In vivo cardiac 31P MRS in a mouse model of heart failure

Abstract

ObjectiveTo investigate myocardial energy status in a mouse model of heart failure using in vivo 31P magnetic resonance spectroscopy (MRS).MethodsMale C57BL/6 mice underwent thoracic aortic constriction (TAC) surgery, inducing pressure‐overload cardiomyopathy, and were measured seven weeks after surgery (n = 5). Healthy wild‐type mice served as controls (n = 4). Cardiac cine 1H MR images were made for reference purposes and to quantify left ventricular (LV) function. Cardiac 31P MR spectra were measured from a ~6 mm cubic voxel enclosing the end‐diastolic LV myocardium using ECG triggered, respiratory gated 3D Image‐Selected In vivo Spectroscopy (ISIS).ResultsLV end‐diastolic volume and LV mass normalized to body weight were higher in TAC mice compared to controls (91.7 ± 19.0 versus 61.8 ± 6.0 μL and 4.4 ± 0.6 versus 3.1 ± 0.2 mg/g, P < 0.01), whereas LV ejection fraction was reduced in TAC mice (45.4 ± 20.0 versus 64.4 ± 5.2 %, P < 0.05). Myocardial phosphocreatine‐to‐ATP ratio was lower in TAC mice when compared to healthy controls (0.8±0.2 versus 1.2±0.2, P < 0.05).ConclusionDecreased EF in TAC mice is accompanied by decreased phosphocreatine‐to‐ATP ratio, indicating a disturbed energy homeostasis in this mouse model of heart failure. This research was funded by a VIDI grant from the Netherlands Organisation for Scientific Research (NWO).