Mariachiara Sensi

Botulinum Toxin type A reduces capsaicin-evoked pain and neurogenic vasodilatation in human skin

Abstract The effect of Botulinum Toxin type A (BoNT/A) on pain and neurogenic vasodilatation induced by application to the human skin of thermal stimuli and capsaicin was evaluated in a double blind study. A capsaicin cream (0.5 ml of a 0.075%) was applied to the skin of both forearms of eighteen subjects randomly pretreated with either BoNT/A (Botox®) or 0.9% saline (NS). Capsaicin was applied to a skin area either inside (protocol A) or adjacent to the BoNT/A treated area (protocol B). Pre‐treatment with BoNT/A did not affect thermal‐specific and thermal‐pain thresholds (by quantitative sensory testing). However, capsaicin‐induced pain sensation (by a visual analogue scale), flare area (by acetate sheet) and changes in cutaneous blood flow (CBF, by laser Doppler flowmetry) were reduced when capsaicin was administered inside (protocol A) the BoNT/A treated area. In Protocol B, capsaicin‐induced pain was unchanged, and capsaicin‐induced flare/increase in CBF were reduced only in the area treated with BoNT/A, but not in the BoNT/A untreated area. Results indicate that (i) BoNT/A reduces capsaicin‐induced pain and neurogenic vasodilatation without affecting the transmission of thermal and thermal‐pain modalities; (ii) reduction in capsaicin‐induced pain occurs only if capsaicin is administered into the BoNT/A pretreated area; (iii) reduction in neurogenic vasodilatation by BoNT/A does not contribute to its analgesic action. BoNT/A could be tested for the treatment of conditions characterised by neurogenic inflammation and inflammatory pain.

Validation of the Italian version of the Movement Disorder Society--Unified Parkinson's Disease Rating Scale.

The Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) has been available in English since 2008. As part of this process, the MDS-UPDRS organizing team developed guidelines for development of official non-English translations. We present here the formal process for completing officially approved non-English versions of the MDS-UPDRS and specifically focus on the first of these versions in Italian. The MDS-UPDRS was translated into Italian and tested in 377 native-Italian speaking PD patients. Confirmatory and exploratory factor analyses determined whether the factor structure for the English-language MDS-UPDRS could be confirmed in data collected using the Italian translation. To be designated an ‘Official MDS translation,’ the Comparative Fit Index (CFI) had to be ≥0.90 relative to the English-language version. For all four parts of the Italian MDS-UPDRS, the CFI, in comparison with the English-language data, was ≥0.94. Exploratory factor analyses revealed some differences between the two datasets, however these differences were considered to be within an acceptable range. The Italian version of the MDS-UPDRS reaches the criterion to be designated as an Official Translation and is now available for use. This protocol will serve as outline for further validation of this in multiple languages.

A computational modelling approach to investigate different targets in deep brain stimulation for Parkinson’s disease

We investigated by a computational model of the basal ganglia the different network effects of deep brain stimulation (DBS) for Parkinson’s disease (PD) in different target sites in the subthalamic nucleus (STN), the globus pallidus pars interna (GPi), and the globus pallidus pars externa (GPe). A cellular-based model of the basal ganglia system (BGS), based on the model proposed by Rubin and Terman (J Comput Neurosci 16:211–235, 2004), was developed. The original Rubin and Terman model was able to reproduce both the physiological and pathological activities of STN, GPi, GPe and thalamo-cortical (TC) relay cells. In the present study, we introduced a representation of the direct pathway of the BGS, allowing a more complete framework to simulate DBS and to interpret its network effects in the BGS. Our results suggest that DBS in the STN could functionally restore the TC relay activity, while DBS in the GPe and in the GPi could functionally over-activate and inhibit it, respectively. Our results are consistent with the experimental and the clinical evidences on the network effects of DBS.

Brain Interstitial Nociceptin/Orphanin FQ Levels are Elevated in Parkinson's Disease

Expression and release of nociceptin/orphanin FQ (N/OFQ) are elevated in the substantia nigra reticulata of 6‐hydroxydopamine‐hemilesioned rats, suggesting a pathogenic role for N/OFQ in Parkinsons disease. In this study, we investigated whether elevation of N/OFQ expression in 6‐hydroxydopamine‐hemilesioned rats selectively occurs in substantia nigra and whether hypomotility following acute haloperidol administration is accompanied by a rise in nigral N/OFQ levels. Moreover, to prove a link between N/OFQ and idiopathic Parkinsons disease in humans, we measured N/OFQ levels in the cerebrospinal fluid of parkinsonian patients undergoing surgery for deep brain stimulation. In situ hybridization demonstrated that dopamine depletion was associated with increase of N/OFQ expression in substantia nigra (compacta +160%, reticulata +105%) and subthalamic nucleus (+45%), as well as reduction in caudate putamen (−20%). No change was observed in globus pallidus, nucleus accumbens, thalamus, and motor cortex. Microdialysis coupled to the bar test allowed to demonstrate that acute administration of haloperidol (0.8 and 3 mg/kg) increased nigral N/OFQ levels (maximally of +47% and +53%, respectively) in parallel with akinesia. A correlation with preclinical studies was found by analyzing N/OFQ levels in humans. Indeed, N/OFQ levels were found to be ∼3.5‐fold elevated in the cerebrospinal fluid of parkinsonian patients (148 fmol/ml) compared with nonparkinsonian neurologic controls (41 fmol/ml). These data represent the first clinical evidence linking N/OFQ to idiopathic Parkinsons disease in humans. They strengthen the pathogenic role of N/OFQ in the modulation of parkinsonism across species and provide a rationale for developing N/OFQ receptor antagonists as antiparkinsonian drugs.

Pallidal stimulation for segmental dystonia: Long term follow up of 11 consecutive patients†

Pallidal stimulation is a convincing and valid alternative for primary generalized dystonia refractory to medical therapy or botulinum toxin. However, the clinical outcome reported in literature is variable most likely because of heterogeneity DBS techniques employed and /or to clinical dystonic pattern of the patients who undergo surgery. In this study, we report the long term follow up of a homogeneous group of eleven subjects affected by segmental dystonia who were treated with bilateral stimulation of the Globus Pallidus pars interna (GPi) from the years 2000 to 2008. All the patients were evaluated, before surgery and at 6‐12‐24‐36 months after the treatment, in accordance with the Burke Fahn Marsden Dystonia Rating Scale (BFMDRS). Our study indicates that DBS promotes an early and significant improvement at 6 months with an even and a better outcome later on. The analysis of specific sub items of the BFMDRS revealed an earlier and striking benefit not only as far as segmental motor function of the limbs but also for the complex cranial functions like face, (eyes and mouth), speech and swallowing, differently from results reported in primary generalized dystonia. Deep Brain Stimulation of GPi should be considered a valid indication for both generalized and segmental dystonia when other therapies appear ineffective.

Emerging issues on selection criteria of levodopa carbidopa infusion therapy: considerations on outcome of 28 consecutive patients.

Many studies confirmed the efficacy and safety of continuous infusion of intrajejunal levodopa/carbidopa gel (CIILG) for advanced Parkinson’s disease (PD). Although this treatment is widely used, definite inclusion/exclusion criteria do not exist. In this prospective open-label study, we evaluated the long-term outcome in 28 consecutive patients and sought to detect any predictive factor to identify the best candidates for CIILG therapy. The assessment was carried out routinely at baseline, after 6 months and every year with UPDRS III–IV, FOG Questionnaire, non-motor symptoms scale, PD questionnaire (PDQ-8), cognitive and psychiatric status evaluation (MMSE, FAB, NPI) and caregiver’s quality of life. 17/28 patients reached the 24-month follow-up. A statistically significant beneficial effect was shown on motor complications in short- and long-term follow-up, also on axial symptoms like gait disturbances. A concomitant improvement in PDQ8 score was observed, with a parallel mild amelioration, but not significant, on Caregivers QoL. When classified according to their outcome on QoL, the only predictive positive factor was less severe at Neuropsychiatric Inventory (NPI) score at baseline. Considering the improvement in motor scores (duration of “off” period), the more advanced age was associated with a poorer outcome. Our results confirmed a sustained efficacy and safety in long-term follow-up and suggest that younger age at operation and absence or mild presence of psychiatric/behavioural symptoms could be considered valid predicting factors in selecting the best candidates for this efficacious therapy.

Switching from constant voltage to constant current in deep brain stimulation: A multicenter experience of mixed implants for movement disorders

For many years deep brain stimulation (DBS) devices relied only on voltage‐controlled stimulation (CV), but recently current‐controlled devices have been developed and approved for new implants as well as for replacement of CV devices after battery drain. Constant‐current (CC) stimulation has been demonstrated to be effective in new implanted parkinsonian and dystonic patients, but the effect of switching to CC therapy in patients chronically stimulated with CV implantable pulse generators (IPGs) has not been assessed. This report shows the results of a consecutive retrospective data collection performed at five Italian centers before and after replacement of constant‐voltage with constant‐current DBS devices, in order to verify the clinical efficacy and safety of this procedure.

The Contursi Family 20 Years Later: Intrafamilial Phenotypic Variability of the SNCA p.A53T Mutation

The SNCA/alpha-synuclein p.A53T mutation segregating in the Contursi kindred was the first mutation ever described in inherited Parkinson’s disease (PD). We directly examined 10 subjects (4 PD patients and 6 asymptomatic relatives) of a branch of the Contursi kindred. We also collected data on 11 members affected by history, through interviews and inspection of available medical records. Nine had died in the fourth to seventh decade diagnosed with PD (plus psychiatric features in 3), whereas 2 were reported to have severe psychiatric disturbances and were unavailable for examination. After obtaining ethics approval and written informed consent, all subjects underwent a complete neurological examination (see Video 1) and SNCA p.A53T mutation testing. The 4 PD patients (age, 42 6 9.8 years), and 2 unaffected individuals (age, 29.5 6 2.1 years) resulted as heterozygous for the mutation. Two affected (III:1, IV:1) and 2 unaffected (IV:2, IV:6) carriers also underwent extensive neuropsychological and psychiatric assessment, olfaction evaluation, and dopamine transporter imaging with single-photon emission computed tomography (DAT-SPECT); 3T brain MRI was performed in 3 subjects (III:1, IV:2, and IV:6; Fig. 1). Although the overall phenotype in the 4 patients was typical of SNCA-related PD with early, asymmetric onset, initial good response to dopaminergic therapy and early motor complications, a relevant variability was observed in the combination and severity of motor symptoms (partially responding to levodopa and DBS in III-9) and nonmotor features (Table 1). Age at onset varied from 26 to 48 years (mean, 32.7 6 10.5), with longer disease duration than previously reported (from 2 to 19 years; mean, 9.26 8.5). Cognitive deficits were present in all 4 patients, ranging from frank dementia in those with longer disease duration (III-8, III-9) to moderate cognitive impairment (III-1) or slight isolated executive dysfunction (IV-1) in those with a shorter one. Depression and anxiety were detected in 3 patients, behavioral disorders in 2, and dysautonomia in 2. Olfaction was impaired in both tested patients. Although the variable severity could depend on the different disease duration, the wide range of ages at onset among carriers of the same genetic mutation remains unexplained, suggesting the existence of yet unknown environmental, genetic, and/or epigenetic modifiers. Interestingly, 2 asymptomatic carriers, ages 31 and 28 years, were clinically unaffected. Their general cognitive functions were normal and they did not refer any sleep or mood disorder. However, the younger one (IV:2) presented an objective olfactory deficit and an abnormal DAT scan, suggesting an underlying, still subclinical, neurodegenerative process. The existence of SNCA mutation carriers who remain clinically asymptomatic at ages beyond the expected age of onset has been reported, implying reduced penetrance. However, our carriers were still younger than the latest age of onset in the family; therefore, any conclusion would be merely speculative and further clinical follow-up is necessary. In conclusion, our data further highlight the relevant intrafamilial phenotypic variability in carriers of the SNCA p.A53T mutation, suggesting a role for yet unknown genetic or environmental modifiers. Follow-up studies are encouraged to better define the clinical spectrum of PD caused by SNCA gene mutations.

The arginine growth hormone stimulation test in bradykinetic-rigid parkinsonisms.

The arginine growth hormone (GH) stimulation test differentiates the Parkinsonian variant of multiple system atrophy (MSA‐P) from idiopathic Parkinsons disease (PD). Our aim was to evaluate the accuracy of the arginine GH stimulation test in distinguishing between PSP, MSA‐P, and PD. We measured the GH response to arginine in serum samples of 26 MSA‐P, 23 PSP, and 26 PD patients, and in 80 healthy controls. We used ANOVA followed by the Bonferroni test to compare GH values and peaks among groups. We used receiver operating characteristic curve analysis to establish the arginine cut‐off level that best differentiated between MSA‐P, PSP, and PD. The GH peak was significantly lower (P < 0.01) in MSA‐P (1.46 ± 0.29 μg/L) than in both PD (8.74 ± 0.98 μg/L) and PSP (6.64 ± 0.82 μg/L) patients, and controls (8.59 ± 0.44 μg/L). Growth hormone peaked later in PSP patients than in PD patients and controls. At a cut‐off level of 4 μg/L, arginine test distinguished MSA‐P from PD with a sensitivity of 92% and a specificity of 96%, and MSA‐P from PSP with a sensitivity of 78% and a specificity of 96%. The GH response to arginine differentiates MSA‐P from PD and PSP with a good diagnostic accuracy. The neuroendocrine response to arginine of PSP patients differed from that of MSA‐P patients, but was not identical to that of normal controls and PD patients. Our results suggest that the impairment of the central mechanisms modulating GH release differs between PSP and MSA‐P.

PRKRA Mutation Causing Early-Onset Generalized Dystonia-Parkinsonism (DYT16) in an Italian Family

Dystonia syndromes are clinically and genetically heterogeneous. DYT16 is caused by mutations in the PRKRA gene, with 1 missense substitution (c.665C>T, p.Pro222Leu, rs121434410) observed in 5 of the 6 families previously reported. We report genetic and clinical investigations in an Italian kindred containing 3 brothers with childhood-onset generalized dystonia and mild parkinsonian signs. Their (deceased) maternal grandfather was reported to have similar disturbances (further details in the Supporting Information). Detailed methods are reported as Supporting Methods. We performed whole-exome sequencing (WES) in 1 patient (III:4), and genome-wide linkage, homozygosity, and haplotype analyses in the whole family. By WES, we identified the PRKRA c.665C>T mutation, which was confirmed by Sanger sequencing and segregates with the disease in the homozygous state (Fig. 1A). This mutation has a frequency of 0.01% in the Exome Aggregation Consortium database and is predicted to be deleterious by 2 of 6 in silico tools (Supporting Table 1). Genome-wide linkage analysis under autosomal recessive mode of inheritance yielded only 1 significant peak (LOD 3.72) on chromosome 2 (Fig. 1B). In this locus, a 4-Mb homozygous region is shared by the affected siblings (Fig. 1C), and besides the PRKRA mutation, no variants with MAF < 1% were identified by WES. Haplotype analysis (Fig. 1D) showed that our patients and those in the previously reported families with this PRKRA mutation, share a 0.5-Mb founder haplotype (Supporting Table 2). WES also revealed single heterozygous missense variants in DNAJC6 and GCH1 outside the significant linkage peak (Supporting Tables 4 and 5). We consider them to be likely incidental findings, unrelated to the disease. However, we cannot exclude that they play some role in the disease process, together with the primary homozygous PRKRA mutation. The phenotype of our patients overlaps that of previously reported DYT16 patients (Supporting Table 3). The 3 siblings developed childhood-onset generalized dystonia with mild parkinsonian signs. Detailed case reports and videotapes are provided (Supporting Information). The early clinical phases of their disorder have been previously reported. The disease has progressed slowly in all siblings, and in the last 10 years the clinical picture has remained substantially unchanged. At last examination (2015) the patients were suffering from a generalized dystonia with intrafamilial variability. Cranial and laryngeal dystonia are predominant in the older brother, whereas limb involvement is predominant in the younger siblings. All patients showed global slowness of movements and bradykinesia in the finger-tapping and foot-tapping test. Formal neuropsychological evaluations showed clear evidence of cognitive impairment in the 3 brothers, particularly in the tasks assessing executive functions (Supporting Information). Brain MRI was repeatedly unremarkable. L-Dopa treatment was ineffective, whereas clonazepam, anticholinergics, baclofen, and particularly zolpidem provided mild but short-lasting improvements in all brothers. One patient underwent deep brain stimulation of the globus pallidus internus with improvement of the cranial and limb dystonia still maintained 10 years after the procedure. This work contributes to the ongoing clinical and genetic characterization of DYT16. Screening of PRKRA is warranted in all patients with early-onset generalized dystonia, or dystoniaparkinsonism compatible with autosomal recessive inheritance.