Researchers around the world are working to develop effective treatments for dementia, and eventually to find a cure.
Much of this work is focussed on Alzheimer’s disease, the most common form of dementia.
There is currently no cure for Alzheimer’s disease. Available medications can reduce symptoms and improve quality of life in some people, but they do not stop the progress of the disease.
The potential treatments discussed below are in the early stages of research and are not currently available. However, they are all part of the research effort to find more effective treatments for Alzheimer’s disease and ultimately a cure.
Alzheimer’s vaccine and Immunotherapy
Researchers have been attempting to develop a vaccine for Alzheimer’s disease for almost a decade. The strategy behind the immunotherapy approach is to use the body’s own immune system to destroy beta-amyloid plaques.
The first Alzheimer’s vaccine was tested in clinical trials in 2001. However, the trial was prematurely halted because six percent of participants developed serious brain inflammation. However, the vaccination did appear to benefit thinking and memory in some unaffected participants who were monitored after the end of the trial. Researchers have now developed a safer vaccine by using antibodies against a smaller fragment of the beta-amyloid protein, which they hope will avoid the complications of the previous trial.
Another approach to developing a vaccine involves using immunoglobulin, a filtered human blood product containing antibodies. Immunoglobulin was shown to be successful in a very small trial of 8 people with mild Alzheimer’s disease, with most showing improvement on tests of cognitive function after treatment. Although this trial is very small, it suggests the potential for larger trials of immunoglobulin therapy, which may have safety advantages over other vaccination techniques. Although this initial research is promising, much more research needs to be done before we know whether this approach will work.
Gene therapy has been promoted as a promising technique for many different conditions. A very small trial of gene therapy for Alzheimer’s disease has shown beneficial effects - slowing the progression of the disease by about 50%. In this trial, genetically modified cells were injected directly into the brain. The cells were modified to produce nerve growth factor, a natural substance that helps brain cells to grow, survive and repair damage. Although the study is very preliminary, it indicates that gene therapy may provide beneficial treatment for Alzheimer’s disease in the future.
Targeting beta-amyloid production
Several treatment strategies for Alzheimer’s disease rely on targeting the production of beta-amyloid or its accumulation into plaques. One such strategy focuses on trying to inhibit the activity of enzymes which are involved in the production of the beta-amyloid protein.
The enzymes beta and gamma secretase act to cut amyloid precursor protein (APP) into several protein fragments, including beta-amyloid. These beta-amyloid fragments then aggregate into plaques. It may be the plaques or the fragments themselves or groups of fragments called oligomers that interfere with and damage nerve cells. Researchers are trying to develop drugs that inhibit these enzymes in order to reduce the production of plaque forming beta-amyloid. However, as both beta and gamma secretase have many other roles in the body, it has proven difficult to selectively inhibit their effects on APP and beta-amyloid in the brain.
Other strategies to stop beta-amyloid’s damaging effects include preventing its accumulation into plaques. Compounds that bind to beta-amyloid and help to clear it from the brain are being trialled. Zinc and copper are required for beta-amyloid fragments to form oligomers, so other compounds that target zinc and copper to prevent the formation of beta-amyloid oligomers are also being trialled. Vaccinating against beta-amyloid, as discussed above, is another approach under investigation.