Skin biomarkers for neurodegenerative disease: a future perspective

In the search for potential histological markers, the acquisition of any nervous tissue is still currently a complex and hazardous intervention in humans. [...]other tissues have been evaluated as possible surrogates, including those of the salivary glands, olfactory epithelium, heart and digestive tract(8,9). Studies have shown that genes expressed in signaling pathways operating in age-associated neurodegenerative disease, such as Huntington’s disease, dentatorubral-pallidoluysian atrophy, amyotrophic lateral sclerosis and PD, are expressed inhormonally aged human sebocytes(10,12). [...]cutaneous tissue is a promising source in the search for biological markers of neurodegenerative conditions. The discrepancy between the results of the autopsy-based study and the in vivo study may be explained by differences in the sites of the obtained samples, the size and number of examined sections, the type of antibodies used for α-synuclein (phosphorylated/non-phosphorylated) and the histological processing (fresh frozen or paraffin-embedded tissue). [...]α-synuclein aggregates have also been recently demonstrated in peripheral nerve terminals of the epidermis and skin appendages of PD patients(16). A major drawback is that worldwide, most health systems do not have the capacity to offer these tests in clinical practice. [...]skin biopsies may represent an alternative to support the diagnosis of PD and Alzheimer’s disease, the two most common neurodegenerative diseases.