A PROJECT to develop a test for the early stages of Alzheimer’s disease
is to be launched at the University of Sussex later this year. As a first
step, researchers will collect samples of the lining of the nose from people
suspected of having Alzheimer’s. Recent research carried out in the US suggests
that certain nasal tissue – the olfactory epithelium – shows distinctive
signs when people have the disease (New Scientist, Science, 11 March 1989).
When a person develops Alzheimer’s disease, nerves in the central nervous
system degenerate, resulting in distinctive features in the brain known
as plaques and tangles. But research into the treatment of the disease has
been paralysed by the lack of a diagnostic test: the cells of the central
nervous system are inaccessible.
At present, changes due to Alzheimer’s can be detected only by a brain
autopsy once the person is dead. In living patients, Alzheimer’s is diagnosed
by assessing the level of dementia, and by a brain scan, procedures that
may not be accurate.
Last year, however, Barbara Talamo and her colleagues at a number of
institutes, including Tufts Medical School and the New England Medical Center,
both in Boston, Massachusetts, made the discovery that Alzheimer’s disease
has a noticeable effect on the neurons in nasal tissue. It changes their
shape, their distribution, and the relative abundance of proteins they contain.
The researchers suggested that it would be possible to remove tissue from
a patient easily, under a general or even a local anaesthetic.
Lynne Mayne and her colleagues at Sussex University’s Trafford Centre
for Medical Research are starting a community study on a much larger scale
than the research programme in the US: they expect to study several tens
of patients a year, rather than the nine of the American study. They will
take a sample of nasal tissue from any Alzheimer’s patient who is undergoing
surgery, for any reason.
The researchers are also asking patients or their relatives to allow
them to take a sample of nasal tissue within hours of a patient’s death.
Speed is important because nerve cells degenerate very quickly. GPs will
be asked to take a nasal sample from any patient with Alzheimer’s who dies.
Mayne and her colleagues intend to compare the nasal tissue with brain
tissue, and with similar samples taken from healthy people. They want to
find out whether people with Alzheimer’s can be distinguished from those
with other forms of dementia by their nasal tissue alone.
The sensory neurons high up in the nose are unique among nerve cells
because they regenerate throughout adult life. They are also the only cells
of the central nervous system that can be sampled during life.
If a test can be developed, it will be important because current methods
of diagnosing Alzheimer’s disease are not accurate enough to assess the
potential of possible drugs. Another drawback is that it is impossible to
diagnose the disease until it is well advanced, when damage may be too extensive
for treatment by potential drugs.
According to Mayne, people coming to their doctors for the first time
with symptoms usually have problems with coordination. By then, a large
number of neurons have been lost. ‘The value of a diagnostic test,’ says
Mayne, ‘is that it could pick up the disease before the neurons have been
Mayne and Ruth Maxwell at the Trafford Centre hope to grow cells of
the central nervous system from healthy people and people with Alzheimer’s
in culture. Under controlled in vitro surroundings, they then intend to
subject the cells to a battery of environmental influences – such as aluminium
in water – which have been linked with the genesis of Alzheimer’s disease.
They hope that this will allow them to examine the way the neurons degenerate
Most researchers agree that nasal tissue could yield more information
about Alzheimer’s disease. But some believe that it is not the best practical
test in the pipeline. Gordon Wilcock, of the University of Bristol, a founder
of the Alzheimer’s Disease Society, says ‘I think patients will be much
happier to have their skin biopsied than their noses,’ says Wilcock. ‘I
have a feeling that the epithelial story is very interesting and may be
a useful tool for research, but it’s less likely to have major practical