Cardiac function and glycogen content after twenty-four-hour preservation with various metabolic substrates

Area of Science:

• Cardiology
• Organ Preservation
• Biochemistry

Background:

• Cardiac function recovery after prolonged preservation may improve with exogenous substrates.
• Previous studies are difficult to interpret due to varied preservation protocols and models.
• This study evaluates glucose, pyruvate, aspartate, and glutamate for heart perfusion preservation.

Purpose of the Study:

• To assess the efficacy of different exogenous substrates in improving cardiac function after prolonged heart preservation.
• To compare the effects of aspartate, glutamate, pyruvate, and glucose on post-preservation heart recovery.

Main Methods:

• Rat hearts were preserved for 24 hours using a crystalloid medium with glucose and one of four substrates: aspartate, glutamate, pyruvate, or no additional substrate.
• Post-preservation cardiac function was evaluated using an isolated working heart model with a 4-hour reperfusion period.
• Tissue glycogen content and substrate consumption were measured.

Main Results:

• Hearts preserved with aspartate or glutamate plus glucose showed 50-60% of control stroke work and full recovery.
• Hearts preserved with glucose alone had inconsistent recovery, with some failing to recover.
• Pyruvate-preserved hearts did not recover contractile function; no correlation was found between glycogen content and recovery.

Conclusions:

• Aspartate or glutamate combined with glucose represents the optimal substrate mixture for long-term heart perfusion preservation among those tested.
• These amino acids offer superior chemical stability and better cardiac recovery compared to pyruvate.
• Aspartate/glutamate plus glucose yielded superior post-preservation function compared to glucose alone.