Fish genes hold key to repairing damaged hearts

London : Scientists have identified a gene behind the Mexican tetra fish's ability to repair its damaged heart, an advance that may hold clues for future treatments in humans. Researchers at the University of Oxford in the UK found that the tetra fish living in the rivers of Northern Mexico have retained their ability to repair their heart tissue even after millions of years. However, the fish in one particular cave, called Pachon, have lost this amazing ability. 

The study, published in the journal Cell Reports, compared the genetic code of the river fish to that of the cave fish to discover what special mechanisms are required for heart repair. The researchers found three areas of the fish genome were implicated in the fish's ability to repair their hearts. They also compared the activity of genes in the river versus the cave fish in the period after heart injury. Two genes, lrrc10 and caveolin were much more active in the river fish and could be key in allowing the river fish to repair their hearts. Lrrc10 is already linked to a heart condition called dilated cardiomyopathy (DCM) in people, researchers said. 

Studies in mice have previously shown that this gene is involved in the way that heart cells contract with every heartbeat, they said. The team studied the effect of this gene in the zebrafish, another fish which has the remarkable ability to heal its own heart. When the researchers inactivated the lrrc10 gene in zebrafish they saw that the fish could no-longer fully repair their hearts. During a heart attack, the heart is deprived of oxygen leading to the death of heart muscle cells and their replacement by scar tissue. This stops the heart muscle from contracting properly and reduces the heart's ability to pump blood around the body.