Kiwis help with lab-grown retina
In what sounds like a gruesome sci-fi plot, Victoria University researcher David Ackerley is preparing to grow an artificial retina.
The biotechnologist, and others in a world-leading international team, hope it could help to cure one of the most common forms of vision loss.
The retina is a layer of light-sensitive cells at the back of the eye, connecting to the brain and allowing us to see. Though its cells consistently regrow themselves, this is an imperfect process - and some people are genetically predisposed to more frequent damage or the repair going astray, leading to degenerative blindness.
The "retina in a petri dish" will be grown from stem cells at Johns Hopkins University in the United States. Ackerley's team at Victoria and a second at Johns Hopkins will act as chefs, designing the ideal DNA recipe.
Having successfully grown a prototype healthy one, their next step is to make an unhealthy one that mimics degenerative blindness.
"Now you've got it working, the question is how do you make it stop working in a way that mimics degeneration [of vision]," Ackerley said. "The key thing is you want to leave most of the retina intact."
The international team has been given a US$500,000 (NZ$684,000) grant for this work.
The trick to knocking out specific visual cells was to add instructions to their DNA that made them die when exposed to an otherwise-harmless substance, leaving the cells around them unharmed.
Ackerley, with the Auckland Cancer Society Research Centre, is currently studying how transporting such DNA recipes into cancer cells could become a revolutionary new treatment. His team's experience in this made him ideally placed to join the international research.
Once they have grown the new retina, they will begin first by killing cells, then seeing what medicines help the retina to repair itself.
"I wouldn't say we've got a cure for blindness . . . It allows you to look in a way that can't currently be done for new drugs."
The example could be followed for studying diseases in other organs as well.
"This is a great system for just being able to look at the cells without harming any animals, and actually looking at the human response."
Assassins' recipe
Bacteria and human cells can have a vastly different reaction to a substance - it's why when taking an antibiotic the drug will kill bacteria without affecting us.
David Ackerley's DNA recipe instructions borrow from the bacteria cookbook, specifically the steps to make a certain enzyme. The original enzyme converts an otherwise-harmless substance into a toxic one, poisonous enough to kill a cell. Ackerley's lab has since turbo-charged it, making the enzyme highly efficient.
By inserting these instructions into the same page of the cookbook as the recipe for a visual cell means just these specific cells will use them.
Therefore, when the harmless substance is added to the artificial retina, the light-receptive cells will make the toxin while the recipe will stay inert and unused in all other cells, which will live.
- The Dominion Post