Abstract 17689: Imaging Mitochondrial Function of Mesenchymal Stem Cells Transplanted to the Myocardium
Introduction: Stem cells have poor survival after transplantation, what can limit the use of these therapies. Mitochondrial dysfunction has been recognized as a limiting event that can lead to cell death. Here, we hypothesized that the mitochondrial function of progenitor cells can be monitored in vivo using reporter gene-based molecular imaging. A better understanding of the biology of transplanted stem cells in the ischemic myocardium can lead to optimization of cell therapies.
Methods: Using RT-PCR we identified the antioxidant NAD(P)H:Quinone oxidoreductase (NQO1) enzyme as a marker of mitochondrial dysfunction in mouse Mesenchymal Stem Cells (MSCs) that were treated with a mitochondrial stressor, diethyl maleate (DEM). We then constructed a luciferase reporter gene driven by the NQO1 promoter. After in vitro validation, MSCs were transplanted into a mouse model of ischemia/reperfusion (IR, n=4) and mitochondrial function was monitored by bioluminescence imaging.
Results: MSCs treated with DEM had an increase in NQO1 reporter gene signal that inversely correlated with the amount of the mitochondrial by-product adenosine tri-phosphate (ATP, r = -0.9643, p = 0.0028; Fig 1A). Mitochondrial dysfunction was preserved by the use of a mitochondria-targeted antioxidant Mito-Tempo (MT), correcting ATP and NQO1 luciferase signal. In vivo studies showed that MSCs yielded higher Firefly luciferase activity in IR mice compared to sham and this signal was normalized when cells were pre-treated with MT (Fig 1B). Data was confirmed by ex vivo measurement of Firefly luciferase activity, which was 4.9-fold higher in the IR group than in shams, after correction for cell number (Fig 1C).
Conclusions: We have developed a novel imaging strategy that allows noninvasive assessment of the mitochondrial status of transplanted stem cells in the ischemic myocardium. Knowing when transplanted cells “suffer’ from mitochondrial dysfunction may allow optimization of these therapies.
Author Disclosures: F. Franchi: None. K.M. Peterson: None. R. Paulmurugan: None. A. Lerman: None. M.G. Rodriguez-Porcel: None.
This research has received full or partial funding support from the American Heart Association.
- © 2014 by American Heart Association, Inc.