A conducting polymer with enhanced electronic stability applied in cardiac models

Electrically active constructs can have a beneficial effect on electroresponsive tissues, such as the brain, heart, and nervous system. Conducting polymers (CPs) are being considered as components of these constructs because of their intrinsic electroactive and flexible nature. However, their clinical application has been largely hampered by their short operational time due to a decrease in their electronic properties. We show that, by immobilizing the dopant in the conductive scaffold, we can prevent its electric deterioration. We grew polyaniline (PANI) doped with phytic acid on the surface of a chitosan film. The strong chelation between phytic acid and chitosan led to a conductive patch with retained electroactivity, low surface resistivity (35.85 ± 9.40 kilohms per square), and oxidized form after 2 weeks of incubation in physiological medium. Ex vivo experiments revealed that the conductive nature of the patch has an immediate effect on the electrophysiology of the heart. Preliminary in vivo experiments showed that the conductive patch does not induce proarrhythmogenic activities in the heart. Our findings set the foundation for the design of electronically stable CP-based scaffolds. This provides a robust conductive system that could be used at the interface with electroresponsive tissue to better understand the interaction and effect of these materials on the electrophysiology of these tissues

WHEN AUTISM IS FEMALE: AN INVESTIGATION INTO GENDER BIASES IN THE CLINICAL ASSESSMENT OF AUTISM SPECTRUM DISORDER

In recent decades, autism spectrum disorder (ASD) has sparked growing interest within the scientific community, not only due to its clinical complexity, but also because of the social, educational, and diagnostic implications it entails. At the same time, the rise in diagnoses has led to greater collective awareness, while also highlighting a series of unresolved issues, particularly regarding gender differences in how the disorder presents. Numerous studies emphasize that ASD may appear more subtly in girls and women, often masked by social adaptation strategies - known as “camouflaging” - which make timely and accurate diagnosis more challenging. Moreover, the self-reported diagnostic experiences of many women - and the frequent lack of recognition or delayed identification of their condition - has raised the following research question: are there potential gender biases in diagnostic processes, such that cultural and social expectations toward women, often seen as more empathetic or socially competent, might lead clinicians to underestimate or misinterpret ASD symptoms in females? The aim of this research - born from a collaboration between the Departments of Neuroscience and Neuropsychology and Special Education at the University of Verona - is to explore the role of potential gender biases in autism diagnosis. This is achieved through an experimental survey conducted with a sample of professionals in the clinical and psychoeducational fields: around one hundred practitioners responded to the survey, all of whom are involved in making diagnostic assessments within public or affiliated private healthcare services. Using a methodology based on diagnostic vignettes, the research seeks to understand whether - and how - the gender of the subject described in the vignettes influences the recognition of the disorder. The items were selected so that the presence of ASD was equally distributed between male and female subjects. The diagnostic responses from professionals showed a result of approximately 68% male and 32% female identifications, confirming the presence of diagnostic biases. This initial finding prompts further reflection: how can we improve the quality and fairness of diagnoses by fostering greater awareness of the implicit factors that may interfere with evaluative processes

A quantitative study on the growth variability of tumour cell clones in vitro

Objectives: In this study, we quantify the growth variability of tumour cell clones from a human leukemia cell line. Materials and methods: We have used microplate spectrophotometry to measure the growth kinetics of hundreds of individual cell clones from the Molt3 cell line. The growth rate of each clonal population has been estimated by fitting experimental data with the logistic equation. Results: The growth rates were observed to vary among different clones. Up to six clones with a growth rate above or below the mean growth rate of the parent population were further cloned and the growth rates of their offsprings were measured. The distribution of the growth rates of the subclones did not significantly differ from that of the parent population thus suggesting that growth variability has an epigenetic origin. To explain the observed distributions of clonal growth rates we have developed a probabilistic model assuming that the fluctuations in the number of mitochondria through successive cell cycles are the leading cause of growth variability. For fitting purposes, we have estimated experimentally by flow cytometry the maximum average number of mitochondria in Molt3 cells. The model fits nicely the observed distributions of growth rates, however, cells in which the mitochondria were rendered non functional (rho-0 cells) showed only a 30% reduction in the clonal growth variability with respect to normal cells. Conclusions: A tumor cell population is a dynamic ensemble of clones with highly variable growth rate. At least part of this variability is due to fluctuations in the number of mitochondria.Comment: 31 pages, 5 figure

The relationship between liver histology and thyroid function tests in patients with nonalcoholic fatty liver disease (NAFLD)

Background Data on the role of hypothyroidism in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and liver fibrosis are conflicting, although selective Thyroid Hormone Receptor (THR)-β agonists have been identified as potential therapy in patients with non-alcoholic steatohepatitis (NASH). Therefore, we investigated the association between hypothyroidism and NAFLD histological features potentially associated with progressive liver disease. Methods Between 2014 and 2016, consecutive patients with histologically proven NAFLD and frozen serum available for thyroid function tests assessment were included. NAFLD was staged according to the NAFLD Activity Score (NAS), and fibrosis according to Kleiner. NASH was defined as NAS 4, significant fibrosis as F2-F4 and significant steatosis as S2-S3. Thyroid function tests (TFT; TSH, FT3, FT4, rT3), TPO-Ab and Tg-Ab were also assessed. Results Fifty-two patients were analyzed: Median age 54 years, 58% females, LSM 7.8 kPa, 27% diabetics, 14% hypothyroid. At histology, NASH was present in 21 (40%), F2-F4 in 28 (54%) and S2-S3 in 30 (58%) patients. Rates of hypothyroidism were similar independently of the presence of NASH (p = 0.11), significant fibrosis (p = 0.21) or steatosis (p = 0.75). However, hypothyroid patients displayed a higher NAS (p = 0.02) and NASH (p = 0.06) prevalence. At multivariate analysis, TFT were not independently associated with histology. Conclusion Hypothyroidism was highly prevalent in NAFLD patients, and was associated with increased NAFLD activity, but not with fibrosis and steatosis severity. Thus, thyroid dysfunction might play a direct and/or indirect in the pathogenesis of NAFLD and NASH

Reference values for exaled nitric oxide (reveno) study.

BACKGROUND:Despite the widespread use of fractional exhaled nitric oxide (FENO) as a biomarker of airways inflammation, there are no published papers describing normal FENO values in a large group of healthy adults.OBJECTIVE:The aim of this study was to establish adult FENO reference values according to the international guidelines.METHODS:FENO was measured in 204 healthy, non-smoking adults with normal spirometry values using the on-line single-breath technique, and the results were analysed chemiluminescently.RESULTS:The main result of the study was the significant difference in FENO values between men and women, thus indicating that gender-based reference FENO values are necessary. The FENO levels obtained at expiratory flows of 50 ml/s ranged from 2.6 to 28.8 ppb in men, and from 1.6 to 21.5 ppb in women.CONCLUSION:We propose reference FENO values for healthy adult men and women that could be used for clinical and research purposes

Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) for three dimensional visualization of myocardial tissue

AbstractSeveral pathologic conditions of the heart lead to cardiac structural remodelling. Given the high density and the opaque nature of the myocardium, deep three dimensional (3D) imaging is difficult to achieve and structural analysis of pathological myocardial structure is often limited to two dimensional images and of thin myocardial sections. Efficient methods to obtain optical clearing of the tissue for 3D visualisation are therefore needed. Here we describe a rapid, simple and versatile Free-of-Acrylamide SDS-based Tissue Clearing (FASTClear) protocol specifically designed for cardiac tissue. With this method 3D information regarding collagen content, collagen localization and distribution could be easily obtained across a whole 300 µm-thick myocardial slice. FASTClear does not induce structural or microstructural distortion and it can be combined with immunostaining to identify the micro- and macrovascular networks. In summary, we have obtained decolorized myocardial tissue suitable for high resolution 3D imaging, with implications for the study of complex cardiac tissue structure and its changes during pathology.</jats:p

Preconditioning of Cardiosphere-Derived Cells With Hypoxia or Prolyl-4-Hydroxylase Inhibitors Increases Stemness and Decreases Reliance on Oxidative Metabolism

Cardiosphere-derived cells (CDCs), which can be isolated from heart explants, are a promising candidate cell source for infarcted myocardium regeneration. However, current protocols used to expand CDCs require at least 1 month in vitro to obtain sufficient cells for transplantation. We report that CDC culture can be optimized by preconditioning the cells under hypoxia (2% oxygen), which may reflect the physiological oxygen level of the stem cell niche. Under hypoxia, the CDC proliferation rate increased by 1.4-fold, generating 6 × 10(6) CDCs with higher expression of cardiac stem cell and pluripotency gene markers compared to normoxia. Furthermore, telomerase (TERT), cytokines/ligands involved in stem cell trafficking (SDF/CXCR-4), erythropoiesis (EPO), and angiogenesis (VEGF) were increased under hypoxia. Hypoxic preconditioning was mimicked by treatment with two types of hypoxia-inducible factor (HIF) prolyl-4-hydroxylase inhibitors (PHDIs): dimethyloxaloylglycine (DMOG) and 2-(1-chloro-4-hydroxyisoquinoline-3-carboxamido) acetic acid (BIC). Despite the difference in specificity, both PHDIs significantly increased c-Kit expression and activated HIF, EPO, and CXCR-4. Furthermore, treatment with PHDIs for 24 h increased cell proliferation. Notably, all hypoxic and PHDI-preconditioned CDCs had decreased oxygen consumption and increased glycolytic metabolism. In conclusion, cells cultured under hypoxia could have potentially enhanced therapeutic potential, which can be mimicked, in part, by PHDIs

Physiological Biomimetic Culture System for Pig and Human Heart Slices

RATIONALE: Preclinical testing of cardiotoxicity and efficacy of novel heart failure therapies faces a major limitation: the lack of an in situ culture system that emulates the complexity of human heart tissue and maintains viability and functionality for a prolonged time. OBJECTIVE: To develop a reliable, easily reproducible, medium-throughput method to culture pig and human heart slices under physiological conditions for a prolonged period of time. METHODS AND RESULTS: Here, we describe a novel, medium-throughput biomimetic culture system that maintains viability and functionality of human and pig heart slices (300 µm thickness) for 6 days in culture. We optimized the medium and culture conditions with continuous electrical stimulation at 1.2 Hz and oxygenation of the medium. Functional viability of these slices over 6 days was confirmed by assessing their calcium homeostasis, twitch force generation, and response to β-adrenergic stimulation. Temporal transcriptome analysis using RNAseq at day 2, 6, and 10 in culture confirmed overall maintenance of normal gene expression for up to 6 days, while over 500 transcripts were differentially regulated after 10 days. Electron microscopy demonstrated intact mitochondria and Z-disc ultra-structures after 6 days in culture under our optimized conditions. This biomimetic culture system was successful in keeping human heart slices completely viable and functionally and structurally intact for 6 days in culture. We also used this system to demonstrate the effects of a novel gene therapy approach in human heart slices. Furthermore, this culture system enabled the assessment of contraction and relaxation kinetics on isolated single myofibrils from heart slices after culture. CONCLUSIONS: We have developed and optimized a reliable medium-throughput culture system for pig and human heart slices as a platform for testing the efficacy of novel heart failure therapeutics and reliable testing of cardiotoxicity in a 3D heart model

Deregulated intracellular pathways define novel molecular targets for HBV-specific CD8 T cell reconstitution in chronic hepatitis B

Background &amp; Aims: In chronic HBV infection, elevated reactive oxygen species levels derived from dysfunctional mitochondria can cause increased protein oxidation and DNA damage in exhausted virus-specific CD8 T cells. The aim of this study was to understand how these defects are mechanistically interconnected to further elucidate T cell exhaustion pathogenesis and, doing so, to devise novel T cell-based therapies. Methods: DNA damage and repair mechanisms, including parylation, CD38 expression, and telomere length were studied in HBV- specific CD8 T cells from chronic HBV patients. Correction of intracellular signalling alterations and improvement of antiviral T cell functions by the NAD precursor nicotinamide mononucleotide and by CD38 inhibition was assessed. Results: Elevated DNA damage was associated with defective DNA repair processes, including NAD-dependent parylation, in HBV-specific CD8 cells of chronic HBV patients. NAD depletion was indicated by the overexpression of CD38, the major NAD consumer, and by the significant improvement of DNA repair mechanisms, and mitochondrial and proteostasis functions by NAD supplementation, which could also improve the HBV-specific antiviral CD8 T cell function. Conclusions: Our study delineates a model of CD8 T cell exhaustion whereby multiple interconnected intracellular defects, including telomere shortening, are causally related to NAD depletion suggesting similarities between T cell exhaustion and cell senescence. Correction of these deregulated intracellular functions by NAD supplementation can also restore antiviral CD8 T cell activity and thus represents a promising potential therapeutic strategy for chronic HBV infection