Aurélie Kas

Long-term safety and tolerability of ProSavin, a lentiviral vector-based gene therapy for Parkinson's disease: a dose escalation, open-label, phase 1/2 trial

BACKGROUND Parkinsons disease is typically treated with oral dopamine replacement therapies; however, long-term treatment leads to motor complications and, occasionally, impulse control disorders caused by intermittent stimulation of dopamine receptors and off-target effects, respectively. We aimed to assess the safety, tolerability, and efficacy of bilateral, intrastriatal delivery of ProSavin, a lentiviral vector-based gene therapy aimed at restoring local and continuous dopamine production in patients with advanced Parkinsons disease. METHODS We undertook a phase 1/2 open-label trial with 12-month follow-up at two study sites (France and UK) to assess the safety and efficacy of ProSavin after bilateral injection into the putamen of patients with Parkinsons disease. All patients were then enrolled in a separate open-label follow-up study of long-term safety. Three doses were assessed in separate cohorts: low dose (1·9×10(7) transducing units [TU]); mid dose (4·0×10(7) TU); and high dose (1×10(8) TU). Inclusion criteria were age 48-65 years, disease duration 5 years or longer, motor fluctuations, and 50% or higher motor response to oral dopaminergic therapy. The primary endpoints of the phase 1/2 study were the number and severity of adverse events associated with ProSavin and motor responses as assessed with Unified Parkinsons Disease Rating Scale (UPDRS) part III (off medication) scores, at 6 months after vector administration. Both trials are registered at ClinicalTrials.gov, NCT00627588 and NCT01856439. FINDINGS 15 patients received ProSavin and were followed up (three at low dose, six mid dose, six high dose). During the first 12 months of follow-up, 54 drug-related adverse events were reported (51 mild, three moderate). Most common were increased on-medication dyskinesias (20 events, 11 patients) and on-off phenomena (12 events, nine patients). No serious adverse events related to the study drug or surgical procedure were reported. A significant improvement in mean UPDRS part III motor scores off medication was recorded in all patients at 6 months (mean score 38 [SD 9] vs 26 [8], n=15, p=0·0001) and 12 months (38 vs 27 [8]; n=15, p=0·0001) compared with baseline. INTERPRETATION ProSavin was safe and well tolerated in patients with advanced Parkinsons disease. Improvement in motor behaviour was observed in all patients. FUNDING Oxford BioMedica.

Is 18F‐fluorodeoxyglucose positron emission tomography scanning a reliable way to assess disease activity in takayasu arteritis?

OBJECTIVE (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scanning has been proposed as a new way of assessing disease activity in Takayasu arteritis (TA), but previous studies have used the nonvalidated National Institutes of Health (NIH) global activity criteria, and thus might be biased. This study was undertaken to determine the value of PET scanning for assessment of disease activity in TA, by comparing PET scan data with clinical, biologic, and magnetic resonance imaging (MRI) data assessed separately. METHODS Twenty-eight patients with TA (according to the American College of Rheumatology criteria) underwent a total of 40 PET scans. Images were reviewed by 2 pairs of independent nuclear medicine physicians and assessed for pattern and intensity of vascular uptake. TA activity data were obtained within 15 days of the PET scans. RESULTS PET scanning revealed abnormal vascular uptake in 47% of the 40 examinations. The uptake intensity grade was 0 in 7 scans, grade 1 in 7 scans, grade 2 in 13 scans, and grade 3 in 13 scans. Morphologic analysis was conducted by grading the pattern of the vascular uptake as diffuse (73%), segmental (20%), or focal (13%). There was a trend toward an association between clinically active disease and the semiquantitative assessment of FDG uptake (P = 0.08). We found no statistical association between levels of acute-phase reactants and intensity of uptake. There was no significant association between the semiquantitative assessment of FDG uptake and the presence of vascular wall thickening (P = 0.23), gadolinium uptake (P = 0.73), or the presence of vascular wall edema (P = 0.56). CONCLUSION Our findings indicate that there is no association between FDG vascular uptake intensity and clinical, biologic, or MRI assessment of disease activity. Previous studies using the nonvalidated NIH global activity criteria are likely biased.

Neural correlates of cognitive impairment in posterior cortical atrophy

With the prospect of disease-modifying drugs that will target the physiopathological process of Alzheimers disease, it is now crucial to increase the understanding of the atypical focal presentations of Alzheimers disease, such as posterior cortical atrophy. This study aimed to (i) characterize the brain perfusion profile in posterior cortical atrophy using regions of interest and a voxel-based approach; (ii) study the influence of the disease duration on the clinical and imaging profiles; and (iii) explore the correlations between brain perfusion and cognitive deficits. Thirty-nine patients with posterior cortical atrophy underwent a specific battery of neuropsychological tests, mainly targeting visuospatial functions, and a brain perfusion scintigraphy with 99mTc-ethyl cysteinate dimer. The imaging analysis included a comparison with a group of 24 patients with Alzheimers disease, matched for age, disease duration and Mini-Mental State Examination, and 24 healthy controls. The single-photon emission computed tomography profile in patients with posterior cortical atrophy was characterized by extensive and severe hypoperfusion in the occipital, parietal, posterior temporal cortices and in a smaller cortical area corresponding to the frontal eye fields (Brodmann areas 6/8). Compared with patients with Alzheimers disease, the group with posterior cortical atrophy showed more severe occipitoparietal hypoperfusion and higher perfusion in the frontal, anterior cingulate and mesiotemporal regions. When considering the disease duration, the functional changes began and remained centred on the posterior lobes, even in the late stage. Correlation analyses of brain perfusion and neuropsychological scores in posterior cortical atrophy highlighted the prominent role of left inferior parietal damage in acalculia, Gerstmanns syndrome, left-right indistinction and limb apraxia, whereas damage to the bilateral dorsal occipitoparietal regions appeared to be involved in Bálints syndrome. Our findings provide new insight into the natural history of functional changes according to disease duration and highlight the role of parietal and occipital cortices in the cognitive syndromes that characterize the posterior cortical atrophy.

Validation of a Standardized Normalization Template for Statistical Parametric Mapping Analysis of 123I-FP-CIT Images

123I-FP-CIT (123I-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane) is a SPECT dopamine transporter (DAT) tracer that probes dopaminergic cell loss in Parkinsons disease (PD). Quantification of 123I-FP-CIT images is performed at equilibrium using a ratio (BR) of specific (striatal) to nonspecific (occipital) uptake with values obtained from regions of interest drawn manually over these structures. Statistical parametric mapping (SPM) is a fully automated voxel-based statistical approach that has great potential in the context of DAT imaging. However, the accuracy of the spatial normalization provided by SPM has not been validated for 123I-FP-CIT images. Our first aim was to create an 123I-FP-CIT template that does not require the acquisition of patient-specific MRI and to validate the spatial normalization procedure. Next, we hypothesized that this customized template could be used by different SPECT centers without affecting the outcomes of imaging analyses. Methods: The spatial normalization to the customized template created with SPM (template A1) was validated using 123I-FP-CIT images obtained from 6 subjects with essential tremor (ET) with normal DAT status and 6 PD patients. Variability in BR values due to the normalization was evaluated using striatal volume of interest (VOI). To determine whether different SPECT centers could use a unique 123I-FP-CIT template, we generated 3 other 123I-FP-CIT templates using different subjects and image-processing schemes. The interchangeability of these templates was assessed using (a) putamen BR values analyzed with the intraclass correlation coefficient (ICC) and the Bland–Altman graphical analysis, and (b) SPM analysis comparing the results of group comparisons—that is, ET versus PD, obtained after normalization to each of the 4 templates. Results: There was no significant difference between pre- and postnormalization striatal BR values in our study. The mean variability calculated with putamen VOI values after normalization to each template was <10%, with the lowest ICC of 98%. Intergroup analyses performed with VOI and SPM approaches provided similar results independently of the template used. Conclusion: SPM normalization was accurate even in subjects with low striatal 123I-FP-CIT uptake, making it a promising approach for automatic analysis of 123I-FP-CIT images using a single customized template at different centers.

Decrease of nicotinic receptors in the nigrostriatal system in Parkinson's disease

Smoking is associated with a lower incidence of Parkinsons disease (PD), which might be related to a neuroprotective action of nicotine. Postmortem studies have shown a decrease of cerebral nicotinic acetylcholine receptors (nAChRs) in PD. In this study, we evaluated the decrease of nAChRs in PD in vivo using positron emission tomography (PET), and we explored the relationship between nAChRs density and PD severity using both clinical scores and the measurement of striatal dopaminergic function. Thirteen nondemented patients with PD underwent two PET scans, one with 6-[18F]fluoro-3,4-dihydroxy-l-phenylalanine (6-[18F]fluoro-l-DOPA) to measure the dopaminergic function and another with 2-[18F]fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine (2-[18F]fluoro-A-85380), a radiotracer with high affinity for the nAChRs. Distribution volumes (DVs) of 2-[18F]fluoro-A-85380 measured in the PD group were compared with those obtained from six nonsmoking healthy controls, with regions-of-interest and voxel-based approaches. Both analyses showed a significant (P<0.05) decrease of 2-[18F]fluoro-A-85380 DV in the striatum (10%) and substantia nigra (14.9%) in PD patients. Despite the wide range of PD stages, no correlation was found between DV and the clinical and PET markers of PD severity.

Quantitative simultaneous 99mTc-ECD/123I-FP-CIT SPECT in Parkinson’s disease and multiple system atrophy

PurposeThe purpose of this study was to investigate the feasibility and utility of dual-isotope SPECT for differential diagnosis of idiopathic Parkinson’s disease (IPD) and multiple system atrophy (MSA).MethodsSimultaneous 99mTc-ECD/123I-FP-CIT studies were performed in nine normal controls, five IPD patients, and five MSA patients. Projections were corrected for scatter, cross-talk, and high-energy penetration, and iteratively reconstructed while correcting for patient-specific attenuation and variable collimator response. Perfusion and dopamine transporter (DAT) function were assessed using voxel-based statistical parametric mapping (SPM2) and volume of interest quantitation. DAT binding potential (BP) and asymmetry index (AI) were estimated in the putamen and caudate nucleus.ResultsStriatal BP was lower in IPD (55%) and MSA (23%) compared to normal controls (p<0.01) , and in IPD compared to MSA (p<0.05). AI was greater for IPD than for MSA and controls in both the caudate nucleus and the putamen (p<0.05). There was significantly decreased perfusion in the left and right nucleus lentiformis in MSA compared to IPD and controls (p<0.05).ConclusionDual-isotope studies are both feasible in and promising for the diagnosis of parkinsonian syndromes.

[123I]-FP-CIT and [99mTc]-HMPAO single photon emission computed tomography in a new sporadic case of rapid-onset dystonia–parkinsonism

UNLABELLED Rapid-onset dystonia-parkinsonism (RDP) is a rare, autosomal-dominantly inherited syndrome characterized by abrupt onset, over hours to days, of dystonic and parkinsonian symptoms. To date, RDP has been described in a small number of families, and in only four sporadic cases. METHODS We here report a new sporadic case of RDP who has a novel de novo mutation in the ATP1A3 gene. Striatal dopamine transporters have been assessed quantitatively using [123I]-FP-CIT SPECT. A volume of interest (VOI) was drawn within the occipital cortex to obtain non-specific activity and specific to non-specific binding ratios (BR) were calculated. A single template of predefined VOI 3D-drawn on right and left caudate nucleus and putamen was applied to the spatially normalized BR images. BR values were compared to those obtained from an age-matched control group and from a group of patients suffering from Parkinsons disease (Hoehn and Yahr score 2 or 3). A [99mTc]-HMPAO cerebral blood flow study was also performed. RESULTS In the control group, BR values (mean+/-Standard Deviation) were 3.5+/-0.4 for the left striatum and 3.3+/-0.3 for the right one. RDP patients values were 3 and 2.7, respectively. In the Parkinson group, values were 1.6+/-0.3 and 1.7+/-0.4, respectively. [99mTc]-HMPAO scan showed homogeneous cortical and sub-cortical perfusion. CONCLUSION Quantification of striatal [123I]-FP-CIT uptake in a new sporadic case of RDP with a novel mutation in the ATP1A3 gene showed values just within the range of normality. [99mTc]-HMPAO scan was normal.

Feeling unreal: a functional imaging study in patients with Kleine-Levin syndrome

Kleine-Levin syndrome is characterized by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, derealization and behavioural disturbances. Between episodes, patients have normal sleep, mood and behaviour. Functional imaging studies performed in small series of patients with Kleine-Levin syndrome with visual or semi-quantitative, uncontrolled analysis yielded equivocal brain changes. Using whole brain voxel-based group analysis, we compared brain perfusion scintigraphy during and between episodes in consecutive patients with Kleine-Levin syndrome versus healthy control subjects and correlated perfusion changes with disease severity and symptoms, focusing on less studied but disabling symptoms, such as apathy and derealization. During asymptomatic periods, 41 patients (mean age of 22.3 ± 8.1 years, 56.1% male) and 15 age- and sex-matched healthy control subjects underwent single-photon emission computed tomography scanning with technetium-99m ethyl cysteinate dimer. Eleven patients repeated the test during a symptomatic period. Compared with controls, patients during asymptomatic periods had persistent hypoperfusion in the hypothalamus, the thalamus (mainly the right posterior part), the caudate nucleus, and cortical associative areas, including the anterior cingulate, (Brodmann area 25), the orbito-frontal (Brodmann area 11) and the right superior temporal cortices (Brodmann area 22), extending to the insula (P < 0.001 in all area). Two additional hypoperfused areas emerged during symptomatic periods (P < 0.001), located in the right dorsomedial prefrontal cortex (Brodmann area 8) and the right parieto-temporal junction (Brodmann areas 22 and 39). These two areas were more affected between episodes, when the mean episode duration was longer (r = -0.53; P < 0.001). The score for the Depersonalization/Derealization Inventory during symptomatic periods strongly correlated with the hypoperfusion of the right (r = -0.74, P < 0.001) and left (r = -0.59, P < 0.005) parieto-temporal junctions. No hyperperfusion was found. Because the parieto-temporal junction (including the angular gyrus) is involved in cross-modal association between somatosensory (body knowledge), auditory and visual information, the robust hypoperfusions and correlations observed in this area may underlie the striking derealization reported by patients during episodes. Defects in the dorsomedial prefrontal cortex may cause apathy. Persistent hypoperfusion in the diencephalic and associative cortical area during asymptomatic periods is a marker of the disease, suggestive of a scenario wherein patients compensate for these deficient circuitries.

Motor cortex and hippocampus are the two main cortical targets in LGI1-antibody encephalitis

Encephalitis associated with antibodies against leucine-rich glioma-inactivated 1 (LGI1) protein is increasingly recognized as an auto-immune disorder associated with characteristic tonic-dystonic seizures. The cortical or subcortical origin of these motor events is not clear. Some patients also present with different epileptic seizures and with cognitive impairment. The frequency of these features and their timing during the natural history of this encephalitis have not been fully described. We therefore reviewed data from 34 patients harbouring antibodies against LGI1 protein (21-81 years, median age 64) referred to the French Reference Centre for Neurological Paraneoplastic Syndrome. Three types of evidence suggested tonic-dystonic seizures were of cortical origin: (i) a slow, unilateral, frontal electroencephalographic wave, of duration ∼580 ms and amplitude ∼71 µV, preceded the contralateral tonic-dystonic seizures in simultaneous electroencephalographic and myographic records from seven of seven patients tested; (ii) 18-Fluorodeoxyglucose imaging revealed a strong hypermetabolism in primary motor cortex, controlateral to the affected limb, during encephalitis for five patients tested, as compared with data from the same patients after remission or from 16 control subjects; and (iii) features of polymyographic records of tonic-dystonic seizure events pointed to a cortical origin. Myoclonic patterns with brief, rhythmic bursts were present in three of five patients tested and a premyoclonic potential was identified in the cortex of one patient. Initially during encephalitis, 11 of 34 patients exhibited tonic-dystonic seizures (32%). Distinct epileptic syndromes were evident in 13 patients (38%). They were typically simple, focal seizures from the temporal lobe, consisting of vegetative symptoms or fear. At later stages, 22 of 32 patients displayed tonic-dystonic seizures (68%) and 29 patients presented frequent seizures (91%) including status epilepticus. Cognitive impairment, either anterograde amnesia or confusion was evident in 30 of 34 patients (88%). Brain imaging was normal in patients with isolated tonic-dystonic seizures; in patients with limbic symptoms it revealed initially a hippocampal hyperintensity in 8 of 19 patients (42%) and 17 of 24 patients (70%) at later stages. Our data suggest that the major signs of LGI1-antibody encephalitis can be linked to involvement of motor cortex and hippocampus. They occur in parallel with striatum involvement. One of these cortical targets is involved, often unilaterally at disease onset. As the encephalitis progresses, in the absence of immunomodulatory treatment, the second cortical target is affected and effects become bilateral. Progression to the second cortical target occurs with a variable delay of days to several months.

Differential automatic diagnosis between Alzheimer's disease and frontotemporal dementia based on perfusion SPECT images

OBJECTIVE Alzheimers disease (AD) and frontotemporal dementia (FTD) are among the most frequent neurodegenerative cognitive disorders, but their differential diagnosis is difficult. The aim of this study was to evaluate an automatic method returning the probability that a patient suffers from AD or FTD from the analysis of brain perfusion single photon emission computed tomography images. METHODS AND MATERIALS A set of 116 descriptors corresponding to the average activity in regions of interest was calculated from the images of 82 AD and 91 FTD patients. A set of linear (logistic regression and linear discriminant analysis) and non-linear (support vector machines, k-nearest neighbours, multilayer perceptron and kernel logistic PLS) classification methods was subsequently used to ascertain diagnoses. Validation was carried out by means of the leave-one-out protocol. Diagnoses by the classifier and by four physicians (visual assessment) were compared. Since images were acquired in different hospitals, the impact of the medical centre on the diagnosis of both the classifier and the physicians was investigated. RESULTS Best results were obtained with support vector machine and partial least squares regression coupled with k-nearest neighbours methods (PLS+K-NN), with an overall accuracy of 88%. PLS+K-NN was however considered as the best method since performances obtained with leave-one-out cross-validation were closer to whole-database learning. The performances of the classifier were higher than those of experts (accuracy ranged from 65 to 72%). Physicians found it more difficult to diagnose the images from centres other than their own, and it affected their performances. CONCLUSIONS The performances obtained by the classifier for the differential diagnosis of AD and FTD were found convincing. It could help physicians in daily practice, particularly when visual assessment is inconclusive, or when dealing with multicentre data.