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Zuo X, Ding X, Zhang Y, Kang YJ. Reversal of atherosclerosis by restoration of vascular copper homeostasis. Exp Biol Med (Maywood) 2024; 249:10185. [PMID: 38978540 PMCID: PMC11228934 DOI: 10.3389/ebm.2024.10185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/04/2024] [Indexed: 07/10/2024] Open
Abstract
Atherosclerosis has traditionally been considered as a disorder characterized by the accumulation of cholesterol and thrombotic materials within the arterial wall. However, it is now understood to be a complex inflammatory disease involving multiple factors. Central to the pathogenesis of atherosclerosis are the interactions among monocytes, macrophages, and neutrophils, which play pivotal roles in the initiation, progression, and destabilization of atherosclerotic lesions. Recent advances in our understanding of atherosclerosis pathogenesis, coupled with results obtained from experimental interventions, lead us to propose the hypothesis that atherosclerosis may be reversible. This paper outlines the evolution of this hypothesis and presents corroborating evidence that supports the potential for atherosclerosis regression through the restoration of vascular copper homeostasis. We posit that these insights may pave the way for innovative therapeutic approaches aimed at the reversal of atherosclerosis.
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Affiliation(s)
- Xiao Zuo
- Tasly Stem Cell Biology Laboratory, Tasly Biopharmaceutical Co., Tianjin, China
| | - Xueqin Ding
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yaya Zhang
- Tasly Stem Cell Biology Laboratory, Tasly Biopharmaceutical Co., Tianjin, China
| | - Y James Kang
- Tasly Stem Cell Biology Laboratory, Tasly Biopharmaceutical Co., Tianjin, China
- Regenerative Medicine Research Center, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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2
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Kitala-Tańska K, Socha K, Juśkiewicz J, Krajewska-Włodarczyk M, Majewski M. The Effect of an Elevated Dietary Copper Level on the Vascular Contractility and Oxidative Stress in Middle-Aged Rats. Nutrients 2024; 16:1172. [PMID: 38674863 PMCID: PMC11054332 DOI: 10.3390/nu16081172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 04/28/2024] Open
Abstract
Copper (Cu), being an essential mineral, plays a crucial role in maintaining physiological homeostasis across multiple bodily systems, notably the cardiovascular system. However, an increased Cu level in the body may cause blood vessel dysfunction and oxidative stress, which is unfavorable for the cardiovascular system. Middle-aged (7-8 months old) male Wistar rats (n/group = 12) received a diet supplemented with 6.45 mg Cu/kg (100% of the recommended daily dietary quantity of copper) for 8 weeks (Group A). The experimental group received 12.9 mg Cu/kg of diet (200%-Group B). An ex vivo study revealed that supplementation with 200% Cu decreased the contraction of isolated aortic rings to noradrenaline (0.7-fold) through FP receptor modulation. Vasodilation to sodium nitroprusside (1.10-fold) and acetylcholine (1.13-fold) was potentiated due to the increased net effect of prostacyclin derived from cyclooxygenase-1. Nitric oxide (NO, 2.08-fold), superoxide anion (O2•-, 1.5-fold), and hydrogen peroxide (H2O2, 2.33-fold) measured in the aortic rings increased. Blood serum antioxidant status (TAS, 1.6-fold), Cu (1.2-fold), Zn (1.1-fold), and the Cu/Zn ratio (1.4-fold) increased. An increase in Cu (1.12-fold) and the Cu/Zn ratio (1.09-fold) was also seen in the rats' livers. Meanwhile, cyclooxygenase-1 (0.7-fold), cyclooxygenase-2 (0.4-fold) and glyceraldehyde 3-phosphate dehydrogenase (0.5-fold) decreased. Moreover, a negative correlation between Cu and Zn was found (r = -0.80) in rat serum. Supplementation with 200% Cu did not modify the isolated heart functioning. No significant difference was found in the body weight, fat/lean body ratio, and organ weight for either the heart or liver, spleen, kidney, and brain. Neither Fe nor Se, the Cu/Se ratio, the Se/Zn ratio (in serum and liver), heme oxygenase-1 (HO-1), endothelial nitric oxide synthase (eNOS), or intercellular adhesion molecule-1 (iCAM-1) (in serum) were modified. Supplementation with 200% of Cu potentiated pro-oxidant status and modified vascular contractility in middle-aged rats.
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Affiliation(s)
- Klaudia Kitala-Tańska
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland;
| | - Katarzyna Socha
- Department of Bromatology, Medical University of Białystok, 15-222 Białystok, Poland;
| | - Jerzy Juśkiewicz
- Division of Food Science, Institute of Animal Reproduction and Food Research, Polish Academy of Sciences, 10-748 Olsztyn, Poland;
| | - Magdalena Krajewska-Włodarczyk
- Department of Mental and Psychosomatic Diseases, Faculty of Medicine, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland;
| | - Michał Majewski
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Warmia and Mazury in Olsztyn, 10-082 Olsztyn, Poland;
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3
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Chen Z, Liu X, Wu Y, Qi X, Ling Q, Wu Z, Shi Y, Hu H, Yu P, Ma J, Zhang J, Li P. Association between serum copper levels and stroke in the general population: A nationally representative study. J Stroke Cerebrovasc Dis 2024; 33:107473. [PMID: 37966096 DOI: 10.1016/j.jstrokecerebrovasdis.2023.107473] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/18/2023] [Accepted: 11/05/2023] [Indexed: 11/16/2023] Open
Abstract
OBJECTIVES The objective was to explore the association between serum copper levels and the prevalence of stroke. METHODS Data were obtained from 3 consecutive National Health and Nutrition Examination Survey (NHANES) cycles (2011-2016). Weighted multivariable logistic regression analysis was conducted to evaluate the association between serum copper levels and self-reported stroke. RESULTS A total of 5,151 adults met the inclusion criteria. A total of 181 (3.51%) stroke patients were identified. In comparison to individuals with serum copper levels in the lowest tertile (<16.4 µmol/l), those with levels in the middle tertile (16.4-19.8 µmol/l) had an odds ratio (OR) of 0.99 (95% confidence interval [CI]: 0.44-2.25), while those with levels in the highest tertile (>19.8 µmol/l) had an OR of 2.36 (95% CI: 1.01-5.52). Furthermore, each standard deviation (SD) increase in serum copper was found to be positively associated with the prevalence of stroke, with an OR of 1.44 (95% CI: 1.11-1.86). Dose‒response analysis showed a positive linear association between serum copper levels and stroke (Pnonlinearity=0.554). CONCLUSIONS This cross-sectional study suggested a positive association between serum copper levels and stroke among American adults.
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Affiliation(s)
- Zhiqiang Chen
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Xiao Liu
- Department of Cardiology, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, Guangdong 510080, China; Guangdong Province Key Laboratory of Arrhythmia and Electrophysiology, Guangzhou, Guangdong 510120, China
| | - Yifan Wu
- Department of Endocrinology Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Xinrui Qi
- Department of Endocrinology Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Qin Ling
- Department of Endocrinology Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Zuxiang Wu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Yumeng Shi
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Huan Hu
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Peng Yu
- Department of Endocrinology Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Jianyong Ma
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Jing Zhang
- Department of Anesthesiology, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China
| | - Ping Li
- Department of Cardiovascular Medicine, the Second Affiliated Hospital of Nanchang University, Nanchang 330006, China.
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Female Sexual Dysfunction in Subjects with Type 2 Diabetes Mellitus. SEXUALITY AND DISABILITY 2023. [DOI: 10.1007/s11195-023-09781-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
AbstractThe correlation of female sexual dysfunction (FSD) with the degree of glycemic control, the duration and complications of diabetic disease and cardiovascular risk factors are not so clear. The aim of this study was to assess the prevalence of FSD in a sample of females with type 2 diabetes mellitus (T2DM), and to identify factors involved in its pathogenesis. We enrolled 81 females who have T2DM. We administered the female sexual function index (FSFI), self-rating anxiety scale (SAS) and self-rating depression scale (SDS) questionnaires. We also estimated anthropometric parameters, glyco-metabolic control, comorbidities, autonomic nervous system assessment, some adipocytokines and ongoing therapy. 87% of participants were affected by FSD. There was evidence of an inverse correlation between the total score of the FSFI questionnaire and the mean of the values of HbA1c in the previous years. There was an inverse correlation with the duration of diabetes and homeostasis model assessment of insulin resistance index in participants not affected by FSD. Participants with FSD have a higher prevalence of anxiety (p = 0.043) and participants with depression and ischemic heart disease scored less on the FSFI questionnaire (p = 0.005 and p = 0.010, respectively). Homocysteine and E-selectin values were higher in participants with FSFI (p = 0.002, and p = 0.017, respectively). Most of the enrolled females with T2DM had FSD. Glycemic control, ischemic heart disease, endothelial dysfunction, autonomic neuropathy, and psychological conditions, such as anxiety and depression, seem to have a close correlation with FSD. An early diagnosis of FSD can help to improve not only participants’ quality of life, but also to early identify and treat risk factors related not only to FSD, but also to cardiovascular risk. Therefore, we highly recommend that clinicians have a high index of suspicion for FSD in females with T2DM.
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Shen Z, Zhang Z, Zhao W. Relationship between plasma homocysteine and chronic kidney disease in US patients with type 2 diabetes mellitus: a cross-sectional study. BMC Nephrol 2022; 23:419. [PMID: 36587192 PMCID: PMC9805683 DOI: 10.1186/s12882-022-03045-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 12/16/2022] [Indexed: 01/01/2023] Open
Abstract
AIMS This cross-sectional study aimed to investigate the association between plasma homocysteine (Hcy) and chronic kidney disease (CKD) in US patients with type 2 diabetes mellitus (T2DM). METHODS We used data from the 2003-2006 National Health and Nutritional Examination Surveys (NHANES). CKD was defined as an estimated glomerular filtration rate < 60 ml/min/1.73 m2 and/or urinary albumin-creatine ratio ≥ 3 mg/mmol. RESULTS This study included 1018 patients with T2DM. The mean Hcy value was 10.2 ± 4.6 μmol/L. Among the patients, 417 (40.96%) had hyperhomocysteinemia (HHcy) and 480 (47.15%) had CKD. The Hcy level was higher in patients with CKD than in those without CKD. Compared to patients with normal Hcy, those with HHcy were older and had worse renal function. After full multivariate adjustment, HHcy was positively associated with the risk of CKD in US patients with T2DM (OR, 1.17; 95% CI, 1.11-1.22; P < 0.001), which for women was 1.15 (95% CI, 1.08 ~ 1.23; P < 0.001) and for men was 1.18 (95% CI, 1.1 ~ 1.27; P < 0.001). CONCLUSIONS HHcy was independently associated with CKD in patients with T2DM. Further prospective studies are warranted to investigate the effect of Hcy on CKD in patients with T2DM.
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Affiliation(s)
- Zilong Shen
- grid.24696.3f0000 0004 0369 153XDepartment of Nephrology, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, 23 Art Museum Back Street, Dongcheng District, Beijing, 100010 China
| | - Zhengmei Zhang
- grid.24695.3c0000 0001 1431 9176Department of TCM Internal Medicine, Huguosi TCM Hospital, Affiliated with Beijing University of Chinese Medicine, Beijing, 100700 China
| | - Wenjing Zhao
- grid.24696.3f0000 0004 0369 153XDepartment of Nephrology, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, 23 Art Museum Back Street, Dongcheng District, Beijing, 100010 China
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Liu L, Duan H, Wang H, Miao J, Wu Z, Li C, Lu Y. Lysosome-Targeting Fluorescence Sensor for Sequential Detection and Imaging of Cu 2+ and Homocysteine in Living Cells. ACS OMEGA 2022; 7:34249-34257. [PMID: 36188316 PMCID: PMC9520687 DOI: 10.1021/acsomega.2c03691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
A conjugated polymer-based fluorescence sensor, namely, PTNPy, was constructed on the basis of a polythiophene scaffold coupled with dimethylpyridylamine (DPA) groups in side chains for the consecutive detection and quantification of Cu2+ and Hcy in a perfect aqueous medium. A dramatic fluorescence quenching of PTNPy by the addition of Cu2+ was observed in Tris-HCl buffer solution (2 mM, pH 7.4), demonstrating a quick (<1 min) and highly selective response to Cu2+ with a low limit of detection of 6.79 nM. Subsequently, the Cu2+-quenched fluorescence of PTNPy can be completely recovered by homocysteine (Hcy), showing excellent selectivity to Hcy over other competitive species such as cysteine and glutathione. Thanks to the low cytotoxicity and lysosomal targeting ability of PTNPy, it was further applied as an optical sensor for the sequential imaging of Cu2+ and Hcy in HeLa cells. More importantly, Hcy concentration was linearly related to the fluorescence intensity of PTNPy in living cells, demonstrating huge potential for real-time monitoring the fluctuation of Hcy levels in living cells.
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Affiliation(s)
- Lihua Liu
- School
of Materials Science & Engineering, Tianjin Key Laboratory for
Photoelectric Materials and Devices, Key Laboratory of Display Materials
& Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384, P. R. China
| | - Hongfei Duan
- School
of Materials Science & Engineering, Tianjin Key Laboratory for
Photoelectric Materials and Devices, Key Laboratory of Display Materials
& Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384, P. R. China
| | - Haohui Wang
- College
of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Jieru Miao
- School
of Materials Science & Engineering, Tianjin Key Laboratory for
Photoelectric Materials and Devices, Key Laboratory of Display Materials
& Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384, P. R. China
| | - Zhihui Wu
- School
of Materials Science & Engineering, Tianjin Key Laboratory for
Photoelectric Materials and Devices, Key Laboratory of Display Materials
& Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384, P. R. China
| | - Chenxi Li
- College
of Chemistry, Nankai University, Tianjin 300071, P. R. China
| | - Yan Lu
- School
of Materials Science & Engineering, Tianjin Key Laboratory for
Photoelectric Materials and Devices, Key Laboratory of Display Materials
& Photoelectric Devices, Ministry of Education, Tianjin University of Technology, Tianjin 300384, P. R. China
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7
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Xiao W, Ye P, Wang F, Cao R, Bai Y, Wang X. Plasma Homocysteine Is a Predictive Factor for Accelerated Renal Function Decline and Chronic Kidney Disease in a Community-Dwelling Population. Kidney Blood Press Res 2021; 46:541-549. [PMID: 34365457 DOI: 10.1159/000514360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/12/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Whether elevated plasma total homocysteine (tHcy) is a risk factor for the progression of kidney disease in general population has not been well established. The purpose of this study was to investigate the prognostic properties of plasma tHcy for renal function decrement and early chronic kidney disease (CKD) in community-dwelling populations with normal renal function at baseline. METHODS A total of 1,426 participants were enrolled and followed for a median of 4.8 years (interquartile range, 4.5-5.2), and estimated glomerular filtration rate (eGFR) was evaluated. One main outcome was the rapid eGFR decline defined as a decline in eGFR of >3 mL/min per 1.73 m2 per year; the other was the new incidence of CKD. RESULTS At the end of follow-up, the incidence of rapid eGFR decline and new-onset CKD was 20.7 and 5.6%, respectively. In multivariate linear regression analysis, age, central pulse pressure, fasting blood glucose, and concentration of tHcy were independent determinants of the change in eGFR. There was a graded association between tHcy quartiles and eGFR decline. Compared with participants with the lowest quartile of tHcy levels, those with the highest quartile had significantly increased risk for rapid eGFR decline (adjusted odds ratio [aOR] = 1.81; 95% confidence interval [CI]: 1.25-2.94) and new onset of CKD (adjusted hazard ratio = 4.29; 95% CI: 1.42-12.99) after adjusting for various confounders. Similarly, significant associations were also found when baseline tHcy was classified as hyperhomocysteinemia (>15 μmol/L) versus normal tHcy level (≤15 μmol/L). However, there was only association between the change in tHcy levels and new occurrence of CKD but not with rapid eGFR decline (aOR = 0.99, p = 0.613). CONCLUSIONS In this prospective cohort of individuals from community-based population, elevated plasma tHcy emerged as an independent predictor of renal function decline and incident CKD, which might support selection of at-risk individuals.
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Affiliation(s)
- Wenkai Xiao
- Department of Geriatric Cardiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Ping Ye
- Department of Geriatric Cardiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Fan Wang
- Department of Geriatric Cardiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Ruihua Cao
- Department of Geriatric Cardiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Yongyi Bai
- Department of Geriatric Cardiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Xiaona Wang
- Department of Geriatric Cardiology, Second Medical Center, Chinese PLA General Hospital, Beijing, China
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Chen ZN, Huang YR, Chen X, Liu K, Li SJ, Yang H, Chen W, Ren BQ, Luo ZH. Value of neutrophil-to-lymphocyte ratio as a marker of renal damage in patients with H-type hypertension. Biomark Med 2021; 15:637-646. [PMID: 34039027 DOI: 10.2217/bmm-2020-0638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: To explore the relationship between the neutrophil-to-lymphocyte ratio (NLR) and renal damage in patients with H-type hypertension. Materials & methods: A total of 618 patients between 2017 and 2019 were analyzed retrospectively. Results: NLR was significantly correlated with renal damage in hypertension patients. Appropriate cut-off value for NLR (2.247) was determined by receiver operating characteristic curve; linear regression analysis showed that NLR and estimated glomerular filtration rate, blood urea nitrogen/creatinine has a significant negative correlation in H-type hypertension group (p < 0.05); logistic regression analysis showed that the risk of renal damage increased by 10% for each 1 umol/l increase of homocysteine, and 51% for each 1.0 increase of NLR in H-type hypertension patients. Conclusion: NLR worth popularizing in prediction of renal damage in patients with H-type hypertension.
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Affiliation(s)
- Zhen-Ni Chen
- Department of Clinical Laboratory, TEDA International Cardiovascular Hospital, Cardiovascular Clinical College of Tianjin Medical University, Tianjin, China
| | - Yi-Ran Huang
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China
| | - Xing Chen
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Laboratory Medicine, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
| | - Kun Liu
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Medical Administration, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
| | - Si-Jin Li
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Laboratory Medicine, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
| | - Huan Yang
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Laboratory Medicine, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
| | - Wei Chen
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Laboratory Medicine, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
| | - Bi-Qiong Ren
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Laboratory Medicine, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
| | - Zhi-Hong Luo
- Hunan University of Traditional Chinese Medicine, Changsha, Hunan, China.,Department of Medical Administration, Hunan Provincial Second People's Hospital, Changsha, Hunan, China
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Shi W, Zhou Y, Wang H, Sun Y, Chen Y. Synergistic interaction of hypertension and hyperhomocysteinemia on chronic kidney disease: Findings from the National Health and Nutrition Examination Survey 1999‐2006. J Clin Hypertens (Greenwich) 2019; 21:1567-1577. [PMID: 31523928 DOI: 10.1111/jch.13673] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 06/22/2019] [Accepted: 07/08/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Wenrui Shi
- Department of Cardiology The First Hospital of China Medical University Shenyang China
| | - Yaping Zhou
- Department of Neurology The First Hospital of China Medical University Shenyang China
| | - Haoyu Wang
- Department of Cardiology Coronary Heart Disease Center, Fuwai Hospital National Center for Cardiovascular Diseases Chinese Academy of Medical Sciences & Peking Union Medical College Beijing China
| | - Yingxian Sun
- Department of Cardiology The First Hospital of China Medical University Shenyang China
| | - Yihan Chen
- Department of Cardiology The First Hospital of China Medical University Shenyang China
- Department of Cardiology, East Hospital Tongji University School of Medicine Shanghai China
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10
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Darroudi S, Saberi-Karimian M, Tayefi M, Tayefi B, Khashyarmanesh Z, Fereydouni N, Haghighi HM, Mahmoudi AA, Kharazmi-Khorassani J, Gonoodi K, Esmaeili H, Mohammadpour AH, Ferns GA, Ghayour-Mobarhan M. Association Between Hypertension in Healthy Participants and Zinc and Copper Status: a Population-Based Study. Biol Trace Elem Res 2019; 190:38-44. [PMID: 30267309 DOI: 10.1007/s12011-018-1518-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 09/09/2018] [Indexed: 11/30/2022]
Abstract
The prevalence of hypertension (HTN) is increasing globally. It has been shown that there is an association between micronutrient deficiency and HTN. In the current study, we aimed to assess the association between HTN with serum copper and zinc concentrations in a large representative Iranian population. The participants were enrolled into the Mashhad stroke and heart atherosclerotic disorders study (MASHAD study), a cohort study that was initiated in 2010. Anthropometric indices were assessed using standard procedures. Systolic (SBP) and diastolic (DBP) blood pressures were measured using a standard mercury sphygmomanometer. Fasting blood glucose (FBG), lipid profile, uric acid and blood urea nitrogen (BUN), and hs-CRP were measured using routine methods. HTN defined as persons who had SBP ≥ 130 mmHg and/or DBP ≥ 85 mmHg and/or medication use. Flame atomic absorption (Varian AA240FS) was used to measure serum Zn and Cu concentrations. SPSS software was used for all statistical analyses. A total of 9588 participants were recruited into the MASHAD study project. Participants were divided into two groups; 5695 healthy (non-hypertensive) (mean age 45.85 ± 7.5 years) and 3893 hypertensive participants (mean age 51.18 ± 7.67 years). Systolic (p < 0.001) and diastolic blood pressure (p < 0.001) were significantly different for different serum copper quartiles. The participants with serum copper levels < 80 μg/dl had 1.33 times greater risk of an increased blood pressure than other participants. Participants with serum copper levels > 130 μg/dl had a 1.94-fold higher risk of raised blood pressure. Serum zinc was not associated with systolic blood pressure, but individuals in the first quartile level of serum zinc had a diastolic blood pressure that was significantly higher than other quartiles (p = 0.035). Serum copper is associated with blood pressure status in adults in a U-shaped relationship, with a range of serum copper between 80 and 130 μg/dl being associated with normal blood pressure.
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Affiliation(s)
- Susan Darroudi
- Molecular Medicine Group, Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Saberi-Karimian
- Molecular Medicine Group, Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Tayefi
- Department of Cardiovascular, Imam Reza Hospital, Mashhad University of Medical Science (MUMS), Mashhad, Iran
- University international Accreditation, International Office, Clinical Research Unit, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Batool Tayefi
- Preventive Medicine and Public Health Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Khashyarmanesh
- Department of Medicinal Chemistry, School of Pharmacology, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Narges Fereydouni
- Molecular Medicine Group, Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamideh Moalemzadeh Haghighi
- Department of Medicinal Chemistry, School of Pharmacology, Mashhad University of Medical Sciences, Mashhad, Iran
| | | | - Jasmine Kharazmi-Khorassani
- Molecular Medicine Group, Department of Modern Sciences and Technologies, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Kayhan Gonoodi
- Department of Nutrition, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Habibolah Esmaeili
- Department of Biostatistics, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir Hooshang Mohammadpour
- Department of Clinical Pharmacy, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
- Pharmaceutical Research Center, Pharmaceutical Institute of Technology, Mashhad University of Medical Sciences, P.O. Box 91775-1365, Mashhad, Iran.
| | - Gordon A Ferns
- Division of Medical Education, Brighton & Sussex Medical School, Falmer, Brighton, Sussex, BN1 9PH, UK
| | - Majid Ghayour-Mobarhan
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
- Biochemistry of Nutrition Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, 99199-91766, Iran.
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11
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Acute Exposure to Indoxyl Sulfate Impairs Endothelium-Dependent Vasorelaxation in Rat Aorta. Int J Mol Sci 2019; 20:ijms20020338. [PMID: 30650577 PMCID: PMC6359309 DOI: 10.3390/ijms20020338] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 01/10/2019] [Accepted: 01/12/2019] [Indexed: 12/20/2022] Open
Abstract
Gut microbiota are emerging as potential contributors to the regulation of host homeostasis. Dysbiosis of the gut microbiota associated with increased intestinal permeability facilitates the passage of endotoxins and other microbial products, including indoxyl sulfate in the circulation. Although an emerging body of evidence has suggested that indoxyl sulfate is a key substance for the development of chronic kidney disease, few studies have investigated the direct association of indoxyl sulfate with vascular function. We hypothesized that indoxyl sulfate adversely affects vascular function. Aortas isolated from male Wistar rat were examined in the presence or absence of indoxyl sulfate to assess the vascular function, including vasorelaxation and vasocontraction. Indoxyl sulfate (vs. vehicle) (1) decreased vasorelaxation induced by acetylcholine (ACh) but not by sodium nitroprusside; (2) had no significant alterations of noradrenaline-induced vasocontraction in the absence and presence of endothelium; (3) decreased adenylyl cyclase activator (forskolin)-induced vasorelaxation, while such a difference was eliminated by endothelial denudation; and (4) decreased vasorelaxations induced by calcium ionophore (A23187) and transient receptor potential vanilloid 4 agonist (GSK1016790A). The indoxyl sulfate-induced decrease in the vasorelaxations induced by ACh and A23187 increased by cell-permeant superoxide dismutase or by organic anion transporter inhibitor. However, apocynin, an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, had no effects on vasorelaxations induced by ACh, A23187, forskolin, and GSK1016790A in the presence of indoxyl sulfate. These results suggest that indoxyl sulfate directly affects the vascular function, particularly, endothelium-dependent vasorelaxation, and this effect may be attributable to increased oxidative stress after cell transportion via organic anion transporter, and such increased oxidative stress may not be attributable to activation of NADPH oxidase activation.
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Zhang Z, Zhu LL, Jiang HS, Chen H, Chen Y, Dai YT. Demethylation treatment restores erectile function in a rat model of hyperhomocysteinemia. Asian J Androl 2017; 18:763-8. [PMID: 26585696 PMCID: PMC5000801 DOI: 10.4103/1008-682x.163271] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Methylation modification is an important cellular mechanism of gene expression regulation. Dimethylarginine dimethylaminohydrolase-2 (DDAH-2) protein is a pivotal molecular for endothelium function. To explore the effects of 5-aza-deoxycytidine (5-aza), a demethylation agent, in hyperhomocysteinemia (hhcy)-related erectile dysfunction (ED) rats, 5-aza (1 mg kg−1) was administrated to Sprague-Dawley hhcy-rats induced by supplemented methionine chow diet. Erectile function, nitric oxide-cyclic guanosine monophosphate (NO-cGMP) levels, expression of DDAH-2 protein and promoter methylation status of DDAH-2 were studied in the corpora cavernosa. We found that supplemented methionine diet induced a high homocysteine level after 6 weeks of treatment. DDAH-2 protein was down-regulated in the corpora cavernosa while the administration of 5-aza up-regulated DDAH-2 expression and restored erectile function. The methionine-fed rats showed high methylation levels of DDAH-2 promoter region while the group treated with 5-aza demonstrated lower-methylation levels when compared to the methionine-fed group. Besides, the administration of 5-aza improved NO and cGMP levels in methionine-fed rats. Therefore, the methylation mechanism involves in ED pathogenesis, and demethylation offers a potential new strategy for ED treatment.
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Affiliation(s)
- Zheng Zhang
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Lei-Lei Zhu
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - He-Song Jiang
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Hai Chen
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Yun Chen
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
| | - Yu-Tian Dai
- Department of Andrology, Affiliated Drum Tower Hospital, School of Medicine, Nanjing University, Nanjing, China
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Tyagi SC, Rodriguez W, Patel AM, Roberts AM, Falcone JC, Passmore JC, Fleming JT, Joshua IG. Hyperhomocysteinemic Diabetic Cardiomyopathy: Oxidative Stress, Remodeling, and Endothelial-Myocyte Uncoupling. J Cardiovasc Pharmacol Ther 2016; 10:1-10. [PMID: 15821833 DOI: 10.1177/107424840501000101] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Accumulation of oxidized-matrix (fibrosis) between the endothelium (the endothelial cells embedded among the myocytes) and cardiomyocytes is a hallmark of diabetes mellitus and causes diastolic impairment. In diabetes mellitus, elevated levels of homocysteine activate matrix metalloproteinase and disconnect the endothelium from myocytes. Extracellular matrix functionally links the endothelium to the cardiomyocyte and is important for their synchronization. However, in diabetes mellitus, a disconnection is caused by activated metalloproteinase, with subsequent accumulation of oxidized matrix between the endothelium and myocyte. This contributes to endothelial-myocyte uncoupling and leads to impaired diastolic relaxation of the heart in diabetes mellitus. Elevated levels of homocysteine in diabetes are attributed to impaired homocysteine metabolism by glucose and insulin and decreased renal clearance. Homocysteine induces oxidative stress and is inversely related to the expression of peroxisome proliferators activated receptor (PPAR). Several lines of evidence suggest that ablation of the matrix metalloproteinase (MMP-9) gene ameliorates the endothelial-myocyte uncoupling in diabetes mellitus. Homocysteine competes for, and decreases the PPARγ activity. In diabetes mellitus, endothelial-myocyte uncoupling is associated with matrix metalloproteinase activation and decreased PPARγ activity. The purpose of this review is to discuss the role of endothelial-myocyte uncoupling in diabetes mellitus and increased levels of homocysteine, causing activation of latent metalloproteinases, decreased levels of thioredoxin and peroxiredoxin, and cardiac tissue inhibitor of metalloproteinase (CIMP) in response to antagonizing PPARγ.
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Affiliation(s)
- Suresh C Tyagi
- Department of Physiology and Biophysics, University of Louisville School of Medicine, Louisville, KY 40202, USA.
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Cheung CCH, Soon CY, Chuang CL, Phillips ARJ, Zhang S, Cooper GJS. Low-dose copper infusion into the coronary circulation induces acute heart failure in diabetic rats: New mechanism of heart disease. Biochem Pharmacol 2015. [PMID: 26208785 DOI: 10.1016/j.bcp.2015.06.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Diabetes impairs copper (Cu) regulation, causing elevated serum Cu and urinary Cu excretion in patients with established cardiovascular disease; it also causes cardiomyopathy and chronic cardiac impairment linked to defective Cu homeostasis in rats. However, the mechanisms that link impaired Cu regulation to cardiac dysfunction in diabetes are incompletely understood. Chronic treatment with triethylenetetramine (TETA), a Cu²⁺-selective chelator, improves cardiac function in diabetic patients, and in rats with heart disease; the latter displayed ∼3-fold elevations in free Cu²⁺ in the coronary effluent when TETA was infused into their coronary arteries. To further study the nature of defective cardiac Cu regulation in diabetes, we employed an isolated-perfused, working-heart model in which we infused micromolar doses of Cu²⁺ into the coronary arteries and measured acute effects on cardiac function in diabetic and non-diabetic-control rats. Infusion of CuCl₂ solutions caused acute dose-dependent cardiac dysfunction in normal hearts. Several measures of baseline cardiac function were impaired in diabetic hearts, and these defects were exacerbated by low-micromolar Cu²⁺ infusion. The response to infused Cu²⁺ was augmented in diabetic hearts, which became defective at lower infusion levels and underwent complete pump failure (cardiac output = 0 ml/min) more often (P < 0.0001) at concentrations that only moderately impaired function of control hearts. To our knowledge, this is the first report describing the acute effects on cardiac function of pathophysiological elevations in coronary Cu²⁺. The effects of Cu²⁺ infusion occur within minutes in both control and diabetic hearts, which suggests that they are not due to remodelling. Heightened sensitivity to the acute effects of small elevations in Cu²⁺ could contribute substantively to impaired cardiac function in patients with diabetes and is thus identified as a new mechanism of heart disease.
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Affiliation(s)
- Carlos Chun Ho Cheung
- The School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Choong Yee Soon
- The School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Chia-Lin Chuang
- The School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Anthony R J Phillips
- The School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand
| | - Shaoping Zhang
- The School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand; The Maurice Wilkins Centre for Molecular BioDiscovery, Faculty of Science, The University of Auckland, Auckland, New Zealand
| | - Garth J S Cooper
- The School of Biological Sciences, Faculty of Science, University of Auckland, Auckland, New Zealand; The Maurice Wilkins Centre for Molecular BioDiscovery, Faculty of Science, The University of Auckland, Auckland, New Zealand; Department of Pharmacology, Medical Sciences Division, University of Oxford, Oxford, UK; The Centre for Advanced Discovery and Experimental Therapeutics, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, The University of Manchester, Manchester, UK; The Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK.
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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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Levi A, Cohen E, Levi M, Goldberg E, Garty M, Krause I. Elevated serum homocysteine is a predictor of accelerated decline in renal function and chronic kidney disease: A historical prospective study. Eur J Intern Med 2014; 25:951-5. [PMID: 25457436 DOI: 10.1016/j.ejim.2014.10.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/12/2014] [Accepted: 10/14/2014] [Indexed: 01/01/2023]
Abstract
OBJECTIVE To estimate the effect of elevated serum homocysteine level on renal function decline and on the incidence of chronic kidney disease (CKD) in the general population. METHODS A historical prospective study on 3602 subjects attending a screening center in Israel between the years 2000 and 2012. Only subjects with normal estimated glomerular filtration rate (eGFR) and without proteinuria were included. Subjects were divided to two groups according to mean total serum homocysteine level (≤ 15, >15μmol/l). Linear mixed effect model was used to estimate the annual eGRF decline in respect to homocysteine group. Cox proportional hazards models were used to estimate hazard ratios for CKD in the normal compared to the elevated homocysteine group. RESULTS Annual eGFR decline was 25% higher in subjects with elevated versus normal mean homocysteine level (0.90 ± 0.16 ml/min/1.37 m(2) vs. 0.72 ± 0.14 ml/min/1.37 m(2), p<0.001). In a median follow up of 7.75 years, 38 subjects developed CKD (1.05%). Elevated mean homocysteine level was highly associated with developing CKD (HR 4.85, 95% CI 2.48-9.49, p<0.001). In a multivariate analysis which adjusted for age, baseline kidney function, HDL cholesterol, BMI, vitamin B12 and folic acid levels, these relationships remained substantially unchanged. CONCLUSIONS Elevated mean serum homocysteine level is associated with an accelerated decline in renal function in both men and women, and is an independent risk factor for the development of CKD in the general population. Further prospective randomized clinical trials are needed to clarify whether the reduction in serum homocysteine concentrations will result in an improved renal prognosis.
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Affiliation(s)
- Amos Levi
- Department of Internal Medicine F - Recanati, Rabin Medical Center, Beilinson Hospital, Petah-Tiqva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eytan Cohen
- Department of Internal Medicine F - Recanati, Rabin Medical Center, Beilinson Hospital, Petah-Tiqva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Micha Levi
- Novartis Pharmaceutical Corp., East Hanover NJ, USA
| | - Elad Goldberg
- Department of Internal Medicine F - Recanati, Rabin Medical Center, Beilinson Hospital, Petah-Tiqva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Moshe Garty
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Recanati Institute for Preventive Medicine, Rabin Medical Center, Petah-Tiqva, Israel
| | - Ilan Krause
- Department of Internal Medicine F - Recanati, Rabin Medical Center, Beilinson Hospital, Petah-Tiqva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Chen JY, Tsai YW, Chen SY, Ho CI, Weng YM, Hsiao CT, Li WC. The association of leptin and homocysteine with renal function impairment in a population of Taiwanese adults. Clin Nutr 2014; 34:943-50. [PMID: 25453393 DOI: 10.1016/j.clnu.2014.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 09/08/2014] [Accepted: 10/01/2014] [Indexed: 11/18/2022]
Abstract
BACKGROUND & AIMS Higher levels of leptin and homocysteine (Hcy) have been evaluated as risk factors of chronic kidney disease in patients and general population. The aim of this study was to examine gender differences in the associations of leptin and Hcy levels and renal function a representative healthy young population in Taiwan. METHODS The participants aged ≥18 years who underwent health examinations were included and categorized into three groups by gender-specific tertiles of leptin and Hcy levels. Estimated glomerular filtration rates (eGFR) were estimated according to the modified equation of Modification of Diet in Renal Disease (MDRD). RESULTS A higher mean Hcy level was found in male subjects than females. Mean values of metabolic syndrome risk factors significantly elevated with increasing leptin levels in both genders. Both male and female subjects with higher plasma Hcy levels were more likely to have a lower eGFR. Plasma Hcy levels were significantly negatively correlated with eGFR in linear regression models adjusted for age and smoking. The associations persisted even after mean arterial pressure and fasting plasma glucose were included for adjustments both genders. Plasma Hcy level was negatively associated eGFR and the association was more profound for females. CONCLUSIONS Leptin levels did not reveal strong or consistent evidence to support a significant association with eGFR. Hcy had a more decisive effect on renal function impairment than leptin and may be considered a more sensitive biomarker for Taiwanese adults.
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Affiliation(s)
- Jau-Yuan Chen
- Department of Family Medicine, Chang Gung Memorial Hospital at Linkou, Taiwan
| | - Yi-Wen Tsai
- Department of Family Medicine, Chang Gung Memorial Hospital at Linkou, Taiwan
| | - Shou-Yen Chen
- Department of Emergency Medicine, Chang Gung Memorial Hospital at Linkou, Taiwan
| | - Chih-I Ho
- Department of Family Medicine, Chang Gung Memorial Hospital at Linkou, Taiwan
| | - Yi-Ming Weng
- Department of Emergency Medicine, Chang Gung Memorial Hospital at Linkou, Taiwan
| | - Cheng-Ting Hsiao
- Department of Emergency Medicine, Chang Gung Memorial Hospital at Chiayi, Taiwan; Chang Gung Institute of Technology, Chiayi Branch, Taiwan
| | - Wen-Cheng Li
- Department of Occupation Medicine, Chang-Gung Memorial Hospital at Chiayi, Taiwan.
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Jeremy JY, Shukla N. Ceruloplasmin dysfunction: a key factor in the pathophysiology of atrial fibrillation? J Intern Med 2014; 275:191-4. [PMID: 24188106 DOI: 10.1111/joim.12156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- J Y Jeremy
- NIHR Bristol Biomedical Research Unit, Bristol Heart Institute, University of Bristol, Bristol, UK
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Gaikwad NW. Mass spectrometry evidence for formation of estrogen-homocysteine conjugates: estrogens can regulate homocysteine levels. Free Radic Biol Med 2013; 65:1447-1454. [PMID: 23928335 DOI: 10.1016/j.freeradbiomed.2013.07.041] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/09/2013] [Accepted: 07/26/2013] [Indexed: 12/17/2022]
Abstract
Homocysteine (HCys), a sulfur-containing amino acid, is formed during the metabolism of methionine. An imbalance between the rate of production and the use of HCys during methionine metabolism can result in an increase in the plasma and urinary levels of HCys. HCys has been shown to be toxic to vascular endothelial cells through several pathways. Many earlier clinical studies have revealed an association between plasma HCys and cardiovascular and other diseases. In contrast, estrogens are suggested to lower the risk of cardiovascular disease. Several studies indicate that estrogen metabolites could be responsible for cardiovascular protection. It has been demonstrated that electrophilic estrogen quinones, E1(E2)-2,3-Q and E1(E2)-3,4-Q, can alkylate DNA as well as form conjugates with glutathione. I hypothesize that estrogen quinones generated in situ by oxidative enzymes, metal ions, or molecular oxygen can interact with HCys to form conjugates. This in turn could lower the levels of toxic HCys as well as quenching the reactive estrogen quinones, resulting in cardiovascular protective effects. To test the feasibility of a protective estrogen-HCys pathway, estrogen quinones were treated with HCys. Tandem mass spectrometry analysis of the assay mixture shows the formation of estrogen-HCys conjugates. Furthermore, incubation of catechol estrogens with myeloperoxidase (MPO) in the presence of HCys resulted in the formation of respective estrogen-HCys conjugates. The identities of estrogen-HCys conjugates in MPO assay extracts were confirmed by comparing them to pure synthesized estrogen-HCys standards. I propose that through conjugation estrogens could chemically regulate HCys levels; moreover these conjugates could be used as potential biomarkers in determining health.
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Affiliation(s)
- Nilesh W Gaikwad
- Department of Nutrition and Department of Environmental Toxicology, University of California at Davis, Davis, CA 95616, USA.
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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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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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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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Sindler AL, Reyes R, Chen B, Ghosh P, Gurovich AN, Kang LS, Cardounel AJ, Delp MD, Muller-Delp JM. Age and exercise training alter signaling through reactive oxygen species in the endothelium of skeletal muscle arterioles. J Appl Physiol (1985) 2013; 114:681-93. [PMID: 23288555 DOI: 10.1152/japplphysiol.00341.2012] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exercise training ameliorates age-related impairments in endothelium-dependent vasodilation in skeletal muscle arterioles. Additionally, exercise training is associated with increased superoxide production. The purpose of this study was to determine the role of superoxide and superoxide-derived reactive oxygen species (ROS) signaling in mediating endothelium-dependent vasodilation of soleus muscle resistance arterioles from young and old, sedentary and exercise-trained rats. Young (3 mo) and old (22 mo) male rats were either exercise trained or remained sedentary for 10 wk. To determine the impact of ROS signaling on endothelium-dependent vasodilation, responses to acetylcholine were studied under control conditions and during the scavenging of superoxide and/or hydrogen peroxide. To determine the impact of NADPH oxidase-derived ROS, endothelium-dependent vasodilation was determined following NADPH oxidase inhibition. Reactivity to superoxide and hydrogen peroxide was also determined. Tempol, a scavenger of superoxide, and inhibitors of NADPH oxidase reduced endothelium-dependent vasodilation in all groups. Similarly, treatment with catalase and simultaneous treatment with tempol and catalase reduced endothelium-dependent vasodilation in all groups. Decomposition of peroxynitrite also reduced endothelium-dependent vasodilation. Aging had no effect on arteriolar protein content of SOD-1, catalase, or glutathione peroxidase-1; however, exercise training increased protein content of SOD-1 in young and old rats, catalase in young rats, and glutathione peroxidase-1 in old rats. These data indicate that ROS signaling is necessary for endothelium-dependent vasodilation in soleus muscle arterioles, and that exercise training-induced enhancement of endothelial function occurs, in part, through an increase in ROS signaling.
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Affiliation(s)
- Amy L Sindler
- Department of Physiology and Pharmacology, and the Center for Interdisciplinary Research in Cardiovascular Sciences, West Virginia University School of Medicine, Morgantown, West Virginia, USA
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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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Kang LS, Chen B, Reyes RA, Leblanc AJ, Teng B, Mustafa SJ, Muller-Delp JM. Aging and estrogen alter endothelial reactivity to reactive oxygen species in coronary arterioles. Am J Physiol Heart Circ Physiol 2011; 300:H2105-15. [PMID: 21441309 DOI: 10.1152/ajpheart.00349.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Endothelium-dependent, nitric oxide (NO)-mediated vasodilation can be impaired by reactive oxygen species (ROS), and this deleterious effect of ROS on NO availability may increase with aging. Endothelial function declines rapidly after menopause, possibly because of loss of circulating estrogen and its antioxidant effects. The purpose of the current study was to determine the role of O(2)(-) and H(2)O(2) in regulating flow-induced dilation in coronary arterioles of young (6-mo) and aged (24-mo) intact, ovariectomized (OVX), or OVX + estrogen-treated (OVE) female Fischer 344 rats. Both aging and OVX reduced flow-induced NO production, whereas flow-induced H(2)O(2) production was not altered by age or estrogen status. Flow-induced vasodilation was evaluated before and after treatment with the superoxide dismutase (SOD) mimetic Tempol (100 μM) or the H(2)O(2) scavenger catalase (100 U/ml). Removal of H(2)O(2) with catalase reduced flow-induced dilation in all groups, whereas Tempol diminished vasodilation in intact and OVE, but not OVX, rats. Immunoblot analysis revealed elevated nitrotyrosine with aging and OVX. In young rats, OVX reduced SOD protein while OVE increased SOD in aged rats; catalase protein did not differ in any group. Collectively, these studies suggest that O(2)(-) and H(2)O(2) are critical components of flow-induced vasodilation in coronary arterioles from female rats; however, a chronic deficiency of O(2)(-) buffering by SOD contributes to impaired flow-induced dilation with aging and loss of estrogen. Furthermore, these data indicate that estrogen replacement restores O(2)(-) homeostasis and flow-induced dilation of coronary arterioles, even at an advanced age.
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Affiliation(s)
- Lori S Kang
- Dept. of Physiology and Functional Genomics, Univ. of Florida, 1600 SW Archer Rd., P.O. Box 100274, Gainesville, FL 32610, USA
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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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Affiliation(s)
- George J. Brewer
- Departments of Human Genetics and Internal Medicine, University of Michigan Medical School,Ann Arbor, Michigan
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Sindler AL, Delp MD, Reyes R, Wu G, Muller-Delp JM. Effects of ageing and exercise training on eNOS uncoupling in skeletal muscle resistance arterioles. J Physiol 2009; 587:3885-97. [PMID: 19528246 PMCID: PMC2746616 DOI: 10.1113/jphysiol.2009.172221] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 06/14/2009] [Indexed: 01/03/2023] Open
Abstract
Reduced availability of tetrahydrobiopterin (BH(4)) contributes to the age-related decline of nitric oxide (NO)-mediated vasodilatation of soleus muscle arterioles. Depending on availability of substrate and/or necessary co-factors, endothelial nitric oxide synthase (eNOS) can generate NO and/or superoxide (O(2)(-)). We evaluated the effects of age and chronic exercise on flow-induced vasodilatation and levels of NO and O(2)(-) in soleus muscle arterioles. Young (3 months) and old (22 months) male rats were exercise trained or remained sedentary (SED) for 10 weeks. Flow-stimulated NO and O(2)(-), as well as BH(4) and l-arginine content, were determined in soleus muscle arterioles. Flow-induced vasodilatation was assessed under control conditions and during the blockade of O(2)(-) and/or hydrogen peroxide. Exercise training enhanced flow-induced vasodilatation in arterioles from young and old rats. Old age reduced, and exercise training restored, BH(4) content and flow-stimulated NO availability. Flow-stimulated, eNOS-derived O(2)(-) levels were higher in arterioles from old SED compared to those from young SED rats. Exercise training increased flow-stimulated eNOS-derived O(2)(-) levels in arterioles from young but not old rats. O(2)(-) scavenging with Tempol reduced flow-induced vasodilatation from all groups except young SED rats. Addition of catalase to Tempol-treated arterioles eliminated flow-induced vasodilatation in arterioles from all groups. Catalase reduced flow-induced vasodilatation from all groups. In Tempol-treated arterioles, flow-induced vasodilatation was restored by deferoxamine, an iron chelator. These data indicate that uncoupling of eNOS contributes to the age-related decline in flow-induced vasodilatation; however, reactive oxygen species are required for flow-induced vasodilatation in soleus muscle arterioles from young and old rats.
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Affiliation(s)
- Amy L Sindler
- Department of Physiology and Pharmacology, West Virginia University, School of Medicine, Morgantown, WV 26506, USA
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Kang LS, Reyes RA, Muller-Delp JM. Aging impairs flow-induced dilation in coronary arterioles: role of NO and H(2)O(2). Am J Physiol Heart Circ Physiol 2009; 297:H1087-95. [PMID: 19617414 DOI: 10.1152/ajpheart.00356.2009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aging contributes significantly to the development of cardiovascular disease and is associated with elevated production of reactive oxygen species (ROS). The beneficial effects of nitric oxide (NO)-mediated vasodilation are quickly abolished in the presence of ROS, and this effect may be augmented with aging. We previously demonstrated an age-induced impairment of flow-induced dilation in rat coronary arterioles. Therefore, the purpose of this study was to determine the effects of O(2)(-) scavenging, as well as removal of H(2)O(2), the byproduct of O(2)(-) scavenging, on flow-mediated dilation in coronary resistance arterioles of young (4 mo) and old (24 mo) male Fischer 344 rats. Flow increased NO and H(2)O(2) production as evidenced by enhanced diaminofluorescein and dichlorodihydrofluorescein fluorescence, respectively, whereas aging reduced flow-induced NO and H(2)O(2) production. Endothelium-dependent vasodilation was evaluated by increasing intraluminal flow (5-60 nl/s) before and after treatment with the superoxide dismutase mimetic Tempol (100 muM), the H(2)O(2) scavenger catalase (100 U/ml), or Tempol plus catalase. Catalase reduced flow-induced dilation in both groups, whereas Tempol and Tempol plus catalase diminished vasodilation in young but not old rats. Tempol plus deferoxamine (100 muM), an inhibitor of hydroxyl radical formation, reversed Tempol-mediated impairment of flow-induced vasodilation in young rats and improved flow-induced vasodilation in old rats compared with control. Immunoblot analysis revealed increases in endogenous superoxide dismutase, catalase, and nitrotyrosine protein levels with aging. Collectively, these data indicate that NO- and H(2)O(2)-mediated flow-induced signaling decline with age in coronary arterioles and that elevated hydroxyl radical formation contributes to the age-related impairment of flow-induced vasodilation.
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Affiliation(s)
- Lori S Kang
- Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, West Virginia, USA
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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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Abstract
Elevated levels of homocysteine (Hcy) (known as hyperhomocysteinemia HHcy) are involved in dilated cardiomyopathy. Hcy chelates copper and impairs copper-dependent enzymes. Copper deficiency has been linked to cardiovascular disease. We tested the hypothesis that copper supplement regresses left ventricular hypertrophy (LVH), fibrosis and endothelial dysfunction in pressure overload DCM mice hearts. The mice were grouped as sham, sham + Cu, aortic constriction (AC), and AC + Cu. Aortic constriction was performed by transverse aortic constriction. The mice were treated with or without 20 mg/kg copper supplement in the diet for 12 weeks. The cardiac function was assessed by echocardiography and electrocardiography. The matrix remodeling was assessed by measuring matrix metalloproteinase (MMP), tissue inhibitor of metalloproteinases (TIMPs), and lysyl oxidase (LOX) by Western blot analyses. The results suggest that in AC mice, cardiac function was improved with copper supplement. TIMP-1 levels decreased in AC and were normalized in AC + Cu. Although MMP-9, TIMP-3, and LOX activity increased in AC and returned to baseline value in AC + Cu, copper supplement showed no significant effect on TIMP-4 activity after pressure overload. In conclusion, our data suggest that copper supplement helps improve cardiac function in a pressure overload dilated cardiomyopathic heart.
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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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Hansrani M, Stansby G. The use of an in vivo model to study the effects of hyperhomocysteinaemia on vascular function. J Surg Res 2007; 145:13-8. [PMID: 17644114 DOI: 10.1016/j.jss.2007.02.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2006] [Revised: 02/08/2007] [Accepted: 02/11/2007] [Indexed: 11/13/2022]
Abstract
BACKGROUND/AIMS To use an in vivo rat model of hyperhomocysteinaemia (HHCy) to study its impact on vascular function. METHODS Twenty rats were fed either a control or HHCy-inducing diet for 10 wk. The response of aortic rings to contraction with phenylephrine, and relaxation to acetylcholine (endothelium-dependant relaxation) or sodium nitroprusside (endothelium-independent relaxation) was analyzed. The results were compared using an analysis of variance (ANOVA). RESULTS There was a significant elevation of HCy in the treated group (20.5 versus 1.6 micromol/L, P = 0.004). There was no significant difference between the two groups in blood pressure measurements (ANOVA, P = 0.152). In a dose-dependant manner, phenylephrine elicited significantly greater contraction in aorta taken from HHCy rats than that taken from controls (ANOVA, P < 0.001), acetylcholine elicited significantly less percentage relaxation in aorta taken from HHCy rats than from controls (ANOVA, P = 0.003) and though sodium nitroprusside stimulated less percentage relaxation in aorta taken from HHCy rats than controls, this did not reach significance (ANOVA, P = 0.051). CONCLUSIONS In diet induced hyperhomocysteinaemic rats, there is enhanced vascular contraction in response to phenylephrine and impaired endothelium-dependant relaxation in response to acetylcholine.
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Affiliation(s)
- Monica Hansrani
- Northern Vascular Unit, Freeman Hospital, Newcastle upon Tyne, United Kingdom
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Shukla N, Angelini GD, Jeremy JY. Interactive Effects of Homocysteine and Copper on Angiogenesis in Porcine Isolated Saphenous Vein. Ann Thorac Surg 2007; 84:43-9. [PMID: 17588380 DOI: 10.1016/j.athoracsur.2007.03.087] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 03/28/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND After coronary artery bypass grafting procedures with saphenous vein, there is a protracted elevation of plasma homocysteine and copper. These interact to elicit endothelial dysfunction through promotion of superoxide. It has been suggested that angiogenesis and the formation of a neovasa vasorum is important in mediating vein graft patency. A novel in vitro model of angiogenesis in isolated pig saphenous veins was therefore developed to study the effect of homocysteine and copper and the role of superoxide on tubule growth, an index of angiogenesis. METHODS Two-millimeter rings of porcine saphenous veins were embedded in fibrin, incubated for 2 weeks with homocysteine and copper chloride, and tubules counted. RESULTS Tubule growth in cultured saphenous veins, which was inhibited by angiostatin, occurred in a time-dependent manner during a 14-day period. Copper chloride alone at 1 microM and 10 microM augmented microtubule formation, whereas homocysteine alone at up to 1 mM had no effect. Homocysteine and copper chloride together markedly inhibited microtubule formation. Significant inhibition of tubule formation and superoxide formation was elicited with inhibitors of nicotinamide adenine dinucleotide phosphate oxidase, mitochondrial respiration, and xanthine oxidase. Copper chloride augmented superoxide formation, but homocysteine had no effect. Homocysteine and copper chloride together also augmented superoxide formation. CONCLUSIONS These data indicate that the increase in plasma homocysteine and copper may exert a deleterious effect on graft patency by preventing the formation of a neovasa vasorum, thereby promoting hypoxia. This effect is mediated by a mechanism independent of superoxide which actually promotes angiogenesis in this model.
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Affiliation(s)
- Nilima Shukla
- Bristol Heart Institute, University of Bristol, Bristol, United Kingdom
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Zhang BQ, Hu SJ, Qiu LH, Zhu JH, Xie XJ, Sun J, Zhu ZH, Xia Q, Bian K. Effects of Astragalus membranaceus and its main components on the acute phase endothelial dysfunction induced by homocysteine. Vascul Pharmacol 2006; 46:278-85. [PMID: 17196887 DOI: 10.1016/j.vph.2006.11.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 10/14/2006] [Accepted: 11/02/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVE This study was designed to investigate the effects of Astragalus membranaceus (AM) and its main components, astragalus saponin (ASP), astragalus polysaccharide (APS) and aminobutyric acid (GABA), on homocysteine (Hcy) induced acute impairment of vascular tone and to explore whether the antioxidant mechanism was involved in AM protective effect. METHODS Inhibitory effects of Hcy and protective effects of AM and its main components on endothelium-dependent relaxation of aortic rings were determined by isometric tension recordings and nitric oxide signaling was assayed with 125I-cGMP RIA Kit. Furthermore, generation of reactive oxygen species (ROS) in endothelial cells was detected using 5-(6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (CM-H2DCF-DA). RESULTS Hcy significantly inhibited endothelium-dependent relaxation to acetylcholine (ACh) in a dose-dependent manner, and decreased cGMP levels increased by ACh in aorta. Furthermore, superoxide dismutase (SOD), AM, and ASP markedly attenuated inhibition of vasorelaxation and downregulation of cGMP level by Hcy, and APS exerted a tendency to reverse both of the depressive responses, while GABA had no similar effects. Additionally, partially impaired relaxation by Hcy was completely blocked due to the presence of N(omega)-nitro-L-arginine-methyl ester (L-NAME), which could not be further altered by treatment with AM, ASP, APS or GABA. Finally, Hcy significantly increased intracellular ROS levels in endothelial cells as measured by CM-H2DCF-DA fluorescence. SOD, AM, ASP, and APS, but not GABA, inhibited Hcy-stimulated ROS generation. CONCLUSION This study demonstrated that AM and ASP, potently protected endothelium-dependent relaxation against the acute injury from Hcy through nitric oxide regulatory pathways, in which antioxidation played a key role.
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Affiliation(s)
- Bi-Qi Zhang
- Department of Cardiology, The First Affiliated Hospital, College of Medicine, Zhejiang University, No. 79, Qingchun St, Hangzhou 310003, Zhejiang, PR China
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Jeremy JY, Jones RA, Koupparis AJ, Hotston M, Persad R, Angelini GD, Shukla N. Reactive oxygen species and erectile dysfunction: possible role of NADPH oxidase. Int J Impot Res 2006; 19:265-80. [PMID: 17053777 DOI: 10.1038/sj.ijir.3901523] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Erectile dysfunction (ED) is a widespread condition, the incidence of which is increasing globally. ED is also indicative of underlying vasculopathy and represents a predictor of more serious cardiovascular disorders. Understanding the aetiology of ED may therefore provide invaluable pointers to the pathobiology of other cardiovascular diseases (CVDs) and syndromes. It follows, too, that therapeutic interventions that are successful in treating ED may, ipso facto, be effective in treating the early stages of conditions that include atherosclerosis, angina, plaque rupture and diabetic angiopathy. One common pathological denominator in both CVD and ED is oxidative stress, that is, the overproduction of reactive oxygen species (ROS), in particular, superoxide (O(2)(*-)) and hydrogen peroxide (H(2)O(2)). In this review, therefore, we consider the aetiology and pathobiology of O(2)(*-) in promoting ED and focus on NADPH oxidase as an inducible source of O(2)(*-) and H(2)O(2). Therapeutic strategies aimed at reducing oxidative stress to improve erectile function are also discussed.
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Affiliation(s)
- J Y Jeremy
- Department of Cardiac Surgery, Bristol Heart Institute, Bristol Royal Infirmary, The University of Bristol, Bristol, UK.
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Koupparis AJ, Jeremy J, Angelini G, Persad R, Shukla N. Penicillamine administration reverses the inhibitory effect of hyperhomocysteinaemia on endothelium-dependent relaxation in the corpus cavernosum in the rabbit. BJU Int 2006; 98:440-4. [PMID: 16879692 DOI: 10.1111/j.1464-410x.2006.06212.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To elucidate the role of copper in mediating the impact of homocysteine on vasculogenic erectile dysfunction (VED), by investigating the effect of dietary supplementation with the copper-chelator penicillamine to rabbits rendered hyperhomocysteinaemic (HHC) with a methionine-rich diet, as a raised plasma level of homocysteine might be a risk factor for VED. MATERIALS AND METHODS Homocysteine inhibits the nitric oxide (NO)-dependent relaxation of the corpus cavernosum (CC), an effect which appears to be mediated via the generation of superoxide (O2*-), and H2O2. Copper is a catalyst for the generation of H2O2 in the presence of homocysteine and in the presence of copper, H2O2 undergoes reactions resulting in the generation of O2*-, which reacts with NO to produce peroxynitrite (ONOO-), thereby reducing the bioavailability of NO and impairing NO-mediated relaxation of CC. Smooth muscle strips from CC were obtained from two groups of adult New Zealand White rabbits, one rendered HHC with a diet supplemented with methionine (group 1) and another HHC group that had additional dietary supplementation with penicillamine (group 2). Tissue O2*- levels were measured in each group. After pre-contraction with phenylephrine, relaxation responses of CC strips to carbachol were also assessed in both groups. RESULTS Methionine supplementation led to profound HHC in all rabbits. Penicillamine in group 2 reduced the total plasma Cu2+ compared to group 1. There was a markedly lower carbachol-stimulated relaxation of CC from HHC rabbits in group 1, with a mean (sem) maximum relaxation of 37 (4)% (six samples), than in group 2, at 58 (6)%. CONCLUSION These data show that elevated levels in vivo of homocysteine in the rabbit markedly impair NO-dependent relaxation of the CC. Furthermore, this effect appears to be augmented by copper. Further clinical studies on homocysteine and copper status in patients with VED are warranted.
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Tasatargil A, Sadan G, Karasu E. Homocysteine-induced changes in vascular reactivity of guinea-pig pulmonary arteries: role of the oxidative stress and poly (ADP-ribose) polymerase activation. Pulm Pharmacol Ther 2006; 20:265-72. [PMID: 16621637 DOI: 10.1016/j.pupt.2006.02.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Revised: 12/28/2005] [Accepted: 02/28/2006] [Indexed: 10/24/2022]
Abstract
This study was aimed to examine the effects of homocysteine (Hcy) on vascular responsiveness of guinea-pig isolated pulmonary arteries and to investigate possible underlying mechanisms. In order to evaluate vascular reactivity, isometric tension studies were performed in response to potassium chloride (KCl), phenylephrine (Phe), acetylcholine (ACh), and sodium nitroprusside (SNP). Incubation of pulmonary artery rings with Hcy (10(-3)M, 180min) resulted in significant inhibition of response to ACh (an endothelium-dependent vasodilator)(E(max): 55.3+/-6.7 vs. 13.1+/-2.0(*), P<0.05) while SNP (an endothelium-independent vasodilator)-induced relaxation was not changed significantly. Furthermore, Hcy enhanced KCl- and Phe-induced contraction of pulmonary artery rings (E(max): 1568+/-81 vs. 2101+/-145(*)mg for KCl and 1081+/-101 vs. 1544+/-117(*)mg for Phe, P<0.05). Pulmonary artery ring contractions induced by stepwise addition to Ca(2+) to high KCl solution with no Ca(2+) were also significantly augmented by Hcy incubation (E(max): 1750+/-121 vs. 2295+/-134(*)mg, P<0.05). To investigate mechanisms of Hcy action, additional sets of experiments involving rings incubation with Hcy alone or with addition of Tiron (an intracellular superoxide anion scavenger, 10(-2)M), PJ34 (an inhibitor of polyADP-ribose polymerase, 3x10(-6)M), and combination of two antioxidant enzymes superoxide dismutase (SOD, 100U/ml) and catalase (CAT, 120U/ml) for 180min. The findings of our study clearly show that all these co-treatments significantly prevented the development of endothelial dysfunction induced by Hcy. Furthermore, the effect of Hcy on KCl- and Phe-induced contraction was significantly inhibited by the concomitant incubation with either SOD plus CAT, Tiron or PJ34. This study demonstrates that Hcy causes a significant alteration in vascular reactivity of pulmonary arteries, and this alteration seems to be via oxidative stress in pulmonary artery endothelium with subsequent DNA damage and activation of poly(ADP-ribose) polymerase (PARP) pathway.
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Affiliation(s)
- Arda Tasatargil
- Faculty of Medicine, Department of Pharmacology, Akdeniz University, 07070, Antalya, Turkey.
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Shukla N, Koupparis A, Jones RAW, Angelini GD, Persad R, Jeremy JY. Penicillamine administration reverses the inhibitory effect of hyperhomocysteinaemia on endothelium-dependent relaxation and superoxide formation in the aorta of the rabbit. Eur J Pharmacol 2006; 531:201-8. [PMID: 16451799 DOI: 10.1016/j.ejphar.2005.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Revised: 11/29/2005] [Accepted: 12/12/2005] [Indexed: 01/26/2023]
Abstract
Although hyperhomocysteinaemia is a risk factor for cardiovascular disease, the mechanisms underlying this association have not been elucidated. It has been demonstrated, however, that copper augments the inhibitory effect of homocysteine on nitric oxide (NO)-mediated relaxation of the rat aorta through increased superoxide formation, which reacts with NO thereby reducing the bioavailability of NO. Since it follows that the administration of a copper chelator may blunt the pathogenic impact of hyperhomocysteinaemia, in vivo, the effect of penicillamine administration on NO-dependent relaxation and superoxide formation in the aortae of hyperhomocysteinaemic rabbits was studied. New Zealand White rabbits were fed a methionine-rich (20 g/kg chow) diet for 1 month+/-penicillamine administered orally (10 mg/kg/day) and aortic relaxation elicited with acetylcholine and superoxide measured. The role of NADPH oxidase was also studied using a range of inhibitors and western analysis of gp47(phox) (a catalytic subunit of NADPH oxidase). The methionine-rich diet markedly increased plasma total homocysteine levels. In hyperhomocysteinaemic rabbits there was a marked reduction of acetylcholine-stimulated relaxation and an increase in superoxide formation that were both inhibited with superoxide dismutase and apocynin, an NADPH oxidase inhibitor. Gp47(phox) expression was also increased in aortae from methionine fed rabbits. Penicillamine administration significantly reduced plasma total copper in methionine-fed rabbits compared to controls. Impaired acetylcholine-stimulated relaxation, increased superoxide formation and increased gp47(phox) expression in aortae from methionine-fed rabbits was reversed by penicillamine administration. These data indicate that hyperhomocysteinaemia augments the formation of arterial superoxide through an increase in NADPH oxidase expression/activity which in turn reduces NO bioavailability. Since these effects were reversed by penicillamine, these data consolidate the hypothesis that copper plays a role in mediating homocysteine-induced vasculopathy.
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Affiliation(s)
- Nilima Shukla
- Bristol Heart Institute, Bristol Royal Infirmary, University of Bristol, Bristol BS2 8HW, UK
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Shukla N, Maher J, Masters J, Angelini GD, Jeremy JY. Does oxidative stress change ceruloplasmin from a protective to a vasculopathic factor? Atherosclerosis 2006; 187:238-50. [PMID: 16412446 DOI: 10.1016/j.atherosclerosis.2005.11.035] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Revised: 10/30/2005] [Accepted: 11/20/2005] [Indexed: 11/28/2022]
Abstract
Although ceruloplasmin (CP), a copper containing metalloenzyme, possesses antioxidant properties (e.g. ferroxidase activity), elevated circulating CP is associated with cardiovascular disease (CVD). This ambivalence is possibly due to the capacity of CP, via its coppers, to promote vasculopathic effects that include lipid oxidation, negation of nitric oxide bioactivity and endothelial cell apoptosis. In turn, these effects that are mediated by increased formation of reactive oxygen species (ROS), such as superoxide and hydrogen peroxide. There is also evidence that risk factors for CVD (in particular, diabetes mellitus and hyperhomocysteinaemia) may augment the vasculopathic impact of CP. In turn, it appears that ROS disrupt copper binding to CP, thereby impairing its normal protective function while liberating copper which in turn may promote oxidative pathology. The objective of this review, therefore, is to consider the epidemiology and pathophysiology of CP in relation to CVD, with particular emphasis on the relationship between CP and oxidative stress.
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Affiliation(s)
- Nilima Shukla
- Bristol Heart Institute, University of Bristol, Bristol BS2 8HW, United Kingdom
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41
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Roy S, Rauk A. Alzheimer's disease and the 'ABSENT' hypothesis: mechanism for amyloid beta endothelial and neuronal toxicity. Med Hypotheses 2005; 65:123-37. [PMID: 15893129 DOI: 10.1016/j.mehy.2004.08.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Accepted: 08/13/2004] [Indexed: 12/21/2022]
Abstract
Alzheimer's disease [AD] is the most common cause of dementia among people age 65 and older. One of the biggest stumbling blocks in developing effective drug therapy for Alzheimer's disease has been the lack of a comprehensive hypothesis that explains the mechanism behind all of the histopathological changes seen in patients suffering from Alzheimer's disease. An overview of the currently popular 'amyloid' and 'vascular' hypotheses for AD demonstrates that neither hypothesis by itself can explain all the known histopathological and biochemical lesions seen in Alzheimer's disease. The paper presents a hypothesis that tries to explain the mechanism behind almost all the histopathological changes, and varying clinical manifestations seen in both diagnosed AD and Vascular Dementia [VaD]. The new hypothesis is based on the known dual toxicity of beta amyloid to both vascular and neuronal tissues, their synergy and the resultant net effect on the onset and progression of AD. The new hypothesis therefore will be known as the Amyloid Beta Synergistic Endothelial and Neuronal Toxicity [ABSENT] hypothesis. The ABSENT hypothesis will try to show the common chemical mechanism behind almost all of the pathological changes seen in AD. According to the ABSENT hypothesis, beta amyloid itself generates all the free radicals that cause both vascular dysfunction and the neuronal damage seen in AD. The chemical mechanism proposed is based on evidence from physical chemistry experiments, calculations as well as in vitro/in vivo experiments. The ABSENT hypothesis does not favor one mode of beta amyloid-induced brain damage over the other, rather it considers the net effects of the neuronal stress/damage caused by both the cerebrovascular dysfunction and direct neurotoxicity caused by beta amyloid. The hypothesis states that each patient has a different balance of predisposing factors that modulate the extent of neurotoxicity and cerebrovascular dysfunction caused by beta amyloid and thereby explains the wide range and mixed nature of damage and dysfunction seen in the studies done on patients diagnosed with AD, VaD or 'mixed dementias'. According to the hypothesis, beta amyloid peptides are necessary if not sufficient to cause AD, VaD and mixed senile dementias. The hypothesis, therefore, proposes the term Beta Amyloid Dementias [BAD] to describe the conditions currently covered by the diagnoses of 'AD', 'VaD' and 'Mixed [senile] Dementias'. Finally, the ABSENT hypothesis tries to put forth a direct chemical mechanism behind the apparent synergy and increased association between old age, pre- and coexisting vascular disease, diabetes and AD.
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Affiliation(s)
- Samir Roy
- Department of Chemistry, University of Calgary, 2500 University Drive, NW Alberta, Canada T2N 1N4.
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Miao CY, Villeneuve N, Brunel-Jacquemin C, Petit C, Guillaumin JP, Gransagne D, Briant C, Vilaine JP, Vanhoutte PM. Chronic Mild Hyperhomocysteinemia Induces Aortic Endothelial Dysfunction but Does Not Elevate Arterial Pressure in Rats. J Vasc Res 2005; 42:148-56. [PMID: 15713986 DOI: 10.1159/000083972] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Accepted: 12/29/2004] [Indexed: 11/19/2022] Open
Abstract
Mild hyperhomocysteinemia is prevalent in the general population and has been linked to endothelial dysfunction and high arterial pressure (AP) in clinical studies. The present study was designed to determine whether a rise in AP was induced by mild hyperhomocysteinemia and whether the potential rise in AP is secondary or prior to endothelial dysfunction. Experiments were performed in a rat model of mild hyperhomocysteinemia induced by oral administration of homocysteine for 1-4 months. Aortic endothelial dysfunction was observed 2 months after homocysteine treatment while endothelium-independent vasodilation was normal. In parallel, homocysteine treatment increased phenylephrine-induced contraction in aortas with endothelium, but did not modify the contraction in aortas without endothelium, suggesting a decrease of basal NO production. In conscious unrestrained rats, AP was not significantly different 1, 2, 3 and 4 months after homocysteine treatment. In correlation, endothelial function of a resistance vessel (mesenteric artery), mainly non-NO nonprostanoid factor mediated, was preserved, indicating that homocysteine treatment only affected the NO pathway. In conclusion, mild hyperhomocysteinemia alone is not sufficient to elevate arterial blood pressure, at least in the rat model. Aortic endothelial dysfunction produced by mild hyperhomocysteinemia is independent of hemodynamic factors.
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Affiliation(s)
- Chao-Yu Miao
- Cardiovascular Research Division, SERVIER Research Institute, FR-92150 Suresnes, France
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Jones RWA, Jeremy JY, Koupparis A, Persad R, Shukla N. Cavernosal dysfunction in a rabbit model of hyperhomocysteinaemia. BJU Int 2005; 95:125-30. [PMID: 15638909 DOI: 10.1111/j.1464-410x.2004.05263.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To investigate the effect of sustained hyperhomocysteinaemia (HHCy) on cavernosal smooth muscle function in a rabbit model of HHCy, developed using a methionine-enriched diet in which cavernosal responses were characterized, as elevated plasma levels of homocysteine may be a risk factor for vasculogenic erectile dysfunction. MATERIALS AND METHODS Six New Zealand White rabbits were fed a diet supplemented with methionine (20 g/kg chow) for 4 weeks, while six control animals were fed a standard diet. Cavernosal strips were mounted in an organ bath and relaxation assessed when stimulated with carbachol, sodium nitroprusside (SNP), or noncholinergic, nonadrenergic (NANC)-mediated relaxation to electrical-field stimulation (EFS). Cavernosal tissue cGMP levels were assessed using an enzyme-linked immunosorbent assay, and superoxide (O(2) (.-)) production assessed using an assay of the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c. RESULTS The methionine-rich diet led to an early but sustained HHCy; cavernosal strips from animals after 4 weeks of HHCy had a significantly impaired relaxation response to carbachol, an index of endothelium-dependent nitric oxide (NO)-mediated relaxation. This impairment was reversed by incubating with either SOD or catalase. Relaxation with either SNP, an index of endothelium-independent NO-mediated relaxation, or NANC-mediated EFS-induced relaxation, was unaffected by HHCy. There was a corresponding significant reduction in cavernosal cGMP levels (index of NO activity) in the HHCy group, with a more than five-fold increase in cavernosal tissue O(2) (.-) production. CONCLUSION Supplementing the diet of rabbits with methionine for 4 weeks caused an early and sustained HHCy and promoted a marked inhibitory effect on endothelium-dependent relaxation and NO formation in isolated corpus cavernosum, an effect mediated by reactive oxygen species.
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Affiliation(s)
- Robert W A Jones
- Bristol Heart Institute, Royal Infirmary, University of Bristol, Bristol BS2 8HW, UK
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Hucks D, Thuraisingham RC, Raftery MJ, Yaqoob MM. Homocysteine induced impairment of nitric oxide-dependent vasorelaxation is reversible by the superoxide dismutase mimetic TEMPOL. Nephrol Dial Transplant 2004; 19:1999-2005. [PMID: 15252169 DOI: 10.1093/ndt/gfh270] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Elevated plasma homocysteine concentrations in renal patients are associated with accelerated cardiovascular disease. The mechanism(s) by which homocysteine acts remains unclear however, evidence implicates a role involving endothelial dysfunction. METHODS Rat femoral arteries after acute or 4-h pre-incubation with racemic D,L-homocysteine (100 microM) were mounted on a myograph, pre-constricted with phenylephrine (10 microM) and responses to acetylcholine-dependent vasorelaxation examined. The incubations were repeated in the presence of indomethacin (10 microM), omega-nitro-L-arginine methyl ester (100 microM), L-arginine (100 microM), tetrahydrobiopterin (1 microM), catalase (1200 U/ml), ebselen, a peroxynitrite chelator (20 microM) and TEMPOL, a superoxide dismutase mimetic (1 mM). Results are shown as means+/-standard error, expressed as per cent relaxation to acetylcholine added (nmol/l). RESULTS Increasing concentrations of homocysteine had no affect when added directly to basally relaxed or pre-constricted freshly isolated vessels. However, 4-h pre-incubation with or without homocysteine significantly shifted the acetylcholine EC(50) (EC(50) was defined as the concentration of acetylcholine that caused relaxation of the phenylephrine contracted tissue by 50%), control((4 h)) = 74.7 nmol/l+/-10.5 vs 100 microM D,L-homocysteine((4 h)) = 159.9 nmol/l+/-20.6; P<0.05) without affecting maximal relaxation. Response to endothelial independent relaxation was unaffected. Indomethacin, indomethacin and omega-nitro-L-arginine methyl ester, l-arginine and tetrahydrobiopterin, catalase and ebselen had no effect on the EC(50) in homocysteine-exposed arteries. However, TEMPOL normalized vasorelaxation in homocysteine-treated arteries (75.2 nmol/l+/-14.6) but had no effect on the 4-h control group. Moreover, washing TEMPOL from the treated vessels restored endothelial dysfunction in D,L-homocysteine-treated vessels (163.9 nmol/l+/-34.1). CONCLUSIONS We conclude that homocysteine causes endothelial dysfunction by up-regulating a potential superoxide generating system resulting in reduced nitric oxide bio-availability.
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Affiliation(s)
- Davy Hucks
- Experimental Medicine, Nephrology and Critical Care, William Harvey Research Institute, Charterhouse Square, St Bartholomew's and the Royal London Hospitals, Queen Mary, University of London, London EC1M 6BQ, UK.
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Shukla N, Thompson CS, Angelini GD, Mikhailidis DP, Jeremy JY. Low micromolar concentrations of copper augment the impairment of endothelium-dependent relaxation of aortae from diabetic rabbits. Metabolism 2004; 53:1315-21. [PMID: 15375788 DOI: 10.1016/j.metabol.2004.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Both diabetes mellitus (DM) and elevated plasma copper concentrations are risk factors for cardiovascular disease (CVD). DM is associated with impaired endothelial nitric oxide (NO) and with excess superoxide (O2*-) formation. Copper is also elevated in DM and is also associated with the generation of O2*-. To explore possible interactions between DM and copper, the effect of exogenous copper (CuCl2) on endothelium-dependent relaxation and cyclic guanosine monophosphate (GMP) formation was investigated in aortae from diabetic rabbits. Rabbits were rendered diabetic by intravenous injection of alloxan. Six months after induction of DM, the aortae were excised, cut into rings, and mounted in an organ bath for isometric measurement of acetylcholine (Ach)-evoked relaxation in rings precontracted with phenylephrine (PE). In parallel studies, cyclic (c)GMP formation by aortic rings following stimulation with Ach, calcium ionophore A23187 (A23187) and sodium nitroprusside (SNP) was assessed using radioimmunoassay. The effect of copper on these parameters was then studied using the same methods. Ach-evoked relaxation and Ach- and A23187-evoked cGMP formation were significantly impaired in aortae from diabetic rabbits compared to controls, effects that were reversed with superoxide dismutase (SOD) and catalase (CAT). In contrast, there were no significant differences in SNP-stimulated relaxation or cGMP formation in aortae from diabetic rabbits compared to controls. Copper (1 to 10 micromol/L) promoted a further significant inhibition of Ach-stimulated relaxation in aortae from diabetic but not control rabbits. This reduction by copper was again reversed by SOD and CAT. We conclude that copper augments the reduction of NO bioavailability, which is already impaired in aortae from diabetic rabbits due to excess production of O2*- and H2O2. These results indicate that patients with DM may be susceptible to copper-mediated vasculopathy at much lower concentrations than those that promote vasculopathy in nondiabetic patients.
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Affiliation(s)
- N Shukla
- Bristol Heart Institute, University of Bristol, UK
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46
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Jeremy JY, Angelini GD, Shukla N. Hyperhomocysteinemia due to Helicobacter pylori? Atherosclerosis 2004; 176:201-2. [PMID: 15306196 DOI: 10.1016/j.atherosclerosis.2004.04.028] [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: 04/21/2004] [Accepted: 04/30/2004] [Indexed: 11/16/2022]
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Miller AL, Witchel HJ, Hancox JC, Jackson CL, Jeremy JY. Moderately elevated plasma homocysteine impairs functional endothelial recovery following denudation of mouse carotid arteries. Metabolism 2004; 53:760-5. [PMID: 15164325 DOI: 10.1016/j.metabol.2003.12.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Increased total plasma homocysteine is an independent risk factor for cardiovascular disease. This study was designed to determine whether it can impair endothelial function, by examining the recovery of acetylcholine-evoked relaxation following mechanical denudation of the endothelium in the arteries of cystathionine beta-synthase knockout (CbetaS(+/-)) mice. Heterozygous CbetaS(+/-) mice had total plasma homocysteine concentrations significantly higher (8.9 +/- 1.1 micromol/L, n = 12) than strain-matched wild-types (4.6 +/- 0.4 micromol/L, n = 5; P =.003). Left common carotid arteries were denuded of endothelium using a 250-microm polytetrafluoroethylene filament. After 10 days, when the endothelium had completely regrown, relaxation to acetylcholine was measured in precontracted segments of artery. Uninjured right carotid arteries from the same animals served as internal controls. Relaxation to acetylcholine was significantly attenuated in the injured arteries of the CbetaS(+/-) mice, compared to wild-types (P =.017); furthermore, there was a significant negative correlation between sensitivity to acetylcholine and total plasma homocysteine concentration measured in the same animal (r = -0.69, P <.003). These data suggest that even modest homocysteinemia has a deleterious effect on the function of healed endothelium in mouse arteries. This may account for its adverse influence on chronic cardiovascular disease.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Carotid Artery Injuries/metabolism
- Carotid Artery Injuries/pathology
- Carotid Artery, Common/drug effects
- Carotid Artery, Common/metabolism
- Carotid Artery, Common/pathology
- Carotid Artery, Common/ultrastructure
- Cystathionine beta-Synthase/genetics
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiology
- Homocysteine/blood
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle Contraction/drug effects
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/drug effects
- Recovery of Function
- Vasodilation/drug effects
- Vasodilator Agents/pharmacology
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Shukla N, Angelini GD, Jeremy JY. To: Looker HC, Fagot-Campagna A, Gunter EW et al. (2003) Homocysteine as a risk factor for nephropathy and retinopathy in Type 2 diabetes. Diabetologia 46:766-772. Diabetologia 2004; 47:140-1. [PMID: 14628110 DOI: 10.1007/s00125-003-1259-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2003] [Revised: 08/13/2003] [Indexed: 11/30/2022]
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Fu YF, Xiong Y, Fu SH. Captopril Restores Endothelium-Dependent Relaxation of Rat Aortic Rings After Exposure to Homocysteine. J Cardiovasc Pharmacol 2003; 42:566-72. [PMID: 14508244 DOI: 10.1097/00005344-200310000-00016] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This study was designed to investigate the effects of captopril, an angiotensin-converting enzyme inhibitor, on inhibition of endothelium-dependent relaxation induced by homocysteine in isolated rat aorta. Isometric tension recordings were used to assess inhibitory effects of homocysteine and protective effects of captopril on endothelium-dependent relaxation of aortic rings. Exposure of aortic rings to homocysteine (0.3 approximately 3 mmol/L) for 30 min induced a significant concentration-dependent inhibition of endothelium-dependent relaxation response to acetylcholine (ACh), but did not affect endothelium-independent relaxation response to sodium nitroprusside. Pre-incubation of aortic rings with captopril (3 approximately 30 micromol/L) for 15 min and co-incubation of aortic rings with homocysteine (1 mmol/L) for another 30 min attenuated the inhibition of homocysteine in a dose-dependent manner. Moreover, superoxide dismutase (SOD, 200 U/mL), a scavenger of superoxide anions, reduced homocysteine-induced inhibition. L-Arginine (3 mmol/L), a precursor of nitric oxide (NO), also attenuated the impairment of vasorelaxation induced by homocysteine. However, in the combined presence of SOD and L-arginine, the inhibitory effect of homocysteine was reversed, which was very similar to the effect of 30 micromol/L captopril. These results suggest that captopril can prevent the inhibition of endothelium-dependent relaxation induced by homocysteine in isolated rat aorta, which may be related to scavenging oxygen free radicals and enhancing NO production.
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Affiliation(s)
- Yun-feng Fu
- Department of Pharmacology, Xiang-ya Medical College, Central South University, Hunan, PR China
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50
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Konukoğlu D, Serin O, Ercan M, Turhan MS. Plasma homocysteine levels in obese and non-obese subjects with or without hypertension; its relationship with oxidative stress and copper. Clin Biochem 2003; 36:405-8. [PMID: 12849875 DOI: 10.1016/s0009-9120(03)00059-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVES The relationship between plasma total Homocysteine (tHcy) and oxidative stress and plasma levels of lipids, insulin and copper levels were investigated in obese and nonobese hypertensives. DESIGN AND METHODS Plasma tHcy levels were determined by an enzyme immunoassay method. Plasma lipid peroxidation levels were measured as thiobarbituric acid reactive substances (TBARS) by spectrophotometric methods. Plasma levels of copper and insulin were measured by atomic absorption spectrophotometer and electrochemiluminescence method, respectively. RESULTS Plasma tHcy, copper and insulin levels did not differ in nonobese hypertensives compared to nonobese normotensives. Plasma TBARS levels were significantly increased in nonobese hypertensives when compared to nonobese normotensives (p < 0.001). Plasma tHcy, TBARS, copper and fasting insulin levels were significantly higher in obese normotensives and hypertensives than in nonobese normotensives and hypertensives, respectively (for each comparison; p < 0.001). There was a significant difference in plasma tHcy, TBARS and copper levels between obese subjects with or without hypertension (for each comparison p < 0.01). The univariate analyses demonstrated a significant positive correlation between tHcy and TBARS (coefficient +/- SE, 0.411 +/- 0.115, p < 0.01) and copper (coefficient +/- SE, 0.425 +/- 0.135, p < 0.01) in obese subjects. In a multivariate regression analysis in obese subjects tHcy was positively correlated with TBARS (coefficient +/- SE, 0.480 +/- 0.155, p < 0.01) and copper (coefficient +/- SE, 0.486 +/- 0.140, p < 0.01). CONCLUSIONS We hypothesize that in the presence of other traditional risk factors, Hcy may have a permissive role in the endothelium damage even within the normal range and this role may be related to free radical generating systems. Therefore, modest elevation of plasma Hcy may causally be involved in the pathogenesis of atherosclerosis and/or cardiovascular disease.
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Affiliation(s)
- Dildar Konukoğlu
- Istanbul University, Biochemistry Department of Cerrahpasa Medical Faculty, Istanbul, Turkey.
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