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.
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.
Christopher John
CJ
Stamler
Nadia
N
Abdelouahab
Claire
C
Vanier
Donna
D
Mergler
Hing Man
HM
Chan
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