Perturbations in myocardial perfusion and oxygen balance in swine with multiple risk factors: a novel model of ischemia and no obstructive coronary artery disease
van de Wouw, Jens; Sorop, Oana; van Drie, Ruben W A; van Duin, Richard W B; Nguyen, Isabel T N; Joles, Jaap A; Verhaar, Marianne C; Merkus, Daphne; Duncker, Dirk J
(2020) Basic Research in Cardiology, volume 115, issue 2
(Article)
Abstract
Comorbidities of ischemic heart disease, including diabetes mellitus (DM), hypercholesterolemia (HC) and chronic kidney disease (CKD), are associated with coronary microvascular dysfunction (CMD). Increasing evidence suggests that CMD may contribute to myocardial 'Ischemia and No Obstructive Coronary Artery disease' (INOCA). In the present study, we tested the hypothesis that CMD
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results in perturbations in myocardial perfusion and oxygen delivery using a novel swine model with multiple comorbidities. DM (streptozotocin), HC (high-fat diet) and CKD (renal embolization) were induced in 10 female swine (DM + HC + CKD), while 12 healthy female swine on a normal diet served as controls (Normal). After 5 months, at a time when coronary atherosclerosis was still negligible, myocardial perfusion, metabolism, and function were studied at rest and during treadmill exercise. DM + HC + CKD animals showed hyperglycemia, hypercholesterolemia, and impaired kidney function. During exercise, DM + HC + CKD swine demonstrated perturbations in myocardial blood flow and oxygen delivery, necessitating a higher myocardial oxygen extraction-achieved despite reduced capillary density-resulting in lower coronary venous oxygen levels. Moreover, myocardial efficiency was lower, requiring higher oxygen consumption for a given level of myocardial work. These perturbations in myocardial oxygen balance were associated with lower myocardial lactate consumption, stroke volume, and LVdP/dtmax, suggestive of myocardial ischemia and dysfunction. Further analyses showed a reduction in adenosine-recruitable coronary flow reserve, but this was exclusively the result of an increase in basal coronary blood flow, while maximal coronary flow per gram of myocardium was maintained; the latter was consistent with the unchanged arteriolar wall/lumen ratio, arteriolar density and peri-arteriolar collagen content. However, isolated small arteries displayed selective blunting of endothelium-dependent vasodilation in response to bradykinin in DM + HC + CKD swine, suggesting that changes in coronary microvascular function rather than in structure contributed to the perturbations in myocardial oxygen delivery. In conclusion, common comorbidities in swine result in CMD, in the absence of appreciable atherosclerosis, which is severe enough to produce perturbations in myocardial oxygen balance, particularly during exercise, resembling key features of INOCA.
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Keywords: Chronic kidney disease, Coronary microcirculation, Diabetes mellitus, Exercise, Hypercholesterolemia, INOCA, Ischemia, Swine, Cardiology and Cardiovascular Medicine, Physiology (medical), Physiology, Journal Article
ISSN: 0300-8428
Publisher: D. Steinkopff-Verlag
Note: Funding Information: The authors thank Annemarie Verzijl, Esther van de Kamp, Ilona Krabbendam, Lau Blonden, (ErasmusMC, Rotterdam, The Netherlands), Adele Dijk, Krista den Ouden, and Petra de Bree (UMC Utrecht, Utrecht, The Netherlands) for their expert technical support. Funding Information: This study was supported by grants from the European Commission FP7-Health-2010 Grant MEDIA-261409, the German Center for Cardiovascular Research (DZHK; 81Z0600207 to DM), and the Netherlands CardioVascular Research Initiative: an initiative with support of the Dutch Heart Foundation [CVON2012-08 (PHAEDRA), CVON2014-11 (RECONNECT)]. Acknowledgements Publisher Copyright: © 2020, The Author(s).
(Peer reviewed)