Assessment of the early stage of cardiac remodeling of spontaneously hypertensive heart failure rats using the quantitative 3-dimensional analysis provided by acipimox-enhanced FDG-PET.

Spontaneously hypertensive heart failure rats (SHHF) appear to constitute an original model for analyzing the evolution of the metabolic syndrome towards heart failure. This study aimed to characterize early cardiac dysfunction and remodeling in SHHF rats: (1) as compared with spontaneously hypertensive rats (SHR) and with a control group of Kyoto rats (WKY), and (2) by using the 3-dimensional quantitative analysis provided by acipimox-enhanced positron emission tomography (PET) with (18)F-fluorodesoxyglucose (FDG). Left ventricular (LV) ejection fraction (EF) and volume were quantified by automatic software on the FDG-PET images recorded in SHR (n = 20), SHHF (n = 18) and WKY-rats (n = 19) at ages 3 or 10 months old. Arterial blood pressure was determined by cardiac catheterization and cardiac fibrosis was quantified after sacrifice. Blood pressure was similarly elevated in SHR and SHHF rats (respective systolic blood pressures at 10-months: 199 ± 39 vs. 205 ± 2 mmHg), but SHHF rats had higher body mass than SHR rats (at 10-months, 630 ± 36 vs. 413 ± 27 g, p < 0.05) and higher blood levels of cholesterol and of triglycerides. At 3 months, cardiac parameters did not show significant differences between groups but at 10-months, SHHF and SHR rats exhibited an enhancement in myocardial mass and fibrosis associated with a clear decline in LV-EF (SHHF: 46 ± 6 %; SHR: 47 ± 5 %) as compared with WKY (56 ± 6 %, p < 0.01 for both comparisons). Cardiac remodeling of SHHF rats was clearly observable by FDG-PET from the age of 10-months, but in a similar way to that observed for SHR rats, suggesting a predominant role of hypertension.