Identification of novel fluorescent probes preventing PrPSc replication in prion diseases

Prion diseases are serious, not curable neurodegenerative disorders caused by the accumulation of the misfolded protein PrPScthat represents the pathological variant of the normally folded cellular protein PrPC. Molecules that bind the cellular isoform PrPCpreventing its misfolding, could arrest the progression of pathological conditions related to the abnormal PrP protein. In this context, by combining 3D-QSAR model, derived from pharmacophore-based alignment, with molecular docking procedures and physico-chemical properties prediction we have developed a virtual screening protocol to find novel chemicals able to prevent PrPCmisfolding. We identified different hits characterized by low toxicity and able to inhibit PrPScaccumulation in\uc2\ua0vitro in prion-infected neuroblastoma cell lines (ScN2a). In this assay, the pyrroloquinoxaline hydrazone 96 showed the higest potency with an IC50value of 1.6\uc2\ua0\uce\ubcM. Pyrroloquinoxaline 96 was demonstrated also to bind PrPScaggregates in infected ScN2a cells with a fluorescence pattern comparable to that found for Thioflavin-T. In consideration of its satisfactory physico-chemical properties, including predicted blood brain barrier permeability, 96 could represent an interesting prototypic hit for the development of diagnostic and therapeutic probes for prion diseases

Laser-Induced Graphene as Electrode Material in Proton-Exchange Membrane Fuel Cells

The preparation of graphene foams via laser pyrolysis of polyimides has gained success due to its ease and speed of processing. Established applications of laser-induced graphene (LIG) involve micro-supercapacitors, batteries, sensors, and water treatment. However, to the best of our knowledge, only a few studies have focused on potential applications of LIG in proton-exchange membrane fuel cells (PEM-FCs). In this study, we demonstrate that LIG obtained from SPEEK films (LIG-S) presents all the key features required of a PEM-FC electrode. Moreover, electrochemical tests in rotating disk and half-cell setups highlight the intrinsic catalytic activity of LIG towards the oxygen reduction reaction. This activity is attributed to structural defects in the LIG lattice and sulfur doping incorporated from the SPEEK precursor, and it may lower the catalyst loading required to reach competitive cell performance

Age, gender and drug therapy influences on Tpeak-tend interval and on electrical risk score

Background and objectives: Electrical risk score (ERS) has been proposed as easy, inexpensive test to stratify of sudden cardiac death (SCD) risk in subjects with normal left ventricular function. Potentially, aging, gender and drugs can influence ERS affecting two on six electrical markers, particularly, those based on the repolarization. Aim of this study was to establish aging, gender and drug therapy possible influences on ERS and mortality in elderly patients. Method: 237 consecutive, low SCD risk-outpatients with asymptomatic and treated cardiovascular risk factors were analyzed. Six simple ECG markers composed ERS: heart rate (N75 bpm); left ventricular hypertrophy (Sokolow-Lyon criteria); delayed QRS transition zone (≥V4), frontal QRS-T angle (N90°), long QTBazett; long T peak to T end interval (Tp-e). We obtained ERS in 237 outpatients, grouped according age (b40 ys, ≥40 to b60 ys and ≥60 ys), gender and drug therapy with or without possible influence on the repolarization phase. Results: Two-hundred-thirty-seven patients were grouped respectively in the following age classes: b40 years old; ≥40 to b60 years old and ≥60 years old. ERS (p b 0.05), QTBazett (p b 0.001), Tp-e (p b 0.001) were higher in older subjects independently from gender, drug therapy and cardiovascular comorbidity. After two years we reported a 7.3% of mortality in the older groups; age (deceased versus survivors: 80 ± 4 versus 73 ± 7 years, p b 0.05) and Tp-e (deceased versus survivors: 117 ± 15 versus 93 ± 21 ms, p b 0.05) were significantly lower in survivors,multivariable logistic regression analysis selected only the Tp-e as significant risk factor for totalmortality (odd ratio 1.06, 95% CI: 1.01–1.12, p b 0.05). Conclusion: Aging was associated to the ERS and repolarization phase derangement. Tp-e should be considered a marker of total mortality rather than SCD in the over sixty years old patients

Time- and frequency-domain analysis of repolarization phase during recovery from exercise in healthy subjects

Background/aim: Recently, data from temporal dispersion of myocardial repolarization analysis have gained a capital role in the sudden cardiac death risk stratification. Aim of this study was to evaluate the influence of heart rate, autonomic nervous system and controlled breathing on different myocardial repolarization markers in healthy subjects. Method: Myocardial repolarization dispersion markers from short period (5-minutes) ECG analysis (time and frequency domain) have been obtained in 21 healthy volunteers during these conditions: free breathing (rest); controlled breathing (resp); the first 5-minutes of post-exercise recovery phases (exercisePeak); maximum sympathetic activation, and during the second five minutes of post-exercise recovery phases (exerciseRecovery), intermediate sympathetic activation. Finally, we analyzed the whole repolarization (QTe), the QT peak (QTp) and T peak - T end intervals (Te). Results: During the exercisePeak major part of repolarization variables changed in comparison to the rest and resp conditions. Particularly, QTe, QTp, Te standard deviations (QTeSD, QTpSD, TeSD), variability indexes (QTeVI, QTpVI), normalized variances (QTeVN, QTpVN, TeVN), the ratio between short term QTe, QTp, Te variability RR (STVQTe/RR, STVQTp/RR and STVTe/RR increased. During exerciserecovery QTpSD (p<0.05), QTpVI (p<0.05), QTeVN (p<0.05), QTpVN (p<0.001), TeVN (p<0.05), STVQTe/RR (p<0.05), STVQTp/RR (p<0.001) and STVTe/RR (p<0.001) were significantly higher in comparison with the rest. The slope between QTe (0.24±0.06) or QTp (0.17±0.06) and RR were significantly higher than Te (0.07±0.06, p<0.001). Conclusion: Heart rate and sympathetic activity, obtained during exercise, seem able to influence the time domain markers of myocardial repolarization dispersion in healthy subjects whereas they do not alter any spectral components

Short-period temporal repolarization dispersion in subjects with atrial fibrillation and decompensated heart failure

Background/objectives: The association between chronic heart failure (CHF) and permanent atrial fibrillation is very frequent. The repolarization duration was already found predictive for atrial fibrillation. Aim of this study was to evaluate the influence of atrial fibrillation on short period repolarization variables in decompensated CHF patients. Method: We used 5 minutes ECG recordings to assess the mean, standard deviation (SD) and normalized variance (NV) of the following variables: QT end (QTe), QT peak (QTp) and T peak to T end (Te) in 121 decompensated CHF, of whom 40 had permanent atrial fibrillation, too. We reported also the 30-day mortality. Results: QTpSD (p<0.01), TeSD (p<0.01), QTpVN (p<0.01) and TeVN (p<0.01) were higher in the atrial fibrillation than among sinus rhythm CHF subjects. Multivariable logistic analysis selected only TeSD (odd ratio, o.r.: 1.32, 95% confidence interval, c.i.: 1.06-1.65, p: 0.015) associated with atrial fibrillation. A total of 27 patients died during the 30-days follow-up (overall mortality rate 22%), 7 (18%) and 20 (25%) respectively in the atrial fibrillation and sinus rhythm patients. Furthermore, the following variables were associated to the morality risk: NT-pro Brain Natriuretic Peptide (o.r.: 1.00, 95% c.i.: 1.00-1.00, p:0.041), left ventricular end diastolic diameter (o.r.: 0.81, 95% c.i.: 0.67-0.96, p: 0.010) and Te mean (o.r.: 1.04, 95% c.i.: 1.02-1.09, p:0.012). Conclusion: In decompensated CHF subjects, Te mean seems be associated to mortality and TeSD to the permanent atrial fibrillation. We could hypothesize that, during severe CHF, the multi-level ionic CHF channel derangement could be critical in influencing these non-invasive markers. (ClinicalTrials.gov number, NCT04127162) This article is protected by copyright. All rights reserved. Keywords: Chronic heart failure; QT; QTVI; Tpeak-Tend; mortality; permanent atrial fibrillation; temporal dispersion of repolarization phase

Time‐ and frequency‐domain analysis of repolarization phase during recovery from exercise in healthy subjects

Background/aim: Recently, data from temporal dispersion of myocardial repolarization analysis have gained a capital role in the sudden cardiac death risk stratification. Aim of this study was to evaluate the influence of heart rate, autonomic nervous system and controlled breathing on different myocardial repolarization markers in healthy subjects. Method: Myocardial repolarization dispersion markers from short period (5-minutes) ECG analysis (time and frequency domain) have been obtained in 21 healthy volunteers during these conditions: free breathing (rest); controlled breathing (resp); the first 5-minutes of post-exercise recovery phases (exercisePeak); maximum sympathetic activation, and during the second five minutes of post-exercise recovery phases (exerciseRecovery), intermediate sympathetic activation. Finally, we analyzed the whole repolarization (QTe), the QT peak (QTp) and T peak - T end intervals (Te). Results: During the exercisePeak major part of repolarization variables changed in comparison to the rest and resp conditions. Particularly, QTe, QTp, Te standard deviations (QTeSD, QTpSD, TeSD), variability indexes (QTeVI, QTpVI), normalized variances (QTeVN, QTpVN, TeVN), the ratio between short term QTe, QTp, Te variability RR (STVQTe/RR, STVQTp/RR and STVTe/RR increased. During exerciserecovery QTpSD (p<0.05), QTpVI (p<0.05), QTeVN (p<0.05), QTpVN (p<0.001), TeVN (p<0.05), STVQTe/RR (p<0.05), STVQTp/RR (p<0.001) and STVTe/RR (p<0.001) were significantly higher in comparison with the rest. The slope between QTe (0.24±0.06) or QTp (0.17±0.06) and RR were significantly higher than Te (0.07±0.06, p<0.001). Conclusion: Heart rate and sympathetic activity, obtained during exercise, seem able to influence the time domain markers of myocardial repolarization dispersion in healthy subjects whereas they do not alter any spectral components

Short-period temporal dispersion repolarization markers predict 30-days mortality in decompensated heart failure

Background and Objectives: Electrocardiographic (ECG) markers of the temporal dispersion of the myocardial repolarization phase have been shown able to identify chronic heart failure (CHF) patients at high mortality risk. The present prospective single-center study sought to investigate in a well-characterized cohort of decompensated heart failure (HF) patients the ability of short-term myocardial temporal dispersion ECG variables in predicting the 30-day mortality, as well as their relationship with N-terminal Pro Brain Natriuretic Peptide (NT-proBNP) plasmatic values. Method:One hundred and thirteen subjects (male: 59, 67.8%) with decompensated CHF underwent 5 min of ECG recording, via a mobile phone. We obtained QT end (QTe), QT peak (QTp) and T peak to T end (Te) and calculated the mean, standard deviation (SD), and normalized index (VN). Results: Death occurred for 27 subjects (24%) within 30 days after admission. Most of the repolarization indexes (QTe mean (p < 0.05), QTeSD (p < 0.01), QTpSD (p < 0.05), mean Te (p < 0.05), TeSD (p < 0.001) QTeVN (p < 0.05) and TeVN (p < 0.01)) were significantly higher in those CHF patients with the highest NT proBNP (>75th percentile). In all the ECG data, only TeSD was significantly and positively related to the NT-proBNP levels (r: 0.471; p < 0.001). In the receiver operating characteristic (ROC)analysis, the highest accuracy for 30-day mortality was found for QTeSD (area under curve, AUC: 0.705, p < 0.01) and mean Te (AUC: 0.680, p < 0.01), whereas for the NT-proBNP values higher thanthe 75th percentile, the highest accuracy was found for TeSD (AUC: 0.736, p < 0.001) and QTeSD (AUC: 0.696, p < 0.01). Conclusion: Both mean Te and TeSD could be considered as reliable markers of worsening HF and of 30-day mortality. Although larger and possibly interventional studies are needed to confirm our preliminary finding, these non-invasive and transmissible ECG parameters could be helpful in the remote monitoring of advanced HF patients and, possibly, in their clinical management. (ClinicalTrials.gov number, NCT04127162)

Hospital mortality in decompensated heart failure. a pilot study

Background/aim Heart failure is a leading cause of morbidity and mortality worldwide and it is a major cause of emergency department access for cardiovascular disease patients. Aim of this study was to identify the electrocardiographic (ECG) markers, based on short-term temporal repolarization dispersion, capable to individuate decompensated chronic heart failure (CHF) patients at high mortality risk. Methods We obtained the following variables from an ECG recording, monitored via mobile phone, during 5-minute recordings in decompensated CHF patients: RR, QT end (QTe), QT peak (QTp) and T peak to T end (Te) and we calculated mean, standard deviation (SD) and normalized index (N). Results In-hospital mortality occurred for 25 subjects on 101 studied (25%). Deceased patients showed higher QTeSD (p < 0.01), Te mean (p < 0.01), TeSD (p < 0.05), QTeVN (p < 0.05) than the surviving group. Logistic multivariable analysis evidenced that Te mean was a significant predictor of in-hospital mortality (odd ratio: 0.09, 95% confidence limit: 0.02–0.35, p: 0.001). At multiple regression analysis, TeSD was significantly and positively related only to the NT-pro BNP levels (r: 0.540; p < 0.001). The Te mean (AUC: 0.677 p < 0.01) and TeSD (AUC: 0.647, p: 0.05) showed significant sensitivity/specificity for the event. Conclusions The Te mean and TeSD seem to be a promising noninvasive clinical marker able to identify patients with decompensated CHF at high risk of in-hospital mortality

GM1 oligosaccharide efficacy against α-synuclein aggregation and toxicity in vitro

Fibrillary aggregated α-synuclein represents the neurologic hallmark of Parkinson's disease and is considered to play a causative role in the disease. Although the causes leading to α-synuclein aggregation are not clear, the GM1 ganglioside interaction is recognized to prevent this process. How GM1 exerts these functions is not completely clear, although a primary role of its soluble oligosaccharide (GM1-OS) is emerging. Indeed, we recently identified GM1-OS as the bioactive moiety responsible for GM1 neurotrophic and neuroprotective properties, specifically reverting the parkinsonian phenotype both in in vitro and in vivo models. Here, we report on GM1-OS efficacy against the α-synuclein aggregation and toxicity in vitro. By amyloid seeding aggregation assay and NMR spectroscopy, we demonstrated that GM1-OS was able to prevent both the spontaneous and the prion-like α-synuclein aggregation. Additionally, circular dichroism spectroscopy of recombinant monomeric α-synuclein showed that GM1-OS did not induce any change in α-synuclein secondary structure. Importantly, GM1-OS significantly increased neuronal survival and preserved neurite networks of dopaminergic neurons affected by α-synuclein oligomers, together with a reduction of microglia activation. These data further demonstrate that the ganglioside GM1 acts through its oligosaccharide also in preventing the α-synuclein pathogenic aggregation in Parkinson's disease, opening a perspective window for GM1-OS as drug candidate