Elena Salvatore

Grey matter loss in relapsing-remitting multiple sclerosis: a voxel-based morphometry study.

Global grey matter (GM) loss has been reported in multiple sclerosis (MS). We addressed the question of if and where GM loss is localized by means of optimized voxel-based morphometry, applied to MRI studies of 51 patients with clinically defined relapsing-remitting MS and 34 age-matched normal subjects, segmented into normal and abnormal brain tissues using a multiparametric approach. Segmented GM volumes were subsequently compared on a voxel-by-voxel basis to highlight regions of relative GM loss (P < 0.05, corrected for multiple comparisons at AnCova). Additionally, localized differences in brain asymmetry between the MS and the control groups were assessed by comparing on a voxel-by-voxel basis maps of GM differences between the two hemispheres (P < 0.05 corrected for multiple comparisons). In MS patients, GM volume was significantly decreased at the level of the left fronto-temporal cortex and precuneus, as well as of anterior cingulate gyrus and of caudate nuclei bilaterally. The only cortical region of significant GM loss in the right hemisphere was located in the postcentral area. Furthermore, GM loss regions were colocalized with increased GM asymmetries (Left < Right) in MS, confirming a preferential left-sided GM loss. Caudate atrophy correlated with lesion load, while no correlation between cortical regional GM loss and disease duration, clinical status or lesion load emerged. Our findings suggest that in RR-MS cortical GM reduction preferentially involves left fronto-temporal structures and deep GM, the latter correlating preferentially to global lesion load.

Brain white matter tracts degeneration in Friedreich ataxia. An in vivo MRI study using tract-based spatial statistics and voxel-based morphometry

BACKGROUND AND PURPOSE Neuropathological examination in Friedreich ataxia (FRDA) reveals neuronal loss in the gray matter (GM) nuclei and degeneration of the white matter (WM) tracts in the spinal cord, brainstem and cerebellum, while the cerebral hemispheres are substantially spared. Tract-based spatial statistics (TBSS) enables an unbiased whole-brain quantitative analysis of the fractional anisotropy (FA) and mean diffusivity (MD) of the brain WM tracts in vivo. PATIENTS AND METHODS We assessed with TBSS 14 patients with genetically confirmed FRDA and 14 age- and sex-matched healthy controls who were also examined with voxel-based morphometry (VBM) to assess regional atrophy of the GM and WM. RESULTS TBSS revealed decreased FA in the inferior and superior cerebellar peduncles and the corticospinal tracts in the medullary pyramis, in WM tracts of the right cerebellar hemisphere and in the right occipito-frontal and inferior longitudinal fasciculi. Increased MD was observed in the superior cerebellar peduncles, deep cerebellar WM, posterior limbs of the internal capsule and retrolenticular area, bilaterally, and in the WM underlying the left central sulcus. Decreased FA in the left superior cerebellar peduncle correlated with clinical severity. VBM showed small symmetric areas of loss of bulk of the peridentate WM which also correlated with clinical severity. CONCLUSIONS TBSS enables in vivo demonstration of degeneration of the brainstem and cerebellar WM tracts which neuropathological examination indicates to be specifically affected in FRDA. TBSS complements VBM and might be a more sensitive tool to detect WM structural changes in degenerative diseases of the CNS.

Brain white matter damage in SCA1 and SCA2. An in vivo study using voxel-based morphometry, histogram analysis of mean diffusivity and tract-based spatial statistics

BACKGROUND AND PURPOSE Neurodegeneration in spinocerebellar ataxia type 1(SCA1) and 2(SCA2) is associated with white matter(WM) damage. Voxel-Based Morphometry(VBM), histogram analysis of mean diffusivity(MD) and Tract-Based Spatial Statistics(TBSS) enable an in vivo quantitative analysis of WM volume and structure. We assessed with these 3 techniques the whole brain WM damage in SCA1 and SCA2. PATIENTS AND METHODS Ten patients with SCA1, 10 patients with SCA2 and 10 controls underwent MRI with acquisition of T1-weighted and diffusion tensor images. The results were correlated with severity of clinical deficit. RESULTS VBM showed atrophy of the brainstem and cerebellar WM without significant differences between SCA1 and SCA2. Focal atrophy of the cerebral subcortical WM was also present. Histogram analysis revealed increased MD in the brainstem and cerebellum in patients with SCA1 and SCA2 which in SCA2 was more pronounced and combined with mild increase of the MD in the cerebral hemispheres in SCA2. In SCA1 and SCA2 TBSS revealed decreased fractional anisotropy(FA) in the inferior, middle and superior cerebellar peduncles, pontine transverse fibres, medial and lateral lemnisci, spinothalamic tracts, corticospinal tracts and corpus callosum. The extent of tract changes was greater in SCA2 patients who also showed decreased FA in the short intracerebellar tracts. In both diseases VBM, histogram and TBSS results correlated with clinical severity. CONCLUSIONS Brain WM damage featuring a pontocerebeellar atrophy is similar in SCA1 and SCA2 but more pronounced in SCA2. In both diseases it correlates with severity of the clinical deficit.

Brain structural damage in Friedreich’s ataxia

Objective: Neuropathological descriptions of the brain in Friedreich’s ataxia (FRDA) were obtained before availability of the current molecular genetic tests for this disease. Voxel-based morphometry (VBM) enables an unbiased whole-brain quantitative analysis of differences in gray matter (GM) and white matter (WM) volume. Methods: Using VBM, we assessed the brain structural damage in 22 patients with genetically confirmed FRDA and 25 healthy controls. The results were correlated with the disease duration and the severity of the patients’ clinical deficits—evaluated using the International Cerebellar Ataxia Rating Scale and Inherited Ataxia Clinical Rating Scale. Results: In patients with FRDA, VBM showed a symmetrical volume loss in dorsal medulla, infero-medial portions of the cerebellar hemispheres, the rostral vermis and in the dentate region. No volume loss in cerebral hemispheres was observed. The atrophy of the cerebellum and medulla correlated with the severity of the clinical deficit and disease duration. Conclusions: In patients with FRDA, significant GM and WM loss was observed only in the cerebellum and dorsal medulla. These structural changes correlate with the severity of the clinical deficit and disease duration.

Relationship between simultaneously acquired resting-state regional cerebral glucose metabolism and functional MRI: A PET/MR hybrid scanner study

Recently introduced hybrid PET/MR scanners provide the opportunity to measure simultaneously, and in direct spatial correspondence, both metabolic demand and functional activity of the brain, hence capturing complementary information on the brains physiological state. Here we exploited PET/MR simultaneous imaging to explore the relationship between the metabolic information provided by resting-state fluorodeoxyglucose-PET (FDG-PET) and fMRI (rs-fMRI) in neurologically healthy subjects. Regional homogeneity (ReHo), fractional amplitude of low frequency fluctuations (fALFF), and degree of centrality (DC) maps were generated from the rs-fMRI data in 23 subjects, and voxel-wise comparison to glucose uptake distribution provided by simultaneously acquired FDG-PET was performed. The mutual relationships among each couple of these four metrics were explored in terms of similarity, both of spatial distribution across the brain and the whole group, and voxel-wise across subjects, taking into account partial volume effects by adjusting for grey matter (GM) volume. Although a significant correlation between the spatial distribution of glucose uptake and rs-fMRI derived metrics was present, only a limited percentage of GM voxels correlated with PET across subjects. Moreover, the correlation between the spatial distributions of PET and rs-fMRI-derived metrics is spatially heterogeneous across both anatomic regions and functional networks, with lowest correlation strength in the limbic network (Spearman rho around -0.11 for DC), and strongest correlation for the default-mode network (up to 0.89 for ReHo and 0.86 for fALFF). Overall, ReHo and fALFF provided significantly higher correlation coefficients with PET (p=10(-8) and 10(-7), respectively) as compared to DC, while no significant differences were present between ReHo and fALFF. Local GM volume variations introduced a limited overestimation of the rs-fMRI to FDG correlation between the modalities under investigation through partial volume effects. These novel results provide the basis for future studies of alterations of the coupling between brain metabolism and functional connectivity in pathologic conditions.

Atorvastatin combined to interferon to verify the efficacy (ACTIVE) in relapsing-remitting active multiple sclerosis patients: A longitudinal controlled trial of combination therapy

A large body of evidence suggests that, besides their cholesterol-lowering effect, statins exert anti-inflammatory action. Consequently, statins may have therapeutic potential in immune-mediated disorders such as multiple sclerosis. Our objectives were to determine safety, tolerability and efficacy of low-dose atorvastatin plus high-dose interferon beta-1a in multiple sclerosis patients responding poorly to interferon beta-1a alone. Relapsing—remitting multiple sclerosis patients, aged 18—50 years, with contrast-enhanced lesions or relapses while on therapy with interferon beta-1a 44 µg (three times weekly) for 12 months, were randomized to combination therapy (interferon + atorvastatin 20 mg per day; group A) or interferon alone (group B) for 24 months. Patients underwent blood analysis and clinical assessment with the Expanded Disability Status Scale every 3 months, and brain gadolinium-enhanced magnetic resonance imaging at screening, and 12 and 24 months thereafter. Primary outcome measure was contrast-enhanced lesion number. Secondary outcome measures were number of relapses, EDSS variation and safety laboratory data. Forty-five patients were randomized to group A (n = 21) or B (n = 24). At 24 months, group A had significantly fewer contrast-enhanced lesions versus baseline (p = 0.007) and significantly fewer relapses versus the two pre-randomization years (p < 0.001). At survival analysis, the risk for a 1-point EDSS increase was slightly higher in group B than in group A (p = 0.053). Low-dose atorvastatin may be beneficial, as add-on therapy, in poor responders to high-dose interferon beta-1a alone.

Diffusion-weighted imaging in multiple system atrophy: A comparison between clinical subtypes†

Multiple system atrophy can be classified into two main types, a Parkinsonian (MSA‐P) and a cerebellar (MSA‐C) variant based on clinical presentation. We obtained diffusion‐weighted magnetic resonance imaging (DWI) in 9 MSA‐P and 12 MSA‐C patients and 11 controls, and correlated DWI changes with disease duration and severity. We found that Trace (D) values in the entire and anterior putamen were significantly higher in MSA‐P than in MSA‐C patients and controls, whereas Trace (D) values in the cerebellum and middle cerebellar peduncle (MCP) were significantly higher in MSA‐C than in MSA‐P patients and controls. Increased disease duration was significantly correlated with increased Trace (D) values in pons of MSA‐P patients, and in cerebellum and MCP of MSA‐C patients. Both UMSARS and UPDRS motor scores positively correlated with entire and posterior putaminal Trace (D) values in MSA‐P patients. The diffusivity changes parallel phenotypical and pathologic differences between MSA‐P and MSA‐C patients, suggesting that DWI is a feasible tool for in vivo evaluation of neurodegeneration in MSA. Based on our findings, Trace (D) measurements in the putamen and pons in MSA‐P patients and in the cerebellum and MCP in MSA‐C patients could serve as quantitative markers for microstructural damage in the course of disease.

A novel NKX2.1 mutation in a family with hypothyroidism and benign hereditary chorea.

BACKGROUND We studied a boy with congenital hypothyroidism, benign hereditary chorea, and respiratory distress. His mother and his grandfather were affected by hypothyroidism with a late onset and benign hereditary chorea. The aim of this study was to establish the genetic defects that cause that phenotype and study the molecular mechanisms of the pathology. METHODS NKX2.1, PAX8, NKX2.5, and TAZ genes were sequenced. RESULTS Direct sequencing of the NKX2.1 gene showed, in all the affected, a new heterozygous mutation from cytosine to adenine in the second base of the triplet encoding for the amino acid at position 145. The mutation (C609A) is responsible for a change from serine to a stop codon (S145X). We also demonstrated that the mutant protein is predominantly in the cytoplasm and unable to translocate into the nucleus. Of note, the S145X mutation produces variable phenotypes in the affected members of the family. No mutations have been identified in the NKX2.5, PAX8, and TAZ genes. CONCLUSIONS Our study extends the knowledge of the functional effect of NKX2.1 mutations and further highlights the complexities of genotype-phenotype correlation in the NKX2.1 deficiency syndromes.

Relative Frequencies of CAG Expansions in Spinocerebellar Ataxia and Dentatorubropallidoluysian Atrophy in 116 Italian Families

Two hundred and forty-eight patients from 116 Italian families with dominant ataxia were studied for CAG expansion within SCA1, 2, 3, 6, 7 (spinocerebellar ataxia) and DRPLA (dentatorubropallidoluysian atrophy) genes. Fifty-six percent of the families originated from Southern, 19% from Central and 25% from Northern Italy. SCA2 was the commonest mutation, accounting for 47% of the families, followed by SCA1 (24%), SCA6 (2%), SCA7 (2%) and DRPLA (1%). No SCA3 family was found. Twenty-four percent of the families carried a still unidentified mutation. When occurrence of mutations was evaluated according to the geographic origin, SCA1 was the commonest in Northern (72%), whereas SCA2 was prevalent (63%) in Southern Italy. The number of CAG repeats in SCA1 normal alleles was higher in Northern than in Central-Southern Italy.

Imaging of dopaminergic dysfunction with [123I]FP-CIT SPECT in early-onset parkin disease

Objective: To investigate whether the presence of parkin gene mutations is associated with different nigrostriatal impairment than other early-onset parkinsonism. Methods: Eighteen consecutive early-onset Parkinson disease (PD) patients (nine parkin and nine nonparkin patients) and six controls were studied with [123I]FP-CIT SPECT. Results: Parkin patients had longer disease duration (15 ± 9 vs 6 ± 2 years, p = 0.008) and higher Unified Parkinson’s Disease Rating Scale (UPDRS) motor score (35.8 ± 13.7 vs 22.8 ± 7.9, p = 0.025) than nonparkin patients. Caudate and putamen DAT density were reduced by 60% and 79% in parkin and by 43% and 70% in nonparkin patients. Multiple regression analysis showed that the UPDRS and the presence of parkin gene mutations, but not the disease duration, were significantly correlated with the striatal DAT density. Parkin patients showed a more symmetric DAT loss in both caudate and putamen as compared with nonparkin patients. Conclusions: Parkin-related disease may be associated with a higher degree of nigrostriatal impairment, independently of the clinical severity of the disease, and a more symmetric involvement as compared with non-parkin early-onset disease.