title: Azelnidipine, Not Amlodipine, Induces Secretion of Vascular Endothelial Growth Factor From Smooth Muscle Cells and Promotes Endothelial Tube Formation.
abstract: BACKGROUND
  We previously reported that the calcium channel blocker (CCB) nifedipine-induced secretion of vascular endothelial growth factor (VEGF) from human coronary smooth muscle cells (HCSMCs) promoted human coronary endothelial cell (HCEC) tube formation. Therefore, we analyzed whether other CCBs, azelnidipine and amlodipine, also induced the secretion of VEGF and promoted HCEC tube formation, and the underlying molecular mechanisms.
  
  
  METHODS
  To evaluate the tube formation, HCECs were grown on Matrigel for 18 hours in the supernatants from HCSMCs that had been treated with different kinds of reagents. Concentrations of VEGF in cultured HCSMCs were determined by specific enzyme immunoassays. Nuclear extracts from HCSMCs were prepared, and nuclear factor-kappa B (NF-κB) activation was measured by EZ-DetectTMTranscription Factor Kits for NF-κB p50 or p65.
  
  
  RESULTS
  Although azelnidipine dose-dependently stimulated the significant secretion of VEGF from HCSMCs and this stimulation was abolished by a protein kinase C inhibitor, amlodipine-induced secretion of VEGF was significantly lower than that induced by azelnidipine. The medium derived from azelnidipine (at up to 2 μM)-treated HCSMCs led to HCEC tube formation, whereas that obtained with amlodipine did not. Azelnidipine-induced tube formation was blocked by an inhibitor of kinase insert domain-containing receptor/fetal liver kinase-1 tyrosine kinase. Azelnidipine at up to 2 μM induced NF-κB activation.
  
  
  CONCLUSIONS
  Azelnidipine, but not amlodipine, stimulated the secretion of VEGF from HCSMCs and induced HCEC tube formation. This secretion is mediated at least in part via the activation of NF-κB. Azelnidipine may have a novel beneficial effect in improving coronary microvascular blood flow in addition to its main effect of lowering blood pressure.
authors.affiliation: Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kawamura
authors.affiliation: Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan; Department of Molecular Cardiovascular Therapeutics, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
authors.forename: Shin-Ichiro
authors.initials: SI
authors.lastname: Miura
authors.affiliation: Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
authors.forename: Yoshino
authors.initials: Y
authors.lastname: Matsuo
authors.affiliation: Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanigawa
authors.affiliation: Department of Cardiology, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan; Department of Molecular Cardiovascular Therapeutics, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan.
authors.forename: Keijiro
authors.initials: K
authors.lastname: Saku
keywords: Calcium channel blocker; Endothelial cell tube formation; Nuclear factor-kappa B; Smooth muscle cell; Vascular endothelial growth factor