BACKGROUND: Despite recent advances, myocardial infarction (MI) remains the leading cause of death worldwide. Pre-clinical animal models that closely mimic human MI are pivotal for a quick translation of research and swine have similarities in anatomy and physiology. Here, we compared coronary surgical ligation versus coil embolization MI models in swine.
METHODS: Fifteen animals were randomly distributed to undergo surgical ligation (n=7) or coil embolization (n=8). We evaluated infarct size, scar fibrosis, inflammation, myocardial vascularization, and cardiac function by magnetic resonance imaging (MRI).
RESULTS: Thirty-five days after MI, there were no differences between the models in infarct size (P=0.53), left ventricular (LV) ejection fraction (P=0.19), LV end systolic volume (P=0.22), LV end diastolic volume (P=0.84), and cardiac output (P=0.89). Histologically, cardiac scars did not differ and the collagen content, collagen type I (I), collagen type III (III), and the I/III ratio were similar in both groups. Inflammation was assessed using specific anti-CD3 and anti-CD25 antibodies. There was similar activation of inflammation throughout the heart after coil embolization (P=0.78); while, there were more activated lymphocytes in the infarcted myocardium in the surgical occlusion model (P=0.02). Less myocardial vascularization in the infarction areas compared with the border and remote zones only in coil embolization animals was observed (P=0.004 and P=0.014, respectively).
CONCLUSIONS: Our results support that surgical occlusion and coil embolization MI models generate similar infarct size, cardiac function impairment, and myocardial fibrosis; although, inflammation and myocardial vascularization levels were closer to those found in humans when coil embolization was performed.