Marco Onofrj

Pre-analytical factors in clinical proteomics investigations: impact of ex vivo protein modifications for multiple sclerosis biomarker discovery.

Serum proteome investigations have raised an incredible interest in the research of novel molecular biomarker, nevertheless few of the proposed evidences have been translated to the clinical practice. One of the limiting factors has been the lack of generally accepted guidelines for clinical proteomics studies and the lack of a robust analytical and pre-analytical ground for the proposed classification models. Pre-analytical issues may results in a deep impact for biomarker discovery campaign. In this study we present a systematic evaluation of sample storage and sampling conditions for clinical proteomics investigations. We have developed and validated a linear MALDI-TOF-MS protein profiling method to explore the low protein molecular weight region (5-20 kDa) of serum samples. Data normalization and processing was performed using optimise peak detection routine (LIMPIC) able to describe each group under investigation. Data were acquired either from healthy volunteers and from multiple sclerosis patients in order to highlight ex vivo protein profile alteration related to different physio-pathological conditions. Our data showed critical conditions for serum protein profiles depending on storage times and temperatures: 23 degrees C, 4 degrees C, -20 degrees C and -80 degrees C. We demonstrated that upon a -20 degrees C short term storage, characteristic degradation profiles are associated with different clinical groups. Protein signals were further identified after preparative HPLC separation by peptide sequencing on a nanoLC-Q-TOF TANDEM mass spectrometer. Apolipoprotein A-IV and complement C3 protein fragments, transthyretin and the oxidized isoforms in different apolipoprotein species represent the major molecular features of such a degradation pattern.

Reversible parkinsonism induced by prolonged treatment with valproate

Abstract We describe two patients who developed levodopa-responsive parkinsonism without dementia at least 4 years after beginning chronic valproate (VPA) treatment for seizures. Parkinsonism disappeared in less than 3 months after VPA substitution with carbamazepine.

Functional and neurochemical interactions within the amygdala–medial prefrontal cortex circuit and their relevance to emotional processing

The amygdala–medial prefrontal cortex (mPFC) circuit plays a key role in emotional processing. GABA-ergic inhibition within the mPFC has been suggested to play a role in the shaping of amygdala activity. However, the functional and neurochemical interactions within the amygdala–mPFC circuits and their relevance to emotional processing remain unclear. To investigate this circuit, we obtained resting-state functional magnetic resonance imaging (rs-fMRI) and proton MR spectroscopy in 21 healthy subjects to assess the potential relationship between GABA levels within mPFC and the amygdala–mPFC functional connectivity. Trait anxiety was assessed using the State-Trait Anxiety Inventory (STAI-Y2). Partial correlations were used to measure the relationships among the functional connectivity outcomes, mPFC GABA levels and STAI-Y2 scores. Age, educational level and amount of the gray and white matters within 1H-MRS volume of interest were included as nuisance variables. The rs-fMRI signals of the amygdala and the vmPFC were significantly anti-correlated. This negative functional coupling between the two regions was inversely correlated with the GABA+/tCr level within the mPFC and the STAI-Y2 scores. We suggest a close relationship between mPFC GABA levels and functional interactions within the amygdala–vmPFC circuit, providing new insights in the physiology of emotion.

Modafinil and armodafinil improve attention and global mental status in Lewy bodies disorders: preliminary evidence

Parkinson’s disease with dementia (PDD) and dementia with Lewy bodies (DLB) share several disturbances of attention, including cognitive fluctuations (FC), which are known to correlate with worse dementia symptoms (Varanese et al., 2010). Although cholinesterase inhibitors may improve them to some degree, their effect is inconsistent in PDD/DLB. Modafinil (Minzenberg and Carter, 2008) and armodafinil (Lankford, 2008), the racemic form of modafinil, are wake-promoting eugeroic agents that activate the central nervous system through the hypocretin/orexin system. They have been shown to improve attention in different conditions (Minzenberg and Carter, 2008; Lankford, 2008). Improvement of sleepiness is reported for modafinil in PDD and recently for armodafinil in DLB patients, with related improvement of quality of life (Kuntz et al., 2012). There is currently no evidence, however, in respect to attention and global mental status.

Irrelevant Features of a Stimulus Can Either Facilitate or Disrupt Performance in a Working Memory Task: The Role of Fluid Intelligence

It has been shown that fluid intelligence (gf) is fundamental to overcome interference due to information of a previously encoded item along a task-relevant domain. However, the biasing effect of task-irrelevant dimensions is still unclear as well as its relation with gf. The present study aimed at clarifying these issues. Gf was assessed in 60 healthy subjects. In a different session, the same subjects performed two versions (letter-detection and spatial) of a three-back working memory task with a set of physically identical stimuli (letters) presented at different locations on the screen. In the letter-detection task, volunteers were asked to match stimuli on the basis of their identity whereas, in the spatial task, they were required to match items on their locations. Cross-domain bias was manipulated by pseudorandomly inserting a match between the current and the three back items on the irrelevant domain. Our findings showed that a task-irrelevant feature of a salient stimulus can actually bias the ongoing performance. We revealed that, at trials in which the current and the three-back items matched on the irrelevant domain, group accuracy was lower (interference). On the other hand, at trials in which the two items matched on both the relevant and irrelevant domains, the group showed an enhancement of the performance (facilitation). Furthermore, we demonstrated that individual differences in fluid intelligence covaries with the ability to override cross-domain interference in that higher gf subjects showed better performance at interference trials than low gf subjects. Altogether, our findings suggest that stimulus features irrelevant to the task can affect cognitive performance along the relevant domain and that gf plays an important role in protecting relevant memory contents from the hampering effect of such a bias.

Enhanced release of acid sphingomyelinase-enriched exosomes generates a lipidomics signature in CSF of Multiple Sclerosis patients

Multiple Sclerosis (MuS) is a complex multifactorial neuropathology, resulting in heterogeneous clinical presentation. A very active MuS research field concerns the discovery of biomarkers helpful to make an early and definite diagnosis. The sphingomyelin pathway has emerged as a molecular mechanism involved in MuS, since high levels of ceramides in cerebrospinal fluid (CSF) were related to axonal damage and neuronal dysfunction. Ceramides are the hydrolysis products of sphingomyelins through a reaction catalyzed by a family of enzymes named sphingomyelinases, which were recently related to myelin repair in MuS. Here, using a lipidomic approach, we observed low levels of several sphingomyelins in CSF of MuS patients compared to other inflammatory and non-inflammatory, central or peripheral neurological diseases. Starting by this result, we investigated the sphingomyelinase activity in CSF, showing a significantly higher enzyme activity in MuS. In support of these results we found high number of total exosomes in CSF of MuS patients and a high number of acid sphingomyelinase-enriched exosomes correlated to enzymatic activity and to disease severity. These data are of diagnostic relevance and show, for the first time, high number of acid sphingomyelinase-enriched exosomes in MuS, opening a new window for therapeutic approaches/targets in the treatment of MuS.

Electrophysiological indices of interference resolution covary with individual fluid intelligence: investigating reactive control processes in a 3-back working memory task☆

It has been proposed that the well-established relationship between working memory (WM) and fluid intelligence (gf) is mediated by executive mechanisms underlying interference control. The latter relies upon the integrity of a frontoparietal brain network, whose activity is modulated by general cognition. In regards to the chronology of this activation, only few EEG studies investigated the topic, although none of them examined the regional interaction or the effects of individual differences in gf. The current investigation sought at extending previous research by characterizing the EEG markers (temporal activation and regional coupling) of interference control and the effects of the individual variation in gf. To this end, we recorded the EEG activity of 33 participants while performing verbal and spatial versions of a 3-back WM task. In a separate session, participants were administered with a test of fluid intelligence. Interference-inducing trials were associated with an increased negativity in the frontal scalp region occurring in two separate time windows and probably reflecting two different stages of the underlying cognitive process. In addition, we found that scalp distribution of such activity differed among individuals, being the strongest activation of the left and right frontolateral sites related to high gf level. Finally, high- and low-gf participants showed different patterns in the modulation of regional connectivity (electrodes coherence in the range of 4.5-7.5Hz) according to changes in attention load among types of trials. Our findings suggest that high-gf participants may rely upon effective engagement and modulation of attention resources to face interference.

Lewy Body Dementia

Dementia with Lewy bodies (DLB) represents the second most common cause of neurodegenerative dementia after Alzheimer’s disease (AD).

“Nail loss after teriflunomide treatment: A new potential adverse event”

Nail loss might represent a new, reversible, adverse event associated with teriflunomide treatment. It shares close analogies with hair loss and thinning, known adverse events of teriflunomide. MS specialists should be aware of this possibility and evaluate treatment discontinuation.