The preventive and therapeutic effects of molecular hydrogen in ocular diseases and injuries where oxidative stress is involved

The Impact of Hydrogen Inhalation Therapy on Blood Reactive Oxygen Species Levels: A Randomized Controlled Study

Reactive Oxygen Species (ROS) play a key role in physiological processes. However, the imbalance between ROS and antioxidants in favor of the former causes oxidative stress linked to numerous pathologies. Due to its unique attributes, including distinguished permeability and selective antioxidant capability, molecular hydrogen (H2) has become an essential therapeutic agent. Hydrogen Inhalation Therapy (HIT) has come to light as a promising strategy to counteract oxidative stress. In this randomized controlled study, we aimed to evaluate the effectiveness of HIT in reducing blood ROS levels. 37 participants with elevated ROS levels (d-ROMs value > 350 U.CARR) were enrolled in the study. Participants were divided into test and control groups. The test group participants received HIT, and then their blood ROS levels were measured immediately post-treatment and after 24 hours. Their results were compared to those of the control group participants who did not undergo HIT. The test group demonstrated a significant reduction in blood ROS levels after the treatment. These findings suggested the efficacy of HIT in reducing oxidative stress.

Novel Role of Molecular Hydrogen: The End of Ophthalmic Diseases?

Molecular hydrogen (H2) is a colorless, odorless, and tasteless gas which displays non-toxic features at high concentrations. H2 can alleviate oxidative damage, reduce inflammatory reactions and inhibit apoptosis cascades, thereby inducing protective and repairing effects on cells. H2 can be transported into the body in the form of H2 gas, hydrogen-rich water (HRW), hydrogen-rich saline (HRS) or H2 produced by intestinal bacteria. Accumulating evidence suggest that H2 is protective against multiple ophthalmic diseases, including cataracts, dry eye disease, diabetic retinopathy (DR) and other fields. In particular, H2 has been tested in the treatment of dry eye disease and corneal endothelial injury in clinical practice. This medical gas has brought hope to patients suffering from blindness. Although H2 has demonstrated promising therapeutic potentials and broad application prospects, further large-scale studies involving more patients are still needed to determine its optimal application mode and dosage. In this paper, we have reviewed the basic characteristics of H2, and its therapeutic effects in ophthalmic diseases. We also focus on the latest progress in the administration approaches and mechanisms underlying these benefits.

Mechanisms Underlying the Biological Effects of Molecular Hydrogen

Aberrant redox-sensitive reactions and accumulation of oxidative damage can impair body functions and contribute to the development of various pathologies and aging. Although antioxidant substances have long been recognized as a measure of alleviating oxidative stress and restoring redox balance, the arsenal of effective means of preventing the development of various disorders, is still limited. There is an emerging field that utilizes molecular hydrogen (H₂) as a scavenger of free radicals and reactive oxygen species (ROS). Among the remarkable characteristics of H₂ is its ability to counteract the harmful effects of hydroxyl radical and peroxynitrite without affecting the activity of functionally important ROS, such as hydrogen peroxide and nitric oxide. The beneficial effects of H₂ have been documented in numerous clinical studies and studies on animal models and cell cultures. However, the established scavenging activity of H₂ can only partially explain its beneficial effects because the effects are achieved at very low concentrations of H₂. Given the rate of H₂ diffusion, such low concentrations may not be sufficient to scavenge continuously generated ROS. H₂ can also act as a signaling molecule and induce defense responses. However, the exact targets and mechanism(s) by which H₂ exerts these effects are unknown. Here, we analyzed both positive and negative effects of the endogenous H₂, identified the redox-sensitive components of the pathways affected by molecular hydrogen, and also discussed the potential role of molecular hydrogen in regulating cellular redox.

Hydrogen gas inhalation alleviates myocardial ischemia-reperfusion injury by the inhibition of oxidative stress and NLRP3-mediated pyroptosis in rats

AIMS

Reperfusion therapy is the most common and effective treatment against ischemic heart disease (IHD), but the process inflicts massive ischemia/reperfusion (I/R) injury for which no treatment exists. Notably, reperfusion after ischemia causes ischemia/reperfusion injury (IR injury) and the "no-reflow" phenomenon seriously affecting the therapeutic effects in clinical practice. The principle purpose of this study is to validate the effect of hydrogen gas on IHD and further explore the mechanism of hydrogen gas in alleviating myocardial I/R injury and no-reflow phenomenon.

MATERIALS AND METHODS

The rat model of myocardial ischemia-reperfusion was well established. Myocardial infarct size was evaluated by TTC & Evans blue staining. The no-reflow area and the cardiac function were assessed by thioflavin-S staining and echocardiography respectively. Microstructure and mitochondria of myocardial tissue were assessed by transmission electron microscope. Western blot and immunohistochemistry were used to evaluate the expression of NLRP3 mediated pyroptosis related proteins. The 8-OHdG, MDA and serum total ROS were used to evaluate the degree of oxidative stress.

KEY FINDINGS

The myocardial infarct size, no-reflow area, cardiac function, microstructure and mitochondrial morphology of I/R model rats were significantly improved after hydrogen inhalation. In addition, the expression of 8-OHdG, MDA, ROS and NLRP3 mediated pyroptosis related proteins were significantly decreased.

SIGNIFICANCE

We found that oxidative stress and NLRP3 mediated pyroptosis are the important mechanisms for hydrogen to alleviate myocardial I/R injury, and we also confirmed that hydrogen can significantly improve no reflow phenomenon caused by ischemia-reperfusion.

A three-channel fluorescent probe to image mitochondrial stress

Dual-recognition probes based on one reacting site inevitably encounter competition problems. Here, NPClA, a two-photon fluorescent probe based on a dual-site response for SO2/HOCl, was developed and applied in imaging mitochondrial stress.

Water-Splitting Based and Related Therapeutic Effects: Evolving Concepts, Progress, and Perspectives

Water-splitting has been extensively studied especially for energy applications. It is often not paid with enough attention for biomedical applications. In fact, several innovative breakthroughs have been achieved in the past few years by employing water-splitting for treating cancer and other diseases. Interestingly, among these important works, only two reports have mentioned the term "water-splitting." For this reason, the importance of water-splitting for biomedical applications is significantly underestimated. This progress work is written with the aims to explain and summarize how the principle of water-splitting is employed to achieve therapeutic results not offered by conventional approaches. It is expected that this progress report will not only explain the importance of water-splitting to scientists in the biomedical fields, it should also draw attention from scientists working on energy applications of water-splitting.

Phototherapy-based combination strategies for bacterial infection treatment

The development of nanomedicine is expected to provide an innovative direction for addressing challenges associated with multidrug-resistant (MDR) bacteria. In the past decades, although nanotechnology-based phototherapy has been developed for antimicrobial treatment since it rarely causes bacterial resistance, the clinical application of single-mode phototherapy has been limited due to poor tissue penetration of light sources. Therefore, combinatorial strategies are being developed. In this review, we first summarized the current phototherapy agents, which were classified into two functional categories: organic phototherapy agents (e.g., small molecule photosensitizers, small molecule photosensitizer-loaded nanoparticles and polymer-based photosensitizers) and inorganic phototherapy agents (e.g., carbo-based nanomaterials, metal-based nanomaterials, composite nanomaterials and quantum dots). Then the development of emerging phototherapy-based combinatorial strategies, including combination with chemotherapy, combination with chemodynamic therapy, combination with gas therapy, and multiple combination therapy, are presented and future directions are further discussed. The purpose of this review is to highlight the potential of phototherapy to deal with bacterial infections and to propose that the combination therapy strategy is an effective way to solve the challenges of single-mode phototherapy.

Intake of Molecular Hydrogen in Drinking Water Increases Membrane Transporters, p-Glycoprotein, and Multidrug Resistance-Associated Protein 2 without Affecting Xenobiotic-Metabolizing Enzymes in Rat Liver

Molecular hydrogen (H2) has been shown to have antioxidant and anti-inflammatory activities that may reduce the development and progression of many diseases. In this study, hydrogen-rich water (HRW) was obtained by reacting hybrid magnesium-carbon hydrogen storage materials with water. Then, the effects of intake of HRW on the activities of xenobiotic-metabolizing enzymes, membrane transporters, and oxidative stress in rats were investigated. Rats were given HRW ad libitum for four weeks. The results showed that intake of HRW had no significant effect on the activities of various cytochrome P450 (CYP) enzymes (CYP1A1, 1A2, 2B, 2C, 2D, 2E1, 3A, and 4A), glutathione-S-transferase, and Uridine 5'-diphospho (UDP)-glucuronosyltransferase. Except for a mild lower plasma glucose concentration, intake of HRW had no effect on other plasma biochemical parameters in rats. p-Glycoprotein and multidrug resistance-associated protein (Mrp) 2 protein expressions in liver were elevated after intake of HRW. However, HRW had no significant effects on glutathione, glutathione peroxidase, or lipid peroxidation in liver. The results from this study suggest that consumption of HRW may not affect xenobiotic metabolism or oxidative stress in liver. However, intake of HRW may increase the efflux of xenobiotics or toxic substances from the liver into bile by enhancing p-glycoprotein and Mrp2 protein expressions.