Elisa Conti

Whole-blood global DNA methylation is increased in amyotrophic lateral sclerosis independently of age of onset

Abstract ALS is a heterogeneous disease that is not well understood. Epigenetic rearrangements are important in complex disorders including motor neuron diseases. The aim of this study was to determine whether whole-blood DNA methylation (DNA MET %) is a potential modifier of age at onset in ALS. DNA MET % was measured as incorporation of [3H]dCTP following HpaII cut in 96 ALS patients and 87 controls, comprising: early-onset (< 55 years of age) and late-onset (> 74 years of age). Methionine (Met) and homocysteine (Hcy) plasma levels were assessed by liquid chromatography selected reaction monitoring coupled with isotope-dilution mass spectrometry. Results showed that DNA MET % was increased in ALS patients independently of age of onset. Compared to the other three groups, Hcy plasma levels were reduced in early-onset ALS patients but Met levels were similar. ROC analysis reported Met levels and DNA MET %, respectively, with a slight and moderate discriminative power. In conclusion, increased DNA MET % is a possible marker of epigenetic dysfunction in ALS independently of age of onset. Further studies dissecting biological determinants of phenotypic complexity in ALS may help in developing successful therapeutic strategies.

Increased Soluble APPα, Abeta 1-42, and Anti-Abeta 1-42 Antibodies in Plasma From Down Syndrome Patients

Down syndrome (DS) is the most common genetic disorder characterized by an extra copy of chromosome 21. DS subjects show signs of progressive cognitive decline, and most of them develop Alzheimers type dementia at the age of 50 to 55 years. The aim of this study was to evaluate amyloid precursor protein (APP) metabolites and anti-Abeta 1-42 antibodies plasma levels in DS as possible biomarkers of Abeta accumulation potentially leading to neurodegeneration. We investigated plasma levels of sAPPα, Abeta 1-42, and anti-Abeta 1-42 antibodies by enzyme-linked immunosorbent assay in 24 DS subjects, 10 non-DS mentally retarded subjects and 18 age-matched controls. We found that sAPPα levels were about 1.5-fold higher and Abeta 1-42 levels were about 6-fold higher in DS respect to mentally retarded patients and to controls. DS patients showed Abeta 1-42 antibodies levels 4-fold higher than non-DS mentally retarded group and 2-fold higher than controls. Moreover, anti-Abeta 1-42 antibodies levels were inversely correlated with age in DS subjects. Our results suggested sAPPα as a possible peripheral marker for the alteration in APP metabolism in DS and highlighted an alteration in anti-abeta antibodies, for the first time evaluated in plasma from DS subjects.

Increased tissue factor pathway inhibitor and homocysteine in Alzheimer's disease

We investigated the possible involvement of vascular damage in the pathogenesis of Alzheimers disease (AD), by assessment of plasma levels of tissue factor pathway inhibitor (TFPI), a serine protease inhibitor induced by endothelial injury, and homocysteine (Hcy), a known risk factor for cerebrovascular disorders, folate levels were also measured. 110 probable AD, 38 mild cognitive impairment, 31 patients affected by idiopathic Parkinsons disease (without dementia) and 100 healthy controls, who displayed no vascular disorders were enrolled. TFPI and Hcy were significantly higher in AD patients with respect to other groups. The levels of TFPI and Hcy were positively correlated in hyperhomocysteinemic AD and mild cognitive impairment subjects, and were negatively correlated with folate levels. Our findings suggest that an impairment of endothelial function associated with high Hcy levels may occur in AD patients, despite the absence of manifest cerebrovascular lesions. Therefore, TFPI may represent a candidate marker of endothelial damage in AD and might be used for the identification and monitoring of patients that would benefit from folate supplementation treatment.

Post-methionine load test : A more sensitive tool to reveal hyperhomocysteinemia in Alzheimer patients?

OBJECTIVE To identify the real number of hyperhomocysteinemic Alzheimers patients who may benefit from homocysteine-lowering therapy. METHODS Basal and post-methionine load homocysteine levels were assessed by rp-HPLC system. RESULTS PML test revealed twice as many hyperhomocysteinemic AD subjects with respect to the fasting analysis. CONCLUSION PML test resulted useful in detecting higher number of hyperhomocysteinemic AD patients who may have the chance of an early folate treatment.

Valproate induces epigenetic modifications in lymphomonocytes from epileptic patients.

Valproate (VPA) is an anti-epileptic and mood-stabilizing drug with a broad range of action and which mechanism of action still remains in part elusive. Recently the discovery that VPA modifies the epigenome increasing the transcriptional rate of target genes raises the issue of understanding the exact role of this mechanism. In this work we tested the possibility that VPA could modify the epigenome of lymphomonocytes (PBMC) obtained from epileptic patients chronically treated in monotherapy with VPA and phenobarbital. Acetyl-histone H3 expression was assessed by western blotting and global DNA methylation by incorporation of [³H]dCTP. A significant increase in histone acetylation and a correlated decrease of global DNA methylation were shown at VPA therapeutically relevant plasma concentrations. This effect was drug-related, since it was not demonstrated in PBMC obtained from phenobarbital-treated patients. Moreover, a VPA dose-response curve was performed on PBMC obtained from healthy controls, demonstrating an increase of acetyl-histone H3 content. We suggest that the epigenetic properties of VPA expressed on PBMC at these concentrations might be operative in different tissues, with possible implications for the field of neuropsychiatric disorders.

Cholinesterase inhibitor use is associated with increased plasma levels of anti-Abeta 1–42 antibodies in Alzheimer's disease patients

Acetyl-cholinesterase inhibitors (AChEI) are drugs frequently prescribed for the treatment of Alzheimers disease (AD), exerting an effect on cognition, as well as on behavioural and psychological symptoms of dementia and activities of daily living. The efficacy of AChEI may be ascribed not only to the activation of cholinergic transmission, but also to other mechanisms, among which a putative regulation of the immune response has already been hypothesized. In the present study, we evaluated, in a cross-sectional sample of 66AD patients and 48 healthy controls, the putative influence of AChEI on anti-Abeta 1-42 antibody plasma levels by ELISA assay. AD patients receiving AChEI therapy showed increased plasma levels of anti-Abeta 1-42 antibodies respect to untreated AD patients and antibodies levels similar to those of healthy controls, both before and after normalization by total IgG values. Our results support a potential role of AChEI in the modulation of the immune response against Abeta. We suggest that a strategy aimed at increasing the endogenous response against this peptide might represent an interesting therapeutic target to be further investigated.

Reduced fasting plasma levels of diazepam-binding inhibitor in adolescents with anorexia nervosa.

OBJECTIVE Altered expression and/or function, both peripherally and centrally, of various neuropeptides is involved in the neurophysiology of anorexia nervosa (AN). Diazepam-binding inhibitor (DBI) is an interesting peptide for understanding this crosstalk. The aim of this work was to assess fasting plasma levels of DBI and leptin in patients with AN. METHOD Twenty-four AN adolescents were recruited together with 10 age-comparable healthy controls. Neuropeptide determinations were performed on plasma samples by enzyme-linked immunosorbent assays. Patients with AN were further characterized for the presence of a depressive state or anxiety by using, respectively, the Childrens Depression Inventory or the State-Trait Anxiety Inventory form Y. RESULTS Levels of both plasma DBI and leptin were reduced in patients with AN (∼40 and ∼70%, respectively). DBI levels displayed a tendency to increase in the presence of a depressive state, although not with anxiety, whereas leptin levels correlated exclusively with body mass index. DISCUSSION These data further extend our knowledge of neuropeptide dysfunction in AN, and plasma DBI may represent a marker for this disease, in particular considering its correlation with comorbid mood disorders.

BDNF Serum Levels with Respect to Multidimensional Assessment in Amyotrophic Lateral Sclerosis

Background: The clinical presentation of amyotrophic lateral sclerosis (ALS) is characterized by high heterogeneity, the greatest part of which still remains unexplained. Objective: To assess serum levels of brain-derived neurotrophic factor (BDNF) in ALS patients, implementing a multidimensional characterization focused on four a priori chosen elements of phenotypic variability: ALS bulbar/spinal subtype, cognitive impairment, mood dysfunction and disease progression speed. Methods: Serum samples were obtained from 45 ALS outpatients (16% bulbar onset) and 22 healthy controls. Each patient underwent the Montreal Cognitive Assessment (MoCA) and the Beck Depression Inventory (BDI), and disease progression speed was estimated by calculating the decay of the ALSFRS-R score over time. Results: BDNF serum levels did not differ between patients and controls, although ∼25% lower levels characterized those patients carrying a depressive trait. Finally, BDNF serum levels were significantly lower in ALS patients expressing lower ALSFRS-R scores (r = 0.39, p < 0.01). No differences were found when considering cognitive impairment, disease progression speed and site of onset. Conclusion: BDNF serum levels might mark and possibly contribute in part to ALS phenotypic variability.

Multifunctional liposomes interact with Abeta in human biological fluids: Therapeutic implications for Alzheimer's disease

&NA; The accumulation of extracellular amyloid beta (Abeta42) both in brain and in cerebral vessels characterizes Alzheimers disease (AD) pathogenesis. Recently, the possibility to functionalize nanoparticles (NPs) surface with Abeta42 binding molecules, making them suitable tools for reducing Abeta42 burden has been shown effective in models of AD. Aim of this work consisted in proving that NPs might be effective in sequestering Abeta42 in biological fluids, such as CSF and plasma. This demonstration is extremely important considering that these Abeta42 pools are in continuum with the brain parenchyma with drainage of Abeta from interstitial brain tissue to blood vessel and plasma. In this work, liposomes (LIP) were functionalized as previously shown in order to promote high‐affinity Abeta binding, i.e., either with, phosphatidic acid (PA), or a modified Apolipoprotein E‐derived peptide (mApo), or with a curcumin derivative (TREG); Abeta42 levels were determined by ELISA in CSF and plasma samples. mApo‐PA‐LIP (25 and 250 &mgr;M) mildly albeit significantly sequestered Abeta42 proteins in CSF samples obtained from healthy subjects (p < 0.01). Analogously a significant binding (˜20%) of Abeta42 (p < 0.001) was demonstrated following exposure to all functionalized liposomes in plasma samples obtained from selected AD or Downs syndrome patients expressing high levels of Abeta42. The same results were obtained by quantifying Abeta42 content after removal of liposome‐bound Abeta by using gel filtration chromatography or ultracentrifugation on a discontinuous sucrose density gradient. In conclusion, we demonstrate that functionalized liposomes significantly sequester Abeta42 in human biological fluids. These data may be critical for future in vivo administration tests using NPs for promoting sink effect. HighlightsThe use of high affinity Abeta binding liposomes is proposed in human biological fluids.Functionalized liposomes significantly interact with Abeta in plasma and CSF from AD patients.Liposomes may exploit the Abeta “sink effect” as a potential therapeutic strategy.

Novel Therapeutic Targets in Neuropsychiatric Disorders: The Neuroepigenome

The neuroepigenome, i.e., the epigenome of the nervous system, has become interesting for therapeutics in the last years due to widespread availability of dedicated drugs. A pivotal role for neuroepigenetics is certainly implied, both in physiology and pathology, by the highly dynamic structural and functional rearrangements that constantly occur into the nervous system, globally known as plasticity. Moreover, the idea that the pathophysiology of several neuropsychiatric disorders might involve epigenetic mechanisms is increasingly taking place due to accumulating experimental data and by the evidence of a synergistic interaction between genes and environment beneath most sporadic forms of these diseases. In this paper we will review the available evidence on the use of epigenome-modifying drugs in the field of neuropsychiatry, shortly describing for each disease the underlying assumptions of an epigenetic dysregulation.