Exposure to low mercury concentration in vivo impairs myocardial contractile function

Furieri, Lorena Barros; Fioresi, Mirian; Ribeiro, Rogério Faustino; Bartolomé, María Visitación; Fernandes, Aurélia Araújo; Cachofeiro, Victoria; Lahera, Vicente; Salaíces, Mercedes; Stefanon, Ivanita; Vassallo, Dalton Valentim

doi:10.1016/j.taap.2011.06.015

Cited by 27 publications

(33 citation statements)

References 36 publications

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“…As previously described, this treatment led to HgCl 2 blood levels of approximately 8 ng/mL [20], [21], [23]. In the present study this was considered as low dose of HgCl 2 instead of a toxic dose because our treatment attained to a blood mercury content of 8 ng/ml, that is close to the levels observed in exposed humans [24], [25].…”

Section: Methodssupporting

confidence: 72%

“…Moreover, chronic low doses of mercury chloride (HgCl 2 ) also have an deleterious effect on coronary artery function by producing an increasing resistance to blood flow that might cause contraction and relaxation impairment under vascular overload conditions [20]. In the isolated, perfused heart, chronic exposure to mercury induces alterations in calcium handling mechanisms, such as a reduction in NCX and SERCA expression and the induction of negative inotropic effect [21].…”

Section: Introductionmentioning

confidence: 99%

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Chronic Exposure to Low Doses of HgCl2 Avoids Calcium Handling Impairment in the Right Ventricle after Myocardial Infarction in Rats

et al. 2014

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Right ventricle systolic dysfunction is a major risk factor for death and heart failure after myocardial infarction (MI). Heavy metal exposure has been associated with the development of several cardiovascular diseases, such as MI. The aim of this study was to investigate whether chronic exposure to low doses of mercury chloride (HgCl2) enhances the functional deterioration of right ventricle strips after MI. Male Wistar rats were divided into four groups: Control (vehicle); HgCl2 (exposure during 4 weeks- 1st dose 4.6 µg/kg, subsequent dose 0.07 µg/kg/day, i.m. to cover daily loss); MI surgery induced and HgCl2-MI groups. One week after MI, the morphological and hemodynamic measurements and isometric tension of right ventricle strips were investigated. The chronic HgCl2 exposure did not worsen the injury compared with MI alone in the morphological or hemodynamic parameters evaluated. At basal conditions, despite similar maximum isometric force at L-max, relaxation time was increased in the MI group but unaffected in the HgCl2-MI compared to the Control group. Impairment of the sarcoplasmic reticulum (SR) function and reduction in the sarcolemmal calcium influx were observed in MI group associated with SERCA2a reduction and increased PLB protein expression. Induction of MI in chronic HgCl2 exposed rats did not cause any alteration in the developed force at L-max, lusitropic function or −dF/dt except for a tendency of a reduction SR function. These findings could be partially explained by the normalization in the sarcolemmal calcium influx and the increase in NCX protein expression observed only in this group. These results suggest that chronic exposure to low doses of HgCl2 prevents the impaired SR function and the reduced sarcolemmal calcium influx observed in MI likely by acting on NCX, PLB and SERCA2a protein expression.

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Section: Methodssupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Chronic Exposure to Low Doses of HgCl2 Avoids Calcium Handling Impairment in the Right Ventricle after Myocardial Infarction in Rats

et al. 2014

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“…Moreover, this treatment promoted contractility dysfunction as a result of reduced Na + /K + -ATPase activity, decreased sarco/endoplasmic reticulum Ca 2+ -ATPase and sodium/calcium exchanger and increased phospholamban protein expression in isolated (Langendorff perfused) hearts of the exposed rats. In the chronically treated animals blood pressure, heart rate and left ventricular systolic pressure were not affected, whereas left ventricular and diastolic pressure was slightly but statistically significantly increased (Furieri et al, 2011b). …”

Section: Mechanisms Of Vascular/cardiovascular Toxicitymentioning

confidence: 92%

Scientific Opinion on the risk for public health related to the presence of mercury and methylmercury in food

2012

EFS2

465

160

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EFSA was asked by the European Commission to consider new developments regarding inorganic mercury and methylmercury toxicity and evaluate whether the Joint FAO/WHO Expert Committee on Food Additives (JECFA) provisional tolerable weekly intakes for methylmercury of 1.6 µg/kg body weight (b.w.) and of 4 µg/kg b.w. for inorganic mercury were still appropriate. In line with JECFA, the CONTAM Panel established a tolerable weekly intake (TWI) for inorganic mercury of 4 µg/kg b.w., expressed as mercury. For methylmercury, new developments in epidemiological studies from the Seychelles Child Developmental Study Nutrition Cohort have indicated that n-3 long-chain polyunsaturated fatty acids in fish may counteract negative effects from methylmercury exposure. Together with the information that beneficial nutrients in fish may have confounded previous adverse outcomes in child cohort studies from the Faroe Islands, the Panel established a TWI for methylmercury of 1.3 µg/kg b.w., expressed as mercury. The mean dietary exposure across age groups does not exceed the TWI for methylmercury, with the exception of toddlers and other children in some surveys. The 95 th percentile dietary exposure is close to or above the TWI for all age groups. High fish consumers, which might include pregnant women, may exceed the TWI by up to approximately six-fold. Unborn children constitute the most vulnerable group. Biomonitoring data from blood and hair indicate that methylmercury exposure is generally below the TWI in Europe, but higher levels are also observed. Exposure to methylmercury above the TWI is of concern. If measures to reduce methylmercury exposure are considered, the potential beneficial effects of fish consumption should also be taken into account. Dietary inorganic mercury exposure in Europe does not exceed the TWI, but inhalation exposure of elemental mercury from dental amalgam is likely to increase the internal inorganic mercury exposure; thus the TWI might be exceeded. This opinion focuses only on the risks related to dietary inorganic mercury and methylmercury exposure and does not assess the nutritional benefits linked to certain foods (e.g. fish and other seafood).A call for annual collection of chemical contaminant occurrence data in food and feed, including mercury, was issued by EFSA in December 2010. In response, EFSA received 59 820 results on mercury in food from 20 European countries, mainly covering the period from 2004 to 2011. A total number of 59 650 results were described with sufficient detail to be used in the statistical analysis of the respective food groups; 98.2 % of the samples were for total mercury, 1.8 % for methylmercury and three samples for inorganic mercury.All the 20 food groups available at the first level of FoodEx were covered in the current data collection. The food groups 'Fish and other seafood' and 'Meat and meat products' dominated the food product coverage with 36.8 % and 17.6 % respectively. These were followed by 'Grain and grain-based products' at 7.8 % and 'Vegetables an...

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“…15 Although a possible concentration-dependent effect of this metal on the different organs may exist, and reference values for blood mercury levels have already been established, our group have shown adverse effects, including cardiovascular dysfunction, due to exposure at concentrations near or below those considered safe. [16][17][18][19][20][21] To study the chronic effects of mercury exposure, it was previously developed a controlled model of chronic exposure to mercury chloride (HgCl 2 ) for 30 days in the rat. 19 This protocol resulted in blood mercury concentrations of 8 ng mL -1 (29 nM), which is similar to those found in exposed humans.…”

Section: +mentioning

confidence: 99%

Mercury Biodistribution in Rats after Chronic Exposure to Mercury Chloride

Fornazier¹,

Nascimento²,

Marques³

et al. 2018

J. Braz. Chem. Soc.

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This study aimed to evaluate the distribution of mercury in rats after controlled chronic exposure to three different doses of HgCl 2 for 30 days. Samples of blood, brain, liver, testis, heart, and kidneys were collected for mercury determination. Although the rats were exposed to different doses, the Hg levels in blood were similar among the groups under study. However, the distribution of mercury in the organs have substantially differed between low and high doses. There was a significant tendency to high deposition in the liver and kidney. The deposition profile in the tissues suggests that the level of mercury remains relatively low in blood while it is deposited at preferential sites such as liver and kidney, demonstrating that, at least at the doses studied, the screening for Hg exposure is unreliable by blood sample analysis.

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Exposure to low mercury concentration in vivo impairs myocardial contractile function

Cited by 27 publications

References 36 publications

Chronic Exposure to Low Doses of HgCl2 Avoids Calcium Handling Impairment in the Right Ventricle after Myocardial Infarction in Rats

Chronic Exposure to Low Doses of HgCl2 Avoids Calcium Handling Impairment in the Right Ventricle after Myocardial Infarction in Rats

Scientific Opinion on the risk for public health related to the presence of mercury and methylmercury in food

Mercury Biodistribution in Rats after Chronic Exposure to Mercury Chloride

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