Gene Therapy Appears to Slow Alzheimer’s, Research Finds
A preliminary study at UC San Diego has found promising signs that using gene therapy to introduce nerve growth factor into the brain may retard the progression of Alzheimer’s disease.
The team, led by Dr. Mark H. Tuszynski, studied five women and three men, with an average age of 70, who were in the early stages of Alzheimer’s disease.
The study focused on determining the safety of the procedure and not its effectiveness. But in the process, the researchers found that the treatment delayed progression of the disease by 40% to 50% for at least two years, Tuszynski said.
By contrast, the Alzheimer’s drugs now available delay progression about 5% and the effects persist for about six months, he said.
“If the magnitude of these effects is borne out in larger, controlled trials, this could be a significant advance over existing therapies for Alzheimer’s disease,” said Tuszynski, who presented the results Tuesday at a San Francisco meeting of the American Academy of Neurology.
The team is already planning a larger follow-up study that will be overseen by Dr. David A. Bennett and Dr. Zoe Arvanitakis of the Rush University Medical Center in Chicago.
That trial will include 30 to 40 patients and will have a control group of patients who receive only sham surgery.
Results should be available in about a year and a half, Tuszynski said. If everything goes well, the treatment could be widely available in about four years, he added.
The approach is based on preliminary studies in rats and monkeys that showed that implanting cells that secrete nerve growth factor into the brain restored atrophied brain cells to near normal size and quantity, and also restored axons connecting the brain cells -- essential for communication between the cells.
The San Diego researchers collected skin cells from each patient, genetically engineered them to produce nerve growth factor, then implanted them through needles inserted into the center of the frontal lobe, which is important in memory and cognitive function.
One of the patients died five weeks later of a heart attack not related to the surgery.
The patients received standard cognitive testing before and after the surgery and their rate of decline was estimated by physicians.
The patients also underwent Positron Emission Tomography imaging, which showed a sharply increased metabolic rate in the region of the brain where the cells were implanted.
And finally, when surgeons autopsied the brain of the patient who died from a heart attack, they saw a marked growth response to the added cells, Tuszynski said.
The new clinical trial will use a simpler procedure that has proved equally effective in animal studies. Instead of using skin cells, surgeons will inject the vector -- the virus used to modify the skin cells in the earlier studies -- directly into the affected area of the brain, thus inserting the nerve growth factor gene directly into brain cells.
