Hydrogen gas (H2) inhalation during hemorrhage stabilizes post-resuscitation hemodynamics, improving short-term survival in a rat hemorrhagic shock and resuscitation (HS/R) model. However, the underlying molecular mechanism of H2 in HS/R is unclear. Endothelial glycocalyx (EG) damage causes hemodynamic failure associated with HS/R. In this study, we tested the hypothesis that H2 alleviates oxidative stress by suppressing xanthine oxidoreductase (XOR) and/or preventing tumor necrosis factor-alfa (TNF-α)-mediated syndecan-1 shedding during EG damage.HS/R was induced in rats by reducing mean arterial pressure (MAP) to 35 mm Hg for 60 min followed by resuscitation. Rats inhaled oxygen or H2 + oxygen after achieving shock either in the presence or absence of an XOR inhibitor (XOR-I) for both the groups. In a second test, rats received oxygen alone or antitumor necrosis factor (TNF)-α monoclonal antibody with oxygen or H2. Two hours after resuscitation, XOR activity, purine metabolites, cytokines, syndecan-1 were measured and survival rates were assessed 6 h after resuscitation.H2 and XOR-I both suppressed MAP reduction and improved survival rates. H2 did not affect XOR activity and the therapeutic effects of XOR-I and H2 were additive. H2 suppressed plasma TNF-α and syndecan-1 expression; however, no additional H2 therapeutic effect was observed in the presence of anti-TNF-α monoclonal antibody.H2 inhalation after shock stabilized hemodynamics and improved survival rates in an HS/R model independent of XOR. The therapeutic action of H2 was partially mediated by inhibition of TNF-α-dependent syndecan-1 shedding.
Background: In a randomized trial, we demonstrated that hydrogen (H 2 ) inhalation improves outcomes after cardiac arrest (CA). All patients underwent target temperature management (TTM), but the selection of a target temperature between 32 and 36 °C varied per institutional protocol. Hypothesis: The combination of hypothermic TTM and H 2 improves neurological outcomes after CA. Aims: This study aimed to investigate the interaction of H 2 and hypothermic TTM on neurological outcomes after CA. Methods: This post-hoc analysis of a randomized controlled trial (HYBRID II Trial; jRCTs031180352) included comatose patients after cardiogenic out-of-hospital CA (OHCA). They received either 2% H 2 mixed oxygen (H 2 group) or oxygen alone (control group) for 18 hours under hypothermic TTM (<35°C) or normothermic TTM (35-36°C). A target temperature was reached quickly, maintained for 24 hours, and rewarmed over 48 hours. A good neurological outcome was defined as a Cerebral Performance Category (CPC) of 1 or 2 at 90 days. The neurological outcomes were compared between the H 2 and control groups under hypothermic or normothermic TTM. Results: The analysis included 72 patients with outcome data (39 and 33 patients in the H 2 and control group, respectively). Hypothermic TTM was implemented in 25 (64%) and 24 (73%) patients in the H 2 and control group, respectively (P=0.46). Under hypothermic TTM, 17 (68%) and 9 (38%) patients achieved CPC 1 or 2 in the H 2 and control group, respectively (relative risk 1.81 [95%CI: 1.05-3.66]). In contrast, under normothermic TTM, CPC of 1 or 2 was achieved in 5 (36%) and 4 (44%) patients (P>0.99) in the H 2 and control group, respectively. A multivariable logistic regression analysis indicated that the interaction between H 2 and hypothermic TTM was independently associated with CPC 1 or 2 at 90 days (adjusted odds ratio 3.71 [95%CI: 1.14-12.1]) after adjusting for confounding factors including age, sex, witness status, bystander CPR implementation, shockable rhythm, CA duration, and time from the return of spontaneous circulation to gas inhalation. Conclusions: H 2 in combination with hypothermic TTM improved neurologicaloutcomes after cardiogenic OHCA. However, the favorable effects of inhaled H 2 were not observed under normothermic TTM.
The benefits of inhaling hydrogen gas (H2) have been widely reported but its pharmacokinetics have not yet been sufficiently analyzed. We developed a new experimental system in pigs to closely evaluate the process by which H2 is absorbed in the lungs, enters the bloodstream, and is distributed, metabolized, and excreted. We inserted and secured catheters into the carotid artery (CA), portal vein (PV), and supra-hepatic inferior vena cava (IVC) to allow repeated blood sampling and performed bilateral thoracotomy to collapse the lungs. Then, using a hydrogen-absorbing alloy canister, we filled the lungs to the maximum inspiratory level with 100% H2. The pig was maintained for 30 seconds without resuming breathing, as if they were holding their breath. We collected blood from the three intravascular catheters after 0, 3, 10, 30, and 60 minutes and measured H2 concentration by gas chromatography. H2 concentration in the CA peaked immediately after breath holding; 3 min later, it dropped to 1/40 of the peak value. Peak H2 concentrations in the PV and IVC were 40% and 14% of that in the CA, respectively. However, H2 concentration decay in the PV and IVC (half-life: 310 s and 350 s, respectively) was slower than in the CA (half-life: 92 s). At 10 min, H2 concentration was significantly higher in venous blood than in arterial blood. At 60 min, H2 was detected in the portal blood at a concentration of 6.9–53 nL/mL higher than at steady state, and in the SVC 14–29 nL/mL higher than at steady state. In contrast, H2 concentration in the CA decreased to steady state levels. This is the first report showing that inhaled H2 is transported to the whole body by advection diffusion and metabolized dynamically.
The Efficacy of Inhaled Hydrogen on Neurologic Outcome Following Brain Ischemia During Post-Cardiac Arrest Care (HYBRID) II trial (jRCTs031180352) suggested that hydrogen inhalation may reduce post-cardiac arrest brain injury (PCABI). However, the combination of hypothermic target temperature management (TTM) and hydrogen inhalation on outcomes is unclear. The aim of this study was to investigate the combined effect of hydrogen inhalation and hypothermic TTM on outcomes after out-of-hospital cardiac arrest (OHCA).
Rationale: Despite the importance of inflammation in chronic obstructive pulmonary disease (COPD), the immune cell landscape in the lung tissue of patients with mild-moderate disease has not been well characterized at the single-cell and molecular level. Objectives: To define the immune cell landscape in lung tissue from patients with mild-moderate COPD at single-cell resolution. Methods: We performed single-cell transcriptomic, proteomic, and T-cell receptor repertoire analyses on lung tissue from patients with mild-moderate COPD (n = 5, Global Initiative for Chronic Obstructive Lung Disease I or II), emphysema without airflow obstruction (n = 5), end-stage COPD (n = 2), control (n = 6), or donors (n = 4). We validated in an independent patient cohort (N = 929) and integrated with the Hhip+/− murine model of COPD. Measurements and Main Results: Mild-moderate COPD lungs have increased abundance of two CD8+ T cell subpopulations: cytotoxic KLRG1+TIGIT+CX3CR1+ TEMRA (T effector memory CD45RA+) cells, and DNAM-1+CCR5+ T resident memory (TRM) cells. These CD8+ T cells interact with myeloid and alveolar type II cells via IFNG and have hyperexpanded T-cell receptor clonotypes. In an independent cohort, the CD8+KLRG1+ TEMRA cells are increased in mild-moderate COPD lung compared with control or end-stage COPD lung. Human CD8+KLRG1+ TEMRA cells are similar to CD8+ T cells driving inflammation in an aging-related murine model of COPD. Conclusions: CD8+ TEMRA cells are increased in mild-moderate COPD lung and may contribute to inflammation that precedes severe disease. Further study of these CD8+ T cells may have therapeutic implications for preventing severe COPD.
Objectives: Hemorrhagic shock is a life-threatening condition. In addition to conventional treatments such as hemostasis and fluid resuscitation, further investigations are warranted to develop more effective treatments. We investigated the effectiveness of hydrogen (H2) gas inhalation in a fixed-pressure model of hemorrhagic shock in rats. Methods: Hemorrhagic shock is induced by withdrawing blood from the left carotid artery until the mean arterial pressure (MAP) reaches 30~35 mmHg. Blood pressure is then maintained at this value either by further blood withdrawal or reinfusion of collected blood. Sixty minutes after shock induction, rats were resuscitated over a period of 15 minutes with a volume of saline, four times that of the shed blood. Inhalation of H2 gas (1.3% H2, 21% O2 and 77.7% N2, n=10) or control gas (21% O2 and 79% N2, n=10) was commenced at the beginning of the shock induction period, and continued for 2 hours after resuscitation. Results: (1) The H2 group shed more blood than controls to maintain hemorrhagic shock (2.76 ± 0.35 ml/100g vs 2.42 ± 0.39 ml/100g; p=0.058). (2) After resuscitation, the MAP in the H2 group reached a significantly higher level than in the control group [92.5 vs 71.0 mmHg (30 min), 103.0 vs 79.1 mmHg (60 min); 102.0 vs 70.4 mmHg (90min); 92.4 vs 63.1 mmHg (120min), p (3) The survival rate at 6 hours after resuscitation was significantly higher in the H2 group than in the control group (80% vs. 30%, p (4) H2 gas inhalation did not affect blood gases (pH, lactate, HCO3, base excess, PaO2, PaCO2, Hb, Hct) or blood chemistry (Na, K) before, or 6 hours after, fluid resuscitation. Conclusions: It is well accepted that survival time is prolonged by resuscitation with blood compared to saline. However, blood transfusions are not performed immediately at the site of an emergency. We have demonstrated that inhalation of H2 gas, commenced upon excessive bleeding, prolonged survival in rats resuscitated with saline alone after suffering a lethal hemorrhagic shock.
Background: Outcome prediction for patients with out-of-hospital cardiac arrest (OHCA) using prehospital information has been one of the major challenges in resuscitation medicine. Recently, machine learning techniques have been shown to be highly effective in predicting outcomes using clinical registries. In this study, we aimed to establish a prediction model for outcomes of OHCA of presumed cardiac cause using machine learning techniques. Methods: We analyzed data from the All-Japan Utstein Registry of the Fire and Disaster Management Agency between 2005 and 2016. Of 1,423,338 cases, data of OHCA patients aged ≥18 years with presumed cardiac etiology were retrieved and divided into two groups: training set, n = 584,748 (between 2005 and 2013) and test set, n = 223,314 (between 2014 and 2016). The endpoints were neurologic outcome at 1-month and survival at 1-month. Of 47 variables evaluated during the prehospital course, 19 variables (e.g.,sex, age, ECG waveform, and practice of bystander CPR) were used for outcome prediction. Performances of logistic regression, random forests, and deep neural network were examined in this study. Results: For prediction of neurologic outcomes (cerebral performance category 1 or 2) using the test set, the generated models showed area under the receiver operating characteristic curve (AUROC) values of 0.942 (95% confidence interval [CI] 0.941-0.943), 0.947 (95% CI 0.946-0.948), and 0.948 (95% CI 0.948-0.950) in logistic regression, random forest, and deep neural network, respectively. For survival prediction, the generated models showed AUROC values of 0.901 (95% CI 0.900-0.902), 0.913 (95% CI 0.912-0.914), and 0.912 (95% CI 0.911-0.913) in logistic regression, random forest, and deep neural network, respectively. Conclusions: Machine learning techniques using prehospital variables showed favorable prediction capability for 1-month neurologic outcome and survival in OHCA of presumed cardiac cause.
Background: Molecular hydrogen gas (H 2 ) is known to alleviate ischemia-reperfusion injury; however, the mechanism of action involved remains unknown. Metabolome analysis of tissue subjected to ischemia-reperfusion injury has revealed xanthine oxidoreductase (XOR) as a candidate target molecule for H 2. Purpose: The effects of H 2 and the XOR inhibitor (XORi) on resuscitation after hemorrhagic shock (HS) were examined. Methods: Male Sprague-Dawley rats were subjected to HS by the withdrawal of blood to maintain a mean arterial pressure (MBP) of 35 mmHg for 60 minutes (T0 to T60). They were then resuscitated with lactated Ringer’s solution with 3 times the shed blood volume over 30 minutes (T60 to T90). The animals were randomly assigned into 3 groups: H 2 inhalation (1.3% H 2 ) from T30 (n=6), XORi administration (Topiroxostat 10 mg/kg, orally administered at 60 minutes before induction of HS) (n=5), and control (CTL) (n=5). The rats were observed until 2 hours after fluid resuscitation (T210). Results: Compared to that in the control group, the lactate level at 60 minutes after introduction of HS was lower in the XORi group, while the MBP after 2 hours of fluid resuscitation was higher in the H 2 group. XOR activity in the plasma, liver, kidney, and lung tissue was suppressed in the XORi group, but not in the H 2 group. Increased permeability of the pulmonary vasculature associated with increased levels of plasma inflammatory cytokines and plasma Syndecan-1 (a marker of endothelial glycocalyx degradation) after 2 hours of fluid resuscitation was ameliorated only in the H 2 group. Conclusion: The mechanisms of action possibly differ between H 2 and XORi. XORi confers resistance to ischemia by suppressing anaerobic glycolysis during ischemia. On the other hand, H 2 stabilizes hemodynamics via suppression of inflammation and vascular hyperpermeability after resuscitation.
Renal dysfunction is associated with increased cardiovascular-related mortality, but its impact on outcome of out-of-hospital cardiac arrest (OHCA) remains unclear. We assessed whether post-OHCA outcome correlated with renal function early after OHCA.
Hydrogen gas inhalation (HI) improved survival and neurological outcomes in an animal model of post-cardiac arrest syndrome (PCAS). The feasibility and safety of HI for patients with PCAS was confirmed in a pilot study. The objective of this study is to evaluate the efficacy of HI for patients with PCAS. The efficacy of inhaled HYdrogen on neurological outcome following BRain Ischemia During post-cardiac arrest care (HYBRID II) trial is an investigator-initiated, randomized, double-blind, placebo-controlled trial designed to enroll 360 adult comatose (Glasgow Coma Scale score < 8) patients who will be resuscitated following an out-of-hospital cardiac arrest of a presumed cardiac cause. The patients will be randomized (1:1) to either the HI or control group. Patients in the HI group will inhale 2% hydrogen with 24% to 50% oxygen, and those in the control group will inhale 24% to 50% oxygen for 18 h after admission via mechanical ventilation. Multidisciplinary post-arrest care, including targeted temperature management (TTM) between 33 °C and 36 °C, will be provided in accordance with the latest guidelines. The primary outcome of interest is the 90-day neurological outcome, as evaluated using the Cerebral Performance Categories scale (CPC). The secondary outcomes of interest are the 90-day survival rate and other neurological outcomes. This study will provide 80% power to detect a 15% change in the proportion of patients with good neurological outcomes (CPCs of 1 and 2), from 50% to 65%, with an overall significance level of 0.05. The first multicenter randomized trial is underway to confirm the efficacy of HI on neurological outcomes in comatose out-of-hospital cardiac arrest survivors. Our study has the potential to address HI as an appealing and innovative therapeutic strategy for PCAS in combination with TTM. University Hospital Medical Information Network (UMIN), 000019820 . Registered on 17 November 2015.
