WHOPPA Enables Parallel Assessment of Leucine-Rich Repeat Kinase 2 and Glucocerebrosidase Enzymatic Activity in Parkinson's Disease Monocytes.

Both leucine-rich repeat kinase 2 (LRRK2) and glucocerebrosidase (GCase) are promising targets for the treatment of Parkinson's disease (PD). Evidence suggests that both proteins are involved in biological pathways involving the lysosome. However, studies to date have largely investigated the enzymes in isolation and any relationship between LRRK2 and GCase remains unclear. Both enzymes are highly expressed in peripheral blood monocytes and have been implicated in immune function and inflammation. To facilitate the standardized measurement of these readouts in large cohorts of samples collected from persons with PD across the globe, we developed and optimized a sample collection and processing protocol with parallel flow cytometry assays. Assay parameters were first optimized using healthy control peripheral blood mononuclear cells (PBMCs), and then LRRK2 and GCase activities were measured in immune cells from persons with idiopathic PD (iPD). We tested the ability of this protocol to deliver similar results across institutes across the globe, and named this protocol the Wallings-Hughes Optimized Protocol for PBMC Assessment (WHOPPA). In the application of this protocol, we found increased LRRK2 levels and stimulation-dependent enzymatic activity, and decreased GBA index in classical iPD monocytes, as well as increased cytokine release in PD PBMCs. WHOPPA also demonstrated a strong positive correlation between LRRK2 levels, pRab10 and HLA-DR in classical monocytes from subjects with iPD. These data support a role for the global use of WHOPPA and expression levels of these two PD-associated proteins in immune responses, and provide a robust assay to determine if LRRK2 and GCase activities in monocytes have potential utility as reliable and reproducible biomarkers of disease in larger cohorts of subjects with PD.

Development and assessment of sensitive immuno-PCR assays for the quantification of cerebrospinal fluid three- and four-repeat tau isoforms in tauopathies.

Characteristic tau isoform composition of the insoluble fibrillar tau inclusions define tauopathies, including Alzheimer's disease (AD), progressive supranuclear palsy (PSP) and frontotemporal dementia with parkinsonism linked to chromosome 17/frontotemporal lobar degeneration-tau (FTDP-17/FTLD-tau). Exon 10 splicing mutations in the tau gene, MAPT, in familial FTDP-17 cause elevation of tau isoforms with four microtubule-binding repeat domains (4R-tau) compared to those with three repeats (3R-tau). On the basis of two well-characterised monoclonal antibodies against 3R- and 4R-tau, we developed novel, sensitive immuno-PCR assays for measuring the trace amounts of these isoforms in CSF. This was with the aim of assessing if CSF tau isoform changes reflect the pathological changes in tau isoform homeostasis in the degenerative brain and if these would be relevant for differential clinical diagnosis. Initial analysis of clinical CSF samples of PSP (n = 46), corticobasal syndrome (CBS; n = 22), AD (n = 11), Parkinson's disease with dementia (PDD; n = 16) and 35 controls revealed selective decreases of immunoreactive 4R-tau in CSF of PSP and AD patients compared with controls, and lower 4R-tau levels in AD compared with PDD. These decreases could be related to the disease-specific conformational masking of the RD4-binding epitope because of abnormal folding and/or aggregation of the 4R-tau isoforms in tauopathies or increased sequestration of the 4R-tau isoforms in brain tau pathology.

Assessment of cortical degeneration in patients with Parkinson's disease by voxel-based morphometry, cortical folding, and cortical thickness.

Noninvasive brain imaging methods provide useful information on cerebral involution and degenerative processes. Here we assessed cortical degeneration in 20 nondemented patients with Parkinson's disease (PD) and 20 healthy controls using three quantitative neuroanatomical approaches: voxel-based morphometry (VBM), cortical folding (BrainVisa), and cortical thickness (FreeSurfer). We examined the relationship between global and regional gray matter (GM) volumes, sulcal indices, and thickness measures derived from the previous methods as well as their association with cognitive performance, age, severity of motor symptoms, and disease stage. VBM analyses showed GM volume reductions in the left temporal gyrus in patients compared with controls. Cortical folding measures revealed significant decreases in the left frontal and right collateral sulci in patients. Finally, analysis of cortical thickness showed widespread cortical thinning in right lateral occipital, parietal and left temporal, frontal, and premotor regions. We found that, in patients, all global anatomical measures correlated with age, while GM volume and cortical thickness significantly correlated with disease stage. In controls, a significant association was found between global GM volume and cortical folding with age. Overall these results suggest that the three different methods provide complementary and related information on neurodegenerative changes occurring in PD, however, surface-based measures of cortical folding and especially cortical thickness seem to be more sensitive than VBM to identify regional GM changes associated to PD.

Prospective comparative study on cost-effectiveness of subthalamic stimulation and best medical treatment in advanced Parkinson's disease.

This is an open, prospective, longitudinal study designed to compare two cohorts of patients with advanced Parkinson's disease during 1 year, one undergoing bilateral subthalamic stimulation (STN-DBS) and the other receiving the best medical treatment (BMT), with respect to the clinical effects observed and the medical expenses produced. Assessments were done by using clinical measures and a generic health related quality of life scale. A questionnaire was used to collect direct healthcare resources. As a measure of cost-effectiveness, we calculated life years gained adjusted by health-related quality of life (QALY) and the incremental cost-effectiveness ratio (ICER). Clinical and demographic variables of both groups were comparable at baseline. Total UPDRS scores improved from 50.5 +/- 3.6 to 28.5 +/- 3.8 in STN-DBS patients and worsened from 44.3 +/- 3.3 to 54.2 +/- 4 in the control group. Pharmacological costs in the operated patients were 3,799 +/- 940 euro, while in the BMT group the costs were 13,208 +/- 4,966 euro. Other medical costs were 1,280 +/- 720 euro in the STN-DBS group and 4,017 +/- 2,962 euro in BMT patients. Nondirect medical costs were 4,079 +/- 1,289 in operated patients and 2,787 +/- 1,209 euro in the BMT group. Mean QALYs were 0.7611 +/- 0.03 in STN-DBS and 0.5401 +/- 0.06 in BMT patients. In STN-DBS patients, the ICER needed to obtain an improvement of one point in the total UPDRS score was of 239.8 euro and the ICER/QALY was of 34,389 euro. Cost-effectiveness parameters were mostly related to the degree of clinical improvement and the reduction of pharmacological costs after STN-DBS. An ICER of 34,389 euro/QALY is within appropriate limits to consider subthalamic stimulation as an efficient therapy.