Growth hormone improves cardiac performance in experimental heart failure

Area of Science:

• Cardiology
• Endocrinology
• Pharmacology

Background:

• Growth hormone (GH) increases myocardial contractility in vitro and in humans.
• Preliminary studies suggest GH improves ventricular contractility in heart failure models.
• This study investigates GH's effects on cardiac function in a rat heart failure model.

Purpose of the Study:

• To determine the effects of growth hormone on cardiac output, stroke volume, and peripheral vascular resistance in a rat model of heart failure.
• To evaluate GH's efficacy in improving cardiac performance post-myocardial infarction.

Main Methods:

• A rat model of heart failure was created by ligating the left coronary artery.
• Rats received recombinant human growth hormone (2 mg/kg/day SC) or vehicle for 15 days.
• Cardiac output and hemodynamic parameters were measured using thermodilution and catheterization.

Main Results:

• Growth hormone treatment significantly increased cardiac index, stroke volume index, and left ventricular maximum dP/dt in ligated rats.
• GH treatment also reduced left ventricular end-diastolic pressure and systemic vascular resistance in heart failure rats.
• In sham rats, GH had minimal effects on cardiac performance.

Conclusions:

• Growth hormone treatment improves cardiac function in heart failure by enhancing myocardial contractility.
• GH also reduces peripheral vascular resistance, contributing to improved cardiac performance.
• GH shows potential as a therapeutic agent for managing heart failure.