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Lipid emulsion enhances cardiac performance after ischemia-reperfusion in isolated hearts from summer-active arctic ground squirrels. J Comp Physiol B 2017 Jul;187(5-6):715-724

Date

04/02/2017

Pubmed ID

28364393

Pubmed Central ID

PMC6145465

DOI

10.1007/s00360-017-1071-z

Abstract

Hibernating mammals, like the arctic ground squirrel (AGS), exhibit robust resistance to myocardial ischemia/reperfusion (IR) injury. Regulated preference for lipid over glucose to fuel metabolism may play an important role. We tested whether providing lipid in an emulsion protects hearts from summer-active AGS better than hearts from Brown Norway (BN) rats against normothermic IR injury. Langendorff-prepared AGS and BN rat hearts were perfused with Krebs solution containing 7.5 mM glucose with or without 1% Intralipid™. After stabilization and cardioplegia, hearts underwent 45-min global ischemia and 60-min reperfusion. Coronary flow, isovolumetric left ventricular pressure, and mitochondrial redox state were measured continuously; infarct size was measured at the end of the experiment. Glucose-only AGS hearts functioned significantly better on reperfusion than BN rat hearts. Intralipid™ administration resulted in additional functional improvement in AGS compared to glucose-only and BN rat hearts. Infarct size was not different among groups. Even under non-hibernating conditions, AGS hearts performed better after IR than the best-protected rat strain. This, however, appears to strongly depend on metabolic fuel: Intralipid™ led to a significant improvement in return of function in AGS, but not in BN rat hearts, suggesting that year-round endogenous mechanisms are involved in myocardial lipid utilization that contributes to improved cardiac performance, independent of the metabolic rate decrease during hibernation. Comparative lipid analysis revealed four candidates as possible cardioprotective lipid groups. The improved function in Intralipid™-perfused AGS hearts also challenges the current paradigm that increased glucose and decreased lipid metabolism are favorable during myocardial IR.

Author List

Salzman MM, Cheng Q, Deklotz RJ, Dulai GK, Douglas HF, Dikalova AE, Weihrauch D, Barnes BM, Riess ML

Author

Dorothee Weihrauch DVM, PhD Professor in the Anesthesiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Animals
Emulsions
Female
Glucose
Heart
Male
Myocardial Reperfusion Injury
Phospholipids
Rats
Sciuridae
Seasons
Soybean Oil
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