Review Papers in Oxygen

A special issue of Oxygen (ISSN 2673-9801).

Deadline for manuscript submissions: closed (15 October 2022) | Viewed by 57645

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Guest Editor
School of Applied Sciences, University of the West of England, Bristol, UK
Interests: redox signaling; reactive oxygen species; hydrogen sulfide; hydrogen gas; nitric oxide
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Special Issue Information

Dear Colleagues,

Oxygen is Earth’s most abundant element and, after hydrogen and helium, it is the third-most abundant element in the universe. Oxygen makes up almost half of the Earth’s crust in the form of oxides. Diatomic oxygen gas constitutes 21% of the Earth’s atmosphere. Most of the mass of living organisms is oxygen as a component of water, the major constituent of lifeforms. Oxygen is continuously replenished in Earth’s atmosphere by photosynthesis, which uses the energy of sunlight to produce oxygen from water and carbon dioxide. The name oxygen was coined in 1777 by Lavoisier, who first recognized oxygen as a chemical element and correctly characterized the role it plays in combustion. Common uses of oxygen include the production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and the support systems in aircraft, submarines, spaceflight and diving. One hundred million tonnes of oxygen are extracted from air for industrial uses annually. The smelting of iron ore into steel consumes 55% of commercially produced oxygen. Another produced oxygen is used by the chemical industry, creating ethylene oxide, ethylene glycol, many precursors of plastics and fabrics, in oxy-cracking processes, etc. Most of the remaining 20% of commercially produced oxygen is used in medical applications, water treatment and other applications, as reported above.

As a chemical engineer with a doctoral thesis is material science, César Augusto Correia de Sequeira has been working for many years in applied domains of electrochemistry in which oxygen has several applications, namely in energy conversion, storage and conservation (e.g., fuel cells, metal–air batteries), water electrolysis, recharging of metal–air cells, etc. Oxygen reduction also plays a role in the corrosion of metals, such as steel in the presence of air. In fact, due to its electronegativity, oxygen forms chemical bonds with almost all other elements to give corresponding oxides. The surfaces of most metals, such as aluminium and titanium, are oxidized in the presence of air and become coated with a thin film of oxide that passivates the metal and slows further corrosion. Passivation phenomena also occur at high temperatures, but the nonstoichiometric nature of the high temperature passive films, with characteristic ionic, electronic, or mixed conductivity, does not reduce corrosion as in low temperature situations.

 Therefore, we would like to invite you to contribute a review or opinion article for our Special Issue, Review Papers in Oxygen. The topic of articles can be anything which is in scope of the journal Oxygen, so may be drawn from areas of physics, chemistry or biology. This may include a review of novel reactions, or physical properties of oxygen-based molecules. Articles may also cover aspects of oxygen and oxygen-based compounds in normal physiology and disease, such as the reactive oxygen species and the role of antioxidants. However, reviews may cover novel uses of oxygen-based technologies, such as the use of oxygen therapies. We would particularly welcome manuscripts which offer opinions and look to the future, perhaps steering the direction of new endeavors involving oxygen.

Prof. Dr. John Hancock
Prof. Dr. César Augusto Correia de Sequeira
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Oxygen is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • reactive oxygen species
  • calvin cycle
  • oxygen electrocatalysis
  • oxygen storage
  • oxygen therapy
  • oxygen toxicity
  • oxygen consuming cathodes
  • oxygen oxidation reaction
  • oxygen reduction reaction
  • oxygen sensors
  • anodic films
  • electrocoagulation
  • electrooxidation

Published Papers (14 papers)

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32 pages, 2241 KiB  
Review
The Underexplored Landscape of Hypoxia-Inducible Factor 2 Alpha and Potential Roles in Tumor Macrophages: A Review
by Kayla J. Steinberger and Timothy D. Eubank
Oxygen 2023, 3(1), 45-76; https://doi.org/10.3390/oxygen3010005 - 31 Jan 2023
Cited by 6 | Viewed by 3175
Abstract
Low tissue oxygenation, termed hypoxia, is a characteristic of solid tumors with negative consequences. Tumor-associated macrophages (TAMs) accumulate in hypoxic tumor regions and correlate with worse outcomes in cancer patients across several tumor types. Thus, the molecular mechanism in which macrophages respond to [...] Read more.
Low tissue oxygenation, termed hypoxia, is a characteristic of solid tumors with negative consequences. Tumor-associated macrophages (TAMs) accumulate in hypoxic tumor regions and correlate with worse outcomes in cancer patients across several tumor types. Thus, the molecular mechanism in which macrophages respond to low oxygen tension has been increasingly investigated in the last decade. Hypoxia stabilizes a group of hypoxia-inducible transcription factors (HIFs) reported to drive transcriptional programs involved in cell survival, metabolism, and angiogenesis. Though both tumor macrophage HIF-1α and HIF-2α correlate with unfavorable tumor microenvironments, most research focuses on HIF-1α as the master regulator of hypoxia signaling, because HIF-1α expression was originally identified in several cancer types and correlates with worse outcome in cancer patients. The relative contribution of each HIFα subunit to cell phenotypes is poorly understood especially in TAMs. Once thought to have overlapping roles, recent investigation of macrophage HIF-2α has demonstrated a diverse function from HIF-1α. Little work has been published on the differential role of hypoxia-dependent macrophage HIF-2α when compared to HIF-1α in the context of tumor biology. This review highlights cellular HIF-2α functions and emphasizes the gap in research investigating oxygen-dependent functions of tumor macrophage HIF-2α. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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11 pages, 593 KiB  
Review
The Role of Oxidative Stress in Autism Spectrum Disorder: A Narrative Literature Review
by Valentina Membrino, Alice Di Paolo, Sonila Alia, Giulio Papiri and Arianna Vignini
Oxygen 2023, 3(1), 34-44; https://doi.org/10.3390/oxygen3010004 - 21 Jan 2023
Viewed by 4926
Abstract
Autism spectrum disorder (ASD) is a multifaceted neurodevelopmental disorder that comprises a complex aetiology, where a genetic component has been suggested, together with multiple environmental risk factors. Because of its increasing incidence in the paediatric population and the lack of successful curative therapies, [...] Read more.
Autism spectrum disorder (ASD) is a multifaceted neurodevelopmental disorder that comprises a complex aetiology, where a genetic component has been suggested, together with multiple environmental risk factors. Because of its increasing incidence in the paediatric population and the lack of successful curative therapies, ASD is one of the most puzzling disorders for medicine. In the last two decades and more, the relationship between oxidative stress (OS) and ASD has been recurrently documented. For this reason, the former hypothesis, according to which reactive oxygen and nitrogen species (ROS and RNS) play an important role in ASD, is now a certainty. Thus, in this review, we will discuss many aspects of the role of OS in ASD. In addition, we will describe, in the context of the most recent literature, the possibility that free radicals promote lipid peroxidation, as well as an increase in other OS biomarkers. Finally, we will outline the possibility of novel nutritional interventions aimed at counteracting ROS production in people with ASD. In fact, new strategies have investigated the possibility that ASD symptoms, as well behavioral anomalies, may be improved after interventions using antioxidants as supplements or included in foods. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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14 pages, 1783 KiB  
Review
Nanoparticles, a Double-Edged Sword with Oxidant as Well as Antioxidant Properties—A Review
by Antony V. Samrot, Sanjay Preeth Ram Singh, Rajalakshmi Deenadhayalan, Vinod Vincent Rajesh, Sathiyamoorthy Padmanaban and Kamalakannan Radhakrishnan
Oxygen 2022, 2(4), 591-604; https://doi.org/10.3390/oxygen2040039 - 15 Nov 2022
Cited by 20 | Viewed by 3549
Abstract
The usage of nanoparticles became inevitable in medicine and other fields when it was found that they could be administered to hosts to act as oxidants or antioxidants. These oxidative nanoparticles act as pro-oxidants and induce oxidative stress-mediated toxicity through the generation of [...] Read more.
The usage of nanoparticles became inevitable in medicine and other fields when it was found that they could be administered to hosts to act as oxidants or antioxidants. These oxidative nanoparticles act as pro-oxidants and induce oxidative stress-mediated toxicity through the generation of free radicals. Some nanoparticles can act as antioxidants to scavenge these free radicals and help in maintaining normal metabolism. The oxidant and antioxidant properties of nanoparticles rely on various factors including size, shape, chemical composition, etc. These properties also help them to be taken up by cells and lead to further interaction with cell organelles/biological macromolecules, leading to either the prevention of oxidative damage, the creation of mitochondrial dysfunction, damage to genetic material, or cytotoxic effects. It is important to know the properties that make these nanoparticles act as oxidants/antioxidants and the mechanisms behind them. In this review, the roles and mechanisms of nanoparticles as oxidants and antioxidants are explained. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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23 pages, 1659 KiB  
Review
Oxidative Stress as an Underlying Mechanism of Bacteria-Inflicted Damage to Male Gametes
by Eva Tvrdá, Filip Benko and Michal Ďuračka
Oxygen 2022, 2(4), 547-569; https://doi.org/10.3390/oxygen2040036 - 6 Nov 2022
Cited by 6 | Viewed by 4129
Abstract
Bacterial infestation of the male reproductive system with subsequent effects of bacteria on the structural integrity and functional activity of male gametes has become a significant factor in the etiology of male reproductive dysfunction. Bacteria may affect male fertility either by directly interacting [...] Read more.
Bacterial infestation of the male reproductive system with subsequent effects of bacteria on the structural integrity and functional activity of male gametes has become a significant factor in the etiology of male reproductive dysfunction. Bacteria may affect male fertility either by directly interacting with structures critical for sperm survival or indirectly by triggering a local immune response, leukocytospermia or reactive oxygen species (ROS) overproduction followed by oxidative stress development. This review aims to provide an overview of the currently available knowledge on bacteriospermia-associated sperm damage with a special emphasis on oxidative mechanisms underlying sperm deterioration caused by bacterial action. At the same time, we strive to summarize readily available alternatives to prevent or counteract alterations to spermatozoa caused by bacterial colonization of semen or by oxidative stress as an accompanying phenomenon of bacteriospermia. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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10 pages, 1458 KiB  
Review
Reactive Oxygen and Sulfur Species: Partners in Crime
by Neil W. Blackstone
Oxygen 2022, 2(4), 493-502; https://doi.org/10.3390/oxygen2040032 - 15 Oct 2022
Viewed by 1733
Abstract
The emergence of complexity requires cooperation, yet selection typically favors defectors that do not cooperate. Such evolutionary conflict can be alleviated by a variety of mechanisms, allowing complexity to emerge. Chemiosmosis is one such mechanism. In syntrophic relationships, the chemiosmotic partner benefits simply [...] Read more.
The emergence of complexity requires cooperation, yet selection typically favors defectors that do not cooperate. Such evolutionary conflict can be alleviated by a variety of mechanisms, allowing complexity to emerge. Chemiosmosis is one such mechanism. In syntrophic relationships, the chemiosmotic partner benefits simply from exporting products. Failure to do this can result in highly reduced electron carriers and detrimental amounts of reactive oxygen species. Nevertheless, the role of this mechanism in the history of life (e.g., the origin of eukaryotes from prokaryotes) seems questionable because of much lower atmospheric levels of oxygen and a largely anaerobic ocean. In this context, the role of sulfur should be considered. The last eukaryotic common ancestor (LECA) was a facultative aerobe. Under anaerobic conditions, LECA likely carried out various forms of anaerobic metabolism. For instance, malate dismutation, in which malate is both oxidized and reduced, allows re-oxidizing NADH. The terminal electron acceptor, fumarate, forms succinate when reduced. When oxygen is present, an excess of succinate can lead to reverse electron flow, forming high levels of reactive oxygen species. Under anaerobic conditions, reactive sulfur species may have formed. Eliminating end products may thus have had a selective advantage even under the low atmospheric oxygen levels of the Proterozoic eon. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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42 pages, 2351 KiB  
Review
RONS and Oxidative Stress: An Overview of Basic Concepts
by Ana Karina Aranda-Rivera, Alfredo Cruz-Gregorio, Yalith Lyzet Arancibia-Hernández, Estefani Yaquelin Hernández-Cruz and José Pedraza-Chaverri
Oxygen 2022, 2(4), 437-478; https://doi.org/10.3390/oxygen2040030 - 10 Oct 2022
Cited by 69 | Viewed by 10830
Abstract
Oxidative stress (OS) has greatly interested the research community in understanding damaging processes occurring in cells. OS is triggered by an imbalance between reactive oxygen species (ROS) production and their elimination by the antioxidant system; however, ROS function as second messengers under physiological [...] Read more.
Oxidative stress (OS) has greatly interested the research community in understanding damaging processes occurring in cells. OS is triggered by an imbalance between reactive oxygen species (ROS) production and their elimination by the antioxidant system; however, ROS function as second messengers under physiological conditions. ROS are produced from endogenous and exogenous sources. Endogenous sources involve mitochondria, nicotinamide adenine dinucleotide phosphate hydrogen (NADPH), oxidases (NOXs), endoplasmic reticulum (ER), xanthine oxidases (XO), endothelial nitric oxide synthase (eNOs), and others. In contrast, exogenous ROS might be generated through ultraviolet (UV) light, ionizing radiation (IR), contaminants, and heavy metals, among others. It can damage DNA, lipids, and proteins if OS is not controlled. To avoid oxidative damage, antioxidant systems are activated. In the present review, we focus on the basic concepts of OS, highlighting the production of reactive oxygen and nitrogen species (RONS) derived from internal and external sources and the last elimination. Moreover, we include the cellular antioxidant system regulation and their ability to decrease OS. External antioxidants are also proposed as alternatives to ameliorate OS. Finally, we review diseases involving OS and their mechanisms. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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28 pages, 1128 KiB  
Review
The Ambiguous Aspects of Oxygen
by Gaetana Napolitano, Gianluca Fasciolo and Paola Venditti
Oxygen 2022, 2(3), 382-409; https://doi.org/10.3390/oxygen2030027 - 14 Sep 2022
Cited by 13 | Viewed by 3466
Abstract
For most living beings, oxygen is an essential molecule for survival, being the basis of biological oxidations, which satisfy most of the energy needs of aerobic organisms. Oxygen can also behave as a toxic agent posing a threat to the existence of living [...] Read more.
For most living beings, oxygen is an essential molecule for survival, being the basis of biological oxidations, which satisfy most of the energy needs of aerobic organisms. Oxygen can also behave as a toxic agent posing a threat to the existence of living beings since it can give rise to reactive oxygen species (ROS) that can oxidise biological macromolecules, among which proteins and lipids are the preferred targets. Oxidative damage can induce cell, tissue, and organ dysfunction, which leads to severe body damage and even death. The survival of the aerobic organism depends on the development of an elaborate antioxidant defence system adapted to the normal level of atmospheric oxygen. The production of ROS in the aerobic organism can occur accidentally from exposure to pollutants or radiation, but occurs constantly during normal metabolic reactions. Cells have evolved using ROS to their advantage. Indeed, ROS are used as signalling molecules in numerous physiological processes, including muscle contraction, regulation of insulin release, and adaptation to environmental changes. Therefore, supplementation with antioxidants must be used wisely. A low level of ROS is essential for adaptation processes, so an excess of antioxidants can be harmful. Conversely, in conditions where ROS production increases, antioxidants can be useful to avoid cellular dysfunction. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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11 pages, 282 KiB  
Review
Home Oxygen Therapy (HOT) in Stable Chronic Obstructive Pulmonary Disease (COPD) and Interstitial Lung Disease (ILD): Similarities, Differences and Doubts
by Andrea S. Melani, Rosa Metella Refini, Sara Croce and Maddalena Messina
Oxygen 2022, 2(3), 371-381; https://doi.org/10.3390/oxygen2030026 - 13 Sep 2022
Viewed by 2038
Abstract
This narrative paper reviews the current knowledge of Home Oxygen Therapy (HOT) in stable Chronic Obstructive Pulmonary Disease (COPD) and Interstitial Lung Disease (ILD), two major causes of Long-Term Oxygen Therapy (LTOT) prescription. There is evidence that LTOT improves survival in COPD subjects [...] Read more.
This narrative paper reviews the current knowledge of Home Oxygen Therapy (HOT) in stable Chronic Obstructive Pulmonary Disease (COPD) and Interstitial Lung Disease (ILD), two major causes of Long-Term Oxygen Therapy (LTOT) prescription. There is evidence that LTOT improves survival in COPD subjects with chronic severe respiratory failure. HOT is also used to contrast exercise and sleeping hypoxemia and to improve Quality of Life (QoL) and symptoms. Ambulatory Oxygen Therapy (AOT) did not assure generalized improvements in symptoms and Quality of Life (QoL) of COPD subjects. There is short-term evidence in a real-life study that AOT may improve QoL in ILD subjects with Exercise Oxygen Desaturation (EOD) and exertional dyspnea. There are some differences between guidelines and practices, which translate into variations in characteristics and rates of ILD and COPD subjects admitted to LTOT and AOT. Indications on titration of oxygen flow and the best oxygen delivery device for optimal management of AOT in COPD and ILD subjects are often vague or lacking. More work is needed for optimizing and customizing HOT in COPD and ILD subjects. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
11 pages, 2671 KiB  
Review
Photosynthetic Production of Molecular Oxygen by Water Oxidation
by Lars Olof Björn
Oxygen 2022, 2(3), 337-347; https://doi.org/10.3390/oxygen2030024 - 26 Aug 2022
Viewed by 2525
Abstract
This review deals with the production of oxygen by photo-oxidation of water, which is a topic fitting a journal devoted to oxygen. Most of the present biosphere, including mankind, depends on oxygen. Elucidating the mechanism is of importance for solving the present energy [...] Read more.
This review deals with the production of oxygen by photo-oxidation of water, which is a topic fitting a journal devoted to oxygen. Most of the present biosphere, including mankind, depends on oxygen. Elucidating the mechanism is of importance for solving the present energy crisis. Photosynthesis evolved in bacteria, first in a form that did not produce oxygen. The oxygen-producing version arose with the advent of cyanobacteria about three billion years ago. The production of oxygen by photo-oxidation of water requires the co-operative action of four photons. These are harvested from daylight by chlorophyll and other pigments (e.g., phycobiliproteins) and are channeled to photosystem II and photosystem I. The oxygen-evolving complex resides in photosystem II, surrounded by protein subunits, and contains one ion of calcium, four ions of manganese, and a number of oxygen atoms. For each quantum of energy it receives from absorbed light, it proceeds one step through a cycle of states known as the Kok–Joliot cycle. For each turn of the cycle, one molecule of oxygen (O2) is produced. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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23 pages, 1415 KiB  
Review
Roles of Reactive Oxygen Species in Vascular Complications of Diabetes: Therapeutic Properties of Medicinal Plants and Food
by Yi Tan, Meng Sam Cheong and Wai San Cheang
Oxygen 2022, 2(3), 246-268; https://doi.org/10.3390/oxygen2030018 - 2 Jul 2022
Cited by 15 | Viewed by 5909
Abstract
The rising prevalence of chronic metabolic disorders, such as obesity and type 2 diabetes, most notably associated with cardiovascular diseases, has emerged as a major global health concern. Reactive oxygen species (ROS) play physiological functions by maintaining normal cellular redox signaling. By contrast, [...] Read more.
The rising prevalence of chronic metabolic disorders, such as obesity and type 2 diabetes, most notably associated with cardiovascular diseases, has emerged as a major global health concern. Reactive oxygen species (ROS) play physiological functions by maintaining normal cellular redox signaling. By contrast, a disturbed balance occurring between ROS production and detoxification of reactive intermediates results in excessive oxidative stress. Oxidative stress is a critical mediator of endothelial dysfunction in obesity and diabetes. Under a hyperglycemic condition, the antioxidant enzymes are downregulated, resulting in an increased generation of ROS. Increases in ROS lead to impairment of endothelium-dependent vasodilatations by reducing NO bioavailability. Chronic treatments with antioxidants were reported to prevent the development of endothelial dysfunction in diabetic patients and animals; however, the beneficial effects of antioxidant treatment in combating vascular complications in diabetes remain controversial as antioxidants do not always reverse endothelial dysfunction in clinical settings. In this review, we summarize the latest progress in research focused on the role of ROS in vascular complications of diabetes and the antioxidant properties of bioactive compounds from medicinal plants and food in animal experiments and clinical studies to provide insights for the development of therapeutic strategies. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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13 pages, 705 KiB  
Review
Biological Relevance of Free Radicals in the Process of Physiological Capacitation and Cryocapacitation
by Filip Benko, Michal Ďuračka, Štefan Baňas, Norbert Lukáč and Eva Tvrdá
Oxygen 2022, 2(2), 164-176; https://doi.org/10.3390/oxygen2020014 - 27 May 2022
Cited by 7 | Viewed by 4275
Abstract
Before fertilization, spermatozoa must undergo a process called capacitation in order to fulfill their fertilization potential. This includes a series of structural, biochemical, and functional changes before a subsequent acrosome reaction and fusion with the oocyte. However, low temperatures during cryopreservation may induce [...] Read more.
Before fertilization, spermatozoa must undergo a process called capacitation in order to fulfill their fertilization potential. This includes a series of structural, biochemical, and functional changes before a subsequent acrosome reaction and fusion with the oocyte. However, low temperatures during cryopreservation may induce a premature activation of capacitation-like changes, also known as cryocapacitation, immediately after thawing, which may lead to a decreased viability, motility, and fertilization ability of cryopreserved spermatozoa. Furthermore, cryopreservation is responsible for the overgeneration of reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, and hydroxyl radicals, which may result in the development of oxidative stress, cell membrane damage, and lipid peroxidation. Despite that, both capacitation and cryocapacitation are considered to be oxidative events; however, potential beneficial or detrimental effects of ROS depend on a wide array of circumstances. This review summarizes the available information on the role of free radicals in the process of capacitation and cryocapacitation of spermatozoa. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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22 pages, 1523 KiB  
Review
Biological and Pharmacological Properties of Carbon Monoxide: A General Overview
by Anna Bilska-Wilkosz, Magdalena Górny and Małgorzata Iciek
Oxygen 2022, 2(2), 130-151; https://doi.org/10.3390/oxygen2020012 - 24 May 2022
Cited by 5 | Viewed by 3980
Abstract
Carbon monoxide (CO) is one of the most common causes of inhalation poisoning worldwide. However, it is also well known that CO is produced endogenously in the heme degradation reaction catalyzed by heme oxygenase (HO) enzymes. HO catalyzes the degradation of heme to [...] Read more.
Carbon monoxide (CO) is one of the most common causes of inhalation poisoning worldwide. However, it is also well known that CO is produced endogenously in the heme degradation reaction catalyzed by heme oxygenase (HO) enzymes. HO catalyzes the degradation of heme to equimolar quantities of CO, iron ions (Fe2+), and biliverdin. Three oxygen molecules (O2) and the electrons provided by NADPH-dependent cytochrome P450 reductase are used in the reaction. HO enzymes comprise three distinct isozymes: the inducible form, heme oxygenase-1 (HO-1); the constitutively expressed isozyme, heme oxygenase-2 (HO-2); and heme oxygenase-3 (HO-3), which is ubiquitously expressed but possesses low catalytic activity. According to some authors, HO-3 is rather a pseudogene originating from the HO-2 transcript, and it has only been identified in rats. Therefore, cellular HO activity is provided by two major isoforms—the inducible HO-1 and the constitutively expressed HO-2. For many years, endogenously generated CO was treated as a by-product of metabolism without any serious physiological or biochemical significance, while exogenous CO was considered only as an extremely toxic gas with lethal effects. Research in recent years has proven that endogenous and exogenous CO (which may be surprising, given public perceptions) acts not only as an agent that affects many intracellular pathways, but also as a therapeutic molecule. Hence, the modulation of the HO/CO system may be one option for a potential therapeutic strategy. Another option is the administration of CO by exogenous inhalation. As alternatives to gas administration, compounds known as CO-releasing molecules (CORMs) can be administered, since they can safely release CO in the body. The aim of this article is to provide a brief overview of the physiological and biochemical properties of CO and its therapeutic potential. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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5 pages, 213 KiB  
Review
Oxygenation of Newborns
by Ola Didrik Saugstad and Jannicke Hanne Andresen
Oxygen 2022, 2(2), 125-129; https://doi.org/10.3390/oxygen2020011 - 23 May 2022
Viewed by 2335
Abstract
The last 20–30 years, the oxygen exposure of newborn infants has been substantially reduced. This is mainly due to a dramatic reduction in the use of oxygen in the delivery room in newborn infants in need of positive pressure ventilation (PPV) and the [...] Read more.
The last 20–30 years, the oxygen exposure of newborn infants has been substantially reduced. This is mainly due to a dramatic reduction in the use of oxygen in the delivery room in newborn infants in need of positive pressure ventilation (PPV) and the better control of oxygen saturation with clearly defined targets in immature infants in need of supplemental oxygen during treatment in neonatal intensive care units. Term and near-term infants in need of IPPV in the delivery room should start with a FiO2 of 0.21. Between 28 and 31 weeks of gestation, an initial FiO2 of 0.21–0.30 is generally recommended. For immature infants, a higher FiO2 than 0.3 may be needed, although the optimal initial level is not defined. For all groups, it is recommended to adjust the FiO2 according to oxygen saturation (SpO2) and heart rate response. For immature infants, the combination of prolonged bradycardia and an SpO2 not reaching 80% within 5 min of life is associated with a substantially increased risk of death. For immature infants beyond the delivery room, an SpO2 target between 91 and 95% is recommended. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)

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10 pages, 798 KiB  
Perspective
Roles of Reactive Oxygen Species and Autophagy in the Pathogenesis of Cisplatin-Induced Acute Kidney Injury
by Sayuri Yoshikawa, Kurumi Taniguchi, Haruka Sawamura, Yuka Ikeda, Ai Tsuji and Satoru Matsuda
Oxygen 2022, 2(3), 317-326; https://doi.org/10.3390/oxygen2030022 - 5 Aug 2022
Cited by 3 | Viewed by 2414
Abstract
Cisplatin-induced acute kidney injury (AKI) is the main factor restraining the clinical application of cisplatin. The AKI is associated with high mortality and morbidity, but no effective pharmacological treatment is available at present. As increased levels of reactive oxygen species (ROS) may promote [...] Read more.
Cisplatin-induced acute kidney injury (AKI) is the main factor restraining the clinical application of cisplatin. The AKI is associated with high mortality and morbidity, but no effective pharmacological treatment is available at present. As increased levels of reactive oxygen species (ROS) may promote the progression of the injury, the elimination of ROS has been considered as an effective method to prevent the cisplatin-induced AKI. In addition, it has been revealed that an inducer of autophagy could protect kidney cells in the autophagy dependent manner. Induction of autophagy could also modulate the production of ROS in cases of renal injury. Therefore, kidney-targeted antioxidants and/or autophagy are urgently required for the better treatment of AKI. Accumulating evidence has indicated the important roles of gut microbiota in the pathogenesis of AKI. In addition, there is a scientific basis for considering future clinical applications of probiotics and/or prebiotics to treat cisplatin-induced AKI. Thus, gut microbiota might be a promising therapeutic target via the alteration of autophagy for the cancer therapy-induced nephrotoxicity. Full article
(This article belongs to the Special Issue Review Papers in Oxygen)
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