New research suggests that a simple skin test might be developed in the fairly near future that could help diagnose degenerative diseases such as Alzheimer’s at a much earlier stage.
“Early diagnosis is essential and it may be that the skin can provide us with the relevant clues to achieve this…,” says Dr Conal Perrett, a leading dermatologist London based with his own practice in the Harley Street district. Here he reviews the latest evidence and looks at the prospects for a future skin test that could spot the earliest signs of dementia.
What is Alzheimer’s disease?
Alzheimer’s disease is a degenerative disease of the brain that leads to dementia. Like other forms of dementia, it is highly distressing both for those affected and for their families and friends.
One of the problems facing doctors who try to treat it is delay between changes in the brain and central nervous system and the appearance of symptoms.
The first signs of forgetfulness, memory loss and changes in behaviour that are typical of Alzheimer’s are often only recognised when the damage to the nerve cells and brain tissue is quite advanced.
Detecting changes in brain tissue is impossible and Alzheimer’s is diagnosed on the basis of the symptoms that develop and that worsen over time. Diagnosing the disease more accurately and at a much earlier stage might help to delay its progression, giving people a better quality of life for longer.
The latest research on skin and Alzheimer’s
So far, researchers have tried looking for brain biomarkers in the blood to predict which patients might develop Alzheimer’s, but this has proved difficult.
A group in Mexico, at the University of San Luis Potosi, took a different approach. They looked back at the embryo for clues to direct their studies.
Studies of how the tissues of the embryo develop have shown that the brain and the skin are generated from the same clump of early cells. They share a common origin.
Dr Ildefonso Rodriguez-Leyva, who leads the group, thinks that the skin might show some of the same early changes as the brain in Alzheimer’s, other forms of dementia and Parkinson’s disease.
“The skin is a much more accessible tissue than the brain. If a test was possible, dermatologists could play an important role in taking skin biopsy samples for analysis,” adds Dr Perrett.
Looking for protein deposits in the skin
The researchers are convinced they are onto something because the protein deposits that are found in patients with Parkinson’s disease have also been observed in skin samples taken after their death. But no studies until now have looked for changes within the skin of living patients.
Deciding that the evidence was strong enough to justify a small clinical trial, the Mexican group collected together a people with either Parkinson’s disease, dementia or Alzheimer’s disease. Just a dozen or so of each, plus a dozen healthy people with no signs of brain disease.
A small skin sample was obtained from behind their ear and was examined using powerful microscopes and chemical tests.
Brain tangling proteins discovered in the skin
The results have generated a great deal of excitement among neurologists and dermatologists. They showed that two key proteins were present in much greater quantities in the skin of patients with either Parkinson’s or Alzheimer’s compared to those with other forms of dementia, or compared to the healthy people used as controls.
The proteins – tau and alpha synuclein – are known to clump up in the brain and major nerves, causing memory loss and other problems.
“The link between the skin and the brain definitely seems to be worth exploring further,” comments Dr Perrett, Medical Director and lead dermatologist at The Devonshire Clinic. “Analysis of the skin can often provide important insights into diseases affecting other part so of the body as demonstrated by this research into Alzheimer’s disease and Parkinson’s disease,” he adds.
Looking to the future
Although the results released so far appear to be very promising, a lot more still needs to be done before a test could be used in clinics. Larger clinical trials over a longer period of time are needed.
Hopefully, if things do go well, skin tests might be able to highlight early changes that will predict which people are likely to go on to develop brain disease.
Find out more about the medical dermatology services offered by The Devonshire Clinic.