title: Environmental exposure to methylmercury is associated with a decrease in nitric oxide production.
abstract: Some studies have recently suggested that mercury (Hg)-exposed populations face increased risks of cardiovascular diseases, and experimental data indicate that such risks might be due to reductions in nitric oxide bioavailability. However, no previous study has examined whether Hg exposure affects plasma nitrite concentrations in humans as an indication of nitric oxide production. Here, we investigated whether there is an association between circulating nitrite and Hg concentrations in whole blood, plasma and hair from an exposed methylmercury (MeHg) population. Hair and blood samples were collected from 238 persons exposed to MeHg from fish consumption. Hg concentrations in plasma (PHg), whole blood (BHg) and hair Hg (HHg) were determined by inductively coupled plasma-mass spectrometry. Mean BHg content was 49.8 +/- 35.2 microg/l, mean PHg was 7.8 +/- 6.9 microg/l and HHg 14.6 +/- 10.6 microg/g. Mean plasma nitrite concentration was 253.2 +/- 105.5 nM. No association was found between plasma nitrite concentration and BHg or HHg concentrations in a univariate model. However, multiple regression models adjusted for gender, age and fish consumption showed a significant association between plasma nitrite and plasma Hg concentration (beta = -0.1, p < 0.001). Our findings constitute preliminary clinical evidence that exposure to MeHg may cause inhibitory effects on the production of endothelial nitric oxide.
authors.affiliation: Department of Clinical, Toxicological and Food Science Analysis, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Kátia Cristina
authors.initials: KC
authors.lastname: de Marco
authors.forename: Carlos J S
authors.initials: CJ
authors.lastname: Passos
authors.forename: Jonas
authors.initials: J
authors.lastname: Sertorio
authors.forename: José Eduardo
authors.initials: JE
authors.lastname: Tanus-Santos
authors.forename: Fernando
authors.initials: F
authors.lastname: Barbosa
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D004781:Environmental Exposure / Q000009:adverse effects*; D005260:Female; D005506:Food Contamination; D006197:Hair / Q000737:chemistry; D006801:Humans; D008297:Male; D008628:Mercury / Q000097:blood; D008767:Methylmercury Compounds / Q000097:blood / Q000633:toxicity*; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000097:blood; D017747:Seafood / Q000633:toxicity
chemical_list: D008767:Methylmercury Compounds; D009573:Nitrites; D009569:Nitric Oxide; D008628:Mercury