Oxygen

Cancer remains one of the leading causes of death despite advancements in research and treatment, with traditional therapies often causing significant side effects and resistance. Oxyhydrogen gas, a mixture of 66% molecular hydrogen (H₂) and 33% molecular oxygen (O₂) has shown exceptional promise as a novel therapeutic agent due to its ability to modulate oxidative stress, inflammation, and apoptosis. H₂, a key component of oxyhydrogen gas, neutralises reactive oxygen and nitrogen species, enhancing existing treatments and reducing harmful oxidative states in cancer cells. H₂ also lowers proinflammatory mediators including chemokines, cytokines, and interleukins, inhibiting cancer cell proliferation and boosting the effectiveness of conventional therapies. Additionally, hydrogen can induce apoptosis in cancer cells by modulating pathways such as MAPK and inhibiting the PI3K/Akt phosphorylation cascade. Preclinical and clinical evidence supports oxyhydrogen gas’s potential in treating various cancers. In lung cancer models, it inhibits cell proliferation, induces apoptosis, and enhances chemotherapy sensitivity. Similar results have been observed in breast cancer, where patients reported improved quality of life. In colorectal cancer, oxyhydrogen gas suppresses tumour growth, induces apoptosis, and improves intestinal microflora dysbiosis. The unique properties of oxyhydrogen gas make it a promising adjunctive or standalone cancer treatment. However, further research is needed to understand H₂s’ mechanisms, optimise treatment protocols, and evaluate long-term safety and efficacy in human patients. Full article

Oxidative stress, characterized by an imbalance between the production of reactive oxygen species and the body’s antioxidant defenses, plays an important role in the pathogenesis of various health conditions, including cancer and neurological disorders. For example, excessive ROS can lead to mutations, genomic instability, and uncontrolled cell proliferation in cancer. In neurological disorders, oxidative stress contributes to neuronal damage, inflammation, and the progression of diseases such as Alzheimer’s and Parkinson’s diseases. Adenosine, a nucleoside involved in energy transfer and signal transduction, is crucial to maintaining cellular homeostasis. Its role extends to modulating oxidative stress. Adenosine receptors are implicated in various physiological processes and in the pathophysiology of diseases. The interplay between oxidative stress and adenosine signaling is complex and critical. Adenosine can modulate oxidative stress responses, providing therapeutic potential for conditions where oxidative stress is a key player. Understanding this connection opens up avenues for novel therapeutic strategies targeting adenosine receptors to mitigate oxidative damage. Full article

This study explored the use of mandarin peels as an important source of health-promoting compounds by utilizing green methods (i.e., pulsed electric field and ultrasound-assisted extraction), along with conventional stirring. The impact of several extraction parameters, such as extraction duration, temperature, and solvent composition, on the recovery of bioactive compounds was evaluated through a response surface methodology. To identify the most effective conditions for all assays, a partial least-squares analysis was implemented. It was revealed that a combination of the above techniques was optimal at 80 °C for 30 min, with 75% v/v of ethanol in water as the extraction solvent. The concentration of bioactive compounds in the optimum extract had a total polyphenol content of 18.69 mg of gallic acid equivalents (GAE) per gram of dry weight (dw), and an ascorbic acid concentration of 18.25 mg/g dw. However, correlation analyses revealed a rather negative relationship between these bioactive compounds. The chromatographic analysis of optimum extracts supported this result by quantifying 20.53 mg/g dw of total individual polyphenols, with hesperidin being the dominant compound (13.98 mg/g dw). The antioxidant assays, including ferric-reducing antioxidant power and DPPH^• inhibition activity, were measured at 123.21 and 65.12 μmol of ascorbic acid equivalents (AAE) per gram of dw, respectively. This research enhances the valorization of mandarin peels as a renewable source of bioactive compounds, providing the opportunity to generate high-added-value products from food waste in the food and pharmaceutical sectors. Full article

This study focuses on post-harvest pest management in agriculture, in particular the transition to modified atmospheres as a sustainable alternative to conventional pesticide methods. Using Computational Fluid Dynamics (CFD) simulations, we analysed the dynamics of oxygen distribution within a pest control chamber. We tested four different configurations of nitrogen inlet and outlet positions to determine the most effective setup. The simulations used the twoLiquidMixingFoam solver in OpenFOAM to model gas mixing and diffusion. Our results show that the configuration with the nitrogen inlet at the top and the outlet at the bottom (Case D) was the most efficient. This configuration reached the target oxygen concentration of 1.5% in 4.4 h, significantly faster than the other configurations. These results highlight the importance of inlet and outlet positioning in improving the efficiency of oxygen reduction and ensuring a consistent low oxygen level throughout the chamber. Optimising the placement of nitrogen inlets and outlets has significant potential to improve the effectiveness of modified atmosphere treatments for pest control. Future research should consider additional environmental factors, different storage conditions and insect mortality models to further refine these methods. Full article

Lower limb muscle fatigue is the main reason for withdrawal from diving. Therefore, this study aimed to determine the local muscle oxygen saturation and hemoglobin concentration in the vastus lateralis muscle during different freediving disciplines. One freediver participated in this study, and his chronological age was 40 years, body mass 75.0 kg, body height 184.0 cm, and body fat 13.7%. The participant has been practicing freediving for 6 years. The variables in this study included anthropometric indices, heart rate, and muscle oxygen dynamics parameters (SmO₂ (oxygen muscle saturation) and tHb (total hemoglobin)). The variables were measured during five diving disciplines: static apnea, bifin, dynamic no fins (DNF), monofin, and sneaking. Measurements were performed during intensive training/competition during the diving season in August 2023. The results of this study showed that when oxygen starts to decrease during the dive, the tHb increases. Furthermore, the times at which maximal tHb and minimal SmO₂ were achieved are also shown. These parameters occurred at almost the same time across all disciplines: static (SmO₂, 142; tHb, 150 s), bifin (SmO₂, 153; tHb, 148 s), DNF (SmO₂, 162; tHb, 178 s), monofin (SmO₂, 96; tHb, 94 s), and sneaking (SmO₂, 212; tHb, 228 s). Also, differences in tHb and SmO₂ were present between diving disciplines. In particular, the highest increase in tHb was present in bifin (0.0028 AU/s), whereas monofin showed a decrease (−0.0009 AU/s). On the other hand, the highest desaturation was seen in bifin (−0.87%/s) and the lowest in sneaking (−0.29%/s) These findings emphasize the physiological characteristics of freedivers engaging in different freediving disciplines that influence muscles during the dive. Such responses could be observed through a concurrent hypoxia/hypercapnia and a transient reduction in the Fahraeus effect. Full article

Liquid organic hydrogen carriers (LOHCs) are aromatic molecules that are being considered for the safe storage and release of hydrogen. The thermodynamic properties of a range of aromatic ethers were investigated using various experimental and theoretical methods to assess their suitability as LOHC materials. The absolute vapour pressures were measured for benzyl phenyl ether, dibenzyl ether and 2-methoxynaphthalene using the transpiration method. The standard molar enthalpies and entropies of vaporisation/sublimation were derived from the temperature dependence of the vapour pressures. The combustion energies of benzyl phenyl ether and dibenzyl ether were measured using high-precision combustion calorimetry, and their standard molar enthalpies of formation were derived from these data. High-level quantum chemical calculations were used to calculate the standard molar enthalpies of formation in the gas phase for benzyl phenyl ether, dibenzyl ether and 2-methoxynaphthalene. The latter values agreed very well with the experimental results obtained in this work. The thermodynamic properties of the hydrogenation/dehydrogenation reactions in liquid phase in LOHC systems based on methoxy–benzene, diphenyl ether, benzyl phenyl ether, dibenzyl ether and 2-methoxynaphthalene were derived and compared with the data for similarly structured hydrogen carriers based on benzene, diphenylmethane, 1,2-diphenylethane, 1,3-diphenylpropane and naphthalene. The influence of the oxygen functionality on the thermodynamic properties of the hydrogenation/dehydrogenation reactions was evaluated. Full article

Rheumatoid arthritis (RA) is a well-known autoimmune inflammatory disease that affects the diarthrodial joints. Inflammation increases the production of reactive oxygen species (ROS), which may explain why RA is one of the diseases that induce oxidative stress. This study aimed to evaluate the potential differences in biochemical, hematological, and oxidative stress markers in the early stages of RA and after different treatment regimens. The study involved 111 patients, 28 men and 83 women aged 34 to 59 years, who were divided based on their c-reactive protein (CRP) levels into inactive RA patients (IRA) with CRP < 1.3 (n = 57, 22 men and 35 women) and active RA patients (ARA) with CRP ≥ 1.3 (n = 54, 6 men and 48 women). The study participants were divided into two groups, A and B, based on their treatment regimen. Group A, 90% of which were IRA patients, received methotrexate (MTX) monotherapy. Group B, which comprised 90% ARA patients, received a combination of leflunomide, a conventional disease-modifying antirheumatic drug (DMARD), and a biologic DMARD. The hematological, biochemical, oxidative stress, and RA-specific biomarkers were measured twice in groups A and B in the early stage of the disease, before and 3 months post-treatment, using conventional colorimetric, fluorometric, and immunological assays. According to the results of our study, glutathione peroxidase (GPx), ROS, calcium (Ca) and phosphorus (P) ions, vitamin C and D, and lipid profiles could serve as potential diagnostic markers in the early stages of the disease. Both treatment options were equally effective at improving the overall health of the patients. However, treatment resulted in a further increase in ROS levels and a decrease in antioxidant markers. Full article

Uterine fibroids are the most common tumors in females, affecting up to 70% of women worldwide, yet targeted therapeutic options are limited. Oxidative stress has recently surfaced as a key driver of fibroid pathogenesis and provides insights into hypoxia-induced cell transformation, extracellular matrix pathophysiology, hypoxic cell signaling cascades, and uterine biology. Hypoxia drives fibroid tumorigenesis through (1) promoting myometrial stem cell proliferation, (2) causing DNA damage propelling the transformation of stem cells to tumor-initiating cells, and (3) driving excess extracellular matrix (ECM) production. Common fibroid-associated DNA mutations include MED12 mutations, HMGA2 overexpression, and fumarate hydratase loss of function. Evidence suggests an interaction between hypoxia signaling and these mutations. Fibroid development and growth are promoted by hypoxia-triggered cell signaling via various pathways including HIF-1, TGFβ, and Wnt/β-catenin. Fibroid-associated hypoxia persists due to antioxidant imbalance, ECM accumulation, and growth beyond adequate vascular supply. Current clinically available fibroid treatments do not take advantage of hypoxia-targeting therapies. A growing number of pre-clinical and clinical studies identify ROS inhibitors, anti-HIF-1 agents, Wnt/β-catenin inhibition, and TGFβ cascade inhibitors as agents that may reduce fibroid development and growth through targeting hypoxia. Full article

This review explores the unique structural and functional characteristics of natural products featuring highly oxygenated cyclobutane rings, with a specific focus on oxetane and 1,2-dioxetane motifs. It presents the structures and biological activities of compounds containing these rings, highlighting their contribution to molecular stability and pharmacological potency. Through detailed case studies and recent research findings, it has been demonstrated that these oxygen-rich rings enhance the molecular diversity and biological efficacy of natural products, potentially offering new avenues for drug development. Notably, these compounds are predominantly synthesized by microorganisms and can also be found in extracts from fungi, plants, and certain marine invertebrates. Compounds with oxetane and 1,2-dioxetane rings are primarily noted for their strong antineoplastic properties, among other biological activities. In contrast, most 1,2-dioxetanes exhibit potent antiprotozoal effects. It is important to note that 1,2-dioxetanes often serve as intermediate products in oxidation reactions, characterized by their instability and propensity to decompose into new compounds. Full article

Halophyte plants and seaweed are described in the literature as rich sources of antioxidant compounds that can be used in the pharmaceutical and food industries. In this work, we studied the antioxidant composition of five species of halophytic plants (Suaeda vera Forssk, Halimione portulacoides L., Inula crithmoides L., Salicornia ramosissima (Hook.f.) J. Woods and Sarcocornia perennis (Mill.) A.J.Scott) and three seaweeds (Gracilaria gracilis (Stackhouse) Steentoft, L.Irvine and Farnham, Fucus spiralis L. and Ulva rigida C. Agardh) collected in Sado Estuary, Portugal. In the case of the plants, different parts of the plant were also assessed. Various extraction procedures were also performed to understand which methods were most suitable for extracting the various antioxidant compounds. Therefore, the aim of this study was to characterize the antioxidant compounds in halophytes and seaweed using various methods (ABTS, DPPH and FRAP), as well as the phenolic (TPC) and flavonoid (TFC) contents in the different extracts obtained. The amount of soluble protein in each extract was also determined. The results show that methanolic extracts generally have a higher antioxidant capacity, while the highest soluble protein content was observed in aqueous extracts. The seaweed Fucus Spiralis showed the highest antioxidant content, while in halophytic plants the highest antioxidant content was detected in the leaves. In general, this work confirms the potential of halophytes and seaweed as sources of antioxidant compounds for use in the food and pharmaceutical industries. Full article

Background: In otorhinolaryngology and head and neck surgery, oxygen is a therapeutic tool used for various pathologies. Oxidative stress is the imbalance between the production of free radicals (ROS) and the antioxidant capacity of the body, which can represent the pathogenesis of several pathologies or contribute to their worsening. This narrative review aims to analyze the benefits, indications, and side effects of hyperbaric oxygen therapy (HBOT) in different head and neck disorders. Methods: The search was carried out on multiple electronic databases such as PubMed and Google Scholar, and prospective, randomized, and reviewed studies were analyzed from January 1982 to February 2024. Results and Conclusions: The most common tools used to manage oxidative stress in the ear, nose, and throat (ENT) field are continuous positive airway pressure (CPAP) and HBOT. A common ENT pathology, while the latter can be used for osteoradionecrosis treatment in head and neck cancer patients, infections, malignant external otitis, head and neck reconstruction, facial cosmetic surgery, and among patients with sudden sensorineural hearing loss. From our analysis, it emerged that HBOT is a currently used effective therapy in various ENT pathologies’ treatment, alone or in association with other treatments; it can guarantee functional recovery and healing depending on the type of pathology for which it is used and on its severity. Full article

In this review, in addition to the potential cardiovascular applications of β-blockers and, more specifically, propranolol, we wanted to list the more recent applications in psychiatry as well as current knowledge on the impact of oxidative stress on propranolol hydrochloride and the oxidative stress that could be limited by the latter. In fact, a number of studies show that this molecule is modified by oxidative stress but is also able to limit it. Mention is also made to studies on the increasingly important problem of eliminating drug waste and its impact on the environment, particularly the marine environment. Given the increase in the consumption of medicines, more rigorous waste management is needed to avoid impacting biodiversity. Full article

The generation of energy within cells is a fundamental process enabling cell survival, and as such it represents a potential target in cancer therapy. In this article, we therefore review the relative contributions of glycolysis and oxidative phosphorylation/mitochondrial function to cancer cell energy generation, and we highlight their respective potential value as chemotherapeutic targets. This article is particularly focussed on the potential role of coenzyme Q10 in the prevention and treatment of cancer. Full article

The mitochondrial electron transport chain (mETC) contains molecular targets of volatile general anesthetics (VGAs), which places individuals with mETC mutations at risk for anesthetic complications, as exemplified by patients with Leigh syndrome (LS). The Drosophila melanogaster homozygous mutant for ND-23, which encodes a subunit of mETC Complex I, replicates numerous characteristics of LS, including neurodegeneration, shortened lifespan, behavioral anesthetic hypersensitivity, and toxicity. The anesthetic phenotype of toxicity (lethality) is also observed in flies homozygous for mutations in other Complex I subunits. By contrast, mutations conferring sensitivity have not yet been identified for subunits of Complexes II–V. Furthermore, anesthetic phenotypes are thought to be recessive; that is, risk is not conferred by heterozygous mutations. However, at older ages, exposure of heterozygous mutant ND-23 flies to the VGA isoflurane in 75% oxygen (hyperoxia) results in toxicity. It is also unknown whether combinations of heterozygous mutations in different subunits of the mETC can result in anesthetic toxicity. Here, we show that, following exposure to isoflurane in hyperoxia, flies carrying heterozygous mutations in two Complex I subunits, ND-23 and ND-SGDH (NADH dehydrogenase (ubiquinone) SGDH subunit), had a level of anesthetic toxicity that exceeded the added toxicities of the individual heterozygous mutations. In addition, we show that flies heterozygous for two different alleles of the Complex II gene SdhB were susceptible to isoflurane/hyperoxia-induced anesthetic toxicity. Finally, a mutation in the SdhC subunit of Complex II of Caenorhabditis elegans resulted in isoflurane-induced mortality, supporting the role of Complex II in anesthetic toxicity. These data expand the landscape of mutations in the mETC that increase sensitivity to anesthetic toxicity. Full article

The objective of this study was to determine the optimal conditions for the recovery of bioactive and antioxidant compounds in aqueous solutions of Cistus creticus leaves and then employ the optimal extract for the enrichment of yogurt samples. The optimal conditions were established by a response surface methodology and were determined to be a liquid-to-solid ratio of 48 mL/g at 76 °C for 41 min. The optimum extract yielded TPC 157.17 mg GAE/g dw and TFC 2.38 mg QE/g dw, while FRAP and DPPH values were 1258.52 and 933.67 μmol AAE/g dw, respectively. HPLC-DAD was utilized to identify and quantify specific polyphenols, like myricetin rhamnoside, in the extract. The optimal extract was then added to yogurt desserts during their preparation at three different concentrations to study how the physicochemical characteristics of the yogurt, as well as the antioxidant capacity added during enrichment, were affected. Statistical analysis of the results was carried out in order to obtain more valid data. It seems that the most suitable concentration for yogurt fortification was 0.1% w/v of the extract as, at this concentration, the yogurts exhibited higher antioxidant capacity, and their physicochemical characteristics were improved. Full article

On the thirty-fifth anniversary of the first description of O₂-sensitive K⁺ channels in the carotid body chemoreceptors O₂ sensing remains a salient issue in the literature. Whereas much has been learned about this subject, important questions such as the identity of the specific K⁺ channel subtype(s) responsible for O₂ sensing by chemoreceptors and the mechanism(s) by which their activities are altered by hypoxia have not yet been definitively answered. O₂ sensing is a fundamental biological process necessary for the acute and chronic responses to varying environmental O₂ levels which allow organisms to adapt to hypoxia. Whereas chronic responses depend on the modulation of hypoxia-inducible transcription factors which determine the expression of numerous genes encoding enzymes, transporters and growth factors, acute responses rely mainly on the dynamic modulation of ion channels by hypoxia, causing adaptive changes in cell excitability, contractility and secretory activity in specialized tissues. The most widely studied oxygen-sensitive ion channels are potassium channels, but oxygen sensing by members of both the calcium and sodium channel families has also been demonstrated. Given the explosion of information on this topic, in this review, we will focus on the mechanisms of physiological oxygen chemotransduction by PO₂-dependent K⁺ channels, with particular emphasis on their function in carotid body chemoreceptor cells (CBCC) and pulmonary artery smooth muscle cells (PASMC), highlighting areas of consensus and controversy within the field. We will first describe the most well-established concepts, those reproduced in multiple laboratories, and then discuss selected observations or questions that remain unresolved, and that limit our progress in this field. Full article

Produced by photosynthesis, oxygen (O₂) is a fundamentally important gas in biological systems, playing roles as a terminal electron receptor in respiration and in host defence through the creation of reactive oxygen species (ROS). Hydrogen (H₂) plays a role in metabolism for some organisms, such as at thermal vents and in the gut environment, but has a role in controlling growth and development, and in disease states, both in plants and animals. It has been suggested as a medical therapy and for enhancing agriculture. However, the exact mode of action of H₂ in biological systems is not fully established. Furthermore, there is an interrelationship between O₂ and H₂ in organisms. These gases may influence each other’s presence in solution, and may both interact with the same cellular components, such as haem prosthetic groups. It has also been suggested that H₂ may affect the structures of some proteins, such as globins, with possible effects on O₂ movement in organisms. Lastly, therapies may be based on supplying O₂ and H₂ together, such as with oxyhydrogen. Therefore, the relationship regarding how biological systems perceive and respond to both O₂ and H₂, and the interrelationship seen are worth considering, and will be discussed here. Full article

Background: Sepsis is a severe and life-threatening condition triggered by a dysregulated response to infection, leading to organ failure and, often, death. The syndrome is expensive to treat, with survivors frequently experiencing reduced quality of life and enduring various long-term disabilities. The increasing understanding of RNA, RNA biology, and therapeutic potential offers an unprecedented opportunity to develop innovative therapy. Objective: This study is a scoping review focusing on pre-clinical studies of microRNA (miRNA)-based therapies for sepsis. Methodology: A scoping review. The search strategy identified papers published in PubMed until 15 October 2023, using the keywords (microRNA) AND (sepsis) AND (animal model). Inclusion criteria included papers that used either gain- or loss-of-function approaches, excluding papers that did not focus on microRNAs as therapy targets, did not include animal models, did not show organ failure-specific assessments, and focused on microRNAs as biomarkers. The PRISMA-ScR guideline was used in this study. Results: A total of 199 articles were identified that featured the terms “microRNA/miRNA/miR”, “Sepsis”, and “animal model”. Of these, 51 articles (25.6%) employed miRNA-based therapeutic interventions in animal models of sepsis. Of these, 15 studies extended their inquiry to include or reference human clinical data. Key microRNAs of interest and their putative mechanisms of action in sepsis are highlighted. Conclusions: The body of work examined herein predominantly addresses various dimensions of sepsis-induced organ dysfunction, supporting the emerging role of miRNAs as potential therapeutic candidates. However, nearly 5% of papers on miR-based therapy have been retracted over the past 5 years, raising important concerns regarding the quality and complexity of the biology and models for assessing therapeutic potential. Full article