title: Seasonal mercury exposure and oxidant-antioxidant status of James Bay sport fishermen.
abstract: The effects of a moderate seasonal exposure to methylmercury on plasma low-density lipoprotein (LDL) oxidation and cardiovascular risk indices are not known. The objective of the study was to assess the effects of a seasonal exposure to mercury at similar dose reported to increase cardiovascular risk through fish consumption. Effects on lipoprotein cholesterol and fatty acid profiles, LDL oxidation, and blood oxidant-antioxidant balance were to be assessed in sport fishermen presenting normal blood selenium and omega-3 fatty acid contents. Thirty-one healthy James Bay sport fishermen were assessed for within-subject longitudinal seasonal variations in hair and blood mercury, plasma oxidized LDL, lipophilic antioxidants, homocysteine, blood selenium, and glutathione peroxidase and reductase activities determined before and after the fishing season and compared by matched-pair tests. Hair mercury doubled during the fishing season (2.8+/-0.4 microg/g, P<.0001). Baseline blood selenium, homocysteine, and erythrocyte fatty acid profiles did not change. Plasma high-density lipoprotein cholesterol increased (+5%, P=.05), whereas very low-density lipoprotein cholesterol and oxidized LDL decreased (-8%, P=.05; -18%, P=.008). Blood glutathione peroxidase (+9.7%, P=.001), glutathione reductase (+7.2%, P<.0001), and total glutathione (+45% P<.0001) increased during the fishing season. Plasma total coenzyme Q10 (+13%, P=.02), ubiquinone-10 (+67%, P=.03), and beta-carotene (+46%, P=.01) also increased, whereas vitamin E status was unaffected. Pairwise correlations revealed no association between mercury exposure and any of the biomarkers investigated. In contrast, strong predictors of cardiovascular risk such as high-density lipoprotein cholesterol, oxidized LDL, and glutathione peroxidase improved during the fishing season despite elevated methylmercury exposure. The beneficial effects of seasonal fishing activity and fish consumption on cardiovascular health may suppress detrimental effects of concomitant moderate methylmercury exposure.
authors.affiliation: Québec Lipid Research Centre, CHUL Research Centre, Centre Hospitalier Universitaire de Québec, Québec City, Québec, Canada G1V 4G2.
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Bélanger
authors.forename: Marc-Edouard
authors.initials: ME
authors.lastname: Mirault
authors.forename: Eric
authors.initials: E
authors.lastname: Dewailly
authors.forename: Michel
authors.initials: M
authors.lastname: Plante
authors.forename: Line
authors.initials: L
authors.lastname: Berthiaume
authors.forename: Micheline
authors.initials: M
authors.lastname: Noël
authors.forename: Pierre
authors.initials: P
authors.lastname: Julien
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism*; D005398:Fisheries; D006801:Humans; D008077:Lipoproteins, LDL / Q000097:blood / Q000378:metabolism; D008297:Male; D008767:Methylmercury Compounds / Q000633:toxicity*; D008875:Middle Aged; D016273:Occupational Exposure; D012621:Seasons; D024505:Tocopherols / Q000097:blood; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D000975:Antioxidants; D008077:Lipoproteins, LDL; D008767:Methylmercury Compounds; C099252:oxidized low density lipoprotein; D014451:Ubiquinone; C024989:coenzyme Q10; C025204:Ubiquinone Q2; D024505:Tocopherols