Manel Fernández

IDIBAPS August Pi i Sunyer Biomedical Research Institute, Barcino, Catalonia, Spain

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Publications (10)32.64 Total impact

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    ABSTRACT: High-oligomeric and low-total-α-synuclein cerebrospinal fluid (CSF) levels have been found in Parkinson's disease (PD), but with inconsistent or limited data, particularly on their clinical and structural correlates in earliest (premotor) or latest (dementia) PD stages. We determined CSF oligomeric- and total-α-synuclein in 77 subjects: 23 with idiopathic REM-sleep behaviour disorder (iRBD, a condition likely to include a remarkable proportion of subjects in the premotor stage of PD) and 41 with PD [21 non-demented (PDND) + 20 demented (PDD)], intended to reflect the premotor-motor-dementia PD continuum, along with 13 healthy controls. The study protocol also included the Unified PD Rating Scale motor-section (UPDRS-III), mini mental state examination (MMSE), neuropsychological cognitive testing, 3T brain MRI for cortical-thickness analyses, CSF τ and CSF Aβ. CSF oligomeric-α-synuclein was higher in PDND than iRBD and in PDD than iRBD and controls, and correlated with UPDRS-III, MMSE, semantic fluency and visuo-perceptive scores across the proposed premotor-motor-dementia PD continuum (iRBD + PDND + PDD). CSF total-α-synuclein positively correlated with age, CSF Aβ, and, particularly, CSF τ, tending towards lower levels in PD (but not iRBD) vs. controls only when controlling for CSF τ. Low CSF total-α-synuclein was associated with dysfunction in phonetic-fluency (a frontal-lobe function) in PD and with frontal cortical thinning in iRBD and PDND independently of CSF τ. Conversely, the associations of high (instead of low) CSF total-α-synuclein with posterior-cortical neuropsychological deficits in PD and with posterior cortical thinning in PDD were driven by high CSF τ. These findings suggest that CSF oligomeric- and total-α-synuclein have different clinical, neuropsychological and MRI correlates across the proposed premotor-motor-dementia PD continuum. CSF total-α-synuclein correlations with CSF τ and Aβ support the hypothesis of an interaction among these proteins in PD, with CSF τ probably influencing the presence of high (instead of low) CSF total-α-synuclein and its correlates mostly in the setting of PD-related dementia.
    Journal of neurology. 11/2014;
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    ABSTRACT: Blood-cell-free circulating micro-RNAs (miRNAs) have been proposed as potential accessible biomarkers for neurodegenerative diseases such as Parkinson's disease (PD). Here we analyzed the serum levels of 377 miRNAs in a discovery set of 10 idiopathic Parkinson's disease (IPD) patients, 10 PD patients carriers of the LRRK2 G2019S mutation (LRRK2 PD), and 10 controls by using real-time quantitative PCR-based TaqMan MicroRNA arrays. We detected candidate differentially expressed miRNAs, which were further tested in a first validation set consisting of 20 IPD, 20 LRRK2 PD, and 20 control samples. We found four statistically significant miRNAs that were downregulated in either LRRK2 or IPD (miR-29a, miR-29c, miR-19a, and miR-19b). Subsequently, we validated these findings in a third set of samples consisting of 65 IPD and 65 controls and confirmed the association of downregulated levels of miR-29c, miR-29a, and miR-19b in IPD. Differentially expressed miRNAs are predicted to target genes belonging to pathways related to ECM–receptor interaction, focal adhesion, MAPK, Wnt, mTOR, adipocytokine, and neuron projection. Results from our exploratory study indicate that downregulated levels of specific circulating serum miRNAs are associated with PD and suggest their potential use as noninvasive biomarkers for PD. Future studies should further confirm the association of these miRNAs with PD. © 2014 Wiley Periodicals, Inc.
    Journal of Neuroscience Research 03/2014; · 2.97 Impact Factor
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    Parkinsonism & Related Disorders 11/2013; 19(11):1071-2. · 3.27 Impact Factor
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    ABSTRACT: 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 Parkinson's 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.
    Parkinsonism & Related Disorders 05/2013; · 3.27 Impact Factor
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    ABSTRACT: Alzheimer's disease (AD) is the most common neurodegenerative dementia. Approximately 10% of cases present at an age of onset before 65 years old, which in turn can be monogenic familial AD (FAD) or sporadic early-onset AD (sEOAD). Mutations in PSEN1, PSEN2, and APP genes have been linked with FAD. The aim of our study is to describe the brain whole-genome RNA expression profile of the posterior cingulate area in sEOAD and FAD caused by PSEN1 mutations (FAD-PSEN1). Fourteen patients (7 sEOAD and 7 FAD-PSEN1) and 7 neurologically healthy control subjects were selected and whole-genome expression was measured using Affymetrix Human Gene 1.1 microarrays. We identified statistically significant expression changes in sEOAD and FAD-PSEN1 brains with respect to control subjects (3183 and 3350 differentially expressed genes [DEG] respectively, false discovery rate-corrected p < 0.05). Of them, 1916 DEG were common between the 2 comparisons. We did not identify DEG between sEOAD and FAD-PSEN1. Microarray data were validated through real-time quantitative polymerase chain reaction. In silico analysis of DEG revealed an alteration in biological pathways related to intracellular signaling pathways (particularly calcium signaling), neuroactive ligand-receptor interactions, axon guidance, and long-term potentiation in both groups of patients. In conclusion, the altered biological final pathways in sEOAD and FAD-PSEN1 are mainly related with cell signaling cascades, synaptic plasticity, and learning and memory processes. We hypothesize that these 2 groups of early-onset AD with distinct etiologies and likely different could present a neurodegenerative process with potential different pathways that might converge in a common and similar final stage of the disease.
    Neurobiology of aging 01/2013; · 5.94 Impact Factor
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    ABSTRACT: Mutations in the leucine-rich repeat kinase 2 (LRRK2) and α-synuclein (SNCA) genes are known genetic causes of Parkinson's disease (PD). Recently, a genetic variant in SNCA has been associated with a lower age at onset in idiopathic PD (IPD). We genotyped the SNCA polymorphism rs356219 in 84 LRRK2-associated PD patients carrying the G2019S mutation. We found that a SNCA genetic variant is associated with an earlier age at onset in LRRK2-associated PD. Our results support the notion that SNCA variants can modify the pathogenic effect of LRRK2 mutations as described previously for IPD.
    Journal of Molecular Neuroscience 06/2012; 48(1):245-7. · 2.89 Impact Factor
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    ABSTRACT: Progranulin gene (GRN) mutations cause frontotemporal lobar degeneration (FTLD) with TDP43-positive inclusions, although its clinical phenotype is heterogeneous and includes patients classified as behavioral variant-FTLD (bvFTLD), progressive non-fluent aphasia (PNFA), corticobasal syndrome, Alzheimer's disease (AD), or Parkinson's disease (PD). Our main objective was to study if low serum progranulin protein (PGRN) levels may detect GRN mutations in a Spanish cohort of patients with FTLD or AD. Serum PGRN levels were measured in 112 subjects: 17 bvFTLD, 20 PNFA, 4 semantic dementia, 34 sporadic AD, 9 AD-PSEN1 mutation carriers, 10 presymptomatic-PSEN1 mutation carriers, and 18 control individuals. We detected 5 patients with PGRN levels below 94 ng/mL: two of them had a clinical diagnosis of bvFTLD, two of PNFA, and one of AD. The screening for GRN mutations detected two probable pathogenic mutations (p.C366fsX1 and a new mutation: p.V279GfsX5) in three patients and one mutation of unclear pathogenic nature (p.C139R) in one patient. The other patient showed a normal GRN sequence but carried a PRNP gene mutation. We observed no differences in serum PGRN levels between controls (mean = 145.5 ng/mL, SD = 28.5) and the other neurodegenerative diseases, except for the carriers of pathological GRN gene mutations (mean = 50.5 ng/mL, SD = 21.2). Null GRN mutation carriers also showed lower serum PGRN levels than the patient who was a carrier of p.C139R (92.3 ng/mL) and the one who was a carrier of the PRNP mutation (76.9 ng/mL). In conclusion, we detected GRN null mutations in patients with severely reduced serum PGRN levels, but not in patients with slightly reduced PGRN levels.
    Journal of Alzheimer's disease: JAD 05/2012; 31(3):581-91. · 4.17 Impact Factor
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    ABSTRACT: LRRK2 mutations are the most common genetic cause of Parkinson's disease (PD). We performed a whole-genome RNA profiling of locus coeruleus post-mortem tissue, a histopathologically affected brain tissue in PD, from idiopathic PD (IPD) and LRRK2-associated PD patients. The differentially expressed genes found in IPD and LRRK2-associated PD are involved in the gene ontology terms of synaptic transmission and neuron projection. In addition, differentially expressed genes in the IPD group are associated with immune system related pathways. Specifically, the study performed highlights the presence of differential expression of genes located in the chromosome 6p21.3 belonging to the class II HLA. Our findings support the hypothesis of a potential role of neuroinflammation and the involvement of the HLA genetic area in IPD pathogenesis. Future studies are necessary to shed light on the relation of immune system related pathways in the etiopathogenesis of PD.
    Brain research 05/2012; 1466:152-7. · 2.46 Impact Factor
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    ABSTRACT: LRRK2 mutations are the most common genetic cause of Parkinson's disease (PD). We performed a whole-genome RNA profiling of putamen tissue from idiopathic PD (IPD), LRRK2-associated PD (G2019S mutation), neurologically healthy controls and one asymptomatic LRRK2 mutation carrier, by using the Genechip Human Exon 1.0-ST Array. The differentially expressed genes found in IPD revealed an alteration of biological pathways related to long-term potentiation (LTP), GABA receptor signalling, and calcium signalling pathways, among others. These pathways are mainly related with cell signalling cascades and synaptic plasticity processes. They were also altered in the asymptomatic LRRK2 mutation carrier but not in the LRRK2-associated PD group. The expression changes seen in IPD might be attributed to an adaptive consequence of a dysfunction in the dopamine transmission. The lack of these altered molecular pathways in LRRK2-associated PD patients suggests that these cases could show a different molecular response to dopamine transmission impairment.
    Neurobiology of Disease 09/2011; 45(1):462-8. · 5.62 Impact Factor
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    ABSTRACT: 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.
    Neuroscience Letters 10/2010; 487(2):169-73. · 2.03 Impact Factor