The operation was the first attempt to do gene therapy for Alzheimer's, and it took 11 hours to perform. It was designed primarily to determine whether the procedure is safe enough to test further. The goal is to bolster a group of neurons called cholinergic cells located at the base of the forebrain. These brain cells play a critical role in our ability to reason and process information, but they are just one of several kinds of cells that degenerate during the course of the disease.
Animal studies have already shown that a protein called nerve growth factor is vital to keeping cholinergic cells healthy. Using gene-therapy techniques, the San Diego team transformed samples of their patient's skin cells into NGF mini-factories. They then implanted the modified cells into their patient's brain. If all goes well, the deterioration of the cholinergic cells could slow or even stop.
That's a mighty big if. No one knows why cholinergic cells die in Alzheimer's disease, Tuszynski notes. Boosting NGF levels might not be enough to keep the cells alive. And having healthy cholinergic cells around might not matter when so many other cells in the brain are dying. Researchers are only just beginning to understand the complexities of Alzheimer's disease. A single operation can't provide all the answers.