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Contains fulltext : 248871.pdf (Publisher’s version ) (Open Access) BACKGROUND: Previous studies showed that lifestyle behaviors (cigarette smoking, alcohol, coffee) are inversely associated with Parkinson's disease (PD). The prodromal phase of PD raises the possibility that these associations may be explained by reverse causation. OBJECTIVE: To examine associations of lifestyle behaviors with PD using two-sample Mendelian randomisation (MR) and the potential for survival and incidence-prevalence biases. METHODS: We used summary statistics from publicly available studies to estimate the association of genetic polymorphisms with lifestyle behaviors, and from Courage-PD (7,369 cases, 7,018 controls; European ancestry) to estimate the association of these variants with PD. We used the inverse-variance weighted method to compute odds ratios (ORIVW) of PD and 95%confidence intervals (CI). Significance was determined using a Bonferroni-corrected significance threshold (p = 0.017). RESULTS: We found a significant inverse association between smoking initiation and PD (ORIVW per 1-SD increase in the prevalence of ever smoking = 0.74, 95%CI = 0.60-0.93, p = 0.009) without significant directional pleiotropy. Associations in participants ≤67 years old and cases with disease duration ≤7 years were of a similar size. No significant associations were observed for alcohol and coffee drinking. In reverse MR, genetic liability toward PD was not associated with smoking or coffee drinking but was positively associated with alcohol drinking. CONCLUSION: Our findings are in favor of an inverse association between smoking and PD that is not explained by reverse causation, confounding, and survival or incidence-prevalence biases. Genetic liability toward PD was positively associated with alcohol drinking. Conclusions on the association of alcohol and coffee drinking with PD are hampered by insufficient statistical power.

COQ2 encodes para-hydroxybenzoate-polyprenyl transferase and, recently, mutations in this gene have been associated with the increase of the risk of multiple system atrophy (MSA) in Japanese cases. Subsequently, studies in Asian patients confirmed the role of COQ2 in the development of MSA, while other analysis failed to replicate these results in Caucasian population. We performed genetics screening of COQ2 in 100 MSA Italian patients. We did not find any pathogenic mutations; our results suggest that COQ2 is not a genetic risk factor for MSA in Italian population.

DCTN1 encodes the largest subunit of dynactin complex essential in the retrograde axonal transport and cytoplasmic transport of vesicles; mutations in DCTN1 have been reported predominantly in individuals with Perry syndrome and, recently, in patients with progressive supranuclear palsy. Our genetic screening of DCTN1 in 79 patients with progressive supranuclear palsy, 100 patients with multiple system atrophy, and 28 patients with dementia with Lewy bodies from Italy revealed only synonymous and intronic variants, suggesting that DCTN1 mutations do not have a key role in the development of atypical parkinsonism in the Italian population.

HSPA8/hsc70 (70-kDa heat shock cognate) chaperone protein exerts multiple protective roles. Beside its ability to confer to the cells a generic resistance against several metabolic stresses, it is also involved in at least two critical processes whose activity is essential in preventing Parkinson's disease (PD) pathology. Actually, hsc70 protein acts as the main carrier of chaperone-mediated autophagy (CMA), a selective catabolic pathway for alpha-synuclein, the main pathogenic protein that accumulates in degenerating dopaminergic neurons in PD. Furthermore, hsc70 efficiently fragments alpha-synuclein fibrils in vitro and promotes depolymerization into non-toxic alpha-synuclein monomers. Considering that the mitochondrial complex I inhibitor rotenone, used to generate PD animal models, induces alpha-synuclein aggregation, this study was designed in order to verify whether rotenone exposure leads to hsc70 alteration possibly contributing to alpha-synuclein aggregation. To this aim, human SH-SY5Y neuroblastoma cells were treated with rotenone and hsc70 mRNA and protein expression were assessed; the effect of rotenone on hsc70 was compared with that exerted by hydrogen peroxide, a generic oxidative stress donor with no inhibitory activity on mitochondrial complex I. Furthermore, the effect of rotenone on hsc70 was verified in primary mouse cortical neurons. The possible contribution of macroautophagy to rotenone-induced hsc70 modulation was explored and the influence of hsc70 gene silencing on neurotoxicity was assessed. We demonstrated that rotenone, but not hydrogen peroxide, induced a significant reduction of hsc70 mRNA and protein expression. We also observed that the toxic effect of rotenone on alpha-synuclein levels was amplified when macroautophagy was inhibited, although rotenone-induced hsc70 reduction was independent from macroautophagy. Finally, we demonstrated that hsc70 gene silencing up-regulated alpha-synuclein mRNA and protein levels without affecting cell viability and without altering rotenone- and hydrogen peroxide-induced cytotoxicity. These findings demonstrate the existence of a novel mechanism of rotenone toxicity mediated by hsc70 and indicate that dysfunction of both CMA and macroautophagy can synergistically exacerbate alpha-synuclein toxicity, suggesting that hsc70 up-regulation may represent a valuable therapeutic strategy for PD.

Several lines of evidence implicate a central role for alpha-synuclein (aSN) in the pathogenesis of Parkinson's disease (PD). Besides rare genetic mutations, post-translational mechanisms, such as oxidative stress-related nitration, may alter the protein properties in terms of propensity to aggregate or be degraded. Our group previously described increased reactive oxygen species (ROS) production within easily accessible peripheral blood mononuclear cells (PBMCs) in PD patients compared to healthy elderly subjects. In the present work, we demonstrated a significant induction of nitrotyrosine (NT)-modifications of aSN within PBMCs derived from individuals with idiopathic PD compared to controls, while aSN protein appeared similarly expressed in the two populations. The amount of NT-modified aSN within PBMCs was positively correlated with intracellular ROS concentration and inversely related to daily dosage of levodopa, making its measurement potentially relevant for disease-intervention studies. Neither aSN expression nor its NT-modifications showed any correlation to specific REP1 genotypes, polymorphic variants within aSN gene promoter whose association to PD susceptibility may occur through the modulation of aSN protein expression. Moreover, although NT-modified aSN has been linked to enhanced propensity to aggregate, we failed to detect an increased presence of insoluble aSN aggregates in PBMCs from PD subjects relative to controls, despite a lack of changes in the ubiquitin-proteasome expression or activity. Nonetheless, a significant activation of the autophagy response was identified within PBMCs from PD individuals, which could represent a protective mechanism against abnormal protein accumulation and may explain the lack of aSN aggregation. We discuss the relevance of these findings with respect to PD pathogenesis and biomarker development.

Three elderly patients with, respectively: mild cognitive impairment, severe and progressive neurologic involvement, and focal neurologic deficit, were observed. MRI showed multiple areas of white matter edema, at times partially involving the cortex, in the first two patients, and a single area in the third. Treatment with steroids determined the disappearance of the lesions and clinical amelioration. The key to the diagnosis of cerebral amyloid angiopathy-related inflammation (CAA-ri) was the demonstration, with appropriate MRI sequences, of microbleeds consistent with cerebral amyloid angiopathy (CAA). This diagnosis was supported by genetic analysis of APOE with demonstration of ε4/ε4 genotype, found in about 80% of CAA patients who develop inflammatory changes. In the appropriate clinical setting, MRI demonstration of microbleeds supported by results of genetic analysis of APOE may strongly support the diagnosis of CAA-ri thus avoiding cerebral biopsy.

Oxidative stress, resulting from the imbalance between reactive oxygen species (ROS) formation and antioxidant defenses, plays a major role in the pathogenesis of Parkinson's disease (PD). However, the contribution of levodopa (LD) therapy to oxidative damage is still debated. We investigated oxidative stress in peripheral blood mononuclear cells (PBMCs) from LD-treated PD patients and healthy subjects. Increased ROS production associated with unaltered glutathione reductase activity was detected in PBMC from PD patients. LD daily dosage appeared to be inversely correlated with ROS levels and positively associated with GR activity, suggesting a protective role for LD on PBMCs redox status. Our data support the view of systemic oxidative stress involvement in PD and give further rationale for using PBMCs as an easily accessible ex-vivo dopaminergic model for exploring the biological effects of LD therapy.

Altered glutamate transport and aberrant EAAT1 expression were shown in Alzheimer’s disease (AD) brains. It is presently unknown whether these modifications are a consequence of neurodegeneration or play a pathogenetic role. However, recent findings of decreased glutamate uptake, EAAT1 protein and mRNA in AD platelets suggest that glutamate transporter modifications may be systemic and might explain the decreased glutamate uptake. We now used primary fibroblast cultures from 10 AD patients to further investigate the specific involvement of glutamate transporters in this disorder and in normal aging. Decreased glutamate uptake (p < 0.001), EAAT1 expression (p < 0.05) and mRNA (p < 0.01) were observed in aged people, compared to younger controls. In AD fibroblasts, compared to age-matched controls, we observed further reductions of glutamate uptake (p < 0.0005) and EAAT1 expression (p < 0.005), while EAAT1 mRNA increase (p < 0.001) was shown. EAAT1 parameters were mutually correlated (p < 0.01) and correlations were shown with dementia severity (p < 0.05 MMSE-expression, p < 0.005 MMSE-mRNA). We suggest fibroblast cultures as possible ex vivo peripheral model to study the glutamate involvement and possible molecular and therapeutic targets in AD.

The metabolic processing of GM1 ganglioside, exogenously administered to cultured skin fibroblasts, was investigated on cells obtained from patients affected with Alzheimer disease, in comparison with age-matched control subjects. Cultured fibroblasts were incubated with GM1 ganglioside, [(3)H]-radiolabelled at the sphingosine moiety. It was observed that the extent of tritiated GM2 and GM3 ganglioside formation was higher in AD fibroblasts than in control cells. The activity of acidic beta-D-galactosidase, responsible of GM1 hydrolysis to GM2 within lysosomes, assayed in vitro on cell lysates, was increased in AD fibroblasts in comparison with control cells. These data suggest that up-regulation of lysosomal enzymes could be responsible of the enhanced GM1 catabolism in AD fibroblasts. Finally, it was found that the extent of GM1 hydrolysis in AD fibroblasts was inversely correlated with the mini-mental score index of patients. The increased hydrolysis rate of sphingolipids could be taken as peripheral hallmark of Alzheimer's disease patients.

Familial amyloidotic polyneuropathy is a rare autosomal dominant disease, with clinical symptoms beginning in most kindreds within the third to seventh decades of life. The primary defect results from one of a number of mutations in the transthyretin (TTR) gene. Over 80 mutations in the TTR gene have been described. Most mutations give rise to adult onset progressive peripheral and autonomic neuropathy, due to amyloid deposition within the nerves, and often subclinical cardiac amyloid and vitreous deposits. We report here the clinical and molecular characterization of a rare TTR missense mutation discovered in a young woman from Macedonia, showing severe axonal sensory-motor polyneuropathy, restrictive cardiomyopathy and bilateral vitreous deposits. The transthyretin gene, analyzed by direct nucleotide sequencing, demonstrated a T to G transversion at nucleotide 183 in the exon 2 which is predicted to cause a heterozygous valine for phenylalanine substitution at codon 33 (TTR Phe33Val). This mutation has been previously reported only twice, without complete clinical descriptions.

Extensive CSF and blood tests were normal except for elevated serum alpha-fetoprotein (AFP) levels (25 ng/l, n.v. 7 ng/l). Nerve conduction stud-ies showed a motor axonal neuropathy; needle EMG examination demonstrated diffuse fi brillations and enlarged polyphasic action potentials in limb and bulbar muscles. MRI studies revealed slight wide-spread supratentorial atrophy and marked thinning of the cervical spinal cord predominantly involving the C4 – C5 segments, without signal abnormalities (Figure 1A). Cerebral FDG-PET showed mild hypo-metabolism of frontoparietal and anterior temporal lobes, with subtle signs of frontal dysfunction at neu-ropsychological evaluation. The patient died from respiratory failure two years after fi rst examination. No autopsy could be performed. Over the disease course, genetic testing for HD, DRPLA, FRDA1, SCA1-2-7-17 and FALS-related genes (

The best validated susceptibility variants for Parkinson's disease are located in the α-synuclein (SNCA) and microtubule-associated protein tau (MAPT) genes. Recently, a protective p.N551K-R1398H-K1423K haplotype in the leucine-rich repeat kinase 2 (LRRK2) gene was identified, with p.R1398H appearing to be the most likely functional variant. To date, the consistency of the protective effect of LRRK2 p.R1398H across MAPT and SNCA variant genotypes has not been assessed. To address this, we examined 4 SNCA variants (rs181489, rs356219, rs11931074, and rs2583988), the MAPT H1-haplotypedefining variant rs1052553, and LRRK2 p.R1398H (rs7133914) in Caucasian (n = 10,322) and Asian (n = 2289) series. There was no evidence of an interaction of LRRK2 p.R1398H with MAPT or SNCA variants (all p ≥ 0.10); the protective effect of p.R1398H was observed at similar magnitude across MAPT and SNCA genotypes, and the risk effects of MAPT and SNCA variants were observed consistently for LRRK2 p.R1398H genotypes. Our results indicate that the association of LRRK2 p.R1398H with Parkinson's disease is independent of SNCA and MAPT variants, and vice versa, in Caucasian and Asian populations.

Background: Despite recent development of direct acting antivirals for treatment of hepatitis C, the current standard of care may still include pegylated-interferon, which is associated with frequent and, at times, serious adverse events. Case presentation: Here we report for the first time on a severe case of classic neuromyelitis optica (i.e., optic-spinal form) in a 32 year-old Egyptian man with chronic hepatitis C treated with pegylated-interferon α2a for 4 months. Conclusions: Treating physicians must be alerted on rare but important unexpected complications of interferon, in order to consider carefully its use especially when they deal with patients not in dire need of urgent treatment.

Objectives: The objective of this study is to clarify the role of (G 4 C 2 ) n expansions in the etiology of Parkinson disease (PD) in the worldwide multicenter Genetic Epidemiology of Parkinson9s Disease (GEO-PD) cohort. Methods: C9orf72 (G 4 C 2 ) n repeats were assessed in a GEO-PD cohort of 7,494 patients diagnosed with PD and 5,886 neurologically healthy control individuals ascertained in Europe, Asia, North America, and Australia. Results: A pathogenic (G 4 C 2 ) n>60 expansion was detected in only 4 patients with PD (4/7,232; 0.055%), all with a positive family history of neurodegenerative dementia, amyotrophic lateral sclerosis, or atypical parkinsonism, while no carriers were detected with typical sporadic or familial PD. Meta-analysis revealed a small increase in risk of PD with an increasing number of (G 4 C 2 ) n repeats; however, we could not detect a robust association between the C9orf72 (G 4 C 2 ) n repeat and PD, and the population attributable risk was low. Conclusions: Together, these findings indicate that expansions in C9orf72 do not have a major role in the pathogenesis of PD. Testing for C9orf72 repeat expansions should only be considered in patients with PD who have overt symptoms of frontotemporal lobar degeneration/amyotrophic lateral sclerosis or apparent family history of neurodegenerative dementia or motor neuron disease.

Chaperone-mediated autophagy (CMA) impairment is recognized to play a pathogenetic role in Parkinson's disease (PD). A reduced expression of lysosomal-associated membrane protein (lamp) 2A and heat shock cognate (hsc) 70 protein, the two key regulators of CMA, has been reported in brains of PD patients. To verify the existence of a possible systemic CMA dysfunction in PD, in this study the expression of hsc70 and lamp2A was assessed in peripheral blood mononuclear cells (PBMC) of patients with sporadic PD and compared to healthy subjects. The expression of myocyte enhancer factor 2D (MEF2D), a transcriptional factor implicated in neuronal survival and specific substrate of CMA, was also evaluated. Protein and gene expression was assessed by Western blot and real-time PCR, respectively, in PBMC obtained from 53 sporadic PD patients and 53 healthy subjects. A significant reduction of hsc70 levels was observed in PBMC of PD patients, both under basal conditions and after autophagy induction obtained with serum deprivation. No difference emerged in lamp2A and MEF2D expression between patients and controls. No influence of the clinical characteristics of patients emerged on hsc70, lamp2A and MEF2D expression. These results, despite being not suggestive of the existence of a CMA impairment in PBMC of PD patients, identify a systemic hsc70 reduction in PD patients. Further studies on specific mechanisms and biological significance of such alteration are needed to corroborate this finding that could lead to the identification of a new trait biomarker for PD.

Generation of reactive oxygen species during dopamine (DA) oxidation could be one of the factors leading to the selective loss of nigral dopaminergic neurons in Parkinson’s disease (PD). Vesicular monoamine transporter type 2 (VMAT2) proteins in nerve terminals uptake dopamine into synaptic vesicles, preventing its cytoplasmic accumulation and toxic damage to nigral neurons. Polymorphisms in VMAT2 gene and in its regulatory regions might therefore serve as genetic risk factors for PD. In the present study, we have analyzed 8 single-nucleotide polymorphisms (SNPs) located within/around the VMAT2 gene for association with PD in an Italian cohort composed of 704 PD patients and 678 healthy controls. Among the 8 SNPs studied, only the 2 located within the promoter region (rs363371 and rs363324) were significantly associated with PD. In the dominant model, odds ratios were 0.72 (95% confidence interval [CI]: 0.6–0.9, p < 0.005) for rs363371 and 0.76 (95% CI: 0.6–0.9, p = 0.01) for rs363324; in the additive model, odds ratios were 0.78 (95% CI: 0.65–0.94, p = 0.008) for rs363371 and 0.85 (95% CI: 0.7–20.92, p = 0.04) for rs363324. There were no significant relationships between the remaining SNPs (rs363333, rs363399, rs363387, rs363343, rs4752045, and rs363236) and the risk of sporadic PD in any genetic model. This study adds to the previous evidence suggesting that variability in VMAT2 promoter region may confer a reduced risk of developing PD, presumably via mechanisms of gene overexpression.

Dysfunctions of chaperone-mediated autophagy (CMA), the main catabolic pathway for alpha-synuclein, have been linked to the pathogenesis of Parkinson’s disease (PD). Since till now there is limited information on how PD-related toxins may affect CMA, in this study we explored the effect of mitochondrial complex I inhibitor rotenone on CMA substrates, alpha-synuclein and MEF2D, and effectors, lamp2A and hsc70, in a human dopaminergic neuroblastoma SH-SY5Y cell line. Rotenone induced an upregulation of alpha-synuclein and MEF2D protein levels through the stimulation of theirde novosynthesis rather than through a reduction of their CMA-mediated degradation. Moreover, increased MEF2D transcription resulted in higher nuclear protein levels that exert a protective role against mitochondrial dysfunction and oxidative stress. These results were compared with those obtained after lysosome inhibition with ammonium chloride. As expected, this toxin induced the cytosolic accumulation of both alpha-synuclein and MEF2D proteins, as the result of the inhibition of their lysosome-mediated degradation, while, differently from rotenone, ammonium chloride decreased MEF2D nuclear levels through the downregulation of its transcription, thus reducing its protective function. These results highlight that rotenone affects alpha-synuclein and MEF2D protein levels through a mechanism independent from lysosomal degradation inhibition.

The molecular mechanisms of neurodegeneration in Parkinson’s disease and the cause of the selective dopaminergic neuronal loss are mostly unknown. Many pathogenetic factors have been found to play a role but the relationships among these factors, together with the reasons of the high vulnerability of dopaminergic neurons to them, have not been completely defined. Only a small fraction of Parkinson’s disease cases have a defined etiology: this fraction include the monogenic hereditary variants of the disease and the sporadic cases determined by prolonged exposition to toxic agents inhibiting mitochondrial complex I, such as 1,1’-dimethyl-4,4’-5 bipyridinium (paraquat), rotenone and 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine (MPTP). Parkinson’s disease-related toxins and pathogenetic mutations have been indispensable to create cell and animal models with the aim to clarify the molecular physiopathology of the disease. Little is known about the primitive causes of idiopathic Parkinson’s disease, that probably represents a multi-factorial disease influenced by various genetic and environmental factors, all characterized by high incidence in general population. The different risk factors together would contribute to initiate the complex pathogenetic sequence of events leading to the death of dopaminergic neurons. Recently, Parkinson’s disease has been placed in the large category of neurodegenerative diseases caused by protein misfolding. In particular, alpha-synuclein has been proposed as the central and most specific factor implied in the pathogenesis of this syndrome, which, as a consequence, has been classified among synucleinopathies, together with dementia with Lewy bodies and multiple system atrophy, other neurodegenerative diseases having alphasynuclein pathology as a major feature. Aim of this chapter is to provide an organic revision of evidences for the involvement of alpha-synuclein in the pathogenesis of Parkinson’s disease. We will define the mechanisms responsible for the toxic gain of function of ┙-synuclein and the processes triggered by aberrant alpha-synuclein and mediating its neurotoxic effect. Particular attention will be paid to establish the links that correlate the deleterious action of alpha-synuclein with oxidative stress and with the efficiency of the processes involved in the clearance of aberrant

A 68-year-old man presented with a 4-month history of progressive memory loss and mood disorders. Neurologic examination revealed severe impairment of attention and verbal skills, without motor and sensory deficits. His medical history included mild arterial hypertension, idiopathic partial epilepsy, and obsessive compulsive disorder. Brain MRI showed the presence of bilateral, asymmetric, swollen white matter lesions in the cerebral hemispheres, hyperintense in T2-weighted images, that partially involved the left frontal cortex (figure). On diffusion-weighted sequences, the white matter abnormalities were consistent with vasogenic edema. No pathologic contrast enhancement was present. Figure MRI of cerebral amyloid angiopathy–related inflammation (CAA-ri) and levels of anti-Aβ 1-40 and 1-42 autoantibodies in the CSF Axial fluid-attenuated inversion recovery brain MRI shows bilateral hyperintense lesions of the subcortical white matter (A), which are reduced after 20 days of steroid treatment (B). Axial T2*-weighted gradient-echo MRI (C) obtained 33 days later shows further reduction of white matter lesions and multiple, scattered, hypointense cortical lesions due to microhemorrhages (arrows). (D) Reiber's graph. X- and y-axes show, respectively, albumin (QAlb) and immunoglobulin G quotient (QIgG), obtained by the ratio between the level of the protein in the CSF from the first lumbar puncture and in the plasma. The QAlb indicates the permeability of the blood–brain barrier (BBB) to water-soluble molecules. The QIgG (total IgG including specific anti-Aβ autoantibodies) plotted into the graph discriminates between intrathecal production of IgG and …

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is often related to the A3243G mutation of the mitochondrial DNA, accounting for about 80% of typical cases, with a relevant phenotypic variability. Hemorrhagic strokes are quite unusual in these patients. A case of recurrent brain hematomas has been reported in a MELAS patient carrying the G13513A mutation, with clinical onset at age 31 [1]. Another fatal case of intracerebral hemorrhage was reported in a MERRF/MELAS overlap syndrome due to a T8356C mutation [2]. Finally, a putaminal hemorrhagic stroke was described in a MERRF patient carrying the A8344G mutation, with clinical onset at age 26 [3]. Here, we report the case of a 37-year-old male arriving to our attention because of a two-week history of headache associated with nausea, vomiting, and dizziness. A brain MRI scan showed a left hemispheric cerebellar hemorrhage at a stage compatible with the onset of the symptoms. The patient neither had history of arterial hypertension, any hemorrhagic risk-factor, diabetes, nor was taking any medication. A few years before, he was found to be asymptomatic carrier of the A3243G mitochondrial DNA mutation (heteroplasmy confirmed on a blood sample), since a MELAS diagnosis was made on his younger brother expressing a typical phenotype. On current examination, our patient presented slight left ataxic hemiparesis and hypoesthesia. A cerebral angiography failed to show any vascular abnormality. Since our patient was carrier of a MELAS mutation, we decided to assess its putative clinical burden. An EEG showed generalized electrogenetic dysfunction with a single generalized epileptic spike discharge; EMG suggested slight myopathic signs; mild perceptive bilateral deafness was also present. A venous lactic acid test with compression of the right arm was significant (baseline values 2.9 mmol/L; increase up to 7.5 mmol/L after 3 min; NV 0.44–2.22 mmol/L). No hearth conduction defects were present. A week later, on a control CT scan, progressive blood reabsorption was noted and basal ganglia calcifications were not observed; the headache had improved and the neurological examination was normal. Iizuka et al. [4] demonstrated cortical laminar necrosis and focal HMPAO SPET hyperperfusion during subacute stages of stroke-like episodes; moreover, they reported several cases of microhemorrhages and at least one case of intracortical gyral hemorrhage, suggesting that stroke-like episodes are characterized by increased capillary permeability and focal hyperemia [5]. Consistently, vasogenic edema has been reported during stroke-like episodes [6]. Anyhow, in our case, the aspect of the lesion does not suggest the hemorrhagic transformation of a stroke-like episode; this also considering that the hematoma was confined in a specific vascular territory, which is not a characteristic of stroke-like episodes [4]. Conversely, we cannot exclude a hemorrhagic coincidental event in a patient carrying the A3243G mutation with a subclinical MELAS phenotype. However, mitochondrial angiopathy in E. Saracchi L. Tremolizzo J. C. DiFrancesco L. Brighina G. Costantino B. Frigeni M. Brioschi M. L. Piatti L. Fumagalli L. Marzorati N. A. Curto C. Ferrarese Department of Neurology, S. Gerardo Hospital, Monza, Italy

Despite advances in neuroimaging, the diagnosis of idiopathic Parkinson's disease (PD) remains clinical. The identification of biological markers for an early diagnosis is of great interest to start a neuroprotective therapy aimed at slowing, blocking or reversing the disease progression. Vesicular monoamine transporter 2 (VMAT2) sequesters cytoplasmic dopamine into synaptic vesicles for storage and release. Thus, VMAT2 impairment can regulate intra- and extracellular dopamine levels, influencing oxidative stress and neuronal death. Because in vivo imaging studies have demonstrated a VMAT2 reduction in PD patients greater than would be explained by neuronal loss alone, as an exploratory study we assessed VMAT2 mRNA and protein levels in platelets from 39 PD patients, 39 healthy subjects and 10 patients with vascular parkinsonism (VP) to identify a possible peripheral biomarker for PD. A significant reduction (p < 0.05) of VMAT2 mRNA levels was demonstrated in PD patients versus healthy controls. Patients with VP showed VMAT2 mRNA levels similar to controls. No difference in VMAT2 mRNA levels was found in untreated versus treated patients. No correlation was observed between mRNA levels and demographic or clinical characteristics. Furthermore, eight SNPs tagging the VMAT2 gene did not show effects on VMAT2 mRNA levels. Western blot analysis did not allow the quantification of VMAT2 protein expression in blood platelets. Although further studies in a greater number of cases are needed to confirm our data, the reduction in VMAT2 mRNA in platelets from PD patients suggests the existence of a systemic impairment of this transporter possibly contributing to PD pathology.

Early genome-wide association (GWA) studies on Parkinson's disease (PD) have not been able to yield conclusive, replicable signals of association, perhaps due to limited sample size. We aimed to investigate whether association signals derived from the meta-analysis of the first two GWA investigations might be replicable in different populations. We examined six single-nucleotide polymorphisms (SNPs) (rs1000291, rs1865997, rs2241743, rs2282048, rs2313982, and rs3018626) that had reached nominal significance with at least two of three different strategies proposed in a previous analysis of the original GWA studies. Investigators from the "Genetic Epidemiology of Parkinson's Disease" (GEOPD) consortium were invited to join in this study. Ten teams contributed replication data from 3,458 PD cases and 3,719 controls. The data from the two previously published GWAs (599 PD cases, 592 controls and 443 sibling pairs) were considered as well. All data were synthesized using both fixed and random effects models. The summary allelic odds ratios were ranging from 0.97 to 1.09 by random effects, when all data were included. The summary estimates of the replication data sets (excluding the original GWA data) were very close to 1.00 (range 0.98-1.09) and none of the effects were nominally statistically significant. The replication data sets had significantly different results than the GWA data. Our data do not support evidence that any of these six SNPs reflect susceptibility markers for PD. Much stronger signals of statistical significance in GWA platforms are needed to have substantial chances of replication. Specifically in PD genetics, this would require much larger GWA studies and perhaps novel analytical techniques. (C) 2009 Wiley-Liss, Inc. American Journal of Medical Genetics Part B-Neuropsychiatric Genetics

In this study we employed an ELISA assay to measure alpha-synuclein protein in lymphomonocytes from 78 PD patients and 78 controls. We correlated protein levels with demographic and clinical characteristics and with the chymotryptic and tryptic activities of the 20S proteasome. Alpha-synuclein levels were not significantly different between patients and controls. In control subjects, alpha-synuclein protein levels increased significantly with age and were significantly higher in men compared to women. Proteasome activity was not significantly different between cases and controls. In control group, the 20S chymotryptic activity tended to decrease significantly with increasing age, though it was not correlated to alpha-synuclein levels. The 20S tryptic activity was not significantly correlated to age, but was inversely correlated to alpha-synuclein levels. Our findings suggest that alpha-synuclein levels in lymphomonocytes are affected by age, gender, and by the 20S proteasome activity in control subjects, but they are not useful as a diagnostic biomarker for PD.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder involving both upper and lower motor neurons, leading inexorably to death within a few years. Although our understanding of the pathogenesis of this disease has grown at a very fast rate in recent years, we do not yet have effective treatment options that can positively impact the quality of life (QoL) of these patients. Interestingly, increasing experimental evidence suggests that oxidative stress is involved in the pathogenesis of ALS and that vitamin E could reduce neuronal damage. Hence, in this observational study we determined the QoL in 33 ALS patients taking or not taking vitamin E supplementation (600 mg/day), using the Italian version of the Short-Form 36-Item Health Survey (SF-36). No differences were seen between the two groups of patients, therefore we do not recommend routine use of vitamin E in ALS patients, at least in the absence of randomised clinical trials specifically designed for addressing this issue.

Oxidative stress has been demonstrated in Alzheimer's disease (AD) brain and may affect glutamate transport (GT), thereby leading to excitotoxic neuronal death. Since oxidative stress markers have been shown also in peripheral tissues, we investigated possible GT alterations in fibroblast cultures obtained from 18 patients with AD and 15 control patients and analyzed the effects of the lipoperoxidation product 4-hydroxynonenal (4-HNE) and antioxidants. Basal GT was decreased by 60% in fibroblasts from patients with AD versus control patients. Exposure to HNE did not affect GT in control patients, but it reduced GT by 50% in patients with AD, without any concomitant change in cell viability; conversely, HNE exposure induced a larger increase in ROS intracellular levels in AD than in control fibroblasts. Glutathione and N-acetylcysteine completely blocked 4-HNE effects and also increased basal uptake in AD cells. Moreover, inhibition of glutathione synthesis in control fibroblasts by pretreatment with buthionine sulfoximine resulted in GT reduction (40%) and an increase in ROS levels after exposure to 4-HNE. Nevertheless, since there are no differences between GSH basal level in controls and patients with AD, the alteration of other antioxidant systems cannot be excluded. Our study supports the hypothesis of a systemic impairment of GT in AD, possibly linked to oxidative stress and to reduced antioxidant defenses, which may be partially reversed by antioxidant treatment. Therefore, we suggest fibroblast cultures as a tool for exploring pathogenetic mechanisms and possible therapeutic strategies in patients with AD. (C) 2004 Elsevier Inc. All rights reserved.

Overexpression of APP and SOD induces beta-amyloid deposition and oxidative stress in Down syndrome (DS) patients. Both phenomena may impair glutamate transport and decreased glutamate uptake sites have been demonstrated in patient brains at autopsy. Since alterations of APP metabolism and oxidative damage are systemic, we investigated glutamate uptake in platelets and fibroblasts from DS patients to explore whether abnormalities in this process are inherent properties of DS cells and not secondary to neurodegeneration. Glutamate uptake was significantly decreased in platelets (P

Genetic risk factors seem to play a role in sporadic Parkinson's disease (PD), maybe triggering oxidative stress and excitotoxicity within substantia nigra. However, genetic factors act at systemic level: reduced activity of mitochondrial enzymes and decreased glutamate uptake have been shown in platelets from PD patients. In this study we investigated glutamate uptake in platelets from 38 sporadic PD patients, 13 patients with parkinsonian syndromes and 28 controls and assessed polymorphisms of alpha -synuclein and ApoE genes. A 48% reduction of glutamate uptake (p