Late-onset Pompe disease: a genetic-radiological correlation on cerebral vascular anomalies

Pompe disease is an autosomal recessive disorder in which deficiency of the lysosomal enzyme acid alpha-glucosidase results in the accumulation of glycogen mostly in muscle tissues. Several reports suggest a higher incidence of intracranial vascular abnormalities (IVAs) in this condition, as well as brain microbleeds and cerebral vasculopathy. The aim of our study was to evaluate through neuroimaging studies the incidence of these anomalies in our cohort of late-onset Pompe disease (LOPD) patients asymptomatic for cerebrovascular disease, looking for correlations with clinical and genetic data. We studied 18 LOPD patients with brain magnetic resonance angiography (MRA), or contrast-enhanced computed tomography (CECT). Diameters of individual arteries were measured and compared with average values as proposed in the literature. We found IVAs in 13 of the 18 patients, mostly dilatative arteriopathy affecting the vertebrobasilar system. The anterior circle was involved in seven of the 18 patients. The diameter of the basilar artery at 1 cm was found to correlate both with age (spearman rho, p = 0.037) and disease duration (p = 0.004), but no other statistically significant correlation was documented. The incidence of intracranial dilatative arteriopathy in LOPD was higher than in the general population, confirming the literature data. However, we did not find intracranial aneurysms microbleeds or significant cerebrovascular disease. Abnormalities in the anterior and the posterior circle of Willis correlated with age and disease duration, but not with the severity of muscle/respiratory involvement or with genetic data. Further studies in larger cohorts of patients are needed to confirm these findings.

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.

Electrophysiological patterns of oropharyngeal swallowing in multiple sclerosis

OBJECTIVE

We performed an electrophysiological study of swallowing (EPSS) in multiple sclerosis (MS) to describe oropharyngeal swallowing abnormalities and to analyze their correlations with dysphagia and with overall neurological impairment.

METHODS

Neurological examinations were quantified using the Kurtzke Functional Systems and the Expanded Disability Status Scale (EDSS). Dysphagia was evaluated using the Dysphagia in Multiple Sclerosis (DYMUS) questionnaire, while fiberoptic endoscopic evaluation of swallowing (FEES) was used to establish the degree of aspiration and penetration, graded using the penetration-aspiration scale (PAS). The EPSS measured the duration of suprahyoid/submental muscle EMG activity (SHEMG-D), the duration of the laryngeal-pharyngeal mechanogram (LPM-D), and the duration of the pause in cricopharyngeal muscle EMG activity (CPEMG-PD); it also measured the interval between onset of the suprahyoid/submental muscle EMG activity (SHEMG) and onset of the laryngeal-pharyngeal mechanogram (I-SHEMG-LPM).

RESULTS

92% of patients showed at least one electrophysiological abnormality. I-SHEMG-LPM correlated positively with the DYMUS questionnaire. I-SHEMG-LPM, SHEMG-D, and DYMUS correlated positively with the PAS. Moderate to severe bladder sphincter dysfunction was associated with a significant reduction, or absence, of CPEMG-PD.

CONCLUSION

EPSS improves our understanding of the pathophysiology of dysphagia in MS.

SIGNIFICANCE

This investigation could be useful in MS patients with swallowing abnormalities.

Microscale oxygraphy reveals OXPHOS impairment in MRC mutant cells

Given the complexity of the respiratory chain structure, assembly and regulation, the diagnostic workout for the identification of defects of oxidative phosphorylation (OXPHOS) is a major challenge. Spectrophotometric assays, that measure the activity of individual respiratory complexes in tissue and cell homogenates or isolated mitochondria, are highly specific, but their utilization is limited by the availability of sufficient biological material and intrinsic sensitivity. A further limitation is tissue specificity, which usually determines attenuation, or disappearance, in cultured fibroblasts, of defects detected in muscle or liver. We used numerous fibroblast cell lines derived from patients with OXPHOS deficiencies to set up experimental protocols required for the direct readout of cellular respiration using the Seahorse XF96 apparatus, which measures oxygen consumption rate (OCR) and extra-cellular acidification rate (ECAR) in 96 well plates. Results demonstrate that first level screening based on microscale oxygraphy is more sensitive, cheaper and rapid than spectrophotometry for the biochemical evaluation of cells from patients with suspected mitochondrial disorders.

Observational clinical study in juvenile-adult glycogenosis type 2 patients undergoing enzyme replacement therapy for up to 4 years

The objective of this study was to describe a large Italian cohort of patients with late-onset glycogen storage disease type 2 (GSDII) at various stages of disease progression and to evaluate the clinical effectiveness of alglucosidase alpha enzyme replacement therapy (ERT). Previous studies showed in late-onset patients ERT efficacy against placebo and variable response in uncontrolled studies. Seventy-four juvenile or adult GSDII patients were treated with ERT in a multicenter open label, non-randomized study, from 12 months up to 54 months. Recombinant human alpha glucosidase (rh-GAA) was injected by intravenous route at 20 mg/kg every second week. Patients were divided into three groups according to ERT duration: Group A received treatment for 12-23 months (n = 16), Group B for 24-35 months (n = 14), and Group C for more than 36 months (n = 44). Clinical assessment included a 6-min walk test (6MWT), forced vital capacity (FVC), the Walton and Gardner-Medwin score, the number of hours of ventilation, body mass index, echocardiography and blood creatine kinase (CK). Included in our cohort were 33 males and 41 females (M:F = 0.8:1), with a mean age at first symptoms of 28.3 years (range 2-55 years) and a mean age of 43 years at study entry (range 7-72 years). Seven wheelchair bound patients, as well as 27 patients requiring ventilation support, were included. After treatment we could observe an increase in distance walked on the 6MWT in the large majority of patients (48/58; 83%), with an overall mean increase of 63 m (from 320 ± 161 to 383 ± 178 m). After treatment in the majority of patients FVC was improved or unchanged (45/69; 65%). In ventilated patients we observed an improvement in average number of hours off the ventilator (from 15.6 to 12.1 h). Six patients stopped mechanical ventilation and two others started it. The effect of therapy was not related to ERT duration. Nine of 64 patients (13%) that underwent to echocardiography showed a variable degree of cardiac hypertrophy (left ventriculum or septum), and a positive effect was observed after 36 months of ERT in one adult case. Discontinuation of treatment occurred in four patients: one drop-off case, one patient died for a sepsis after 34 months of treatment and two patients stopped ERT for worsening of general clinical condition. Mild adverse effects were observed in four cases (5%). This study represents the largest cohort of late-onset GSDII patients treated with ERT, and confirm a positive effect of treatment. These results, obtained in a large case series on therapy, indicate a favourable effect of ERT therapy, even in more advanced stage of the disease.

Changes in nutritional status and body composition during enzyme replacement therapy in adult-onset type II glycogenosis

BACKGROUND

In adult glycogen storage disease type II (GSDII), a single-gene mutation causes reduction of the lysosomal enzyme acid alpha-glucosidse. This produces a chronic proximal myopathy with respiratory involvement. Enzyme replacement treatment (ERT) has recently become available and is expected to improve muscle strength. This should result in increased lean body mass. In this study we evaluate body composition and nutritional status in GSDII, and assess whether these parameters changed during treatment.

METHODS

Seventeen patients with late-onset GSDII, aged 52.6 +/- 16.8 years, received ERT for >18 months. Dietary habits and metabolic profiles of glucids, lipids, and proteins were assessed. Body composition was calculated using anthropometry and bioelectrical impedence analysis.

RESULTS

On inclusion, we found increased fat mass (FM) in five patients in severe disease stage; all had normal body mass index (BMI). FM correlated inversely, and lean mass (LM) directly, with creatine kinase, prealbumin and albumin levels. After treatment, BMI and FM significantly increased, while LM only showed a trend toward increase. Prealbumin and albumin levels increased as early as after the first months of ERT.

DISCUSSION

Body mass index value may underestimate FM in patients in severe stage of disease, due to altered body composition. In severely affected patients, laboratory parameters revealed a relative protein malnutrition, that was reversed by ERT, this reflecting restoration of normal muscle metabolic pathways. Increased BMI may indicate a reduction in energy consumption during exercise or respiration, along with clinical improvement.

Enzyme replacement therapy in adult-onset glycogenosis II: is quantitative muscle MRI helpful?

Although it has been shown that muscle magnetic resonance imaging (MRI) improves the phenotypic characterization of patients with neuromuscular disorders and allows accurate quantification of muscle and adipose tissue distribution, to date quantitative MRI has not been used to assess the therapeutic response in clinical trials of neuromuscular diseases. We discuss quantitative MRI findings after a 6-month course of enzyme replacement therapy administered to nine patients with adult-onset glycogenosis II.

Diagnosis of glycogenosis type II

The diagnosis of glycogenosis type II is often complicated by the rarity of the condition and the heterogeneity of the clinical manifestations of the disease. It is a progressive, debilitating, and often fatal neuromuscular disorder that manifests as a continuum of clinical phenotypes, which vary with respect to organ involvement, age at onset, and severity. Early diagnosis requires both increased awareness among physicians regarding the clinical characteristics of the disease and fast and reliable acid alpha-glucosidase (GAA) enzyme activity assays to confirm the GAA deficiency. The clinical diagnosis of glycogenosis type II is confirmed by virtual absence (found in infants) and marked reduced activity (found in juveniles and adults) of GAA enzyme in blood samples, cultured fibroblasts, and muscle biopsies. This article specifically highlights the need for early recognition of the clinical manifestation of the disease in infants, juveniles, and adults. Descriptions of the main clinical features of the condition, as well as differential diagnosis are included. In addition, the tests required for a confirmed diagnosis are described, and use of muscle imaging to evaluate muscle pathology is reviewed.

Postinfectious inflammatory disorders: Subgroups based on prospective follow-up

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) refers to a monophasic acute multifocal inflammatory CNS disease. However, both relapsing and site-restricted variants, possibly associated with peripheral nervous system (PNS) involvement, are also observed, and a systematic classification is lacking.

OBJECTIVE

To describe a cohort of postinfectious ADEM patients, to propose a classification based on clinical and instrumental features, and to identify subgroups of patients with different prognostic factors.

METHODS

Inpatients of a Neurologic and Infectious Disease Clinic affected by postinfectious CNS syndrome consecutively admitted over 5 years were studied.

RESULTS

Of 75 patients enrolled, 60 fulfilled criteria for ADEM after follow-up lasting from 24 months to 7 years. Based on lesion distribution, patients were classified as encephalitis (20%), myelitis (23.3%), encephalomyelitis (13.3%), encephalomyeloradiculoneuritis (26.7%), and myeloradiculoneuritis (16.7%). Thirty patients (50%) had a favorable outcome. Fifteen patients (25%) showed a relapsing course. Poor outcome was related with older age at onset, female gender, elevated CSF proteins, and spinal cord and PNS involvement. All but two patients received high-dose steroids as first-line treatment, with a positive response in 39 (67%). Ten of 19 nonresponders (53%) benefited from high-dose IV immunoglobulin; 9 of 10 had PNS involvement. The data were not controlled.

CONCLUSIONS

A high prevalence of "atypical variants" was found in this series, with site-restricted damage or additional peripheral nervous system (PNS) involvement. Prognosis and response to steroids were generally good, except for some patient subgroups. In patients with PNS involvement and steroid failure, a favorable effect of IV immunoglobulin was observed.

Nitric oxide pathway and response to nitroglycerin in cluster headache patients: plasma nitrite and citrulline levels

Nitric oxide (NO) may participate in the mechanisms underlying vascular headaches, such as migraine and cluster headache (CH), by triggering neurogenic inflammation and activation of fibres conveying nociceptive inputs to the trigeminal ganglion. Similarly to migraine, the administration of the NO donor glyceryltrinitrate (GTN) to CH patients is a known model of inducing spontaneous-like attacks. We carried out a GTN test (0.9 mg, sublingually) in 18 patients with episodic CH in active phase and 12 controls. The plasma levels of NO metabolite nitrites (NO2-), after conversion of nitrates to NO2-, were measured spectrophotometrically at baseline, at the maximum intensity of the induced response (or 45 min after GTN in controls), and 120 min after GTN administration. The basal plasma levels of L-citrulline were also assayed in patients and controls using high-performance liquid chromatography. Basal NO2- levels, similar in GTN-responsive patients and controls (48.3 +/- 10.6 and 44.6 +/- 9.5 micromol/l, respectively) were found to be increased significantly at pain peak in patients (76.1 +/- 10.2 micromol/l) and after 45 min in controls (78.2 +/- 9.6 micromol/l) (P < 0.01 vs. respective baseline values), but not after 120 min, without differences between groups. L-citrulline levels in basal conditions showed no differences between groups (patients 64.8 +/- 11.7, controls 67.3 +/- 10.8 micromol/l). These data do not support the presence of a basal hyperactivity of the L-arginine-NO pathway in CH patients. Increased NO production may be of importance in the mechanisms leading to CH attacks, but other factors are likely to render CH patients hyperresponsive to NO, and ultimately to cause the occurrence of pain and associated features.

Molecular cloning and expression of an interferon-inducible protein encoded by gene 203 from the gene 200 cluster

We report here the complete coding sequence of a 203 cDNA, a member of the interferon-inducible Ifi 200 gene family. By combining reverse-transcriptase PCR and rapid amplification of cDNA ends (RACE) techniques we have obtained a 3.8-kb cDNA corresponding to a 203 mRNA. When used as a probe in northern analysis, its 3' segment hybridized to a 3.8-kb interferon-inducible mRNA, whereas the 5'-end additionally hybridized to a less abundant interferon-inducible 1.8-kb mRNA. Nucleotide sequence analysis revealed that the two mRNAs share the 5'-untranslated region and the same open reading frame, which encodes a hydrophilic protein composed of 408 amino acids. The difference between them is due to a 3'-untranslated region extended by alternative polyadenylation site selection. Furthermore, 203 mRNA was found to be inducible by interferon-alpha in various murine cell lines. Using polyclonal antibodies raised against a segment specific for the 203 protein, we established that p203 protein levels increase on treatment with interferon-alpha in murine fibroblasts and that p203 is located in the nucleus.

The murine cytomegalovirus immediate-early 1 protein stimulates NF-kappa B activity by transactivating the NF-kappa B p105/p50 promoter

The transcription of murine cytomegalovirus (MCMV) immediate-early (IE) genes is regulated by a large and complex enhancer containing several consensus binding sites for the ubiquitous transcription factor NF-kappa B. To verify whether MCMV, like the human CMV, can activate NF-kappa B-dependent transcription, we transfected murine embryo fibroblasts cells with a construct containing three copies of the NF-kappa B element in front of the homologous minimal MCMV IE1-3 promoter. Upon MCMV infection the reporter gene activity was transactivated to about three-fold above the basal level. The specificity of this transactivation was demonstrated by the lack of any significant effect on the activity of DNA constructs containing either a mutated NF-kappa B trimer or an ATF/CRE trimer. Gel shift assays with a NF-kappa B probe revealed that MCMV infection activated DNA binding proteins showing NF-kappa B characteristics. The DNA-binding activity remained elevated during the course of infection and was associated to an increase in the steady-state mRNA levels for the NF-kappa B subunit p105/p50. Since the promoter of the p105/p50 gene was transactivated by MCMV infection during the period in which the IE proteins are expressed, the role of the two major IE transcriptional regulatory proteins was examined. In cotransfection experiments, the IE1 protein transactivated the p105/p50 promoter, whereas the IE3 was ineffective in increasing the transcription of the reporter gene. Taken as a whole, these results demonstrate that MCMV, like its human counterpart, regulates the cellular NF-kappa B activity needed for the initial induction of the IE genes and the progression of the viral replicative cycle.

Interferon-alpha inhibits the murine cytomegalovirus immediate-early gene expression by down-regulating NF-kappa B activity

Transcription of murine cytomegalovirus (MCMV) immediate-early (IE) genes is regulated by the interaction of cellular transcription factors with a strong viral enhancer controlling promoters flanking both sides of the regulatory sequence. We have previously demonstrated that interferon-alpha (IFN-alpha) inhibits MCMV replication by impairing the transcription of IE genes. To define the cis-acting elements and trans-acting factors involved in this inhibition, permissive murine fibroblasts were transferred with DNA constructs containing the chloramphenicol acetyl transferase reporter gene and portions of the IE enhanced. The region spanning -1185 to -259 relative to the IE1-3 promoter was sufficient to allow IFN-alpha-induced inhibition. Since this segment contains several NF-kappa B sites, cells were transfected with a construct containing three copies of NF-kappa B element in front of the homologous minimal IE1-3 promoter. Upon IFN-alpha treatment the reporter gene activity was strongly reduced, indicating that NF-kappa B binding site is sufficient to confer inhibition. The specificity of this inhibition was demonstrated by the lack of a significant effect on the activity of DNA constructs containing either a mutated NF-kappa B trimer or an ATF/CRE trimer. Gel shift assays with NF-kappa B probes revealed that MCMV infection activated NF-kappa B proteins, whereas IFN-alpha treatment significantly reduced their ability to bind NF-kappa B sites. In cotransfection experiments using various NF-kappa B subunit expression vectors and a reporter driven by three copies of an NF-kappa B element, activation of NF-kappa B-dependent transcription was observed with expression of p65 or combinations of p50-p65. Taken as a whole, these results suggest that IFN-alpha inhibits MCMV IE gene enhancer activity by mechanisms that decrease the availability of virus-induced NF-kappa B transcriptionally active in the nuclei of infected cells.

Interferons inhibit onset of murine cytomegalovirus immediate-early gene transcription

Treatment of NIH 3T3 fibroblasts with interferon-alpha or interferon-gamma (IFN-alpha or IFN-gamma) significantly reduced murine cytomegalovirus (MCMV) replication. Determination of viral DNA in the nuclei of the infected cells before onset of DNA replication demonstrated that virus uptake, transport to the nucleus, and DNA stability were not decreased. Analysis of the virus specified mRNAs soon after infection revealed that in the cells exposed to IFNs expression of the immediate early (IE) genes was strongly reduced. Nuclear run-off transcription analysis showed that this inhibition is due to significant reduction of IE gene transcription rates following IFN treatment. Since transcription of the MCMV IE region is regulated by a strong enhancer element, a construct containing the chloramphenicol acetyltransferase (CAT) reporter gene, driven by an 1.2 kb segment spanning the enhancer and IE1/3 promoter region of the IE transcription unit, was transfected into NIH 3T3 cells. Treatment with IFN-alpha or IFN-gamma after transfection strongly reduced CAT activity compared to untreated controls. In an attempt to define a negative IFN-responsive element in the IE enhancer, a series of deletion mutants driving the CAT reporter gene were transfected into NIH 3T3 cells that were then treated with IFN-alpha. With the sole exception of the construct containing the minimal MCMV IE1/3 promoter (-102 to the cap site), all other deletion mutants were strongly down-regulated by IFN-alpha-treatment. Taken as a whole, these results suggest that IFNs inhibit MCMV replication by impairing the transcription of the IE transcription units, and that this negative regulation is carried out by sequences scattered throughout the IE enhancer region.