title: The effect of acute exposure to coarse particulate matter air pollution in a rural location on circulating endothelial progenitor cells: results from a randomized controlled study.
abstract: BACKGROUND
  Fine particulate matter (PM) air pollution has been associated with alterations in circulating endothelial progenitor cell (EPC) levels, which may be one mechanism whereby exposures promote cardiovascular diseases. However, the impact of coarse PM on EPCs is unknown.
  
  
  OBJECTIVE
  We aimed to determine the effect of acute exposure to coarse concentrated ambient particles (CAP) on circulating EPC levels.
  
  
  METHODS
  Thirty-two adults (25.9 ± 6.6 years) were exposed to coarse CAP (76.2 ± 51.5 μg m(-3)) in a rural location and filtered air (FA) for 2 h in a randomized double-blind crossover study. Peripheral venous blood was collected 2 and 20 h post-exposures for circulating EPC (n = 21), white blood cell (n = 24) and vascular endothelial growth factor (VEGF) (n = 16-19) levels. The changes between exposures were compared by matched Wilcoxon signed-rank tests.
  
  
  RESULTS
  Circulating EPC levels were elevated 2 [108.29 (6.24-249.71) EPC mL(-1); median (25th-75th percentiles), p = 0.052] and 20 h [106.86 (52.91-278.35) EPC mL(-1), p = 0.008] post-CAP exposure compared to the same time points following FA [38.47 (0.00-84.83) and 50.16 (0.00-104.79) EPC mL(-1)]. VEGF and white blood cell (WBC) levels did not differ between exposures.
  
  
  CONCLUSIONS
  Brief inhalation of coarse PM from a rural location elicited an increase in EPCs that persisted for at least 20 h. The underlying mechanism responsible may reflect a systemic reaction to an acute "endothelial injury" and/or a circulating EPC response to sympathetic nervous system activation.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48106, USA. robdbrok@umich.edu
authors.forename: Robert D
authors.initials: RD
authors.lastname: Brook
authors.forename: Robert L
authors.initials: RL
authors.lastname: Bard
authors.forename: Mariana J
authors.initials: MJ
authors.lastname: Kaplan
authors.forename: Srilakshmi
authors.initials: S
authors.lastname: Yalavarthi
authors.forename: Masako
authors.initials: M
authors.lastname: Morishita
authors.forename: J Timothy
authors.initials: JT
authors.lastname: Dvonch
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.forename: Hui-Yu
authors.initials: HY
authors.lastname: Yang
authors.forename: Catherine
authors.initials: C
authors.lastname: Spino
authors.forename: Bhramar
authors.initials: B
authors.lastname: Mukherjee
authors.forename: Elif A
authors.initials: EA
authors.lastname: Oral
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Sun
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brook
authors.forename: Jack
authors.initials: J
authors.lastname: Harkema
authors.forename: Sanjay
authors.initials: S
authors.lastname: Rajagopalan
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D042783:Endothelial Cells; D005260:Female; D006801:Humans; D008297:Male; D010316:Particle Size; D052638:Particulate Matter / Q000737:chemistry / Q000633:toxicity*; D012424:Rural Population; D013234:Stem Cells; D055815:Young Adult
chemical_list: D052638:Particulate Matter
references.citation: Environ Health Perspect. 2009 Nov;117(11):1697-701
references.pmid: 20049120
references.citation: Cytometry A. 2009 Jan;75(1):25-37
references.pmid: 19009636
references.citation: Circ Res. 2013 Mar 29;112(7):1026-34
references.pmid: 23418295
references.citation: Eur Respir J. 2005 Aug;26(2):309-18
references.pmid: 16055881
references.citation: Res Rep Health Eff Inst. 2004 Aug;(120):1-68; discussion 69-79
references.pmid: 15543855
references.citation: Arterioscler Thromb Vasc Biol. 2010 Jun;30(6):1088-93
references.pmid: 20453167
references.citation: Lancet. 2012 Dec 15;380(9859):2224-60
references.pmid: 23245609
references.citation: Blood. 2007 Oct 15;110(8):2907-15
references.pmid: 17638846
references.citation: Circulation. 2010 Jun 1;121(21):2331-78
references.pmid: 20458016
references.citation: Arterioscler Thromb Vasc Biol. 2011 Jul;31(7):1598-606
references.pmid: 21527748
references.citation: Hypertension. 2009 Sep;54(3):659-67
references.pmid: 19620518
references.citation: Circulation. 2011 Jul 19;124(3):346-54
references.pmid: 21768552
references.citation: Environ Health Perspect. 2009 Jun;117(6):898-903
references.pmid: 19590680
references.citation: JAMA. 2008 May 14;299(18):2172-9
references.pmid: 18477784
references.citation: Ther Adv Cardiovasc Dis. 2008 Jun;2(3):199-213
references.pmid: 19124422
references.citation: Circ Res. 2012 Feb 17;110(4):624-37
references.pmid: 22343557
references.citation: J Am Coll Cardiol. 2007 Feb 20;49(7):741-52
references.pmid: 17306702
references.citation: Biostatistics. 2011 Oct;12(4):637-52
references.pmid: 21297159
references.citation: Inhal Toxicol. 2010 Dec;22 Suppl 2:95-9
references.pmid: 20936915
references.citation: Blood. 2004 May 15;103(10):3677-83
references.pmid: 14726373
references.citation: J Am Coll Cardiol. 2008 May 6;51(18):1760-71
references.pmid: 18452782
references.citation: Environ Health Perspect. 2012 Jun;120(6):848-56
references.pmid: 22418586
references.citation: Circ Res. 2010 Jul 23;107(2):200-3
references.pmid: 20595651