Magnetic resonance imaging of cardiomyocyte apoptosis with a novel magneto-optical nanoparticle.
The ability to image cardiomyocyte apoptosis in vivo with high-resolution MRI could facilitate the development of novel cardioprotective therapies. The sensitivity of the novel nanoparticle AnxCLIO-Cy5.5 for cardiomyocyte apoptosis was thus compared in vitro to that of annexin V-FITC and showed a high degree of colocalization. MRI was then performed, following transient coronary artery (LAD) occlusion, in five mice given AnxCLIO-Cy5.5 and in four mice given an identical dose (2 mg Fe/kg) of CLIO-Cy5.5. MR signal intensity and myocardial T2* were evaluated, in vivo, in hypokinetic regions of myocardium in the LAD distribution. Ex vivo fluorescence imaging was performed to confirm the in vivo findings. Myocardial T2* was significantly lower in the mice given AnxCLIO-Cy5.5 (8.1 versus 13.2 ms, P<0.01), and fluorescence target to background ratio was significantly higher (2.1 versus 1.1, P<0.01). This study thus demonstrates the feasibility of obtaining high-resolution MR images of cardiomyocyte apoptosis in vivo with the novel nanoparticle, AnxCLIO-Cy5.5.
Sosnovik
David E
DE
Center for Molecular Imaging Research, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA. Sosnovik@nmr.mgh.harvard.edu
Schellenberger
Eyk A
EA
Nahrendorf
Matthias
M
Novikov
Mikhail S
MS
Matsui
Takashi
T
Dai
George
G
Reynolds
Fred
F
Grazette
Luanda
L
Rosenzweig
Anthony
A
Weissleder
Ralph
R
Josephson
Lee
L
D000704:Analysis of Variance; D000818:Animals; D017304:Annexin A5 / Q000493:pharmacokinetics*; D017209:Apoptosis; D003287:Contrast Media / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D032383:Myocytes, Cardiac; D036103:Nanotechnology
D017304:Annexin A5; D003287:Contrast Media