title: Obesity alters molecular and functional cardiac responses to ischemia/reperfusion and glucagon-like peptide-1 receptor agonism.
abstract: This study tested the hypothesis that obesity alters the cardiac response to ischemia/reperfusion and/or glucagon like peptide-1 (GLP-1) receptor activation, and that these differences are associated with alterations in the obese cardiac proteome and microRNA (miRNA) transcriptome. Ossabaw swine were fed normal chow or obesogenic diet for 6 months. Cardiac function was assessed at baseline, during a 30-minutes coronary occlusion, and during 2 hours of reperfusion in anesthetized swine treated with saline or exendin-4 for 24 hours. Cardiac biopsies were obtained from normal and ischemia/reperfusion territories. Fat-fed animals were heavier, and exhibited hyperinsulinemia, hyperglycemia, and hypertriglyceridemia. Plasma troponin-I concentration (index of myocardial injury) was increased following ischemia/reperfusion and decreased by exendin-4 treatment in both groups. Ischemia/reperfusion produced reductions in systolic pressure and stroke volume in lean swine. These indices were higher in obese hearts at baseline and relatively maintained throughout ischemia/reperfusion. Exendin-4 administration increased systolic pressure in lean swine but did not affect the blood pressure in obese swine. End-diastolic volume was reduced by exendin-4 following ischemia/reperfusion in obese swine. These divergent physiologic responses were associated with obesity-related differences in proteins related to myocardial structure/function (e.g. titin) and calcium handling (e.g. SERCA2a, histidine-rich Ca(2+) binding protein). Alterations in expression of cardiac miRs in obese hearts included miR-15, miR-27, miR-130, miR-181, and let-7. Taken together, these observations validate this discovery approach and reveal novel associations that suggest previously undiscovered mechanisms contributing to the effects of obesity on the heart and contributing to the actions of GLP-1 following ischemia/reperfusion.
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Sassoon
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Adam G
authors.initials: AG
authors.lastname: Goodwill
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Jillian N
authors.initials: JN
authors.lastname: Noblet
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Abass M
authors.initials: AM
authors.lastname: Conteh
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: B Paul
authors.initials: BP
authors.lastname: Herring
authors.affiliation: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Jeanette N
authors.initials: JN
authors.lastname: McClintick
authors.affiliation: Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, USA.
authors.forename: Johnathan D
authors.initials: JD
authors.lastname: Tune
authors.affiliation: Department of Medicine, Indiana University School of Medicine, 1120 W. Michigan St., Suite CL365, Indianapolis, IN, 46202, USA. kmather@iu.edu.
authors.forename: Kieren J
authors.initials: KJ
authors.lastname: Mather
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism*; D000067757:Glucagon-Like Peptide-1 Receptor / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D040901:Proteomics; D013552:Swine; D059467:Transcriptome
chemical_list: D000067757:Glucagon-Like Peptide-1 Receptor; D052216:Glucagon-Like Peptide 1
keywords: Cardiovascular; Exendin-4; GLP-1; Ischemia; MicroRNA; Obesity; Proteomics