Conditioned medium from renal tubular epithelial cells stimulated by hypoxia influences rat bone marrow-derived endothelial progenitor cells.
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.
Wang
Dai-hong
DH
Department of Nephrology, Xinqiao Hospital, Chongqing, PR China.
Li
Fu-rong
FR
Zhang
Ying
Y
Wang
Yi-qin
YQ
Yuan
Fa-huan
FH
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*
D017077:Culture Media, Conditioned