Ana M. Novella Cámara

Combined dementia-risk biomarkers in Parkinson's disease: A prospective longitudinal study

Neuropsychological (mostly posterior-cortical) deficits, quantitative magnetic resonance imaging (MRI) atrophy patterns, and low cerebrospinal fluid (CSF) levels of amyloid-β have been separately related to worsening cognition in Parkinsons disease (PD). However, these biomarkers have not been longitudinally assessed in combination as PD-dementia predictors. In this prospective longitudinal study, 27 non-demented PD patients underwent CSF, neuropsychological and 3-T brain-MRI studies at baseline and were re-assessed 18 months later in terms of progression to dementia (primary outcome) and longitudinal neuropsychological and cortical thickness changes (secondary outcomes). At follow-up 11 patients (41%) had progressed to dementia. Lower CSF amyloid-β, worse verbal learning, semantic fluency and visuoperceptual scores, and thinner superior-frontal/anterior cingulate and precentral regions were significant baseline dementia predictors in binary logistic regressions as quantitative and/or dichotomised traits. All participants without baseline biomarker abnormalities remained non-demented whereas all with abnormalities in each biomarker type progressed to dementia, with intermediate risk for those showing abnormalities in a single to two biomarker types (p = 0.006). Both the dementia-outcome and low baseline CSF amyloid-β were prospectively associated with limbic and posterior-cortical neuropsychological decline and frontal, limbic and posterior-cortical thinning from baseline to follow-up. These findings suggest that the combination of CSF amyloid-β, neuropsychological and cortical thickness biomarkers might provide a basis for dementia-risk stratification and progression monitoring in 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 Alzheimers 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), Parkinsons 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.

Long-term response to continuous duodenal infusion of levodopa/ carbidopa gel in patients with advanced Parkinson disease: The Barcelona registry

INTRODUCTION Continuous infusion of levodopa/carbidopa intestinal gel (LCIG) is an effective treatment for patients with advanced Parkinson Disease (PD) that cannot be further improved by oral therapy. METHODS We conducted an observational, prospective, and multicenter study to collect, in a large sample of PD treated with LCIG, long-term information about the outcome and safety of the treatment. The assessments were performed before LCIG, 1, 3, 6 months after, and ever since, every 6 months. RESULTS We studied 72 patients with a mean observation time of 22 months and a maximum of 48 months. During follow-up 28 patients discontinued the treatment, especially for lack of efficacy or adverse events related to the drug. We obtained a significant improvement of motor and non-motor fluctuations, mean off time and some non-motor symptoms. A significant increase in the percentage of time with dyskinesias was found in patients having less than 50% of the day with dyskinesias before LCIG. However, patients having already many dyskinesias before LCIG experienced a significant decrease of the troublesome dyskinesias, meaning that outcomes might be different depending on specific clinical characteristics. Adverse effects were in general minor but one case of intestinal perforation and one of abdominal cellulite were observed. CONCLUSIONS We confirmed that LCIG is a very effective treatment option for advanced PD; however considering the findings that dyskinesia can increase and the potential for serious side effects, we suggest the necessity for development of guidelines that better define the profile of responders.

High cerebrospinal tau levels are associated with the rs242557 tau gene variant and low cerebrospinal β-amyloid in Parkinson disease

Cerebrospinal fluid (CSF) tau and phospho-tau levels have been associated with certain tau gene variants and low CSF amyloid-β (Aβ) levels in Alzheimer disease (AD), constituting potential biomarkers of molecular mechanisms underlying neurodegeneration. We aimed to assess whether such CSF-genetic endophenotypes are also present in Parkinson disease (PD). CSF tau, phospho-tau and Aβ levels were obtained from 38 PD patients (19 with dementia) using specific ELISA techniques. All cases were genotyped for a series of tau gene polymorphisms (rs1880753, rs1880756, rs1800547, rs1467967, rs242557, rs2471738 and rs7521). The A-allele rs242557 polymorphism was the only tau gene variant significantly associated with higher CSF tau and phospho-tau levels, under both dominant and dose-response model. This association depended on the presence of dementia, and was only observed in individuals with low (<500pg/mL) CSF Aβ levels. Such genetic-CSF endophenotypes are probably a reflection of the presence of AD-like molecular changes in part of PD patients in the setting of dementia.

Cross-Sectional and Longitudinal Cognitive Correlates of FDDNP PET and CSF Amyloid-β and Tau in Parkinson’s Disease1

Tau and amyloid-β (Aβ) aggregates have been suggested to play a role in the development of dementia in Parkinsons disease (PD). Positron emission tomography (PET) with [18F]FDDNP and the determination of cerebrospinal fluid (CSF) levels of these proteins constitute a means to visualize in vivo Aβ and tau brain accumulation. Information about longitudinal changes of these CSF and PET biomarkers in PD with regard to progression to dementia is lacking. We assessed the cross-sectional and longitudinal associations of CSF and PET biomarkers of tau and Aβ with PD-related cognitive dysfunction in 6 healthy-controls (HC), 16 patients with PD without dementia (PDND), and 8 PD with dementia (PDD). All subjects underwent comprehensive neuropsychological testing, [18F]FDDNP PET, and CSF Aβ-tau determination. After 18 months, the PDND group was re-assessed clinically and by neuropsychological, PET, and CSF determinations. Cross-sectionally, PDD had higher [18F]FDDNP binding in lateral temporal regions and lower levels of CSF Aβ levels compared to PDND, with a congruent correlation between the [18F]FDDNP binding and CSF Aβ levels. Longitudinally, higher baseline lateral temporal [18F]FDDNP binding was associated to longitudinal worsening in cognitive performances and progression to dementia among subjects classified as PDND at baseline, who additionally disclosed at follow-up an increase in lateral-temporal FDDNP binding, as well as a reduction in CSF Aβ and an increase in CSF tau levels. These results confirm the relevance of these CSF and PET biomarkers to PDD, being specifically the first to show [18F]FDDNP PET as a dementia risk biomarker in PD, along with longitudinal CSF and PET changes over time.

White matter hyperintensities, cerebrospinal amyloid-β and dementia in Parkinson's disease

Abstract White-matter hyperintensities (WMHs) have been related to small-vessel disease, but also to amyloid-β (Αβ) vascular deposition, particularly in parieto-occipital regions. Low cerebrospinal fluid (CSF) Aβ [1-42] levels (biomarker of parenchymal and/or vascular Aβ deposition) and WMHs have been associated with Parkinsons disease (PD) and related dementia (PDD), separately but not in combination. We studied 50 subjects: 38 PD patients (19 non-demented [PDND]+19 PDD) and 12 healthy-controls. Baseline regional WMHs from FLAIR MRI-sequences were dichotomized into none-to-mild vs. moderate-to-severe by an expert radiologist blind to clinical and CSF data using an adaption of the Age-Related White Matter Changes scale. Baseline CSF α-synuclein, τ and Aβ [1-42] levels were determined with ELISA techniques. Progression to dementia in PDND patients was clinically evaluated at 18months. For analyses purposes patients were considered altogether (PDND+PDD) and separately (PDND vs. PDD). At baseline, moderate-to-severe parieto-occipital WMHs were significantly more frequent in PDD than in PDND ( p =0.049) and controls ( p =0.029), without significant differences in other regions. In regression models CSF Aβ was significantly associated in the entire PD cohort with moderate-to-severe parieto-occipital WMHs independently of age, vascular risk factors, APOE-4 and dementia. There were no associations with CSF α-synuclein and τ. Progression to dementia at 18months was more frequent in patients with moderate-to-severe parieto-occipital WMHs and low CSF Aβ vs. those with none-to-mild parieto-occipital WMHs and normal CSF Aβ ( p =0.007). It remains to be seen whether the relationship between CSF Aβ and WMHs in PD and their association with PD-dementia is a reflection of not only parenchymal, but also vascular Αβ deposition.

Cerebrospinal fluid levels of coenzyme Q10 are reduced in multiple system atrophy

INTRODUCTION The finding of mutations of the COQ2 gene and reduced coenzyme Q10 levels in the cerebellum in multiple system atrophy (MSA) suggest that coenzyme Q10 is relevant to MSA pathophysiology. Two recent studies have reported reduced coenzyme Q10 levels in plasma and serum (respectively) of MSA patients compared to Parkinsons disease and/or control subjects, but with largely overlapping values, limited comparison with other parkinsonisms, or dependence on cholesterol levels. We hypothesized that cerebrospinal fluid (CSF) is reliable to assess reductions in coenzyme Q10 as a candidate biomarker of MSA. METHODS In this preliminary cross-sectional study we assessed CSF coenzyme Q10 levels in 20 patients with MSA from the multicenter Catalan MSA Registry and of 15 PD patients, 10 patients with progressive supranuclear palsy (PSP), and 15 control subjects from the Movement Disorders Unit Biosample Collection of Hospital Clinic de Barcelona. A specific ELISA kit was used to determine CSF coenzyme Q10 levels. CSF coenzyme Q10 levels were compared in MSA vs. the other groups globally, pair-wise, and by binary logistic regression models adjusted for age, sex, disease severity, disease duration, and dopaminergic treatment. RESULTS CSF coenzyme Q10 levels were significantly lower in MSA than in other groups in global and pair-wise comparisons, as well as in multivariate regression models. Receiver operating characteristic curve analyses yielded significant areas under the curve for MSA vs. PD, PSP and controls. CONCLUSIONS These findings support coenzyme Q10 relevance in MSA. Low CSF coenzyme Q10 levels deserve further consideration as a biomarker of MSA.

Cross-sectional and longitudinal associations of motor fluctuations and non-motor predominance with cerebrospinal τ and Aβ as well as dementia-risk in Parkinson's disease

Experimental, neuropathological and cerebrospinal fluid (CSF) studies support τ and amyloid-β (Aβ) relevance in Parkinsons disease (PD) related dementia. Lesser motor fluctuations (MFs) and non-motor features have also been related to PD-dementia. Yet, little is known about the association of MFs and non-motor symptoms with CSF τ and Aβ in PD. We hypothesized that lesser MFs and non-motor predominance are related to these CSF markers and dementia-risk in PD. We studied 58 PD patients (dementia at baseline, n=21; dementia at 18-months, n=35) in whom CSF Aβ and τ had been determined with ELISA techniques. MFs and a number of non-motor symptoms (apathy, anxiety, irritability, depression, visual hallucinations, spatial disorientation, memory complaints) over disease course were dichotomized as absent-mild vs. moderate-severe by retrospective clinical chart review blind to CSF findings. Non-motor predominance was defined as ≥3 non-motor symptoms (after the cohort-median of non-motor symptoms per patient) with ≥2 being moderate-severe and ≥1 having been present from onset, with all these being more disabling overall than motor features. Cross-sectionally, CSF biomarkers were non-parametrically compared according to dichotomized MFs and non-motor predominance. Longitudinally, dementia was the outcome (dependent variable), CSF markers, MFs and non-motor predominance were the predictors (independent variables), and potential modifiers as age, sex, and memory complaints were the covariates in binary regression models. Absent-mild MFs were associated with higher CSF τ markers and shorter time-to-dementia, while non-motor predominance and decreasing CSF Aβ independently increased longitudinal dementia-risk. In summary, absent-mild MFs, non-motor predominance and CSF τ and Aβ might define endophenotypes related to the timing or risk of dementia in PD.

Simultaneous low-frequency deep brain stimulation of the substantia nigra pars reticulata and high-frequency stimulation of the subthalamic nucleus to treat levodopa unresponsive freezing of gait in Parkinson's disease: A pilot study

INTRODUCTION Experimental studies suggest that low-frequency (LF) (63 Hz) deep brain stimulation (DBS) of the substantia nigra pars reticulata (SNr) could be useful to regulate gait disorders refractory to medical treatment in Parkinsons disease (PD). The SNr neurons could act as high-frequency (HF) pacemakers within locomotor control systems. Currently, no specific therapies can treat gait disorders in PD with insufficient response to dopaminergic treatment. OBJECTIVE To investigate whether LF-SNr-DBS combined with standard HF stimulation of the subthalamic nucleus (STN) is clinically relevant in improving gait disorders that no longer respond to levodopa in PD patients, compared with HF-STN or LF-SNr stimulation alone. METHODS Patients received LF-SNr or HF-STN stimulation alone or combined (COMB) stimulation of both nuclei (crossover design). The nucleus to be stimulated was randomly assigned and clinical evaluations performed by a blinded examiner after three months follow-up for each. Clinical assessment included the Freezing of Gait questionnaire, Tinetti Balance and Walking Assessing tool, and Unified Parkinsons Disease Rating. RESULTS We included six patients (mean age 59.1 years, disease duration 16.1 years). All patients suffered motor fluctuations and dyskinesias. The best results were obtained with COMB in four patients (who preferred and remained with COMB over 3 years of follow-up) and with HF-STN in two patients. SNr stimulation alone did not produce better results than COMB or STN in any patient. CONCLUSION COMB and HF-STN stimulation improved PD-associated gait disorders in this preliminary case series, sustained over time. Further multicenter investigations are required to better explore this therapeutic option.

Citizenship without certainties

La idea de ciudadania se ha basado en la busqueda de algo en comun, algo que se impone y pauta la existencia personal y social. Este modelo pierde vigencia con la progresiva disolucion de las certezas que dictaban los canones de verdad y bondad. La progresiva desaparicion de las seguridades es una liberacion que nos obliga a buscar caminos para idear nuevas formas de vida digna. Reconocer la diferencia y la voluntad de dialogo son dinamismos oportunos en un mundo sin seguridades. Dinamismos que pueden manifestarse de modo ejemplar en el trabajo cientifico y en la politica deliberativa. El articulo pone en cuestion este argumento para mostrar como las practicas escolares similares —proyectos de trabajo y asambleas de clase —ensenan como vivir sin certezas. Y lo logran cuando el proceso de tutoria refuerza los valores inherentes a este tipo de practicas. Los autores concluyen afirmando que la ausencia de certezas no significa la falta de compromiso, esperanza y solidaridad.