Relationship between platelet monoamine oxidase-B (MAO-B) activity and mercury exposure in fish consumers from the Lake St. Pierre region of Que., Canada.
Mercury (Hg) is a widespread neurotoxic compound that bio-accumulates in fish and marine mammals. Monoamine oxidase (MAO; EC 1.4.3.4) regulates biogenic amine concentration in the brain and peripheral tissue and has been shown to be a molecular target of Hg compounds in animal models. Blood platelet monoamine oxidase-B (MAO-B) activity may reflect MAO function in the central nervous tissue. Therefore, the objective of this study was to evaluate the relationship between platelet MAO-B and Hg exposure in fish-eating adults (n=127) living along the St. Lawrence River (Lake St. Pierre, Que., Canada). Hg concentrations were determined in blood and hair samples. A significant negative association was observed between platelet MAO-B activity and blood-Hg (r=-0.193, p=0.029) but not with hair-Hg levels (r=-0.125, p=0.169). Multiple linear regression analysis demonstrated that blood-Hg (beta=-4.6, p=0.011) and heavy smoking (beta=-8.5, p=0.001) were associated with reduced platelet MAO activity in the total population. In addition, this reduction in MAO-B activity appeared to be associated with blood-Hg concentrations above 3.4 microg/L (75th percentile). Possible gender related differences were also observed and are discussed. Our results suggest that MAO-B activity in blood platelets may be a useful tool to assess biochemical effects of Hg exposure in human populations. These changes in platelet MAO-B may reflect enzymatic changes in nervous tissue and should be further investigated as a surrogate marker of neurotoxicity.
Stamler
Christopher John
CJ
Centre for Indigenous Peoples' Nutrition and Environment (CINE) and the School of Dietetics and Human Nutrition, McGill University, 21, 111 Lakeshore Rd., Ste-Anne-de-Bellevue, Montréal, Que., Canada H9X 3V9.
Abdelouahab
Nadia
N
Vanier
Claire
C
Mergler
Donna
D
Chan
Hing Man
HM
D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D001792:Blood Platelets / Q000201:enzymology*; D002648:Child; D004785:Environmental Pollutants; D005260:Female; D005399:Fishes; D005506:Food Contamination; D006801:Humans; D008297:Male; D008628:Mercury / Q000032:analysis / Q000097:blood* / Q000493:pharmacokinetics; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000097:blood*; D011237:Predictive Value of Tests; D011792:Quebec; D012111:Residence Characteristics / Q000706:statistics & numerical data; D012737:Sex Factors; D013050:Spectrometry, Fluorescence / Q000379:methods
D004785:Environmental Pollutants; D008995:Monoamine Oxidase; D008628:Mercury