A new type of stem-like heart cell has been transformed into heart muscle, proving that dormant cells exist in the heart that have the capacity to carry out repairs, researchers from University College London reported in the journal Nature. The authors believe hearts damaged by a heart attack might be eventually encouraged to repair themselves.
At the moment there is no way of undoing heart damage caused by myocardial infarction (heart attack). The damage commonly leads to heart failure and poor prognosis – a problem which in the UK alone affects over 750,000 individuals.
The researchers targeted progenitor cells in the outer layer of the heart (epicardium). These EPDCs (epicardium-derived progenitor cells) in the embryo can turn into various types of specialist cells, including heart muscle ones.
Scientists had thought that the ability to transform is lost when the human becomes an adult. The authors explain that they have managed to reactivate this potential.
They treated the healthy hearts of adult mice with thymosin β4 (Tβ4), a peptide molecule, which appeared to prime the heart for repair – restoring the EPDCs’ embryonic potential.
When the heart became damaged, a Tβ4 booster was administered, encouraging the EPDCs to turn into new heart muscle and integrate with existing healthy muscle. The authors stressed that without being pre-treated with Tβ4, muscle is not formed.
Study leader, Professor Paul Riley at UCL Institute of Child Health, said:
“I could envisage a patient known to be at risk of a heart attack – either because of family history or warning signs spotted by their GP – taking an oral tablet, along the lines of a statin, which would prime their heart so that if they had a heart attack, the damage could be repaired.”
It will be several years before humans can be effectively treated in this way, the scientists wrote. Tβ4 only resulted in the generation of a small number of heart muscle cells to be generated.
The British Heart Foundation is funding further research into Tβ4. The aim will be to make it more effective, or perhaps find alternative ways to activate the embryonic potential of EPDCs, and eventually apply what they achieve in animal studies to humans.
Professor Riley said:
“This is an important piece of work and something we’ve been working toward for some time. Our earlier research proved blood vessels could be regenerated in adult hearts but there were major doubts about whether the same might be true for heart muscle. This work has demonstrated a possible method for repairing hearts damaged by a heart attack and could have a major impact on future therapies to treat heart failure.”
Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, said:
“To repair a damaged heart is one of the holy grails of heart research. This groundbreaking study shows that adult hearts contain cells that, given the right stimulus, can mobilise and turn into new heart cells that might repair a damaged heart. The team have identified the crucial molecular signals needed to make this happen.
These results strengthen the evidence that in the future there may be a drug, or cocktail of drugs, that could be given to people whose hearts have been damaged by a heart attack, to prevent the onset of heart failure. This is why the BHF has launched its Mending Broken Hearts appeal to raise money for research to turn this vision into reality for heart patients as quickly as possible.”
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