Gene therapy to try to apply in order to prevent Alzheimer's disease
No one knows for sure what causes Alzheimer's disease. But one fact about the disease has acquired virtually irrefutable status. Depending on which version of the APOE gene, you inherit the risk of a brain disease may be two times lower than the average - or 12 times higher. APOE is sometimes called "gene forgetfulness", and it is three versions: 2, 3 and 4. Version 2 reduces the risk for humans; 3 - medium index; 4 - increases the risk dramatically.
The risk is so great that doctors avoid checking APOE status as a bad result can upset people - and there's nothing you can do. No treatment, and the genes can not be changed.
Or can you?
Is there a cure Alzheimer's genetic?
While we can not. But doctors in New York say that since May, they will begin testing a new gene therapy, in which people with the APOE gene unsuccessful will be given a huge dose version, which lowers the risk.
If it helps to slow down the depletion of slow brain disease for people who already have Alzheimer's, eventually it will lead to the possibility of preventing the disease. The clinical trial, which was led by Ronald Crystal of Weill Cornell Medicine in Manhattan, represent a new tactic against dementia, as well as a new twist in gene therapy. Most efforts to replace genes which rely on viruses carrying DNA into human cells instructions aimed at the elimination of rare diseases such as hemophilia, by replacing a defective gene.
But common diseases are no such single reasons why gene therapy has never been particularly promising. The trade group Alliance for Regenerative Medicine states that there are currently no gene therapy is not performed on patients with Alzheimer's. "It seems that the way to human clinical trials will be long, but there is an acute need for any treatment," says Kiran Musunuru, Medical School, University of Pennsylvania professor. He studies the genetic treatments for cardiovascular disease, and says that the experiment planned in New York, is a new category of gene therapy, the aim of which is not to cure, but to reduce the risk of future disease in healthy people.
Crystal says that his plan also shy away from debate about the true cause of Alzheimer's disease, which has become a field of dreams with multi-billion dollar, which lose and pharmaceutical companies and patients. In January Roche stopped two large studies of antibodies that have been clarified properties of beta-amyloid plaques, the last of the theories which claimed that these plaques around neurons give rise to Alzheimer's.
"In the area there are many who firmly believes that the blame for amyloid," says Crystal. Others believe that the blame for another protein - tau - which tangles found in dying neurons. "The answer is likely to be difficult to find. The approach we have chosen to ignore all of this and considering the situation from the genetic point of view. "
In this case, Krystal team relies on 25 years of opening. In the 1990s, scientists from Duke University were looking for proteins that could be attached to the amyloid plaques. And they identified apolipoprotein-E, which is encoded by the gene APOE. Sekveniruya this gene in 121 patients, they found that a separate version - APOE4 - inexplicably was distributed to suffer from this disease. The function of this gene is still not well understood (it plays a role in cholesterol transport and fats), but its status as a risk factor remains daunting. According to the Alzheimer's Association, about 65% of people with Alzheimer's disease have at least one copy of the dangerous gene. For people born with two copies of the high-risk, one from each parent, dementia is almost guaranteed, if they live long enough.
However, some people inherit a 4 and a 2 version of the gene with a low risk. These people are closer to the average risk, suggesting that the protective version of the gene compensates risky.
It is this effect, doctors will try to copy the Weill Cornell. Currently the center is looking for people with two copies of the high-risk gene that has lost memory or even have got Alzheimer's. According to Krystal, the first about a month, volunteers will receive an infusion into the spinal cord of a billion viruses carrying a gene 2.
Based on tests on monkeys, Crystal expects that the virus has spread the "happy gene" in cells throughout the patient's brain. Mice were treated in the same way, and rodents have accumulated less amyloid in the brain.
This strategy, according to the researcher, does not depend on the knowledge of all that really causes the disease. "In Alzheimer's we are attracted by the apparent genetic epidemiology," he says. "So, the strategy is whether we can bathe the brain in E2? We have the infrastructure for this, so we thought, why not? This solves the problem of the mechanism of the disease. "
"The concept is rational," adds Crystal. "Will it work with a man - is another question."
The New York study is preliminary. Crystal says that his team needs to determine gene function and added to a level where it can be detected. Physicians taken from the cerebrospinal fluid of patients and is checked whether it contains the expected mixture of proteins - the expected type 4, but now with an equal or greater amount of the kneaded 2.
By the time when people start to forget names and where the car keys, the changes in the brain have been held for ten years. This means that patients who are connected to the study, can not count on much. For them it will be too late.
Despite this, fundraising cure Alzheimer issued Crystals $ 3 million on research. In the end, the hope is that middle-aged people with genes at risk will be subject to a single genetic adjustment. Even a small reduction in speed with which changes occur in the brain, may eventually change the situation.
Well, let's hope that everything will turn out. We suggest to follow the news on our news channel.