Heart attacks strike about 70 000 Canadians annually, and some patients experience scarring after treatment.
“Scar tissue leads to stretching of the heart and that leads to consequences, including heart failure and early death,” according to Dr. Duncan Stewart, CEO and Scientific Director of the Ottawa Hospital Research Institute.
But stem cell therapy could lead to a more positive outlook for these patients: improved heart function, and thus better quality of life and longer life expectancy.
As Joanne Laucius reported in her September 5th Ottawa Citizen article “Ottawa research team leading study that allows heart to heal itself: ‘Enhanced’ stem cell clinical trial promises new era for heart attack patients,” Dr. Stewart is the lead principal investigator in clinical trials of stem cell therapy for heart attack patients.
[These clinical trials involve the use of adult stem cells and not embryonic stem cells. Embryonic stem cells come from a living human embryo which dies after the stem cells are extracted.]
Conditions such as high blood pressure and diabetes reduce the healing power of a heart attack patient’s stem cells, and so the trials involve extracting stem cells from the patient’s blood soon after the heart attack and enhancing them with extra copies of endothelial nitric oxide synthase, a gene vital to blood vessel function. Once returned to the patient through an infusion, the enhanced cells work to stimulate heart repair, reduce scar tissue and enable the heart to pump blood efficiently again. The process, from extraction to infusion, takes about six days.
Along with established cardiac treatment methods, one third of participants will receive genetically enhanced stem cells, one third will receive non-enhanced stem cells, and one third will receive a placebo. Neither the participants nor the researchers will know who receives which treatment.
While healthy people have heart function of about 60 percent, those who have had major heart attacks are at about 30 percent. Dr. Stewart believes the therapy could boost their heart function to 42 percent.
The trials will involve 100 patients who have suffered a major heart attack within the 30 days prior to their enrollment in the study and will last about two years, with results to follow six months to one year later. The first candidates will be those whose heart attacks caused the most severe damage. In the first year, about 25 patients will be recruited at the University of Ottawa Heart Institute and 25 at St. Michael’s Hospital.