Comprehensive phenotyping of salt-induced hypertensive heart disease in living mice using cardiac magnetic resonance

Objectives

To characterise the effects of high-salt diet (HSD) on left ventricular (LV) mass, systolic function and coronary reserve in living mice using cardiac magnetic resonance imaging (MRI).

Methods

Thirty C57BL/6 1-month-old female mice were fed either a control (n?=?15) or an HSD (n?=?15). After 3 months, LV volumes, ejection fraction and mass were assessed using time-resolved three-dimensional (3D) black-blood manganese-enhanced MRI, and coronary flow velocity reserve (CFVR) was assessed using dynamic MR angiography at rest and during adenosine-induced hyperaemia. Hearts were excised to assess LV wet mass and micro-vascular remodelling at histology.

Results

Micro-vascular remodelling was found at histology in all investigated hearts from the HSD group and none from the control group. No difference between the HSD and control groups was found in terms of heart weight, LV volumes and ejection fraction. Heart to body weight ratio was higher in the HSD group (4.39?±?0.24 vs 4.02?±?0.16 mg/g, P?P?P?Conclusions Phenotyping of hypertensive heart disease is feasible in living mice using dynamic MR angiography and time-resolved 3D black-blood manganese-enhanced MRI. HSD is associated with early impairment of coronary reserve, before the onset of significant hypertrophy.

Key Points

? In vivo phenotyping of hypertensive heart disease is feasible in mice using MRI ? HSD in mice is associated with early impairment of coronary reserve ? Dietary salt in mice alters coronary reserve before the onset of ventricular hypertrophy