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Huang J, Qiu Y, Lücke F, Su J, Grundmeier G, Keller A. Multiprotein Adsorption from Human Serum at Gold and Oxidized Iron Surfaces Studied by Atomic Force Microscopy and Polarization-Modulation Infrared Reflection Absorption Spectroscopy. Molecules 2023; 28:6060. [PMID: 37630312 PMCID: PMC10459451 DOI: 10.3390/molecules28166060] [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: 07/20/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 08/27/2023] Open
Abstract
Multiprotein adsorption from complex body fluids represents a highly important and complicated phenomenon in medicine. In this work, multiprotein adsorption from diluted human serum at gold and oxidized iron surfaces is investigated at different serum concentrations and pH values. Adsorption-induced changes in surface topography and the total amount of adsorbed proteins are quantified by atomic force microscopy (AFM) and polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS), respectively. For both surfaces, stronger protein adsorption is observed at pH 6 compared to pH 7 and pH 8. PM-IRRAS furthermore provides some qualitative insights into the pH-dependent alterations in the composition of the adsorbed multiprotein films. Changes in the amide II/amide I band area ratio and in particular side-chain IR absorption suggest that the increased adsorption at pH 6 is accompanied by a change in protein film composition. Presumably, this is mostly driven by the adsorption of human serum albumin, which at pH 6 adsorbs more readily and thereby replaces other proteins with lower surface affinities in the resulting multiprotein film.
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Affiliation(s)
| | | | | | | | | | - Adrian Keller
- Technical and Macromolecular Chemistry, Paderborn University, Warburger Str. 100, 33098 Paderborn, Germany; (J.H.); (Y.Q.); (F.L.); (J.S.); (G.G.)
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2
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Zhang KR, Jankowski CSR, Marshall R, Nair R, Más Gómez N, Alnemri A, Liu Y, Erler E, Ferrante J, Song Y, Bell BA, Baumann BH, Sterling J, Anderson B, Foshe S, Roof J, Fazelinia H, Spruce LA, Chuang JZ, Sung CH, Dhingra A, Boesze-Battaglia K, Chavali VRM, Rabinowitz JD, Mitchell CH, Dunaief JL. Oxidative stress induces lysosomal membrane permeabilization and ceramide accumulation in retinal pigment epithelial cells. Dis Model Mech 2023; 16:dmm050066. [PMID: 37401371 PMCID: PMC10399446 DOI: 10.1242/dmm.050066] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/23/2023] [Indexed: 07/05/2023] Open
Abstract
Oxidative stress has been implicated in the pathogenesis of age-related macular degeneration, the leading cause of blindness in older adults, with retinal pigment epithelium (RPE) cells playing a key role. To better understand the cytotoxic mechanisms underlying oxidative stress, we used cell culture and mouse models of iron overload, as iron can catalyze reactive oxygen species formation in the RPE. Iron-loading of cultured induced pluripotent stem cell-derived RPE cells increased lysosomal abundance, impaired proteolysis and reduced the activity of a subset of lysosomal enzymes, including lysosomal acid lipase (LIPA) and acid sphingomyelinase (SMPD1). In a liver-specific Hepc (Hamp) knockout murine model of systemic iron overload, RPE cells accumulated lipid peroxidation adducts and lysosomes, developed progressive hypertrophy and underwent cell death. Proteomic and lipidomic analyses revealed accumulation of lysosomal proteins, ceramide biosynthetic enzymes and ceramides. The proteolytic enzyme cathepsin D (CTSD) had impaired maturation. A large proportion of lysosomes were galectin-3 (Lgals3) positive, suggesting cytotoxic lysosomal membrane permeabilization. Collectively, these results demonstrate that iron overload induces lysosomal accumulation and impairs lysosomal function, likely due to iron-induced lipid peroxides that can inhibit lysosomal enzymes.
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Affiliation(s)
- Kevin R. Zhang
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Connor S. R. Jankowski
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Rayna Marshall
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Rohini Nair
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Néstor Más Gómez
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ahab Alnemri
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yingrui Liu
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elizabeth Erler
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Julia Ferrante
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ying Song
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brent A. Bell
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bailey H. Baumann
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jacob Sterling
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Brandon Anderson
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sierra Foshe
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jennifer Roof
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Hossein Fazelinia
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Lynn A. Spruce
- CHOP-PENN Proteomics Core Facility, The Children's Hospital of Philadelphia Research Institute, Philadelphia, PA 19104, USA
| | - Jen-Zen Chuang
- Department of Ophthalmology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Ching-Hwa Sung
- Department of Ophthalmology, Weill Cornell Medicine, New York, NY 10065, USA
- Department of Cell and Developmental Biology, Weill Cornell Medicine, New York, NY 10065, USA
| | - Anuradha Dhingra
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kathleen Boesze-Battaglia
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Venkata R. M. Chavali
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua D. Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Claire H. Mitchell
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joshua L. Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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Dasagrandhi D, Muthuswamy A, Swaminathan JK. Atherosclerosis: nexus of vascular dynamics and cellular cross talks. Mol Cell Biochem 2022; 477:571-584. [PMID: 34845570 DOI: 10.1007/s11010-021-04307-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/17/2021] [Indexed: 01/11/2023]
Abstract
Cardiovascular diseases (CVDs) are the foremost cause of mortality worldwide. Atherosclerosis is the underlying pathology behind CVDs. Atherosclerosis is manifested predominantly by lipid deposition, plaque formation, and inflammation in vascular intima. Initiation and progression of plaque require many years. With aging, atherosclerotic plaques become vulnerable. Localization of these plaques in the coronary artery leads to myocardial infarction. A complete understanding of the pathophysiology of this multifaceted disease is necessary to achieve the clinical goal to provide early diagnosis and the best therapeutics. The triggering factors of atherosclerosis are biomechanical forces, hyperlipidemia, and chronic inflammatory response. The current review focuses on crucial determinants involved in the disease, such as location, hemodynamic factors, oxidation of low-density lipoproteins, and the role of endothelial cells, vascular smooth muscle cells, and immune cells, and better therapeutic targets.
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Affiliation(s)
- Divya Dasagrandhi
- Drug Discovery and Molecular Cardiology Laboratory, Department of Bioinformatics, Bharathidasan University, Tiruchirappalli, 620024, India
| | - Anusuyadevi Muthuswamy
- Molecular Neurogerontology Laboratory, Department of Biochemistry, Bharathidasan University, Tiruchirappalli, 620024, India
| | - Jayachandran Kesavan Swaminathan
- Drug Discovery and Molecular Cardiology Laboratory, Department of Bioinformatics, Bharathidasan University, Tiruchirappalli, 620024, India.
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Wang J, Xue T, Li H, Guo S. Nomogram Prediction for the Risk of Diabetic Foot in Patients With Type 2 Diabetes Mellitus. Front Endocrinol (Lausanne) 2022; 13:890057. [PMID: 35909507 PMCID: PMC9325991 DOI: 10.3389/fendo.2022.890057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 06/13/2022] [Indexed: 11/29/2022] Open
Abstract
AIMS To develop and validate a nomogram prediction model for the risk of diabetic foot in patients with type 2 diabetes mellitus (T2DM) and evaluate its clinical application value. METHODS We retrospectively collected clinical data from 1,950 patients with T2DM from the Second Affiliated Hospital of Xi'an Jiaotong University between January 2012 and June 2021. The patients were divided into training cohort and validation cohort according to the random number table method at a ratio of 7:3. The independent risk factors for diabetic foot among patients with T2DM were identified by multivariate logistic regression analysis. Then, a nomogram prediction model was developed using the independent risk factors. The model performances were evaluated by the area under the receiver operating characteristic curve (AUC), calibration plot, Hosmer-Lemeshow test, and the decision curve analysis (DCA). RESULTS Multivariate logistic regression analysis indicated that age, hemoglobin A1c (HbA1c), low-density lipoprotein (LDL), total cholesterol (TC), smoke, and drink were independent risk factors for diabetic foot among patients with T2DM (P < 0.05). The AUCs of training cohort and validation cohort were 0.806 (95% CI: 0.775∼0.837) and 0.857 (95% CI: 0.814∼0.899), respectively, suggesting good discrimination of the model. Calibration curves of training cohort and validation cohort showed a favorable consistency between the predicted probability and the actual probability. In addition, the P values of Hosmer-Lemeshow test for training cohort and validation cohort were 0.826 and 0.480, respectively, suggesting a high calibration of the model. When the threshold probability was set as 11.6% in the DCA curve, the clinical net benefits of training cohort and validation cohort were 58% and 65%, respectively, indicating good clinical usefulness of the model. CONCLUSION We developed and validated a user-friendly nomogram prediction model for the risk of diabetic foot in patients with T2DM. Nomograms may help clinicians early screen and identify patients at high risk of diabetic foot.
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Affiliation(s)
- Jie Wang
- Department of Orthopedic Surgery, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Tong Xue
- Department of Neonatology, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
| | - Haopeng Li
- Department of Orthopedic Surgery, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
- *Correspondence: Haopeng Li,
| | - Shuai Guo
- Department of Orthopedic Surgery, Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, China
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Ojo OO, Leake DS. Vitamins E and C do not effectively inhibit low density lipoprotein oxidation by ferritin at lysosomal pH. Free Radic Res 2021; 55:525-534. [PMID: 34396869 DOI: 10.1080/10715762.2021.1964494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Low density lipoprotein (LDL) might be oxidized by iron in the lysosomes of macrophages in atherosclerotic lesions. We have shown previously that the iron-storage proteinferritin can oxidize LDL at lysosomal pH. We have now investigated the roles of the most important antioxidant contained in LDL, α-tocopherol (the main form of vitamin E) and of ascorbate (vitamin C), a major water-soluble antioxidant, on LDL oxidation by ferritin at lysosomal pH (pH 4.5). We incubated LDL with ferritin at pH 4.5 and 37 °C and measured its oxidation by monitoring the formation of conjugated dienes at 234 n min a spectrophotometer. α-Tocopherol is well known to inhibit LDL oxidation at pH 7.4, but enrichment of LDL with α-tocopherol was unable to inhibit LDL oxidation by ferritin at pH 4.5. Ascorbate had a complex effect on LDL oxidation by ferritin at lysosomal pH and exhibited both antioxidant and pro-oxidant effects. It had no antioxidant effect on partially oxidized LDL, only a pro-oxidant effect. Ascorbate completely inhibited LDL oxidation by copper at pH 7.4 for a long period, but in marked contrast did not inhibit LDL oxidation by copper at lysosomal pH. Dehydroascorbate, the oxidation product of ascorbate, had a pronounced pro-oxidant effect on LDL incubated with ferritin at pH 4.5. The inability of α-tocopherol and ascorbate to effectively inhibit LDL oxidation by ferritin at lysosomal pH might help to explain why the large clinical trials with these vitamins failed to show protection against cardiovascular diseases.
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Affiliation(s)
- Oluwatosin O Ojo
- School of Biological Sciences and Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, Berkshire, UK
| | - David S Leake
- School of Biological Sciences and Institute for Cardiovascular and Metabolic Research, University of Reading, Reading, Berkshire, UK
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Amar Z, Talpur AS, Zafar S, Memon A, Nazary K, Esmati S, Hashim S, Maqsood H, Hafizyar F, Kumar B. Comparison of Iron Profile in Patients With and Without Coronary Heart Disease. Cureus 2021; 13:e15613. [PMID: 34277231 PMCID: PMC8275058 DOI: 10.7759/cureus.15613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/11/2021] [Indexed: 11/05/2022] Open
Abstract
Introduction Atherosclerosis is considered a major cause of coronary artery disease (CAD). Pathogenesis of atherosclerosis involves the oxidation of low-density lipoprotein (LDL) within the lysosomes of macrophages. Ferritin and iron have pro-oxidant properties, and ferritin is an independent positive determinant of oxidized LDL level. In this study, we will determine the association between ferritin and serum iron levels and CAD. Methods This case-control study was conducted in the cardiology unit of a tertiary care hospital in Pakistan from December 2020 to April 2021. After taking informed consent, 400 patients with a confirmed diagnosis of CAD were enrolled. Another set of 400 patients without a history of CAD were included in the control group. A blood sample of 5 ml was drawn and sent to the laboratory to test for ferritin, serum iron, and total iron-binding capacity (TIBC). Ferritin, serum iron, and iron-binding capacity were compared between the case and control groups. Results Serum ferritin was significantly higher in patients with CAD compared to patients without CAD (921.21 ± 201.21 ug/L vs. 101.21 ± 92.21 ug/L; p-value: <0.0001). Serum TIBC was significantly lower in patients with CAD compared to patients without CAD (302.12 ± 101.75 umol/L vs. 362.12 ± 82.16 umol/L). Conclusion Patients with raised levels of ferritin should consult a physician to manage their ferritin levels since they are at a greater risk of CAD. Treatment ranges from lifestyle changes to pharmacological therapy, thus reducing the overall risk and normalizing the ferritin levels.
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Affiliation(s)
- Zain Amar
- Internal Medicine, Isra University, Hyderabad, PAK
| | - Abdul Subhan Talpur
- Internal Medicine, Liaquat University of Medical and Health Sciences, Jamshoro, PAK
| | | | | | | | - Saliman Esmati
- Internal Medicine, Jamaica Hospital Medical Center, New York City, USA
| | - Sara Hashim
- Pathology and Laboratory Medicine, Bolan Medical College, Quetta, PAK
| | - Hamza Maqsood
- Internal Medicine, Nishtar Medical University, Multan, PAK
| | | | - Besham Kumar
- Internal Medicine, Jinnah Postgraduate Medical Centre, Karachi, PAK
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Marques ARA, Ramos C, Machado-Oliveira G, Vieira OV. Lysosome (Dys)function in Atherosclerosis-A Big Weight on the Shoulders of a Small Organelle. Front Cell Dev Biol 2021; 9:658995. [PMID: 33855029 PMCID: PMC8039146 DOI: 10.3389/fcell.2021.658995] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/11/2021] [Indexed: 12/15/2022] Open
Abstract
Atherosclerosis is a progressive insidious chronic disease that underlies most of the cardiovascular pathologies, including myocardial infarction and ischemic stroke. The malfunctioning of the lysosomal compartment has a central role in the etiology and pathogenesis of atherosclerosis. Lysosomes are the degradative organelles of mammalian cells and process endogenous and exogenous substrates in a very efficient manner. Dysfunction of these organelles and consequent inefficient degradation of modified low-density lipoproteins (LDL) and apoptotic cells in atherosclerotic lesions have, therefore, numerous deleterious consequences for cellular homeostasis and disease progression. Lysosome dysfunction has been mostly studied in the context of the inherited lysosomal storage disorders (LSDs). However, over the last years it has become increasingly evident that the consequences of this phenomenon are more far-reaching, also influencing the progression of multiple acquired human pathologies, such as neurodegenerative diseases, cancer, and cardiovascular diseases (CVDs). During the formation of atherosclerotic plaques, the lysosomal compartment of the various cells constituting the arterial wall is under severe stress, due to the tremendous amounts of lipoproteins being processed by these cells. The uncontrolled uptake of modified lipoproteins by arterial phagocytic cells, namely macrophages and vascular smooth muscle cells (VSMCs), is the initial step that triggers the pathogenic cascade culminating in the formation of atheroma. These cells become pathogenic "foam cells," which are characterized by dysfunctional lipid-laden lysosomes. Here, we summarize the current knowledge regarding the origin and impact of the malfunctioning of the lysosomal compartment in plaque cells. We further analyze how the field of LSD research may contribute with some insights to the study of CVDs, particularly how therapeutic approaches that target the lysosomes in LSDs could be applied to hamper atherosclerosis progression and associated mortality.
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Affiliation(s)
- André R A Marques
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Cristiano Ramos
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Gisela Machado-Oliveira
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Otília V Vieira
- iNOVA4Health, Chronic Diseases Research Center (CEDOC), NOVA Medical School (NMS), Universidade NOVA de Lisboa, Lisbon, Portugal
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Alboaklah HKM, Leake DS. Effect of vitamin E on low density lipoprotein oxidation at lysosomal pH. Free Radic Res 2020; 54:574-584. [PMID: 32938237 DOI: 10.1080/10715762.2020.1817912] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Many cholesterol-laden foam cells in atherosclerotic lesions are macrophages and much of their cholesterol is present in their lysosomes and derived from low density lipoprotein (LDL). LDL oxidation has been proposed to be involved in the pathogenesis of atherosclerosis. We have shown previously that LDL can be oxidised in the lysosomes of macrophages. α-Tocopherol has been shown to inhibit LDL oxidation in vitro, but did not protect against cardiovascular disease in large clinical trials. We have therefore investigated the effect of α-tocopherol on LDL oxidation at lysosomal pH (about pH 4.5). LDL was enriched with α-tocopherol by incubating human plasma with α-tocopherol followed by LDL isolation by ultracentrifugation. The α-tocopherol content of LDL was increased from 14.4 ± 0.2 to 24.3 ± 0.3 nmol/mg protein. LDL oxidation was assessed by measuring the formation of conjugated dienes at 234 nm and oxidised lipids (cholesteryl linoleate hydroperoxide and 7-ketocholesterol) by HPLC. As expected, LDL enriched with α-tocopherol was oxidised more slowly than control LDL by Cu2+ at pH 7.4, but was not protected against oxidation by Cu2+ or Fe3+ or a low concentration of Fe2+ at pH 4.5 (it was sometimes oxidised faster by α-tocopherol with Cu2+ or Fe3+ at pH 4.5). α-Tocopherol-enriched LDL reduced Cu2+ and Fe3+ into the more pro-oxidant Cu+ and Fe2+ faster than did control LDL at pH 4.5. These findings might help to explain why the large clinical trials of α-tocopherol did not protect against cardiovascular disease.
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Affiliation(s)
- Hadeel K M Alboaklah
- School of Biological Sciences and Institute of Cardiovascular and Metabolic Research, Hopkins Building, University of Reading, Reading, UK.,Pharmacy College, University of Karbala, Karbala, Iraq
| | - David S Leake
- School of Biological Sciences and Institute of Cardiovascular and Metabolic Research, Hopkins Building, University of Reading, Reading, UK
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Lapenna D, Ciofani G. Chromium and human low-density lipoprotein oxidation. J Trace Elem Med Biol 2020; 59:126411. [PMID: 32058272 DOI: 10.1016/j.jtemb.2019.126411] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 09/16/2019] [Accepted: 09/23/2019] [Indexed: 11/16/2022]
Abstract
Chromium is a catalytic metal able to foster oxidant damage, albeit its capacity to induce human LDL oxidation is to date unkown. Thus, we have investigated whether trivalent and hexavalent chromium, namely Cr(III) and Cr(VI), can induce human LDL oxidation. Cr(III) as CrCl3 is incapable of inducing LDL oxidation at pH 7.4 or 4.5. However, Cr(III), specifically at physiological pH of 7.4 and in the presence of phosphates, causes an absorbance increase at 234 resembling a spectrophotometric kinetics of LDL oxidation with a lag- and propagation-like phase. In this regard, it is conceivable that peculiar Cr(III) forms such as Cr(III) hydroxide and, especially, Cr(III) polynuclear hydroxocomplexes formed at pH 7.4 interact with phosphates generating species with an intrinsic absorbance at 234 nm, which increases over time resembling a spectrophotometric kinetics of LDL oxidation. Cr(VI), as K2Cr2O7, can instead induce substantial human LDL oxidation at acidic pH such as 4.5, which is typical of the intracellular lysosomal compartment. LDL oxidation is related to binding of Cr(VI) to LDL particles with quenching of the LDL tryptophan fluorescence, and it is inhibited by the metal chelators EDTA and deferoxamine, as well as by the chain-breaking antioxidants butylated hydroxytoluene and probucol. Moreover, Cr(VI)-induced LDL oxidation is inhibited by mannitol conceivably by binding Cr(V) formed from LDL-dependent Cr(VI) reduction and not by scavenging hydroxyl radicals (OH); indeed, the OH scavengers sodium formate and ethanol are ineffective against Cr(VI)-induced LDL oxidation. Notably, heightened LDL lipid hydroperoxide levels and decreased LDL tryptophan fluorescence occur in Cr plating workers, indicating Cr-induced human LDL oxidation in vivo. The biochemical, pathophysiological and clinical implications of these novel findings on chromium and human LDL oxidation are discussed.
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Affiliation(s)
- Domenico Lapenna
- Dipartimento di Medicina e Scienze dell'Invecchiamento, and Laboratorio di Fisiopatologia dello Stress Ossidativo, Center for Advanced Studies and Technology (CAST, former CeSI-Met, Center of Excellence on Aging), Università degli Studi "G. D'Annunzio" Chieti-Pescara, 66100, Chieti, Italy.
| | - Giuliano Ciofani
- Dipartimento di Medicina e Scienze dell'Invecchiamento, and Laboratorio di Fisiopatologia dello Stress Ossidativo, Center for Advanced Studies and Technology (CAST, former CeSI-Met, Center of Excellence on Aging), Università degli Studi "G. D'Annunzio" Chieti-Pescara, 66100, Chieti, Italy
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Schaefer EL, Zopyrus N, Zielinski ZAM, Facey GA, Pratt DA. On the Products of Cholesterol Autoxidation in Phospholipid Bilayers and the Formation of Secosterols Derived Therefrom. Angew Chem Int Ed Engl 2020; 59:2089-2094. [DOI: 10.1002/anie.201914637] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Emily L. Schaefer
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Nadia Zopyrus
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Zosia A. M. Zielinski
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Glenn A. Facey
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Derek A. Pratt
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
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11
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Schaefer EL, Zopyrus N, Zielinski ZAM, Facey GA, Pratt DA. On the Products of Cholesterol Autoxidation in Phospholipid Bilayers and the Formation of Secosterols Derived Therefrom. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201914637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Emily L. Schaefer
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Nadia Zopyrus
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Zosia A. M. Zielinski
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Glenn A. Facey
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
| | - Derek A. Pratt
- Department of Chemistry and Biomolecular SciencesUniversity of Ottawa 10 Marie Cure Pvt. Ottawa Ontario K1N 6N5 Canada
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12
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Cysteamine inhibits lysosomal oxidation of low density lipoprotein in human macrophages and reduces atherosclerosis in mice. Atherosclerosis 2019; 291:9-18. [PMID: 31629988 PMCID: PMC6912160 DOI: 10.1016/j.atherosclerosis.2019.09.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 09/18/2019] [Accepted: 09/25/2019] [Indexed: 12/22/2022]
Abstract
Background and aims We have shown previously that low density lipoprotein (LDL) aggregated by vortexing is internalised by macrophages and oxidised by iron in lysosomes to form the advanced lipid/protein oxidation product ceroid. We have now used sphingomyelinase-aggregated LDL, a more pathophysiological form of aggregated LDL, to study lysosomal oxidation of LDL and its inhibition by antioxidants, including cysteamine (2-aminoethanethiol), which concentrates in lysosomes by several orders of magnitude. We have also investigated the effect of cysteamine on atherosclerosis in mice. Methods LDL was incubated with sphingomyelinase, which increased its average particle diameter from 26 to 170 nm, and was then incubated for up to 7 days with human monocyte-derived macrophages. LDL receptor-deficient mice were fed a Western diet (19–22 per group) and some given cysteamine in their drinking water at a dose equivalent to that used in cystinosis patients. The extent of atherosclerosis in the aortic root and the rest of the aorta was measured. Results Confocal microscopy revealed lipid accumulation in lysosomes in the cultured macrophages. Large amounts of ceroid were produced, which colocalised with the lysosomal marker LAMP2. The antioxidants cysteamine, butylated hydroxytoluene, amifostine and its active metabolite WR-1065, inhibited the production of ceroid. Cysteamine at concentrations well below those expected to be present in lysosomes inhibited the oxidation of LDL by iron ions at lysosomal pH (pH 4.5) for prolonged periods. Finally, we showed that the extent of atherosclerotic lesions in the aortic root and arch of mice was significantly reduced by cysteamine. Conclusions These results support our hypothesis that lysosomal oxidation of LDL is important in atherosclerosis and hence antioxidant drugs that concentrate in lysosomes might provide a novel therapy for this disease. The drug cysteamine, which accumulates in lysosomes, inhibited the oxidation of LDL by iron at pH 4.5 (the pH of lysosomes). Cysteamine inhibited the lysosomal oxidation of LDL inside cultured macrophages. Cysteamine reduced atherosclerosis in LDL receptor knockout mice. These results support our hypothesis that lysosomal oxidation of LDL is important in atherosclerosis. Antioxidant drugs that concentrate in lysosomes might provide a novel therapy for this disease.
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Grammer TB, Scharnagl H, Dressel A, Kleber ME, Silbernagel G, Pilz S, Tomaschitz A, Koenig W, Mueller-Myhsok B, März W, Strnad P. Iron Metabolism, Hepcidin, and Mortality (the Ludwigshafen Risk and Cardiovascular Health Study). Clin Chem 2019; 65:849-861. [PMID: 30917972 DOI: 10.1373/clinchem.2018.297242] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 02/21/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Anemia has been shown to be a risk factor for coronary artery disease (CAD) and mortality, whereas the role of iron metabolism remains controversial. METHODS We analyzed iron metabolism and its associations with cardiovascular death and total mortality in patients undergoing coronary angiography with a median follow-up of 9.9 years. Hemoglobin and iron status were determined in 1480 patients with stable CAD and in 682 individuals in whom significant CAD had been excluded by angiography. RESULTS Multivariate-adjusted hazard ratios (HRs) for total mortality in the lowest quartiles of iron, transferrin saturation, ferritin, soluble transferrin receptor (sTfR), and hemoglobin were 1.22 (95% CI, 0.96-1.60), 1.23 (95% CI, 0.97-1.56), 1.27 (95% CI, 1.02-1.58), 1.26 (95% CI, 0.97-1.65), and 0.99 (95% CI, 0.79-1.24), respectively, compared to the second or third quartile, which served as reference (1.00) because of a J-shaped association. The corresponding HRs for total mortality in the highest quartiles were 1.44 (95% CI, 1.10-1.87), 1.37 (95% CI, 1.05-1.77), 1.17 (95% CI, 0.92-1.50), 1.76 (95% CI, 1.39-2.22), and 0.83 (95% CI, 0.63-1.09). HRs for cardiovascular death were similar. For hepcidin, the adjusted HRs for total mortality and cardiovascular deaths were 0.62 (95% CI, 0.49-0.78) and 0.70 (95% CI, 0.52-0.90) in the highest quartile compared to the lowest one. CONCLUSIONS In stable patients undergoing angiography, serum iron, transferrin saturation, sTfR, and ferritin had J-shaped associations and hemoglobin only a marginal association with cardiovascular and total mortality. Hepcidin was continuously and inversely related to mortality.
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Affiliation(s)
- Tanja B Grammer
- Mannheim Institute of Public Health, Social and Preventive Medicine, Mannheim Medical Faculty, University of Heidelberg, Mannheim, Germany; .,Department of Internal Medicine V (Nephrology, Hypertensiology, Endocrinology, Diabetolgy, and Rheumatology), Mannheim Medical Faculty, University of Heidelberg, Mannheim, Germany
| | - Hubert Scharnagl
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Alexander Dressel
- DACH Society for the Prevention of Cardiovascular Diseases, Hamburg, Germany
| | - Marcus E Kleber
- Department of Internal Medicine V (Nephrology, Hypertensiology, Endocrinology, Diabetolgy, and Rheumatology), Mannheim Medical Faculty, University of Heidelberg, Mannheim, Germany
| | - Günther Silbernagel
- Division of Angiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.,Department of Cardiology, Charité Berlin, Berlin Institute of Health and German Research Centre for Cardiovascular Research, Berlin, Germany
| | - Stefan Pilz
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | | | - Wolfgang Koenig
- Deutsches Herzzentrum München, Technische Universität München, Munich, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Bertram Mueller-Myhsok
- Max Planck Institute of Psychiatry, Munich, Germany.,Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.,Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Winfried März
- Department of Internal Medicine V (Nephrology, Hypertensiology, Endocrinology, Diabetolgy, and Rheumatology), Mannheim Medical Faculty, University of Heidelberg, Mannheim, Germany.,Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria.,Synlab Academy, Synlab Holding Deutschland GmbH, Augsburg and Mannheim, Germany
| | - Pavel Strnad
- Department of Internal Medicine III and IZKF, University Hospital Aaachen, Aachen, Germany
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14
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Low density lipoprotein oxidation by ferritin at lysosomal pH. Chem Phys Lipids 2018; 217:51-57. [DOI: 10.1016/j.chemphyslip.2018.09.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/05/2018] [Accepted: 09/29/2018] [Indexed: 01/19/2023]
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15
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Ahmad F, Leake DS. Lysosomal oxidation of LDL alters lysosomal pH, induces senescence, and increases secretion of pro-inflammatory cytokines in human macrophages. J Lipid Res 2018; 60:98-110. [PMID: 30397186 PMCID: PMC6314264 DOI: 10.1194/jlr.m088245] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/29/2018] [Indexed: 12/22/2022] Open
Abstract
We have shown that aggregated LDL is internalized by macrophages and oxidized in lysosomes by redox-active iron. We have now investigated to determine whether the lysosomal oxidation of LDL impairs lysosomal function and whether a lysosomotropic antioxidant can prevent these alterations. LDL aggregated by SMase (SMase-LDL) caused increased lysosomal lipid peroxidation in human monocyte-derived macrophages or THP-1 macrophage-like cells, as shown by a fluorescent probe, Foam-LPO. The pH of the lysosomes was increased considerably by lysosomal LDL oxidation as shown by LysoSensor Yellow/Blue and LysoTracker Red. SMase-LDL induced senescence-like properties in the cells as shown by β-galactosidase staining and levels of p53 and p21. Inflammation plays a key role in atherosclerosis. SMase-LDL treatment increased the lipopolysaccharide-induced secretion of TNF-α, IL-6, and MCP-1. The lysosomotropic antioxidant, cysteamine, inhibited all of the above changes. Targeting lysosomes with antioxidants, such as cysteamine, to prevent the intralysosomal oxidation of LDL might be a novel therapy for atherosclerosis.
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Affiliation(s)
- Feroz Ahmad
- Institute of Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom
| | - David S Leake
- Institute of Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom
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16
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Ahmad F, Leake DS. Antioxidants inhibit low density lipoprotein oxidation less at lysosomal pH: A possible explanation as to why the clinical trials of antioxidants might have failed. Chem Phys Lipids 2018. [PMID: 29518380 PMCID: PMC5989656 DOI: 10.1016/j.chemphyslip.2018.03.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Oxidised low density lipoprotein (LDL) was considered to be important in the pathogenesis of atherosclerosis, but the large clinical trials of antioxidants, including the first one using probucol (the PQRST Trial), failed to show benefit and have cast doubt on the importance of oxidised LDL. We have shown previously that LDL oxidation can be catalysed by iron in the lysosomes of macrophages. The aim of this study was therefore to investigate the effectiveness of antioxidants in preventing LDL oxidation at lysosomal pH and also establish the possible mechanism of oxidation. Probucol did not effectively inhibit the oxidation of LDL at lysosomal pH, as measured by conjugated dienes or oxidised cholesteryl esters or tryptophan residues in isolated LDL or by ceroid formation in the lysosomes of macrophage-like cells, in marked contrast to its highly effective inhibition of LDL oxidation at pH 7.4. LDL oxidation at lysosomal pH was inhibited very effectively for long periods by N,N'-diphenyl-1,4-phenylenediamine, which is more hydrophobic than probucol and has been shown by others to inhibit atherosclerosis in rabbits, and by cysteamine, which is a hydrophilic antioxidant that accumulates in lysosomes. Iron-induced LDL oxidation might be due to the formation of the superoxide radical, which protonates at lysosomal pH to form the much more reactive, hydrophobic hydroperoxyl radical, which can enter LDL and reach its core. Probucol resides mainly in the surface monolayer of LDL and would not effectively scavenge hydroperoxyl radicals in the core of LDL. This might explain why probucol failed to protect against atherosclerosis in various clinical trials. The oxidised LDL hypothesis of atherosclerosis now needs to be re-evaluated using different and more effective antioxidants that protect against the lysosomal oxidation of LDL.
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Affiliation(s)
- Feroz Ahmad
- Institute of Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom.
| | - David S Leake
- Institute of Cardiovascular and Metabolic Research, University of Reading, Reading, United Kingdom
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17
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Rizzetto F, Mafra D, Barra AB, Pires de Melo G, Abdalla DSP, Leite M. One-Year Conservative Care Using Sodium Bicarbonate Supplementation Is Associated with a Decrease in Electronegative LDL in Chronic Kidney Disease Patients: A Pilot Study. Cardiorenal Med 2017; 7:334-341. [PMID: 29118772 DOI: 10.1159/000478733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 05/31/2017] [Indexed: 12/15/2022] Open
Abstract
Background Chronic kidney disease (CKD) patients develop metabolic acidosis when approaching stages 3 and 4, a period in which accelerated atherogenesis may ensue. Studies in vitro show that low pH may increase low-density lipoprotein (LDL) oxidation, suggesting a role for chronic metabolic acidosis in atherosclerosis. The present study attempted to evaluate the effects of conservative care using oral sodium bicarbonate (NaHCO3) supplementation on the electronegative LDL [LDL(-)], a minimally oxidized LDL, plasma levels in CKD patients. Methods Thirty-one CKD patients were followed by a multidisciplinary team during 15 months of care in which 1.0 mmol/kg/day oral NaHCO3 supplementation was first given in the third month. Blood samples were collected 3 months before the initiation of oral NaHCO3 supplementation (T1), at the time of the beginning of supplementation (T2), and thereafter, each 4 months (T3, T4 and T5) until month 15 of care. Blood parameters and LDL(-) were measured from these collections. Results After 12 months of conservative care, creatinine clearance (MDRD) was kept stable, and serum bicarbonate (HCO3-) increased from 20.5 ± 2.9 to 22.6 ± 1.1 mM (p < 0.003). LDL(-) plasma levels declined from 4.5 ± 3.3 to 2.1 ± 0.9 U/L (p < 0.007) after reaching mean serum HCO3- levels of 22.6 ± 1.1 mM. Conclusions Conservative care using oral NaHCO3 supplementation was able to stabilize renal function and decrease serum levels of LDL(-), a modified proatherogenic lipoprotein, only when mean serum HCO3- levels approached 22 mM. This study constitutes evidence that alkali therapy, in addition to its beneficial effect on renal disease progression, might serve as a preventive strategy to attenuate atherogenesis in CKD patients.
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Affiliation(s)
- Felipe Rizzetto
- Division of Nutrition, Federal Hospital of Lagoa (FHL), Rio de Janeiro, Brazil
| | - Denise Mafra
- Graduate Program in Cardiovascular Sciences, Federal Fluminense University (UFF), Niterói, Brazil
| | - Ana Beatriz Barra
- Division of Nephrology, Federal Hospital of Lagoa (FHL), Rio de Janeiro, Brazil
| | | | | | - Maurilo Leite
- Division of Nephrology, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
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18
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Abstract
Ferritin and increased iron stores first appeared on the list of cardiovascular risk factors more than 30 years ago and their causal role in the pathogenesis of atherosclerosis has been heavily discussed since the early 1990s. It seems that besides traditional factors such as hyperlipoproteinemia, hypertension, diabetes mellitus, obesity, physical inactivity, smoking and family history, high iron stores represent an additional parameter that could modify individual cardiovascular risk. The role of iron in the pathogenesis of atherosclerosis was originally primarily associated with its ability to catalyze the formation of highly reactive free oxygen radicals and the oxidation of atherogenic lipoproteins. Later, it became clear that the mechanism is more complex. Atherosclerosis is a chronic fibroproliferative inflammatory process and iron, through increased oxidation stress as well as directly, can control both native and adaptive immune responses. Within the arterial wall, iron affects all of the cell types that participate in the atherosclerotic process (monocytes/macrophages, endothelial cells, vascular smooth muscle cells and platelets). Most intracellular iron is bound in ferritin, whereas redox-active iron forms labile iron pool. Pro-inflammatory and anti-inflammatory macrophages within arterial plaque differ with regard to the amount of intracellular iron and most probably with regard to their labile iron pool. Yet, the relation between plasma ferritin and intracellular labile iron pool has not been fully clarified. Data from population studies document that the consumption of meat and lack of physical activity contribute to increased iron stores. Patients with hereditary hemochromatosis, despite extreme iron storage, do not show increased manifestation of atherosclerosis probably due to the low expression of hepcidin in macrophages.
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Affiliation(s)
- P Kraml
- Second Department of Internal Medicine, Third Faculty of Medicine, Charles University and University Hospital Královské Vinohrady, Prague, Czech Republic.
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19
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Crielaard BJ, Lammers T, Rivella S. Targeting iron metabolism in drug discovery and delivery. Nat Rev Drug Discov 2017; 16:400-423. [PMID: 28154410 PMCID: PMC5455971 DOI: 10.1038/nrd.2016.248] [Citation(s) in RCA: 225] [Impact Index Per Article: 32.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Iron fulfils a central role in many essential biochemical processes in human physiology; thus, proper processing of iron is crucial. Although iron metabolism is subject to relatively strict physiological control, numerous disorders, such as cancer and neurodegenerative diseases, have recently been linked to deregulated iron homeostasis. Consequently, iron metabolism constitutes a promising and largely unexploited therapeutic target for the development of new pharmacological treatments for these diseases. Several iron metabolism-targeted therapies are already under clinical evaluation for haematological disorders, and these and newly developed therapeutic agents are likely to have substantial benefit in the clinical management of iron metabolism-associated diseases, for which few efficacious treatments are currently available.
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Affiliation(s)
- Bart J. Crielaard
- Department of Polymer Chemistry and Bioengineering, Zernike Institute for Advanced Materials, Faculty of Mathematics and Natural Sciences, University of Groningen, Groningen, The Netherlands
- W.J. Kolff Institute for Biomedical Engineering and Materials Science, University Medical Center Groningen, Groningen, The Netherlands
| | - Twan Lammers
- Department of Nanomedicine and Theranostics, Institute for Experimental Molecular Imaging, University Clinic and Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany
- Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
- Department of Targeted Therapeutics, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, The Netherlands
| | - Stefano Rivella
- Children’s Hospital of Philadelphia, Abramson Research Center, Philadelphia, PA, United States of America
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20
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Lapenna D, Ciofani G, Obletter G. Iron as a catalyst of human low-density lipoprotein oxidation: Critical factors involved in its oxidant properties. J Trace Elem Med Biol 2017; 41:111-118. [PMID: 28347457 DOI: 10.1016/j.jtemb.2017.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/29/2017] [Accepted: 02/14/2017] [Indexed: 10/20/2022]
Abstract
Iron-induced human LDL oxidation, which is relevant to atherosclerosis, has not yet been properly investigated. We addressed such issue using iron(II) and (III) basically in the presence of phosphates, which are present in vivo and influence iron oxidative properties, at pH 4.5 and 7.4, representative, respectively, of the lysosomal and plasma environment. In 10mM phosphate buffered saline (PBS), iron(II) induces substantial LDL oxidation at pH 4.5 at low micromolar concentrations, while at pH 7.4 has low oxidative effects; iron(III) promotes small LDL oxidation only at pH 4.5. In 10mM sodium acetate/NaCl buffer, pH 4.5, iron-induced LDL oxidation is far higher than in PBS, highlighting the relevance of phosphates in the inhibitory modulation of iron-induced LDL oxidation. LDL oxidation is related to iron binding to the protein and lipid moiety of LDL, and requires the presence of iron(II) bound to LDL together with iron(III). Chemical modification of LDL carboxyl groups, which could bind iron especially at pH 4.5, decreases significantly iron binding to LDL and iron-induced LDL oxidation. Hydroxyl radical scavengers are ineffective on iron-induced LDL oxidation, which is inhibited by metal chelation, scavengers of alkoxyl/peroxyl radicals, or removal of LDL lipid hydroperoxides (LOOH). Overall, substantial human LDL oxidation is induced LOOH-dependently by iron(II) at pH 4.5 even in the presence of phosphates, suggesting the occurrence of iron(II)-induced LDL oxidation in vivo within lysosomes, where pH is about 4.5, iron(II) and phosphates coexist, plasma with its antioxidants is absent, and glutathione peroxidase is poorly expressed resulting in LOOH accumulation.
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Affiliation(s)
- Domenico Lapenna
- Dipartimento di Medicina e Scienze dell'Invecchiamento, and Laboratorio di Fisiopatologia dello Stress Ossidativo, Centro Scienze dell'Invecchiamento e Medicina Traslazionale (CeSI-MeT), Center of Excellence on Aging, Università degli Studi "G. d'Annunzio" Chieti-Pescara, 66100, Chieti, Italy.
| | - Giuliano Ciofani
- Dipartimento di Medicina e Scienze dell'Invecchiamento, and Laboratorio di Fisiopatologia dello Stress Ossidativo, Centro Scienze dell'Invecchiamento e Medicina Traslazionale (CeSI-MeT), Center of Excellence on Aging, Università degli Studi "G. d'Annunzio" Chieti-Pescara, 66100, Chieti, Italy
| | - Gabriele Obletter
- Dipartimento di Medicina e Scienze dell'Invecchiamento, and Laboratorio di Fisiopatologia dello Stress Ossidativo, Centro Scienze dell'Invecchiamento e Medicina Traslazionale (CeSI-MeT), Center of Excellence on Aging, Università degli Studi "G. d'Annunzio" Chieti-Pescara, 66100, Chieti, Italy
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Öörni K, Rajamäki K, Nguyen SD, Lähdesmäki K, Plihtari R, Lee-Rueckert M, Kovanen PT. Acidification of the intimal fluid: the perfect storm for atherogenesis. J Lipid Res 2014; 56:203-14. [PMID: 25424004 DOI: 10.1194/jlr.r050252] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Atherosclerotic lesions are often hypoxic and exhibit elevated lactate concentrations and local acidification of the extracellular fluids. The acidification may be a consequence of the abundant accumulation of lipid-scavenging macrophages in the lesions. Activated macrophages have a very high energy demand and they preferentially use glycolysis for ATP synthesis even under normoxic conditions, resulting in enhanced local generation and secretion of lactate and protons. In this review, we summarize our current understanding of the effects of acidic extracellular pH on three key players in atherogenesis: macrophages, apoB-containing lipoproteins, and HDL particles. Acidic extracellular pH enhances receptor-mediated phagocytosis and antigen presentation by macrophages and, importantly, triggers the secretion of proinflammatory cytokines from macrophages through activation of the inflammasome pathway. Acidity enhances the proteolytic, lipolytic, and oxidative modifications of LDL and other apoB-containing lipoproteins, and strongly increases their affinity for proteoglycans, and may thus have major effects on their retention and the ensuing cellular responses in the arterial intima. Finally, the decrease in the expression of ABCA1 at acidic pH may compromise cholesterol clearance from atherosclerotic lesions. Taken together, acidic extracellular pH amplifies the proatherogenic and proinflammatory processes involved in atherogenesis.
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Development of a population pharmacokinetic model characterizing the tissue distribution of azithromycin in healthy subjects. Antimicrob Agents Chemother 2014; 58:6675-84. [PMID: 25155592 DOI: 10.1128/aac.02904-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Recent clinical trials indicate that the use of azithromycin is associated with the emergence of macrolide resistance. The objective of our study was to simultaneously characterize free target site concentrations and correlate them with the MIC90s of clinically relevant pathogens. Azithromycin (500 mg once daily [QD]) was administered orally to 6 healthy male volunteers for 3 days. The free concentrations in the interstitial space fluid (ISF) of muscle and subcutaneous fat tissue as well as the total concentrations in plasma and polymorphonuclear leukocytes (PMLs) were determined on days 1, 3, 5, and 10. All concentrations were modeled simultaneously in NONMEM 7.2 using a tissue distribution model that accounts for nonlinear protein binding and ionization state at physiological pH. The model performance and parameter estimates were evaluated via goodness-of-fit plots and nonparametric bootstrap analysis. The model we developed described the concentrations at all sampling sites reasonably well and showed that the overall pharmacokinetics of azithromycin is driven by the release of the drug from acidic cell/tissue compartments. The model-predicted unionized azithromycin (AZM) concentrations in the cytosol of PMLs (6.0 ± 1.2 ng/ml) were comparable to the measured ISF concentrations in the muscle (8.7 ± 2.9 ng/ml) and subcutis (4.1 ± 2.4 ng/ml) on day 10, whereas the total PML concentrations were >1,000-fold higher (14,217 ± 2,810 ng/ml). The total plasma and free ISF concentrations were insufficient to exceed the MIC90s of the skin pathogens at all times. Our results indicate that the slow release of azithromycin from low pH tissue/cell compartments is responsible for the long terminal half-life of the drug and thus the extended period of time during which free concentrations reside at subinhibitory concentrations.
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Iron and atherosclerosis: nailing down a novel target with magnetic resonance. J Cardiovasc Transl Res 2014; 7:533-42. [PMID: 24590608 DOI: 10.1007/s12265-014-9551-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 02/14/2014] [Indexed: 12/21/2022]
Abstract
Iron is an essential mineral in many proteins and enzymes in human physiology, with limited means of iron elimination to maintain iron balance. Iron accrual incurs various pathological mechanisms linked to cardiovascular disease. In atherosclerosis, iron catalyzes the creation of reactive oxygen free radicals that contribute to lipid modification, which is essential to atheroma formation. Inflammation further fuels iron-related pathologic processes associated with plaque progression. Given iron's role in atherosclerosis development, in vivo detection techniques sensitive iron are needed for translational studies targeting iron for earlier diagnosis and treatment. Magnetic resonance imaging is uniquely able to quantify iron in human tissues noninvasively and without ionizing radiation, offering appealing for longitudinal and interventional studies. Particularly intriguing is iron's complementary biology vs. calcium, which is readily detectable by computed tomography. This review summarizes the role of iron in atherosclerosis with considerable implications for novel diagnostic and therapeutic approaches.
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Wallert M, Schmölz L, Galli F, Birringer M, Lorkowski S. Regulatory metabolites of vitamin E and their putative relevance for atherogenesis. Redox Biol 2014; 2:495-503. [PMID: 24624339 PMCID: PMC3949092 DOI: 10.1016/j.redox.2014.02.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 02/07/2014] [Accepted: 02/11/2014] [Indexed: 02/07/2023] Open
Abstract
Vitamin E is likely the most important antioxidant in the human diet and α-tocopherol is the most active isomer. α-Tocopherol exhibits anti-oxidative capacity in vitro, and inhibits oxidation of LDL. Beside this, α-tocopherol shows anti-inflammatory activity and modulates expression of proteins involved in uptake, transport and degradation of tocopherols, as well as the uptake, storage and export of lipids such as cholesterol. Despite promising anti-atherogenic features in vitro, vitamin E failed to be atheroprotective in clinical trials in humans. Recent studies highlight the importance of long-chain metabolites of α-tocopherol, which are formed as catabolic intermediate products in the liver and occur in human plasma. These metabolites modulate inflammatory processes and macrophage foam cell formation via mechanisms different than that of their metabolic precursor α-tocopherol and at lower concentrations. Here we summarize the controversial role of vitamin E as a preventive agent against atherosclerosis and point the attention to recent findings that highlight a role of these long-chain metabolites of vitamin E as a proposed new class of regulatory metabolites. We speculate that the metabolites contribute to physiological as well as pathophysiological processes.
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Affiliation(s)
- Maria Wallert
- Department of Nutritional Biochemistry, Institute of Nutrition, Friedrich Schiller University Jena, Germany
| | - Lisa Schmölz
- Department of Nutritional Biochemistry, Institute of Nutrition, Friedrich Schiller University Jena, Germany
| | - Francesco Galli
- Laboratory of Molecular Modeling and Chemoinformatics, Department of Chemistry, University of Perugia, Perugia, Italy
| | - Marc Birringer
- Department of Nutritional, Food and Consumer Studies, University of Applied Sciences Fulda, Germany
| | - Stefan Lorkowski
- Department of Nutritional Biochemistry, Institute of Nutrition, Friedrich Schiller University Jena, Germany
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25
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Samsam Shariat SZA, Mostafavi SA, Khakpour F. Antioxidant effects of vitamins C and e on the low-density lipoprotein oxidation mediated by myeloperoxidase. IRANIAN BIOMEDICAL JOURNAL 2013; 17:22-8. [PMID: 23279831 DOI: 10.6091/ibj.1092.2012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Oxidative modification of low-density lipoprotein (LDL) appears to be an early step in the pathogenesis of atherosclerosis. Meanwhile, myeloperoxidase (MPO)-catalyzed reaction is one of the potent pathway for LDL oxidation in vivo. The aim of this study was to evaluate in vitro antioxidant effects of vitamins C and E on LDL oxidation mediated by MPO. METHODS MPO was isolated from fresh plasma by sequential centrifugation using density ultracentrifugation. It was incubated with LDL and the LDL oxidation level was determined spectrophotometrically by measuring conjugated diene absorbance at 234 nm. Furthermore, vitamin C (50-200 mM) and vitamin E (10-40 mM) were added and the LDL oxidation level was determined. RESULTS The purity index of MPO and its enzymatic activity were 0.69 and 1127 U/mg protein, respectively. It was demonstrated that vitamin C in vitro inhibited LDL oxidation mediated by MPO; however, vitamin E was unable to act in the same way. The protection by vitamin C was concentration dependent and maximum protective effect of vitamin C was observed at 150 mM, where about 64% of the LDL oxidation was inhibited. Vitamin C increased lag time of LDL oxidation mediated by MPO up to 2.4 times. CONCLUSION It can be concluded from our results that vitamin C is able to improve LDL resistance to oxidative modification in vitro. In addition, vitamin C might be effective in LDL oxidation mediated by MPO in vivo, resulting in reduction of atherosclerosis process rate.
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Affiliation(s)
- Seyed Ziyae Aldin Samsam Shariat
- School of Pharmacy and Pharmaceutical Sciences and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan
| | - Sayed Abolfazl Mostafavi
- School of Pharmacy and Pharmaceutical Sciences and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan
| | - Farzad Khakpour
- School of Pharmacy and Pharmaceutical Sciences and Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan
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Zhong S, Xu J, Li P, Tsukamoto H. Caveosomal oxidative stress causes Src-p21ras activation and lysine 63 TRAF6 protein polyubiquitination in iron-induced M1 hepatic macrophage activation. J Biol Chem 2012; 287:32078-84. [PMID: 22829592 DOI: 10.1074/jbc.m112.377358] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proinflammatory M1 activation of hepatic macrophages (HM) is critical in pathogenesis of hepatitis, but its mechanisms are still elusive. Our earlier work demonstrates the role of ferrous iron (Fe(2+)) as a pathogen-associated molecular pattern-independent agonist for activation of IκB kinase (IKK) and NF-κB in HM via activation and interaction of p21(ras), transforming growth factor β-activated kinase-1 (TAK1), and phosphatidylinositol 3-kinase (PI3K) in caveosomes. However, iron-induced signaling upstream of these kinases is not known. Here we show that Fe(2+) induces generation of superoxide anion (O(2)()) in endosomes, reduces protein-tyrosine phosphatase (PTP) activity, and activates Src at 2∼10 min of Fe(2+) addition to rat primary HM culture. Superoxide dismutase (SOD) blocks O(2)() generation, PTP inhibition, and Src activation. Fe(2+)-induced p21(ras) activity is abrogated with the Src inhibitor PP2 and SOD. Fe(2+) stimulates Lys(63)-linked polyubiquitination (polyUb) of TRAF6 in caveosomes, and a dominant negative K63R mutant of ubiquitin or SOD prevents iron-induced TRAF6 polyUb and TAK1 activation. These results demonstrate that Fe(2+)-generated O(2)() mediates p21(ras) and TAK1 activation via PTP inhibition and Lys(63)-polyUb of TRAF6 in caveosomes for proinflammatory M1 activation in HM.
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Affiliation(s)
- Shuping Zhong
- Southern California Research Center for Alcoholic Liver and Pancreatic Diseases and Cirrhosis, University of Southern California, Los Angeles,California 90033, USA
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