glucagon-like peptide-1 receptor expression after myocardial infarction: imaging study using 68 ga-nodaga-exendin-4 positron emission tomography

Activation of glucagon-like peptide-1 receptor (glp-1r) signaling protects against cardiac dysfunction and remodeling after myocardial infarction (mi). the aim of the study was to evaluate 68ga-nodaga-exendin-4 positron emission tomography (pet) for assessment of glp-1r expression after mi in rats. rats were studied at 3 days, 1 and 12 weeks after permanent coronary ligation or a sham-operation. rats were injected with 68ga-nodaga-exendin-4 and scanned with pet and contrast-enhanced computed tomography (ct) followed by digital autoradiography and histology of left ventricle tissue sections. 68ga-nodaga-exendin-4 pet/ct showed focally increased tracer uptake in the infarcted regions peaking at 3 days and continuing at 1 week after mi. pre-treatment with an unlabeled exendin-4 peptide significantly reduced 68ga-nodaga-exendin-4 uptake. by autoradiography, 68ga-nodaga-exendin-4 uptake was 8.6-fold higher in the infarcted region and slightly increased also in the remote, non-infarcted myocardium at 1 week and 12 weeks post-mi compared with sham. uptake of 68ga-nodaga-exendin-4 correlated with the amount of cd68-positive macrophages in the infarcted area and alpha-smooth muscle actin staining in the remote myocardium. 68ga-nodaga-exendin-4 pet detects up-regulation of cardiac glp-1r expression during healing of mi in rats and provide information on the activated repair mechanisms after ischemic myocardial injury.