocytes, compared to the control group. In contrast, H₂ treatment significantly suppressed the signs of I/R injury in fatty liver. Moreover, the expression of Bcl-2, HO-1, and Sirt1 in liver, KCs, and hepatocytes by hydrogen gas were increased, whereas caspase activation, Bax, and acetylation of p53 were suppressed by hydrogen gas. These results demonstrated that H₂ treatment ameliorated I/R liver injury in a fatty liver model by reducing hepatocyte apoptosis, inhibiting macrophage activation and inflammatory cytokines, and inducing HO-1 and Sirt1 expression. Taken togather, treatment with H₂ saline may have a protective effect and safe therapeutic activity during I/R events, such as in liver transplantation with fatty liver.

Early Aerobic Exercise Combined with Hydrogen-Rich Saline as Preconditioning Protects Myocardial Injury Induced by Acute Myocardial Infarction in Rats

It has been reported that hydrogen-rich saline (HRS) water reduces oxidative stress, and early aerobic exercise (eAE) acts an efficient exercise preconditioning (EP) against cardiac I/R injury. However, whether early aerobic exercise combined with hydrogen-rich saline (eAE-HRS) water can more effectively protect myocardial damage induced by acute myocardial infarction (MI) is still unknown. This study was aimed to evaluate the effect of eAE-HRS in preventing MI-induced myocardial damage and explore the possible underlying mechanisms. After Sprague-Dawley (SD) rats were given a intragastric administration of HRS (1.6 ppm) at a dosage of 10 mL/kg weight daily for 3 weeks and/or the SD rats were performed a eAE program with 3 weeks running training, the left anterior descending coronary artery was ligated to induce MI. We assessed the effects of eAE-HRS on myocardial injury and oxidative damage in the MI model of rats and detected the effects of eAE-HRS on the expressions of cardiac OGG1 and Tom40, Tom20, and Tim23. The eAE-HRS increased significantly left ventricular systolic pressure, reduced left ventricular end-diastolic pressure, and potentiated + dp/dt_max, -dp/dt_max, heart coefficient and pH after MI injury. The eAE-HRS reduced MI-induced CK-MB level, c-Tnl level, h-FABP level, infarct size. The eAE-HRS enhanced MI-induced levels of the superoxide dismutase and total antioxidant capacity, attenuated MI-induced levels of malondialdehyde and catalase. The eAE-HRS increased expressions of OGG1, Tom20 and Tim23 proteins after MI injury, but not Tom40. The eAE-HRS has the potential to be a novel precautionary measure to protect myocardial injury after MI via partially regulating expressions of antioxidant-related proteins and mitochondrial-associated proteins.

Post-reperfusion hydrogen gas treatment ameliorates ischemia reperfusion injury in rat livers from donors after cardiac death: a preliminary study

BACKGROUND AND PURPOSE

We reported previously that hydrogen gas (H₂) reduced hepatic ischemia and reperfusion injury (IRI) after prolonged cold storage (CS) of livers retrieved from heart-beating donors. The present study was designed to assess whether H₂ reduced hepatic IRI during donation of a cardiac death (DCD) graft with subsequent CS.

METHODS

Rat livers were harvested after 30-min cardiac arrest and stored for 4 h in University of Wisconsin solution. The graft was reperfused with oxygenated buffer, with or without H₂ (H₂ or NT groups, respectively), at 37° for 90 min on isolated perfused rat liver apparatus.

RESULTS

In the NT group, liver enzyme leakage, apoptosis, necrosis, energy depletion, redox status, impaired microcirculation, and bile production were indicative of severe IRI, whereas in the H₂ group these impairments were significantly suppressed. The phosphorylation of cytoplasmic MKK4 and JNK were enhanced in the NT group and suppressed in the H₂ group. NFkB-p65 and c-Fos in the nucleus were unexpectedly unchanged by IRI regardless of H₂ treatment, indicating the absence of inflammation in this model.

CONCLUSION

H₂ was observed to ameliorate IRI in the DCD liver by maintaining microcirculation, mitochondrial functions, and redox status, as well as suppressing the cytoplasmic MKK4-JNK-mediated cellular death pathway.

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

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

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

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

Intestinal Microbiota Ecological Response to Oral Administrations of Hydrogen-Rich Water and Lactulose in Female Piglets Fed a Fusarium Toxin-Contaminated Diet

The objective of the current experiment was to explore the intestinal microbiota ecological response to oral administrations of hydrogen-rich water (HRW) and lactulose (LAC) in female piglets fed a Fusarium mycotoxin-contaminated diet. A total of 24 individually-housed female piglets (Landrace × large × white; initial average body weight, 7.25 ± 1.02 kg) were randomly assigned to receive four treatments (six pigs/treatment): uncontaminated basal diet (negative control, NC), mycotoxin-contaminated diet (MC), MC diet + HRW (MC + HRW), and MC diet + LAC (MC + LAC) for 25 days. Hydrogen levels in the mucosa of different intestine segments were measured at the end of the experiment. Fecal scoring and diarrhea rate were recorded every day during the whole period of the experiment. Short-chain fatty acids (SCFAs) profiles in the digesta of the foregut and hindgut samples were assayed. The populations of selected bacteria and denaturing gradient gel electrophoresis (DGGE) profiles of total bacteria and methanogenic Archaea were also evaluated. Results showed that Fusarium mycotoxins not only reduced the hydrogen levels in the caecum but also shifted the SCFAs production, and populations and communities of microbiota. HRW treatment increased the hydrogen levels of the stomach and duodenum. HRW and LAC groups also had higher colon and caecum hydrogen levels than the MC group. Both HRW and LAC protected against the mycotoxin-contaminated diet-induced higher diarrhea rate and lower SCFA production in the digesta of the colon and caecum. In addition, the DGGE profile results indicated that HRW and LAC might shift the pathways of hydrogen-utilization bacteria, and change the diversity of intestine microbiota. Moreover, HRW and LAC administrations reversed the mycotoxin-contaminated diet-induced changing of the populations of Escherichia coli (E. coli) and Bifidobacterium in ileum digesta and hydrogen-utilizing bacteria in colon digesta.

Increase in breath hydrogen concentration was correlated with the main pancreatic duct stenosis

BACKGROUND

Hydrogen is produced from unabsorbed carbohydrates in the intestine through degradation and metabolism by hydrogenase of intestinal bacteria. The hydrogen is then partially diffused into blood flow and released and detected in exhaled breath. Pancreatic juice production is decreased in patients with reduced pancreatic exocrine function, including those with pancreatic cancer, thus decreasing digestion and absorption of nutrients including carbohydrates, which may increase undigested carbohydrates in the intestine and increase breath hydrogen concentration (BHC). The aim of this study was to investigate the association between BHC and pancreatic diseases.

METHODS

A retrospective study was designed and 68 patients underwent morning fasting breath hydrogen test. Since there is no clear standard, normal BHC, the median of the measured values from the subjects (9 ppm) was adopted as the standard. The subjects were classified into those with a value exceeding the median (BHC high group: 32 patients) and a value equal to or below the median (BHC low group: 36 patients). Patients characteristics, blood test results and imaging findings characteristic of pancreatic diseases were compared between the groups.

RESULTS

The age was significantly higher (P = 0.010) and the incidences of pancreatic ductal adenocarcinoma and autoimmune pancreatitis were significantly higher (P = 0.018 and P = 0.004, respectively) in the BHC high group. With respect to the blood test items, the Alb level was significantly lower in the BHC high group (P = 0.005). With respect to the characteristic imaging findings of pancreatic diseases, the proportions of patients with pancreatic enlargement, the main pancreatic duct (MPD) stenosis, and the MPD dilatation were significantly higher in the BHC high group (P = 0.022, P < 0.001, and P = 0.002, respectively). On univariate analysis, only the MPD stenosis was extracted as an independent factor (P = 0.014).

CONCLUSION

It was suggested that the fasting BHC is associated with pancreatic diseases causing stenosis of the MPD, including pancreatic cancer (UMIN000020777).

Therapeutic effect of molecular hydrogen in corneal UVB-induced oxidative stress and corneal photodamage

The aim of this study is to examine whether molecular hydrogen (H₂) is able to reduce oxidative stress after corneal damage induced by UVB irradiation. We previously found that UVB irradiation of the cornea caused the imbalance between the antioxidant and prooxidant enzymes in the corneal epithelium, followed by the imbalance between metalloproteinases and their physiological inhibitors (imbalances in favour of prooxidants and metalloproteinases) contributing to oxidative stress and development of the intracorneal inflammation. Here we investigate the effect of H₂ dissolved in PBS in the concentration 0.5 ppm wt/vol, applied on rabbit corneas during UVB irradiation and healing (UVB doses 1.01 J/cm² once daily for four days). Some irradiated corneas remained untreated or buffer treated. In these corneas the oxidative stress appeared, followed by the excessive inflammation. Malondiladehyde and peroxynitrite expressions were present. The corneas healed with scar formation and neovascularization. In contrast, in H₂ treated irradiated corneas oxidative stress was suppressed and malondiladehyde and peroxynitrite expressions were absent. The corneas healed with the restoration of transparency. The study provides the first evidence of the role of H₂ in prevention of oxidative and nitrosative stress in UVB irradiated corneas, which may represent a novel prophylactic approach to corneal photodamage.

Prevention of ischemia-induced hearing loss by intravenous administration of hydrogen-rich saline in gerbil

OBJECTIVE

Hydrogen-rich water, which is a potent antioxidant agent, was investigated for its protective effects against ischemic damage of the cochlea in gerbils.

METHODS

The animals were subjected to transient cochlear ischemia by occluding the bilateral vertebral arteries for l5min. Five milliliters of hydrogen-rich saline was then intravenously administered immediately after the insult. Saline without hydrogen was used as a control. Effects of hydrogen were evaluated using the auditory brainstem response (ABR) and histological studies of the inner ear.

RESULTS

In non-ischemia animals, ABR thresholds and histological findings of the cochlea did not change by administration of saline or hydrogen-rich saline. In contrast, transient cochlear ischemia caused a 24.2±3.8dB increase in the ABR threshold at 8kHz, and a decrease of 14.1%±1.8% in the number of inner hair cells (IHCs) at the basal turn on day 7. Ischemic damage was more severe at 16 and 32kHz. When the animals were treated with hydrogen-rich saline, cochlear damage was significantly reduced: the increase in ABR threshold was 11.7±2.6dB at 8kHz and the IHC loss was 7.5%±2.1% at the basal turn on day 7. The effects of hydrogen-rich saline were more prominent at higher frequencies.

CONCLUSIONS

Intravenous administration of hydrogen-rich saline was effective in preventing acute hearing loss due to transient cochlear ischemia.

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.

Mechanism underlying methyl eugenol attenuation of intestinal ischemia/reperfusion injury

Intestinal ischemia/reperfusion (I/R) injury is associated with a high risk of mortality in the clinical situation. Many factors are involved in I/R, including reactive oxygen species, cytokine release, and apoptosis. We aimed to determine whether a pure methyl eugenol (ME) given before intestinal ischemia, protects against intestinal I/R injury and the possible mechanism involved in this protection. Rat received ME (100 mg/kg) for 30 days then underwent intestinal I/R with 30 min ischemia and 60 min reperfusion. Serum lactate dehydrogenase (LDH) level, tissue malondialdehyde (MDA), as well as some antioxidant biomarkers were assessed, while the serum level of tumor necrosis factor alpha (TNF-α) was determined by ELISA. The change in TNF-α and interleukin 6 (IL-6) gene expressions were evaluated and confirmed by assessing protein level of TNF-α in the intestinal tissue by immunohistochemistry. Apoptosis was evaluated using DNA-laddering assay and by detecting caspase-3 immunohistochemically. Administration of ME prior to I/R injury resulted in a modulation of the production of MDA, LDH, and nitric oxide and restoration of the tested oxidative stress biomarkers. Pretreatment with ME downregulated messenger RNA of TNF-α and IL-6 inflammatory cytokines and their protein expressions in I/R rats. Marked inhibition of the apoptotic DNA and improvement of the architectures of small intestine were observed after pretreatment with ME. ME exhibits a protective effect against intestinal I/R via amelioration of the oxidative stress and inflammatory cytokines gene expression. Therefore, the supplementation of ME prior to intestinal I/R might be helpful in the attenuation of I/R complications.

Protective effects of hydrogen rich water on the intestinal ischemia/reperfusion injury due to intestinal intussusception in a rat model

This study aimed to investigate the protective effects of hydrogen rich water on the intestinal ischemia/reperfusion (I/R) injury in a rat intestinal intussusception (II) model. Ninety Sprague-Dawley rats were randomly assigned into three groups (n = 30 per group). In sham group, rats received laparotomy, and the intestine was exposed for 15 minutes without II. In I/R + saline group and I/R + hydrogen group, rats received II after laparotomy and then intestine was relocated 8 hours later, followed by immediately intraperitoneal injection of normal saline and hydrogen rich water (HRW) (5 mL/kg), respectively. One hour later, the intestine was collected for hematoxylin-eosin staining and immunohistochemistry for apoptotic cells and 8-oxo-deoxyguanosine, and blood was harvested for detection of tumor necrosis factor-α, malondialdehyde and superoxide dismutase. Hematoxylin-eosin staining showed the intestinal mucosa was significantly damaged in I/R + saline group, which was markedly attenuated after HRW treatment. The serum tumor necrosis factor-α content increased significantly in I/R + saline group, but HRW treatment reduced serum tumor necrosis factor-α content as compared to I/R + saline group (P < 0.05). Serum malondialdehyde content and 8-oxo-deoxyguanosine positive cells in the intestine increased dramatically after II, but HRW significantly reduced them in I/R+hydrogen group (P < 0.05). In addition, superoxide dismutase activity reduced markedly and apoptotic cells increased in I/R + saline group as compared to sham group, but they HRW increased superoxide dismutase activity and reduced apoptotic cells significantly in I/R + hydrogen group (P < 0.05). Our results indicate hydrogen rich water is able to attenuate II induced intestinal I/R injury via inhibiting intestinal inflammation, attenuating intestinal/serum oxidative stress and reducing apoptotic intestinal cells.

Saturated hydrogen saline ameliorates lipopolysaccharide-induced acute lung injury by reducing excessive autophagy

The pathogenesis of acute lung injury (ALI) induced by lipopolysaccharide (LPS) involves excessive pulmonary inflammation and oxidative stress. In turn, autophagy is associated with inflammatory diseases and organ dysfunction, and studies have demonstrated that LPS treatment may trigger autophagy. Thus, excessive autophagy may stimulate the strong inflammatory response observed in the development of LPS-induced ALI. Saturated hydrogen saline may alleviate LPS-induced ALI by inhibiting autophagy, however its underlying mechanisms of action remain unknown. It has been suggested that saturated hydrogen saline may downregulate expression of nuclear factor (NF)-κB, leading to a decrease in Beclin-1 transcription and inhibition of autophagy. Inhibition of autophagy also occurs via the phosphorylation of Unc-51-like autophagy activating kinase 1 and autophagy-related protein-13 by mechanistic target of rapamycin, which in turn may be upregulated by saturated hydrogen saline. In addition, signaling pathways involving heme oxygenase-1 and p38 mitogen-activated protein kinase are associated with the alleviative effects of saturated hydrogen saline on LPS-induced autophagy. The present review focuses on potential molecular mechanisms regarding the effects of saturated hydrogen saline in the reduction of autophagy during LPS-induced ALI.

Preventive and therapeutic application of molecular hydrogen in situations with excessive production of free radicals

Excessive production of oxygen free radicals has been regarded as a causative common denominator of many pathological processes in the animal kingdom. Hydroxyl and nitrosyl radicals represent the major cause of the destruction of biomolecules either by a direct reaction or by triggering a chain reaction of free radicals. Scavenging of free radicals may act preventively or therapeutically. A number of substances that preferentially react with free radicals can serve as scavengers, thus increasing the internal capacity/activity of endogenous antioxidants and protecting cells and tissues against oxidative damage. Molecular hydrogen (H(2)) reacts with strong oxidants, such as hydroxyl and nitrosyl radicals, in the cells, that enables utilization of its potential for preventive and therapeutic applications. H(2) rapidly diffuses into tissues and cells without affecting metabolic redox reactions and signaling reactive species. H(2) reduces oxidative stress also by regulating gene expression, and functions as an anti-inflammatory and anti-apoptotic agent. There is a growing body of evidence based on the results of animal experiments and clinical observations that H(2) may represent an effective antioxidant for the prevention of oxidative stress-related diseases. Application of molecular hydrogen in situations with excessive production of free radicals, in particular, hydroxyl and nitrosyl radicals is relatively simple and effective, therefore, it deserves special attention.

Hydrogen gas alleviates oxygen toxicity by reducing hydroxyl radical levels in PC12 cells

Hyperbaric oxygen (HBO) therapy through breathing oxygen at the pressure of above 1 atmosphere absolute (ATA) is useful for varieties of clinical conditions, especially hypoxic-ischemic diseases. Because of generation of reactive oxygen species (ROS), breathing oxygen gas at high pressures can cause oxygen toxicity in the central nervous system, leading to multiple neurological dysfunction, which limits the use of HBO therapy. Studies have shown that Hydrogen gas (H₂) can diminish oxidative stress and effectively reduce active ROS associated with diseases. However, the effect of H₂ on ROS generated from HBO therapy remains unclear. In this study, we investigated the effect of H₂ on ROS during HBO therapy using PC12 cells. PC12 cells cultured in medium were exposed to oxygen gas or mixed oxygen gas and H₂ at 1 ATA or 5 ATA. Cells viability and oxidation products and ROS were determined. The data showed that H₂ promoted the cell viability and inhibited the damage in the cell and mitochondria membrane, reduced the levels of lipid peroxidation and DNA oxidation, and selectively decreased the levels of •OH but not disturbing the levels of O₂^•-, H₂O₂, or NO• in PC12 cells during HBO therapy. These results indicated that H₂ effectively reduced •OH, protected cells against oxygen toxicity resulting from HBO therapy, and had no effect on other ROS. Our data supported that H₂ could be potentially used as an antioxidant during HBO therapy.

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

Hydrogen is a kind of noble gas with the character to selectively neutralize reactive oxygen species. Former researches proved that low-concentration of hydrogen can be used to ameliorating cerebral ischemia/reperfusion injury. Hydrogen electrolyzed from water has a hydrogen concentration of 66.7%, which is much higher than that used in previous studies. And water electrolysis is a potential new hydrogen resource for regular clinical use. This study was designed and carried out for the determination of safety and neuroprotective effects of water electrolysis-derived hydrogen. Sprague-Dawley rats were used as experimental animals, and middle cerebral artery occlusion was used to make cerebral ischemia/reperfusion model. Pathologically, tissues from rats in hydrogen inhalation group showed no significant difference compared with the control group in HE staining pictures. The blood biochemical findings matched the HE staining result. TTC, Nissl, and TUNEL staining showed the significant improvement of infarction volume, neuron morphology, and neuron apoptosis in rat with hydrogen treatment. Biochemically, hydrogen inhalation decreased brain caspase-3, 3-nitrotyrosine and 8-hydroxy-2-deoxyguanosine-positive cells and inflammation factors concentration. Water electrolysis-derived hydrogen inhalation had neuroprotective effects on cerebral ischemia/reperfusion injury in rats with the effect of suppressing oxidative stress and inflammation, and it is a possible new hydrogen resource to electrolyze water at the bedside clinically.

Intraperitoneally administered, hydrogen-rich physiologic solution protects against postoperative ileus and is associated with reduced nitric oxide production

BACKGROUND

Postoperative ileus, a transient impairment of bowel motility initiated by intestinal inflammation, is common after an abdominal operation and leads to increased hospital stays and costs. Hydrogen has potent anti-inflammatory and antioxidant properties and potential therapeutic value. Solubilized hydrogen may be a portable and practical means of administering therapeutic hydrogen gas. We hypothesized that intraperitoneal administration of hydrogen-rich saline would ameliorate postoperative ileus.

METHODS

Ileus was induced via surgical manipulation in mice and rats. The peritoneal cavity was filled with 1.0 mL saline or hydrogen-rich saline (≥1.5-2.0 ppm) before closure of the abdominal incision. Intestinal transit was assessed 24 hours postoperatively. Inflammation was examined by quantitation of neutrophil extravasation and expression of proinflammatory markers. Nitric oxide production was assessed in cultured muscularis propria.

RESULTS

Surgical manipulation resulted in a marked delay in intestinal transit and was associated with upregulation of proinflammatory cytokines and increased neutrophil extravasation. Bowel dysmotility, induced by surgical manipulation and inflammatory events, was significantly attenuated by intra-abdominal administration of hydrogen-rich saline. Nitric oxide production in the muscle layers of the bowel was inhibited by hydrogen treatment.

CONCLUSION

A single intraperitoneal dose of hydrogen-rich saline ameliorates postoperative ileus by inhibiting the inflammatory response and suppressing nitric oxide production.

Disrupted intestinal structure in a rat model of intermittent hypoxia

Obstructive sleep apnea (OSA) is a chronic condition characterized by chronic intermittent hypoxia (IH) and subsequent reoxygenation (ROX). The gastrointestinal system, which is particularly sensitive to tissue hypoxia and reduced perfusion, is likely to be affected by OSA. A rat model of IH was used to analyze oxidative stress-associated genes and tight junction proteins by reverse transcription‑quantitative polymerase chain reaction. Subsequently, altered morphology of the duodenal mucosa and elevated Chiu scores were observed in the IH‑exposed rats. In addition, IH exposure resulted in upregulation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, NADPH oxidase 2 and p22phox, in the small intestine, and upregulation of transcription factors, including hypoxia‑inducible factor-1, nuclear factor‑κB and activator protein-1. Furthermore, the mRNA expression levels of intestinal tight junction (TJ)-related proteins, claudin-1 and claudin-4, were decreased in the IH‑exposed group, as compared with in the control group. In conclusion, the present study demonstrated that OSA, which is characterized by IH and ROX, may lead to disruption of the duodenum. The mechanism underlying the effects of OSA on duodenal morphology may be associated with increased oxidative stress and activation of transcription factors, subsequently inducing intestinal TJ disruption and intestinal injury.