Recent extensive studies have revealed that molecular hydrogen (H2) has great potential for improving oxidative stress‐related diseases by inhaling H2 gas, injecting saline with dissolved H2, or ...drinking water with dissolved H2 (H2‐water); however, little is known about the dynamic movement of H2 in a body. First, we show that hepatic glycogen accumulates H2 after oral administration of H2‐water, explaining why consumption of even a small amount of H2 over a short span time efficiently improves various disease models. This finding was supported by an in vitro experiment in which glycogen solution maintained H2. Next, we examined the benefit of ad libitum drinking H2‐water to type 2 diabetes using db/db obesity model mice lacking the functional leptin receptor. Drinking H2‐water reduced hepatic oxidative stress, and significantly alleviated fatty liver in db/db mice as well as high fat‐diet‐induced fatty liver in wild‐type mice. Long‐term drinking H2‐water significantly controlled fat and body weights, despite no increase in consumption of diet and water. Moreover, drinking H2‐water decreased levels of plasma glucose, insulin, and triglyceride, the effect of which on hyperglycemia was similar to diet restriction. To examine how drinking H2‐water improves obesity and metabolic parameters at the molecular level, we examined gene‐expression profiles, and found enhanced expression of a hepatic hormone, fibroblast growth factor 21 (FGF21), which functions to enhance fatty acid and glucose expenditure. Indeed, H2 stimulated energy metabolism as measured by oxygen consumption. The present results suggest the potential benefit of H2 in improving obesity, diabetes, and metabolic syndrome.
We previously showed that H2 acts as a novel antioxidant to protect cells against oxidative stress. Subsequently, numerous studies have indicated the potential applications of H2 in therapeutic and ...preventive medicine. Moreover, H2 regulates various signal transduction pathways and the expression of many genes. However, the primary targets of H2 in the signal transduction pathways are unknown. Here, we attempted to determine how H2 regulates gene expression. In a pure chemical system, H2 gas (approximately 1%, v/v) suppressed the autoxidation of linoleic acid that proceeds by a free radical chain reaction, and pure 1-palmitoyl-2-arachidonyl-sn-glycero-3-phosphocholine (PAPC), one of the major phospholipids, was autoxidized in the presence or absence of H2. H2 modified the chemical production of the autoxidized phospholipid species in the cell-free system. Exposure of cultured cells to the H2-dependently autoxidized phospholipid species reduced Ca(2+) signal transduction and mediated the expression of various genes as revealed by comprehensive microarray analysis. In the cultured cells, H2 suppressed free radical chain reaction-dependent peroxidation and recovered the increased cellular Ca(2+), resulting in the regulation of Ca(2+)-dependent gene expression. Thus, H2 might regulate gene expression via the Ca(2+) signal transduction pathway by modifying the free radical-dependent generation of oxidized phospholipid mediators.
Molecular hydrogen (H
) was believed to be an inert and nonfunctional molecule in mammalian cells; however, we overturned the concept by reporting the therapeutic effects of H
against oxidative ...stress. Subsequently, extensive studies revealed multiple functions of H
by exhibiting the efficacies of H
in various animal models and clinical studies. Here, we investigated the effect of H
on free-radical-induced cytotoxicity using
-butyl hydroperoxide in a human acute monocytic leukemia cell line, THP-1. Cell membrane permeability was determined using lactate dehydrogenase release assay and Hoechst 33342 and propidium iodide staining. Fatty acid peroxidation and mitochondrial viability were measured using 2 kinds of fluorescent dyes, Liperfluo and C11-BODIPY, and using the alamarBlue assay based on the reduction of resazurin to resorufin by mainly mitochondrial succinate dehydrogenase, respectively. Mitochondrial membrane potential was evaluated using tetramethylrhodamine methyl ester. As a result, H
protected the cultured cells against the cytotoxic effects induced by
-butyl hydroperoxide; H
suppressed cellular fatty acid peroxidation and cell membrane permeability, mitigated the decline in mitochondrial oxidoreductase activity and mitochondrial membrane potential, and protected cells against cell death evaluated using propidium iodide staining. These results suggested that H
suppresses free-radical-induced cell death through protection against fatty acid peroxidation and mitochondrial dysfunction.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
BACKGROUND—We have previously shown that hydrogen (H2) inhalation, begun at the start of hyperoxic cardiopulmonary resuscitation, significantly improves brain and cardiac function in a rat model of ...cardiac arrest. Here, we examine the effectiveness of this therapeutic approach when H2 inhalation is begun on the return of spontaneous circulation (ROSC) under normoxic conditions, either alone or in combination with targeted temperature management (TTM).
METHODS AND RESULTS—Rats were subjected to 6 minutes of ventricular fibrillation cardiac arrest followed by cardiopulmonary resuscitation. Five minutes after achieving ROSC, post–cardiac arrest rats were randomized into 4 groupsmechanically ventilated with 26% O2 and normothermia (control); mechanically ventilated with 26% O2, 1.3% H2, and normothermia (H2); mechanically ventilated with 26% O2 and TTM (TTM); and mechanically ventilated with 26% O2, 1.3% H2, and TTM (TTM+H2). Animal survival rate at 7 days after ROSC was 38.4% in the control group, 71.4% in the H2 and TTM groups, and 85.7% in the TTM+H2 group. Combined therapy of TTM and H2 inhalation was superior to TTM alone in terms of neurological deficit scores at 24, 48, and 72 hours after ROSC, and motor activity at 7 days after ROSC. Neuronal degeneration and microglial activation in a vulnerable brain region was suppressed by both TTM alone and H2 inhalation alone, with the combined therapy of TTM and H2 inhalation being most effective.
CONCLUSIONS—H2 inhalation was beneficial when begun after ROSC, even when delivered in the absence of hyperoxia. Combined TTM and H2 inhalation was more effective than TTM alone.
Immune checkpoint inhibitors are causing a paradigm shift in cancer treatment. Immune checkpoint molecules such as programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein ...4 (CTLA-4) dampen T cell activation to avoid autoimmunity and the destructive effects of an excessive inflammatory response. Immune checkpoint signaling can be exploited by tumors to escape host immune surveillance, and immune checkpoint inhibitors enhance antitumor immunity by releasing the brakes on the immune system. PD-1 was identified in 1992 by Honjo and colleagues at Kyoto University. Studies in animal models revealed that PD-1 blockade can inhibit tumorigenesis and tumor metastasis. In addition, PD-1 blockade showed fewer adverse effects than CTLA-4 blockade. Based on these findings, a humanized monoclonal antibody against human PD-1 called nivolumab was developed. Since PD-1 blockade targets lymphocytes rather than tumor cells, the therapeutic effects last longer, even if mutations occur during tumorigenesis. Furthermore, because it does not depend on specific tumor antigens, PD-1 blockade can be applied to various kinds of tumors.
The aim of this study was to evaluate the efficacy and safety of high-dose taurine supplementation for prevention of stroke-like episodes of MELAS (mitochondrial myopathy, encephalopathy, lactic ...acidosis and stroke-like episodes), a rare genetic disorder caused by point mutations in the mitochondrial DNA that lead to a taurine modification defect at the first anticodon nucleotide of mitochondrial tRNA
, resulting in failure to decode codons accurately.
After the nationwide survey of MELAS, we conducted a multicentre, open-label, phase III trial in which 10 patients with recurrent stroke-like episodes received high-dose taurine (9 g or 12 g per day) for 52 weeks. The primary endpoint was the complete prevention of stroke-like episodes during the evaluation period. The taurine modification rate of mitochondrial tRNA
was measured before and after the trial.
The proportion of patients who reached the primary endpoint (100% responder rate) was 60% (95% CI 26.2% to 87.8%). The 50% responder rate, that is, the number of patients achieving a 50% or greater reduction in frequency of stroke-like episodes, was 80% (95% CI 44.4% to 97.5%). Taurine reduced the annual relapse rate of stroke-like episodes from 2.22 to 0.72 (P=0.001). Five patients showed a significant increase in the taurine modification of mitochondrial tRNA
from peripheral blood leukocytes (P<0.05). No severe adverse events were associated with taurine.
The current study demonstrates that oral taurine supplementation can effectively reduce the recurrence of stroke-like episodes and increase taurine modification in mitochondrial tRNA
in MELAS.
UMIN000011908.
Hematopoietic stem cells (HSCs) emerge from hemogenic endothelium (HE) within the ventral portion of the dorsal aorta during vertebrate development. In zebrafish, Notch signaling induces HE ...specification from posterior lateral plate mesoderm (PLPM) cells as they migrate over the ventral surface of the somite. During migration, PLPM cells make close contact with Notch-ligand-expressing somitic cells to acquire HE identity. Herein, we show in zebrafish that the small GTPase Rap1b regulates HSC development by potentiating Notch-mediated HE specification. PLPM cells migrate toward the midline along the somite boundary where fibronectin accumulates. Rap1b stimulates integrin β1 to enhance PLPM cell adhesion to fibronectin localized at the somite boundary. Rap1b-induced integrin-β1-mediated adhesion to fibronectin leads to the spreading of PLPM cells to facilitate their physical contact with the Notch-ligand-expressing somitic cells, thereby promoting Notch-mediated HE specification. Thus, we have revealed an unexpected role of Rap1-induced integrin-mediated cell adhesion in HSC development.
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•Rap1b is involved in hematopoietic stem cell development in zebrafish•Rap1b promotes Notch-mediated hemogenic endothelium specification of PLPM cells•Fibronectin guides PLPM cells to migrate along somite boundary through integrin β1•Rap1b activates Notch by inducing integrin-β1-mediated PLPM adhesion to somite
Rho et al. show a role for the small GTPase Rap1b in hematopoietic stem cell development in zebrafish. Rap1b promotes Notch-signal-mediated specification of posterior lateral plate mesoderm cells by inducing their adhesion to Notch-ligand-expressing somitic cells through integrin-β1-mediated adhesion to fibronectin localized at the somite boundary.
Molecular hydrogen (H(2)) is an efficient antioxidant that diffuses rapidly across cell membranes, reduces reactive oxygen species (ROS), such as hydroxyl radicals and peroxynitrite, and suppresses ...oxidative stress-induced injury in several organs. ROS have been implicated in radiation-induced damage to lungs. Because prompt elimination of irradiation-induced ROS should protect lung tissue from damaging effects of irradiation, we investigated the possibility that H(2) could serve as a radioprotector in the lung. Cells of the human lung epithelial cell line A549 received 10 Gy irradiation with or without H(2) treatment via H(2)-rich PBS or medium. We studied the possible radioprotective effects of H(2) by analyzing ROS and cell damage. Also, C57BL/6J female mice received 15 Gy irradiation to the thorax. Treatment groups inhaled 3% H(2) gas and drank H(2)-enriched water. We evaluated acute and late-irradiation lung damage after H(2) treatment. H(2) reduced the amount of irradiation-induced ROS in A549 cells, as shown by electron spin resonance and fluorescent indicator signals. H(2) also reduced cell damage, measured as levels of oxidative stress and apoptotic markers, and improved cell viability. Within 1 wk after whole thorax irradiation, immunohistochemistry and immunoblotting showed that H(2) treatment reduced oxidative stress and apoptosis, measures of acute damage, in the lungs of mice. At 5 mo after irradiation, chest computed tomography, Ashcroft scores, and type III collagen deposition demonstrated that H(2) treatment reduced lung fibrosis (late damage). This study thus demonstrated that H(2) treatment is valuable for protection against irradiation lung damage with no known toxicity.
Ischemia-reperfusion injury is one of the leading causes of tissue damage and dysfunction, in particular, free tissue transfer, traumatically amputated extremity, and prolonged tourniquet application ...during extremity surgery. In this study, the authors investigated the therapeutic effects of hydrogen gas on skeletal muscle ischemia-reperfusion injury.
The authors compared the concentration of hydrogen in a muscle on intraperitoneal administration of hydrogen-rich saline and on inhalation of hydrogen gas. Animals were subjected to ischemia-reperfusion. Mice were treated with inhalation of hydrogen gas, and the hind gastrocnemius muscle was collected. Muscle morphology and inflammatory change were evaluated after ischemia-reperfusion. Moreover, a footprint test was performed to assess the functional effect of hydrogen.
Hydrogen concentration of tissue was significantly higher, and the elevated level was maintained longer by hydrogen gas inhalation than by intraperitoneal administration of hydrogen-rich saline. Infarct zone and area with loss of tissue structure and marked cellular infiltration were significantly decreased in groups treated by hydrogen gas inhalation during ischemia-reperfusion; however, these effects were not observed by posttreatment of hydrogen. One week after ischemia-reperfusion, mice that had been pretreated with hydrogen gas recovered faster and achieved smoother walking in appearance compared with mice in the other groups as assessed by the footprint test.
Inhalation of hydrogen gas attenuates muscle damage, inhibits inflammatory response, and enhances functional recovery. These findings suggest that the optimal route for hydrogen delivery is continuous inhalation of hydrogen gas, which could be a novel clinical mode of treatment in ischemia-reperfusion injury.
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