Canadian researchers are trialling a technique that uses genetically enhanced stem cells. Taking a blood sample from patients soon after a heart attack, they can harvest cells known as endothelial progenitor cells that have the ability to form new blood vessels. These are then injected into the heart, where it is hoped they will help muscle to regenerate.
However, cells from patients with heart disease may not be as effective at forming new tissue, so the team plans to add a gene that stimulates blood vessel growth and improves tissue healing, known as endothelial nitric oxide synthase.
'Our strategy is to rejuvenate these stem cells by providing extra copies of a gene that is essential for their regenerative activity, so that they better stimulate heart repair, reduce scar tissue and restore the heart's ability to pump blood efficiently - in other words to help the heart fix itself', said Dr Duncan Stewart, lead investigator of the trial at the Ottawa Hospital Research Institute.
The first patient to be treated on the Canadian trial is 68-year-old Harriet Garrow, who suffered a heart attack in July 2013. Garrow received one of three treatments as part of the randomised double-blind trial – either normal stem cells, genetically enhanced stem cells, or a placebo injection of her own blood plasma. She told the Huffington Post: 'I feel really good. I get better every day, stronger'.
In the UK, another trial reported in BioNews 703 has begun testing in patients. Researchers at Imperial College London will deliver the SERCA2 gene into people with heart failure using a carrier virus. The gene expresses a protein involved in calcium signalling, which allows the heart to pump more effectively.
Dr Alexander Lyon, consultant cardiologist at Royal Brompton Hospital, told the BBC: 'Importantly, early trials suggest the treatment is safe. But we need this large study before we can be sure the gene therapy really works. If we could find an effective treatment, that would be very exciting'.
The Canadian trial will last a further two years, with the trial in the UK due to end in three years.