A metabolomic study of cervical dystonia.

INTRODUCTION: Cervical dystonia is the most common of the adult-onset focal dystonias. Most cases are idiopathic. The current view is that cervical dystonia may be caused by some combination of genetic and environmental factors. Genetic contributions have been studied extensively, but there are few studies of other factors. We conducted an exploratory metabolomics analysis of cervical dystonia to identify potentially abnormal metabolites or altered biological pathways. METHODS: Plasma samples from 100 cases with idiopathic cervical dystonia and 100 controls were compared using liquid chromatography coupled with mass spectrometry-based metabolomics. RESULTS: A total of 7346 metabolic features remained after quality control, and up to 289 demonstrated significant differences between cases and controls, depending on statistical criteria chosen. Pathway analysis revealed 9 biological processes to be significantly associated at p < 0.05, 5 pathways were related to carbohydrate metabolism, 3 pathways were related to lipid metabolism. CONCLUSION: This is the first large scale metabolomics study for any type of dystonia. The results may provide potential novel insights into the biology of cervical dystonia.

The Effect of Escitalopram on Central Serotonergic and Dopaminergic Systems in Patients with Cervical Dystonia, and Its Relationship with Clinical Treatment Effects: A Double-Blind Placebo-Controlled Trial.

Purpose: The pathophysiology of cervical dystonia (CD) is thought to be related to changes in dopamine and serotonin levels in the brain. We performed a double-blind trial with escitalopram (selective serotonin reuptake inhibitor; SSRI) in patients with CD. Here, we report on changes in dopamine D2/3 receptor (D2/3R), dopamine transporter (DAT) and serotonin transporter (SERT) binding potential (BPND) after a six-week treatment course with escitalopram or placebo. Methods: CD patients had [123I]FP-CIT SPECT (I-123 fluoropropyl carbomethoxy-3 beta-(4-iodophenyltropane) single-photon emission computed tomography) scans, to quantify extrastriatal SERT and striatal DAT, and [123I]IBZM SPECT (I-123 iodobenzamide SPECT) scans to quantify striatal D2/3R BPND before and after six weeks of treatment with either escitalopram or placebo. Treatment effect was evaluated with the Clinical Global Impression scale for dystonia, jerks and psychiatric symptoms, both by physicians and patients. Results: In both patients treated with escitalopram and placebo there were no significant differences after treatment in SERT, DAT or D2/3R BPND. Comparing scans after treatment with escitalopram (n = 8) to placebo (n = 8) showed a trend (p = 0.13) towards lower extrastriatal SERT BPND in the SSRI group (median SERT occupancy of 64.6%). After treatment with escitalopram, patients who reported a positive effect on dystonia or psychiatric symptoms had significantly higher SERT occupancy compared to patients who did not experience an effect. Conclusion: Higher extrastriatal SERT occupancy after treatment with escitalopram is associated with a trend towards a positive subjective effect on dystonia and psychiatric symptoms in CD patients.

Expression of Bax/Bcl-2, TGF-ß1, and Type III Collagen Fiber in Congenital Muscular Torticollis.

BACKGROUND This study investigated the expression of Bax/Bcl-2, TGF-ß1 and type III collagen fiber in sternocleidomastoid of congenital muscular torticollis (CMT), and explored the possible mechanisms of fibrosis in sternocleidomastoid of CMT. MATERIAL AND METHODS The localization and expression of Bax, Bcl-2, TGF-ß1, and type III collagen were detected in the control group and experimental group by using immunohistochemical staining method. The RT-PCR assay was used to measure the expression of TGF-ß1 in the control group and experimental group. RESULTS HE staining results showed that the collagen fiber in the experimental group had more abundant hyperplasia compared to the control group (p<0.05). Immunohistochemical staining results showed that the expression of Bax, Bax/Bcl-2, TGF-ß1, and type III collagen in the experimental group was significantly increased compared to the control group (p<0.01). There were positive correlations between expression of Bax/Bcl-2 and TGF-b1, and between expression of TGF-ß1 and type III collagen fiber (p<0.05, r=0.32 and 0.83, respectively). The RT-PCR results showed that the expression of TGF-ß1 mRNA was also significantly elevated in the experimental group compared to the control group (p<0.05). CONCLUSIONS Increased muscular apoptosis may aggravate the formation of muscular fibrosis, which may be involved in the pathogenesis of sternocleidomastoid of CMT.

The relationship between the dopaminergic system and depressive symptoms in cervical dystonia.

PURPOSE: Cervical dystonia (CD) is associated with tremor/jerks (50%) and psychiatric complaints (17-70%). The dopaminergic system has been implicated in the pathophysiology of CD in animal and imaging studies. Dopamine may be related to the motor as well as non-motor symptoms of CD. CD is associated with reduced striatal dopamine D2/3 (D2/3) receptor and increased dopamine transporter (DAT) binding. There are differences in the dopamine system between CD patients with and without jerks/tremor and psychiatric symptoms. METHODS: Patients with CD and healthy controls underwent neurological and psychiatric examinations. Striatal DAT and D2/3 receptor binding were assessed using [123I]FP-CIT and [123I]IBZM SPECT, respectively. The ratio of specific striatal to non-specific binding (binding potential; BPND) was the outcome measure. RESULTS: Twenty-seven patients with CD and 15 matched controls were included. Nineteen percent of patients fulfilled the criteria for a depression. Striatal DAT BPND was significantly lower in depressed versus non-depressed CD patients. Higher DAT BPND correlated significantly with higher scores on the Unified Myoclonus Rating Scale (UMRS). The striatal D2/3 receptor BPND in CD patients showed a trend towards lower binding compared to controls. The D2/3 BPND was significantly lower in depressed versus non-depressed CD patients. A significant correlation between DAT and D2/3R BPND was found in both in patients and controls. CONCLUSIONS: Alterations of striatal DAT and D2/3 receptor binding in CD patients are related mainly to depression. DAT BPND correlates significantly with scores on the UMRS, suggesting a role for dopamine in the pathophysiology of tremor/jerks in CD.

Quantitative assessment of brain iron by R2* relaxometry in patients with cervical dystonia.

BACKGROUND: The pathophysiology of cervical dystonia is poorly understood. Increased brain iron deposition has been described in different movement disorders. Our aim was to investigate brain iron content in patients with cervical dystonia, using R2* relaxation rate, a validated MRI marker of brain iron level. METHODS: Twelve female patients with primary focal cervical dystonia (mean age: 45.4 ± 8.0 years) and 12 age-matched healthy female subjects (mean age: 45.0 ± 8.0 years) underwent 3T MRI to obtain regional R2* relaxation rates of the thalamus, caudate nucleus, putamen, and globus pallidus (GP). Regions of interest were delineated automatically on T1-weighted MRIs. RESULTS: R2* values in the putamen were positively correlated with age. Patients with cervical dystonia showed elevated R2* values in the GP. CONCLUSIONS: This pilot study provides the first quantitative support for increased brain iron deposition in cervical dystonia. Further studies are needed to explore the implications of this finding.

Integrative analysis of congenital muscular torticollis: from gene expression to clinical significance.

BACKGROUND: Congenital muscular torticollis (CMT) is characterized by thickening and/or tightness of the unilateral sternocleidomastoid muscle (SCM), ending up with torticollis. Our aim was to identify differentially expressed genes (DEGs) and novel protein interaction network modules of CMT, and to discover the relationship between gene expressions and clinical severity of CMT. RESULTS: Twenty-eight sternocleidomastoid muscles (SCMs) from 23 subjects with CMT and 5 SCMs without CMT were allocated for microarray, MRI, or immunohistochemical studies. We first identified 269 genes as the DEGs in CMT. Gene ontology enrichment analysis revealed that the main function of the DEGs is for extracellular region part during developmental processes. Five CMT-related protein network modules were identified, which showed that the important pathway is fibrosis related with collagen and elastin fibrillogenesis with an evidence of DNA repair mechanism. Interestingly, the expression levels of the 8 DEGs called CMT signature genes whose mRNA expression was double-confirmed by quantitative real time PCR showed good correlation with the severity of CMT which was measured with the pre-operational MRI images (R2 ranging from 0.82 to 0.21). Moreover, the protein expressions of ELN, ASPN and CHD3 which were identified from the CMT-related protein network modules demonstrated the differential expression between the CMT and normal SCM. CONCLUSIONS: We here provided an integrative analysis of CMT from gene expression to clinical significance, which showed good correlation with clinical severity of CMT. Furthermore, the CMT-related protein network modules were identified, which provided more in-depth understanding of pathophysiology of CMT.

Mutations in ANO3 cause dominant craniocervical dystonia: ion channel implicated in pathogenesis.

In this study, we combined linkage analysis with whole-exome sequencing of two individuals to identify candidate causal variants in a moderately-sized UK kindred exhibiting autosomal-dominant inheritance of craniocervical dystonia. Subsequent screening of these candidate causal variants in a large number of familial and sporadic cases of cervical dystonia led to the identification of a total of six putatively pathogenic mutations in ANO3, a gene encoding a predicted Ca(2+)-gated chloride channel that we show to be highly expressed in the striatum. Functional studies using Ca(2+) imaging in case and control fibroblasts demonstrated clear abnormalities in endoplasmic-reticulum-dependent Ca(2+) signaling. We conclude that mutations in ANO3 are a cause of autosomal-dominant craniocervical dystonia. The locus DYT23 has been reserved as a synonym for this gene. The implication of an ion channel in the pathogenesis of dystonia provides insights into an alternative mechanism that opens fresh avenues for further research.

Xeomin in the treatment of cervical dystonia.

BACKGROUND AND PURPOSE: Botulinum toxin type A (BoNT/A) is a highly effective and well-tolerated treatment for focal dystonias. The BoNT/A in Botox and Dysport is part of a high-molecular-weight complex that contains hemagglutinins and other non-toxic proteins, whilst Xeomin is a highly purified BoNT/A free of such complexing proteins. In the largest controlled study of BoNT/A published to date (Neurology 2005; 64: 1949), it was demonstrated that Xeomin is non-inferior to Botox and has 1:1 efficacy in the treatment of cervical dystonia. A possible limitation of continued BoNT/A treatment is antibody development. Based on its physiochemical properties and toxicological evidence, Xeomin is expected to have a reduced incidence of non-responders after long-term treatment compared with other marketed BoNT/A products. METHODS AND RESULTS: In our ongoing open-label study, 100 patients suffering from cervical dystonia are continuously treated with Xeomin; 50 patients were treated de novo, the remaining patients had been previously treated with Botox, Dysport or NeuroBloc/Myobloc. All patients showed negative results in antibody testing at the beginning of Xeomin treatment. During continuous treatment with Xeomin up to 2 years, patients continued to respond well to Xeomin treatment. CONCLUSION: The treatment was well tolerated and no patient has developed neutralizing antibodies as measured using the sensitive mouse hemidiaphragma assay within these first 2 years.

Diminished striatal [123I]iodobenzovesamicol binding in idiopathic cervical dystonia.

Striatal dysfunction is thought to underlie many dystonias. We used [(123)I]iodobenzovesamicol single-photon emission computed tomography imaging to determine the density of cholinergic terminals in the striatum and other brain regions in 13 subjects with idiopathic cervical dystonia. Striatal [(131)I]iodobenzovesamicol binding was reduced. These results support a role for striatal dysfunction in idiopathic dystonias and suggest diminished striatal cholinergic interneuron density in cervical dystonia.

Proton MR spectroscopy in idiopathic spasmodic torticollis.

Single-voxel proton magnetic resonance spectroscopy (1H-MRS), localised to the basal ganglia, was used to determine changes in metabolite levels in idiopathic spasmodic torticollis (IST). We examined nine patients and 13 healthy subjects. The mean values (+/- SD) of peak area ratios were: IST: N-acetyl-aspartate (NAA)/choline-containing compounds (Cho) 1.79 +/- 0.39, NAA/creatine and phosphocreatine compounds (Cr) 1.61 +/- 0.38, Cho/Cr 0.91 +/- 0.19; controls: NAA/Cho 2.07 +/- 0.35, NAA/ Cr 1.82 +/- 0.31, Cho/Cr 0.89 +/- 0.12. Statistical analysis showed that NAA/Cho and NAA/Cr were significantly lower in patients than in controls (P = 0.0304 and 0.0431, respectively). These results indicate a reduction in NAA, and suggest striatal involvement in the pathogenesis IST.

Botulinum toxin antibody testing: comparison between the immunoprecipitation assay and the mouse diaphragm assay.

Antibodies against botulinum toxin (BT) are currently best detected by the mouse diaphragm assay (MDA). Nevertheless, the MDA still has disadvantages, so that an immunoprecipitation assay (IPA) was introduced recently. We sought to compare the results of both tests. 33 samples from patients with cervical dystonia and complete or partial BT therapy failure underwent blinded simultaneous IPA and MDA testing. 27 (82%) samples showed concordant results, 17 (52%) being positive and 10 (30%) negative for both IPA and MDA resulting in a significant association of the dichotomous test results (Fisher's exact test, p < 0.01). The other six samples (18%) showed discordant results, all being IPA-negative and MDA-positive. This excess of MDA-positive results was also significant (Sign rank test, p = 0.03). IPA and MDA results showed a very strong and significant qualitative and quantitative association. The IPA seems to be less sensitive than the MDA for detection of low BT-AB titres, but the clinical relevance of this still needs to be established. Since the IPA is simpler, faster and cheaper than the MDA and avoids sacrifice of animals, it could become the preferred BT-AB test.

Evidence for disturbances of copper metabolism in dystonia: from the image towards a new concept.

The pathogenesis of idiopathic adult onset dystonia (ID) is still unclear. Although neuropathologic studies did not reveal consistent abnormalities, electrophysiologic and neuroimaging findings point toward a disinhibition and overactivity of the frontal motor cortical areas caused by an altered basal ganglia outflow. The lentiform nuclei are assumed to play a major role in this scenario. Recent neurochemical analysis of brain tissue stimulated by transcranial ultrasound studies demonstrated an increased copper content of the lentiform nuclei in patients with ID. The shift of brain copper level may substantially influence neuronal activity causing a reduced inhibitory output from the lentiform nuclei to the motor cortex. The reason for the presumably altered copper metabolism is not clear, but preliminary findings suggest that reduced levels of the Menkes protein, a membrane ATPase exporting copper out of the cells, may be implicated. Disturbances of brain copper metabolism may explain various phenomena of ID; however, it needs to be determined whether these observations represent the basic pathogenetic mechanism of ID or reflect another as yet unidentified pathologic process.

Localized proton NMR spectroscopy in the striatum of patients with idiopathic spasmodic torticollis.

Single voxel proton spectroscopy was used to study brain metabolism in idiopathic spasmodic torticollis. Peak metabolite ratios in long echo time (135 ms) spectra were evaluated in the basal ganglia of 16 patients (29-65 years). Eight of them were untreated; the other eight were examined 4-6 weeks after administration of botulinum toxin type A. As compared with 60 control spectra, patients showed a significant, therapy-resistant decrease in N-acetyl-L-aspartate (NAA)/choline (Cho). NAA/creatine (Cr) and Cho/Cr were close to normal in the post-treatment group but significantly reduced in untreated patients. This result is consistent with the hypothesis that striatal Cr is reversibly elevated in chronic muscle stimulation. The right and left striatum were affected to the same extent.

Cerebral glucose metabolism in patients with spasmodic torticollis.

The pathophysiology of spasmodic torticollis is not clear. Basal ganglia dysfunction has been suggested to underlie this clinical syndrome. We studied resting cerebral glucose metabolism in 10 spasmodic torticollis patients and 10 healthy controls by using positron-emission tomography and [18F]2-fluoro-2-deoxy-D-glucose. Statistical parametric mapping (SPM95) was used to compare both groups on a pixel-by-pixel basis. Torticollis patients showed a significantly higher glucose metabolism bilaterally in the lentiform nucleus (p < 0.005). Analyses performed using normalization of regional to global glucose metabolism confirmed this finding (controls, 1.26 +/- 0.06, and patients, 1.35 +/- 0.06; p < 0.01). The torticollis score did not correlate with glucose metabolism, nor did disease duration or side of chin direction. Our results indicate that the lentiform nucleus plays a predominant role in the pathophysiology of idiopathic spasmodic torticollis.

Dopamine D2 receptor imaging with iodine-123-iodobenzamide SPECT in idiopathic rotational torticollis.

UNLABELLED: The cause of idiopathic rotational torticollis (IRT) is not completely understood to date. However, basal ganglia are believed to be involved in the pathophysiology of IRT. To elucidate this disorder further, the value of iodobenzamide (IBZM) SPECT was studied for the evaluation of striatal dopamine D2 receptors in these patients. METHODS: Striatal dopamine D2 receptor density was assessed in 10 patients with IRT using 123I-IBZM SPECT. The images were interpreted by a nuclear medicine physician initially to determine IBZM binding within the striatum and the cerebellum and, secondly, interstriatal IBZM binding. The results were correlated with the clinical parameters of the patients and compared with the results obtained from normal controls. RESULTS: No difference was found in average, specific striatal IBZM binding (basal ganglia/cerebellum ratio) between patients and controls. However, interstriatal analysis of IBZM binding revealed a significantly higher binding in the striatum contralateral to the direction of the torticollis (p = 0.026, by chi-square test). CONCLUSION: It was concluded that the striatal dopamine D2 receptor status is altered in patients with IRT.

Striatal [11C]-N-methyl-spiperone binding in patients with focal dystonia (torticollis) using positron emission tomography.

Specific binding of [11C]-N-methyl-spiperone to striatal dopamine D2 receptors was assessed using positron emission tomography (PET) in 6 patients with adult-onset focal dystonia (predominantly spasmodic torticollis) and in 5 healthy subjects. No significant difference in average specific striatal tracer uptake between patients and healthy subjects was found. However, in the 5 patients showing lateralisation of clinical signs a trend to higher striatal tracer uptake in the contralateral hemisphere was observed.

Increased striatal 18F-dopa uptake and normal glucose metabolism in idiopathic dystonia syndrome.

Striatal 18F-Dopa uptake and glucose metabolism were studied by positron emission tomography with 6-L-[18F]fluorodopa and [18F]fluorodeoxyglucose, respectively, in 8 patients with idiopathic dystonia. Patients with abnormal findings on the brain CT and MRI were excluded from this study. The clinical diagnosis consisted of torsion dystonia in 3 patients, focal dystonia limited in the arm in 3 and cervical dystonia (spasmodic torticollis) in 2. The 18F-Dopa uptake, corrected by nonspecific retention in the cerebellum, at 120 min post-administration was evaluated, and increased 18F-Dopa uptake in the putamen and in the caudate head was observed in the patients with idiopathic dystonia compared to the normal controls. The striatal glucose metabolism in the patients with idiopathic dystonia showed no difference with the normal controls. These findings suggest that pathogenetic mechanism of idiopathic dystonia involves increased presynaptic activity of the dopaminergic system in the striatum.

Positron emission tomography demonstrates frontal cortex and basal ganglia hypometabolism in dystonia.

We studied 15 dystonic patients with positron emission tomography (PET) and (18F)-2-fluoro-2-deoxy-D-glucose (FDG). The group comprised patients with focal (n = 5), multifocal (n = 1), and generalized (n = 4) dystonia as well as patients with hemidystonia (n = 5). The age at onset was during childhood in four, during adolescence in two, and during adulthood in nine of the subjects. In dystonic patients, global cerebral glucose metabolism was unaltered when compared with normal controls, whereas the pattern of regional cerebral metabolic rate for glucose (rCMR[Glu]) was significantly different (p = 0.0001). rCMR(Glu) was significantly decreased in the caudate and lentiform nucleus and in the frontal projection field of the mediodorsal thalamic nucleus. The study confirms the concept that dystonia is caused by impaired connections between the basal ganglia, the thalamus, and frontal association areas.

[Spastic torticollis]. / Spasticheskaia krivosheia.

Fifty-seven cases of spastic torticollis are reported, and its etiologic factors, including stressful situations, are analyzed. Plasma serotonin measurements have added new insight into pathogenetic mechanisms of the condition. The range of "reflex" spastic torticollis has been limited on the basis of biochemical and EMG findings. Fairly high incidence of attendant extrapyramidal symptoms and their polymorphism are pointed out, and, the need for a differential approach to the treatment of spastic torticollis being emphasized, a schedule of combined treatment, incorporating eglonyl and amitriptyline, is proposed for clonic-tonic torticollis.