Fluorescence tomography of rapamycin-induced autophagy and cardioprotection in vivo.
Circ Cardiovasc Imaging
; 6(3): 441-7, 2013 May 01.
Article
in En
| MEDLINE
| ID: mdl-23537953
ABSTRACT
BACKGROUND:
Autophagy is a biological process during which cells digest organelles in their cytoplasm and recycle the constituents. The impact of autophagy in the heart, however, remains unclear in part because of the inability to noninvasively image this process in living animals. METHODS ANDRESULTS:
Here, we report the use of fluorescence molecular tomography and a cathepsin-activatable fluorochrome to image autophagy in the heart in vivo after ischemia/reperfusion and rapamycin (RAP) therapy. We show that cathepsin-B activity in the lysosome is upregulated by RAP and that this allows the expanded lysosomal compartment in autophagy to be imaged in vivo with fluorescence molecular tomography. We further demonstrate that the delivery of diagnostic nanoparticles to the lysosome by endocytosis is enhanced during autophagy. The upregulation of autophagy by RAP was associated with a 23% reduction (P<0.05) of apoptosis in the area at risk and a 45% reduction in final infarct size (19.6±5.6% of area at risk with RAP versus 35.9±9.1% of area at risk without RAP; P<0.05).CONCLUSIONS:
The ability to perform noninvasive tomographic imaging of autophagy in the heart has the potential to provide valuable insights into the pathophysiology of autophagy, particularly its role in cardiomyocyte salvage. Although additional data are needed, our study supports the investigation of RAP therapy in patients with acute coronary syndromes.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Autophagy
/
Tomography
/
Cardiovascular Agents
/
Myocardial Reperfusion Injury
/
Sirolimus
/
Optical Imaging
/
Myocardial Infarction
/
Myocardium
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Circ Cardiovasc Imaging
Journal subject:
ANGIOLOGIA
/
CARDIOLOGIA
/
DIAGNOSTICO POR IMAGEM
Year:
2013
Document type:
Article
Affiliation country:
United States