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Evidence-Based Complementary and Alternative Medicine
Volume 2013, Article ID 370961, 9 pages
http://dx.doi.org/10.1155/2013/370961
Research Article

Reconstitution of Kidney Side Population Cells after Ischemia-Reperfusion Injury by Self-Proliferation and Bone Marrow-Derived Cell Homing

1Department of Nephrology, Xijing Hospital, The Fourth Military Medical University, Xi’an 710032, China
2PLA Center of General Surgery, General Hospital of Chengdu Army Region, Chengdu 610083, China
3School of Pharmacy, Fourth Military Medical University, Xi'an 710032, China
4Department of Hepatobiliary Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an 710032, China
5Foreign Language Department, Bethune Military Medical NCO’s Academy, Shijiazhuang 050081, China

Received 29 October 2012; Accepted 16 May 2013

Academic Editor: Yueh-Sheng Chen

Copyright © 2013 Hongbao Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The aim of this study was to examine the contribution of side population (SP) cells from kidney and bone marrow for reconstitution of kidney SP pools after ischemia-reperfusion injury (IRI). The SP and non-SP cells in kidneys following IRI were isolated and serially assessed by fluorescence-activated cell sorting. The apoptosis, proliferation, phenotype, and paracrine actions of SP cells were evaluated in vitro and in vivo. Results indicated that the SP cells from ischemic kidney were acutely depleted within one day following renal IRI and were progressively restored to baseline within 7 days after IRI, through both proliferation of remaining kidney SP cells and homing of bone marrow-derived cells to ischemic kidney. Either hypoxia or serum deprivation alone increased apoptosis of SP cells, and a combination of both further aggravated it. Furthermore, hypoxia in vivo and in vitro induced the increase in the secretion of vascular endothelial growth factor, insulin-like growth factor 1, hepatocyte growth factor, and stromal cell-derived factor-1α in kidney SP but not non-SP cells. In summary, these results suggest that following renal IRI, kidney SP cells are acutely depleted and then progressively restored to baseline levels by both self-proliferation and extrarenal source, that is, bone marrow-derived cell homing.