Early and limited application of a newly developed gene therapy has given researchers hope that certain Alzheimer’s patients can be protected from the vicious ravages of the disease.
If further trials prove successful, scientists believe that by injecting a gene into people’s brains, they can prevent the disease from progressing in some patients and even completely block it from affecting individuals with high risk factors who have yet to be touched by the disease.
News of the early trial—only five patients were involved—was presented at last year’s Clinical Trials on Alzheimer’s Disease Conference. Scientists not involved in the test seemed encouraged by the presentation.
“It’s a very provocative, very intriguing approach,” said Dr. Eliezer Masliah, director of the neuroscience division at the National Institute on Aging.
What was particularly noteworthy was that the gene therapy seemed to lower the levels of tau and amyloid in the brain of the five patients. Those are two proteins that scientists have pegged as possible triggers of Alzheimer’s. Only a low level of the gene was injected into their brains, but it was sufficiently promising that a second trial is being conducted with a higher dosage of the brain being administered.
The gene therapy was aimed at Alzheimer’s patients with a genetic risk for the disease.
Dr. Ronald Crystal, chairman of the department of genetic medicine at Weill Cornell Medicine in New York, has been a key figure in the trial therapy. His company, Lexco Therapeutics, is backing the study, along with the non-profit Alzheimer’s Drug Discovery Foundation.
Patients taking part in the study have inherited copies of APOE4, a gene that is seen as a major risk factor for Alzheimer’s. Despite being aware of the APOE4 risk factor for decades, researchers have not been able to make headway in combatting it. This has frustrated scientists seeking to find a way to conquer Alzheimer’s, and the new study has given them a fragment of optimism, even if it only seems to be relevant for those with two pairs of the APOE4 gene.
Those five patients in the initial study had the APOE4 gene and also had been experiencing the first symptoms of the disease. Researchers do not understand why this gene is a marker for Alzheimer’s. Nor do they know why some individuals inheriting two copies of APOE4 do not contract the disease.
Other genre variants that have been identified as being markers signaling the likelihood—or unlikelihood—of Alzheimer’s are APOE2 and APOE3, and it is the combination of those genes—all individuals inherit two—that determine the probability. Scientists have found that the probability is increased when an individual has two copies of APOE4 gene and decreased when two copies of APOE2 are in the brain.
A major area of interest has been to inject APOE2 into the brain of those with two copies of the APOE4 variant, thus potentially cutting in half the likelihood of getting Alzheimer’s, according to researchers. Unfortunately, efforts to develop such programs have not progressed very far up to now, at least in part because of the difficulty in finding individuals willing to participate in the research.
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