On April 5, doctors at the University of California, San Diego, surgically implanted genetically modified tissue into the brain of a 60-year-old woman with early-stage Alzheimer's disease. The woman, who has requested anonymity, was discharged April 7 and is recovering nicely at home, her doctors say.
The experimental treatment includes steps that sound a lot like science fiction: Harvesting the patient's own skin cells, growing them in a petri dish, and transecting those cells with the gene that creates nerve growth factor — a substance required to maintain normal brain function. The final step is the most dramatic: During an 11-hour procedure, doctors drilled a hole in the right side of the patient's brain and implanted the cells.
Scientists hope that implanting the genetically altered tissue into the patient's right-side brain will improve — or at least guard against further degeneration of — the patient's memory, personality and spatial perception, all of which can be seriously affected by Alzheimer's disease.
What does this mean for Alzheimer's research in general? Dr. David Holtzman, a neurologist who studies Alzheimer's disease at the Washington University School of Medicine in St. Louis, spoke with TIME.com on Wednesday about last weekend's surgery.
TIME.com: This procedure sounds pretty radical. Do you have a sense of how significant it may turn out to be?
Holzman: We don't know how significant the treatment will be because this was the first patient to ever receive this type of gene therapy in the hopes of treating Alzheimer's — but there is a lot of data from animal studies suggesting that surgically implanting growth factor in the central nervous system can produce good results.
Why was such an extreme operation necessary?
Holzman: When it comes to introducing proteins into a human being, doctors have two options: You can infuse them into the brain (which requires a permanent pump), or you can choose gene therapy, as in this procedure. Gene therapy means you implant genetically modified tissue during a one-time procedure. Hopefully, those cells will produce the factor you are looking for.
These researchers injected cells only into the right side of this patient's brain because they wanted to use the untreated left side as a control. Could doctors eventually inject cells on both sides of the brain?
Holtzman: Yes. The site in question, called the nucleus basalis, which needs the nerve growth factor for normal brain function, is in the middle of the brain — so potentially, if the treatment worked, one could perform gene therapy on both sides of a patient's brain.
The doctors as UCSD are talking about performing another treatment on a new patient in six months or so, barring any negative developments. Would a simple lack of discernible results be enough to preclude further treatments?
Holtzman: No, no — there would have to be negative side effects to keep doctors from performing the procedure again. Doctors involved in this type of research know that testing this kind of treatment will have to involve many, many subjects over a long period of time.
So in other words, it could be a while until we know anything definitive about this treatment?
Holtzman:Oh, absolutely. It will be years before we see anything concrete.