"The trigger that's making all this possible is Calgary's expertise in isolating the specific blood stem cells we need," says Dr. Medin. "Without a sufficient quantity of those stem cells to work with, our likelihood of success would be greatly reduced."
In the Fabry trial, technologists led by Dr. Nicole Prokopishyn, director of the Calgary Laboratory Services Cellular Therapy Lab, processed the blood from a donor patient and isolated a specific type of stem cell called a CD34+ cell.
Christopher Armstrong, a 34-year-old Calgarian with Fabry disease, recently donated his blood for key initial experiments for the first phase of the trial. Nearly a billion of Christopher's CD34+ cells have been isolated and will be sent to Dr. Medin's lab in Toronto. Dr. Medin's team will take those cells and, using a modified virus, insert a working copy of the GLA gene into the stem cells.
"We use a type of virus called a lentivirus, which has been modified in a couple of critical ways," says Dr. Medin, who is also a professor in the Department of Medical Biophysics at the University of Toronto. "First, it's been stripped of any of its disease-causing capability and is safe. Second, it has the corrected functional GLA gene, which will cause the donor cells to make the correct enzyme. When the corrected cells circulate in the blood, they also secrete the enzyme, which is then taken up by unmodified cells. This effectively extends the therapy afforded by the modified stem cells."
The corrected cells go back into the donor patient, meaning there is less likelihood for rejection compared to cells coming from a different individual.
Like many other Fabry patients, Armstrong is currently on Enzyme Replacement Therapy (ERT), which requires a home care nurse to come to his house every two weeks to administer an
|Contact: Gregory Harris|
Alberta Health Services