Manganese Toxicity Upon Overexposure: a Decade in Review
#MMPMID26231508
O'Neal SL
; Zheng W
Curr Environ Health Rep
2015[Sep]; 2
(3
): 315-28
PMID26231508
show ga
Exposure to manganese (Mn) causes clinical signs and symptoms resembling, but not
identical to, Parkinson's disease. Since our last review on this subject in 2004,
the past decade has been a thriving period in the history of Mn research. This
report provides a comprehensive review on new knowledge gained in the Mn research
field. Emerging data suggest that beyond traditionally recognized occupational
manganism, Mn exposures and the ensuing toxicities occur in a variety of
environmental settings, nutritional sources, contaminated foods, infant formulas,
and water, soil, and air with natural or man-made contaminations. Upon fast
absorption into the body via oral and inhalation exposures, Mn has a relatively
short half-life in blood, yet fairly long half-lives in tissues. Recent data
suggest Mn accumulates substantially in bone, with a half-life of about 8-9 years
expected in human bones. Mn toxicity has been associated with dopaminergic
dysfunction by recent neurochemical analyses and synchrotron X-ray fluorescent
imaging studies. Evidence from humans indicates that individual factors such as
age, gender, ethnicity, genetics, and pre-existing medical conditions can have
profound impacts on Mn toxicities. In addition to body fluid-based biomarkers,
new approaches in searching biomarkers of Mn exposure include Mn levels in
toenails, non-invasive measurement of Mn in bone, and functional alteration
assessments. Comments and recommendations are also provided with regard to the
diagnosis of Mn intoxication and clinical intervention. Finally, several hot and
promising research areas in the next decade are discussed.
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