One hundred years of research on Alzheimer’s disease

By Monique Villemaire, Federation of Quebec Alzheimer Societies

Since the discovery of Alzheimer’s disease 100 years ago, important progress has been made in the field of biomedical research. During the last twenty years in particular, our understanding of the illness has evolved considerably, and the development of new treatments has led to improvements in the quality of life of people with the illness and that of their families.

Dr. Serge Gauthier is an international leader in the field of neurology whose work has offered much hope to those impacted by Alzheimer’s. A professor in the departments of Neurology & Neurosurgery, Psychiatry, and Medicine at McGill University in Montreal, he also holds a research chair at the Canadian Institutes of Health Research (CIHR) and is Director of the Alzheimer Disease Research Unit of the McGill Centre for Studies in Aging.

Dr. Gauthier says the 1960s were a turning point for the recognition of the disease. “Following the discovery of a deficiency of one of the neurotransmitters of the brain, acetylcholine, there was renewed interest in Alzheimer’s. Around the same time, it was noticed that the illness could manifest itself at different ages in a person’s life.

These discoveries led researchers to take an interest in a group of cells responsible for the manufacture of the acetylcholine that they felt could underlie appearance of the illness,” he explains.

“As it turned out, that wasn’t the case. Subsequent research showed that neuron connections were damaged by conditions like cerebral arteriosclerosis, the thickening and hardening of the wall of arteries in the brain. Current research shows that every person 75 years or older who is diagnosed with Alzheimer’s disease also has a little cerebral arteriosclerosis.”

There are several research pathways, continues Dr. Gauthier, that could lead to a cure for Alzheimer’s, but there is no medication at present that can stop the disease or slow its progress. “Treatments available today allow for the control of certain symptoms. We usually see improvement in concentration and spontaneity, and greater interest in participating in activities. We also notice less anxiety and fear.”

“Generally speaking, the medications help maintain functional independence,” he continues. “The effect on symptoms lasts an average of a year or two. After that we find a progressive loss of effectiveness. Fortunately, a medication exists (memantine) for treatment of moderate to severe Alzheimer’s disease. It can be used during the third year, in the moderate stage of the disease, for most patients still at home.”

He adds that unlike cholinesterase inhibitors, which help prevent a cholinesterase enzyme from breaking down acetylcholine, memantine helps control glutamate, a neurotransmitter produced in overly high quantities at the moderate to severe stages of the illness. “In the latter stages of the disease, memantine can lessen the severity of certain symptoms.”

Dr. Gautier says that beyond positive effects on cognition, mood, behaviour, and the ability to perform daily activities, there is also generally an improvement in the ability to communicate verbally. People speak more easily, the words come more easily. Memantine can also help control agitation, or prevent it if it is not already present. It does not, however, improve memory or the ability to get around at home. The effects on agitation and the ability to communicate are nonetheless very much appreciated. Its use may even eliminate a need for tranquilizers in certain cases.”

Dr. Gauthier also points to the contribution of new technologies – brain imaging in particular – to research. “We’ve come to realize that people were often diagnosed with Alzheimer’s disease due to aging, when they actually had a vascular component (cerebral arteriosclerosis). We know now that only through a CAT scan of the brain can we determine if it’s pure Alzheimer’s, Alzheimer’s disease with a vascular component, or if it’s just arteriosclerosis.”

According to Dr. Gauthier, the development of a treatment able to stabilize the disease can be expected in the fairly near future. “We hope to succeed in intervening with the causes of Alzheimer’s disease, which vary from one age group to the other.”

“Targeted treatments will be refined based on a person’s family history and their symptoms at a given time. A medication (Alzhemed) is currently being tested in North America and in Europe. Its aim is to check the progress of the illness at the mild to moderate stages of the disease, when amyloid is very important.”

“There is promising research under way in immunotherapy as well. It consists of injecting an antibody intravenously with an aim to eventually eliminating amyloid deposits. We don’t know if that will allow for reversal of the fog or simply halt the progress of the illness at the stage where it was at the start of treatment – nothing has been demonstrated yet.”

Dr. Gautier adds that other drugs that manage cholesterol levels in the blood are being tested. “An existing medication for the treatment of cholesterol is currently being tried with people who have Alzheimer’s disease and a normal cholesterol rate.”

He also explains that “other research is exploring the ability of the brain to repair itself. We know that the brain has the potential to recover from damage caused by a blow to the head, arteriosclerosis, an epileptic seizure or Alzheimer’s disease – even in an older adult.” Results from these various studies will be available between three and five years from now.

Dr. Gauthier says it’s possible to help prevent this illness by adopting healthy living habits. “The risk factors are well known. We know that following a balanced diet, one that includes folic acid and omega-3 fatty acids, watching your blood pressure (especially between the ages of 40 and 60), drinking moderate amounts of red wine, exercising, remaining active after retirement, living with someone if possible, and feeling socially useful are all things that keep our brains active and healthy.”