Skin Biomarker May Lead to Fast Test for Alzheimer's

Researchers have identified a biomarker present in some types of skin cells that may allow for the development of a fast, noninvasive diagnostic test for Alzheimer's disease.

Results published over the last several years have indicated that the changes taking place in the brain of an individual afflicted with Alzheimer's disease are reflected by changes in the biochemical behavior of cells in other parts of the body.

Investigators at the Blanchette Rockefeller Neurosciences Institute (Rockville, MD, USA) looked for biochemical differences in fibroblasts taken from the skin of Alzheimer's patients, patients with other types of dementia, and from normal controls. They observed differences in the activity of ERK1 and ERK2 (extracellular signal-regulated kinases) in fibroblasts from Alzheimer's patients as compared to controls and other patients.

ERK1 and ERK2 belong to the mitogen-activated protein kinase (MAPK) family. MAPKs are serine/threonine-specific protein kinases that respond to extracellular stimuli (mitogens) and regulate various cellular activities, such as gene expression, mitosis, differentiation, and cell survival/apoptosis. The ERKs (also known as classical MAPKs) signaling pathway is preferentially activated in response to growth factors and regulates cell proliferation and cell differentiation. This MAPK signaling cascade has been evolutionarily well conserved from yeast to mammals.

A paper published in the August 18, 2006, online edition of the Proceedings of the [U.S.] National Academy of Sciences described how results obtained from the analysis of skin samples from the Coriell Cell Repository (Camden, NJ, USA) and for samples analyzed on gels with autopsy diagnostic confirmation enabled the investigators to establish an "Alzheimer's Index” that accurately distinguished fibroblasts of Alzheimer's patients from those of normal controls and of non-Alzheimer's dementias.

"The results demonstrate that when the Alzheimer's Index agrees with the clinical diagnosis of the presence of Alzheimer's, there is a high probability of accurate diagnosis,” said senior author Dr. Daniel L. Alkon, scientific director of the Blanchette Rockefeller Neurosciences Institute. "When it begins, Alzheimer's disease is often difficult to distinguish from other dementias or mild cognitive impairment. Potential treatments of Alzheimer's, however, are likely to have their greatest efficacy before the devastating and widespread impairment of brain function that inevitably develops after four or more years.”



Related Links:
Blanchette Rockefeller Neurosciences Institute
Coriell Cell Repository