Watch: What can a little fish tell us about repairing our hearts?

BHF researchers are investigating how fish living in northern Mexico could help us mend damaged hearts. Watch our animation to find out how research into understanding these amazing fish could help patients following a heart attack.


Unlike other types of muscle, our heart does not have the natural ability to repair itself. When someone has a heart attack, heart muscle becomes damaged and scar tissue forms. This scar tissue stops the heart from contracting properly, making it harder for the heart to pump blood around the body. This loss of pumping ability is called heart failure.

Current BHF research led by Dr Mathilda Mommersteeg at the University of Oxford is investigating how a species of Mexican cavefish (Astyanax mexicanus) could help us to find new ways to regenerate human heart tissue to help repair heart muscle after a heart attack. 

At least 1.5 million years ago, these fish living in the rivers of northern Mexico were split into different populations as a result of flooding. Some of the fish were washed out of the rivers and into caves. The river fish have the ability to repair their hearts if they get damaged.

The fact that these two populations of fish have evolved differently gives BHF researchers a unique opportunity.

The fish living in the darkness of the Pachon caves evolved differently. They lost their pigmentation, became blind and – importantly for Dr Mommersteeg’s research – also lost the ability to regenerate their heart tissue.

The fact that these two populations of fish have evolved differently gives BHF researchers a unique opportunity. It’s difficult to draw conclusions when we directly compare genetic differences between species (for instance, comparing cavefish genes and human genes). But because the river fish and cavefish are of the same species, it allows researchers to compare their genes side by side and find out the roles specific genes play in the body.

Dr Mathilda Mommersteeg in the lab

Dr Mommersteeg in her lab

What the researchers have found

Dr Mommersteeg and her team have found that the differences in heart repair between these two populations of fish are linked to differences in their DNA, in particular alterations in the gene lrrc10. The Mexican cavefish, which is unable to self-repair its heart, had a less active lrrc10 gene compared with the river fish.

Research in humans suggests that faults in lrrc10 are associated with an inherited heart condition called dilated cardiomyopathy, which causes heart failure.

What could this mean for heart patients?

Now, Dr Mommersteeg’s team is trying to understand how the differences in the lrrc10 gene between the river fish and cavefish lead to differences in heart regeneration and repair. This new information could help researchers find new ways to influence the lrrc10 gene, to develop new ways of repairing the heart after a heart attack.


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