Recently, with a kind of virus researchers have imported a specific gene into the brain to stop the worsening of senile dementia in small mice. This research was sponsored by Alzheimer's Research UK and European Research Council. Related research results were published on the journal PNAS on October 10.
         In China, there are already around 7 million Alzheimer patients. By 2030, the figure will grow to 16 million. Symptoms of the disease include loss of memory, bewilderment and changes of emotions or personality. Across the world, 47.50 million people are affected by dementia, among which senile dementia is the commonest form. At present there is still no method to cure senile dementia, while drugs can only help ease the symptoms of the disease.
         Recently scientists of Imperial College London have opened a new path for the treatment of the disease. They used a kind of improved virus to transplant a PGC1-α gene into the brain cell. In the lab, the gene can stop the formation of β- amyloid protein in the cell, thereby stop the worsening of senile dementia in small mice. (β- amyloid protein is the main component to trigger the death of brain cells of a patient of senile dementia)
         Professor Nicholas Mazarakis explained, "The improved virus used in the experiment is called lentiviral vector, which is commonly applied in gene therapy. By infecting cells with the lentivirus, scientists have created a modified virus to import the gene into specific cells. It's used in the experiment to treat a series of diseases ranging from arthritis to cancer. Previously we have managed to transplant the gene to the brain of a patient of Parkinson disease by using the lentiviral vector in the clinical experiment."
         In the new research, the team has injected virus containing gene PGC-1α into the two brain areas of small mice which are vulnerable to Alzheimer disease. The targeted areas are hippocampus and cortex, for these areas are the areas where amyloid protein plaques are formed in the case of Alzheimer disease.
         At the early stage of senile dementia, the animals received treatment, when there were still no amyloid protein plaques. Four months later, the research team found that compared with the small mice that were not treated, the mice receiving the gene showed very few amyloid plaques, while the brain of the former was found to contain a few plaques.
         Besides, the mice receiving treatment had a similar performance as healthy mice in memorizing tasks which included some challenges, like, a familiar object in the cage of mice was changed to a new one. If the mice had a healthy memory, they would explore the new object for a long time.The research team also found no loss of brain cells in the hippocampus of the mice that have received gene treatment. In addition, the neurogliocyte cells of mice that have been treated have decreased. In the case of senile dementia, this type of cells may release toxic inflammatory substance, which will further damage the cells.
         Protein PGC-1α is encoded by PGC-1α gene and is involved in the metabolism process, including regulating the metabolism of sugar and fat. Dr. Sastre added, other researches from different institutions indicate that physical training and chemical compound resveratrol--existing in red wine may also increase the level of PGC-1α protein. However, researches find that resveratrol is only helpful when it's taken as drug, rather than absorbed from the wine, for the alcohol will offset any benefit it has brought. The research team suggests that the injection of such gene is most helpful at the early stage of the disease when the first symptom appears.
         Dr. Sastre said, now they wish to explore how to apply their research fruits in the treatment of human. "We still need several years before clinical application is realized. However, for a disease that is in urgent need of new choices, this work will bring hope to the therapy in the future."
         Dr. David Reynolds, Chief Scientist of British Research Center of Alzheimer's Disease, said, "At present there is still no treatment that can stop the worsening of senile dementia. Therefore, researches like this are very important, which can find new and innovative methods and help us get closer to this goal. This research has laid down the foundation for the exploration of gene therapy as a treatment strategy for Alzheimer's disease. However, further researches are required to confirm whether it's safe, effective and pragmatic to apply gene therapy in patients of this disease. These research results support the use of PGC-1-α as a potential target for new drug development. This is a gratifying step forward in the path of developing treatment methods for this destructive disease."