Clinical impairment in premanifest and early Huntington's disease is associated with regionally specific atrophy

TRACK‐HD is a multicentre longitudinal observational study investigating the use of clinical assessments and 3‐Tesla magnetic resonance imaging as potential biomarkers for future therapeutic trials in Huntington's disease (HD). The cross‐sectional data from this large well‐characterized dataset provide the opportunity to improve our knowledge of how the underlying neuropathology of HD may contribute to the clinical manifestations of the disease across the spectrum of premanifest (PreHD) and early HD. Two hundred and thirty nine gene‐positive subjects (120 PreHD and 119 early HD) from the TRACK‐HD study were included. Using voxel‐based morphometry (VBM), grey and white matter volumes were correlated with performance in four domains: quantitative motor (tongue force, metronome tapping, and gait); oculomotor [anti‐saccade error rate (ASE)]; cognition (negative emotion recognition, spot the change and the University of Pennsylvania smell identification test) and neuropsychiatric measures (apathy, affect and irritability). After adjusting for estimated disease severity, regionally specific associations between structural loss and task performance were found (familywise error corrected, P < 0.05); impairment in tongue force, metronome tapping and ASE were all associated with striatal loss. Additionally, tongue force deficits and ASE were associated with volume reduction in the occipital lobe. Impaired recognition of negative emotions was associated with volumetric reductions in the precuneus and cuneus. Our study reveals specific associations between atrophy and decline in a range of clinical modalities, demonstrating the utility of VBM correlation analysis for investigating these relationships in HD. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.     

Surrogate markers for cerebral blood flow correlate with [18F]‐fallypride binding potential at dopamine D2/3 receptors in human striatum

Positron emission tomography (PET) with the high affinity dopamine D_2/3 receptor ligand [¹⁸F]‐fallypride affords estimates of the binding potential (BP_ND) in extra‐striatal regions of low receptor abundance, but the sufficient recording time for accurate measurements in striatum has been called into question. We have earlier argued that transient equilibrium measurements are obtained in striatum with [¹⁸F]‐fallypride PET recordings of 3 h duration, which may be the practical limit for clinical investigations without interrupted scanning. However, the high extraction fraction of [¹⁸F]‐fallypride predicts flow‐dependence of tracer delivery to brain, which may be a source of variance of the apparent BP_ND in regions of high binding. To test this prediction, we conducted a retrospective analysis of [¹⁸F]‐fallypride PET data from a group of 50 healthy volunteers (age 18–58 years [mean ± SD: 32.6 ± 10.6), who had participated in clinical studies without arterial input measurements. We used the initial 120‐s integral (AUC) of the venous confluence (VC) as a surrogate marker for cerebral blood flow (CBF) and tested for correlations between regional estimates of BP_ND calculated by the simplified reference tissue model (SRTM) and the individual VC‐AUC. The magnitude of BP_ND in a high binding region (putamen), but not in a low binding region (thalamus) correlated positively with VC‐AUC, suggesting that approximately 9% of the variance in the [¹⁸F]‐fallypride BP_ND in putamen can be attributed to individual differences in this surrogate marker for CBF, a contribution equal in magnitude to the effects of age on BP_ND in putamen of the present healthy control group. Synapse, 2013. © 2012 Wiley Periodicals, Inc.     

Accuracy of the national institute for neurological disorders and stroke/society for progressive supranuclear palsy and neuroprotection and natural history in Parkinson plus syndromes criteria for the diagnosis of progressive supranuclear palsy

Autopsy is the diagnostic gold standard for progressive supranuclear palsy (PSP). The National Institute of Neurological Disorders and Stroke and Society for Progressive Supranuclear Palsy (NINDS‐SPSP) criteria for the clinical diagnosis of “probable” PSP are thought to possess high specificity and low sensitivity. The NINDS‐SPSP criteria for “possible” PSP are considered to increase sensitivity at the expense of specificity. The Neuroprotection and Natural History in Parkinson Plus Syndromes (NNIPPS) criteria are intended to improve sensitivity while maintaining high specificity. The aim of this study was to conduct a clinicopathological evaluation of the NINDS‐SPSP and NNIPPS criteria in tertiary neurological centers. Defined clinical features and their year of onset were recorded by chart review in neuropathologically diagnosed patients with PSP, Parkinsons's disease (PD), MSA parkinsonism and corticobasal degeneration from four European brain banks. Fulfilment of the clinical diagnostic criteria was verified for each year after disease onset and for the final antemortem record. We analyzed 98 PSP patients and 46 disease controls. The NINDS‐SPSP “probable” criteria yielded shorter time to diagnosis, slightly higher specificity and positive predictive value (PPV), and similar sensitivity, compared with the NNIPPS criteria. Unexpectedly, the NINDS‐SPSP “possible” criteria yielded the lowest sensitivity, specificity, and PPV. A combination of NINDS‐SPSP possible and probable criteria yielded the highest sensitivity. We suggest that the NINDS‐SPSP probable criteria might be preferred for recruitment of patients for clinical trials, where an early and specific diagnosis is important. For routine clinical care, where high sensitivity is crucial, a combination of NINDS possible and probable criteria might be preferred. © 2013 Movement Disorder Society     

Oligodendroglial lineage cells express nuclear p57kip2 in multiple sclerosis lesions

Impaired remyelination in multiple sclerosis (MS) might be due to the failure of oligodendrocyte precursor cells (OPC) to differentiate into myelinating oligodendrocytes. Animal experimental data have shown that p57kip2 inhibits oligodendroglial differentiation, indicating that this factor could contribute to remyelination failure. This study investigates oligodendroglial p57kip2 expression and its association with remyelination in MS lesions. To analyze the potential association of p57kip2 expression with human oligodendroglial maturation, double immunofluorescence staining was performed on brain tissue from 30 MS patients and 20 controls. Anti‐p57kip2 antibody was combined with either anti‐Nogo‐A to label mature oligodendrocytes or anti‐Olig2 antibodies to identify immature OPCs. We evaluated MS lesions with or without remyelination, the periplaque white matter (PPWM) as well as control white matter (WM). p57kip2‐expressing cells were assessed and correlated with the extent of remyelination. Most Nogo‐A‐positive oligodendrocytes (range, 87–98%) and all Olig2^strong‐positive OPCs expressed p57kip2 in MS lesions, in the PPWM and in control WM. p57kip2 expression in oligodendrocytes and OPCs were similar in MS lesions with remyelination compared to MS lesions lacking remyelination. Interestingly, all oligodendroglial lineage cells showed nuclear p57kip2 expression only, with mature oligodendrocytes expressing p57kip2 at low or intermediate levels and OPCs featuring strong expression levels, indicating that this factor may be dynamically expressed during maturation processes. Therefore, p57kip2 appears to be widely expressed in the human oligodendroglial lineage, and potential beneficial effects on remyelination in the MS brain are not based on subcellular p57kip2 localization shifts, as suggested by previous animal experiments. GLIA 2013;61:1250–1260     

Influence of ANKK1 and DRD2 polymorphisms in response to haloperidol

The present study explores whether ankyrin repeat and kinase domain containing 1 (ANKK1) and dopamine receptor D2 (DRD2) variants could predict efficacy and tolerability of haloperidol in the treatment of psychotic patients. We also attempted to replicate findings in a group of schizophrenic patients from the Clinical Antipsychotic Trials in Intervention Effectiveness (CATIE) study. Eighty-eight acutely psychotic patients were genotyped for 9 ANKK1 and 27 DRD2 SNPs. Treatment efficacy and tolerability were assessed using the Positive and Negative Symptoms Scale and the Udvalg for Kliniske Undersogelser side effects rating scales, respectively. Multivariate analyses were employed to test possible influences of single-nucleotide polymorphisms on clinical and safety variables. Analysis of haplotypes was also performed. Outcomes in the replication sample were response versus nonresponse and the presence versus absence of motor side effects at 1 month of treatment. rs2242592 within ANKK1 gene and rs1124493 within DRD2 gene were associated with clinical improvement (p = 0.008 and p = 0.001, respectively). Results were confirmed in the allelic analysis. Three haplotype blocks, one among ANKK1 and two among DRD2 gene were associated with better clinical improvement. Our results were not replicated in the CATIE sample, although rs11604671, which is in strong linkage disequilibrium with rs2242592, was associated with response in the replication sample. Our findings support a possible role of ANKK1 and DRD2 variability on haloperidol efficacy. However, due to the discrepancies between the results in the two samples, our results need further validation.     

The role of metabolism in the developmental toxicity of polycyclic aromatic hydrocarbon-containing extracts of petroleum substances

In vitro assays presently used for prenatal developmental toxicity (PDT) testing only assess the embryotoxic potential of parent substances and not that of potentially embryotoxic metabolites. Here we combined a biotransformation system, using hamster liver microsomes, with the ES-D3 cell differentiation assay of the embryonic stem cell test (EST) to compare the in vitro PDT potency of two 5-ring polycyclic aromatic hydrocarbons (PAHs), benzo[a]pyrene (BaP) and dibenz[a,h]anthracene (DBA), and dimethyl sulfoxide extracts from five PAH-containing petroleum substances (PS) and a gas-to-liquid base oil (GTLb), with and without bioactivation. In the absence of bioactivation, DBA, but not BaP, inhibited the differentiation of ES-D3 cells into beating cardiomyocytes in a concentration-dependent manner. Upon bioactivation, BaP induced in vitro PDT, while its major metabolite 3-hydroxybenzo[a]pyrene was shown to be active in the EST as well. This means BaP needs biotransformation to exert its embryotoxic effects. GTLb extracts tested negative in the EST, with and without bioactivation. The PS-induced PDT in the EST was not substantially changed following bioactivation, implying that metabolism may not play a crucial role for the PS extracts under study to exert the in vitro PDT effects. Altogether, these results indicate that although some PAH require bioactivation to induce PDT, some do not and this latter appears to hold for the (majority of) the PS constituents responsible for the in vitro PDT of these complex substances.     

Changes in ADC and T2-weighted MRI-derived radiomic features in patients treated with focal salvage HDR prostate brachytherapy for local recurrence after previous external-beam radiotherapy

PurposeTo explore the changes in T2-weighted (T2w) and apparent diffusion coefficient (ADC) magnetic resonance imaging -derived radiomic features of the gross tumor volume (GTV) from focal salvage high-dose-rate prostate brachytherapy (HDRB) and to correlate with clinical parameters.Materials and MethodsEligible patients included those with biopsy-confirmed local recurrence that correlated with MRI (T2w, ADC). Patients received 27 Gy in 2 fractions separated by 1 week to a quadrant consisting of the GTV. The MRI was repeated 1 year after HDRB. GTVs, planning target volumes, and normal prostate tissue control volumes were identified on the pre- and post-HDRB MRIs. Radiomic features from each GTV were extracted, and principle component analysis identified features with the highest variance.ResultsPre- and post-HDRB MRIs were obtained from 14 trial patients. Principle component analysis showed that 18 and 17 features contributed to 93% and 86% of the variance observed in the T2w and ADC data, respectively. Sixteen T2w features and 1 ADC GTV feature were different from the control volumes in the pre-HDRB images (p < 0.05). Ten T2w and 7 ADC GTV post-HDRB features were different from those of pre-HDRB (p < 0.05).ConclusionsExploratory analysis reveals several radiomic features in the T2w and ADC image GTVs that distinguish the GTV from healthy prostate tissue and change significantly after salvage HDRB.