Claire Paquet

Hôpital Lariboisière - Fernand-Widal (Hôpitaux Universitaires Sant-Louis, Lariboisière, Fernand-Widal), Lutetia Parisorum, Île-de-France, France

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Publications (68)427.59 Total impact

  • F Mouton-Liger, A-S Rebillat, S Gourmaud, C Paquet, A Leguen, J Dumurgier, P Bernadelli, V Taupin, L Pradier, T Rooney, J Hugon
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    ABSTRACT: Brain thiamine homeostasis has an important role in energy metabolism and displays reduced activity in Alzheimer's disease (AD). Thiamine deficiency (TD) induces regionally specific neuronal death in the animal and human brains associated with a mild chronic impairment of oxidative metabolism. These features make the TD model amenable to investigate the cellular mechanisms of neurodegeneration. Once activated by various cellular stresses, including oxidative stress, PKR acts as a pro-apoptotic kinase and negatively controls the protein translation leading to an increase of BACE1 translation. In this study, we used a mouse TD model to assess the involvement of PKR in neuronal death and the molecular mechanisms of AD. Our results showed that the TD model activates the PKR-eIF2α pathway, increases the BACE1 expression levels of Aβ in specific thalamus nuclei and induces motor deficits and neurodegeneration. These effects are reversed by PKR downregulation (using a specific inhibitor or in PKR knockout mice).
    Cell Death & Disease 01/2015; 6:e1594. · 5.18 Impact Factor
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    ABSTRACT: Active Aβ immunotherapy in Alzheimer's disease (AD) induces removal of Aβ and phosphorylated tau (ptau). Glycogen Synthase Kinase (GSK)-3β is a kinase, responsible for phosphorylation of tau, activation of which can be induced by phosphorylated double-stranded RNA dependent protein kinase (pPKR). Using a post-mortem cohort of immunised AD cases, we investigated the effect of Aβ immunisation on GSK-3β expression and pPKR. We immunostained 11 immunised AD cases and 28 unimmunised AD cases for active, inactive and total GSK-3β, and for pPKR. Quantification of protein load was performed in the hippocampal region including CA1, subiculum and entorhinal cortex. All 3 areas showed a significant decrease in the three forms of GSK-3β (P<0.05) and a non-significant trend towards lower pPKR load in the immunised AD cases compared to the unimmunised AD cases. The lower GSK-3β expression generated by Aβ immunotherapy shows evidence of a modification of the signalling pathway induced by GSK-3β leading to the overall reduction of tau, supporting the contention that in humans, GSK-3β unifies Aβ and tau-related neuropathology. This article is protected by copyright. All rights reserved.
    Neuropathology and Applied Neurobiology 12/2014; · 4.97 Impact Factor
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    ABSTRACT: Alzheimer disease is characterized by cognitive decline, senile plaques of β-amyloid (Aβ) peptides, neurofibrillary tangles composed of hyperphosphorylated τ proteins and neuronal loss. Aβ and τ are useful markers in the cerebrospinal fluid (CSF). C-Jun N-terminal kinases (JNKs) are serine-threonine protein kinases activated by phosphorylation and involved in neuronal death. In this study, Western blots, enzyme-linked immunosorbent assay and histological approaches were used to assess the concentrations of Aβ, τ and JNK isoforms in postmortem brain tissue samples (10 Alzheimer disease and 10 control) and in CSF samples from 30 living patients with Alzheimer disease and 27 controls with neurologic disease excluding Alzheimer disease. Patients with Alzheimer disease were followed for 1-3 years and assessed using Mini-Mental State Examination scores. The biochemical and morphological results showed a significant increase of JNK3 and phosphorylated JNK levels in patients with Alzheimer disease, and JNK3 levels correlated with Aβ42 levels. Confocal microscopy revealed that JNK3 was associated with Aβ in senile plaques. The JNK3 levels in the CSF were significantly elevated in patients with Alzheimer disease and correlated statistically with the rate of cognitive decline in a mixed linear model. The study involved different samples grouped into 3 small cohorts. Evaluation of JNK3 in CSF was possible only with immunoblot analysis. We found that JNK3 levels are increased in brain tissue and CSF from patients with Alzheimer disease. The finding that increased JNK3 levels in CSF could reflect the rate of cognitive decline is new and merits further investigation.
    Journal of psychiatry & neuroscience: JPN 12/2014; 39(6):140062. · 7.49 Impact Factor
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    Alzheimer's and Dementia 11/2014; · 17.47 Impact Factor
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    ABSTRACT: Amyloid β peptide (Aβ) immunization of Alzheimer's disease (AD) patients has been reported to induce amyloid plaque removal but with little impact on cognitive decline. We have explored the consequences of Aβ immunotherapy on neurons in post-mortem brain tissue. Eleven immunized (AN1792, Elan Pharmaceuticals) AD patients were compared to 28 non-immunized AD cases. Immunohistochemistry on sections of neocortex was performed for neuron-specific nuclear antigen (NeuN), neurofilament protein (NFP) and phosphorylated-(p)PKR (pro-apoptotic kinase detected in degenerating neurons). Quantification was performed for pPKR and status spongiosis (neuropil degeneration), NeuN positive neurons/field, curvature of the neuronal processes and interneuronal distance. Data were corrected for age, sex, duration of dementia and APOE genotype and also assessed in relation to Aβ42 and tau pathology, and key features of AD. In non-immunized patients, the degree of neuritic curvature correlated with spongiosis and pPKR, and overall the neurodegenerative markers correlated better with tau pathology than Aβ42 load. Following immunization, spongiosis increased, interneuronal distance increased, while the number of NeuN-positive neurons decreased, consistent with enhanced neuronal loss. However neuritic curvature was reduced and pPKR was associated with Aβ removal (p=0.001) in immunized patients. In AD, associations of spongiosis status, curvature ratio and pPKR load with microglial markers Iba1, CD68 and CD32 suggest a role for microglia in neurodegeneration. After immunization, correlations were detected between the number of NeuN-positive neurons and pPKR with Iba1, CD68 and CD64, suggesting that microglia are involved in the neuronal loss. Our findings suggest that in established AD this form of active Aβ immunization may predominantly accelerate loss of damaged degenerating neurons. This interpretation is consistent with in vivo imaging indicating an increased rate of cerebral atrophy in immunized AD patients.
    The Journal of Pathology 11/2014; · 7.33 Impact Factor
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    ABSTRACT: Context Lumbar puncture (LP) is a common medical procedure for which no valid consensus exists in situations of hemorrhagic or thrombotic risk. The aim of this study was to identify the opinion-guided practices of LP at a national level. Methods A national opinion survey on Internet. An anonymous questionnaire of 19 questions collecting information about the LP practice for patients with hemorrhagic or thrombotic risks. Results We sent 632 e-mails with the link of the survey and obtained 211 responses in six weeks. None of the responses was unanimous for any of the 13 different clinical situations proposed. Six practices were reported as adopted by the majority of participants, six by more than one-third. Reports of practices were highly variable, particularly for the minimum platelets count accepted, for the management of patients taking two antiplatelet agents or newer anticoagulant agents. Discussion and conclusion These results underline the heterogeneity of practices and the lack of recommendations. The establishment of a clear consensus in this area seems essential to guide practices in the future. In order to increase the representativeness of our responses, the survey is still going on online and will be open for all practitioners who wish to participate (http://www.surveymonkey.com/s/hemopl).
    Revue Neurologique 11/2014; · 0.60 Impact Factor
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    ABSTRACT: Lumbar puncture (LP) is a common medical procedure for which no valid consensus exists in situations of hemorrhagic or thrombotic risk. The aim of this study was to identify the opinion-guided practices of LP at a national level.
    Revue Neurologique 10/2014; · 0.60 Impact Factor
  • Alzheimer's and Dementia 07/2014; 10(4):P347. · 17.47 Impact Factor
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    ABSTRACT: Introduction: The relevance of the cerebrospinal fluid (CSF) biomarkers for the diagnosis of Alzheimer's disease (AD) and related disorders is clearly established. However, the question remains on how to use these data, which are often heterogeneous (not all biomarkers being pathologic). The objective of this study is to propose to physicians in memory clinics a biologic scale of probabilities that the patient with cognitive impairments has an Alzheimer's disease (AD) pathologic process. Methods: For that purpose, we took advantage of the multicenter data of our Paris-North, Lille, and Montpellier (PLM) study, which has emerged through the initial sharing of information from these memory centers. Different models combining the CSF levels of amyloid-β 42, tau, and p-tau(181) were tested to generate categories of patients with very low (<10%), low (<25%), high (>75%), and very high predictive values (>90%) for positive AD. In total, 1,273 patients (646 AD and 627 non-AD) from six independent memory-clinic cohorts were included. Results: A prediction model based on logistic regressions achieved a very good stratification of the population but had the disadvantages of needing mathematical optimization and being difficult to use in daily clinical practice. Remarkably, a simple and intuitive model based on the number (from zero to three) of three pathologic CSF biomarkers resulted in a very efficient predictive scale for AD in patients seen in memory clinics. The scale's overall predictive value for AD for the different categories were as follows: class 0, 9.6% (95% confidence interval (CI), 6.0% to 13.2%); class 1, 24.7% (95% CI, 18.0% to 31.3%); class 2, 77.2% (95% CI, 67.8% to 86.5%); and class 3, 94.2% (95% CI, 90.7% to 97.7%). In addition, with this scale, significantly more patients were correctly classified than with the logistic regression. Its superiority in model performance was validated by the computation of the net reclassification index (NRI). The model was also validated in an independent multicenter dataset of 408 patients (213 AD and 195 non-AD). Conclusions: In conclusion, we defined a new scale that could be used to facilitate the interpretation and routine use of multivariate CSF data, as well as helping the stratification of patients in clinical research trials. Introduction Intense research efforts have been conducted to develop and validate biomarkers to predict, detect, and follow up the progression of the disease or impact of potential new disease-modifying treatments of Alzheimer's disease (AD). Brain imaging and biologic biomarkers are now included in the recommended AD diagnostic criteria [1-3]. Various scales or tools are available to physicians involved in AD research for better interpreting the positive or negative re-sults of biomarkers for establishing a clinical diagnosis, such as the detection of hippocampal atrophy with the Scheltens' scale [4] and the positivity of amyloid load on functional brain imaging via the Jack's visual scale [5]. Although biologic cerebrospinal fluid (CSF) bio-markers are among the most studied and validated in clinical practice [6-8], no sort of "visual" scale concerning
    Alzheimer's Research and Therapy 06/2014; 6(3). · 3.50 Impact Factor
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    ABSTRACT: Polymorphism of the apolipoprotein E gene (APOE) plays a role in the level of neuropathological lesions and in drug response in Alzheimer's disease (AD). The aim of this study was to investigate whether the selection of AD patients based on cerebrospinal fluid (CSF) biomarkers assessment may be biased by their APOE distribution. We studied the relationships between APOE genotype and CSF biomarkers levels in a total of 432 patients (AD, n = 244; non-AD, n = 188) explored for cognitive disorders. We studied the distribution of APOE genotypes among AD patient subgroups selected by various cut-offs of CSF biomarkers. Strategies of screening based on CSF Aβ1-42 lead to overselection of ε4/ε4 patients in the AD group. Screening based on tau levels did not change Apoe4 distribution in the AD group. CSF Aβ1-42 discriminated better AD patients with at least one ε4 than AD patients with no ε4. A strong allele-effect relationship was detected between APOE genotype and CSF amyloid-β (Aβ1-42) in AD patients. Selecting AD patients on CSF amyloid levels only may create an overselection of ε4/ε4 carriers, and might potentially bias the population of patients included in clinical trial studies.
    Journal of Neurology 04/2014; · 3.84 Impact Factor
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    ABSTRACT: Cerebrospinal fluid (CSF) biomarkers for Alzheimer's disease (AD) are well validated in clinical research but less in clinical practice. Using a questionnaire, we evaluated the reasons for prescriptions and clinician's expectations concerning CSF biomarkers. The results show that CSF AD biomarkers are mainly required in case of atypical dementia and diagnosis uncertainty that are different from indications in clinical research. In the future, clinicians wish to get new biomarkers that could improve differential diagnosis and could have a good pronostic value. Further studies in routine practice are necessary to precise the role of these biomarkers in the management of patients.
    Journal of Alzheimer's disease: JAD 02/2014; · 3.61 Impact Factor
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    ABSTRACT: Disturbances of affect expression and perception, as well as accuracy of predicting memory difficulties, have been reported in various brain dysfunctional groups. Screening tests of higher cerebral functions seldom sample these dimensions. The goal of this study was to determine if patients with mild cognitive impairment (MCI) of the amnestic type would demonstrate impairments in these domains, as well as show expected memory deficits. Thirty-nine French-speaking patients with a clinical diagnosis of MCI were compared with 39 age- and education-matched normal functioning individuals on the French translation of the Barrow Neurological Institute Screen for Higher Cerebral Functions (BNIS). Patients and controls also made subjective ratings regarding their cognitive and affective functioning in everyday life. Patients with MCI performed significantly worse than controls on the BNIS subtests sampling memory, orientation, affect expression and perception, and accurate prediction of memory performance. They did not differ on other subtests of the BNIS, as predicted. Poor self-awareness (i.e., inaccurate prediction of the number of words one could recall after distraction) correlated with self-reported deficits in several areas of cognitive and affective functioning. This sample of MCI patients demonstrated disturbances not only in memory but also in self-awareness and affect expression and perception on the BNIS. These dimensions should be included in the neuropsychological assessment of patients suspected of MCI. Copyright © 2014 John Wiley & Sons, Ltd.
    International Journal of Geriatric Psychiatry 02/2014; · 3.09 Impact Factor
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    ABSTRACT: Background: Patients with logopenic variant of primary progressive aphasia (lvPPA) display neuropathological differences from typical amnestic Alzheimer's disease (AD). Objective: The aim of the study was to compare cerebrospinal fluid (CSF) biomarker levels between patients with lvPPA due to AD (lvPPA-AD), non-logopenic forms of AD (nlAD), and amnestic mild cognitive impairment due to AD (aMCI-AD). Methods: CSF biomarker concentrations were assessed in 124 patients divided into three groups matched for age, level of education, center, and disease duration: lvPPA-AD (n = 30), nlAD (n = 67). and aMCI-AD (n = 27). Results: p-Tau181 levels were higher in the lvPPA-AD group than in the aMCI-AD group (p < 0.05). Total tau levels were higher in the lvPPA-AD group versus those in the nlAD (p < 0.05) and aMCI-AD (p < 0.001) groups. Conclusions: These results suggest a more pronounced involvement of a taupathy in lvPPA-AD compared to aMCI-AD and a more important neuronal death in lvPPA-AD than in nlAD or aMCI-AD.
    Journal of Alzheimer's disease: JAD 11/2013; · 3.61 Impact Factor
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    ABSTRACT: CSF biomarkers of Alzheimer's disease are well validated in clinical research; however, their pragmatic utility in daily practice is still unappreciated. These biomarkers are used in routine practice according to Health Authority Recommendations. In 604 consecutive patients explored for cognitive disorders, questionnaires were prospectively proposed and filled. Before and after CSF biomarker results, clinicians provided a diagnosis and an estimate of their diagnostic confidence. Analysis has compared the frequency of diagnosis before and after CSF biomarker results using the net reclassification improvement (NRI) method. We have evaluated external validity comparing with data of French Bank National of AD (BNA). A total of 561 patients [Alzheimer's disease (AD), n = 253; non-AD, n = 308] were included (mean age, 68.6 years; women, 52 %). Clinically suspected diagnosis and CSF results were concordant in 65.2 % of cases. When clinical hypothesis and biological results were discordant, a reclassification occurred in favour of CSF biomarkers results in 76.9 %. The NRI was 39.5 %. In addition, the results show a statistically significant improvement in clinician confidence for their diagnosis. In comparison with BNA data, patients were younger and more frequently diagnosed with AD. Clinicians tend to heavily rely on the CSF AD biomarkers results and are more confident in their diagnoses using CSF AD biomarkers. Thus, these biomarkers appear as a key tool in clinical practice.
    Journal of Neurology 10/2013; · 3.84 Impact Factor
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    ABSTRACT: The objective of this study was to analyze differences in biomarker outcomes before and after harmonization of cerebrospinal fluid (CSF) collection tubes in Alzheimer's disease (AD) diagnosis. We analyzed data from French memory centers that switched from different CSF collection tubes to a common one. A total of 1966 patients were included in the study. CSF concentrations of β-amyloid 1-42 (Aβ42), total tau, and phosphorylated tau (p-tau181) were measured in each center using the same commercial enzyme-linked immunoabsorbent assay (ELISA) kits. The diagnostic value of CSF biomarkers according to the type of tube used was then assessed using different cutoffs. The predictive value of Aβ42 was highly affected by the type of collection tube used. The optimal cutoff value for p-tau181 appeared not to be affected by the type of collection tube whereas that of total tau was slightly changed. New optimal cutoff values were then computed. In a routine clinical environment, the selection of the collection tube and biomarker cutoff value makes a major difference in AD biological diagnosis. The use of a common collection tube among different centers will reduce the risk of misdiagnosis and incorrect patient stratification.
    Alzheimer's & dementia: the journal of the Alzheimer's Association 10/2013; · 14.48 Impact Factor
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    ABSTRACT: AIMS: This study aimed to assess the relationship between blood pressure and cognitive function in elderly patients with diabetes mellitus (DM). METHODS: A total of 32 patients with DM aged≥65 years (seven women and 25 men; mean±SD age: 74.3±6.4 years) were included in this cross-sectional study. Relationships between blood pressure and neuropsychological tests were determined using Spearman's rank correlations (ρ) and multivariable linear regression models. RESULTS: Lower diastolic blood pressure was associated with lower scores on the Frontal Assessment Battery (ρ=0.32, P=0.02), longer times to complete the Trail Making Test Part B (ρ=0.51, P=0.003), lower scores for the Finger Tapping Test (ρ=0.36, P=0.046) and less verbal fluency (ρ=0.36, P=0.047). In multivariable models, these relationships were attenuated after adjusting for levels of education. CONCLUSION: There was an association between lower diastolic blood pressure and poorer executive function in this cohort of elderly DM patients. These results underline the importance of systematic cognitive evaluation in elderly patients with DM, and suggest that a too-low diastolic blood pressure may have deleterious effects on mental function. Larger studies in the future are required to confirm these preliminary results.
    Diabetes & Metabolism 05/2013; · 2.85 Impact Factor
  • Revue Neurologique 04/2013; 169:A7. · 0.60 Impact Factor
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    ABSTRACT: Increasing age is the most important risk factor for developing Alzheimer's disease (AD). The aim of this study was to investigate the relationships between age and cerebrospinal fluid (CSF) levels of β-amyloid (Aβ 1-42), total Tau and phosphorylated Tau (pTau-181), in AD and non-AD patients explored for cognitive disorders. 966 patients (AD, n=528; non-AD, n=438) were included between January 2008 and December 2010 (mean age, 69.5years; mean MMSE, 20.2) from three French memory centers. Multivariable linear regression models were used to study the relationship between CSF biomarker levels and age in AD and non-AD patients. The capacity of each CSF biomarker in discriminating patients was evaluated using the area under the receiver-operating characteristic (ROC) curves by quartile of distribution of age. In AD patients, older age was associated with higher CSF Aβ 1-42 and lower Tau levels. Conversely, in non-AD patients, age was associated with lower CSF Aβ 1-42, higher Tau, and higher pTau-181 levels. In sex-stratified analysis, these relationships were significant only in women. Using ROC curve analysis, CSF AD biomarkers were more discriminant in younger patients than in older ones. In this clinically-based study, younger patients with AD had exacerbated CSF anomalies compared to older patients with AD. CSF biomarkers were more discriminant in younger patients than in older ones for the diagnosis of AD, especially in women. These results support the idea of an overlap in AD neuropathological lesions in oldest subjects with or without AD.
    Neurobiology of Disease 02/2013; · 5.62 Impact Factor
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    ABSTRACT: The cerebrospinal fluid (CSF) levels of the proapoptotic kinase R (PKR) and its phosphorylated PKR (pPKR) are increased in Alzheimer's disease (AD), but whether CSF PKR concentrations are associated with cognitive decline in AD patients remain unknown. In this study, 41 consecutive patients with AD and 11 patients with amnestic mild cognitive impairment (aMCI) from our Memory Clinic were included. A lumbar puncture was performed during the following month of the clinical diagnosis and Mini-Mental State Examination (MMSE) evaluations were repeated every 6 months during a mean follow-up of 2 years. In AD patients, linear mixed models adjusted for age and sex were used to assess the cross-sectional and longitudinal associations between MMSE scores and baseline CSF levels of Aβ peptide (Aβ 1-42), Tau, phosphorylated Tau (p-Tau 181), PKR and pPKR. The mean (SD) MMSE at baseline was 20.5 (6.1) and MMSE scores declined over the follow-up (-0.12 point/month, standard error [SE] = 0.03). A lower MMSE at baseline was associated with lower levels of CSF Aβ 1-42 and p-Tau 181/Tau ratio. pPKR level was associated with longitudinal MMSE changes over the follow-up, higher pPKR levels being related with an exacerbated cognitive deterioration. Other CSF biomarkers were not associated with MMSE changes over time. In aMCI patients, mean CSF biomarker levels were not different in patients who converted to AD from those who did not convert.These results suggest that at the time of AD diagnosis, a higher level of CSF pPKR can predict a faster rate of cognitive decline.
    PLoS ONE 01/2013; 8(1):e53587. · 3.53 Impact Factor
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    ABSTRACT: The French Alzheimer's Disease Plan aims, in an unprecedented national effort, to develop research, promote optimal diagnosis, and take better care of patients. In order to evaluate the clinical interest and use of cerebrospinal fluid (CSF) biomarkers, a data-sharing project, the PLM (Paris-North, Lillem and Montpellier) study has emerged through collaboration between these memory centers, already involved in this field. The revised Alzheimer's disease (AD) diagnosis criteria include CSF biomarkers, but little is known about their use in routine clinical practice. To evaluate their interest and diagnostic accuracy in routine AD diagnosis, a cohort of 677 patients from Montpellier was first analyzed. The results were then validated through the analysis of a second cohort of 638 patients from Lille and Paris-Nord. Diagnoses of AD and other dementias were established by multidisciplinary expert teams, based on neuropsychological exams and structural brain imaging, blinded from CSF results. CSF amyloid-β, tau, and p-tau concentrations were measured for all patients. Receiver-operating characteristic curves were used to define cut-offs and evaluate the ability of each biomarker to discriminate AD from other diagnoses. We showed that p-tau outperformed other biomarkers for discriminating AD from non-AD patients and presents a clear clinical interest. The other biomarkers also showed relevant variations especially when the differential AD diagnoses were taken into account. Altogether we could demonstrate in both mono-centric and multi-centric cohorts from memory clinics the capacity of CSF biomarkers to discriminate AD from non-AD patients in clinical routine with a high sensitivity and specificity.
    Journal of Alzheimer's disease: JAD 11/2012; · 3.61 Impact Factor

Publication Stats

260 Citations
427.59 Total Impact Points

Institutions

  • 2010–2013
    • Hôpital Lariboisière - Fernand-Widal (Hôpitaux Universitaires Sant-Louis, Lariboisière, Fernand-Widal)
      Lutetia Parisorum, Île-de-France, France
    • Paris Diderot University
      Lutetia Parisorum, Île-de-France, France
  • 2012
    • Hôpital Saint-Louis (Hôpitaux Universitaires Saint-Louis, Laboisière, Fernand-Widal)
      Lutetia Parisorum, Île-de-France, France
  • 2011
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
  • 2008
    • Assistance Publique – Hôpitaux de Paris
      Lutetia Parisorum, Île-de-France, France
  • 2007
    • Université de Poitiers
      Poitiers, Poitou-Charentes, France