The Diagnostic Value Of Minor Salivary Gland Biopsy In Clinically Diagnosed Patients With Parkinson’s Disease(H-Y Stage 1–2): Comparison With DAT PET Scans

Objective: To investigate the predictive value of minor salivary gland biopsy for the dopamine transporter positron emission tomography(DAT-PET) scans in clinically diagnosed early stage Parkinson’s disease(PD) patients, and to provide more evidence for minor salivary gland biopsy as a pathological diagnostic biomarker for PD and increase the accuracy of diagnosis. Methods: Thirteen patients with early stage PD and 13 age-matched controls were recruited from September 2013 to February 2015. Hoehn and Yahr stage(H-Y stage) and Unified Parkinson’s disease Rating Scale Part III were employed to evaluate their severity of the disease. All minor salivary gland specimens were obtained according to standard procedures by the same oral surgeon who was blinded to the diagnosis of the subjects. Immunohistochemical staining for Lewy-type alpha-synucleinopathy using antibody against alpha-synuclein or phosphorylated-α-synuclein was performed in the tissue. All the samples with positive immunoreactivity were counterstained with hematoxylin to highlight the normal morphology of the minor salivary glands. All the subjects underwent 11C-methyl-N-2β-carbomethoxy-3β-(4-fluorophenyl) tropane(11C-CFT) DAT-PET scan to investigate if there was consistency between the pathological result and PET scan. Results: Abnormal accumulation of α-syn was found around the gland cells in 9 of the 13 patients with PD, but in none of the control subjects. The α-syn inclusions were located in the periacinar space. No phosphorylated-α-synuclein positive structures had been found both in PD and controls. The 11C-CFT uptake in the caudate, anterior and posterior putamen was reduced at different levels in 12 PD patients including all the subjects in α-syn inclusions positive group, but decreased in only one control. The sensitivity, specificity, positive predictive value and negative predictive value of our biopsy results were 75%, 100%, 100% and 25% respectively when adapted to the DAT-PET imagine results. Conclusions: Our results provided more evidence that peripheral nervous system(PNS) has been affected by Lewy pathology(LP) in the early stages of PD. The α-syn inclusions were located in the periacinar space. And there was a consistency between the pathological result of minor salivary gland biopsy and DAT-PET scan. It has the potential to be a useful pathologically diagnostic biomarker for PD which needs more cases to confirm it is suggested that combination of minor salivary gland and DAT PET scan would increase the accuracy of early diagnosis of idiopathic PD.