Abnormal Salivary Total and Oligomeric Alpha-Synuclein in Parkinson's Disease

• Published in: PloS one 2016-03, Vol.11 (3), p.e0151156
• Main Authors: Vivacqua, Giorgio, Latorre, Anna, Suppa, Antonio, Nardi, Michela, Pietracupa, Sara, Mancinelli, Romina, Fabbrini, Giovanni, Colosimo, Carlo, Gaudio, Eugenio, Berardelli, Alfredo
• Format: Article
• Language: English
• Subjects: Adult; Age; Aged; Aged, 80 and over; alpha-Synuclein - analysis; alpha-Synuclein - metabolism; Biology and Life Sciences; Biomarkers; Biomarkers - analysis; Biomarkers - metabolism; Brain; Cognitive ability; Cohort Studies; Correlation; Dementia; Diagnosis; Drug dosages; Early Diagnosis; Enzyme-linked immunosorbent assay; Feasibility studies; Female; Fluids; Humans; Male; Medicine and Health Sciences; Mental depression; Middle Aged; Monomers; Movement disorders; Neurodegenerative diseases; Neurology; Neurotoxicity; Oligomers; Parkinson disease; Parkinson Disease - diagnosis; Parkinson Disease - metabolism; Parkinson's disease; Pathogenesis; Patients; Physical Sciences; Physiological aspects; Protein Aggregates; Proteins; Psychiatry; Research and Analysis Methods; Risk factors; Saliva; Saliva - chemistry; Saliva - metabolism; Solubility; Synuclein
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0151156

In Parkinson's disease (PD), alpha-synuclein (a-syn) can be detected in biological fluids including saliva. Although previous studies found reduced a-syn total (a-syntotal) concentration in saliva of PD patients, no studies have previously examined salivary a-syn oligomers (a-synolig) concentrations or assessed the correlation between salivary a-syntotal, a-synolig and clinical features in a large cohort of PD patients. Is well known that a-synolig exerts a crucial neurotoxic effect in PD. We collected salivary samples from 60 PD patients and 40 age- and sex-comparable healthy subjects. PD was diagnosed according to the United Kingdom Brain Bank Criteria. Samples of saliva were analyzed by specific anti-a-syn and anti-oligomeric a-syn ELISA kits. A complete clinical evaluation of each patient was performed using MDS-Unified Parkinson's Disease Rating Scale, Beck Depression Inventory, Montreal Cognitive Assessment and Frontal Assessment Battery. Salivary a-syntotal was lower, whereas a-synolig was higher in PD patients than healthy subjects. The a-synolig/a-syntotal ratio was also higher in patients than in healthy subjects. Salivary a-syntotal concentration negatively correlated with that of a-synolig and correlated with several patients' clinical features. In PD, decreased salivary concentration of a-syntotal may reflect the reduction of a-syn monomers (a-synmon), as well as the formation of insoluble intracellular inclusions and soluble oligomers. The combined detection of a-syntotal and a-synolig in the saliva might help the early diagnosis of PD.