How the heart's unusual carbohydrate metabolism helps it stay strong
The heart is the hardest-working muscle in the body, beating constantly no matter what the body's energy reserves look like. Maintaining energy flow to the heart is a complex process that can break down during common but severe cardiovascular disease conditions like heart failure. Researchers previously knew that heart muscle seems to do an unusual metabolic trick to always get enough energy:…
The heart is an exceptionally hardworking muscle, constantly beating regardless of the body's energy reserves. In cases of common but severe cardiovascular diseases, such as heart failure, the energy flow to the heart can be compromised. Previous research had discovered that heart muscle employs an unusual metabolic strategy to consistently secure enough energy: utilizing both glucose and lactate simultaneously.
However, unlike most human tissues where the use of more glucose hinders lactate utilization, and vice versa, the heart demonstrates a unique capability. Researchers have now identified a critical cellular distinction that aids in sustaining heart muscle fueling: the ability to burn glucose within the cytosol (the cell's main body) while simultaneously burning lactate in the mitochondria (the cell's powerhouse).
This spatial separation enables both energy-generating reactions to occur concurrently, ensuring the heart remains fueled regardless of the energy source. This intricate process, while largely inconsequential to daily life, is essential for averting heart failure when the heart is under stress. Professor Gregory Ducker from the University of Utah Health, the senior author of the study, emphasizes its criticality, stating, "In an emergency, we would really, really rely on this."
The researchers have found that the separation between glucose and lactate metabolism hinges on a molecule called MCT1, which facilitates lactate entry into the mitochondria. Genetic mutations in MCT1 disrupt the heart's energy balance, leading to heart failure under stress. These findings reveal a new necessity for lactate to fuel the damaged heart and suggest novel therapeutic targets to re-energize the heart during heart failure.
Ducker concludes, "This discovery opens promising opportunities for developing new treatments for serious heart conditions, including heart failure and heart attacks, by harnessing the heart's ability to use lactate as a valuable energy source."
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