Disruption of the microbiota-gut-brain axis is a defining characteristic of the α-Gal A (-/0) mouse model of Fabry disease

Fabry disease (FD) is an X-linked metabolic disease caused by a deficiency in α-galactosidase A (α-Gal A) activity. This causes accumulation of glycosphingolipids, especially globotriaosylceramide (Gb3), in different cells and organs. Neuropathic pain and gastrointestinal (GI) symptoms, such as abdominal pain, nausea, diarrhea, constipation, and early satiety, are the most frequent symptoms reported by FD patients and severely affect their quality of life. It is generally accepted that Gb3 and lyso-Gb3 are involved in the symptoms; nevertheless, the origin of these symptoms is complex and multifactorial, and the exact mechanisms of pathogenesis are still poorly understood. Here, we used a murine model of FD, the male α-Gal A (-/0) mouse, to characterize functionality, behavior, and microbiota in an attempt to elucidate the microbiota-gut-brain axis at three different ages. We provided evidence of a diarrhea-like phenotype and visceral hypersensitivity in our FD model together with reduced locomotor activity and anxiety-like behavior. We also showed for the first time that symptomology was associated with early compositional and functional dysbiosis of the gut microbiota, paralleled by alterations in fecal short-chain fatty acid levels, which partly persisted with advancing age. Interestingly, most of the dysbiotic features suggested a disruption of gut homeostasis, possibly contributing to accelerated intestinal transit, visceral hypersensitivity, and impaired communication along the gut-brain axis.

Estimating motor unit numbers from a CMAP scan: Repeatability study on three muscles at 15 centres

OBJECTIVE

To assess the repeatability and suitability for multicentre studies of MScanFit motor unit number estimation (MUNE), which involves modelling compound muscle action potential (CMAP) scans.

METHODS

Fifteen groups in 9 countries recorded CMAP scans twice, 1-2 weeks apart in healthy subjects from abductor pollicis brevis (APB), abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. The original MScanFit program (MScanFit-1) was compared with a revised version (MScanFit-2), designed to accommodate different muscles and recording conditions by setting the minimal motor unit size as a function of maximum CMAP.

RESULTS

Complete sets of 6 recordings were obtained from 148 subjects. CMAP amplitudes differed significantly between centres for all muscles, and the same was true for MScanFit-1 MUNE. With MScanFit-2, MUNE differed less between centres but remained significantly different for APB. Coefficients of variation between repeats were 18.0% for ADM, 16.8% for APB, and 12.1% for TA.

CONCLUSIONS

It is recommended for multicentre studies to use MScanFit-2 for analysis. TA provided the least variable MUNE values between subjects and the most repeatable within subjects.

SIGNIFICANCE

MScanFit was primarily devised to model the discontinuities in CMAP scans in patients and is less suitable for healthy subjects with smooth scans.

A comparative blind study between skin biopsy and seed amplification assay to disclose pathological α-synuclein in RBD

To compare the diagnostic accuracy of the immunofluorescence (IF) technique and aSyn-seed amplification assay (aSyn-SAA) of skin and cerebrospinal fluid (CSF) in disclosing pathological α-syn in idiopathic idiopathic REM sleep behavior disorder (iRBD) as early phase of a synucleinopathy. We prospectively recruited 41 patients with iRBD and 40 matched clinical controls including RBD associated with type 1 Narcolepsy (RBD-NT1, 21 patients), iatrogenic causes (2 pt) or OSAS (6 pt) and 11 patients with peripheral neuropathies. IF from samples taken by skin biopsy and aSyn-SAA from skin and CSF samples were analysed blinded to the clinical diagnosis. IF showed a good diagnostic accuracy (89%) that was lower in the case of skin and CSF-based aSyn-SAA (70% and 69%, respectively) because of a lower sensitivity and specificity. However, IF showed a significant agreement with CSF aSyn-SAA. In conclusion, our data may favor the use of skin biopsy and aSyn-SAA as diagnostic tools for a synucleinopathy in iRBD.

Consistent skin α-synuclein positivity in REM sleep behavior disorder - A two center two-to-four-year follow-up study

OBJECTIVE/METHODS

Phosphorylated alpha-synuclein (p-syn) in dermal nerves of patients with isolated REM sleep behavior disorder (iRBD) is detectable by immunofluorescence-labeling. Skin-biopsy-p-syn-positivity was recently postulated to be a prodromal marker of Parkinson's disease (PD) or related synucleinopathies. Here, we provide two-to four-year clinical and skin biopsy follow-up data of 33 iRBD patients, whose skin biopsy findings at baseline were reported in 2017.

RESULTS

Follow-up biopsies were available from 25 patients (18 positive at baseline) and showed consistent findings over time in 24 patients. One patient converted from skin-biopsy-negativity to -positivity. P-syn-positivity was observed in iRBD patients who still had a normal FP-CIT-SPECT two years later. Clinically, five of the 23 at baseline skin-biopsy-positive patients (21.7%) had converted to PD or dementia with Lewy bodies at follow-up, but none of the skin-biopsy-negative patients.

CONCLUSIONS

Dermal p-syn in iRBD is most probably an early consistent marker of synucleinopathy and may support other indicators of conversion to manifest disease state.

Physical activity and gut microbiota: a cross-sectional study

Background

The composition of gut microbiota, and in particular the intestinal abundance of the two main bacterial phyla of Firmicutes and Bacteroidetes, are associated with human health and diseases and may be conditioned by host and environmental factors such as age, gender and diet. The role of Physical Activity (PA) in determining gut microbiota composition has not been yet completely clarified. A cross-sectional study involving undergraduates from two Italian cities is ongoing to explore this relationship.

Methods

Students were invited to provide a fecal sample and to complete the International Physical Activity Questionnaire (IPAQ) in order to define their habitual PA level (inactive, minimally active, health enhancing physical activity -HEPA- active). Demographic and anthropometric information were also collected. DNA from fecal samples was analyzed through the 16S amplicon sequencing. Microbial composition and variability of the samples were evaluated on the light of participants' PA levels.

Results

A total of 153 students (47.7% males, mean age 22.4±2.9, mean BMI 22.3±2.7) participated to the study so far. Firmicutes and Bacteroidetes were the main represented phyla. An increase in Firmicutes (58.3±16 to 61.4±13.3, p = 0.68) and a reduction in Bacteroidetes (32.6±14.8 to 30.3±11.4, p = 0.51) have been registered with the increase of PA level. A higher variability (expressed as Shannon α-index) has been detected in minimally active (3.39±0.03) and HEPA-active (3.41±0) individuals respect to inactive subjects (3.35±0.07) (p = 0.05).

Conclusions

Even if they are not significant, these preliminary results suggest a relationship between PA levels and gut microbiota composition. An active lifestyle seems to be associated with a greater microbial diversity in the gut. Further researches are needed to explain these findings.

Key messages

Physical activity seems to be associated with gut microbiota composition. A greater variability in gut microbiota was found in active people.

Subgroup comparison according to clinical phenotype and serostatus in autoimmune encephalitis: a multicenter retrospective study

BACKGROUND AND PURPOSE

Autoimmune encephalitides (AE) include a spectrum of neurological disorders whose diagnosis revolves around the detection of neuronal antibodies (Abs). Consensus-based diagnostic criteria (AE-DC) allow clinic-serological subgrouping of AE, with unclear prognostic implications. The impact of AE-DC on patients' management was studied, focusing on the subgroup of Ab-negative-AE.

METHODS

This was a retrospective multicenter study on patients fulfilling AE-DC. All patients underwent Ab testing with commercial cell-based assays (CBAs) and, when available, in-house assays (immunohistochemistry, live/fixed CBAs, neuronal cultures) that contributed to defining final categories. Patients were classified as Ab-positive-AE [N-methyl-d-aspartate-receptor encephalitis (NMDAR-E), Ab-positive limbic encephalitis (LE), definite-AE] or Ab-negative-AE (Ab-negative-LE, probable-AE, possible-AE).

RESULTS

Commercial CBAs detected neuronal Abs in 70/118 (59.3%) patients. Testing 37/48 Ab-negative cases, in-house assays identified Abs in 11 patients (29.7%). A hundred and eighteen patients fulfilled the AE-DC, 81 (68.6%) with Ab-positive-AE (Ab-positive-LE, 40; NMDAR-E, 32; definite-AE, nine) and 37 (31.4%) with Ab-negative-AE (Ab-negative-LE, 17; probable/possible-AE, 20). Clinical phenotypes were similar in Ab-positive-LE versus Ab-negative-LE. Twenty-four/118 (20.3%) patients had tumors, and 19/118 (16.1%) relapsed, regardless of being Ab-positive or Ab-negative. Ab-positive-AE patients were treated earlier than Ab-negative-AE patients (P = 0.045), responded more frequently to treatments (92.3% vs. 65.6%, P < 0.001) and received second-line therapies more often (33.3% vs. 10.8%, P = 0.01). Delays in first-line therapy initiation were associated with poor response (P = 0.022; odds ratio 1.02; confidence interval 1.00-1.04).

CONCLUSIONS

In-house diagnostics improved Ab detection allowing better patient management but was available in a patient subgroup only, implying possible Ab-positive-AE underestimation. Notwithstanding this limitation, our findings suggest that Ab-negative-AE and Ab-positive-AE patients share similar oncological profiles, warranting appropriate tumor screening. Ab-negative-AE patients risk worse responses due to delayed and less aggressive treatments.

Functional MRI study in a case of Charles Bonnet syndrome related to LHON

INTRODUCTION

Charles Bonnet syndrome is characterized by simple or complex visual hallucinations (VH) due to damage along the visual pathways. We report a functional MRI study of brain correlates of VH in the context of a severe optic atrophy in a patient with Leber's Hereditary Optic Neuropathy (LHON).

CASE REPORT

A 62-year-old man was diagnosed with LHON (11778/ND4 mtDNA mutation) after subacute visual loss in left eye (right eye was amblyopic). One month later, he experienced VH of a few seconds consisting in "moving red and blue miniature cartoons". One year later VH content changed in colored mosaic (10-15 s duration), usually stress-related, and blue and white flashes (2-5 s), triggered by unexpected auditory stimuli. Audiometry revealed mild sensorineural hearing loss. Three block design functional MRI paradigms were administrated: 1) random "clap", 2) "checkerboard" and 3) non-random "beep". After random "claps" simple flashes were evoked with bilateral activation of primary and secondary visual cortex, cuneus, precuneus and insula. Neither hallucinations nor cortex activation were registered after "checkerboard" stimulation, due to the severe visual impairment. Primary and secondary auditory cortices were "beep"-activated, without eliciting VH by non-random "beep".

CONCLUSIONS

The peculiarity of our case is that VH were triggered by random auditory stimuli, possibly due to a cross-modal plasticity between visual and auditory networks, likely influenced by the sensorineural deafness. Functional alterations of both networks in resting conditions have been demonstrated in LHON patients, even without an auditory deficit. Finally, the absence of VH triggered by expected stimuli is consistent with the "expectation suppression theory", based on increased neural activations after unexpected but not by predicted events.

Abnormal α-synuclein deposits in skin nerves: intra- and inter-laboratory reproducibility

BACKGROUND AND PURPOSE

Visualization of phosphorylated α-synuclein at serine 129 (p-syn) in skin nerves is a promising test for the in vivo diagnosis of synucleinopathies. Here the aim was to establish the intra- and inter-laboratory reproducibility of measurement of intraneural p-syn immunoreactivity in two laboratories with major expertise (Würzburg and Bologna).

METHODS

In total, 43 patients affected by Parkinson's disease (PD 21 patients), dementia with Lewy bodies (DLB 1), rapid eye movement sleep behaviour disorder (RBD 11), multiple system atrophy (MSA-P 4) and small fibre neuropathy (SFN 6) were enrolled. Skin biopsy was performed at the C7 paravertebral spine region and distal skin sites (thigh or leg). The analysis was standardized in both laboratories and carried out blinded on a single skin section double stained with antibodies to p-syn and the pan-axonal marker protein gene product 9.5. Fifty skin sections were randomly selected for the analysis: 25 from C7 and 25 from distal sites. Differently classified sections were re-evaluated to understand the reasons for the discrepancy.

RESULTS

The intra-laboratory analysis showed an excellent reproducibility both in Würzburg (concordance of classification 100% of sections; K = 1; P < 0.001) and Bologna (96% of sections; K = 0.92; P < 0.001). Inter-laboratory analysis showed reproducibility in 45 sections (90%; K = 0.8; P < 0.001) and a different classification in five sections, which was mainly due to fragmented skin samples or weak fluorescent signals.

CONCLUSIONS

Analysis of p-syn showed excellent inter- and intra-laboratory reproducibility supporting the reliability of this technique. The few ascertained discordances were important to further improve the standardization of this technique.

Procedures in endoscope reprocessing and monitoring: an Italian survey

BACKGROUND

The high diffusion of endoscopes worldwide and the need for effective reprocessing methods requested the development of guidelines and implementation of surveillance procedures at local level.

STUDY DESIGN

In order to collect data on everyday's practice and adherence to available guidelines, endoscopy units from different public institutions were surveyed using a dedicated questionnaire.

METHODS

Between July and November 2015 a survey was carried in 12 main hospitals from 10 different Italian regions, involving 22 endoscopy units. The state of the art of national and international guidelines was investigated to compare the protocols adopted at local level.

RESULTS

In all the surveyed hospitals, the reprocessing activity is based on pre-established protocols in adherence with principal guidelines. Enzymatic detergents, which are recommended by the international guidelines, are used in 55.6% of units and peracetic acid is currently the most widely used chemical disinfectant. Discrepancies were observed in the application of periodic quality controls.

CONCLUSION

Updated guidelines are generally applied in reprocessing practice. Quality controls may represent a critical issue to improve effectiveness and surveillance. The whole of acquired data can promote a positive trend towards the application of best practices.

Bilateral Parry-Romberg Syndrome Associated with Retinal Vasculitis

PURPOSE

To describe an unusual case of bilateral progressive facial hemiatrophy (Parry-Romberg syndrome (PRS)) associated with retinal vasculitis.

METHODS

In a 37-year-old man with bilateral PRS, retinal vasculitis of the right eye was evident on fundus examination and fluorescein angiography. Right temporalis muscle biopsy and needle electromyography of the masseter muscles were performed. The patient underwent immunosuppressive therapy and retinal laser photocoagulation.

RESULTS

Biopsy specimens showed large fibrosis with focal lymphohistiocytic infiltration of the muscle fibers. Electromyographic findings are consistent with a primary muscle disease. Visual acuity improved from 20/25 to 20/20 in the right eye with a follow-up of one year.

CONCLUSIONS

The evidence of retinal vasculitis and the histologic findings of facial changes observed in this PRS case could support the pathogenetic model of a chronic inflammatory process as a plausible explanation for progressive facial hemiatrophy.

The Italian Dystonia Registry: rationale, design and preliminary findings

The Italian Dystonia Registry is a multicenter data collection system that will prospectively assess the phenomenology and natural history of adult-onset dystonia and will serve as a basis for future etiological, pathophysiological and therapeutic studies. In the first 6 months of activity, 20 movement disorders Italian centres have adhered to the registry and 664 patients have been recruited. Baseline historical information from this cohort provides the first general overview of adult-onset dystonia in Italy. The cohort was characterized by a lower education level than the Italian population, and most patients were employed as artisans, builders, farmers, or unskilled workers. The clinical features of our sample confirmed the peculiar characteristics of adult-onset dystonia, i.e. gender preference, peak age at onset in the sixth decade, predominance of cervical dystonia and blepharospasm over the other focal dystonias, and a tendency to spread to adjacent body parts, The sample also confirmed the association between eye symptoms and blepharospasm, whereas no clear association emerged between extracranial injury and dystonia in a body site. Adult-onset dystonia patients and the Italian population shared similar burden of arterial hypertension, type 2 diabetes, coronary heart disease, dyslipidemia, and hypothyroidism, while hyperthyroidism was more frequent in the dystonia population. Geographic stratification of the study population yielded no major difference in the most clinical and phenomenological features of dystonia. Analysis of baseline information from recruited patients indicates that the Italian Dystonia Registry may be a useful tool to capture the real world clinical practice of physicians that visit dystonia patients.

Post-ganglionic autonomic neuropathy associated with anti-glutamic acid decarboxylase antibodies

PURPOSE

Antibodies to glutamic acid decarboxylase (GAD-Abs) have been associated with several conditions, rarely involving the autonomic nervous system. Here, we describe two patients complaining of autonomic symptoms in whom a post-ganglionic autonomic neuropathy has been demonstrated in association with significantly elevated serum and CSF GAD-Abs levels.

METHODS

Patients underwent nerve conduction studies, sympathetic skin response testing, evaluation of autonomic control of the cardiovascular system and skin biopsy. Also, serum screening to exclude predisposing causes of peripheral neuropathy was performed. Anti-GAD65 antibodies were evaluated in serum and CSF.

RESULTS

GAD-Abs titer was increased in both serum and CSF in both patients. Sympathetic skin response was absent and skin biopsy revealed a non-length-dependent small-fiber neuropathy with sympathetic cholinergic and adrenergic post-ganglionic damage in both patients. Nerve conduction studies and evaluation of autonomic control of the cardiovascular system were normal in both patients. Both patients were treated with steroids with good, but partial, (patient 2) recovery of the autonomic dysfunctions.

CONCLUSIONS

Although the pathophysiological mechanisms involved are not fully defined, GAD-abs positivity in serum and CSF should be searched in patients with autonomic neuropathy when no other acquired causes are evident. This positivity may help to clarify autoimmune etiology and, subsequently, to consider immunomodulatory treatment.

LOPED study: looking for an early diagnosis in a late-onset Pompe disease high-risk population

OBJECTIVE

A multicentre observational study was aimed to assess the prevalence of late-onset Pompe disease (LOPD) in a large high-risk population, using the dried blood spot (DBS) as a main screening tool.

DESIGN/METHODS

17 Italian neuromuscular centres were involved in the late-onset Pompe early diagnosis (LOPED) study. Inclusion criteria were: (1) age ≥5 years, (2) persistent hyperCKaemia and (3) muscle weakness at upper and/or lower limbs (limb-girdle muscle weakness, LGMW). Acid α-glucosidase (GAA) activity was measured separately on DBS by fluorometric as well as tandem mass spectrometry methods. A DBS retest was performed in patients resulted positive at first assay. For the final diagnosis, GAA deficiency was confirmed by a biochemical assay in skeletal muscle, whereas genotype was assessed by GAA molecular analysis.

RESULTS

In a 14-month period, we studied 1051 cases: 30 positive samples (2.9%) were detected by first DBS screening, whereas, after retesting, 21 samples were still positive. Biochemical and molecular genetic studies finally confirmed LOPD diagnosis in 17 cases (1.6%). The median time from the onset of symptoms/signs to diagnosis was 5 years. Among those patients, 35% showed presymptomatic hyperCKaemia and 59% showed hyperCKaemia+LGMW, whereas 6% manifested with LGMW.

CONCLUSIONS

LOPED study suggests that GAA activity should be accurately screened by DBS in all patients referring for isolated hyperCKaemia and/or LGMW. A timely diagnosis was performed in five patients with presymptomatic hyperCKaemia, but two had already manifested with relevant changes on muscle morphology and MRI. Consequently, enzyme replacement therapy was started in 14/17 patients, including the 2 patients still clinically presymptomatic but with a laboratory evidence of disease progression.

Overcoming recurrent spontaneous abortions in women suffering from IgG subclass deficiency: high efficiency of low dose intravenous immunoglobulins treatment

PROBLEM

It's well known that iv. immunoglobulins may be useful to overcome habitual abortions, but the mechanisms at the base of a successful outcome and the likelihoods are still unknown.

METHOD OF STUDY

In one hundred and sixty women with habitual abortions and one hundred and sixty healthy mothers, we evaluated blood IgG subclasses; among the patients, sixteen merely showed IgG subclass deficiency, after leaving out any autoimmunity and/or coagulation disorders. All the patients (100%) showed IgG3, twelve (75%) IgG1, eight (50%) IgG4 and six (37,5%) IgG2 deficiency; healthy control people's IgG subclasses fell in normal range in 156 women, but just four women showed IgG2 and IgG4 deficiency with neither immune deficiency's clinical marks nor increased vulnerability to infections. All the patients were treated with whole immunoglobulins iv. infusion (200 mg/kg/monthly) all over the pregnancy.

RESULTS

The successful pregnancy rate is very high (>90%): 100% out of women showing IgG1 (12/12), 87,5% of IgG3 (14/16), 75% of IgG4 (6/8) and 66% of IgG2 deficiency (4/6) had successful pregnancies. The Odd's Ratio between IgG subclass deficiency and recurrent abortions is 4,33 with confidence interval of 95%; chi square value is 7.68 (p<0.025).

CONCLUSIONS

Low dose immunoglobulin infusion is the only effective way to reach successful pregnancy, despite previous habitual abortions in patients suffering from IgG subclass deficiency without autoimmunity and/or coagulation disorders, likely restoring idiotype-antiidiotype network; showing evidence of IgG subclasses deficiency (mostly IgG1 and IgG3) may help identify patients who can benefit from iv. immunoglobulin treatment.

Neuropathic pain following spinal cord injury: what we know about mechanisms, assessment and management

BACKGROUND

In biology, it is easy to understand how a damaged functional system may generate wrong signals, but why this should happen when the system is disconnected is less clear. For this reason, among other pain syndromes, neuropathic pain (NP) following spinal cord injury (SCI) leaves most questions unanswered.

AIMS AND METHODS

Our purpose is to review current knowledge on NP after SCI, focusing on the mechanisms, assessment and management of the syndrome.

RESULTS

The mechanisms responsible for NP following SCI are poorly understood: NP is classically considered a "central pain syndrome" but recent evidence from experimental models reveals a possible "peripheral sensitization". Assessment of NP following SCI is well-established: in addition to clinical evaluation and self-reported scales, many neurophysiological, radiological and microscopic investigations may be performed. The management of NP following SCI is very difficult: evidence of effective drugs is lacking and alternative new treatment approaches yield different outcomes.

CONCLUSIONS

Recently clinical and instrumental tools have increased our knowledge on NP, suggesting that the discovery of new treatment agents will depend on an explanation of what changes after SCI: future research must point in this direction.