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Winner G J, Jain S, Gupta D. Unveiling Novel Molecules and Therapeutic Targets in Hypertension - A Narrative Review. Eur J Pharmacol 2024:177053. [PMID: 39393666 DOI: 10.1016/j.ejphar.2024.177053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 09/18/2024] [Accepted: 10/07/2024] [Indexed: 10/13/2024]
Abstract
Hypertension is a prevalent non-communicable disease with serious cardiovascular complications, including heart failure, myocardial infarction, and stroke, often resulting from uncontrolled hypertension. While current treatments primarily target the renin-angiotensin-aldosterone pathway, the therapeutic response remains modest in many patients, with some developing resistant hypertension. Newer therapeutic approaches aim to address hypertension from various aspects beyond conventional drugs, including targeting central nervous system pathways, inflammatory pathways, vascular smooth muscle function, and baroreceptors. Despite these advancements, each therapy faces unique clinical and mechanistic challenges that influence its clinical translatability and long-term viability. This review explores the mechanisms of novel molecules in preclinical and clinical development, highlights potential therapeutic targets, and discusses the challenges and ethical considerations related to hypertension therapeutics and their development.
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Mathis BJ, Kato H, Matsuishi Y, Hiramatsu Y. Endogenous and exogenous protection from surgically induced reactive oxygen and nitrogen species. Surg Today 2024; 54:1-13. [PMID: 36348164 DOI: 10.1007/s00595-022-02612-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 10/11/2022] [Indexed: 11/09/2022]
Abstract
Surgical intervention creates reactive oxygen species through diverse molecular mechanisms, including direct stimulation of immune-mediated inflammation necessary for wound healing. However, dysregulation of redox homeostasis in surgical patients overwhelms the endogenous defense system, slowing the healing process and damaging organs. We broadly surveyed reactive oxygen species that result from surgical interventions and the endogenous and/or exogenous antioxidants that control them. This study assimilates current reports on surgical sources of reactive oxygen and nitrogen species along with literature reports on the effects of endogenous and exogenous antioxidants in human, animal, and clinical settings. Although exogenous antioxidants are generally beneficial, endogenous antioxidant systems account for over 80% of total activity, varying based on patient age, sex, and health or co-morbidity status, especially in smokers, the diabetic, and the obese. Supplementation of exogenous compounds for support in surgical patients is thus theoretically beneficial, but a lack of persuasive clinical evidence has left this potential patient support strategy without clear guidelines. A more thorough understanding of the mechanisms of exogenous antioxidants in patients with compromised health statuses and pharmacokinetic profiling may increase the utility of such support in both the operating and recovery rooms.
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Affiliation(s)
- Bryan J Mathis
- International Medical Center, University of Tsukuba Affiliated Hospital, 2-1-1 Amakubo, Tsukuba, 305-8576, Ibaraki, Japan.
| | - Hideyuki Kato
- Department of Cardiovascular Surgery, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Yujiro Matsuishi
- Department of Neuroscience Nursing, St. Luke's International University, Tokyo, Japan
| | - Yuji Hiramatsu
- Department of Cardiovascular Surgery, University of Tsukuba, Tsukuba, Ibaraki, Japan
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3
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Cui X, Mi T, Zhang H, Gao P, Xiao X, Lee J, Guelakis M, Gu X. Glutathione amino acid precursors protect skin from UVB-induced damage and improve skin tone. J Eur Acad Dermatol Venereol 2024; 38 Suppl 3:12-20. [PMID: 38189671 DOI: 10.1111/jdv.19718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 11/21/2023] [Indexed: 01/09/2024]
Abstract
BACKGROUND UV radiation exposure causes skin irritation, erythema, darkening and barrier disruption by inducing oxidative stress and inflammation. Glutathione, a master antioxidant, plays an important role in the antioxidant defence network of the skin. OBJECTIVE This study aimed to assess the in vitro protective effects of the glutathione amino acid precursors blend (GAP) on transcriptomic and phenotypic endpoints against UVB-induced challenges. METHODS Normal human epidermal melanocytes (NHEMs) were exposed to GAP, ascorbic acid (AA) and its derivatives. Viability was assessed using the CCK8 method. Melakutis®, a pigmented living skin equivalent (pLSE) model, underwent repeated 50 mJ/cm2 UVB irradiation with or without GAP treatment. Images of the model were captured with consistent camera parameters, and the model's light intensity was measured using a spectrophotometer. Melanin content was determined by measuring absorbance at 405 nm. Confirmation of melanin deposition and distribution was achieved through Fontana-Masson staining. Transcriptomic analysis was conducted using RNA sequencing (RNA-Seq), and a machine learning approach was employed for transcriptomic aging clock analysis. RESULTS In NHEMs, all tested compounds exhibited over 85% viability compared to the vehicle control, indicating no heightened risk of cytotoxicity. Notably, GAP demonstrated greater efficacy in inhibiting melanin production than AA derivatives at equivalent concentrations. In pLSE models, GAP notably enhanced model lightness, and reduced melanin content and deposition following the UVB challenge, whereas AA showed minimal impact. GAP effectively counteracted UVB-induced alterations in gene expression linked to pigmentation, inflammation and aging. Moreover, recurrent UVB exposure substantially elevated the biological age of pLSE models, a phenomenon mitigated by GAP treatment. CONCLUSIONS In NHEMs, GAP exhibited enhanced effectiveness in inhibiting melanin production at identical tested doses in comparison to AA derivatives. Noteworthy protective effects of GAP against UVB irradiation were observed in the pLSE models, as evidenced by skin pigmentation measurements and transcriptomic changes.
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Affiliation(s)
- Xiao Cui
- Unilever R&D Shanghai, Shanghai, China
| | | | | | - Ping Gao
- Unilever R&D Shanghai, Shanghai, China
| | - Xue Xiao
- Unilever R&D Shanghai, Shanghai, China
| | - Jianming Lee
- Unilever R&D Trumbull, Trumbull, Connecticut, USA
| | | | - Xuelan Gu
- Unilever R&D Shanghai, Shanghai, China
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Lykkesfeldt J, Carr AC. Vitamin C - a scoping review for Nordic Nutrition Recommendations 2023. Food Nutr Res 2023; 67:10300. [PMID: 38187788 PMCID: PMC10770653 DOI: 10.29219/fnr.v67.10300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/29/2022] [Accepted: 10/16/2023] [Indexed: 01/09/2024] Open
Abstract
Vitamin C has multiple metabolic functions in the body, but the available information on the exact relationship between these functions and the intake necessary to maintain them is very limited. However, most attempts to objectively measure adequacy of vitamin C status, including, for example, replacement of metabolic turnover, chronic disease prevention, urinary excretion, and saturation of immune cells and body compartment, currently point toward 50 µmol/L as a reasonable target plasma concentration. As a strong correlation between body weight and vitamin C status exists, recommended intakes (RIs) for other age groups may be extrapolated from the adult RI based on weight. However, as body weights above 70 kg are becoming increasingly common - also in the Nordic region - an RI of 140 mg/day for individuals weighing 100 kg or more should be considered to compensate for the larger volume of distribution. Finally, smoking continues to be a common contributor to poor vitamin C status; therefore, it is proposed that people who smoke increase their daily vitamin C intake by 40 mg/day to compensate for the increased metabolic turnover induced by smoking.
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Affiliation(s)
- Jens Lykkesfeldt
- Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anitra C. Carr
- Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand
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5
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Hondal RJ. Selenium vitaminology: The connection between selenium, vitamin C, vitamin E, and ergothioneine. Curr Opin Chem Biol 2023; 75:102328. [PMID: 37236134 PMCID: PMC10524500 DOI: 10.1016/j.cbpa.2023.102328] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023]
Abstract
Selenium is connected to three small molecule antioxidant compounds, ascorbate, α-tocopherol, and ergothioneine. Ascorbate and α-tocopherol are true vitamins, while ergothioneine is a "vitamin-like" compound. Here we review how selenium is connected to all three. Selenium and vitamin E work together as a team to prevent lipid peroxidation. Vitamin E quenches lipid hydroperoxyl radicals and the resulting lipid hydroperoxide is then converted to the lipid alcohol by selenocysteine-containing glutathione peroxidase. Ascorbate reduces the resulting α-tocopheroxyl radical in this reaction back to α-tocopherol with concomitant production of the ascorbyl radical. The ascorbyl radical can be reduced back to ascorbate by selenocysteine-containing thioredoxin reductase. Ergothioneine and ascorbate are both water soluble, small molecule reductants that can reduce free radicals and redox-active metals. Thioredoxin reductase can reduce oxidized forms of ergothioneine. While the biological significance of this is not yet realized, this discovery underscores the centrality of selenium to all three antioxidants.
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Affiliation(s)
- Robert J Hondal
- Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, VT, 05405, USA.
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6
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Cruz MA, Gonzalez Y, Vélez Toro JA, Karimzadeh M, Rubbo A, Morris L, Medam R, Splawn T, Archer M, Fernandes RJ, Dennis JE, Kean TJ. Micronutrient optimization for tissue engineered articular cartilage production of type II collagen. Front Bioeng Biotechnol 2023; 11:1179332. [PMID: 37346792 PMCID: PMC10280293 DOI: 10.3389/fbioe.2023.1179332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/23/2023] [Indexed: 06/23/2023] Open
Abstract
Tissue Engineering of cartilage has been hampered by the inability of engineered tissue to express native levels of type II collagen in vitro. Inadequate levels of type II collagen are, in part, due to a failure to recapitulate the physiological environment in culture. In this study, we engineered primary rabbit chondrocytes to express a secreted reporter, Gaussia Luciferase, driven by the type II collagen promoter, and applied a Design of Experiments approach to assess chondrogenic differentiation in micronutrient-supplemented medium. Using a Response Surface Model, 240 combinations of micronutrients absent in standard chondrogenic differentiation medium, were screened and assessed for type II collagen promoter-driven Gaussia luciferase expression. While the target of this study was to establish a combination of all micronutrients, alpha-linolenic acid, copper, cobalt, chromium, manganese, molybdenum, vitamins A, E, D and B7 were all found to have a significant effect on type II collagen promoter activity. Five conditions containing all micronutrients predicted to produce the greatest luciferase expression were selected for further study. Validation of these conditions in 3D aggregates identified an optimal condition for type II collagen promoter activity. Engineered cartilage grown in this condition, showed a 170% increase in type II collagen expression (Day 22 Luminescence) and in Young's tensile modulus compared to engineered cartilage in basal media alone.Collagen cross-linking analysis confirmed formation of type II-type II collagen and type II-type IX collagen cross-linked heteropolymeric fibrils, characteristic of mature native cartilage. Combining a Design of Experiments approach and secreted reporter cells in 3D aggregate culture enabled a high-throughput platform that can be used to identify more optimal physiological culture parameters for chondrogenesis.
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Affiliation(s)
- Maria A. Cruz
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Yamilet Gonzalez
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Javier A. Vélez Toro
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Makan Karimzadeh
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Anthony Rubbo
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Lauren Morris
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Ramapaada Medam
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
| | - Taylor Splawn
- Baylor College of Medicine, Houston, TX, United States
| | - Marilyn Archer
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, United States
| | - Russell J. Fernandes
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, United States
| | | | - Thomas J. Kean
- Biionix Cluster, Internal Medicine, University of Central Florida College of Medicine, Orlando, FL, United States
- Baylor College of Medicine, Houston, TX, United States
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7
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Mason SA, Parker L, van der Pligt P, Wadley GD. Vitamin C supplementation for diabetes management: A comprehensive narrative review. Free Radic Biol Med 2023; 194:255-283. [PMID: 36526243 DOI: 10.1016/j.freeradbiomed.2022.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022]
Abstract
Growing evidence suggests that vitamin C supplementation may be an effective adjunct therapy in the management of people with diabetes. This paper critically reviews the current evidence on effects of vitamin C supplementation and its potential mechanisms in diabetes management. Evidence from meta-analyses of randomized controlled trials (RCTs) show favourable effects of vitamin C on glycaemic control and blood pressure that may be clinically meaningful, and mixed effects on blood lipids and endothelial function. However, evidence is mostly of low evidence certainty. Emerging evidence is promising for effects of vitamin C supplementation on some diabetes complications, particularly diabetic foot ulcers. However, there is a notable lack of robust and well-designed studies exploring effects of vitamin C as a single compound supplement on diabetes prevention and patient-important outcomes (i.e. prevention and amelioration of diabetes complications). RCTs are also required to investigate potential preventative or ameliorative effects of vitamin C on gestational diabetes outcomes. Oral vitamin C doses of 500-1000 mg per day are potentially effective, safe, and affordable for many individuals with diabetes. However, personalisation of supplementation regimens that consider factors such as vitamin C status, disease status, current glycaemic control, vitamin C intake, redox status, and genotype is important to optimize vitamin C's therapeutic effects safely. Finally, given a high prevalence of vitamin C deficiency in patients with complications, it is recommended that plasma vitamin C concentration be measured and monitored in the clinic setting.
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Affiliation(s)
- Shaun A Mason
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia.
| | - Lewan Parker
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Paige van der Pligt
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia; Department of Nutrition and Dietetics, Western Health, Footscray, Australia
| | - Glenn D Wadley
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
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8
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San-Martín-Martínez D, Serrano-Lemus D, Cornejo V, Gajardo AIJ, Rodrigo R. Pharmacological Basis for Abrogating Myocardial Reperfusion Injury Through a Multi-Target Combined Antioxidant Therapy. Clin Pharmacokinet 2022; 61:1203-1218. [DOI: 10.1007/s40262-022-01151-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2022] [Indexed: 11/29/2022]
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9
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Miyata H, Toyoda Y, Takada T, Hiragi T, Kubota Y, Shigesawa R, Koyama R, Ikegaya Y, Suzuki H. Identification of an exporter that regulates vitamin C supply from blood to the brain. iScience 2022; 25:103642. [PMID: 35106468 PMCID: PMC8786643 DOI: 10.1016/j.isci.2021.103642] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 11/12/2021] [Accepted: 12/14/2021] [Indexed: 01/09/2023] Open
Abstract
Vitamin C (VC) distribution in our body requires VC transporters. However, mammalian VC exporters are yet to be identified. Herein, to unravel this long-standing mystery, we focused on the pathways whereby VC moves from blood to the brain, which should require a VC entrance and exit system composed of an importer and a latent exporter. Via cell-based transport analyses of VC efflux and using knockout mice generated via the CRISPR-Cas9 system, we identified GLUT12/SLC2A12 as a physiologically important VC efflux protein expressed in the choroid plexus; Glut12/Slc2a12 knockout halved the cerebral VC levels, markedly increased VC accumulation in the choroid plexus, and reduced the cerebrospinal fluid VC levels. These findings facilitate our understanding of VC regulation and the physiological impact of VC in our body. A long-standing mystery in vitamin C handling in mammalians was uncovered GLUT12 was identified as a physiologically important vitamin C efflux protein—VCEP GLUT12 is expressed in the choroid plexus and acts as a vitamin C exporter Glut12 knockout halved the cerebral vitamin C levels in mice
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Affiliation(s)
- Hiroshi Miyata
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Yu Toyoda
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Tappei Takada
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Toshimitsu Hiragi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yu Kubota
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Ryuichiro Shigesawa
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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10
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Vitamin C for sepsis intervention: from redox biochemistry to clinical medicine. Mol Cell Biochem 2021; 476:4449-4460. [PMID: 34478032 PMCID: PMC8413356 DOI: 10.1007/s11010-021-04240-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/29/2021] [Indexed: 12/27/2022]
Abstract
Vitamin C, also known as ascorbic acid or ascorbate, is a water-soluble vitamin synthesized in plants as well as in animals except humans and several other animal species. Humans obtain vitamin C from dietary sources and via vitamin supplementation. Vitamin C possesses important biological functions, including serving as a cofactor for many enzymes, acting as an antioxidant and anti-inflammatory compound, and participating in regulating stem cell biology and epigenetics. The multifunctional nature of vitamin C contributes to its essentialness in maintaining and safeguarding physiological homeostasis, especially regulation of immunity and inflammatory responses. In this context, vitamin C has been investigated for its efficacy in treating diverse inflammatory disorders, including sepsis, one of the major causes of death globally and for which currently there is no cure. Accordingly, this Mini-Review surveys recent major research findings on the effectiveness of vitamin C and the underling molecular mechanisms in sepsis intervention in both experimental animal models and randomized controlled trials. To set a stage for discussing the effects and mechanisms of vitamin C in sepsis intervention, this Mini-Review begins with an overview of vitamin C redox biochemistry and its multifunctional properties.
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11
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Polutchko SK, Glime GNE, Demmig-Adams B. Synergistic Action of Membrane-Bound and Water-Soluble Antioxidants in Neuroprotection. Molecules 2021; 26:5385. [PMID: 34500818 PMCID: PMC8434335 DOI: 10.3390/molecules26175385] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 12/30/2022] Open
Abstract
Prevention of neurodegeneration during aging, and support of optimal brain function throughout the lifespan, requires protection of membrane structure and function. We review the synergistic action of different classes of dietary micronutrients, as well as further synergistic contributions from exercise and stress reduction, in supporting membrane structure and function. We address membrane-associated inflammation involving reactive oxygen species (ROS) that produce immune regulators from polyunsaturated fatty acids (PUFAs) of membrane phospholipids. The potential of dietary micronutrients to maintain membrane fluidity and prevent chronic inflammation is examined with a focus on synergistically acting membrane-soluble components (zeaxanthin, lutein, vitamin E, and omega-3 PUFAs) and water-soluble components (vitamin C and various phenolics). These different classes of micronutrients apparently operate in a series of intertwined oxidation-reduction cycles to protect membrane function and prevent chronic inflammation. At this time, it appears that combinations of a balanced diet with regular moderate exercise and stress-reduction practices are particularly beneficial. Effective whole-food-based diets include the Mediterranean and the MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay diet, where DASH stands for Dietary Approaches to Stop Hypertension).
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Affiliation(s)
| | | | - Barbara Demmig-Adams
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA; (S.K.P.); (G.N.E.G.)
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12
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High-Dose Vitamin C in Advanced-Stage Cancer Patients. Nutrients 2021; 13:nu13030735. [PMID: 33652579 PMCID: PMC7996511 DOI: 10.3390/nu13030735] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/03/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023] Open
Abstract
High-dose intravenously administered vitamin C (IVC) is widely used in cancer patients by complementary and alternative medicine practitioners. The most frequent indications for IVC therapy result from the belief in its effectiveness as a potent anti-cancer agent which additionally enhances chemosensitivity of cancer cells and reduces chemotherapy-related toxicities and fatigue intensity. In this narrative review, we decided to deal with this issue, trying to answer the question whether there is any scientific evidence supporting the rationale for application of high-dose IVC therapy in advanced-stage cancer patients. Although results obtained from preclinical studies demonstrated that millimolar ascorbate plasma concentrations achievable only after IVC administration were cytotoxic to fast-growing malignant cells and inhibited tumor growth as well as prolonged the survival of laboratory animals, such positive effects were not found in human studies with advanced-stage cancer patients. We also have not found the rationale for the use of IVC to increase the effectiveness of chemotherapy and to reduce the chemotherapy-induced toxicity in the above mentioned group. Nevertheless, in palliative care, high-dose IVC might be considered as a therapy improving the quality of life and reducing cancer-related symptoms, such as fatigue and bone pain. However, because of the absence of placebo-controlled randomized trials on IVC efficacy in advanced-stage cancer patients, the placebo effect cannot be excluded.
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13
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Lohan SB, Ivanov D, Schüler N, Berger B, Zastrow L, Lademann J, Meinke MC. Switching from healthy to unhealthy oxidative stress - does the radical type can be used as an indicator? Free Radic Biol Med 2021; 162:401-411. [PMID: 33137467 DOI: 10.1016/j.freeradbiomed.2020.10.319] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/08/2020] [Accepted: 10/26/2020] [Indexed: 10/23/2022]
Abstract
Ultraviolet (UV) radiation leads to the formation of free radicals, which may cause immunological modulations, skin aging or skin cancer. Sunlight exposure in the UVA region according to CIE 85 promotes almost 46% of radical formation in skin. A critical radical concentration characterized by the inversion of the domination of primary ROS (reactive oxygen species) to an excess of secondary LOS (lipid oxygen species) is proven for the spectral regions UV and or VIS light and is intended to be a marker for an imbalance in the redox system, which can no longer compensate harmful effects. To investigate whether this transition point is also universally valid for one spectral region, the radical formation during and after targeted UVA in situ-irradiation at 365 ± 5 nm and three different irradiances (31, 94 and 244 mW/cm2) was investigated in ex vivo porcine skin using x-band electron paramagnetic resonance (EPR) spectroscopy. The quantification was performed with the spin probe 3-(carboxy)-2,2,5,5-tetramethylpyrrolidin-1-oxyl (PCA), the spin trap 5,5-Dimethyl-1-Pyrroline-N-Oxide (DMPO) was used to characterize the radical species. Furthermore, the viability of the skin cells after irradiation was controlled by an MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, skin integrity was examined by histological analysis. A significant dose dependence in the radical formation is given at higher irradiance. The transition point was detected in the range of 0.5 MED after irradiation with the highest irradiance. From this point on the proportion of LOS increases with increasing dose and the proportion of ROS decreases. After switching off the UVA irradiation no further quantitative changes were detected, but rapid changes in the radical pattern were observed demonstrating the importance of in situ irradiation during the use of spin traps. Heat-pre-stressed skin showed more LOS than ROS already at the beginning of the irradiation, leading to the assumption that the transition point to the distress-level has already been reached. In summary, a postulated transition point could be verified for the UVA spectral region using only one spin trap combined with in-situ irradiation. A certain degree of stress is necessary to detect an inversion of the ratio of ROS to LOS. This reversal indicates an imbalance in the redox status. However, at low intensities no changes at all in radical pattern appeared over time (dose), probably it can be compensated by adaptation processes of the skin.
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Affiliation(s)
- S B Lohan
- Charité - Universitätsmedizin Berlin, corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Berlin, Germany.
| | - D Ivanov
- Charité - Universitätsmedizin Berlin, corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Berlin, Germany
| | - N Schüler
- Freiberg Instruments GmbH, Freiberg, Germany
| | - B Berger
- Freiberg Instruments GmbH, Freiberg, Germany
| | - L Zastrow
- Charité - Universitätsmedizin Berlin, corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Berlin, Germany
| | - J Lademann
- Charité - Universitätsmedizin Berlin, corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Berlin, Germany
| | - M C Meinke
- Charité - Universitätsmedizin Berlin, corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Dermatology, Venerology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Berlin, Germany
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14
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Margaritelis NV, Paschalis V, Theodorou AA, Kyparos A, Nikolaidis MG. Redox basis of exercise physiology. Redox Biol 2020; 35:101499. [PMID: 32192916 PMCID: PMC7284946 DOI: 10.1016/j.redox.2020.101499] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/20/2020] [Accepted: 03/05/2020] [Indexed: 12/15/2022] Open
Abstract
Redox reactions control fundamental processes of human biology. Therefore, it is safe to assume that the responses and adaptations to exercise are, at least in part, mediated by redox reactions. In this review, we are trying to show that redox reactions are the basis of exercise physiology by outlining the redox signaling pathways that regulate four characteristic acute exercise-induced responses (muscle contractile function, glucose uptake, blood flow and bioenergetics) and four chronic exercise-induced adaptations (mitochondrial biogenesis, muscle hypertrophy, angiogenesis and redox homeostasis). Based on our analysis, we argue that redox regulation should be acknowledged as central to exercise physiology.
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Affiliation(s)
- N V Margaritelis
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece; Dialysis Unit, 424 General Military Hospital of Thessaloniki, Thessaloniki, Greece.
| | - V Paschalis
- School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - A A Theodorou
- Department of Life Sciences, School of Sciences, European University Cyprus, Nicosia, Cyprus
| | - A Kyparos
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - M G Nikolaidis
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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15
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Saso L, Gürer-Orhan H, Stepanić V. Modulators of Oxidative Stress: Chemical and Pharmacological Aspects. Antioxidants (Basel) 2020; 9:antiox9080657. [PMID: 32722041 PMCID: PMC7465287 DOI: 10.3390/antiox9080657] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 07/22/2020] [Indexed: 11/26/2022] Open
Affiliation(s)
- Luciano Saso
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University, 00185 Rome, Italy;
| | - Hande Gürer-Orhan
- Toxicology Department, Faculty of Pharmacy, Ege University, Izmir 35040, Turkey;
| | - Višnja Stepanić
- Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
- Correspondence: ; Tel.: +385-1-457-1356
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16
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Lykkesfeldt J. On the effect of vitamin C intake on human health: How to (mis)interprete the clinical evidence. Redox Biol 2020; 34:101532. [PMID: 32535545 PMCID: PMC7296342 DOI: 10.1016/j.redox.2020.101532] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/30/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023] Open
Abstract
For decades, the potential beneficial effect of vitamin C on human health-beyond that of preventing scurvy-has been subject of much controversy. Hundreds of articles have appeared either in support of increased vitamin C intake through diet or supplements or rejecting the hypothesis that increased intake of vitamin C or supplementation may influence morbidity and mortality. The chemistry and pharmacology of vitamin C is complex and has unfortunately rarely been taken into account when designing clinical studies testing its effect on human health. However, ignoring its chemical lability, dose-dependent absorption and elimination kinetics, distribution via active transport, or complex dose-concentration-response relationships inevitably leads to poor study designs, inadequate inclusion and exclusion criteria and misinterpretation of results. The present review outlines the differences in vitamin C pharmacokinetics compared to normal low molecular weight drugs, focusses on potential pitfalls in study design and data interpretation, and re-examines major clinical studies of vitamin C in light of these.
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Affiliation(s)
- Jens Lykkesfeldt
- Faculty of Health & Medical Sciences, University of Copenhagen, DK-1870, Frederiksberg C, Denmark.
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17
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Oyagbemi AA, Omobowale TO, Adejumobi OA, Owolabi AM, Ogunpolu BS, Falayi OO, Hassan FO, Ogunmiluyi IO, Asenuga ER, Ola-Davies OE, Soetan KO, Saba AB, Adedapo AA, Nkadimeng SM, McGaw LJ, Oguntibeju OO, Yakubu MA. Antihypertensive power of Naringenin is mediated via attenuation of mineralocorticoid receptor (MCR)/ angiotensin converting enzyme (ACE)/ kidney injury molecule (Kim-1) signaling pathway. Eur J Pharmacol 2020; 880:173142. [PMID: 32422184 DOI: 10.1016/j.ejphar.2020.173142] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 02/08/2023]
Abstract
Hypertension is a condition with chronic elevation of blood pressure and a common preventable risk factor for cardiovascular disease with attendant global morbidity and mortality. The present study investigated the novel antihypertensive and neuroprotective effect of Naringenin on L-NG-Nitro arginine methyl ester (L-NAME) induced hypertension together with possible molecular mechanism of action. Rats were divided into four groups. Rats in Group A were normotensive. The hypertensive group (Group B) received 40 mg/kg) of L-NAME alone while Groups C and D were concurrently administered Naringenin (50 mg/kg) or Lisinopril (10 mg/Kg) together with L-NAME orally for 3 weeks. Blood pressure parameters, markers of oxidative stress and renal damage were measured. The immunohistochemistry of kidney injury molecule 1, mineralocorticoid receptor and angiotensin converting enzyme were also determined. Results indicated significant increases in malondialdehyde, advanced oxidation protein products, protein carbonyl contents and decrease in serum nitric oxide bioavailability in hypertensive rats. Furthermore, there were significant increases in serum myeloperoxidase, urinary creatinine, albumin and blood urea nitrogen in hypertensive rats in comparison to hypertensive rats treated with either Naringenin or Lisinopril. Immunohistochemistry reveal significant expressions of kidney injury molecule 1, mineralocorticoid receptor and angiotensin converting enzyme in hypertensive rats. However, co-treatment with either Naringenin or Lisinopril mitigated both renal and neuronal oxidative stress, normalized blood pressure and lowered the expressions of kidney injury molecule 1, mineralocorticoid receptor and angiotensin converting enzyme. Collectively, Naringenin offered a novel antihypertensive and neuroprotective effect through down regulation of kidney injury molecule 1, mineralocorticoid receptor and angiotensin converting enzyme.
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Affiliation(s)
- Ademola Adetokunbo Oyagbemi
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Ibadan, Nigeria.
| | | | | | - Abiodun Mary Owolabi
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Blessing Seun Ogunpolu
- Department of Veterinary Medicine, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Olufunke Olubunmi Falayi
- Department of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Fasilat Oluwakemi Hassan
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | | | - Ebunoluwa Racheal Asenuga
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Benin, Nigeria
| | - Olufunke Eunice Ola-Davies
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Kehinde Olugboyega Soetan
- Department of Veterinary Physiology and Biochemistry, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Adebowale Benard Saba
- Department of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Adeolu Alex Adedapo
- Department of Veterinary Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Ibadan, Nigeria
| | - Sanah Malomile Nkadimeng
- Phytomedicine Programme, Department of Paraclinical Science, University of Pretoria Faculty of Veterinary Science, Old Soutpan Road, Onderstepoort, 0110, South Africa
| | - Lyndy Joy McGaw
- Phytomedicine Programme, Department of Paraclinical Science, University of Pretoria Faculty of Veterinary Science, Old Soutpan Road, Onderstepoort, 0110, South Africa
| | - Oluwafemi Omoniyi Oguntibeju
- Phytomedicine and Phytochemistry Group, Department of Biomedical Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Bellville, 7535, South Africa
| | - Momoh Audu Yakubu
- Department of Environmental & Interdisciplinary Sciences, College of Science, Engineering & Technology, Texas Southern University, Houston, TX, USA
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18
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The Association of Ascorbic Acid, Deferoxamine and N-Acetylcysteine Improves Cardiac Fibroblast Viability and Cellular Function Associated with Tissue Repair Damaged by Simulated Ischemia/Reperfusion. Antioxidants (Basel) 2019; 8:antiox8120614. [PMID: 31817022 PMCID: PMC6943610 DOI: 10.3390/antiox8120614] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 11/18/2019] [Accepted: 11/26/2019] [Indexed: 12/16/2022] Open
Abstract
Acute myocardial infarction is one of the leading causes of death worldwide and thus, an extensively studied disease. Nonetheless, the effects of ischemia/reperfusion injury elicited by oxidative stress on cardiac fibroblast function associated with tissue repair are not completely understood. Ascorbic acid, deferoxamine, and N-acetylcysteine (A/D/N) are antioxidants with known cardioprotective effects, but the potential beneficial effects of combining these antioxidants in the tissue repair properties of cardiac fibroblasts remain unknown. Thus, the aim of this study was to evaluate whether the pharmacological association of these antioxidants, at low concentrations, could confer protection to cardiac fibroblasts against simulated ischemia/reperfusion injury. To test this, neonatal rat cardiac fibroblasts were subjected to simulated ischemia/reperfusion in the presence or absence of A/D/N treatment added at the beginning of simulated reperfusion. Cell viability was assessed using trypan blue staining, and intracellular reactive oxygen species (ROS) production was assessed using a 2′,7′-dichlorofluorescin diacetate probe. Cell death was measured by flow cytometry using propidium iodide. Cell signaling mechanisms, differentiation into myofibroblasts and pro-collagen I production were determined by Western blot, whereas migration was evaluated using the wound healing assay. Our results show that A/D/N association using a low concentration of each antioxidant increased cardiac fibroblast viability, but that their separate administration did not provide protection. In addition, A/D/N association attenuated oxidative stress triggered by simulated ischemia/reperfusion, induced phosphorylation of pro-survival extracellular-signal-regulated kinases 1/2 (ERK1/2) and PKB (protein kinase B)/Akt, and decreased phosphorylation of the pro-apoptotic proteins p38- mitogen-activated protein kinase (p38-MAPK) and c-Jun-N-terminal kinase (JNK). Moreover, treatment with A/D/N also reduced reperfusion-induced apoptosis, evidenced by a decrease in the sub-G1 population, lower fragmentation of pro-caspases 9 and 3, as well as increased B-cell lymphoma-extra large protein (Bcl-xL)/Bcl-2-associated X protein (Bax) ratio. Furthermore, simulated ischemia/reperfusion abolished serum-induced migration, TGF-β1 (transforming growth factor beta 1)-mediated cardiac fibroblast-to-cardiac myofibroblast differentiation, and angiotensin II-induced pro-collagen I synthesis, but these effects were prevented by treatment with A/D/N. In conclusion, this is the first study where a pharmacological combination of A/D/N, at low concentrations, protected cardiac fibroblast viability and function after simulated ischemia/reperfusion, and thereby represents a novel therapeutic approach for cardioprotection.
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El Banna N, Hatem E, Heneman-Masurel A, Léger T, Baïlle D, Vernis L, Garcia C, Martineau S, Dupuy C, Vagner S, Camadro JM, Huang ME. Redox modifications of cysteine-containing proteins, cell cycle arrest and translation inhibition: Involvement in vitamin C-induced breast cancer cell death. Redox Biol 2019; 26:101290. [PMID: 31412312 PMCID: PMC6831881 DOI: 10.1016/j.redox.2019.101290] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/28/2019] [Accepted: 07/31/2019] [Indexed: 12/13/2022] Open
Abstract
Vitamin C (VitC) possesses pro-oxidant properties at high pharmacologic concentrations which favor repurposing VitC as an anti-cancer therapeutic agent. However, redox-based anticancer properties of VitC are yet partially understood. We examined the difference between the reduced and oxidized forms of VitC, ascorbic acid (AA) and dehydroascorbic acid (DHA), in terms of cytotoxicity and redox mechanisms toward breast cancer cells. Our data showed that AA displayed higher cytotoxicity towards triple-negative breast cancer (TNBC) cell lines in vitro than DHA. AA exhibited a similar cytotoxicity on non-TNBC cells, while only a minor detrimental effect on noncancerous cells. Using MDA-MB-231, a representative TNBC cell line, we observed that AA- and DHA-induced cytotoxicity were linked to cellular redox-state alterations. Hydrogen peroxide (H2O2) accumulation in the extracellular medium and in different intracellular compartments, and to a lesser degree, intracellular glutathione oxidation, played a key role in AA-induced cytotoxicity. In contrast, DHA affected glutathione oxidation and had less cytotoxicity. A "redoxome" approach revealed that AA treatment altered the redox state of key antioxidants and a number of cysteine-containing proteins including many nucleic acid binding proteins and proteins involved in RNA and DNA metabolisms and in energetic processes. We showed that cell cycle arrest and translation inhibition were associated with AA-induced cytotoxicity. Finally, bioinformatics analysis and biological experiments identified that peroxiredoxin 1 (PRDX1) expression levels correlated with AA differential cytotoxicity in breast cancer cells, suggesting a potential predictive value of PRDX1. This study provides insight into the redox-based mechanisms of VitC anticancer activity, indicating that pharmacologic doses of VitC and VitC-based rational drug combinations could be novel therapeutic opportunities for triple-negative breast cancer.
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Affiliation(s)
- Nadine El Banna
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Elie Hatem
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Amélie Heneman-Masurel
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Thibaut Léger
- Institut Jacques Monod, CNRS UMR 7592, Mass Spectrometry Laboratory, Université Paris Diderot, Paris, France
| | - Dorothée Baïlle
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Laurence Vernis
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Camille Garcia
- Institut Jacques Monod, CNRS UMR 7592, Mass Spectrometry Laboratory, Université Paris Diderot, Paris, France
| | - Sylvain Martineau
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Corinne Dupuy
- Institut Gustave Roussy, CNRS UMR 8200, Université Paris-Sud, Villejuif, France
| | - Stéphan Vagner
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Jean-Michel Camadro
- Institut Jacques Monod, CNRS UMR 7592, Mass Spectrometry Laboratory, Université Paris Diderot, Paris, France
| | - Meng-Er Huang
- Institut Curie, PSL Research University, CNRS UMR 3348, Université Paris-Sud, Université Paris-Saclay, Orsay, France.
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20
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Peña E, Roa FJ, Inostroza E, Sotomayor K, González M, Gutierrez-Castro FA, Maurin M, Sweet K, Labrousse C, Gatica M, Aylwin CF, Mendoza P, Maldonado M, Delgado C, Madariaga J, Panes J, Silva-Grecchi T, Concha II, Moraga-Cid G, Reyes AM, Muñoz-Montesino C, Vera JC, Rivas CI. Increased expression of mitochondrial sodium-coupled ascorbic acid transporter-2 (mitSVCT2) as a central feature in breast cancer. Free Radic Biol Med 2019; 135:283-292. [PMID: 30902760 DOI: 10.1016/j.freeradbiomed.2019.03.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 03/07/2019] [Accepted: 03/12/2019] [Indexed: 12/20/2022]
Abstract
The potential role of vitamin C in cancer prevention and treatment remains controversial. While normal human cells obtain vitamin C as ascorbic acid, the prevalent form of vitamin C in vivo, the uptake mechanisms by which cancer cells acquire vitamin C has remained unclear. The aim of this study is to characterize how breast cancer cells acquire vitamin C. For this, we determined the expression of vitamin C transporters in normal and breast cancer tissue samples, and in ZR-75, MCF-7, MDA-231 and MDA-468 breast cancer cell lines. At the same time, reduced (AA) and oxidized (DHA) forms of vitamin C uptake experiments were performed in all cell lines. We show here that human breast cancer tissues differentially express a form of SVCT2 transporter, that is systematically absent in normal breast tissues and it is increased in breast tumors. In fact, estrogen receptor negative breast cancer tissue, exhibit the most elevated SVCT2 expression levels. Despite this, our analysis in breast cancer cell lines showed that these cells are not able to uptake ascorbic acid and depend on glucose transporter for the acquisition of vitamin C by a bystander effect. This is consistent with our observations that this form of SVCT2 is completely absent from the plasma membrane and is overexpressed in mitochondria of breast cancer cells, where it mediates ascorbic acid transport. This work shows that breast cancer cells acquire vitamin C in its oxidized form and are capable of accumulated high concentrations of the reduced form. Augmented expression of an SVCT2 mitochondrial form appears to be a common hallmark across all human cancers and might have implications in cancer cells survival capacity against pro-oxidant environments.
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Affiliation(s)
- Eduardo Peña
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Francisco J Roa
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Eveling Inostroza
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Kirsty Sotomayor
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Mauricio González
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Francisco A Gutierrez-Castro
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Michelle Maurin
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Karen Sweet
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Claire Labrousse
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Marcell Gatica
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Carlos F Aylwin
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Pamela Mendoza
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Mafalda Maldonado
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Carolina Delgado
- Departamento de Especialidades Médicas, Facultad de Medicina, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Jaime Madariaga
- Departamento de Especialidades Médicas, Facultad de Medicina, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Jessica Panes
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Tiare Silva-Grecchi
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Ilona I Concha
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, PO Box 567, Valdivia, Chile
| | - Gustavo Moraga-Cid
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Alejandro M Reyes
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Campus Isla Teja, PO Box 567, Valdivia, Chile
| | - Carola Muñoz-Montesino
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile.
| | - Juan Carlos Vera
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile
| | - Coralia I Rivas
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Barrio Universitario s/n, PO Box 160C, Concepción, Chile.
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Ito S, Hyodo F. Dynamic nuclear polarization-magnetic resonance imaging at low ESR irradiation frequency for ascorbyl free radicals. Sci Rep 2016; 6:21407. [PMID: 26892591 PMCID: PMC4759784 DOI: 10.1038/srep21407] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/22/2016] [Indexed: 11/14/2022] Open
Abstract
Highly water-soluble ubiquinone-0 (CoQ0) reacts with ascorbate monoanion (Asc) to mediate the production of ascorbyl free radicals (AFR). Using aqueous reaction mixture of CoQ0 and Asc, we obtained positively enhanced dynamic nuclear polarization (DNP)-magnetic resonance (MR) images of the AFR at low frequency (ranging from 515 to 530 MHz) of electron spin resonance (ESR) irradiation. The shape of the determined DNP spectrum was similar to ESR absorption spectra with doublet spectral peaks. The relative locational relationship of spectral peaks in the DNP spectra between the AFR (520 and 525 MHz), 14N-labeled carbamoyl-PROXYL (14N-CmP) (526.5 MHz), and Oxo63 (522 MHz) was different from that in the X-band ESR spectra, but were similar to that in the 300-MHz ESR spectra. The ratio of DNP enhancement to radical concentration for the AFR was higher than those for 14N-CmP, Oxo63, and flavin semiquinone radicals. The spectroscopic DNP properties observed for the AFR were essentially the same as those for AFR mediated by pyrroloquinoline quinone. Moreover, we made a success of in vivo DNP-MR imaging of the CoQ0-mediated AFR which was administered by the subcutaneous and oral injections as an imaging probe.
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Affiliation(s)
- Shinji Ito
- Innovation Center for Medical Redox Navigation, Kyushu University, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
| | - Fuminori Hyodo
- Innovation Center for Medical Redox Navigation, Kyushu University, Maidashi, Higashi-ku, Fukuoka 812-8582, Japan
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22
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Cazeau RM, Huang H, Bauer JA, Hoffman RP. Effect of Vitamins C and E on Endothelial Function in Type 1 Diabetes Mellitus. J Diabetes Res 2016; 2016:3271293. [PMID: 26783536 PMCID: PMC4689966 DOI: 10.1155/2016/3271293] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 07/14/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND/OBJECTIVES Endothelial dysfunction due to hyperglycemia-induced oxidative damage is an important predictor of future cardiovascular risk in patients with type 1 diabetes mellitus (T1DM) and is present in adolescent T1DM. We hypothesized that combined treatment with the antioxidant vitamins C and E might improve endothelial function (EF) and other biochemical risk factors in adolescents with T1DM. SUBJECTS/METHODS Open-label antioxidant supplementation was given for six weeks with endpoint measurements collected at baseline and study completion. Endpoints measured included EF and plasma measurements of biochemical endothelial risk. RESULTS Two males and 7 females were studied. Mean age was 12.9 ± 0.9 yrs; mean T1DM duration was 5.5 ± 2.5 yrs; mean BMI was 22.1 ± 3.8 kg/m(2); and mean hemoglobin A1c was 9.3 ± 1.1%. No differences were found for EF, high sensitivity CRP, total antioxidant capacity, adiponectin, or endothelial progenitor cells (EPCs) between before and after combined vitamin C and E therapy. CONCLUSIONS Our negative study results do not support previous findings of decreased oxidative damage, improved endothelial function, and increased vascular repair capacity with antioxidant therapy. Longer term studies may be needed to determine the effects, if any, of combined antioxidant therapy on EPCs, EF, and markers of micro- and macrovascular complications in T1DM.
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Affiliation(s)
- Rachel-Marie Cazeau
- Section of Endocrinology, Metabolism and Diabetes, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
- Division of Pediatric Endocrinology, Metabolism and Diabetes, Department of Pediatrics, The Clinical Research Center, The Ohio State University College of Medicine and Public Health, Columbus, OH 43205, USA
- *Rachel-Marie Cazeau:
| | - Hong Huang
- Department of Pediatrics, University of Kentucky, Lexington, KY 40506, USA
| | - John A. Bauer
- Department of Pediatrics, University of Kentucky, Lexington, KY 40506, USA
| | - Robert P. Hoffman
- Section of Endocrinology, Metabolism and Diabetes, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
- Division of Pediatric Endocrinology, Metabolism and Diabetes, Department of Pediatrics, The Clinical Research Center, The Ohio State University College of Medicine and Public Health, Columbus, OH 43205, USA
- The Research Institute, Nationwide Children's Hospital, Columbus, OH 43205, USA
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Lane DJR, Richardson DR. The active role of vitamin C in mammalian iron metabolism: much more than just enhanced iron absorption! Free Radic Biol Med 2014; 75:69-83. [PMID: 25048971 DOI: 10.1016/j.freeradbiomed.2014.07.007] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/04/2014] [Accepted: 07/08/2014] [Indexed: 01/18/2023]
Abstract
Ascorbate is a cofactor in numerous metabolic reactions. Humans cannot synthesize ascorbate owing to inactivation of the gene encoding the enzyme l-gulono-γ-lactone oxidase, which is essential for ascorbate synthesis. Accumulating evidence strongly suggests that in addition to the known ability of dietary ascorbate to enhance nonheme iron absorption in the gut, ascorbate within mammalian systems can regulate cellular iron uptake and metabolism. Ascorbate modulates iron metabolism by stimulating ferritin synthesis, inhibiting lysosomal ferritin degradation, and decreasing cellular iron efflux. Furthermore, ascorbate cycling across the plasma membrane is responsible for ascorbate-stimulated iron uptake from low-molecular-weight iron-citrate complexes, which are prominent in the plasma of individuals with iron-overload disorders. Importantly, this iron-uptake pathway is of particular relevance to astrocyte brain iron metabolism and tissue iron loading in disorders such as hereditary hemochromatosis and β-thalassemia. Recent evidence also indicates that ascorbate is a novel modulator of the classical transferrin-iron uptake pathway, which provides almost all iron for cellular demands and erythropoiesis under physiological conditions. Ascorbate acts to stimulate transferrin-dependent iron uptake by an intracellular reductive mechanism, strongly suggesting that it may act to stimulate iron mobilization from the endosome. The ability of ascorbate to regulate transferrin iron uptake could help explain the metabolic defect that contributes to ascorbate-deficiency-induced anemia.
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Affiliation(s)
- Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
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Abstract
It has been demonstrated that redox homeostasis is important in the pathophysiology of several human diseases, including cardiovascular diseases. In this respect, genetic polymorphism, nutritional and environmental factors, age, lifestyle and physical activity may account for variable antioxidant defenses, which may be more or less effective at counteracting oxidative damage. Since accumulating oxidative damage may be associated with several pathologic conditions, including different cardiovascular diseases, prevention of oxidative stress appears to be a promising approach to improve such diseases. Exercise training, diets rich in antioxidants and a good control of blood glucose and lipid levels help to strengthen the physiologic antioxidant defense system, perhaps coupled to drugs capable of increasing the nitric oxide bioavailability and decreasing superoxide production. Within the next few years other therapeutic approaches will be available, such as gene therapy, which will prove to be even more effective but devoid of several important systemic side effects.
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Affiliation(s)
- Paolo Abrescia
- University of Naples Federico II, Department of General and Environmental Physiology, Via Mezzocannone 8, 80134 Naples, Italy.
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25
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Nualart F, Mack L, García A, Cisternas P, Bongarzone ER, Heitzer M, Jara N, Martínez F, Ferrada L, Espinoza F, Baeza V, Salazar K. Vitamin C Transporters, Recycling and the Bystander Effect in the Nervous System: SVCT2 versus Gluts. ACTA ACUST UNITED AC 2014; 4:209. [PMID: 25110615 PMCID: PMC4126260 DOI: 10.4172/2157-7633.1000209] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vitamin C is an essential micronutrient in the human diet; its deficiency leads to a number of symptoms and ultimately death. After entry into cells within the central nervous system (CNS) through sodium vitamin C transporters (SVCTs) and facilitative glucose transporters (GLUTs), vitamin C functions as a neuromodulator, enzymatic cofactor, and reactive oxygen species (ROS) scavenger; it also stimulates differentiation. In this review, we will compare the molecular and structural aspects of vitamin C and glucose transporters and their expression in endothelial or choroid plexus cells, which form part of the blood-brain barrier and blood-cerebrospinal fluid (CSF) barrier, respectively. Additionally, we will describe SVCT and GLUT expression in different cells of the brain as well as SVCT2 distribution in tanycytes and astrocytes of the hypothalamic region. Finally, we will describe vitamin C recycling in the brain, which is mediated by a metabolic interaction between astrocytes and neurons, and the role of the "bystander effect" in the recycling mechanism of vitamin C in both normal and pathological conditions.
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Affiliation(s)
- Francisco Nualart
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Lauren Mack
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Andrea García
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Pedro Cisternas
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Ernesto R Bongarzone
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, USA
| | - Marjet Heitzer
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Nery Jara
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Fernando Martínez
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Luciano Ferrada
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Francisca Espinoza
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Victor Baeza
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
| | - Katterine Salazar
- Center for Advanced Microscopy CMA BIO-BIO, Neurobiology and Stem cell Laboratory, Concepcion University, Chile
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26
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Rodemeister S, Duquesne M, Adolph M, Nohr D, Biesalski HK, Unertl K. Massive and long-lasting decrease in vitamin C plasma levels as a consequence of extracorporeal circulation. Nutrition 2013; 30:673-8. [PMID: 24631388 DOI: 10.1016/j.nut.2013.10.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 10/29/2013] [Accepted: 10/30/2013] [Indexed: 02/07/2023]
Abstract
OBJECTIVE The use of cardiopulmonary bypass (CPB) is suggested to induce oxidative stress, reflected by an imbalance between prooxidant and antioxidant substances. The majority of studies published have either focused on only one aspect (prooxidant or antioxidant side) or covered only a short observation period. Therefore, the aim of this study was to investigate the long-term effects of CPB on the balance of prooxidative markers and antioxidant substances in one single group of patients, being able to estimate the degree of oxidative stress. METHODS Blood samples were taken from 29 patients undergoing cardiovascular surgery beginning the day before surgery through postoperative day 6 (discharge). Plasma concentrations of vitamins C (total ascorbic acid) and E and malondialdehyde were measured by high-performance liquid chromatography. Plasma levels of ascorbyl free radical were determined using electron paramagnetic resonance spectroscopy. RESULTS The study showed a significant decrease in vitamin C plasma levels during CPB without any recovery of vitamin C up to the time of discharge. Furthermore, CPB induced a significant increase in malondialdehyde plasma concentrations immediately after unclamping, accompanied by a significant increase in the ascorbyl free radical to total ascorbic acid ratio. The latter stayed elevated until the end of observation. CONCLUSIONS Our findings indicate that the oxidative stress event after CPB can be divided into two phases: Immediately after reperfusion, a massive oxidative stress occurs, reflected by the increase in malondialdehyde. During convalescence, there must be an ongoing situation of oxidative stress, especially in the water-soluble compartment, leading to the consumption of vitamin C. Because the main antioxidant substance, vitamin C, did not increase again over the entire observation period, supplementation should be given consideration.
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Affiliation(s)
- Sandra Rodemeister
- Institute for Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, Germany.
| | - Mathieu Duquesne
- Centre hospitalier universitaire Nice, service d'anesthésie-réanimation, Nice, France
| | - Michael Adolph
- Department of Anaesthesiology and Intensive Care Medicine, University of Tuebingen, Tuebingen, Germany
| | - Donatus Nohr
- Institute for Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, Germany
| | - Hans K Biesalski
- Institute for Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, Germany
| | - Klaus Unertl
- Department of Anaesthesiology and Intensive Care Medicine, University of Tuebingen, Tuebingen, Germany
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27
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Abstract
Hypertension is a leading cause of morbidity and mortality worldwide. Individuals with hypertension are at an increased risk for stroke, heart disease and kidney failure. Essential hypertension results from a combination of genetic and lifestyle factors. One such lifestyle factor is diet, and its role in the control of blood pressure has come under much scrutiny. Just as increased salt and sugar are known to elevate blood pressure, other dietary factors may have antihypertensive effects. Studies including the Optimal Macronutrient Intake to Prevent Heart Disease (OmniHeart) study, Multiple Risk Factor Intervention Trial (MRFIT), International Study of Salt and Blood Pressure (INTERSALT) and Dietary Approaches to Stop Hypertension (DASH) study have demonstrated an inverse relationship between dietary protein and blood pressure. One component of dietary protein that may partially account for its antihypertensive effect is the nonessential amino acid cysteine. Studies in hypertensive humans and animal models of hypertension have shown that N-acetylcysteine, a stable cysteine analogue, lowers blood pressure, which substantiates this idea. Cysteine may exert its antihypertensive effects directly or through its storage form, glutathione, by decreasing oxidative stress, improving insulin resistance and glucose metabolism, lowering advanced glycation end products, and modulating levels of nitric oxide and other vasoactive molecules. Therefore, adopting a balanced diet containing cysteine-rich proteins may be a beneficial lifestyle choice for individuals with hypertension. An example of such a diet is the DASH diet, which is low in salt and saturated fat; includes whole grains, poultry, fish and nuts; and is rich in vegetables, fruits and low-fat dairy products.
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Affiliation(s)
- Sudesh Vasdev
- Discipline of Medicine, Faculty of Medicine, Health Sciences Centre, Memorial University, St John's, Newfoundland
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28
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Vasdev S, Stuckless J. Antihypertensive effects of dietary protein and its mechanism. Int J Angiol 2012; 19:e7-e20. [PMID: 22477579 DOI: 10.1055/s-0031-1278362] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hypertension is a leading cause of morbidity and mortality worldwide. Individuals with hypertension are at increased risk of stroke, heart disease and kidney failure. Both genetic and lifestyle factors, particularly diet, have been attributed an important role in the development of hypertension. Reducing dietary sugar and salt intake can help lower blood pressure; similarly, adequate protein intake may also attenuate hypertension. Observational, cross-sectional and longitudinal epidemiological studies, and controlled clinical trials, have documented significant inverse associations between protein intake and blood pressure. Human and animal studies have shown that specific amino acids within proteins may have antihypertensive effects. Cysteine, glutathione (a tripeptide), glutamate and arginine attenuate and prevent alterations that cause hypertension including insulin resistance, decreased nitric oxide bioavailability, altered renin angiotensin system function, increased oxidative stress and formation of advanced glycation end products. Leucine increases protein synthesis in skeletal muscle and improves insulin resistance by modulating hepatic gluconeogenesis. Taurine and tryptophan attenuate sympathetic nervous system activity. Soy protein helps lower blood pressure through its high arginine content and antioxidant activity exhibited by isoflavones. A diet containing an ample amount of protein may be a beneficial lifestyle choice for individuals with hypertension; one example is the Dietary Approaches to Stop Hypertension (DASH) diet, which is low in salt and saturated fat; includes whole grains, lean meat, poultry, fish and nuts; and is rich in vegetables, fruits and low-fat dairy products, which are good sources of antioxidant vitamins, minerals and fibre. Including an adequate supply of soy in the diet should also be encouraged.
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Affiliation(s)
- Sudesh Vasdev
- Discipline of Medicine, Faculty of Medicine, Health Sciences Centre, Memorial University, St John's, Newfoundland and Labrador
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29
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Hyperpolarized 13C dehydroascorbate as an endogenous redox sensor for in vivo metabolic imaging. Proc Natl Acad Sci U S A 2011; 108:18606-11. [PMID: 22042839 DOI: 10.1073/pnas.1106920108] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Reduction and oxidation (redox) chemistry is involved in both normal and abnormal cellular function, in processes as diverse as circadian rhythms and neurotransmission. Intracellular redox is maintained by coupled reactions involving NADPH, glutathione (GSH), and vitamin C, as well as their corresponding oxidized counterparts. In addition to functioning as enzyme cofactors, these reducing agents have a critical role in dealing with reactive oxygen species (ROS), the toxic products of oxidative metabolism seen as culprits in aging, neurodegenerative disease, and ischemia/ reperfusion injury. Despite this strong relationship between redox and human disease, methods to interrogate a redox pair in vivo are limited. Here we report the development of [1-(13)C] dehydroascorbate [DHA], the oxidized form of Vitamin C, as an endogenous redox sensor for in vivo imaging using hyperpolarized (13)C spectroscopy. In murine models, hyperpolarized [1-(13)C] DHA was rapidly converted to [1-(13)C] vitamin C within the liver, kidneys, and brain, as well as within tumor in a transgenic prostate cancer mouse. This result is consistent with what has been previously described for the DHA/Vitamin C redox pair, and points to a role for hyperpolarized [1-(13)C] DHA in characterizing the concentrations of key intracellular reducing agents, including GSH. More broadly, these findings suggest a prognostic role for this new redox sensor in determining vulnerability of both normal and abnormal tissues to ROS.
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30
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May JM, Qu ZC, Qiao H. Transfer of ascorbic acid across the vascular endothelium: mechanism and self-regulation. Am J Physiol Cell Physiol 2009; 297:C169-78. [PMID: 19419995 DOI: 10.1152/ajpcell.00674.2008] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To determine how ascorbic acid moves from the bloodstream into tissues, we assessed transfer of the vitamin across the barrier generated by EA.hy926 endothelial cells when these were cultured on semipermeable filter supports. Ascorbate transfer from the luminal to the abluminal compartment was time dependent, inhibited by anion channel blockers and by activation of protein kinase A, but was increased by thrombin. Ascorbate transfer occurred by a paracellular route, since it did not correlate with intracellular ascorbate contents and was not rectified or saturable. Nonetheless, intracellular ascorbate inhibited the transfer of both ascorbate and radiolabeled inulin across the endothelial barrier. The increase in barrier function due to ascorbate was dependent on its intracellular concentration, significant by 15 min of incubation, prevented by the cytoskeletal inhibitor colchicine, associated with F-actin stress fiber formation, and not due to collagen deposition. These results show that ascorbate traverses the endothelial barrier by a paracellular route that is regulated by cell metabolism, ion channels, and ascorbate itself. Since the latter effect occurred over the physiological range of ascorbate plasma concentrations, it could reflect a role for the vitamin in control of endothelial barrier function in vivo.
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Affiliation(s)
- James M May
- Department of Medicine, Vanderbilt Univ. School of Medicine, Nashville, TN 37232-0475, USA.
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31
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Aguirre R, May JM. Inflammation in the vascular bed: importance of vitamin C. Pharmacol Ther 2008; 119:96-103. [PMID: 18582947 DOI: 10.1016/j.pharmthera.2008.05.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 05/09/2008] [Indexed: 02/07/2023]
Abstract
Despite decreases in atherosclerotic coronary vascular disease over the last several decades, atherosclerosis remains a major cause of mortality in developed nations. One possible contributor to this residual risk is oxidant stress, which is generated by the inflammatory response of atherosclerosis. Although there is a wealth of in vitro, cellular, and animal data supporting a protective role for antioxidant vitamins and nutrients in the atherosclerotic process, the best clinical trials have been negative. This may be due to the fact that antioxidant therapies are applied "too little and too late." This review considers the role of vitamin C, or ascorbic acid in preventing the earliest inflammatory changes in atherosclerosis. It focuses on the three major vascular cell types involved in atherosclerosis: endothelial cells, vascular smooth muscle cells, and macrophages. Ascorbate chemistry, recycling, and function are described for these cell types, with emphasis on whether and how the vitamin might affect the inflammatory process. For endothelial cells, ascorbate helps to prevent endothelial dysfunction, stimulates type IV collagen synthesis, and enhances cell proliferation. For vascular smooth muscle cells, ascorbate inhibits dedifferentiation, recruitment, and proliferation in areas of vascular damage. For macrophages, ascorbate decreases oxidant stress related to their activation, decreases uptake and degradation of oxidized LDL in some studies, and enhances several aspects of their function. Although further studies of ascorbate function in these cell types and in novel animal models are needed, available evidence generally supports a salutary role for this vitamin in ameliorating the earliest stages of atherosclerosis.
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Affiliation(s)
- Rene Aguirre
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA
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32
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Wang Y, Cloarec O, Tang H, Lindon JC, Holmes E, Kochhar S, Nicholson JK. Magic angle spinning NMR and 1H-31P heteronuclear statistical total correlation spectroscopy of intact human gut biopsies. Anal Chem 2008; 80:1058-66. [PMID: 18205334 DOI: 10.1021/ac701988a] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Previously we have demonstrated the use of 1H magic angle spinning (MAS) NMR spectroscopy for the topographical variations in functional metabolic signatures of intact human intestinal biopsy samples. Here we have analyzed a series of MAS 1H NMR spectra (spin-echo, one-dimensional, and diffusion-edited) and 31P-{1H} spectra and focused on analyzing the enhancement of information recovery by use of the statistical total correlation spectroscopy (STOCSY) method. We have applied a heterospectroscopic cross-examination performed on the same samples and between 1H and 31P-{1H} spectra (heteronuclear STOCSY) to recover latent metabolic information. We show that heterospectroscopic correlation can give new information on the molecular compartmentation of metabolites in intact tissues, including the statistical "isolation" of a phospholipid/triglyceride vesicle pool in intact tissue. The application of 31P-1H HET-STOCSY allowed the cross-assignment of major 31P signals to their equivalent 1H NMR spectra, e.g., for phosphorylcholine and phosphorylethanolamine. We also show pathway correlations, e.g., the ascorbate-glutathione pathway, in the STOCSY analysis of intact tissue spectra. These 31P-1H HET-STOCSY spectra also showed different topographical regions, particular for minor signals in different tissue microenvironments. This approach could be extended to allow the detection of altered distributions within metabolic subcompartments as well as conventional metabonomics concentration-based diagnostics.
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Affiliation(s)
- Yulan Wang
- Department of Biomolecular Medicine, SORA Division, Faculty of Medicine, Imperial College London, Sir Alexander Fleming Building, South Kensington, London, UK.
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33
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Samhan-Arias AK, Duarte RO, Martín-Romero FJ, Moura JJG, Gutiérrez-Merino C. Reduction of ascorbate free radical by the plasma membrane of synaptic terminals from rat brain. Arch Biochem Biophys 2007; 469:243-54. [PMID: 17956188 DOI: 10.1016/j.abb.2007.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 10/05/2007] [Accepted: 10/06/2007] [Indexed: 01/17/2023]
Abstract
Synaptic plasma membranes (SPMV) decrease the steady state ascorbate free radical (AFR) concentration of 1mM ascorbate in phosphate/EDTA buffer (pH 7), due to AFR recycling by redox coupling between ascorbate and the ubiquinone content of these membranes. In the presence of NADH, but not NADPH, SPMV catalyse a rapid recycling of AFR which further lower the AFR concentration below 0.05 microM. These results correlate with the nearly 10-fold higher NADH oxidase over NADPH oxidase activity of SPMV. SPMV has NADH-dependent coenzyme Q reductase activity. In the presence of ascorbate the stimulation of the NADH oxidase activity of SPMV by coenzyme Q(1) and cytochrome c can be accounted for by the increase of the AFR concentration generated by the redox pairs ascorbate/coenzyme Q(1) and ascorbate/cytochrome c. The NADH:AFR reductase activity makes a major contribution to the NADH oxidase activity of SPMV and decreases the steady-state AFR concentration well below the micromolar concentration range.
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Affiliation(s)
- Alejandro K Samhan-Arias
- Department of Biochemistry and Molecular Biology, Faculty of Sciences, University of Extremadura, 06071 Badajoz, Spain
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34
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Montecinos V, Guzmán P, Barra V, Villagrán M, Muñoz-Montesino C, Sotomayor K, Escobar E, Godoy A, Mardones L, Sotomayor P, Guzmán C, Vásquez O, Gallardo V, van Zundert B, Bono MR, Oñate SA, Bustamante M, Cárcamo JG, Rivas CI, Vera JC. Vitamin C Is an Essential Antioxidant That Enhances Survival of Oxidatively Stressed Human Vascular Endothelial Cells in the Presence of a Vast Molar Excess of Glutathione. J Biol Chem 2007; 282:15506-15. [PMID: 17403685 DOI: 10.1074/jbc.m608361200] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellular glutathione levels may exceed vitamin C levels by 10-fold, generating the question about the real antioxidant role that low intracellular concentrations of vitamin C can play in the presence of a vast molar excess of glutathione. We characterized the metabolism of vitamin C and its relationship with glutathione in primary cultures of human endothelial cells oxidatively challenged by treatment with hydrogen peroxide or with activated cells undergoing the respiratory burst, and analyzed the manner in which vitamin C interacts with glutathione to increase the antioxidant capacity of cells. Our data indicate that: (i) endothelial cells express transporters for reduced and oxidized vitamin C and accumulate ascorbic acid with participation of glutathione-dependent dehydroascorbic acid reductases, (ii) although increased intracellular levels of vitamin C or glutathione caused augmented resistance to oxidative stress, 10-times more glutathione than vitamin C was required, (iii) full antioxidant protection required the simultaneous presence of intracellular and extracellular vitamin C at concentrations normally found in vivo, and (iv) intracellular vitamin C cooperated in enhancing glutathione recovery after oxidative challenge thus providing cells with enhanced survival potential, while extracellular vitamin C was recycled through a mechanism involving the simultaneous neutralization of oxidant species. Therefore, in endothelial cells under oxidative challenge, vitamin C functions as an essential cellular antioxidant even in the presence of a vast molar excess of glutathione.
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Affiliation(s)
- Viviana Montecinos
- Departamento de Fisiopatología, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160C, Concepción, Chile
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35
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Kónya C, Ferdinandy P. Vitamin C: new role of the old vitamin in the cardiovascular system? Br J Pharmacol 2007; 147:125-7. [PMID: 16331295 PMCID: PMC1615860 DOI: 10.1038/sj.bjp.0706494] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
| | - Péter Ferdinandy
- PharmaHungary 2000 Ltd, Szeged, Hungary
- Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Dóm tér 9, Szeged, H-6720 Hungary
- Author for correspondence: www.cardiovasc.com
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36
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Merker MP, Audi SH, Bongard RD, Lindemer BJ, Krenz GS. Influence of pulmonary arterial endothelial cells on quinone redox status: effect of hyperoxia-induced NAD(P)H:quinone oxidoreductase 1. Am J Physiol Lung Cell Mol Physiol 2006; 290:L607-19. [PMID: 16243901 DOI: 10.1152/ajplung.00302.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The objective of this study was to examine the impact of chronic hyperoxic exposure (95% O2for 48 h) on intact bovine pulmonary arterial endothelial cell redox metabolism of 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ). DQ or durohydroquinone (DQH2) was added to normoxic or hyperoxia-exposed cells in air-saturated medium, and the medium DQ concentrations were measured over 30 min. DQ disappeared from the medium when DQ was added and appeared in the medium when DQH2was added, such that after ∼15 min, a steady-state DQ concentration was approached that was ∼4.5 times lower for the hyperoxia-exposed than the normoxic cells. The rate of DQ-mediated reduction of the cell membrane-impermeant redox indicator, potassium ferricyanide [Fe(CN)[Formula: see text]], was also approximately twofold faster for the hyperoxia-exposed cells. Inhibitor studies and mathematical modeling suggested that in both normoxic and hyperoxia-exposed cells, NAD(P)H:quinone oxidoreductase 1 (NQO1) was the dominant DQ reductase and mitochondrial electron transport complex III the dominant DQH2oxidase involved and that the difference between the net effects of the cells on DQ redox status could be attributed primarily to a twofold increase in the maximum NQO1-mediated DQ reduction rate in the hyperoxia-exposed cells. Accordingly, NQO1 protein and total activity were higher in hyperoxia-exposed than normoxic cell cytosolic fractions. One outcome for hyperoxia-exposed cells was enhanced protection from cell-mediated DQ redox cycling. This study demonstrates that exposure to chronic hyperoxia increases the capacity of pulmonary arterial endothelial cells to reduce DQ to DQH2via a hyperoxia-induced increase in NQO1 protein and total activity.
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Affiliation(s)
- Marilyn P Merker
- Department of Anesthesiology, Medical College of Wisconsin, VA Medical Center, Research Service 151, Milwaukee, WI 53295, USA.
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37
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Spagnuolo MS, Carlucci A, Cigliano L, Abrescia P. Nitric oxide stimulates the erythrocyte for ascorbate recycling. Nitric Oxide 2005; 14:272-7. [PMID: 16293429 DOI: 10.1016/j.niox.2005.09.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Revised: 09/06/2005] [Accepted: 09/28/2005] [Indexed: 11/30/2022]
Abstract
S-Nitrosothiols act as carrier and reservoir of nitric oxide (NO), and release NO under stimulation of ascorbate (Asc). Erythrocyte can regenerate Asc from its oxidised products, thus saving this powerful antioxidant. In this paper the effect of donors of NO, superoxide, and peroxynitrite (SpNONOate, KO(2), and SIN-1, respectively) on the erythrocyte production of Asc was investigated. We report here that NO stimulated, while superoxide and peroxynitrite decreased, the Asc recycling. The NO-stimulating effect on the erythrocyte production of Asc was confirmed by using GSNO, a natural occurring S-nitrosothiol, as NO donor. These data highlight a new property of NO, that is the stimulation of erythrocytes for their Asc recycling. Such a property might contribute to regenerate Asc from its oxidised forms, thus preventing its depletion in the circulation. Temperature and pH significantly affected, both in absence and presence of NO, the recycling of Asc by erythrocytes. We propose that a positive feedback, involving the reciprocal stimulation between Asc and S-nitrosothiols, might enhance productions of Asc by erythrocytes and NO release by circulating S-nitrosothiols.
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Affiliation(s)
- Maria Stefania Spagnuolo
- Dipartimento delle Scienze Biologiche, Università di Napoli Federico II, via Mezzocannone 8, 80134 Napoli, Italy
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Buehler PW, Alayash AI. Redox biology of blood revisited: the role of red blood cells in maintaining circulatory reductive capacity. Antioxid Redox Signal 2005; 7:1755-60. [PMID: 16356136 DOI: 10.1089/ars.2005.7.1755] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
There is an increasing recognition of the role of red blood cells (RBCs) in cell signaling above and beyond its oxygen (O(2))-carrying function. A recent forum published in the December 2004 issue of Antioxidants & Redox Signaling focused on redox biology of blood and the intricate signaling pathways of RBCs or its free components, i.e., hemoglobin, with the vasculature. The forum provided an up-to-date source of information on this emerging and exciting area of blood biology and the underlying redox chemistry. In the current short review, we have revisited the topic of redox biology of blood and focused on yet another emerging area of research, which deals with the reductive power of blood and the physiological Redox Signal.
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Affiliation(s)
- Paul W Buehler
- Laboratory of Biochemistry and Vascular Biology, Division of Hematology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA
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Dhar-Mascareño M, Cárcamo JM, Golde DW. Hypoxia-reoxygenation-induced mitochondrial damage and apoptosis in human endothelial cells are inhibited by vitamin C. Free Radic Biol Med 2005; 38:1311-22. [PMID: 15855049 DOI: 10.1016/j.freeradbiomed.2005.01.017] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Revised: 01/20/2005] [Accepted: 01/20/2005] [Indexed: 10/25/2022]
Abstract
Hypoxia and hypoxia-reperfusion (H-R) play important roles in human pathophysiology because they occur in clinical conditions such as circulatory shock, myocardial ischemia, stroke, and organ transplantation. Reintroduction of oxygen to hypoxic cells during reperfusion causes an increase in generation of reactive oxygen species (ROS), which can alter cell signaling, and cause damage to lipids, proteins, and DNA leading to ischemia-reperfusion injury. Since vitamin C is a potent antioxidant and quenches ROS, we investigated the role of intracellular ascorbic acid (iAA) in endothelial cells undergoing hypoxia-reperfusion. Intracellular AA protected human endothelial cells from H-R-induced apoptosis. Intracellular AA also prevents loss of mitochondrial membrane potential and the release of cytochrome C and activation of caspase-9 and caspase-3 during H-R. Additionally, inhibition of caspase-9 activation prevented H-R-induced apoptosis, suggesting a mitochondrial site of initiation of apoptosis. We found that H-R induced an increase in ROS in endothelial cells that was abrogated in the presence of iAA. Our results indicate that vitamin C prevents hypoxia and H-R-induced damage to human endothelium.
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Affiliation(s)
- Manya Dhar-Mascareño
- Molecular Pharmacology and Chemistry Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
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May JM, Qu ZC. Nitric oxide-induced oxidant stress in endothelial cells: amelioration by ascorbic acid. Arch Biochem Biophys 2004; 429:106-13. [PMID: 15288814 DOI: 10.1016/j.abb.2004.06.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Revised: 06/11/2004] [Indexed: 10/26/2022]
Abstract
Nitric oxide has multiple beneficial effects in the blood vessel wall. However, high concentrations of nitric oxide in the presence of hydroperoxides have been shown to damage cultured cells. In this work, the effect of relatively high concentrations of nitric oxide alone on the function and antioxidant status of a human endothelial cell line (EA.hy926) was tested. Nitric oxide generated from 0.1 to 0.5mM spermine NONOate generated reactive species in the cells detected by triazole formation from diaminofluorescein and by oxidation of dihydrofluorescein. Intracellular ascorbic acid decreased this oxidant stress. Spermine NONOate also decreased intracellular ascorbate concentrations, although reduced glutathione was not affected unless cells had also been caused to reduce dehydroascorbic acid to ascorbate. Nitric oxide predictably inhibited both endothelial nitric oxide synthase and glyceraldehyde 3-phosphate dehydrogenase, and ascorbate partially prevented inhibition of the latter enzyme. These results suggest that relatively high concentrations of nitric oxide can cause oxidant stress in endothelial cells that is ameliorated by ascorbic acid.
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Affiliation(s)
- James M May
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-6303, USA.
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Merker MP, Bongard RD, Krenz GS, Zhao H, Fernandes VS, Kalyanaraman B, Hogg N, Audi SH. Impact of pulmonary arterial endothelial cells on duroquinone redox status. Free Radic Biol Med 2004; 37:86-103. [PMID: 15183197 DOI: 10.1016/j.freeradbiomed.2004.02.078] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Revised: 02/13/2004] [Accepted: 02/27/2004] [Indexed: 10/26/2022]
Abstract
The study objective was to use pulmonary arterial endothelial cells to examine kinetics and mechanisms contributing to the disposition of the quinone 2,3,5,6-tetramethyl-1,4-benzoquinone (duroquinone, DQ) observed during passage through the pulmonary circulation. The approach was to add DQ, durohydroquinone (DQH2), or DQ with the cell membrane-impermeant oxidizing agent, ferricyanide (Fe(CN)6(3)-), to the cell medium, and to measure the medium concentrations of substrates and products over time. Studies were carried out under control conditions and with dicumarol, to inhibit NAD(P)H:quinone oxidoreductase 1 (NQO1), or cyanide, to inhibit mitochondrial electron transport. In control cells, DQH2 appears in the extracellular medium of cells incubated with DQ, and DQ appears when the cells are incubated with DQH2. Dicumarol blocked the appearance of DQH2 when DQ was added to the cell medium, and cyanide blocked the appearance of DQ when DQH2 was added to the cell medium, suggesting that the two electron reductase NQO1 dominates DQ reduction and mitochondrial electron transport complex III is the predominant route of DQH2 oxidation. In the presence of cyanide, the addition of DQ also resulted in an increased rate of appearance of DQH2 and stimulation of cyanide-insensitive oxygen consumption. As DQH2 does not autoxidize-comproportionate over the study time course, these observations suggest a cyanide-stimulated one-electron DQ reduction and durosemiquinone (DQ*-) autoxidation. The latter processes are apparently confined to the cell interior, as the cell membrane impermeant oxidant, ferricyanide, did not inhibit the DQ-stimulated cyanide-insensitive oxygen consumption. Thus, regardless of whether DQ is reduced via a one- or two-electron reduction pathway, the net effect in the extracellular medium is the appearance of DQH2. These endothelial redox functions and their apposition to the vessel lumen are consistent with the pulmonary endothelium being an important site of DQ reduction to DQH2 observed in the lungs.
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Affiliation(s)
- Marilyn P Merker
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, USA.
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