title: Circulating CD34+ Cell Count is Associated with Extent of Subclinical Atherosclerosis in Asymptomatic Amish Men, Independent of 10-Year Framingham Risk.
abstract: BACKGROUND
  Bone-marrow derived progenitor cells (PCs) may play a role in maintaining vascular health by actively repairing damaged endothelium. The purpose of this study in asymptomatic Old Order Amish men (n = 90) without hypertension or diabetes was to determine if PC count, as determined by CD34+ cell count in peripheral blood, was associated with 10-year risk of cardiovascular disease (CVD) and measures of subclinical atherosclerosis.
  
  
  RESULTS
  CD34+ cell count by fluorescence-activated cell sorting, coronary artery calcification (CAC) by electron beam computed tomography, and CVD risk factors were obtained. Carotid intimal-medial thickness (CIMT) also was obtained in a subset of 57 men. After adjusting for 10-year CVD risk, CD34+ cell count was significantly associated with CAC quantity (p = 0.03) and CIMT (p < 0.0001). A 1-unit increase in natural-log transformed CD34+ cell count was associated with an estimated 55.2% decrease (95% CI: -77.8% to -9.3%) in CAC quantity and an estimated 14.3% decrease (95% CI: -20.1% to -8.1%) in CIMT.
  
  
  CONCLUSIONS
  Increased CD34+ cell count was associated with a decrease in extent of subclinical atherosclerosis in multiple arterial beds, independent of 10-year CVD risk. Further investigations of associations of CD34+ cell count with subclinical atherosclerosis in asymptomatic individuals could provide mechanistic insights into the atherosclerotic process.
authors.affiliation: Department of Epidemiology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Bielak
authors.forename: Richard B
authors.initials: RB
authors.lastname: Horenstein
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Ryan
authors.forename: Patrick F
authors.initials: PF
authors.lastname: Sheedy
authors.forename: John A
authors.initials: JA
authors.lastname: Rumberger
authors.forename: Keith
authors.initials: K
authors.lastname: Tanner
authors.forename: Wendy
authors.initials: W
authors.lastname: Post
authors.forename: Braxton D
authors.initials: BD
authors.lastname: Mitchell
authors.forename: Alan R
authors.initials: AR
authors.lastname: Shuldiner
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Peyser
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