Abstract 15814: Imaging Local and Systemic Reactive Oxygen Species After Ischemia-reperfusion Injury in Swine With Multimodal 18 F-ROStrace PET/CT and CMR
Sophia Swago, Elizabeth W Thompson, Abhijit Bhattaru, Brianna F Moon, Giovanni Ferrari, Estibaliz Castillero, Evan Gallagher, Meagan Mcmanus, Victor A Ferrari, Robert Gorman, Cory Tschabrunn, Robert H Mach, Joel S Karp, Walter R Witschey, Paco E Bravo- Physiology (medical)
- Cardiology and Cardiovascular Medicine
Introduction Reperfusion injury after myocardial infarction (MI) can cause additional tissue damage and is associated with adverse outcomes, and inflammation of extra-cardiac tissue may occur post-MI. In this study, we used positron emission tomography (PET) radiotracer [18F]ROStrace to image reactive oxygen species (ROS) in myocardium and in extra-cardiac tissues in a swine model of subacute ischemia-reperfusion injury.
Methods The mid left anterior descending coronary artery was occluded in three swine for 90 minutes, followed by reperfusion. Baseline and post-MI ROStrace data were acquired 3 days post-MI on the long axial field-of-view PennPET Explorer PET/CT system. A [82]Rb scan was acquired to calculate myocardial blood flow (MBF). Regions of interest (ROIs) were drawn in brain, lungs, bone marrow, spleen, skeletal muscle, myocardium (baseline) and infarcted and non-infarct myocardium (post-MI). ROStrace fractional uptake rate (FUR) was calculated in all ROIs. Cardiac FUR was corrected for MBF. Paired T-tests and Cohen's d effect size (ES) were used to evaluate the effect of MI on ROStrace activity in cardiac and extra-cardiac tissues. Cardiac MRI was done to quantify infarct size.
Results In extra-cardiac tissues, MI had a nonsignificant medium effect on ROS in bone marrow (ES = 0.54, p = 0.45) and spleen (ES = 0.60, p=0.41), and a nonsignificant large effect in skeletal muscle (ES = 1.24, p = 0.17). No effect was seen in brain and lungs. In the heart, MI had a significant large effect on ROS in the region of the infarct, compared to baseline (ES = 3.84, p = 0.02) (Fig. 1). Infarct size on late gadolinium enhanced MRI ranged from 16.73 to 33.62% of the myocardium.
Conclusion For the first time, systemic and local effects on ROS after MI were directly imaged using whole-body [18F]ROStrace PET. We found that ROS are increased in the infarcted myocardium in the subacute phase, and MI leads to moderate-to-large effects in ROS levels in hematopoietic tissues and skeletal muscle.