BACKGROUND: Stem cell transplantation has shown a great potential in regenerative medicine, however, the poor retention of transplanted mesenchymal stem cells and the low cell survival are two obstacles for the therapeutic effects. Numerous studies have shown that stromal cell-derived factor 1 (SDF-1)-CXCR4/CXCR7 axis exerts a crucial role in the mobilization, migration, and survival of stem cells.
OBJECTIVE: To summarize the worldwide latest research progresses of SDF-1-CXCR4/CXCR7 axis in hypoxic conditions, the settlement of stem cells, and the treatment of ischemic renal injury.
METHODS: The first author searched databases of PubMed and Chinese Journal Full-text for papers concerning SDF-1-CXCR4/CXCR7 axis in stem cell therapy for ischemic kidney injury published from January 2000 to December 2012. The keywords were “stromal cell-derived factor-1, CXCR4, CXCR7, stem cells, ischemia, kidney injury” in English and Chinese. A total of 82 relevant articles were initially retrieved, and 57 of them met the inclusion criteria.
RESULTS AND CONCLUSION: The expression of CXCR4 and CXCR7, which are the two natural receptors for SDF-1, can be up-regulated by both in vitro and in vivo induction of hypoxia. Numerous studies have confirmed that the SDF-1-CXCR4/CXCR7 axis exerts an important role in the mobilization, migration, adhesion, proliferation, survival and paracrine of stem cells. SDF-1 is highly expressed in ischemic organs including kidneys, thus contributing to the migration of the cells with a high expression of CXCR4 to the ischemic organs. Several studies have shown that using anti-CXCR7 neutralizing antibody to reduce the CXCR7 levels in stem cells, the ability of cell adhesion and survival under hypoxic-ischemic conditions declines, suggesting that the effects of CXCR7 in regulating the adhesion and survival ability of stem cells. Therefore, further studies on the biological behaviors (such as cell proliferation, apoptosis, migration, adhesion, paracrine) of SDF-1-CXCR4/CXCR7 axis in stem cells and residential cells in target tissues will improve the effectiveness of stem cell-based therapy, and has important value for the treatment of ischemic renal injury.