Cardiovascular effects of nickel in ambient air.
BACKGROUND
Fine particulate matter (FPM) in ambient air causes premature mortality due to cardiac disease in susceptible populations.


OBJECTIVE
Our objective in this study was to determine the most influential FPM components.


METHODS
A mouse model of atherosclerosis (ApoE-/-) was exposed to either filtered air or concentrated FPM (CAPs) in Tuxedo, New York (85 microg/m3 average, 6 hr/day, 5 days/week, for 6 months), and the FPM elemental composition was determined for each day. We also examined associations between PM components and mortality for two population studies: National Mortality and Morbidity Air Pollution Study (NMMAPS) and Hong Kong.


RESULTS
For the CAPs-exposed mice, the average of nickel was 43 ng/m3, but on 14 days, there were Ni peaks at approximately 175 ng/m3 and unusually low FPM and vanadium. For those days, back-trajectory analyses identified a remote Ni point source. Electrocardiographic measurements on CAPs-exposed and sham-exposed mice showed Ni to be significantly associated with acute changes in heart rate and its variability. In NMMAPS, daily mortality rates in the 60 cities with recent speciation data were significantly associated with average Ni and V, but not with other measured species. Also, the Hong Kong sulfur intervention produced sharp drops in sulfur dioxide, Ni, and V, but not other components, corresponding to the intervention-related reduction in cardiovascular and pulmonary mortality.


CONCLUSIONS
Known biological mechanisms cannot account for the significant associations between Ni with the acute cardiac function changes in the mice or with cardiovascular mortality in people at low ambient air concentrations; therefore, further research is needed.
Lippmann
Morton
M
New York University School of Medicine, Nelson Institute of Environmental Medicine, Tuxedo, New York 10987, USA. lippmann@env.med.nyu.edu
Ito
Kazuhiko
K
Hwang
Jing-Shiang
JS
Maciejczyk
Polina
P
Chen
Lung-Chi
LC
D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D001161:Arteriosclerosis / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D009026:Mortality; D009532:Nickel / Q000633:toxicity*; D052638:Particulate Matter / Q000633:toxicity*
D000393:Air Pollutants; D001057:Apolipoproteins E; D052638:Particulate Matter; D009532:Nickel