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Chang H, Tran T, Billman GE, Julian MW, Hamlin RL, Simonetti OP, Ambrosio G, Baker PB, Shao G, Crouser ED, Raman SV. At-risk but viable myocardium in a large animal model of non ST-segment elevation acute coronary syndrome: cardiovascular magnetic resonance with ex vivo validation. J Cardiovasc Magn Reson 2013; 15:94. [PMID: 24107555 PMCID: PMC3852225 DOI: 10.1186/1532-429x-15-94] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 10/01/2013] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) have varying degrees of salvageable myocardium at risk of irreversible injury. We hypothesized that a novel model of NSTE-ACS produces acute myocardial injury, measured by increased T2 cardiovascular magnetic resonance (CMR), without significant necrosis by late gadolinium enhancement (LGE). METHODS In a canine model, partial coronary stenosis was created and electrodes placed on the epicardium. Myocardial T2, an indicator of at-risk myocardium, was measured pre- and post-tachycardic pacing. RESULTS Serum troponin-I (TnI) was not detectable in unoperated sham animals but averaged 1.97 ± 0.72 ng/mL in model animals. Coronary stenosis and pacing produced significantly higher T2 in the affected vs. the remote myocardium (53.2 ± 4.9 vs. 43.6 ± 2.8 ms, p < 0.01) with no evident injury by LGE. Microscopy revealed no significant irreversible cellular injury. Relative respiration rate (RRR) of affected vs. remote myocardial tissue was significantly lower in model vs. sham animals (0.72 ± 0.07 vs. 1.04 ± 0.07, p < 0.001). Lower RRR corresponded to higher final TnI levels (R(2) = 0.83, p = 0.004) and changes in CaMKIID and mitochondrial gene expression. CONCLUSIONS A large animal NSTE-ACS model with mild TnI elevation and without ST elevation, similar to the human syndrome, demonstrates signs of acute myocardial injury by T2-CMR without significant irreversible damage. Reduced tissue respiration and associated adaptations of critical metabolic pathways correspond to increased myocardial injury by serum biomarkers in this model. T2-CMR as a biomarker of at-risk but salvageable myocardium warrants further consideration in preclinical and clinical studies of NSTE-ACS.
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Affiliation(s)
- Henry Chang
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
| | - Tam Tran
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
| | - George E Billman
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
- Department of Physiology and Cell Biology, OSU, 370 W 9th Ave, Columbus, OH 43210, USA
| | - Mark W Julian
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
| | - Robert L Hamlin
- Department of Veterinary Biosciences, OSU, 1900 Coffey Road, Columbus, OH 43210, USA
| | - Orlando P Simonetti
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
- Division of Cardiovascular Medicine, OSU, 473 W 12th Ave, Columbus, OH 43210, USA
- Department of Radiology, OSU, 395 W 12th Ave, Columbus, OH 43210, USA
| | - Giuseppe Ambrosio
- Division of Cardiology, University of Perugia, Ospedale S. Maria della Misericordia, Via S. Andrea delle fratte, 06156 Perugia, Italy
| | - Peter B Baker
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
- Department of Pathology, OSU and Nationwide Children’s Hospital, 700 Children’s Dr, Columbus, OH 43205, USA
| | - Guohong Shao
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
| | - Elliott D Crouser
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, OSU, 473 W 12th Ave, Columbus, OH 43210, USA
| | - Subha V Raman
- Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, 473 W 12th Ave, Suite 200, Columbus, OH 43210, USA
- Division of Cardiovascular Medicine, OSU, 473 W 12th Ave, Columbus, OH 43210, USA
- Department of Radiology, OSU, 395 W 12th Ave, Columbus, OH 43210, USA
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