Longitudinal micro-ultrasound assessment of the ob/ob mouse model: evaluation of cardiovascular, renal and hepatic parameters

BACKGROUND/OBJECTIVES: Obesity is reaching epidemic proportions and is associated with increased risk factors for cardiovascular disease. Leptin-deficient mice (ob/ob) are widely employed to investigate obesity. Aim of this study was to provide a micro-ultrasound (mu US) longitudinal evaluation of the ob/ob mouse model in terms of cardiovascular effects, consequences for renal microcirculation and liver fat accumulation. SUBJECTS/METHODS: Sixteen wild-type (wt) and eleven ob/ob male mice were studied at 8 (T-0) and 25 (T-1) weeks of age with a mu US system (Vevo2100) and B-mode and Doppler images were acquired. Cardiac output (CO), ejection fraction (EF), stroke volume (SV), fractional shortening (FS) and E/A ratio were measured from cardiac images. Mean diameter (Dm(abd), Dm(car)), relative distension (relD(abd) and relD(car)) and pulse wave velocity (PWVabd and PWVcar) were obtained for both abdominal aorta and common carotid. As regards renal microcirculation, renal resistivity and pulsatility index (RI and PI) were assessed. The ratio between grey levels related to liver and kidney (Steato-Score) was used as index of hepatic steatosis.