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Magnesium enhances function of postischaemic human myocardial tissue
S Lareau1, A Boyle, R Deslauriers
1University of Ottawa Heart Institute, Ottawa Civic Hospital, Canada.
Cardiovascular Research
|June 1, 1993
Summary
High magnesium (Mg2+) levels during rewarming of human atrial trabeculae significantly increase developed force and preserve high-energy phosphate metabolites. This finding is crucial for understanding cardiac function and preserving tissue viability in vitro.
Area of Science:
- Cardiovascular Physiology
- Biochemistry
- Cellular Metabolism
Background:
- Isolated human atrial trabeculae are used to study cardiac contractility.
- High-energy phosphate metabolites are critical for cellular energy production.
- Magnesium ions (Mg2+) play a vital role in numerous enzymatic reactions, including those involved in energy metabolism.
Purpose of the Study:
- To investigate the effect of varying Mg2+ concentrations on the developed force of isolated human atrial trabeculae.
- To determine how Mg2+ affects the concentrations of high-energy phosphate metabolites in these preparations.
Main Methods:
- Human atrial trabeculae were obtained from patients undergoing cardiac surgery.
- Trabeculae were rewarmed in modified Krebs-Henseleit buffer with either 1.2 mM or 16 mM Mg2+.
- Mechanical function was assessed, and high-energy phosphate metabolites were measured using reverse-phase high-performance liquid chromatography.
Main Results:
- Trabeculae rewarmed in 16 mM Mg2+ exhibited significantly higher developed force compared to those in 1.2 mM Mg2+.
- Total adenylate (ATP+ADP+AMP) concentrations were significantly higher in trabeculae rewarmed with 16 mM Mg2+.
- No significant differences were observed in NAD or total creatine concentrations between groups.
Conclusions:
- Elevated Mg2+ concentrations during rewarming enhance the developed force of human atrial trabeculae.
- High Mg2+ preserves a larger pool of total adenylates, indicating improved energy status.
- These findings suggest that optimizing Mg2+ levels is important for maintaining cardiac tissue function in experimental settings.