Alzheimer's disease

Apart from familial Alzheimer’s disease, the cause of Alzheimer’s is not currently known. A major risk factor is age, although the reasons for this are not well understood. A variety of suspects, including environmental factors, biochemical disturbances and immune processes are being investigated, although it is most likely to be a combination of factors that cause the disease. It is known, however, that head injury, particularly repeated trauma, increases the risk of developing Alzheimer’s disease. Poor cardiovascular health and smoking have also been linked to the disease. A genetic mutation on the ApoE gene is implicated in Alzheimer’s and this gene, along with several other genes, is under investigation.

The symptoms of Alzheimer’s disease are caused by the loss of nerve cells and pathways in the areas of the brain that are vital to memory and other mental abilities. Plaques which contain misfolded proteins called beta amyloid form in the brain many years before the clinical signs of Alzheimer’s are obvious. Another protein called tau, abnormally aggregates in the brain cells causing them to die. It is not known if this pathology, which is used to definitively diagnose Alzheimer’s disease after death, initiates the disease or results from the disease.

What are the symptoms of Alzheimer’s?

Alzheimer’s disease begins slowly, with the first symptoms usually being mild forgetfulness and visual-spatial confusion. However, as the disease progresses, these symptoms may begin to interfere with daily activities, such as navigating through familiar areas or recognising people or objects.

In the middle stages of the disease, people with Alzheimer’s may have difficulty doing basic tasks like brushing their teeth, speaking, reading and writing. Patients may become anxious, agitated or aggressive and will eventually need total care. In the last stages of the disease, deterioration of musculature and mobility occurs. Patients become bedridden and death ensues, often from pneumonia.

There is currently no single test to identify Alzheimer’s disease. A thorough neurological examination including testing of memory and intellect is given along with other tests, such as blood tests, to rule out the possibility of other diseases such as depression or nutritional deficiencies. Once diagnosed, the symptoms of Alzheimer’s disease are managed with a variety of treatments including drug therapy and lifestyle modifications. Current drug treatments appear to provide some stabilisation in cognitive function for some people with mild to moderate Alzheimer’s disease, but they do not alter the progression of the disease. Drugs may also be supplied for secondary symptoms like depression or sleeplessness.

Together with drug therapy, cognitive and behavioural interventions such as counselling or psychotherapy may also prove helpful throughout the disease. Lifestyle and environmental modifications can also be very beneficial to both the person with Alzheimer’s disease and their carer. Activities of daily living can be aided by adhering to simplified routines and labeling of household items to help cue the patient. Changes in routine or environment can trigger or exacerbate agitation, whereas adequate rest and avoidance of excess stimulation can help prevent episodes.

The Garvan Institute is taking a range of approaches to investigate Alzheimer’s disease. Our scientists are researching the mechanisms at the synapses (where one neuron makes a connection with another) that are important in memory formation and trying to understand if these mechanisms are somehow involved in contributing to neuronal death in Alzheimer’s disease.  In particular, we focus on signalling pathways regulating neuroplasticity, or the ability of the brain to change or ‘re-wire’ itself.  This process is uniquely advanced in humans and defects can lead to neurodegeneraive disorders.  We have mapped new pathways controlling neuroplasticity and are currently determining if they are dysregulated in the brains of Alzheimer’s patients.  The goal of this work is to identify novel therapeutic targets or biomarkers that can be used for early and specific detection of Alzheimer’s Disease.

Another of our research projects involves the possibility of harnessing the brain’s own adult stem cells, which normally function to repair injury to the brain and make new nerve cell connections, to help treat Alzheimer’s disease and other neurodegenerative conditions. We have identified a molecule that is able to stimulate neurogenesis, which would underpin brain repair. This is important because it is believed that brain repair could provide part of a cure for neurodegenerative diseases. We now have an enormous amount of work to do to understand how this molecule acts to bring about this regeneration, determine if the molecule has any therapeutic potential, and identify other molecules that may be important for stimulating regeneration and stem cell therapies.

This content is provided for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. If you have any concerns or questions about your health, please consult a suitably qualified healthcare professional.