Mohamed Yousuf BHUGUN (DMLT, MSc (UK), FIBMS.)

International Liaison Officer ( North America) / Research Scientist

Email: ybhugun@yahoo.com

Alzheimer’s disease has become one of the leading disorders in most developed countries including Europe and North America. It is estimated that about 4.5 million of North Americans, nearly 240,000 of Canadians and more than 800,000 of the UK population are affected by this disease. Most of the victims are over the age of 60.

The disease is characterized by an accumulation of biochemical compounds known as amyloid beta-peptides in the brain forming amyloid plaque deposits. The symptoms range from forgetfulness to dementia and most people die within 10 years of diagnosis. The patients also have twisted strands of fibre inside their brain cells where the tau proteins are strongly believed to be responsible for the tangling process.

A team of Canadian scientists has recently produced a vaccine called as AN-1792 that may help to prevent and treat the disabling memory loss and cognitive impairment. The researchers at the University of Toronto’s Faculty of Medicine have found that immunization with amyloid b -peptides blocked both the production of the plaques and learning impairment. The vaccine was not only able to clean up the brain tissue but also prevented the behavioral consequences of the disease.

In the experiment, mice were genetically engineered to form amyloid plaques in their brains. Half of the mice were vaccinated with the vaccine and the others with a placebo. After 23 weeks, the vaccinated mice performed significantly better at a test of spatial memory test called the Morris water maze test. The next step is to conduct preliminary trials on the safety of the vaccination before larger scale testing can begin in its therapeutic effectiveness. Currently, researchers at San Francisco based Elan Pharmaceuticals are testing the vaccine on the healthy subjects for any serious side effects. The vaccine can then be tested on patients with the disease.

But the scientists are cautious about the effectiveness of the vaccine on humans. This is because the laboratory mice cannot mimic the neurofibrillary tangling seen in humans. So, clinical trials in real patients will be critical to proving the effectiveness of the vaccine. As amyloid b -peptide is part of a protein that occurs naturally in the human body, the big risk is that the antibodies may cause harmful effects in other parts of the body.

Over the past decade, researchers at the University of Toronto’s Center for Research in Neurodegenerative diseases have made a number of fundamental discoveries on this disease. In 1990, they were the first to show that Alzheimer’s is complex disorder with many causes, some of which are genetic. In 1995, two defective genes that cause aggressive early-onset forms of the disease namely Presenilin 1 and Presenilin 2 were identified. Recently, a new gene was discovered named as Nicatrin which is involved in amyloid peptide production.

Scientists believe that if this vaccine is successful for Alzheimer’s disease, similar ones can one day be found for other protein-related diseases. These include the Creutzfeldt- Jacob disease (CJD), Parkinson’s disease and myeloma.