Scientists restore muscular dystrophy genes in dogs
Scientists at London’s Royal Veterinary College and UT Southwestern Medical Center in America have been able to restore the key protein people with Duchenne muscular dystrophy are unable to produce in dogs.
The condition which affects about 2,500 young men in the UK can also be found in canines.
Before animal rights activists start freaking out, the method involved injecting one month year-old puppies with two harmless viruses which altered the dogs’ chromosomes around the muscles and heart using the Crispr gene-editing - a tool which helps scientists edit a quirk in the immune systems of bacteria quickly and cheaply.
After a few months the protein was restored improving the heart by 92% and the diaphragm by 58 per cent.
Although the result still isn’t productive enough for humans – experts say it needs at least 15% more efficiency – it’s a breakthrough to finding a possible cure for the illness.
Dr Eric Olson from UT Southwestern said: "Children with DMD often die either because their heart loses the strength to pump or their diaphragm becomes too weak to breathe.
"This encouraging level of dystrophin expression would hopefully prevent that from happening."
Professor of comparative neuromuscular disease at the Royal Veterinary College, Richard Piercy, said: "The ambition is to show that this is safe and effective in dogs and then move into humans’ trials.
"If that works, then the treatment could also apply to pet dogs that we see in our clinics - and that's what we hope for here at the college, as it's our goal to make animals better."
A similar set of trials have been carried out in mice, although this is the first time the method has been tested on a larger mammal with the intention that the next stage will involve humans.
The study on dogs was used to restore genetic faults which affect around 13% of people with DMD, but it’s hoped the method will be effective on those with other forms of the condition.
Lead author of the study, Dr Leonela Amoasii, said: "Our strategy is different from other therapeutic approaches for DMD because it edits the mutation that causes the disease and restores normal expression of the repaired dystrophin.
But we have more to do before we can use this clinically."
Despite the success rate in the study independent experts point out that there was limitations and only a handful of dog breeds were used.
Professor of genetics at the University of Kent, Darren Griffin, said: "This work represents a small, but very significant step towards the use of gene editing for DMD.
"Any steps towards significant treatment regimens can only be good news. In the fullness of time, this paper may well be seen as one of the ground-breaking studies that led the way to effective treatment."
Dr Kate Adcock from Muscular Dystrophy UK added: "The next step will be to conduct larger, longer-term studies to see if the gene editing approach does help to slow the progression of the condition and improve muscle strength.
"This won't be a cure - but that shouldn't obscure that this is a key step forward in proving the Crispr technology could work for Duchenne."
In 2016 a document revealed a series of errors resulted in injuries and deaths of animals at the Royal Veterinary College.