Serum DBI and biomarkers of neuroinflammation in Alzheimer's disease and delirium.

BACKGROUND: Alzheimer's disease (AD) patients often express significant behavioral symptoms: for this reason, accessible related biomarkers could be very useful. Neuroinflammation is a key pathogenic process in both AD and delirium (DEL), a clinical condition with behavioral symptoms resembling those of AD. METHODS: A total of n = 30 AD patients were recruited together with n = 30 DEL patients and n = 15 healthy controls (CTRL). Serum diazepam binding inhibitor (DBI), IL-17, IL-6, and TNF-α were assessed by ELISA. RESULTS: DBI serum levels were increased in AD patients with respect to CTRL (+ 81%), while DEL values were 70% higher than AD. IL-17 was increased in DEL with respect to CTRL (+ 146%), while AD showed dispersed values and failed to reach significant differences. On the other hand, IL-6 showed a more robust increase in DEL with respect to the other two groups (+ 185% and + 205% vs. CTRL and AD, respectively), and TNF-α failed to show any change. CONCLUSIONS: DBI may be a very promising candidate for AD, perhaps marking psychomotor DEL-like symptoms, in view of developing future helping tool for practicing physicians. Furthermore, DBI rise in DEL offers novel cues for a better comprehension of the pathogenesis of this potentially fatal condition.

TREX1 C-terminal frameshift mutations in the systemic variant of retinal vasculopathy with cerebral leukodystrophy.

Retinal vasculopathy with cerebral leukodystrophy (RVCL) is an adult-onset disorder caused by C-terminal heterozygous frameshift (fs) mutations in the human 3'-5' DNA exonuclease TREX1. Hereditary systemic angiopathy (HSA) is considered a variant of RVCL with systemic involvement of unknown genetic cause, described in a unique family so far. Here we describe the second case of RVCL with systemic involvement, characterized by cerebral calcifications and pseudotumoral lesions, retinopathy, osteonecrosis, renal and hepatic failure. The genetic screening of TREX1 in this patient revealed the novel heterozygous T270fs mutation on the C-terminal region. On the same gene, we found the V235fs mutation, formerly shown in RVCL, in one patient previously reported with HSA. These mutations lead to important alterations of the C-terminal of the protein, with the loss of the transmembrane helix (T270fs) and the insertion of a premature stop codon, resulting in a truncated protein (V235fs). Functional analysis of T270fs-mutated fibroblasts showed a prevalent localization of the protein in the cytosol, rather than in the perinuclear region. RVCL with systemic involvement is an extremely rare condition, whose diagnosis is complex due to multiorgan manifestations, unusual radiological and histopathological findings, not easily attributable to a single disease. It should be suspected in young adults with systemic microangiopathy involving retina, liver, kidney, bones and brain. Here we confirm the causative role played by TREX1 autosomal dominant fs mutations disrupting the C-terminal of the protein, providing a model for the study of stroke in young adults.

Lack of evidence for oxidative stress in sporadic amyotrophic lateral sclerosis fibroblasts.

BACKGROUND: It is conceivable that an early therapeutic intervention in amyotrophic lateral sclerosis (ALS) would lead to better results in terms of disease progression for these patients. One possible strategy to increase the sensitivity of the diagnosis is represented by the use of biological parameters reflecting, for example, oxidative stress alterations associated with ALS. Such biomarkers would be valuable tools both for a better diagnostic evaluation and for studying the impact of therapeutic interventions on the disease course. A special category of experimental models is represented by peripheral cells obtained directly from patients (ex vivo). OBJECTIVE: In this study, primary fibroblasts obtained from 10 sporadic ALS (SALS) patients and 10 healthy matched controls were used to investigate a panel of parameters related to the oxidative status. METHODS: Reactive oxygen species production, protein carbonylation and nitration, susceptibility to hydrogen peroxide exposure, p38-mitogen-activated protein kinase activation and adenosine triphosphate intracellular content were evaluated. RESULTS: No significant difference was observed in all investigated parameters between patient and control cells, and no correlation with the disease severity was found. CONCLUSION: Collectively, our data show no major alterations of the oxidative and bioenergetic status in SALS cultured fibroblasts, suggesting that these cells do not represent a useful model to study the oxidative dysfunction associated with SALS.

Oxidative stress impairs glutamate uptake in fibroblasts from patients with Alzheimer's disease.

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.

Altered glutamate uptake in peripheral tissues from Down syndrome patients.

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<0.005 vs. control) and fibroblasts (P<0.001 vs. control) from DS patients, particularly in those with free trisomy and with mitochondrial point mutations. Systemic impairment of glutamate uptake in DS is suggested, probably related to APP overexpression and mitochondrial dysfunction. Such mechanisms may contribute to neurodegeneration and dementia development in these patients.

Quantitative detection of epstein-barr virus DNA in cerebrospinal fluid and blood samples of patients with relapsing-remitting multiple sclerosis.

The presence of Epstein-Barr Virus (EBV) DNA in cerebrospinal fluid (CSF) and peripheral blood (PB) samples collected from 55 patients with clinical and radiologically-active relapsing-remitting MS (RRMS) and 51 subjects with other neurological diseases was determined using standardized commercially available kits for viral nucleic acid extraction and quantitative EBV DNA detection. Both cell-free and cell-associated CSF and PB fractions were analyzed, to distinguish latent from lytic EBV infection. EBV DNA was detected in 5.5% and 18.2% of cell-free and cell-associated CSF fractions of patients with RRMS as compared to 7.8% and 7.8% of controls; plasma and peripheral blood mononuclear cells (PBMC) positivity rates were 7.3% and 47.3% versus 5.8% and 31.4%, respectively. No significant difference in median EBV viral loads of positive samples was found between RRMS and control patients in all tested samples. Absence of statistically significant differences in EBV positivity rates between RRMS and control patients, despite the use of highly sensitive standardized methods, points to the lack of association between EBV and MS disease activity.

Alpha-synuclein nitration and autophagy response are induced in peripheral blood cells from patients with Parkinson disease.

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.

Lymphomonocyte alpha-synuclein levels in aging and in Parkinson disease.

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.

Neuroligand binding endophenotypes in blood cells distinguish two subsets of borderline personality disorder patients.

Neurotransmitter ligand binding in blood cells was assessed in borderline personality disorder (BDP) patients, testing the possibility that different biochemical endophenotypes might lie beneath a specific clinical presentation. The density of peripheral benzodiazepine receptors (PBR) and serotonin transporters were assessed in peripheral blood mononuclear cells (PBMC) and platelets, respectively, showing a decrease of both parameters. Moreover, a further significant decrease of PBR in PBMC was shown for those patients with a depressive trait. Further confirmation of the presence of different molecular endophenotypes underlying the dissimilar clinical presentations in BPD may advance our possibility of successfully treating these patients.

Oxidative stress in peripheral blood mononuclear cells from patients with Parkinson's disease: negative correlation with levodopa dosage.

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.