Our Sense of Smell and Dementia

August 27, 2014

A sudden loss of sense of smell is not only alarming – it can sometimes be considered one of the earliest signs of Alzheimer’s disease. New research may finally help to explain why, and it involves a simple protein and its mutation.

Amyloid precursor protein – or APP – has long been associated with Alzheimer’s, which causes between 60-80% of all dementia cases. Amyloid plaques, which are derived from APP, have been suspected to contribute to the death of nerve cells in the brains of people with Alzheimer’s, leading to memory loss. But a recent study uncovered a striking effect specifically on olfactory cells, which are the nerve cells that control sense of smell.

In this study, scientists genetically engineered mice to produce high levels of a mutated form of APP, and the results were striking. Specifically, mice containing the protein’s mutated form had four times as much olfactory nerve cell death than normal mice; furthermore, these olfactory cells died apart from the presence of the amyloid plaques associated with dementia. And when researchers blocked the production of high levels of the mutated APP, more olfactory nerve cells survived.

So what does this mean for the future of Alzheimer’s research? It could be a real step in learning how to stop the disease-related death of brain cells, and potentially reverse – or even prevent – the onset of dementia. Read more on the Alzheimer’s Association website.