Mauro Ceroni

Expression polymorphism of the blood-brain barrier component P-glycoprotein (MDR1) in relation to Parkinson's disease

Because drug transporters such as P-glycoprotein, the product of the multidrug resistance (MDR1 ) gene, contribute to the function of the blood-brain barrier, we hypothesized that differences in their expression could affect the uptake of neurotoxic xenobiotics, thereby modulating interindividual susceptibility for neurological disorders such as Parkinsons disease. In a pilot case-control study comprising 95 Parkinsons disease patients (25 early-onset patients with onset age < or = 45 years) and 106 controls we analysed the three common polymorphisms, 3435C >T in exon 26, 2677G > T,A in exon 21, and -129T > C in exon 1b. There were no statistically significant associations between any of these polymorphisms and Parkinsons disease. However, a distribution pattern consistent with our hypothesis was observed in that the frequency of the 3435T/T genotype, which had previously been associated with decreased P-glycoprotein expression and function, was highest in the early-onset Parkinsons disease group (36.0%), second-highest in the late-onset Parkinsons disease group (22.9%), and lowest in the control group (18.9%). Furthermore, we confirmed that the MDR1 exon 21 and exon 26 polymorphisms are in significant linkage disequilibrium since the [2677G, 3435C] and [2677T, 3435T] haplotypes were far more frequently observed than expected. In conclusion, MDR1 and other drug transporters represent plausible candidates as Parkinsons disease risk genes. Larger studies are required to confirm this role in the etiology of Parkinsons disease.

Mutations of FUS Gene in Sporadic Amyotrophic Lateral Sclerosis

Background Mutations in the FUS gene have recently been discovered to be a major cause of familial amyotrophic lateral sclerosis (FALS). Objective To determine the identity and frequency of FUS gene mutations in a large cohort of Italian patients enriched in sporadic cases (SALS). Methods Exons 5, 6, 14 and 15 of the FUS gene were screened for mutations in 1009 patients (45 FALS and 964 SALS). The genetic analysis was extended to the entire coding sequence of FUS in all the FALS and 293 of the SALS patients. Results Seven missense mutations (p.G191S, p.R216C, p.G225V, p.G230C, p.R234C, p.G507D and p.R521C) were identified in nine patients (seven SALS and two FALS), and none in 500 healthy Italian controls. All mutations are novel except for the p.R521C mutation identified in one SALS and one FALS case. Both patients showed a similar unusual presentation, with proximal, mostly symmetrical, upper limb weakness, with neck and axial involvement. With the exception of p.G507D and p.R521C, the mutations identified in SALS patients are all localised in the glycine-rich region encoded by exon 6. In addition, eight different in-frame deletions in two polyglycine motifs were detected, the frequency of which was not significantly different in patients and controls. Conclusions The results show that FUS missense mutations are present in 0.7% of Italian SALS cases, and confirm the previous mutational frequency reported in FALS (4.4%). An unusual proximal and axial clinical presentation seems to be associated with the presence of the p.R521C mutation.

Human Leukocyte Antigen and Antigen Processing Machinery Component Defects in Astrocytic Tumors

Purpose: To determine the frequency of abnormalities in human leukocyte antigen (HLA) and antigen processing machinery (APM) component expression in malignant brain tumors. This information may contribute to our understanding of the immune escape mechanisms used by malignant brain tumors because HLA antigens mediate interactions of tumor cells with the hosts immune system. Experimental Design: Eighty-eight surgically removed malignant astrocytic tumors, classified according to the WHO criteria, were stained in immunoperoxidase reactions with monoclonal antibody recognizing monomorphic, locus-specific, and allospecific determinants of HLA class I antigens, β2-microglobulin, APM components (LMP2, LMP7, TAP1, TAP2, calnexin, calreticulin, and tapasin), and HLA class II antigens. Results: HLA class I antigens were lost in ∼50% of the 47 glioblastoma multiforme (GBM) lesions and in ∼20% of the 18 grade 2 astrocytoma lesions stained. Selective HLA-A2 antigen loss was observed in ∼80% of the 24 GBM lesions and in ∼50% of the 12 grade 2 astrocytoma lesions stained. HLA class I antigen loss was significantly (P < 0.025) correlated with tumor grade. Among the APM components investigated, tapasin expression was down-regulated in ∼20% of the GBM lesions analyzed; it was associated, although not significantly, with HLA class I antigen down-regulation and tumor grade. HLA class II antigen expression was detected in ∼30% of the 44 lesions analyzed. Conclusion: The presence of HLA antigen defects in malignant brain tumors may provide an explanation for the relatively poor clinical response rates observed in the majority of the T cell–based immunotherapy clinical trials conducted to date in patients with malignant brain tumors.

Amyotrophic lateral sclerosis Oxidative energy metabolism and calcium homeostasis in peripheral blood lymphocytes

There is evidence of oxidative injury in postmortem brain, spinal cord, and CSF of patients with sporadic amyotrophic lateral sclerosis (SALS patients).We investigated the oxidative metabolism and calcium homeostasis in peripheral blood lymphocytes from such patients and did not find statistical differences in the basal oxygen consumption rate (QO2), cytochrome c oxidase activity, catalase activity, and lactate production. However the increase in QO2, induced by an uncoupler of oxidative phosphorylation, was depressed and the basal (resting) level of free cytosolic calcium ([Ca2+] sub in) was higher in lymphocytes from SALS patients (p < 0.01). Further increase in free [Ca2+]in challenged by a K sup + channel blocker or by an uncoupler of oxidative phosphorylation was similar in SALS and control lymphocytes. The results show that systemic changes consistent with the presence of mitochondrial and of calcium metabolism dysfunction are present in SALS. NEUROLOGY 1996;47: 1060-1064

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.

An over-oxidized form of superoxide dismutase found in sporadic amyotrophic lateral sclerosis with bulbar onset shares a toxic mechanism with mutant SOD1

Recent studies suggest that Cu/Zn superoxide dismutase (SOD1) could be pathogenic in both familial and sporadic amyotrophic lateral sclerosis (ALS) through either inheritable or nonheritable modifications. The presence of a misfolded WT SOD1 in patients with sporadic ALS, along with the recently reported evidence that reducing SOD1 levels in astrocytes derived from sporadic patients inhibits astrocyte-mediated toxicity on motor neurons, suggest that WT SOD1 may acquire toxic properties similar to familial ALS-linked mutant SOD1, perhaps through posttranslational modifications. Using patients’ lymphoblasts, we show here that indeed WT SOD1 is modified posttranslationally in sporadic ALS and is iper-oxidized (i.e., above baseline oxidation levels) in a subset of patients with bulbar onset. Derivatization analysis of oxidized carbonyl compounds performed on immunoprecipitated SOD1 identified an iper-oxidized SOD1 that recapitulates mutant SOD1-like properties and damages mitochondria by forming a toxic complex with mitochondrial Bcl-2. This study conclusively demonstrates the existence of an iper-oxidized SOD1 with toxic properties in patient-derived cells and identifies a common SOD1-dependent toxicity between mutant SOD1-linked familial ALS and a subset of sporadic ALS, providing an opportunity to develop biomarkers to subclassify ALS and devise SOD1-based therapies that go beyond the small group of patients with mutant SOD1.

Effectiveness of intravenous immunoglobulin treatment in adult patients with steroid-resistant monophasic or recurrent acute disseminated encephalomyelitis

Abstract Randomized Controlled Trials have not jet established the best pharmacological management of Acute Disseminated Encephalomyelitis (ADEM). High dose steroids are usually employed with good results, but in a few cases the clinical outcome is poor. In other patients, particularly those affected by the site restricted ADEM variants (myelitis), the disease shows a recurrent course resembling that of Multiple Sclerosis. We present here five patients, 3 of them affected by classic disseminated encephalomyelitis and 2 by a post infectious myelitis, which showed a good response to intravenous immunoglobulin (IVIg) after steroid treatment failure. In our report high dose steroids administration was substantially uneffective in all but one case, who showed a good response only during the first episode. On the contrary IVIg injection (0,4 gr/kg/day) produced a marked functional improvement in all patients starting within the first five days of drug administration and reaching a maximum within three weeks. One patient experienced a good effect nothwithstanding a steady dysability. In all cases, clinical evidence was supported by MRI controls showing improving posttreatment changes.

Immunohistochemical localization of prion protein in spongiform encephalopathies and normal brain tissue

We used polyclonal antibodies raised against hamster and mouse PrP27–30 as immunologic probes to study the localization of intracellular and extracellular deposits of prion protein in normal and scrapie-infected mouse and hamster brains and in Creutzfeldt-Jakob disease (CJD)-infected mouse brains. In addition, we examined normal human brain and brain tissues from patients with CJD, kuru, Alzheimers disease, and idiopathic chronic encephalitis. There was positive staining in the cytoplasm of neurons of normal and scrapie- and CJD-infected mice, and in the neurons of normal and scrapie-infected hamsters. The staining pattern suggests the localization of PrP in an intracellular membrane compartment, most likely the rough endoplasmic reticulum or Golgi apparatus. Antibodies raised against a 15-amino-acid synthetic peptide of the N-terminal of hamster PrP27–30 displayed a similar pattern of staining in mouse brain sections. We observed no intracellular staining in human brain sections obtained at autopsy. Antibodies prepared against mouse and hamster PrP27–30 reacted with amyloid plaques in scrapie-infected mouse and kuru- and CJD-infected human brain sections but not with amyloid plaques in the brain of a patient with Alzheimers disease.

Diagnostic Potential of Autofluorescence for an Assisted Intraoperative Delineation of Glioblastoma Resection Margins

Abstract The intrinsic autofluorescence properties of biological tissues can be affected by the occurrence of histological and biochemical alterations induced by pathological processes. In this study the potential of autofluorescence to distinguish tumor from normal tissues was investigated with the view of a real-time diagnostic application in neurosurgery to delineate glioblastoma resection margins. The autofluorescence properties of nonneoplastic and neoplastic tissues were analyzed on tissue sections and homogenates by means of a microspectrofluorometer, and directly on patients affected by glioblastoma multiforme, during surgery, with a fiber-optic probe. Scan-microspectrofluorometric analysis on tissue sections evidenced a reduction of emission intensity and a broadening of the main emission band, along with a redshift of the peak position, from peritumoral nonneoplastic to neoplastic tissues. Differences in both spectral shape and signal amplitude were found in patients when the glioblastoma lesion autofluorescence was compared with those of cortex and white matter taken as healthy tissues. Both biochemical composition and histological organization contribute to modify the autofluorescence emission of neoplastic, with respect to nonneoplastic, brain tissues. The differences found in the in vivo analysis confirm the prospects for improving the efficacy of tumor resection margin delineation in neurosurgery.

C9ORF72 repeat expansion in a large Italian ALS cohort: evidence of a founder effect

A hexanucleotide repeat expansion (RE) in C9ORF72 gene was recently reported as the main cause of amyotrophic lateral sclerosis (ALS) and cases with frontotemporal dementia. We screened C9ORF72 in a large cohort of 259 familial ALS, 1275 sporadic ALS, and 862 control individuals of Italian descent. We found RE in 23.9% familial ALS, 5.1% sporadic ALS, and 0.2% controls. Two cases carried the RE together with mutations in other ALS-associated genes. The phenotype of RE carriers was characterized by bulbar-onset, shorter survival, and association with cognitive and behavioral impairment. Extrapyramidal and cerebellar signs were also observed in few patients. Genotype data revealed that 95% of RE carriers shared a restricted 10-single nucleotide polymorphism haplotype within the previously reported 20-single nucleotide polymorphism risk haplotype, detectable in only 27% of nonexpanded ALS cases and in 28% of controls, suggesting a common founder with cohorts of North European ancestry. Although C9ORF72 RE segregates with disease, the identification of RE both in controls and in patients carrying additional pathogenic mutations suggests that penetrance and phenotypic expression of C9ORF72 RE may depend on additional genetic risk factors.