Abstract P364: Liraglutide Protects Against Angiotensin-induced Diastolic Dysfunction And Is Associated With Altered Acetyl-coa Metabolism

Abstract

Background: The mechanisms underlying diastolic dysfunction remain complicated and poorly understood. Previously implicated mechanisms include increased interstitial fibrosis and oxidative damage, altered calcium handling, and mitochondrial dysfunction. In this study, we investigate changes in the cardiac metabolic profile from mice with Angiotensin-II (Ang)-induced diastolic dysfunction. Because treatment with the GLP-1 agonist liraglutide (Lira) relieves Ang-induced diastolic dysfunction, we examined altered metabolites in Ang and Ang+Lira mice to identify metabolic pathways involved. Methods: 8-wk mice were implanted with Ang pumps (1000 ng/kg/min) +/- Lira (0.2 mg/kg/day) therapy for 4 wks and compared to sham mice. Baseline and 4-wk echocardiography was performed. Hearts were collected for RNA-sequencing, Western blot, histology, radiolabeled palmitate assay, and targeted metabolomics by liquid chromatography-mass spectrometry to assess metabolic changes. Results: After Ang treatment, mice had significant diastolic dysfunction but only mild hypertrophy based on echo and histologic measures and no evidence of systolic change. Compared to sham mice, Ang mice had reduced E/A (Sham, 2.67±0.40; Ang, 1.71±0.11; p<0.05) and peak reverse longitudinal strain rate (rLSR;Sham, 8.48±0.65/s; Ang, 6.081±0.33/s; p<0.05, consistent with diastolic dysfunction. Ang+Lira mice had improved E/A (3.57±0.50, p<0.01 vs. Ang) and rLSR (8.65±0.68/s, p<0.01 vs Ang). Targeted metabolomic analysis of hearts found significantly increased accumulation of Acetyl-CoA in Ang mice (peak area 0.14±0.02) compared to sham (0.04±0.02 ,p<0.05) that is restored by Lira therapy (0.02±0.01 ,p<0.05 vs sham and Ang). A radiolabeled palmitate oxidation assay found decreased palmitate oxidation in both Ang and Ang+Lira mice compared to sham, but interestingly, also demonstrated significantly lower acid soluble metabolite oxidation in the Ang+Lira mice vs. Ang alone. Conclusions: We found that Ang-treated mice accumulate myocardial Acetyl-CoA, suggesting a defect in TCA flux. Lira resolves the increase in Acetyl-CoA and improved measures of diastolic dysfunction. This data may implicate a novel metabolic pathway in the development of diastolic disease.