March 12, 2015
Mexican researchers report that changes in the skin may offer early clues to an Alzheimer’s diagnosis. The findings could one day lead to a simple skin test to diagnose Alzheimer’s at a stage when treatments may be most effective.
Currently, Alzheimer’s can be diagnosed definitively only by looking for telltale signs of the disease in brain tissue after death. But the new findings suggest that skin changes may offer a simpler way to diagnose Alzheimer’s. The researchers also found unique skin changes in those with Parkinson’s disease, another degenerative nervous system ailment that can cause dementia and be difficult to diagnose early on.
“Until now, pathological confirmation was not possible without a brain biopsy, so these diseases often go unrecognized until after the disease has progressed,” said study author Dr. Ildefonso Rodriguez-Leyva at Central Hospital at the University of San Luis Potosi in Mexico. “This new test offers a potential biomarker that may allow doctors to identify and diagnose these diseases earlier on.”
The findings will be presented at the American Academy of Neurology’s 67th Annual Meeting in Washington, D.C., in April.
In early embryonic development, both skin and brain tissue arise out of the same kind of tissue. “We hypothesized that since skin has the same origin as brain tissue while in the embryo that they might also show the same abnormal proteins,” Dr. Rodriquez-Leyva said.
For the study, the researchers took skin biopsies from behind the ear of 20 people with Alzheimer’s disease, 16 with Parkinson’s disease and 17 with dementia caused by other conditions. They compared them to 12 healthy people of similar ages.
They found that people with Alzheimer’s or Parkinson’s had high levels in the skin of the tau protein, an abnormal protein that builds up in the brains of those with both diseases. Levels were seven times higher, on average, than the levels found in those with other forms of dementia or healthy controls. People with Parkinson’s disease also had high levels of another protein called alpha-synuclein.
“This skin test opens the possibility to see abnormal proteins in the skin before central nervous system symptoms — cognitive or motor deficits — appear,” Dr. Rodriguez-Leyva said. “More research is needed to confirm these results, but the findings are exciting because we could potentially begin to use skin biopsies from living patients to study and learn more about these diseases. This also means tissue will be much more readily available for scientists to study.”
Scientists have been looking for better tests to diagnose Alzheimer’s early, before damage to the brain becomes extensive. Many experts believe that drugs to stem the disease may be more effective at these early stages. Skin markers could also be used to test whether new drugs are effective in reducing progression of the disease.
But so far, tests for early diagnosis are in the experimental stage. In addition to this skin test, researchers are also exploring unique markers in the blood and spinal fluid, as well as changes in the sense of smell and other methods.
Better tests to diagnose and treat Alzheimer’s are urgently needed. Current therapies for Alzheimer’s may ease symptoms for a time but do little to stop the downward spiral of disease.
Source: American Academy of Neurology, 67th Annual Meeting in Washington, D.C., April 18, 2015.