Diet modification reverses diastolic dysfunction in rats with heart failure and preserved ejection fraction

Area of Science:

• Cardiology
• Renal Physiology
• Nutritional Science

Background:

• Dahl Salt-Sensitive (DSS) rats fed a high-salt diet develop heart failure with preserved ejection fraction (HFpEF).
• Hypertension-induced inflammation and ventricular fibrosis are key factors in HFpEF development.
• Dietary salt intake significantly impacts cardiovascular health and disease progression.

Purpose of the Study:

• To investigate the impact of dietary salt modification on established HFpEF in DSS rats.
• To determine if switching from a high-salt to a normal-salt diet can reverse HFpEF phenotypes.
• To assess the effects of diet modification on cardiac function, fibrosis, and survival.

Main Methods:

• Male DSS rats were fed a high-salt (8% NaCl) diet to induce HFpEF.
• Rats with confirmed diastolic dysfunction were randomized to continue high-salt or switch to a normal-salt (0.3% NaCl) diet.
• Echocardiography, treadmill exercise tests, and histological analyses (Masson's trichrome) were performed.

Main Results:

• Diet modification improved diastolic function (reduced E/E' ratio) and increased exercise capacity.
• Pulmonary congestion (lung/body weight ratio) was reduced in rats switched to a normal-salt diet.
• Ventricular fibrosis was significantly reduced, and survival was prolonged compared to rats on a continuous high-salt diet.
• Systolic blood pressure and ventricular hypertrophy remained unchanged; arrhythmia inducibility and QTc interval were not altered.

Conclusions:

• Dietary salt reduction can reverse established HFpEF phenotypes in DSS rats.
• Normal-salt diet intake mitigates cardiac fibrosis and improves functional capacity and survival.
• Diet modification offers a potential therapeutic strategy for HFpEF, independent of blood pressure control.