Apolipoprotein A-IMilano/POPC complex attenuates post-ischemic ventricular dysfunction in the isolated rabbit heart

Area of Science:

• Cardiovascular Science
• Biochemistry
• Pharmacology

Background:

• Myocardial injury can occur after coronary artery revascularization due to reperfusion-induced oxidative damage.
• High-density lipoproteins (HDL) possess antioxidant properties, effectively removing oxidized lipids.
• Recombinant apolipoprotein A-I(Milano) (apoA-I(M)) complexed with phospholipids represents a potential therapeutic HDL mimetic.

Purpose of the Study:

• To investigate the cardioprotective effects of a synthetic HDL preparation, apoA-I(M)/POPC, against myocardial reperfusion injury.
• To evaluate the impact of apoA-I(M)/POPC on cardiac function, oxidative stress markers, and ultrastructural changes during ischemia-reperfusion.

Main Methods:

• An ex vivo rabbit heart model using the Langendorff perfusion system was employed.
• Hearts were pretreated with apoA-I(M)/POPC or vehicle, subjected to global ischemia, and then reperfused.
• Measurements included left ventricular end-diastolic pressure, coronary artery perfusion pressure, creatine kinase release, lipid hydroperoxides, and electron microscopy.

Main Results:

• ApoA-I(M)/POPC significantly prevented left ventricular end-diastolic pressure elevation and maintained coronary artery perfusion pressure during reperfusion.
• The synthetic HDL reduced creatine kinase release and cardiac left ventricle muscle lipid hydroperoxides by 46%.
• Electron microscopy confirmed that apoA-I(M)/POPC prevented mitochondrial damage and sarcomere alterations characteristic of reperfusion injury.

Conclusions:

• The synthetic HDL complex, apoA-I(M)/POPC, effectively reduces myocardial reperfusion injury in an ex vivo setting.
• Its potent antioxidant capacity and ability to preserve cardiac structure suggest therapeutic potential for reducing ischemia-related heart damage.