October 10, 2013 5:38 pm
Updated: October 10, 2013 8:14 pm

Experimental trial at U of A could restore vision loss

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EDMONTON- A new experimental trial is about to get underway at the University of Alberta that could potentially treat or improve vision loss.

The trial, led by Alberta researchers Dr. Ian MacDonald and Dr. Tania Bubela, is the first of its kind in Canada and only the second in the world. The gene therapy trial hopes to improve the vision of those who suffer from choroideremia.

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“I was told when I was younger, ‘you’ve got a retinal disease.’ So that sounded kind of bad to me. And the next part is it leads to blindness, that sounds really serious. And then the third part was, which was the real kicker, is that we can’t do anything about it. Nothing can be done,” said Mark Huyser-Wierenga who was diagnosed with choroideremia in his early 20s.

Choroideremia is a rare genetic eye disease that affects about one in 50,000 people- mainly men. It causes the photo receptor cells in the retina to slowly die from the outside in.

“Patients, they start to experience night blindness in their, maybe, late teens, early 20s. And then they progressively lose their vision from the outside, resulting in tunnel vision through adulthood,” explained Bubela.

“I appear to be clumsy, I walk into things, bump into things. I can’t navigate smoothly. In a crowded situation I tend to go to the outside walls… I can’t make my way through a crowd. I’ve had to give up cycling to work,” said Huyser-Wierenga, of how the disease has impacted his life. “That’s my reality.”

Not only has choroideremia impacted his life, Huyser-Wierenga is worried about how it could affect his children’s lives.

“I’ve got three daughters, so the likelihood of it occurring down the generational line is so high, you know, it’s a big burden on them.”

People with choroideremia have a faulty gene, and the goal of the experimental trial is to replace that malfunctioning gene with a functioning copy of the gene.

“So you take a virus and you remove its nasty properties, so its properties that make it cause disease, but you piggyback on that virus’ ability to deliver genetic material into a cell. So you take that virus and you insert the functional copy of the gene and then that virus acts as a delivery vehicle for the functional copy of the gene into the cell,” Bubela explained.

“It’s not going to bring cells back to life, but it is going to restore functions in cells that are on their way to dying,” she added. “The reason this is very exciting is this is a very experimental and new potential treatment for blindness.”

“It’s a wonderful experience to be able to link patients who have been expectantly waiting for something like this to happen,” added MacDonald.

Local physicians have already travelled to the UK- where a similar trial was conducted at Oxford University- to learn the virus-injecting technique. Eight patients took part in that trial and had positive, encouraging results.

“People’s sight is improving. I mean, not back to full robust 180 degrees, 150 degrees, but any improvement is so precious,” Huyser-Wierenga said. “Some people are saying, you know, ‘I haven’t seen the stars for decades, I can see stars again.'”

Huyser-Wierenga is hoping gene therapy could one day help his vision and help him once again enjoy the simple things in life.

“Simple pleasures that I can’t do easily… holding a book or a newspaper, opening it up and just reading without struggling,” he explained. “There is so much joy wrapped up in that from my perspective.”

The team at the U of A has been granted $5 million by Alberta Innovates Health Solutions. They are now looking to recruit 12 people with choroideremia for the trial.

With files from Su-Ling Goh, Global News.

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