title: Conditioned medium from renal tubular epithelial cells stimulated by hypoxia influences rat bone marrow-derived endothelial progenitor cells.
abstract: OBJECTIVE
  It has been well documented that endothelial progenitor cells (EPCs) participate in neovascularization in adults and that rarefaction of peritubular capillaries (PTCs) is closely associated with progressive kidney disease. Therefore, we investigated whether EPCs were influenced by conditioned medium (CM) of renal tubular epithelial cells (RTECs) stimulated by hypoxia, to provide evidence for EPCs transplantation in vivo in the future.
  
  
  METHODS
  Mononuclear cells of rat bone marrow were isolated by density gradient centrifugation and were cultured according to previously described techniques. RTECs were cultured primarily with routine tissue block adhering wall method. In addition, CM was harvested from RTECs cultivated for 48 h in 5% O(2). EPCs proliferation and migration were evaluated by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and transwell. The protein and mRNA expression of stromal cell-derived factor (SDF-1), vascular endothelial growth factor (VEGF), angiogenin 1 (Ang-1), and C-X-C chemokine receptor 4 (CXCR4) was separately assessed by Western blot, enzyme-linked immunosorbent assay (ELISA), and reverse transcriptase-polymerase chain reaction (RT-PCR) methods.
  
  
  RESULTS
  We showed that hypoxia increased the expression of SDF-1 and VEGF in RTEC. In addition, hypoxic CM improved proliferation, migration, and expression of VEGF, Ang-1, and CXCR4 of EPCs.
  
  
  CONCLUSIONS
  These results suggest that hypoxic CM improves neovascularization of EPCs and may also be considered as therapeutic agents to supply the potent origin of reconstituion of PTCs of progressive kidney disease.
authors.affiliation: Department of Nephrology, Xinqiao Hospital, Chongqing, PR China.
authors.forename: Dai-hong
authors.initials: DH
authors.lastname: Wang
authors.forename: Fu-rong
authors.initials: FR
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yi-qin
authors.initials: YQ
authors.lastname: Wang
authors.forename: Fa-huan
authors.initials: FH
authors.lastname: Yuan
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000187:drug effects* / Q000502:physiology*; D015687:Cell Hypoxia; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000493:pharmacokinetics; D004847:Epithelial Cells / Q000187:drug effects* / Q000502:physiology*; D007684:Kidney Tubules / Q000166:cytology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013234:Stem Cells / Q000187:drug effects* / Q000502:physiology*
chemical_list: D017077:Culture Media, Conditioned