title: Increased expression of stem cell factor and its receptor after left ventricular assist device support: a potential novel target for therapeutic interventions in heart failure.
abstract: BACKGROUND
  Left ventricular assist devices (LVADs) cause an influx of mast cells into the failing heart, but the underlying mechanism is unknown. This study investigates the potential role of stem cell factor (SCF) and its receptor (c-Kit) in promoting the recruitment of mast cells during heart failure and after LVAD support.
  
  
  METHODS
  Myocardial samples were collected from 10 end-stage heart failure patients undergoing LVAD implantation (pre-LVAD) and paired with samples taken at the time of orthotopic heart transplantation (post-LVAD). Biopsies of normal hearts served as controls. We assessed gene expression of SCF and c-Kit. In addition, we stained for SCF, c-Kit, tryptase and chymase, and utilized in situ hybridization to determine the origin of SCF.
  
  
  RESULTS
  SCF mRNA and overall mast cell numbers were significantly increased (p < 0.01/p < 0.001) after LVAD support as compared with paired heart failure tissues. c-Kit mRNA was significantly increased post-LVAD compared with normal tissues (p < 0.05). The c-Kit protein was expressed only in cardiac mast cells. SCF mRNA was found in endothelial cells, myocytes and interstitial cells, as confirmed by antibody staining.
  
  
  CONCLUSIONS
  LVADs cause an increase of SCF and c-Kit gene expression, which coincides with a surge of mast cells after ventricular unloading. This suggests that SCF functions as an important mediator for the recruitment of mast cells to the mechanically unloaded human heart.
authors.affiliation: Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas 77030, USA. jahanyar@bcm.tmc.edu
authors.forename: Jama
authors.initials: J
authors.lastname: Jahanyar
authors.forename: Keith A
authors.initials: KA
authors.lastname: Youker
authors.forename: Guillermo
authors.initials: G
authors.lastname: Torre-Amione
authors.forename: Michael M
authors.initials: MM
authors.lastname: Koerner
authors.forename: Brian
authors.initials: B
authors.lastname: Bruckner
authors.forename: George P
authors.initials: GP
authors.lastname: Noon
authors.forename: Matthias
authors.initials: M
authors.lastname: Loebe
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005260:Female; D015870:Gene Expression; D006333:Heart Failure / Q000378:metabolism* / Q000628:therapy; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D008875:Middle Aged; D019009:Proto-Oncogene Proteins c-kit / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019089:Stem Cell Factor / Q000096:biosynthesis*
chemical_list: D019089:Stem Cell Factor; D019009:Proto-Oncogene Proteins c-kit