Objective: To determine the quantitive and functional changes of circulating endothelial progenitor cells (EPCs) in dogs with dehydromonocrotaline-induced pulmonary artery hypertension (PAH).
Methods: Dehydromonocrotaline was injected into the canine right ventricle to induce pulmonary hypertension. Circulating EPCs were enumerated as AC+(113), KDR+ cells by fluorescence-activated cell sorter using counting beads, and the number and activity of EPCs after in vitro expansion were determined by acLDL uptake/lectin staining assay and in vitro tubule forming assay.
Results: Nine of the 10 beagles survived after dehydromonocrotaline injection. Six weeks later, mean pulmonary artery pressure increased from (11.3 +/- 2.0) mm Hg (1 mm Hg = 0.133 kPa) to (20.2 +/- 1.6) mm Hg (t =10.307, P < 0.01), and the AC+(133) and KDR+ cells decreased from (632.8 +/- 42.8) cells/ml to (206.1 +/- 26.8) cells/ml (t = 25.361, P < 0.01). UEA- I and DiLDL positive cells deceased from (41 +/- 6) EPCs/ x 200 field to (22 +/- 6) EPCs/ x 200 field (t = 6.510, P < 0.01). In addition, in vasculogenesis assay, PAH EPCs formed less quantitative (11.2 +/- 2.8 vs 21.1 +/- 2.8 tubules/ x 200 field, respectively, t = 7. 583, P <0. 01) and less qualitive tubules than baseline EPCs.
Conclusion: The number and vessel forming ability of EPCs are impaired in this canine model of dehydromonocrotaline-induced pulmonary hypertension.