Heart disease kills millions every year. It is one of the leading causes of death, because of how crucial heart is for our survival. However, situation is completely different for some animals. A tiny Mexican tetra fish is able to repair its own heart. Scientists from UCL and the University of Oxford say that humans can learn this ability and that someday it may be possible to heal heart muscle in people who have had a heart attack.
The Latin name of the tetra fish species in question is Astyanax mexicanus, but there are two distinctive populations – surface-dwelling population of Mexican tetra fish and their cave-dwelling counterparts. Despite sharing the same name, these two populations evolved very differently. The surface-dwelling tetras have the ability to regenerate their hearts after damage, but their cave-dwelling counterparts lost this ability. This is actually ideal situation for scientific research, because comparing genes from these two populations can reveal what allows some tetra fish to repair their hearts.
Scientists performed surgeries to remove parts of the hearts of some fish. Individuals from the surface-dwelling population later regrew the lost tissue, while the cave-dwelling tetra fish just formed a scar tissue. Hybrids between these two population showed different levels of regeneration, which proved that the ability to repair one’s heart is heritable in these fish. Then scientist used knockout models and quantitative trait locus analysis to analyse the regenerative role of lrrc10 gene. It is a mysterious gene unique to heart muscle that the fish shares with mice and humans, which may hold the key to the Mexican tetra fish’s remarkable ability to repair their hearts. Scientists managed to identify three DNA segments may play a role in heart regeneration.
Researchers think that further analysis may reveal how this heart repairing ability can be transferred to humans. Dr Yoshiyuki Yamamoto, co-senior author of the study, said: “Quantitative trait locus analysis is the method that has allowed us to find out what part of the surface fish DNA is most crucial for heart regeneration. We have identified three regions in the DNA that contain genes that make the difference between regeneration or scarring after heart injury”.
Scientists already know what they will focus on in the next steps of the study. They are going to try and find why cave-dwelling Mexican tetra fish cannot repair its heart while its surface-dwelling counterpart has this ability. Maybe soon heart attack patients will be able to enjoy fruits of these studies.