Evaluation of salivary heme oxygenase-1 as a potential biomarker of early Parkinson's disease

Background and HypothesisTo date, there are no chemical analytes, including biochemical indices of oxidative stress, metabolites of -synuclein protein, and differential protein expression patterns on proteomic profiling, for use in clinics as a diagnostic biomarker of idiopathic PD. ObjectivesHeme oxygenase-1 has been implicated in the pathogenesis of PD. The objective of this study is to ascertain whether salivary heme oxygenase-1 may serve as a biomarker for early idiopathic PD. MethodsFifty-eight PD patients and 59 non-neurological disease controls were recruited. Levels of heme oxygenase-1 expression were assayed using enzyme-linked immunosorbent assay and western blot analysis of whole, unstimulated saliva. Analyses were adjusted by sex, l-dopa exposure, and relevant comorbidities. ResultsWe documented: (1) the presence of 32-kDa heme oxygenase-1 protein in human saliva; (2) significantly higher mean heme oxygenase-1 protein concentrations in saliva of PD patients relative to control values; (3) no variability in salivary heme oxygenase-1 levels with sex, age, l-dopa equivalence, or comorbidities; and (4) significantly higher mean salivary heme oxygenase-1 concentrations in patients with H & Y stage 1 PD (early) than control subjects and stage 2 and stage 3 PD patients. The area under the receiver operating characteristic curve that separated controls from PD H & Y stage 1 was 76% (95% confidence interval: 63-90). ConclusionsSalivary heme oxygenase-1 concentrations may provide a useful, noninvasive, and relatively inexpensive biomarker of early idiopathic PD. (c) 2018 International Parkinson and Movement Disorder Society