A multiscale hybrid model for pro-angiogenic calcium signals in a vascular endothelial cell

Cytosolic calcium machinery is one of the principal signaling mechanisms by which endothelial cells (ECs) respond to external stimuli during several biological processes, including vascular progression in both physiological and pathological conditions. Low concentrations of angiogenic factors (such as VEGF) activate in fact complex pathways involving, among others, second messengers arachidonic acid (AA) and nitric oxide (NO), which in turn control the activity of plasma membrane calcium channels. The subsequent increase in the intracellular level of the ion regulates fundamental biophysical properties of ECs (such as elasticity, intrinsic motility, and chemical strength), enhancing their migratory capacity. Previously, a number of continuous models have represented cytosolic calcium dynamics, while EC migration in angiogenesis has been separately approached with discrete, lattice-based techniques. These two components are here integrated and interfaced to provide a multiscale and hybrid Cellular Potts Model (CPM), where the phenomenology of a motile EC is realistically mediated by its calcium-dependent subcellular events. The model, based on a realistic 3-D cell morphology with a nuclear and a cytosolic region, is set with known biochemical and electrophysiological data. In particular, the resulting simulations are able to reproduce and describe the polarization process, typical of stimulated vascular cells, in various experimental conditions.Moreover, by analyzing the mutual interactions between multilevel biochemical and biomechanical aspects, our study investigates ways to inhibit cell migration: such strategies have in fact the potential to result in pharmacological interventions useful to disrupt malignant vascular progressio

Osteogenic differentiation modulates the cytokine, chemokine, and growth factor profile of ASCs and SHED

Great efforts have been made to improve bone regeneration techniques owing to a growing variety of sources of stem cells suitable for autologous transplants. Specifically, adipose-derived stem cells (ASCs) and stems cells from human exfoliated deciduous teeth (SHED) hold great potential for bone tissue engineering and cell therapy. After a preliminary characterization of the main biomolecules ASCs and SHED released in their conditioned media, cells were kept both in normal and osteo-inducing conditions. Conventional assays were performed to prove their osteogenic potential such as quantitative real-time polymerase chain reaction (qRT-PCR) (for RUNX-2, collagen type I, osteopontin and osteonectin), alkaline phosphatase activity, osteocalcin production, and von Kossa staining. Conditioned media were tested again after the osteogenic induction and compared to maintaining condition both at base line and after 14 days of culture. The osteogenic condition inhibited the release of all the biomolecules, with the exception, concerning SHED, of growth-regulated alpha protein precursor (GRO\u3b1), and, to a lesser extent, interleukin (IL)-8. In conclusion, our data support that undifferentiated ASCs and SHED may be preferable to committed ones for general cell therapy approaches, due to their higher paracrine activity. Osteoinduction significantly affects the cytokine, chemokine, and growth factor profile in a differential way, as SHED kept a more pronounced pro-angiogenic signature than ASCs

Alternative strategies to inhibit tumor vascularization

Endothelial cells present in tumors show different origin, phenotype, and genotype with respect to the normal counterpart. Various mechanisms of intra-tumor vasculogenesis sustain the complexity of tumor vasculature, which can be further modified by signals deriving from the tumor microenvironment. As a result, resistance to anti-VEGF therapy and activation of compensatory pathways remain a challenge in the treatment of cancer patients, revealing the need to explore alternative strategies to the classical anti-angiogenic drugs. In this review, we will describe some alternative strategies to inhibit tumor vascularization, including targeting of antigens and signaling pathways overexpressed by tumor endothelial cells, the development of endothelial vaccinations, and the use of extracellular vesicles. In addition, anti-angiogenic drugs with normalizing effects on tumor vessels will be discussed. Finally, we will present the concept of endothelial demesenchymalization as an alternative approach to restore normal endothelial cell phenotype

Isolation and characterization of buccal fat pad and dental pulp mscs from the same donor

Mesenchymal stem cells (MSCs) can be harvested from different sites in the oral cavity, representing a reservoir of cells useful for regenerative purposes. As direct comparisons between at least two types of MSCs deriving from the same patient are surprisingly rare in scientific literature, we isolated and investigated the osteoinductive potential of dental pulp stem cells (DPSCs) and buccal fat pad stem cells (BFPSCs). MSCs were isolated from the third molar dental pulp and buccal fat pads of 12 patients. The number of viable cells was quantified through manual count. Proliferation and osteodifferentiation assays, flow cytometry analysis of cell phenotypes, and osteocalcin release in vitro were performed. The isolation of BFPSCs and DPSCs was successful in 7 out of 12 (58%) and 3 out of 12 (25%) of retrieved samples, respectively. The yield of cells expressing typical stem cell markers and the level of proliferation were higher in BFPSCs than in DPSCs. Both BFP-SCs and DPSCs differentiated into osteoblast-like cells and were able to release a mineralized matrix. The release of osteocalcin, albeit greater for BFPSCs, did not show any significant difference between BFPSCs and DPSCs. The yield of MSCs depends on their site of origin as well as on the protocol adopted for their isolation. Our data show that BFP is a valuable source for the derivation of MSCs that can be used for regenerative treatments

An in situ intercomparison exercise on passive samplers for the monitoring of metals, polycyclic aromatic hydrocarbons and pesticides in surface water

An intercomparison exercise on passive samplers (PSs) was organized in summer 2010 for the measurement of selected metals, polycyclic aromatic hydrocarbons (PAHs) and pesticides in surface waters. Various PSs were used and compared at 2 rivers sites and one marine lagoon. A total of 24 laboratories participated. We present selected significant outputs from this exercise, including discussion on quality assurance and quality control for PSs, the interlaboratory variability of field blanks, time weighted average water concentrations and its uncertainties, the representativity of DGT samples, the ability of PSs to lower limits of detection, PAH fingerprints in various PSs compared with spot samples, and the relevance of the permeability reference compounds (PRC) approach for POCIS with pesticides. These in situ intercomparison exercises should enable to progress on the harmonization of practices for the use of passive sampling, especially for priority chemical monitoring and regulatory programs in compliance with the Water Framework Directive (WFD) and Marine Strategy Framework Directive (MSFD)

SiO2nanoparticles modulate the electrical activity of neuroendocrine cells without exerting genomic effects

Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications, and particularly in the field of nanomedicine, thanks to the high biocompatibility of this material. For their optimal and controlled use, the understanding of the mechanisms elicited by their interaction with the biological target is a prerequisite, especially when dealing with cells particularly vulnerable to environmental stimuli like neurons. Here we have combined different electrophysiological approaches (both at the single cell and at the population level) with a genomic screening in order to analyze, in GT1-7 neuroendocrine cells, the impact of SiO2NPs (50\u2009\ub1\u20093\u2009nm in diameter) on electrical activity and gene expression, providing a detailed analysis of the impact of a nanoparticle on neuronal excitability. We find that 20\u2009\ub5g\u2009mL-1NPs induce depolarization of the membrane potential, with a modulation of the firing of action potentials. Recordings of electrical activity with multielectrode arrays provide further evidence that the NPs evoke a temporary increase in firing frequency, without affecting the functional behavior on a time scale of hours. Finally, NPs incubation up to 24\u2009hours does not induce any change in gene expression