Developmental Effects of Chronic Low-Level Arsenic Exposure in Mouse Embryonic Stem Cells and in Human Induced Pluripotent Stem Cells

Arsenic is an environmental contaminant commonly found in food and drinking water. Exposure to arsenic during embryonic development has been linked to reduced muscle growth, disrupted muscle development and locomotor activity, impaired neurodevelopment, reduced IQ, impaired memory and learning deficits. While the mechanisms responsible for developmental changes following in utero exposure to arsenic are not well known, one possibility is that arsenic might disrupt proper cellular differentiation. Therefore, we aimed to investigate the mechanisms by which arsenic exposure could alter stem cell differentiation into neurons. First, we continuously exposed P19 mouse embryonic stem (ES) cells to 0.1 μM (7.5 ppb) arsenic for 28 weeks to assess if chronic, low level arsenic exposure would delay cellular differentiation into neuronal cells. Importantly, this concentration is below the current drinking water standard of 10 ppb. The results show temporal changes of genes associated with pluripotency and cellular differentiation. Specifically, starting at week 12, transcript levels of the pluripotency markers Sox2 and Oct4 were increased by 1.9- to 2.5- fold in arsenic-exposed cells. By week 16, SOX2 protein expression was increased, and starting at week 20, the expression of a SOX2 target protein, N-cadherin, was also increased. Concurrently, by week 16, levels of the differentiation marker Gdf3 were decreased by 3.4- fold, along with the reduced phosphorylation of the GDF3 target protein SMAD2/3. To investigate the mechanisms responsible for maintaining pluripotency and hindering cellular differentiation into neurons, RNA sequencing was performed in control and arsenic-exposed cells at week 8, 16 and 24. This analysis revealed significant exposure-dependent changes in gene expression starting at week 16. Pathway analysis showed that arsenic exposure disrupts the Hippo signaling pathway, which is involved in pluripotency maintenance and embryonic development. Immunohistochemistry revealed that the ratios between nuclear (active) and cytoplasmic (inactive) expression of the main effector YAP and the main transcription factor TEAD were significantly increased in arsenic-exposed cells at week 16 and 28. Consistently, expression of the Hippo pathway target genes Ctgf and c-Myc were also significantly upregulated following arsenic exposure. These results indicate that chronic arsenic exposure impairs the Hippo signaling pathway resulting in increased YAP activation, thereby reducing neuronal differentiation. Previous studies have shown that P19 cells differentiate into sensory neurons, so we also wanted to investigate whether arsenic impaired differentiation into motor neurons. Thus, we switched to using human induced pluripotent stem (iPS) cells, which can differentiate into day 6 neuroepithelial progenitors (NEPs), day 12 motor neuron progenitors (MNPs), day 18 early motor neurons (MNs) and day 28 mature MNs. During this process, cells were exposed to arsenic concentrations up to 0.75 μM (56.25 ppb), and morphological alterations along with pluripotency and stage-specific neuronal markers were assessed. Day 6 NEPs exposed to arsenic had reduced levels of the neural progenitor/stem cell marker NES and neuroepithelial progenitor marker SOX1, while levels of these transcripts were increased in MNPs at day 12. Additionally, levels of the motor neuron progenitor marker OLIG2 were increased in day 12 MNPs while levels of the cholinergic neuron marker CHAT were reduced by 2.5- fold in MNPs exposed arsenic. RNA sequencing and pathway analysis showed that the cholinergic synapse pathway was impaired following exposure to 0.5 μM arsenic, and that transcript levels of genes involved in acetylcholine synthesis (CHAT), transport (SLC18A3 and SLC5A7) and degradation (ACHE) were all downregulated in early motor neurons at day 18. In mature motor neurons at day 28, expression of MAP2 and ChAT protein was significantly downregulated by 2.8- and 2.1- fold, respectively, concomitantly with a reduction in neurite length by 1.8- fold following exposure to 0.5 μM arsenic. Similarly, adult mice exposed to 100 ppb arsenic for five weeks had significantly reduced hippocampal ChAT levels. Taken all together, the results of the dissertation show that environmentally relevant levels of arsenic have detrimental effects on neuronal differentiation

Supramolecular Semiconductivity through Emerging Ionic Gates in Ion–Nanoparticle Superlattices

The self-assembly of nanoparticles driven by small molecules or ions may produce colloidal superlattices with features and properties reminiscent of those of metals or semiconductors. However, to what extent the properties of such supramolecular crystals actually resemble those of atomic materials often remains unclear. Here, we present coarse-grained molecular simulations explicitly demonstrating how a behavior evocative of that of semiconductors may emerge in a colloidal superlattice. As a case study, we focus on gold nanoparticles bearing positively charged groups that self-assemble into FCC crystals via mediation by citrate counterions. In silico ohmic experiments show how the dynamically diverse behavior of the ions in different superlattice domains allows the opening of conductive ionic gates above certain levels of applied electric fields. The observed binary conductive/nonconductive behavior is reminiscent of that of conventional semiconductors, while, at a supramolecular level, crossing the "band gap " requires a sufficient electrostatic stimulus to break the intermolecular interactions and make ions diffuse throughout the superlattice's cavities

Hereditary angioedema: Assessing the hypothesis for underlying autonomic dysfunction

Background Attacks of Hereditary Angioedema due to C1-inhibitor deficiency (Cl-INH-HAE) are often triggered by stressful events/hormonal changes. Objective Our study evaluates the relationship between autonomic nervous system (ANS) and contact/complement system activation. Methods Twenty-three HAE patients (6 males, mean age 47.5 +/- 11.4 years) during remission and 24 healthy controls (8 males, mean age 45.3 +/- 10.6 years) were studied. ECG, beat-by-beat blood pressure, respiratory activity were continuously recorded during rest (10') and 75degrees- head-up tilt (10'). C1-INH, C4, cleaved high molecular weight kininogen (cHK) were assessed; in 16 patients and 11 controls plasma catecholamines were also evaluated. Spectral analysis of heart rate variability allowed extraction of low-(LF) and high-(HF)frequency components, markers of sympathetic and vagal modulation respectively. Results HAE patients showed higher mean systolic arterial pressure (SAP) than controls during both rest and tilt. Tilt induced a significant increase in SAP and its variability only in controls. Although sympathetic modulation (LFnu) increased significantly with tilt in both groups, LF/HF ratio, index of sympathovagal balance, increased significantly only in controls. At rest HAE patients showed higher noradrenaline values (301.4 +/- 132.9 pg/ml vs 210.5 +/- 89.6 pg/ml, p = 0.05). Moreover, in patients tilt was associated with a significant increase in cHK, marker of contact system activation (49.5 +/- 7.5% after T vs 47.1 +/- 7.8% at R, p = 0.01). Conclusions Our data are consistent with altered ANS modulation in HAE patients, i.e. increased sympathetic activation at rest and blunted response to orthostatic challenge. Tilt test-induced increased HK cleavage suggests a link between stress and bradykinin production

Towards a map of the Upper Pleistocene loess of the Po Plain Loess Basin (Northern Italy)

Upper Pleistocene (MIS 4-2) loess sequences occur in most of continental Europe and in Northern Italy along the Po Plain Loess Basin. Loess is distributed along the flanks of the Po Plain and was deposited on glacial deposits, fluvial terraces, uplifted isolated hills, karst plateaus, slopes and basins of secondary valleys. Loess bodies are generally tiny and affected by pedogenesis, being locally slightly reworked by slope processes and bioturbation. Notwithstanding, loess in the Po Plain is an important archive of paleoenviron-mental record and its mapping provides new insights in paleoenvironmental and palaeoseismic reconstructions of Northern Ital

Effectiveness of cardiac resynchronization therapy in heart failure patients with valvular heart disease: comparison with patients affected by ischaemic heart disease or dilated cardiomyopathy. The InSync/InSync ICD Italian Registry

AimsTo analyse the effectiveness of cardiac resynchronization therapy (CRT) in patients with valvular heart disease (a subset not specifically investigated in randomized controlled trials) in comparison with ischaemic heart disease or dilated cardiomyopathy patients.Methods and resultsPatients enrolled in a national registry were evaluated during a median follow-up of 16 months after CRT implant. Patients with valvular heart disease treated with CRT (n = 108) in comparison with ischaemic heart disease (n = 737) and dilated cardiomyopathy (n = 635) patients presented: (i) a higher prevalence of chronic atrial fibrillation, with atrioventricular node ablation performed in around half of the cases; (ii) a similar clinical and echocardiographic profile at baseline; (iii) a similar improvement of LVEF and a similar reduction in ventricular volumes at 6-12 months; (iv) a favourable clinical response at 12 months with an improvement of the clinical composite score similar to that occurring in patients with dilated cardiomyopathy and more pronounced than that observed in patients with ischaemic heart disease; (v) a long-term outcome, in term of freedom from death or heart transplantation, similar to patients affected by ischaemic heart disease and basically more severe than that of patients affected by dilated cardiomyopathy.ConclusionIn 'real world' clinical practice, CRT appears to be effective also in patients with valvular heart disease. However, in this group of patients the outcome after CRT does not precisely overlap any of the two other groups of patients, for which much more data are currently available

Adherence to antibiotic treatment guidelines and outcomes in the hospitalized elderly with different types of pneumonia

Background: Few studies evaluated the clinical outcomes of Community Acquired Pneumonia (CAP), Hospital-Acquired Pneumonia (HAP) and Health Care-Associated Pneumonia (HCAP) in relation to the adherence of antibiotic treatment to the guidelines of the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) in hospitalized elderly people (65 years or older). Methods: Data were obtained from REPOSI, a prospective registry held in 87 Italian internal medicine and geriatric wards. Patients with a diagnosis of pneumonia (ICD-9 480-487) or prescribed with an antibiotic for pneumonia as indication were selected. The empirical antibiotic regimen was defined to be adherent to guidelines if concordant with the treatment regimens recommended by IDSA/ATS for CAP, HAP, and HCAP. Outcomes were assessed by logistic regression models. Results: A diagnosis of pneumonia was made in 317 patients. Only 38.8% of them received an empirical antibiotic regimen that was adherent to guidelines. However, no significant association was found between adherence to guidelines and outcomes. Having HAP, older age, and higher CIRS severity index were the main factors associated with in-hospital mortality. Conclusions: The adherence to antibiotic treatment guidelines was poor, particularly for HAP and HCAP, suggesting the need for more adherence to the optimal management of antibiotics in the elderly with pneumonia

Black holes, gravitational waves and fundamental physics: a roadmap

The grand challenges of contemporary fundamental physics—dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem—all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions. The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature. The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress. This write-up is an initiative taken within the framework of the European Action on 'Black holes, Gravitational waves and Fundamental Physics'