The headline on the New York Times article rightly described the news as a “breakthrough”. The news was that two scientists, Doo Yeon Kim and Rudolph E. Tanzi of Massachusetts General Hospital, had developed “Alzheimer’s in a Dish” — a petri dish with human brain cells that develops the characteristic plaques and tangles of Alzheimer’s.
Why is this a breakthrough and why is this of interest to people with Parkinson’s?
It’s a breakthrough because, as one researcher quoted in the article said, “It could dramatically accelerate testing of new drug candidates.” Even if there were not ethical issues in initially testing new drugs on humans, getting sufficient human volunteers is always a challenge. So proposed drugs to treat Alzheimer’s are currently initially tested on mice. However, mice turn out to have only a rough simulation of an Alzheimer’s progression. After researcher’s put human Alzheimer’s genes in mice, the animals make excess beta amyloid proteins like humans with Alzheimer’s and develop plaques, but don’t develop “tangles”, an essential component in human Alzheimer’s. Presumably as a result of mice being only an approximate model, more than 20 drugs that seemed to cure Alzheimer’s in lab mice utterly failed when tested on humans.
The “Alzheimer’s in a Dish” had the three principal components: the excess beta amyloid proteins, the plaques, and the tangles all formed a few weeks after human brain cells in a lab gel were implanted with a gene known to cause Alzheimer’s So the scientists have created a methodology that is not only closer to the human model than mice, but can be quickly replicated to rapidly test hundreds of drugs.
Why is this of interest to persons with Parkinson’s?
Not only is Parkinson’s theorized to have a similar excess protein causation (albeit a different protein, alpha synuclein), but it too has only a rough animal model. (See previous post.) Parkinson’s researchers have been developing “Parkinson’s in a Dish” as far back as 2008. This press release from Howard Hughes Medical Institute describes converting cells from individuals with the diseases into stem cells with the same genetic errors, for several diseases, including Parkinson’s. (A small percentage of Parkinson’s patients have genetically caused disease.) The next step was described in a press release from Stanford University from 2011: stem cells were derived from the skin of a woman with a genetic form of Parkinson’s disease, then the stem cells created neurons which replicated some key features of the condition in a dish. This research also validated the use of induced pluripotent stem (IPS) cells to model Parkinson’s, among other diseases. IPS cells are adult stem cells derived from skin cells, as opposed to embryonic stem cells.
So where’s the big flood of new Parkinson’s drugs being tested on “Parkinson’s in a Dish”? I don’t know. Sounds like a good question to bring up at the “HOPE Conference” I just signed up for, the annual Northwest regional conference on PD. See you on November 1.