Concentrated ambient ultrafine particle exposure induces cardiac changes in young healthy volunteers.
BACKGROUND
Exposure to ambient ultrafine particles has been associated with cardiopulmonary toxicity and mortality. Adverse effects specifically linked to ultrafine particles include loss of sympathovagal balance and altered hemostasis.


OBJECTIVE
To characterize the effects of acute exposure to ambient ultrafine particles in young healthy humans.


METHODS
Nineteen healthy nonsmoking male and female subjects between the ages of 18 and 35 were exposed to filtered air or to an atmosphere in which captured ultrafine (<0.16 microm) particles were concentrated by a factor of up to 20-fold over ambient levels with the use of particle concentrators fitted with size-selective outlets (ultrafine concentrated ambient particles [UFCAPs]). Subjects underwent bronchoalveolar lavage 18 hours after each exposure. Cardiovascular endpoints measured included pulmonary function, clinical chemistry, and hematological parameters, as well as heart rate variability and repolarization indices.


RESULTS
Exposure to UFCAPs was statistically associated with an increase in frequency domain markers of heart rate variability, specifically indicative of elevated vagal input to the heart. Consistent with this finding were increases in the variance associated with the duration of the QT interval. In addition, UFCAP exposure resulted in a significant increase in blood levels of the fibrin degradation product D-dimer as well as a modest elevation in the inflammatory chemokine IL-8 recovered in the lavage fluid.


CONCLUSIONS
These findings show mild inflammatory and prothrombic responses and are suggestive of alterations in cardiac repolarization induced by UFCAP inhalation.
Samet
James M
JM
Human Studies Division, National Health and Environmental Effects Research Laboratory, Research Triangle Park, Chapel Hill, NC 27599-7315, USA. samet.james@epa.gov
Rappold
Ana
A
Graff
Donald
D
Cascio
Wayne E
WE
Berntsen
Jon H
JH
Huang
Yuh-Chin T
YC
Herbst
Margaret
M
Bassett
Maryann
M
Montilla
Tracey
T
Hazucha
Milan J
MJ
Bromberg
Philip A
PA
Devlin
Robert B
RB
D000293:Adolescent; D000328:Adult; D001992:Bronchoalveolar Lavage Fluid; D015331:Cohort Studies; D004562:Electrocardiography; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006339:Heart Rate; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D008297:Male; D052638:Particulate Matter / Q000009:adverse effects*; D055815:Young Adult
D005338:Fibrin Fibrinogen Degradation Products; D016209:Interleukin-8; D052638:Particulate Matter; C036309:fibrin fragment D