Myocardial CXCR4 expression is required for mesenchymal stem cell mediated repair following acute myocardial infarction

Circulation. 2012 Jul 17;126(3):314-24. doi: 10.1161/CIRCULATIONAHA.111.082453. Epub 2012 Jun 9.


Background: Overexpression of stromal cell-derived factor-1 in injured tissue leads to improved end-organ function. In this study, we quantify the local trophic effects of mesenchymal stem cell (MSC) stromal cell-derived factor-1 release on the effects of MSC engraftment in the myocardium after acute myocardial infarction.

Methods and results: Conditional cardiac myocyte CXCR4 (CM-CXCR4) null mice were generated by use of tamoxifen-inducible cardiac-specific cre by crossing CXCR4 floxed with MCM-cre mouse. Studies were performed in littermates with (CM-CXCR4 null) or without (control) tamoxifen injection 3 weeks before acute myocardial infarction. One day after acute myocardial infarction, mice received 100,000 MSC or saline via tail vein. We show α-myosin heavy chain MerCreMer and the MLC-2v promoters are active in cardiac progenitor cells. MSC engraftment in wild-type mice decreased terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling positive CM (-44%, P<0.01), increased cardiac progenitor cell recruitment (100.9%, P<0.01), and increased cardiac myosin-positive area (39%, P<0.05) at 4, 7, and 21 days after acute myocardial infarction, respectively. MSC in wild-type mice resulted in 107.4% (P<0.05) increase in ejection fraction in comparison with 25.9% (P=NS) increase in CM-CXCR4 null mice. These differences occurred despite equivalent increases (16%) in vascular density in response to MSC infusion in wild-type and CM-CXCR4 null mice.

Conclusions: These data demonstrate that the local trophic effects of MSC require cardiac progenitor cell and CM-CXCR4 expression and are mediated by MSC stromal cell-derived factor-1 secretion. Our results further demonstrate and quantify for the first time a specific paracrine mechanism of MSC engraftment. In the absence of CM-CXCR4 expression, there is a significant loss of functional benefit in MSC-mediated repair despite equal increases in vascular density.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / physiology
  • Cell Movement / physiology
  • Chemokine CXCL12 / metabolism*
  • Coronary Circulation / physiology
  • Gene Expression / physiology
  • Green Fluorescent Proteins / genetics
  • Mesenchymal Stem Cell Transplantation / methods*
  • Mesenchymal Stem Cells / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myocardial Infarction / genetics
  • Myocardial Infarction / pathology
  • Myocardial Infarction / therapy*
  • Myocardium / cytology
  • Myocytes, Cardiac / cytology
  • Myocytes, Cardiac / physiology
  • Paracrine Communication / physiology
  • Receptors, CXCR4 / genetics*
  • Receptors, CXCR4 / metabolism
  • Ventricular Remodeling / physiology


  • CXCR4 protein, mouse
  • Chemokine CXCL12
  • Cxcl12 protein, mouse
  • Receptors, CXCR4
  • Green Fluorescent Proteins