Researchers from the Spanish National Centre for Cardiovascular Research have discovered that a fatty acid found in mother’s milk helps mouse pups’ hearts to mature. The fatty acid, called ɣ-linolenic acid (GLA), is essential for pups to obtain through their mother’s milk. In the womb, the cells of the heart gobble up glucose to produce energy. After birth, a “switching” occurs, which sees cardiomyocytes burning lipids instead for the rest of the mammal’s lifetime. GLA helps to reshape the cardiomyocytes’ fuel preference. The study could lead to new treatments for cardiovascular diseases in humans.
As per the analysis by a recent study published in Nature, researchers from the Spanish National Centre for Cardiovascular Research (NCIC) have discovered that a fatty acid found in mother’s milk helps mouse pups’ hearts to mature. The study sheds light on the cellular mechanisms responsible for reshaping the cardiomyocytes’ fuel preferences, which were previously unknown.
Baby mammals’ hearts must produce sufficient energy to enable contraction of the heart muscle, which is a big metabolic task. In the womb, the cells of the heart, known as cardiomyocytes, gobble up glucose to produce this energy. After birth, a “switching” occurs, which sees cardiomyocytes burning lipids instead for the rest of the mammal’s lifetime.
“The need to maintain a constant and uninterrupted beat places an immense energy demand on the heart,” explains Dr. Mercedes Ricote, a biologist at NCIC. To meet their energy needs, cardiomyocytes maintain a tight control over the cellular pathways that produce energy. Any imbalance in these bioenergetic mechanisms can lead to the development of serious cardiovascular pathologies.
The challenge for scientists such as Ricote, who studies nuclear receptor signaling, was that the cellular mechanisms responsible for reshaping the cardiomyocytes’ fuel preferences were unknown. Alongside her colleagues at NCIC, she embarked on a seven-year-long quest to find answers.
The research team fed pups milk from mothers eating standard mouse chow and a second cohort fed fat-free chow. The pups eating the fat-free chow developed cardiac issues and, in many cases, died. This experiment pointed towards the mother’s diet – and therefore the components of their milk – as a potential area of interest for mouse pup heart development.
Analyzing the molecular constituents of the milk, Ricote and colleagues identified one essential fatty acid – called ɣ-linolenic acid or GLA – which pups can only obtain through their mother’s milk. The team found that GLA activates a nuclear receptor called PPARα, which in turn activates a genetic program that allows cardiomyocytes to burn fat instead of glucose.
The researchers found that the pups’ hearts that were fed GLA-rich milk had a more mature heart muscle, which was better able to withstand metabolic stress. The study also revealed that GLA-rich milk could protect the heart from damage caused by low oxygen levels, a condition known as hypoxia.
The discovery of GLA’s role in the development of cardiomyocytes’ fuel preferences could have implications for the treatment of cardiovascular diseases in humans. “Our results suggest that the nutritional composition of mother’s milk could be harnessed to protect newborns from cardiovascular diseases later in life,” Ricote says.
In retrospect, the study provides valuable insights into the cellular mechanisms responsible for reshaping the cardiomyocytes’ fuel preferences, which were previously unknown. The discovery of GLA’s role in the development of cardiomyocytes’ fuel preferences could have implications for the treatment of cardiovascular diseases in humans. It highlights the importance of a mother’s diet and the nutritional composition of mother’s milk in the development of a mouse pup’s heart.
