Scientists from Spain’s National Center for Cardiovascular Research discovered that gamma-linolenic acid in the breast milk of mice keeps the puppies’ hearts functioning properly after birth. The results of the study, which could form the basis for the treatment of mitochondrial diseases, were published in the journal. Nature.
After birth, a newborn mammal’s heart must rapidly generate energy to keep the heart beating outside the womb. To do this, contracting heart cells must activate their mitochondria, the organelles responsible for producing energy in cells. Although this process is critical to the survival of the organism, little was known until now about the signals that trigger the physiological adaptation of the heart after birth.
Experiments by scientists have shown that gamma-linolenic acid found in breast milk binds to the RXR protein found in heart cells. This leads to the activation of genes responsible for supplying the mitochondria (the energy centers of cells) with the proteins they need to consume fat, the main energy source in a mature heart.
In experiments on mice, biologists have found that the absence of the RXR protein in the heart or the absence of gamma-linolenic acid in human milk prevents the mitochondria in the heart of newborn mice from producing proper energy, leading to severe heart failure and death. Up to 48 hours after birth.
“Birth is a physiological challenge for a newborn baby. In this study, we show that in addition to the nutritional function of breast milk, it plays a signaling role to signal to cardiomyocytes that they must activate their metabolism as maternal physiology no longer supports them.”
The results pave the way for the treatment of mitochondrial diseases by controlling the activity of the RXR protein in cardiomyocytes with certain drugs, including those present.