title: Associations between platelet monoamine oxidase-B activity and acquired colour vision loss in a fish-eating population.
abstract: Platelet monoamine oxidase-B (MAO-B) has been considered a surrogate biochemical marker of neurotoxicity, as it may reflect changes in the monoaminergic system in the brain. Colour vision discrimination, in part a dopamine dependent process, has been used to identify early neurological effects of some environmental and industrial neurotoxicants. The objective of this cross-sectional study was to explore the relationship between platelet MAO-B activity and acquired colour discrimination capacity in fish-consumers from the St. Lawrence River region of Canada. Assessment of acquired dyschromatopsia was determined using the Lanthony D-15 desaturated panel test. Participants classified with dyschromatopsia (n=81) had significantly lower MAO-B activity when compared to those with normal colour vision (n=32) (26.5+/-9.6 versus 31.0+/-9.9 nmol/min/20 microg, P=0.030)). Similarly, Bowman's Colour Confusion Index (CCI) was inversely correlated with MAO-B activity when the vision test was performed with the worst eye only (r=-0.245, P=0.009), the best eye only (r=-0.188, P=0.048) and with both eyes together (r=-0.309, P=0.001). Associations remained significant after adjustment for age and gender when both eyes (P=0.003) and the worst eye (P=0.045) were tested. Adjustment for heavy smoking weakened the association between MAO-B and CCI in the worst eye (P=0.140), but did not alter this association for both eyes (P=0.006). Adjustment for blood-mercury concentrations did not change the association. This study suggests a relationship between reduced MAO-B activity and acquired colour vision loss and both are associated with tobacco smoking. Therefore, results show that platelet MAO-B may be used as a surrogate biochemical marker of acquired colour vision loss.
authors.affiliation: Centre for Indigenous Peoples' Nutrition and Environment and School of Dietetics and Human Nutrition, McGill University, Ste-Anne-de-Bellevue, QC, Canada H9X 3V9.
authors.forename: Christopher John
authors.initials: CJ
authors.lastname: Stamler
authors.forename: Donna
authors.initials: D
authors.lastname: Mergler
authors.forename: Nadia
authors.initials: N
authors.lastname: Abdelouahab
authors.forename: Claire
authors.initials: C
authors.lastname: Vanier
authors.forename: Hing Man
authors.initials: HM
authors.lastname: Chan
mesh_terms: D000375:Aging; D000818:Animals; D015415:Biomarkers; D001792:Blood Platelets / Q000201:enzymology*; D003117:Color Vision Defects / Q000097:blood / Q000139:chemically induced* / Q000201:enzymology*; D003430:Cross-Sectional Studies; D004032:Diet / Q000009:adverse effects*; D004192:Discrimination, Psychological / Q000187:drug effects; D005260:Female; D005399:Fishes / Q000378:metabolism*; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008460:Meat / Q000009:adverse effects* / Q000032:analysis; D008628:Mercury / Q000009:adverse effects* / Q000097:blood; D008875:Middle Aged; D008995:Monoamine Oxidase / Q000097:blood*; D018570:Risk Assessment
chemical_list: D015415:Biomarkers; D008995:Monoamine Oxidase; D008628:Mercury