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Rupa SA, Patwary MAM, Matin MM, Ghann WE, Uddin J, Kazi M. Interaction of mercury species with proteins: towards possible mechanism of mercurial toxicology. Toxicol Res (Camb) 2023; 12:355-368. [PMID: 37397928 PMCID: PMC10311172 DOI: 10.1093/toxres/tfad039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 05/02/2023] [Accepted: 05/15/2023] [Indexed: 07/04/2023] Open
Abstract
The nature of the binding of mercurials (organic and inorganic) and their subsequent transformations in biological systems is a matter of great debate as several different hypotheses have been proposed and none of them has been conclusively proven to explain the characteristics of Hg binding with the proteins. Thus, the chemical nature of Hg-protein binding through the possible transportation mechanism in living tissues is critically reviewed herein. Emphasis is given to the process of transportation, and binding of Hg species with selenol-containing biomolecules that are appealing for toxicological studies as well as the advancement of environmental and biological research.
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Affiliation(s)
| | | | | | - William Emmanuel Ghann
- Center for Nanotechnology, Department of Natural Sciences, Coppin State University, Baltimore, MD 21216, USA
| | - Jamal Uddin
- Center for Nanotechnology, Department of Natural Sciences, Coppin State University, Baltimore, MD 21216, USA
| | - Mohsin Kazi
- Department of Pharmaceutics, College of Pharmacy, King Saud University, P.O. BOX-2457, Riyadh 11451, Saudi Arabia
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2
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Tang J, Zhu Q, Xu Y, Zhou Y, Zhu L, Jin L, Wang W, Gao L, Chen G, Zhao H. Total arsenic, dimethylarsinic acid, lead, cadmium, total mercury, methylmercury and hypertension among Asian populations in the United States: NHANES 2011-2018. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 241:113776. [PMID: 35738098 DOI: 10.1016/j.ecoenv.2022.113776] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/08/2022] [Accepted: 06/13/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND Non-Hispanic Asians (NHA) in USA have been reported with higher arsenic (As), lead (Pb), cadmium (Cd), mercury (Hg) and their specific species levels, comparing with non-NHA. This study aimed to investigate the associations of these metal/metalloid levels with blood pressure levels and prevalence of hypertension among general NHA using the 2011-2018 National Health and Nutrition and Examination Survey (NHANES) data. METHODS The study included participants aged 20 years and older with determinations of As, Dimethylarsinic acid (DMA), Pb, Cd, Hg and methyl-Hg (MeHg) in blood (n = 10, 177) and urine (n = 5, 175). These metals/metalloid levels were measured by inductively coupled plasma mass spectrometry. Systolic (SBP) and diastolic blood pressure (DBP) levels were examined through a standardized protocol. Censored normal regression model and logistic regression model were employed to explore the associations of As, DMA, Pb, Cd, Hg and MeHg levels with blood pressure levels and prevalence of hypertension respectively, and potential confounders were adjusted in these regression models. Quantile-based g-computation approach was used to analysis joint effect of metals mixture on blood pressure level and hypertension. RESULTS For NHA, urinary As and Hg levels were associated with increased DBP level; Higher blood Hg and MeHg levels were related to increased blood pressure levels and hypertension; However, negative association was observed between urinary Cd and SBP level; Blood metals mixture (including blood Pb, Cd and Hg) was associated with increased DBP level, but not for hypertension. For non-NHA, urinary As and DMA levels were associated with increased SBP level, but not DBP level and prevalence of hypertension; Urinary Pb level was associated with decreased DBP level; Nevertheless, positive associations were observed between blood Pb levels and SBP and prevalence of hypertension; Blood Hg level was associated with decreased DBP level and prevalence of hypertension; Furthermore, blood MeHg level was associated with decreased DBP level; Positive association was observed between blood metals mixture and increased SBP level among non-NHA. CONCLUSIONS Highly exposed to Hg level among NHA was associated with increased blood pressure levels and prevalence of hypertension. Urinary As level was associated with increased DBP level among NHA. Furthermore, blood metals mixture was related to increased DBP level among NHA. Further prospective studies with larger sample size should be performed to warrant the results.
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Affiliation(s)
- Jun Tang
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, China
| | - Qinheng Zhu
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yang Xu
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yexinyi Zhou
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Longtao Zhu
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lanfei Jin
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Weiye Wang
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China; Department of public health and preventive medicine, school of medicine, Jinggangshan university, Ji'an, China
| | - Lan Gao
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Guangdi Chen
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China.
| | - Hao Zhao
- Department of Public Health, and Department of Reproductive Endocrinology of Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China; Department of Social Medicine and Public Health, School of Basic Medicine, Jiujiang University, Jiujiang, China.
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3
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Sun Y, Liu B, Rong S, Zhang J, Du Y, Xu G, Snetselaar LG, Wallace RB, Lehmler HJ, Bao W. Association of Seafood Consumption and Mercury Exposure With Cardiovascular and All-Cause Mortality Among US Adults. JAMA Netw Open 2021; 4:e2136367. [PMID: 34842923 PMCID: PMC8630568 DOI: 10.1001/jamanetworkopen.2021.36367] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
IMPORTANCE Although seafood is known to contain heart-healthy omega-3 fatty acids, many people choose to limit their seafood consumption because of fear of mercury exposure from seafood. It is imperative to clarify the potential health effects of current mercury exposure in contemporary populations. OBJECTIVE To examine the association of seafood consumption and mercury exposure with all-cause and cardiovascular disease (CVD)-related mortality in the US general population. DESIGN, SETTING, AND PARTICIPANTS This prospective cohort study included adults 20 years or older who participated in the 2003 to 2012 cycles of the National Health and Nutrition Examination Survey; data were linked to mortality records through December 31, 2015. Data analysis was performed from January to March 10, 2021. EXPOSURES Seafood consumption was assessed through two 24-hour dietary recalls, and mercury exposure was assessed by blood mercury levels. MAIN OUTCOMES AND MEASURES All-cause and CVD-related mortality. Multivariable Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% CIs of mortality associated with usual seafood consumption and blood mercury concentration quartiles. RESULTS This study included 17 294 participants (mean [SD] age, 45.9 [17.1] years; 9217 [53.3%] female) with a mean (SD) blood mercury concentration of 1.62 (2.46) μg/L. During 131 276 person-years of follow-up, 1076 deaths occurred, including 181 deaths from CVD. The multivariable-adjusted HR for an increase in seafood consumption of 1 oz equivalent per day and all-cause mortality was 0.84 (95% CI, 0.66-1.07) and for CVD-related mortality was 0.89 (95% CI, 0.54-1.47). Blood mercury level was not associated with all-cause or CVD-related mortality. Comparing the highest with the lowest quartile of blood mercury concentration, the multivariable-adjusted HRs were 0.82 (95% CI, 0.66-1.05) for all-cause mortality and 0.90 (95% CI, 0.53-1.52) for CVD-related mortality. CONCLUSIONS AND RELEVANCE In this cohort study of US adults, seafood consumption and mercury exposure with the current seafood consumption level were not significantly associated with the risk of all-cause or CVD-related mortality. These findings may inform future public health guidelines regarding mercury exposure, seafood consumption, and cardiovascular health promotion.
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Affiliation(s)
- Yangbo Sun
- Department of Preventive Medicine, College of Medicine, The University of Tennessee Health Science Center, Memphis
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
| | - Buyun Liu
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
| | - Shuang Rong
- Department of Nutrition and Food Hygiene, School of Public Health, Medical College, Wuhan University of Science and Technology, Wuhan, China
| | - Jing Zhang
- Department of Environmental Health, School of Public Health, Jining Medical University, Jining, China
| | - Yang Du
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
| | - Guifeng Xu
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
| | - Linda G. Snetselaar
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
| | - Robert B. Wallace
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
| | - Hans-Joachim Lehmler
- Department of Occupational and Environmental Health, College of Public Health, University of Iowa, Iowa City
| | - Wei Bao
- Department of Epidemiology, College of Public Health, University of Iowa, Iowa City
- Obesity Research and Education Initiative, University of Iowa, Iowa City
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City
- Now with Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
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Miguel M, Vassallo DV, Wiggers GA. Bioactive Peptides and Hydrolysates from Egg Proteins as a New Tool for Protection Against Cardiovascular Problems. Curr Pharm Des 2021; 26:3676-3683. [PMID: 32216734 DOI: 10.2174/1381612826666200327181458] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/12/2020] [Indexed: 01/21/2023]
Abstract
The aim of the present work is to review the potential beneficial effects of dietary supplementation with bioactive egg protein hydrolysates or peptides on cardiometabolic changes associated with oxidative stress. The development of nutritionally improved food products designed to address specific health concerns is of particular interest because many bioactive food compounds can be potentially useful in various physiological functions such as for reducing oxidative stress. The results presented suggest that egg hydrolysates or derived peptides could be included in the diet to prevent and/or reduce some cardiometabolic complications associated with oxidative stress-related diseases.
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Affiliation(s)
- Marta Miguel
- Bioactivity and Food Analysis Laboratory, Instituto de Investigación em Ciencias de la Alimentación, Nicolás Cabrera, 9, Campus Universitario de Cantoblanco, Madrid, Spain
| | - Dalton V Vassallo
- Department of Physiological Sciences, Universidade Federal do Espirito Santo and School of Medicine of Santa Casa de Misericordia (EMESCAM), Av. Marechal Campos 1468, Zip Code: 29040-090, Vitoria, Espirito Santo, Brazil
| | - Giulia A Wiggers
- Cardiovascular Physiology Research Group, Federal University of Pampa, BR 472 - Km 592 - PO box 118. Zip Code: 97500-970, Uruguaiana, Rio Grande do Sul, Brazil
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5
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Yao B, Lu X, Xu L, Wang Y, Qu H, Zhou H. Relationship between low-level lead, cadmium and mercury exposures and blood pressure in children and adolescents aged 8-17 years: An exposure-response analysis of NHANES 2007-2016. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 726:138446. [PMID: 32320874 DOI: 10.1016/j.scitotenv.2020.138446] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 04/01/2020] [Accepted: 04/02/2020] [Indexed: 06/11/2023]
Abstract
This study investigated whether low-level blood and urinary lead, cadmium and mercury exposures were associated with blood pressure (BP) in children and adolescents. Data from National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016 for children and adolescents aged 8-17 years (n = 7076) were analyzed. Outcome variables were systolic BP, diastolic BP and high BP status. High BP was defined as: self-reported antihypertensive medication usage or a diagnosis of hypertension; classified as having elevated BP/hypertension according to 2017 AAP guidelines. Multivariable linear and logistic regressions models were performed and stratified by race/ethnicity and gender. Blood lead was negatively associated with diastolic BP among blacks, and positively associated with diastolic BP among whites. For a two-fold increase of blood lead concentration, the change in diastolic BP was -1.59 mm Hg (95% CI: -3.04 to -0.16 mm Hg) among blacks and 1.38 mm Hg (95% CI: 0.40 to 2.36 mm Hg) among whites. No significant associations between either systolic BP or diastolic BP with urinary lead were observed. The inverse associations between blood lead and high BP were found in females, Mexican Americans and other Hispanics. No associations between blood cadmium and BP were observed, except in other Hispanics. Urinary cadmium levels were inversely correlated with systolic BP, diastolic BP and high BP in all participants and in men. When compared to the lowest quartile of urinary cadmium levels, participants with a urinary cadmium level ≥ 0.12 μg/L had 0.48 (95% CI: 0.29-0.78) times and 0.53 (95% CI: 0.30-0.94) times reduced odds of having high BP in all participants and in men, respectively. No associations between either blood mercury or urinary mercury with systolic BP were observed. Significant inverse associations were found between blood total mercury and methyl mercury with diastolic BP in all participants and in men. Future prospective studies are warranted to confirm these findings.
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Affiliation(s)
- Baodong Yao
- Department of Cardiology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Institute of Cardiovascular Disease Research, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, China
| | - Xiaojing Lu
- Department of Performance Management, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Lai Xu
- Department of Performance Management, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yue Wang
- Department of Cardiology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Institute of Cardiovascular Disease Research, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, China
| | - Huiyan Qu
- Department of Cardiology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Institute of Cardiovascular Disease Research, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, China.
| | - Hua Zhou
- Department of Cardiology, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Institute of Cardiovascular Disease Research, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, China.
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6
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Gökçe G, Arun MZ, Ertuna E. Ergothioneine prevents endothelial dysfunction induced by mercury chloride. Exp Ther Med 2018; 15:4697-4702. [PMID: 29805489 PMCID: PMC5958736 DOI: 10.3892/etm.2018.6079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/22/2018] [Indexed: 01/23/2023] Open
Abstract
Exposure to mercury has detrimental effects on the cardiovascular system, particularly the vascular endothelium. The present study aimed to investigate the effects of ergothioneine (EGT) on endothelial dysfunction induced by low-dose mercury chloride (HgCl2). Agonist-induced contractions and relaxations were evaluated in isolated aortic rings from 3-month-old male Wistar rats treated by intra-muscular injection to caudal hind leg muscle with HgCl2 (first dose, 4.6 µg/kg; subsequent doses, 0.07 µg/kg/day for 15 days) and optionally with EGT (2 µg/kg for 30 days). Reactive oxygen species (ROS) in aortic rings were measured by means of lucigenin- and luminol-enhanced chemiluminescence. The protein level of endothelial nitric oxide synthase was evaluated by ELISA. Blood glutathione (GSH) and catalase levels, lipid peroxidation and total nitrite were measured spectrophotometrically. The results indicated that low-dose HgCl2 administration impaired acetylcholine (ACh)-induced relaxation and potentiated phenylephrine- and serotonin-induced contractions in rat aortas. In addition, HgCl2 significantly increased the levels of ROS in the aortic tissue. EGT prevented the loss of ACh-induced relaxations and the increase in contractile responses. These effects were accompanied by a significant decrease in ROS levels. EGT also improved the ratio of reduced GSH to oxidized GSH and catalase levels with a concomitant decrease in lipid peroxidation. In conclusion, to the best of our knowledge, the present study was the first to report that EGT prevents endothelial dysfunction induced by low-dose HgCl2 administration. EGT may serve as a therapeutic tool to reduce mercury-associated cardiovascular complications via improving the antioxidant status.
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Affiliation(s)
- Göksel Gökçe
- Department of Clinical Pharmacy, Faculty of Pharmacy, Ege University, Izmir 35040, Turkey
| | - Mehmet Zuhuri Arun
- Department of Clinical Pharmacy, Faculty of Pharmacy, Ege University, Izmir 35040, Turkey
| | - Elif Ertuna
- Department of Clinical Pharmacy, Faculty of Pharmacy, Ege University, Izmir 35040, Turkey
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7
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Monteiro DA, Taylor EW, Rantin FT, Kalinin AL. Impact of waterborne and trophic mercury exposures on cardiac function of two ecologically distinct Neotropical freshwater fish Brycon amazonicus and Hoplias malabaricus. Comp Biochem Physiol C Toxicol Pharmacol 2017; 201:26-34. [PMID: 28939505 DOI: 10.1016/j.cbpc.2017.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/14/2017] [Accepted: 09/16/2017] [Indexed: 01/09/2023]
Abstract
Metal pollutants have been considered one of the main factors underlying the depletion of biodiversity in natural populations unbalancing aquatic environments. The aim of this study was to evaluate the effects of exposure to inorganic Hg on myocardial contractility and the electrocardiogram (ECG) of two ecologically distinct Neotropical fish species, namely: matrinxã (Brycon amazonicus) and trahira (Hoplias malabaricus). Matrinxãs were exposed to a sublethal concentration of 0.1mgL-1 of Hg in water for 96h. Trahiras were exposed to dietary Hg doses (0.45mg of Hg, each 4days, for 30days) using juvenile B. amazonicus as the prey vehicle. Hg exposures decreased myocardial isometric twitch force development, harmed contraction/relaxation dynamics and cardiac pumping capacity (CPC), and reduced the relative contribution of the calcium stored in the sarcoplasmic reticulum (SR) to excitation contraction (EC) coupling in both fish species. Analysis of the ECG revealed that Hg impaired electrical conduction across the heart, inducing first degree atrioventricular block and lengthening the plateau phase of action potential duration. In trahira trophic doses of Hg induced a marked bradycardia, increasing the duration of the ventricular action potential and delaying atrial and ventricular depolarization. These findings indicate that both acute and long-term Hg exposure, by different routes is cardiotoxic to matrinxã and trahira. Hg potently impaired intracellular calcium kinetics in the cardiomyocytes, myocardium contractility, and electrical conduction across the heart, all of which can be implicated in decreased cardiac output and putative heart failure.
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Affiliation(s)
- Diana A Monteiro
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13565-905, São Paulo, Brazil.
| | - Edwin W Taylor
- School of Biological Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Francisco T Rantin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13565-905, São Paulo, Brazil
| | - Ana L Kalinin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos 13565-905, São Paulo, Brazil
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Rizzetti DA, Torres JGD, Escobar AG, da Silva TM, Moraes PZ, Hernanz R, Peçanha FM, Castro MM, Vassallo DV, Salaices M, Alonso MJ, Wiggers GA. The cessation of the long-term exposure to low doses of mercury ameliorates the increase in systolic blood pressure and vascular damage in rats. ENVIRONMENTAL RESEARCH 2017; 155:182-192. [PMID: 28222365 DOI: 10.1016/j.envres.2017.02.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 06/06/2023]
Abstract
This study aimed to verify whether a prolonged exposure to low-level mercury promotes haemodynamic disorders and studied the reversibility of this vascular damage. Rats were divided into seven groups: three control groups received saline solution (im) for 30, 60 or 90 days; two groups received HgCl2 (im, first dose, 4.6μg/kg, subsequent doses 0.07μg/kg/day) for 30 or 60 days; two groups received HgCl2 for 30 or 60 days (im, same doses) followed by a 30-day washout period. Systolic blood pressure (SBP) was measured, along with analysis of vascular response to acetylcholine (ACh) and phenylephrine (Phe) in the absence and presence of endothelium, a nitric oxide (NO) synthase inhibitor, an NADPH oxidase inhibitor, superoxide dismutase, a non-selective cyclooxygenase (COX) inhibitor and an AT1 receptor blocker. Reactive oxygen species (ROS) levels and antioxidant power were measured in plasma. HgCl2 exposure for 30 and 60 days: a) reduced the endothelium-dependent relaxation; b) increased the Phe-induced contraction and the contribution of ROS, COX-derived vasoconstrictor prostanoids and angiotensin II acting on AT1 receptors to this response while the NO participation was reduced; c) increased the oxidative stress in plasma; d) increased the SBP only after 60 days of exposure. After the cessation of HgCl2 exposure, SBP, endothelium-dependent relaxation, Phe-induced contraction and the oxidative stress were normalised, despite the persistence of the increased COX-derived prostanoids. These results demonstrated that long-term HgCl2 exposure increases SBP as a consequence of vascular dysfunction; however, after HgCl2 removal from the environment the vascular function ameliorates.
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Affiliation(s)
| | | | - Alyne Goulart Escobar
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - Taiz Martins da Silva
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil; Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón, Spain; Bioactivity and Food Analysis Laboratory, Instituto de Investigación en Ciencias de la Alimentación, Madrid, Spain; Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil; Department of Pharmacology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Paola Zambelli Moraes
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - Raquel Hernanz
- Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón, Spain
| | - Franck Maciel Peçanha
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - Marta Miguel Castro
- Bioactivity and Food Analysis Laboratory, Instituto de Investigación en Ciencias de la Alimentación, Madrid, Spain
| | - Dalton Valentim Vassallo
- Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil
| | - Mercedes Salaices
- Department of Pharmacology, Universidad Autónoma de Madrid, Madrid, Spain
| | - Maria Jesús Alonso
- Department of Basic Health Sciences, Universidad Rey Juan Carlos, Alcorcón, Spain
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9
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An Investigation of Organic and Inorganic Mercury Exposure and Blood Pressure in a Small-Scale Gold Mining Community in Ghana. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:10020-38. [PMID: 26308023 PMCID: PMC4555326 DOI: 10.3390/ijerph120810020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 07/28/2015] [Accepted: 08/17/2015] [Indexed: 02/07/2023]
Abstract
There is increasing concern about the cardiovascular effects of mercury (Hg) exposure, and that organic methylmercury and inorganic Hg2+ may affect the cardiovascular system and blood pressure differentially. In small-scale gold mining communities where inorganic, elemental Hg exposures are high, little is known about the effects of Hg on blood pressure. In 2011, we assessed the relationship between Hg exposure and blood pressure (BP) in a cross-sectional study of adults from a small-scale gold mining community, Kejetia, and subsistence farming community, Gorogo, in Ghana’s Upper East Region. Participants’ resting heart rate and BP were measured, and hair and urine samples were provided to serve as biomarkers of organic and inorganic Hg exposure, respectively. Participants included 70 miners and 26 non-miners from Kejetia and 75 non-miners from Gorogo. Total specific gravity-adjusted urinary and hair Hg was higher among Kejetia miners than Kejetia non-miners and Gorogo participants (median urinary Hg: 5.17, 1.18, and 0.154 µg/L, respectively; hair Hg: 0.945, 0.419, and 0.181 µg/g, respectively). Hypertension was prevalent in 17.7% of Kejetia and 21.3% of Gorogo participants. Urinary and hair Hg were not significantly associated with systolic or diastolic BP for Kejetia or Gorogo participants while adjusting for sex, age, and smoking status. Although our results follow trends seen in other studies, the associations were not of statistical significance. Given the unique study population and high exposures to inorganic Hg, the work contained here will help increase our understanding of the cardiovascular effects of Hg.
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10
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Fernandes AA, Faria TDO, Ribeiro Júnior RF, Costa GP, Marchezini B, Silveira EA, Angeli JK, Stefanon I, Vassallo DV, Lizardo JH. A single resistance exercise session improves myocardial contractility in spontaneously hypertensive rats. ACTA ACUST UNITED AC 2015; 48:813-21. [PMID: 26176315 PMCID: PMC4568809 DOI: 10.1590/1414-431x20154355] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 03/20/2015] [Indexed: 01/03/2023]
Abstract
Resistance training evokes myocardial adaptation; however, the effects of a single
resistance exercise session on cardiac performance are poorly understood or
investigated. This study aimed to investigate the effects of a single resistance
exercise session on the myocardial contractility of spontaneously hypertensive rats
(SHRs). Male 3-month-old SHRs were divided into two groups: control (Ct) and exercise
(Ex). Control animals were submitted to sham exercise. Blood pressure was measured in
conscious rats before the exercise session to confirm the presence of arterial
hypertension. Ten minutes after the exercise session, the animals were anesthetized
and killed, and the hearts were removed. Cardiac contractility was evaluated in the
whole heart by the Langendorff technique and by isometric contractions of isolated
left ventricular papillary muscles. SERCA2a, phospholamban (PLB), and phosphorylated
PLB expression were investigated by Western blot. Exercise increased force
development of isolated papillary muscles (Ex=1.0±0.1 g/mg vs
Ct=0.63±0.2 g/mg, P<0.05). Post-rest contraction was greater in the exercised
animals (Ex=4.1±0.4% vs Ct=1.7±0.2%, P<0.05). Papillary muscles
of exercised animals developed greater force under increasing isoproterenol
concentrations (P<0.05). In the isolated heart, exercise increased left
ventricular isovolumetric systolic pressure (LVISP; Δ +39 mmHg; P<0.05) from
baseline conditions. Hearts from the exercised rats presented a greater response to
increasing diastolic pressure. Positive inotropic intervention to calcium and
isoproterenol resulted in greater LVISP in exercised animals (P<0.05). The results
demonstrated that a single resistance exercise session improved myocardial
contractility in SHRs.
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Affiliation(s)
- A A Fernandes
- Departamento de Morfologia, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - T de O Faria
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - R F Ribeiro Júnior
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - G P Costa
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - B Marchezini
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - E A Silveira
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - J K Angeli
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - I Stefanon
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, BR
| | - D V Vassallo
- Departamento de Ciências Fisiológicas, Escola Superior de Ciências da Santa Casa de Misericórdia de Vitória, Vitória, ES, BR
| | - J H Lizardo
- Departamento de Morfologia, Universidade Federal do Espírito Santo, Vitória, ES, BR
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11
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Park SK, Lee S, Basu N, Franzblau A. Associations of blood and urinary mercury with hypertension in U.S. adults: the NHANES 2003-2006. ENVIRONMENTAL RESEARCH 2013; 123:25-32. [PMID: 23472608 PMCID: PMC3644317 DOI: 10.1016/j.envres.2013.02.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 01/22/2013] [Accepted: 02/05/2013] [Indexed: 05/03/2023]
Abstract
BACKGROUND Few studies have examined the association between hypertension and mercury exposure in the general population. We examined cross-sectional associations between blood (mainly methylmercury) or urinary mercury (mainly inorganic mercury) and hypertension in representative U.S. adults and effect modifications by dietary omega-3 fatty acids and serum selenium. METHODS We examined 6607 adults aged 20 years or older, using the National Health and Nutrition Examination Survey (NHANES) from 2003/2004 to 2005/2006 (2201 adults were available for urinary mercury from NHANES 2003-2006; 2117 available for serum selenium from NHANES 2003-2004 aged 40 years or older). The average of omega-3 fatty acids from two 24-h recalls was calculated. RESULTS The weighted prevalence of hypertension was 32.2%. The geometric means (95% confidence intervals) of blood total and urinary mercury were 1.03 (0.95, 1.11)μg/L and 0.51 (0.47, 0.54)μg/L, respectively. The adjusted odds ratios for a doubling increase in blood mercury and urinary mercury were 0.94 (0.87 to 1.01) and 0.87 (0.78 to 0.99), respectively, after adjusting for potential confounders. The associations remained similar, even after adjusting for either omega-3 fatty acids or selenium or both. No significant effect modification by either omega-3 fatty acids or selenium was observed. CONCLUSIONS In this cross-sectional study of the U.S. general population, we found no association of hypertension with blood mercury but a suggestive inverse association with urinary mercury. Future prospective studies are warranted to confirm these findings.
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Affiliation(s)
- Sung Kyun Park
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA.
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12
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Marques FS, Silva JS, Couto RD, Junior EPDSB, Ribeiro-dos-Santos R, Santos WLCD, Soares MBP. Transplantation of Bone Marrow Mononuclear Cells Reduces Mortality and Improves Renal Function on Mercury-Induced Kidney Injury in Mice. Ren Fail 2013; 35:776-81. [DOI: 10.3109/0886022x.2013.780660] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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13
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Goodrich JM, Wang Y, Gillespie B, Werner R, Franzblau A, Basu N. Methylmercury and elemental mercury differentially associate with blood pressure among dental professionals. Int J Hyg Environ Health 2013; 216:195-201. [PMID: 22494934 PMCID: PMC3727420 DOI: 10.1016/j.ijheh.2012.03.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 02/25/2012] [Accepted: 03/08/2012] [Indexed: 02/07/2023]
Abstract
Methylmercury-associated effects on the cardiovascular system have been documented though discrepancies exist, and most studied populations experience elevated methylmercury exposures. No paper has investigated the impact of low-level elemental (inorganic) mercury exposure on cardiovascular risk in humans. The purpose of this study was to increase understanding of the association between mercury exposure (methylmercury and elemental mercury) and blood pressure measures in a cohort of dental professionals that experience background exposures to both mercury forms. Dental professionals were recruited during the 2010 Michigan Dental Association Annual Convention. Mercury levels in hair and urine samples were analyzed as biomarkers of methylmercury and elemental mercury exposure, respectively. Blood pressure (systolic, diastolic) was measured using an automated device. Distribution of mercury in hair (mean, range: 0.45, 0.02-5.18 μg/g) and urine (0.94, 0.03-5.54 μg/L) correspond well with the US National Health and Nutrition Examination Survey. Linear regression models revealed significant associations between diastolic blood pressure (adjusted for blood pressure medication use) and hair mercury (n=262, p=0.02). Urine mercury results opposed hair mercury in many ways. Notably, elemental mercury exposure was associated with a significant systolic blood pressure decrease (n=262, p=0.04) that was driven by the male population. Associations between blood pressure and two forms of mercury were found at exposure levels relevant to the general population, and associations varied according to type of mercury exposure and gender.
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Affiliation(s)
- Jaclyn M. Goodrich
- Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA
| | - Yi Wang
- Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA
| | - Brenda Gillespie
- Department of Biostatistics, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA
| | - Robert Werner
- Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA
- Department of Physical Medicine and Rehabilitation, University of Michigan, 325 E. Eisenhower Parkway Suite 100, Ann Arbor, MI 48108, USA
| | - Alfred Franzblau
- Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA
| | - Niladri Basu
- Department of Environmental Health Sciences, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA
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14
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Rizzetti DA, Torres JGD, Escobar AG, Peçanha FM, Santos FW, Puntel RL, Alonso MJ, Briones AM, Salaices M, Vassallo DV, Wiggers GA. Apocynin prevents vascular effects caused by chronic exposure to low concentrations of mercury. PLoS One 2013; 8:e55806. [PMID: 23390552 PMCID: PMC3563583 DOI: 10.1371/journal.pone.0055806] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 01/02/2013] [Indexed: 11/19/2022] Open
Abstract
Mercury increases the risk of cardiovascular disease and oxidative stress and alters vascular reactivity. This metal elicits endothelial dysfunction causing decreased NO bioavailability via increased oxidative stress and contractile prostanoid production. NADPH oxidase is the major source of reactive oxygen species (ROS) in the vasculature. Our aim was to investigate whether treatment with apocynin, an NADPH oxidase inhibitor, prevents the vascular effects caused by chronic intoxication with low concentrations of mercury. Three-month-old male Wistar rats were treated for 30 days with a) intramuscular injections (i.m.) of saline; b) HgCl2 (i.m. 1st dose: 4.6 µg/kg, subsequent doses: 0.07 µg/kg/day); c) Apocynin (1.5 mM in drinking water plus saline i.m.); and d) Apocynin plus HgCl2. The mercury treatment resulted in 1) an increased aortic vasoconstrictor response to phenylephrine and reduced endothelium-dependent responses to acetylcholine; 2) the increased involvement of ROS and vasoconstrictor prostanoids in response to phenylephrine, whereas the endothelial NO modulation of such responses was reduced; and 3) the reduced activity of aortic superoxide dismutase (SOD) and glutathione peroxidase (GPx) and increased plasma malondialdehyde (MDA) levels. Treatment with apocynin partially prevented the increased phenylephrine responses and reduced the endothelial dysfunction elicited by mercury treatment. In addition, apocynin treatment increased the NO modulation of vasoconstrictor responses and aortic SOD activity and reduced plasma MDA levels without affecting the increased participation of vasoconstrictor prostanoids observed in aortic segments from mercury-treated rats. Conclusions: Mercury increases the vasoconstrictor response to phenylephrine by reducing NO bioavailability and increasing the involvement of ROS and constrictor prostanoids. Apocynin protects the vessel from the deleterious effects caused by NADPH oxidase, but not from those caused by prostanoids, thus demonstrating a two-way action.
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Affiliation(s)
- Danize A. Rizzetti
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | | | - Alyne G. Escobar
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - Franck M. Peçanha
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - Francielli W. Santos
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - Robson L. Puntel
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
| | - María J. Alonso
- Department of Biochemistry, Physiology and Molecular Genetics, Universidad Rey Juan Carlos, Alcorcón, Spain
| | - Ana M. Briones
- Department of Pharmacology, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Mercedes Salaices
- Department of Pharmacology, School of Medicine, Universidad Autónoma de Madrid, Madrid, Spain
| | - Dalton V. Vassallo
- Department of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES, Brazil
| | - Giulia A. Wiggers
- Postgraduate Program in Biochemistry, Universidade Federal do Pampa, Uruguaiana, RS, Brazil
- * E-mail:
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15
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Toxic effects of mercury on the cardiovascular and central nervous systems. J Biomed Biotechnol 2012; 2012:949048. [PMID: 22811600 PMCID: PMC3395437 DOI: 10.1155/2012/949048] [Citation(s) in RCA: 175] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/15/2012] [Indexed: 12/15/2022] Open
Abstract
Environmental contamination has exposed humans to various metal agents, including mercury. This exposure is more common than expected, and the health consequences of such exposure remain unclear. For many years, mercury was used in a wide variety of human activities, and now, exposure to this metal from both natural and artificial sources is significantly increasing. Many studies show that high exposure to mercury induces changes in the central nervous system, potentially resulting in irritability, fatigue, behavioral changes, tremors, headaches, hearing and cognitive loss, dysarthria, incoordination, hallucinations, and death. In the cardiovascular system, mercury induces hypertension in humans and animals that has wide-ranging consequences, including alterations in endothelial function. The results described in this paper indicate that mercury exposure, even at low doses, affects endothelial and cardiovascular function. As a result, the reference values defining the limits for the absence of danger should be reduced.
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16
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Furieri LB, Fioresi M, Junior RFR, Bartolomé MV, Fernandes AA, Cachofeiro V, Lahera V, Salaices M, Stefanon I, Vassallo DV. Exposure to low mercury concentration in vivo impairs myocardial contractile function. Toxicol Appl Pharmacol 2011; 255:193-9. [PMID: 21723307 DOI: 10.1016/j.taap.2011.06.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 06/06/2011] [Accepted: 06/10/2011] [Indexed: 11/30/2022]
Abstract
Increased cardiovascular risk after mercury exposure has been described but cardiac effects resulting from controlled chronic treatment are not yet well explored. We analyzed the effects of chronic exposure to low mercury concentrations on hemodynamic and ventricular function of isolated hearts. Wistar rats were treated with HgCl₂ (1st dose 4.6 μg/kg, subsequent dose 0.07 μg/kg/day, im, 30 days) or vehicle. Mercury treatment did not affect blood pressure (BP) nor produced cardiac hypertrophy or changes of myocyte morphometry and collagen content. This treatment: 1) in vivo increased left ventricle end diastolic pressure (LVEDP) without changing left ventricular systolic pressure (LVSP) and heart rate; 2) in isolated hearts reduced LV isovolumic systolic pressure and time derivatives, and β-adrenergic response; 3) increased myosin ATPase activity; 4) reduced Na+-K+ ATPase (NKA) activity; 5) reduced protein expression of SERCA and phosphorylated phospholamban on serine 16 while phospholamban expression increased; as a consequence SERCA/phospholamban ratio reduced; 6) reduced sodium/calcium exchanger (NCX) protein expression and α-1 isoform of NKA, whereas α-2 isoform of NKA did not change. Chronic exposure for 30 days to low concentrations of mercury does not change BP, heart rate or LVSP but produces small but significant increase of LVEDP. However, in isolated hearts mercury treatment promoted contractility dysfunction as a result of the decreased NKA activity, reduction of NCX and SERCA and increased PLB protein expression. These findings offer further evidence that mercury chronic exposure, even at small concentrations, is an environmental risk factor affecting heart function.
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Affiliation(s)
- Lorena Barros Furieri
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
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17
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Wiggers GA, Stefanon I, Padilha AS, Peçanha FM, Vassallo DV, Oliveira EM. Low nanomolar concentration of mercury chloride increases vascular reactivity to phenylephrine and local angiotensin production in rats. Comp Biochem Physiol C Toxicol Pharmacol 2008; 147:252-60. [PMID: 18093879 DOI: 10.1016/j.cbpc.2007.10.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 10/21/2007] [Accepted: 10/22/2007] [Indexed: 11/29/2022]
Abstract
Exposure to mercury at nanomolar level affects cardiac function but its effects on vascular reactivity have yet to be investigated. Pressor responses to phenylephrine (PHE) were investigated in perfused rat tail arteries before and after treatment with 6 nM HgCl2 during 1 h, in the presence (E+) and absence (E-) of endothelium, after L-NAME (10(-4) M), indomethacin (10(-5 )M), enalaprilate (1 microM), tempol (1 microM) and deferoxamine (300 microM) treatments. HgCl2 increased sensitivity (pD2) without modifying the maximum response (Emax) to PHE, but the pD2 increase was abolished after endothelial damage. L-NAME treatment increased pD2 and Emax. However, in the presence of HgCl2, this increase was smaller, and it did not modify Emax. After indomethacin treatment, the increase of pD2 induced by HgCl2 was maintained. Enalaprilate, tempol and deferoxamine reversed the increase of pD2 evoked by HgCl2. HgCl2 increased the angiotensin converting enzyme (ACE) activity explaining the result obtained with enalaprilate. Results suggest that at nanomolar concentrations HgCl2 increase the vascular reactivity to PHE. This response is endothelium mediated and involves the reduction of NO bioavailability and the action of reactive oxygen species. The local ACE participates in mercury actions and depends on the angiotensin II generation.
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18
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Machado AC, Padilha AS, Wiggers GA, Siman FDM, Stefanon I, Vassallo DV. Small doses of mercury increase arterial pressure reactivity to phenylephrine in rats. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2007; 24:92-97. [PMID: 21783795 DOI: 10.1016/j.etap.2007.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2005] [Accepted: 02/12/2007] [Indexed: 05/31/2023]
Abstract
Mercury reduces cardiac contractility and arterial pressure at micromolar concentrations. We investigated the actions of 680ng/kg HgCl(2) on arterial pressure, heart rate (HR) and on the pressor reactivity to phenylephrine (PHE) in rats before and 1h after HgCl(2) administration and after hexametonium, verapamil and tempol treatments. HgCl(2) increased baseline systolic (SAP) and diastolic pressure (DAP) and HR, sensitivity (pD(2)) and maximal response (E(max)) to PHE pressor reactivity. Hexametonium and verapamil reduced baseline pressures and HR that increased after HgCl(2) treatment. Hexametonium did not change pD(2) or E(max) to PHE but verapamil reduced them. These parameters increased after HgCl(2) administration. Tempol did not alter baseline pressures, HR or PHE reactivity before and after HgCl(2). Results suggest that HgCl(2) increases SAP, DAP, HR and PHE reactivity; autonomic reflexes reduces HgCl(2) action; baseline pressure level do not interfere on HgCl(2) pressor effects but free radicals seems to be involved.
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Affiliation(s)
- Adriana Caiado Machado
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
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19
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Falcochio D, Assis GPSD, Stefanon I, Vassallo DV. Small concentrations of mercury enhances positive inotropic effects in the rat ventricular myocardium. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 20:22-25. [PMID: 21783563 DOI: 10.1016/j.etap.2004.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 09/30/2004] [Indexed: 05/31/2023]
Abstract
Small concentrations of mercury reduce the force development of the rat right myocardium and inhibit the sodium pump. This inhibition might increase the amount of activator Ca(2+) in the sarcoplasmic reticulum available upon activation. We further investigated whether this action could potentiate positive inotropic effects produced by Ca(2+) increment (0.62-1.25mM) and isoproterenol (20nM). Right ventricular strips contracting isometrically were treated with 0.1 and 1μM HgCl(2). Results showed that after HgCl(2) treatment the magnitude of both inotropic interventions was increased. Considering that Hg(2+) amongst its effects induces hypertension and might be associated with cardiovascular diseases these potentiating effects might have hazardous consequences.
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Affiliation(s)
- Diego Falcochio
- Departments of Physiological Sciences, CBM/UFES, Av. Marechal Campos 1468, 29040-090 Vitória, ES, Brazil
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20
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Abstract
There is increasing concern regarding methylmercury exposure in populations that consume large amounts of fish. This situation poses a dilemma for those who choose to consume fish for its beneficial effects on heart disease risk. Recent evidence suggests that high mercury content in fish may diminish the cardioprotective effect of fish intake. We explore the current knowledge of Hg toxicity on the heart and evaluate the epidemiologic evidence to date.
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Affiliation(s)
- Hing Man Chan
- Centre for Indigenous Peoples' Nutrition and Environment, School of Dietetics and Human Nutrition, McGill University, 21,111 Lakeshore Rd., Ste-Anne-de-Bellevue, QC, Canada H9X 3V9
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21
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Golpon HA, Püchner A, Barth P, Welte T, Wichert PV, Feddersen CO. Nitric oxide-dependent vasorelaxation and endothelial cell damage caused by mercury chloride. Toxicology 2003; 192:179-88. [PMID: 14580785 DOI: 10.1016/s0300-483x(03)00303-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mercury and its derivatives are known to constrict vascular smooth muscle cells. However, little is known about the role of endothelial cells in mercury-induced vasoreactivity. Using isolated, norepinephrine preconstricted rat aorta and pulmonary artery rings with intact endothelium, we demonstrate that mercury chloride (HgCl2) induces an endothelial-dependent vasorelaxation which was totally blocked by the nitric oxide inhibitor L-NAME. Besides this vasorelaxant effect, treatment with HgCl2 resulted in functional and morphological alterations of the endothelial cells. On aortic rings, endothelial cells were partly lifted from the basal membrane when incubated for 20 min in HgCl2 (10(-7) M)-containing buffer. At a concentration of 10(-6) M, the endothelial cells were completely denuded and acetylcholine vasorelaxation was abolished. Endothelial cell structure and function was preserved by incubating the vessels in HgCl2-containing rat blood instead of buffer. We conclude that HgCl2 induces an endothelial-dependent vasorelaxation and alters structure and function of vascular endothelial cells.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/enzymology
- Aorta, Thoracic/pathology
- Endothelial Cells/drug effects
- Endothelial Cells/enzymology
- Endothelial Cells/pathology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/pathology
- Enzyme Inhibitors/pharmacology
- In Vitro Techniques
- Male
- Mercuric Chloride/toxicity
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/pathology
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide Synthase/antagonists & inhibitors
- Pulmonary Artery/drug effects
- Pulmonary Artery/enzymology
- Pulmonary Artery/pathology
- Rats
- Rats, Sprague-Dawley
- Vasodilation/drug effects
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Affiliation(s)
- Heiko A Golpon
- Department of Internal Medicine, Philipps University of Marburg, Baldinger Strasse, 35033 Marburg, Germany.
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22
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de Assis GPS, Silva CEC, Stefanon I, Vassallo DV. Effects of small concentrations of mercury on the contractile activity of the rat ventricular myocardium. Comp Biochem Physiol C Toxicol Pharmacol 2003; 134:375-83. [PMID: 12643984 DOI: 10.1016/s1532-0456(03)00005-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Personal exposure to mercury vapor and the release of mercury from or during removal of amalgam dental fillings increases its blood and plasma concentration. However, it is not known if these very small amounts affect cardiac function. The effects of continuous exposure to 5 and 20 nM of HgCl(2) on the cardiac contractility were investigated in isometric and tetanic contractions of right ventricular strips and in Langendorff perfused rat hearts. The continuous exposure for 2 h produced a small but significant reduction of the isometric twitch force and time to peak tension shortened. Relative post-rest potentiation was not affected by this concentration of HgCl(2) suggesting a lack of action of the metal on the sarcoplasmic reticulum activity. Tetanic tension, in contrast to twitch force, was intensively reduced suggesting an important depressant action on the activity of contractile proteins. In perfused hearts beating spontaneously, isovolumic systolic pressure reduced progressively and the diastolic pressure increased. Although occurring heart rate reduction, it was similar for both controls and mercury treated hearts. Also, time dependent changes in coronary perfusion pressure were similar to controls. Results suggested that cardiac effects may be observed after continuous exposure to very small concentrations of mercury, probably as a result of the cell capacity to concentrate mercury. These results also indicate that continuous professional exposure to mercury followed by its absorption might have toxicological consequences affecting cardiac function, and being considered hazardous.
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23
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Hales CA, Du HK, Volokhov A, Mourfarrej R, Quinn DA. Aquaporin channels may modulate ventilator-induced lung injury. RESPIRATION PHYSIOLOGY 2001; 124:159-66. [PMID: 11164207 DOI: 10.1016/s0034-5687(00)00193-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Adult Respiratory Distress Syndrome is a disease with functional lung heterogeneity and thus a ventilator-delivered breath may over-distend non-involved areas. In rats we examined ventilator-delivered tidal volume (TV) breaths of 7 and 20 ml/kg on lung water as evidence of lung injury. We examined the role of aquaporins on ventilator-induced lung injury (VILI) by infusing HgCl(2) which inhibits aquaporins by binding cysteine. Wet to dry lung weight ratio (W/D) as evidence of lung water was 4.47+/-0.1 SEM in controls, 4.6+/-0.1 and 5.5+/-0.2 (P<0.05) in rats ventilated at 7 and 20 ml/kg, respectively. Pulmonary artery pressure (PAP) rose from 23+/-1 to 26+/-1 mmHg (P<0.05, n=7) and cardiac output fell from 104+/-2 to 67+/-3 ml/min (P<0.05) in rats ventilated at 20 ml/kg. Left ventricular end diastolic pressure (n=3) was unchanged. Evans Blue dye, an albumin marker, increased from a control 37+/-11 to 97+/-41 mg/g wet lung in TV 20 rats (P<0.05). HgCl(2) infused slowly by tail vein did not significantly raise PAP, but did increase W/D to 6+/-0.2 (P<0.05) in rats ventilated at 20 ml/kg but not at 7 ml/kg. Equimolar cysteine infusions prevented the HgCl(2) from increasing the W/D above that seen with TV 20 ml/kg. Thus ventilation with TV of 20 ml/kg produced a protein-rich lung edema. Aquaporin channels may have a protective effect in VILI.
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Affiliation(s)
- C A Hales
- Department of Medicine (Pulmonary and Critical Care), Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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24
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Rossoni LV, Amaral SM, Vassallo PF, França A, Oliveira EM, Varner KJ, Mill JG, Vassallo DV. Effects of mercury on the arterial blood pressure of anesthetized rats. Braz J Med Biol Res 1999; 32:989-97. [PMID: 10454761 DOI: 10.1590/s0100-879x1999000800009] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The available data suggests that hypotension caused by Hg2+ administration may be produced by a reduction of cardiac contractility or by cholinergic mechanisms. The hemodynamic effects of an intravenous injection of HgCl2 (5 mg/kg) were studied in anesthetized rats (N = 12) by monitoring left and right ventricular (LV and RV) systolic and diastolic pressures for 120 min. After HgCl2 administration the LV systolic pressure decreased only after 40 min (99 +/- 3.3 to 85 +/- 8.8 mmHg at 80 min). However, RV systolic pressure increased, initially slowly but faster after 30 min (25 +/- 1.8 to 42 +/- 1.6 mmHg at 80 min). Both right and left diastolic pressures increased after HgCl2 treatment, suggesting the development of diastolic ventricular dysfunction. Since HgCl2 could be increasing pulmonary vascular resistance, isolated lungs (N = 10) were perfused for 80 min with Krebs solution (continuous flow of 10 ml/min) containing or not 5 microM HgCl2. A continuous increase in pulmonary vascular resistance was observed, suggesting the direct effect of Hg2+ on the pulmonary vessels (12 +/- 0.4 to 29 +/- 3.2 mmHg at 30 min). To examine the interactions of Hg2+ and changes in cholinergic activity we analyzed the effects of acetylcholine (Ach) on mean arterial blood pressure (ABP) in anesthetized rats (N = 9) before and after Hg2+ treatment (5 mg/kg). Using the same amount and route used to study the hemodynamic effects we also examined the effects of Hg2+ administration on heart and plasma cholinesterase activity (N = 10). The in vivo hypotensive response to Ach (0.035 to 10.5 microg) was reduced after Hg2+ treatment. Cholinesterase activity (microM h-1 mg protein-1) increased in heart and plasma (32 and 65%, respectively) after Hg2+ treatment. In conclusion, the reduction in ABP produced by Hg2+ is not dependent on a putative increase in cholinergic activity. HgCl2 mainly affects cardiac function. The increased pulmonary vascular resistance and cardiac failure due to diastolic dysfunction of both ventricles are factors that might contribute to the reduction of cardiac output and the fall in arterial pressure.
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Affiliation(s)
- L V Rossoni
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, Brasil
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25
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Vassallo DV, Moreira CM, Oliveira EM, Bertollo DM, Veloso TC. Effects of mercury on the isolated heart muscle are prevented by DTT and cysteine. Toxicol Appl Pharmacol 1999; 156:113-8. [PMID: 10198276 DOI: 10.1006/taap.1999.8636] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The protective effects of dithiothreitol (DTT, 50 microM) and cysteine (CYS, 100 microM) against toxic effects of HgCl2 (1, 2.5, 5, and 10 microM) were studied in isolated, isometrically contracting rat papillary muscles. Force reduction promoted by Hg2+ was prevented by both DTT and CYS. Also, after both treatments, no significant changes in dF/dt were observed. A progressive reduction in the time to peak tension was observed when increased concentrations of HgCl2 were used after CYS and DTT treatment. This was an indication that the enhancement of calcium release from the sarcoplasmic reticulum produced by mercury was not affected by DTT and CYS. Tetanic contractions were also studied. After treatment with DTT or CYS tetanic tension did not change. No significant reduction of tetanic tension was observed during treatment with 1 microM Hg2+ but its reduction was observed after 5 microM Hg2+. Myosin ATPase activity was also affect by Hg2+, being completely blocked by 1 microM Hg2+ and reduced by 50% with 0.15 microM Hg2+. Full activity was restored by using 500 nM DTT. These findings suggest that several but not all toxic effects of Hg2+ on the mechanical activity of the heart muscle are prevented by protectors of SH groups such as DTT and CYS. The enhancement of the Ca2+ release from the sarcoplasmic reticulum by Hg2+ during activation was not affected by prior treatment with DTT and CYS, suggesting that interactions with SH groups may not be important for the activation of the Ca2+ channel of the sarcoplasmic reticulum.
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Affiliation(s)
- D V Vassallo
- Department of Physiological Sciences, Federal University of Espirito Santo, Vitoria, ES, Brazil
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