Glucocerebrosidase Activity is Reduced in Cryopreserved Parkinson's Disease Patient Monocytes and Inversely Correlates with Motor Severity.

BACKGROUND: Reduced activity of lysosomal glucocerebrosidase is found in brain tissue from Parkinson's disease patients. Glucocerebrosidase is also highly expressed in peripheral blood monocytes where its activity is decreased in Parkinson's disease patients, even in the absence of GBA mutation. OBJECTIVE: To measure glucocerebrosidase activity in cryopreserved peripheral blood monocytes from 30 Parkinson's disease patients and 30 matched controls and identify any clinical correlation with disease severity. METHODS: Flow cytometry was used to measure lysosomal glucocerebrosidase activity in total, classical, intermediate, and non-classical monocytes. All participants underwent neurological examination and motor severity was assessed by the Movement Disorders Society Unified Parkinson's Disease Rating Scale. RESULTS: Glucocerebrosidase activity was significantly reduced in the total and classical monocyte populations from the Parkinson's disease patients compared to controls. GCase activity in classical monocytes was inversely correlated to motor symptom severity. CONCLUSION: Significant differences in monocyte glucocerebrosidase activity can be detected in Parkinson's disease patients using cryopreserved mononuclear cells and monocyte GCase activity correlated with motor features of disease. Being able to use cryopreserved cells will facilitate the larger multi-site trials needed to validate monocyte GCase activity as a Parkinson's disease biomarker.

Hyperechogenicity of the Substantia Nigra in Parkinson's Disease: Insights from Two Brothers with Markedly Different Disease Durations.

We present clinical features and substantia nigra morphology for two brothers with Parkinson's disease (PD) aged 60 and 59 years. The brothers were diagnosed at 41 and 50 years of age, respectively. Both patients exhibited an abnormally large area of substantia nigra echogenicity bilaterally when viewed with transcranial ultrasound. The abnormality was similar in both brothers despite one having a much longer disease duration than the other. These findings further highlight that transcranial ultrasound is not associated with severity of clinical symptoms, but it might assist in the diagnosis of PD provided that it is combined with other variables known to precede PD.