There's some good news in the field of Alzheimer's Disease this week, and it comes from Japan. A team of scientists at the Tokyo Metropolitan Institute for Neuroscience have been hard at work on a vaccine treatment for this chronic neurodegenerative disease, and their results are published in PNAS online this week.
As with much in neurophysiology and -pathology, there are still substantial question marks over the exact mechanism of Alzheimer’s Disease, but it involves the build up of amyloid β peptides in the brain. These amyloid β proteins form plaques, that in addition to the neurofibrillary tangles, are believed to account for the loss of neuronal function and dementia. Therefore, one target for therapy has focused on helping the brain clear amyloid β instead of allowing plaques to develop.
Several groups have been working on such a therapy, notably Elan Pharmaceuticals, who were developing a vaccine to enable the immune system to target amyloid β, although their trials ended a few years ago following worrying side effects in some patients. This work also involves a vaccine approach, but unlike Elan’s attempt, instead of using amyloid β, it involves the use of a nonviral DNA vaccine.
The vaccine is in the form of a plasmid – a short loop of DNA. It is injected intramuscularly, and is used by the cells' internal machinery produce small amounts of amyloid β, which then stimulates the body’s immune system to produce antibodies against it. These antibodies can then be used to clear amyloid β build up in the central nervous system.
The results have been promising in mouse models of the disease, and the group hope that the DNA vaccine can be developed for use in man. As someone who lost a very talented relative to the ravages of Alzheimer’s, I hope that this is one therapy we hear a lot more about in the future.