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Olsen T, Refsum H, Eiser AR. Hyperhomocysteinemia Is Associated With a Myriad of Age-Related Illnesses: A Potential Role for Metal Toxicity. Mayo Clin Proc 2024; 99:1362-1368. [PMID: 38935017 PMCID: PMC11374489 DOI: 10.1016/j.mayocp.2024.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 03/15/2024] [Accepted: 04/24/2024] [Indexed: 06/28/2024]
Affiliation(s)
- Thomas Olsen
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Helga Refsum
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Pharmacology, University of Oxford, Oxford, UK
| | - Arnold R Eiser
- Center for Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
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2
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Induction of apoptosis and autosis in cardiomyocytes by the combination of homocysteine and copper via NOX-mediated p62 expression. Cell Death Dis 2022; 8:75. [PMID: 35190552 PMCID: PMC8860999 DOI: 10.1038/s41420-022-00870-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 01/12/2022] [Accepted: 02/01/2022] [Indexed: 01/01/2023]
Abstract
High levels of homocysteine (Hcy) associated with cardiovascular events are accompanied by increased copper (Cu) concentrations in the blood. Hcy has been shown to promote endothelial dysfunction, whereas the effect of Hcy on cardiomyocytes and the role of Cu in the pathogenesis remain less understood. In the present study, it is demonstrated that the combination of Hcy and Cu2+-induced apoptosis and autosis of cardiomyocytes simultaneously, and thus led to cardiac dysfunction in hyperhomocysteinemic rats. These effects were associated with p22phox activation and NADPH oxidase (NOX)-mediated p62 upregulation. Inhibition of the expression of p22phox or p62 in cardiomyocytes significantly attenuated Hcy and Cu2+-mediated reactive oxygen species (ROS) generation and cell death. Furthermore, interrupting the NOX-p62 axis prevented diastolic dysfunction in hyperhomocysteinemic rats (HcyR). These findings establish that the induction of apoptosis and autosis of cardiomyocytes through stimulating the NOX-p62-signaling pathway constitutes a novel mechanism of Hcy and Cu-induced cardiac dysfunction.
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Gupta M, Meehan-Atrash J, Strongin RM. Identifying a role for the interaction of homocysteine and copper in promoting cardiovascular-related damage. Amino Acids 2021; 53:739-744. [PMID: 33886000 DOI: 10.1007/s00726-021-02979-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/03/2021] [Indexed: 12/15/2022]
Abstract
Observations that copper and homocysteine levels are simultaneously elevated in patients with cardiovascular disease has generated interest in investigating the interactions between copper and homocysteine. Several prior studies have shown that complexes of copper and homocysteine are toxic, leading to cardiovascular damage in vitro. It is not clear, however, why related effects do not occur with other structurally similar, more abundant cellular thiols such as glutathione and cysteine. Herein, a mechanism for a selective redox interaction between copper and homocysteine is demonstrated. It involves a kinetically favored intramolecular hydrogen atom transfer that results in an alpha-amino carbon-centered radical known to promote biomolecular damage.
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Affiliation(s)
- Megha Gupta
- Department of Chemistry, Portland State University, Portland, OR, 97207, USA
| | | | - Robert M Strongin
- Department of Chemistry, Portland State University, Portland, OR, 97207, USA.
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4
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Liu J, Chen C, Liu Y, Sun X, Ding X, Qiu L, Han P, James Kang Y. Trientine selectively delivers copper to the heart and suppresses pressure overload-induced cardiac hypertrophy in rats. Exp Biol Med (Maywood) 2018; 243:1141-1152. [PMID: 30472883 DOI: 10.1177/1535370218813988] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Dietary copper supplementation reverses pressure overload-induced cardiac hypertrophy by copper replenishment in the heart. A copper-selective chelator, trientine (triethylenetetramine [TETA]), reverses left ventricular hypertrophy associated with diabetes also by copper replenishment in the heart. The present study was undertaken to address the critical issue how TETA delivers copper to the heart. Adult male Sprague-Dawley rats were subjected to transverse aortic constriction (TAC) to induce cardiac hypertrophy. Eight weeks after the TAC surgery, cardiac hypertrophy was developed and copper content in the heart was reduced. TETA was then administrated by gavage in two different dosages (21.9 or 87.6 mg/kg day) for six weeks. The results showed that in the lower dosage, TETA replenished copper contents in the heart, along with a decrease in the copper concentration in the blood and kidney, and an increase in the urine. In the higher dosage, TETA did not replenish copper contents in the heart, but markedly increased copper concentrations in the urine and decreased those in the blood and kidney. Neither lower nor higher TETA dosage altered copper concentrations in other organs. Corresponding to myocardial copper replenishment, the lower dose TETA suppresses cardiac hypertrophy, as judged by a reduction in the left ventricle wall thickness and a decrease in the heart size, and diminished cardiac fibrosis, as reflected by a decrease in collagen I content. TETA in the higher dose not only did not suppress cardiac hypertrophy, but also caused cardiac hypertrophy in sham-operated rats. TETA-mediated myocardial copper restoration is independent of copper transporter-1 or -2 but related to an energy-dependent transportation. This study demonstrates that low-dose TETA functions as a copper chaperone, selectively delivering copper to the copper-deprived heart through an active transportation; in higher doses, TETA simply retains its chelator function, removing copper from the body by urinary excretion. Impact statement Our study reveals that TETA, traditionally regarded as a copper chelator, in lower doses delivers copper selectively to the heart through a mechanism independent of copper transporter-1 or -2. Copper supplementation by a lower dose of TETA suppresses pressure overload-induced cardiac hypertrophy. Since ischemic heart disease and hypertrophic cardiomyopathy are accompanied by myocardial copper loss, this approach of using a lower dose of TETA to supplement copper to the heart would help treat the disease condition of patients with such cardiac events.
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Affiliation(s)
- Jiaming Liu
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Chen Chen
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yinjie Liu
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xiaorong Sun
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Xueqin Ding
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Liying Qiu
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Pengfei Han
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Y James Kang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu 610041, China.,Memphis Institute of Regenerative Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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5
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Yang F, Qi X, Gao Z, Yang X, Zheng X, Duan C, Zheng J. Homocysteine injures vascular endothelial cells by inhibiting mitochondrial activity. Exp Ther Med 2016; 12:2247-2252. [PMID: 27698720 DOI: 10.3892/etm.2016.3564] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 05/09/2016] [Indexed: 12/20/2022] Open
Abstract
The aim of the present study was to investigate the role of homocysteine (Hcy) in the pathogenesis of pulmonary embolism (PE) and the associated molecular mechanisms in human umbilical vein endothelial cells (HUVECs). Hcy contents were detected with high-performance liquid chromatography. Apoptosis was detected by flow cytometry using Annexin-V staining. Cytochrome c oxidase (COX) activity was assessed with an enzyme activity assay, and the expression levels of COX 17 were determined by western blot analysis. Intracellular reactive oxygen species levels were measured using a microplate reader with a fluorescence probe. The results demonstrated that, compared with the control group, the serum Hcy levels were significantly elevated in the PE group, suggesting that Hcy may be an indicator for PE. Following treatment with Hcy, the apoptosis rate was markedly elevated in HUVECs. Moreover, Hcy decreased COX activity and downregulated the expression of COX 17 in HUVECs. Furthermore, Hcy increased the ROS levels in these endothelial cells. However, all the above-mentioned physiopathological changes induced by Hcy in HUVECs could be restored by folic acid. In conclusion, the results of the present study demonstrated that Hcy inhibited COX activity, downregulated COX 17 expression, increased intracellular ROS levels and enhanced apoptosis in endothelial cells.
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Affiliation(s)
- Fengyong Yang
- Intensive Care Unit, The People's Hospital of Laiwu, Laiwu, Shandong 271199, P.R. China
| | - Xiujing Qi
- Intensive Care Unit, The People's Hospital of Laiwu, Laiwu, Shandong 271199, P.R. China
| | - Zheng Gao
- Intensive Care Unit, The People's Hospital of Laiwu, Laiwu, Shandong 271199, P.R. China
| | - Xingju Yang
- Intensive Care Unit, The People's Hospital of Laiwu, Laiwu, Shandong 271199, P.R. China
| | - Xingfeng Zheng
- Burn Center, Shanghai Hospital, Second Military Medical University, Shanghai 200433, P.R. China
| | - Chonghao Duan
- Intensive Care Unit, The People's Hospital of Laiwu, Laiwu, Shandong 271199, P.R. China
| | - Jian Zheng
- Department of Thoracic Surgery, The People's Hospital of Laicheng, Laiwu, Shandong 271199, P.R. China
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Zheng L, Han P, Liu J, Li R, Yin W, Wang T, Zhang W, Kang YJ. Role of copper in regression of cardiac hypertrophy. Pharmacol Ther 2014; 148:66-84. [PMID: 25476109 DOI: 10.1016/j.pharmthera.2014.11.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 02/07/2023]
Abstract
Pressure overload causes an accumulation of homocysteine in the heart, which is accompanied by copper depletion through the formation of copper-homocysteine complexes and the excretion of the complexes. Copper supplementation recovers cytochrome c oxidase (CCO) activity and promotes myocardial angiogenesis, along with the regression of cardiac hypertrophy and the recovery of cardiac contractile function. Increased copper availability is responsible for the recovery of CCO activity. Copper promoted expression of angiogenesis factors including vascular endothelial growth factor (VEGF) in endothelial cells is responsible for angiogenesis. VEGF receptor-2 (VEGFR-2) is critical for hypertrophic growth of cardiomyocytes and VEGFR-1 is essential for the regression of cardiomyocyte hypertrophy. Copper, through promoting VEGF production and suppressing VEGFR-2, switches the VEGF signaling pathway from VEGFR-2-dependent to VEGFR-1-dependent, leading to the regression of cardiomyocyte hypertrophy. Copper is also required for hypoxia-inducible factor-1 (HIF-1) transcriptional activity, acting on the interaction between HIF-1 and the hypoxia responsible element and the formation of HIF-1 transcriptional complex by inhibiting the factor inhibiting HIF-1. Therefore, therapeutic targets for copper supplementation-induced regression of cardiac hypertrophy include: (1) the recovery of copper availability for CCO and other critical cellular events; (2) the activation of HIF-1 transcriptional complex leading to the promotion of angiogenesis in the endothelial cells by VEGF and other factors; (3) the activation of VEGFR-1-dependent regression signaling pathway in the cardiomyocytes; and (4) the inhibition of VEGFR-2 through post-translational regulation in the hypertrophic cardiomyocytes. Future studies should focus on target-specific delivery of copper for the development of clinical application.
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Affiliation(s)
- Lily Zheng
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Pengfei Han
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Jiaming Liu
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Rui Li
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Wen Yin
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Tao Wang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Wenjing Zhang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China
| | - Y James Kang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China; Department of Pharmacology and Toxicology, University of Louisville, Louisville, KY 40292, USA.
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7
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Disturbance of copper homeostasis is a mechanism for homocysteine-induced vascular endothelial cell injury. PLoS One 2013; 8:e76209. [PMID: 24204604 PMCID: PMC3799909 DOI: 10.1371/journal.pone.0076209] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 08/21/2013] [Indexed: 02/05/2023] Open
Abstract
Elevation of serum homocysteine (Hcy) levels is a risk factor for cardiovascular diseases. Previous studies suggested that Hcy interferes with copper (Cu) metabolism in vascular endothelial cells. The present study was undertaken to test the hypothesis that Hcy-induced disturbance of Cu homeostasis leads to endothelial cell injury. Exposure of human umbilical vein endothelial cells (HUVECs) to concentrations of Hcy at 0.01, 0.1 or 1 mM resulted in a concentration-dependent decrease in cell viability and an increase in necrotic cell death. Pretreatment of the cells with a final concentration of 5 µM Cu in cultures prevented the effects of Hcy. Hcy decreased intracellular Cu concentrations. HPLC-ICP-MS analysis revealed that Hcy caused alterations in the distribution of intracellular Cu; more Cu was redistributed to low molecular weight fractions. ESI-Q-TOF detected the formation of Cu-Hcy complexes. Hcy also decreased the protein levels of Cu chaperone COX17, which was accompanied by a decrease in the activity of cytochrome c oxidase (CCO) and a collapse of mitochondrial membrane potential. These effects of Hcy were all preventable by Cu pretreatment. The study thus demonstrated that Hcy disturbs Cu homeostasis and limits the availability of Cu to critical molecules such as COX17 and CCO, leading to mitochondrial dysfunction and endothelial cell injury.
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8
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Zuo X, Dong D, Sun M, Xie H, Kang YJ. Homocysteine restricts copper availability leading to suppression of cytochrome C oxidase activity in phenylephrine-treated cardiomyocytes. PLoS One 2013; 8:e67549. [PMID: 23818984 PMCID: PMC3688604 DOI: 10.1371/journal.pone.0067549] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2013] [Accepted: 05/20/2013] [Indexed: 02/05/2023] Open
Abstract
Cardiomyocyte hypertrophy induced by phenylephrine (PE) is accompanied by suppression of cytochrome c oxidase (CCO) activity, and copper (Cu) supplementation restores CCO activity and reverses the hypertrophy. The present study was aimed to understand the mechanism of PE-induced decrease in CCO activity. Primary cultures of neonatal rat cardiomyocytes were treated with PE at a final concentration of l00 µM in cultures for 72 h to induce cell hypertrophy. The CCO activity was determined by enzymatic assay and changes in CCO subunit COX-IV as well as copper chaperones for CCO (COX17, SCO2, and COX11) were determined by Western blotting. PE treatment increased both intracellular and extracellular homocysteine concentrations and decreased intracellular Cu concentrations. Studies in vitro found that homocysteine and Cu form complexes. Inhibition of the intracellular homocysteine synthesis in the PE-treated cardiomyocytes prevented the increase in the extracellular homocysteine concentration, retained the intracellular Cu concentration, and preserved the CCO activity. PE treatment decreased protein concentrations of the COX-IV, and the Cu chaperones COX17, COX11, and SCO2. These PE effects were prevented by either inhibition of the intracellular homocysteine synthesis or Cu supplementation. Therefore, PE-induced elevation of homocysteine restricts Cu availability through its interaction with Cu and suppression of Cu chaperones, leading to the decrease in CCO enzyme activity.
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Affiliation(s)
- Xiao Zuo
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Daoyin Dong
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Miao Sun
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Huiqi Xie
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Y. James Kang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, United States of America
- * E-mail:
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9
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Celik C, Bastu E, Abali R, Alpsoy S, Guzel EC, Aydemir B, Yeh J. The relationship between copper, homocysteine and early vascular disease in lean women with polycystic ovary syndrome. Gynecol Endocrinol 2013; 29:488-91. [PMID: 23480818 DOI: 10.3109/09513590.2013.774361] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study investigates copper (Cu) levels and vascular dysfunction in lean women with polycystic ovary syndrome (PCOS). 44 subjects with PCOS, diagnosed according to Rotterdam criteria, and 42 healthy subjects matched for body mass index and age. Comparison of serum Cu, homocysteine, carotid intima-media thickness (CIMT), brachial artery flow mediated dilation (FMD) was carried out between PCOS patients and the control group. Clinical study was done in Namik Kemal University School of Medicine. The CIMT and concentration of Cu in PCOS patients was significantly higher than the healthy controls. FMD levels in PCOS patients were significantly lower than those in controls. In PCOS patients, CIMT was correlated with estrogen and Cu levels. However, FMD was correlated with age and Cu levels. Among these contributing factors, Cu levels were correlated with a change in CIMT and FMD. CIMT and FMD in PCOS patients were related to Cu levels as well as several cardiovascular risk factors. Thus, increased Cu levels may be responsible for the increased risk of early vascular disease in women with PCOS.
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Affiliation(s)
- Cem Celik
- Department of Gynecology and Obstetrics, Faculty of Medicine, Namik Kemal University, Tekirdag, Turkey.
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10
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Chen CH, Beard RS, Bearden SE. Homocysteine impairs endothelial wound healing by activating metabotropic glutamate receptor 5. Microcirculation 2012; 19:285-95. [PMID: 22221504 DOI: 10.1111/j.1549-8719.2012.00159.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Hcy is an independent risk factor for cerebrovascular disease and cognitive impairment. The purpose of this study was to elucidate the role of mGluR5 in Hcy-mediated impairment of cerebral endothelial wound repair. METHODS Mouse CMVECs (bEnd.3) were used in conjunction with directed pharmacology and shRNA. AutoDock was used to simulate the docking of ligand-receptor interactions. RESULTS Hcy (20 μM) significantly increased Cx43-pS368 by mGluR5- and PKC-dependent mechanisms. Hcy attenuated wound repair by an mGluR5-dependent mechanism over the six-day study period but did not alter cell proliferation in a proliferation assay, suggesting that the attenuation of wound repair may be due to dysfunctional migration in HHcy. Hcy increased the expression of Cx43 and Cx43-pS368 at the wound edge by activating mGluR5. Direct activation of mGluR5, using the specific agonist CHPG, was sufficient to reproduce the results whereas KO of mGluR5 with shRNA, or inhibition with MPEP, blocked the response to Hcy. CONCLUSIONS Inhibition of mGluR5 activation could be a novel strategy for promoting endothelial wound repair in patients with HHcy. Activation of mGluR5 may be a viable strategy for disrupting angiogenesis.
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Affiliation(s)
- Cheng-Hung Chen
- Department of Biological Sciences, Idaho State University, Pocatello, Idaho 83209-8007, USA
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11
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Ischemia-induced Copper Loss and Suppression of Angiogenesis in the Pathogenesis of Myocardial Infarction. Cardiovasc Toxicol 2012; 13:1-8. [DOI: 10.1007/s12012-012-9174-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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12
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Muzaffar S, Jeremy JY, Angelini GD, Shukla N. NADPH oxidase 4 mediates upregulation of type 4 phosphodiesterases in human endothelial cells. J Cell Physiol 2012; 227:1941-50. [PMID: 21732365 DOI: 10.1002/jcp.22922] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The protective actions of prostacyclin (PGI(2) ) are mediated by cyclic AMP (cAMP) which is reduced by type 4 phosphodiesterases (PDE4) which hydrolyze cAMP. Superoxide (O2(-)) from NADPH oxidase (Nox) is associated with impaired PGI(2) bioactivity. The objective of this study, therefore, was to study the relationship between Nox and PDE4 expression in human umbilical vein endothelial cells (HUVECs). HUVECs were incubated with the thromboxane A(2) analog, U46619, 8-isoprostane F(2α) (8IP), or tumor necrosing factor alpha (TNFα) [±iloprost (a PGI(2) analog)] and the expression of PDE4A, B, C, and D and splice variants thereof assessed using Western blotting and qPCR and mRNA silencing of Nox4 and Nox5. Effects on cell replication and angiogenesis were also studied. U46619, 8IP, and TNFα increased the expression of Nox 4 and Nox 5 and all PDE4 isoforms as well as cell replication and tubule formation (index of angiogenesis), effects inhibited by mRNA silencing of Nox4 (but not Nox5) and iloprost and rolipram. These data demonstrate that upregulation of Nox4 leads to an upregulation of PDE4A, B, and D and increased hydrolysis of cAMP which in turn augments cell replication and angiogenesis. This mechanism may be central to vasculopathies associated with endothelial dysfunction since the PGI(2)-cAMP signaling axis plays a key role in mediating functions that include hemostasis and angiogenesis.
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Affiliation(s)
- Saima Muzaffar
- Bristol Heart Institute, University of Bristol, Bristol, UK
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13
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Endothelin-1 (ET-1) and vein graft failure and the therapeutic potential of ET-1 receptor antagonists. Pharmacol Res 2011; 63:483-9. [DOI: 10.1016/j.phrs.2010.10.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 10/27/2010] [Accepted: 10/29/2010] [Indexed: 12/21/2022]
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14
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Kang YJ. Copper and homocysteine in cardiovascular diseases. Pharmacol Ther 2010; 129:321-31. [PMID: 21130114 DOI: 10.1016/j.pharmthera.2010.11.004] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Accepted: 11/08/2010] [Indexed: 02/05/2023]
Abstract
High blood copper (Cu) and homocysteine (Hcy) concentrations have been independently reported as risk factors for cardiovascular diseases. When they are simultaneously measured, a concomitant increase in both parameters in association with vascular dysfunction has been observed. Cu chelator penicillamine can significantly diminish the inhibitory effect of Hcy on endothelial function, which has led to the interpretation that Cu mediates the deleterious effect of Hcy. However, Cu itself has been shown to be beneficial to the cardiovascular system. In particular, Cu promotion of angiogenesis has been well documented. Cu stimulates endothelial cell proliferation and differentiation and promotes microtubule formation in cultured saphenous veins. High levels of Hcy do not affect the process of microtubule formation, but the combination of Cu and Hcy leads to a significant inhibitory effect. Under other conditions, Cu does not affect, but Hcy inhibits, the endothelium-dependent relaxation of blood vessels and the combination of both augments the inhibition. Why does Cu produce adverse effects when it co-exists with Hcy? Cu forms complexes with Hcy and the Cu-Hcy complexes possess a deleterious potential due to their redox properties. Cu chelation can remove Cu from the Cu-Hcy complexes, but leaves behind high levels of Hcy and produces Cu deficiency. An alternative approach should focus on the reduction of Hcy, but maintenance of Cu, making detrimental Cu beneficial. A comprehensive understanding of Cu speciation and a development of selective modulation of Cu coordination to Cu-binding molecules to avoid Cu-Hcy complex formation would effectively improve the condition of cardiovascular disease.
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Affiliation(s)
- Y James Kang
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, PR China.
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15
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Bloor J, Shukla N, Smith FCT, Angelini GD, Jeremy JY. Folic acid administration reduces neointimal thickening, augments neo-vasa vasorum formation and reduces oxidative stress in saphenous vein grafts from pigs used as a model of diabetes. Diabetologia 2010; 53:980-8. [PMID: 20182861 PMCID: PMC3596781 DOI: 10.1007/s00125-010-1680-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Accepted: 12/14/2009] [Indexed: 01/13/2023]
Abstract
AIMS/HYPOTHESIS There is evidence that plasma homocysteine augments vein graft failure and that it augments both micro- and macro-angiopathy in patients with diabetes mellitus. It is therefore suggested that homocysteine may augment vein graft thickening, a major cause of vein graft failure, in diabetic patients, as well as impairing adaptive growth of a new vasa vasorum, possibly through overproduction of superoxide. In order to test these proposals, the effect of folic acid administration, which lowers plasma homocysteine, on vein graft thickening and microvessel density was studied in pigs used as a model of diabetes. METHODS Non-ketotic hyperglycaemia was induced in Landrace pigs by intravenous injection of streptozotocin, and folic acid was fed daily for 1 month. Vein grafts were excised and the thickness of the neointima and media and microvessel density were assessed by planimetry and superoxide formation. RESULTS Plasma total homocysteine was significantly reduced by folic acid in both control and diabetic pigs, whereas glucose was unchanged. Compared with controls, diabetic pigs showed increased neointimal thickness and superoxide formation and decreased adventitial microvessel density. Folic acid reduced neointimal thickness and superoxide formation and augmented microvessel density in diabetic but not in control pigs. CONCLUSIONS Folic acid administration reduces neointimal thickening, augments vasa vasorum neoformation and reduces oxidative stress in saphenous vein grafts from diabetic pigs. Folic acid may therefore be particularly effective in reducing vein graft failure in diabetic patients.
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Affiliation(s)
- J. Bloor
- Department of Vascular Surgery, University of Bristol, Bristol, UK
| | - N. Shukla
- Bristol Heart Institute, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK
| | - F. C. T. Smith
- Department of Vascular Surgery, University of Bristol, Bristol, UK
| | - G. D. Angelini
- Bristol Heart Institute, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK
| | - J. Y. Jeremy
- Bristol Heart Institute, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW, UK,
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Hotston M, Jeremy JY, Bloor J, Greaves NS, Persad R, Angelini G, Shukla N. Homocysteine and copper interact to promote type 5 phosphodiesterase expression in rabbit cavernosal smooth muscle cells. Asian J Androl 2009; 10:905-13. [PMID: 18097500 DOI: 10.1111/j.1745-7262.2008.00380.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
AIM To study the effects of homocysteine and copper on type 5 phosphodiesterase (PDE5) expression in cavernosal vascular smooth muscle cells (CVSMCs) and to investigate superoxide (O(2)(.-)) derived from nicotinamide adenine dinucleotide phosphate oxidase as homocysteine and copper generate O(2)(.-), and O(2)(.-) upregulates PDE5 expression. METHODS CVSMCs derived from rabbit penis were incubated with homocysteine or copper chloride with or without superoxide dismutase (SOD), catalase, sildenafil citrate, or apocynin (nicotinamide adenine dinucleotide phosphate inhibitor) for 16 h. The expression of PDE5 and of glyceraldehyde-3-phosphate dehydrogenase (internal standard) was assessed using Western blot analysis. In parallel, O(2)(.-) was measured spectrophotometrically. RESULTS CuCl(2) alone (up to 10 micromol/L) and homocysteine alone (up to 100 micromol/L) had no effect on O(2)(.-) formation in CVSMCs compared to controls. In combination, however, homocysteine and CuCl(2) markedly increased O(2)(.-) formation, an effect blocked by SOD, catalase, apocynin, and sildenafil (1 micromol/L) when co-incubated over the same time course. PDE5 expression was also significantly increased in CVSMCs incubated with homocysteine and CuCl(2), compared to controls. This effect was also negated by 16-h co-incubation with SOD, catalase, apocynin and sildenafil. CONCLUSION This represents a novel pathogenic mechanism underlying ED, and indicates that the therapeutic actions of prolonged sildenafil use are mediated in part through inhibition of this pathway.
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Affiliation(s)
- Matthew Hotston
- Department of Urology, University of Bristol, 13 Freeland Place, Bristol BS8 4NP, UK.
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Shukla N, Angelini GD, Jeremy JY. The administration of folic acid reduces intravascular oxidative stress in diabetic rabbits. Metabolism 2008; 57:774-81. [PMID: 18502259 DOI: 10.1016/j.metabol.2008.01.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 01/16/2008] [Indexed: 10/22/2022]
Abstract
There is evidence that plasma homocysteine augments angiopathy in patients with diabetes mellitus. Although lowering homocysteine with folic acid improves endothelial function, the precise mechanisms underlying this effect are unknown. To study this area further, the effect of administration of folic acid to diabetic rabbits on intraaortic oxidative stress was studied by assessing the formation of superoxide (O(2)(-)), 8-isoprostane F(2alpha) (8-IPF(2alpha)), and prostacyclin (as 6-keto-PGF(1alpha)) as well as acetylcholine-stimulated relaxation and gp47(phox) content. Nonketotic diabetes mellitus was induced in New Zealand rabbits with alloxan, and low- and high-dose folic acid was administered daily for 1 month. Rabbits were killed, aortae were excised, and rings were prepared. Rings were mounted in an organ bath, and relaxation was elicited with acetylcholine. The O(2)(-) release was measured spectrophotometrically; the gp47(phox) expression, by Western blotting; and the 8-IPF(2alpha) and 6-keto-PGF(1alpha) formation, by enzyme-linked immunosorbent assay. Blood was collected for measurement of homocysteine, red blood cell folate, and glucose. In aortae from the diabetic rabbits, acetylcholine-induced relaxation was significantly impaired compared with that in untreated controls. The O(2)(-) release, p47(phox) expression, and 8-IPF(2alpha) formation were all enhanced and 6-keto-PGF(1alpha) formation was reduced compared with controls. All these effects were reversed by both low- and high-dose folic acid. Plasma total homocysteine was reduced by high-dose, but not low-dose, folic acid. Red blood cell folate was elevated in both groups. The improvement of endothelial function in patients receiving folic acid may be due to inhibition of nicotinamide adenine nucleotide phosphate oxidase (NADPH) oxidase expression and therefore conservation of nitric oxide and prostacyclin bioavailability, 2 vasculoprotective factors.
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Affiliation(s)
- Nilima Shukla
- Department of Cardiac Surgery, Bristol Royal Infirmary, Bristol, UK
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Jeremy JY, Angelini GD, Wan S. Reply to the Editor. J Thorac Cardiovasc Surg 2007. [DOI: 10.1016/j.jtcvs.2007.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Cable DG. Invited commentary. Ann Thorac Surg 2007; 84:49-50. [PMID: 17588381 DOI: 10.1016/j.athoracsur.2007.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2007] [Revised: 05/06/2007] [Accepted: 05/07/2007] [Indexed: 11/16/2022]
Affiliation(s)
- David G Cable
- Louisiana Cardiovascular and Thoracic Institute, 211 4th St, Alexandria, LA 71301, USA.
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