Evidence of cadmium and mercury involvement in the Aβ42 aggregation process

Ab42 is a small peptide formed from 42 aminoacids that presents a great propensity to aggregate until it forms fibrils. Ab42 aggregation and fibrillation are very complex processes whose molecular mechanisms seem to depend on characteristics intrinsic to the peptide molecule, as well as extrinsic factors. Peptide concentration, mean pH and several substances, including metal ions, are principal extrinsic factors for the oligomerization process. Different metals affect the aggregation of the Ab42 molecule, and their toxicity favours the misfolding and aggregation of the peptide. In this study, we evaluate the effect of different concentrations of Cd2+ and Hg2+ on the Aβ42 peptide in solution by different methods. The toxicity of Aβ42 was evaluated with the MTT assay, while the aggregation process was monitored by single-channel measurements, electrophoresis and western blot. Cd2+ and Hg2+ seem to favour the formation of high-molecular-weight aggregates, to decrease ion channel turnover inside the membrane and to significantly increase Aβ42 toxicity

Efficacy of ketamine in refractory convulsive status epilepticus in children: A protocol for a sequential design, multicentre, randomised, controlled, open-label, non-profit trial (KETASER01)

Introduction: Status epilepticus (SE) is a lifethreatening neurological emergency. SE lasting longer than 120 min and not responding to first-line and second-line antiepileptic drugs is defined as 'refractory' (RCSE) and requires intensive care unit treatment. There is currently neither evidence nor consensus to guide either the optimal choice of therapy or treatment goals for RCSE, which is generally treated with coma induction using conventional anaesthetics (high dose midazolam, thiopental and/or propofol). Increasing evidence indicates that ketamine (KE), a strong N-methyl-D-aspartate glutamate receptor antagonist, may be effective in treating RCSE. We hypothesised that intravenous KE is more efficacious and safer than conventional anaesthetics in treating RCSE. Methods and analysis: A multicentre, randomised, controlled, open-label, non-profit, sequentially designed study will be conducted to assess the efficacy of KE compared with conventional anaesthetics in the treatment of RCSE in children. 10 Italian centres/ hospitals are involved in enrolling 57 patients aged 1 month to 18 years with RCSE. Primary outcome is the resolution of SE up to 24 hours after withdrawal of therapy and is updated for each patient treated according to the sequential method. Ethics and dissemination: The study received ethical approval from the Tuscan Paediatric Ethics Committee (12/2015). The results of this study will be published in peer-reviewed journals and presented at international conferences

Evaluation of the Potential Protective Effect of Ellagic Acid against Heavy Metal (Cadmium, Mercury, and Lead) Toxicity in SH-SY5Y Neuroblastoma Cells

: Ellagic acid (EA), a polyphenolic constituent of plant origin, has been thoroughly investigated for its hypothesised pharmacological properties among which antioxidant and neuroprotective activities are included. The present study was designed to explore whether EA could attenuate heavy metal (cadmium, mercury, and lead)-induced neurotoxicity in SH-SY5Y cells, which were utilized as a model system for brain cells. MTT and LDH assays were performed to examine the viability of the SH-SY5Y cells after exposure to Cd, Hg, and Pb (either individually or in combination with EA) as well as the effects of necrotic cell death, respectively. Furthermore, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), a cell-based assay, was performed to determine whether EA could protect SH-SY5Y from heavy metal-induced oxidative stress. Results allowed us to assess the capability of EA to enhance the number of viable SH-SY5Y cells after exposure to heavy metal toxicity. Pre-treatment with EA showed a considerable, concentration-dependent, cytoprotective effect, particularly against Cd2+-induced toxicity. This effect was confirmed through the reduction of LDH release after the simultaneous cell treatment with Cd2+ and EA compared with Cd2+-treated cells. Furthermore, a significant, concentration-dependent decrease in reactive oxygen species (ROS) production, induced by H2O2 or heavy metals, was observed in the same model. Overall, the obtained results provide further insight into the protective role of EA against heavy metal-induced neurotoxicity and oxidative stress, thus indicating the potential beneficial effects of the consumption of EA-rich foods. However, to confirm its effects, well-designed human randomized controlled trials are needed to fill the existing gap between experimental and clinical research

The Effect of Calcium Ions on hIAPP Channel Activity: Possible Implications in T2DM

The calcium ion (Ca2+) has been linked to type 2 diabetes mellitus (T2DM), although the role of Ca2+ in this disorder is the subject of intense investigation. Serum Ca2+ dyshomeostasis is associated with the development of insulin resistance, reduced insulin sensitivity, and impaired glucose tolerance. However, the molecular mechanisms involving Ca2+ ions in pancreatic β-cell loss and subsequently in T2DM remain poorly understood. Implicated in the decline in β-cell functions are aggregates of human islet amyloid polypeptide (hIAPP), a small peptide secreted by β-cells that shows a strong tendency to self-aggregate into β-sheet-rich aggregates that evolve toward the formation of amyloid deposits and mature fibrils. The soluble oligomers of hIAPP can permeabilize the cell membrane by interacting with bilayer lipids. Our study aimed to evaluate the effect of Ca2+ on the ability of the peptide to incorporate and form ion channels in zwitterionic planar lipid membranes (PLMs) composed of palmitoyl-oleoyl-phosphatidylcholine (POPC) and on the aggregation process of hIAPP molecules in solution. Our results may help to clarify the link between Ca2+ ions, hIAPP peptide, and consequently the pathophysiology of T2DM

Phenolic Compounds from Tropea Red Onion as Dietary Agents for Protection against Heavy Metals Toxicity

Abstract: The present study aims to highlight the cell protective effect of Tropea red onion (TRO) hydroalcoholic extract and some of its components against “non-essential” heavy metals. For this purpose, the cytoprotective roles of cyanidin, cyanidin-3-O-glucoside and quercetin against Cd, Hg and Pb and of TRO extract against Hg and Pb have been investigated, and data are reported here. To the best of our knowledge, this is the first detailed evaluation of the protective effect against cell damage induced by “non-essential” heavy metals through the simultaneous administration of cyanidin, cyanidin-3-O-glucoside and quercetin with CdCl2, HgCl2 or PbCl2 and the TRO extract against HgCl2 and PbCl2. Present data are also compared with our previous results from the TRO extract against Cd. The antioxidant capacity of the extract was also determined by the ferric reducing antioxidant power (FRAP) and the bovine brain peroxidation assay. Both of the assays indicated a good antioxidant capacity of the extract. Cell viability and the impact on necrotic cell death were examined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) test and lactate dehydrogenase (LDH) release assay. After 24 h of exposure, Caco-2 cell viability decreased by approximately 50% at 0.25 μM for Cd, Hg and Pb and, after 72 h, the ranking order of “non-essential” heavy metal toxicity on cell viability was PbCl2 > CdCl2 > HgCl2. Cell viability was assessed by treating the cells with the biomolecules at doses of 25, 50 and 100 μg/mL for 24 and 72 h. The same analysis was carried out on Caco-2 cells treated with combinations of TRO extract, cyanidin, cyanidin-3-O-glucoside, or quercetin and “non-essential” heavy metals. Treatments with the bioactive metabolites did not significantly improve cell viability. The identical treatment of Caco-2 cells produced instead LDH release, suggesting a decrease in cell viability. Consistently with the finding that TRO extract showed a good antioxidant activity, we suggest that its higher cytotoxicity, compared to that of the individual assayed phytochemicals, may be derived by the combined antioxidant and chelating properties of all the molecules present in the extract. Therefore, from all the acquired experimental evidence, it appears that the TRO extract may be a better promising protective agent against the toxic effect of Cd, Hg and Pb compared to its bioactive metabolites

Potential Protective Effects of Spirulina (Spirulina platensis) against In Vitro Toxicity Induced by Heavy Metals (Cadmium, Mercury, and Lead) on SH-SY5Y Neuroblastoma Cells

Spirulina, a filamentous microalga, is used all over the world as a nutraceutical dietary supplement. Recent studies have focused on examining its chelating activity and antioxidant properties, especially as a candidate for protection against neurotoxicity caused by heavy metals. The MTT test and LDH assay were used to examine the viability of the SH-SY5Y cells for 24, 48, and 72 h, to Cd, Hg, and Pb, individually or in combination with Spirulina, and the effects of necrotic cell death. In comparison to the control group, the viability of SH-SY5Y cells decreased after 24 h of exposure, with Cd being more toxic than Hg and Pb being less lethal. The effects of heavy metal toxicity on cell survival were ranked in order after 72 h under identical experimental circumstances as follows: Hg, Pb, and Cd. The viability of the cells was then tested after being exposed to Spirulina at doses of 5 at 50 (%v/v) for 24, 48, and 72 h, respectively. SH-SY5Y cells that had been treated with mixtures of heavy metals and Spirulina underwent the same assay. Cell viability is considerably increased by using Spirulina treatments at the prescribed periods and doses. Instead, the same procedure, when applied to SH-SY5Y cells, caused the release of LDH, which is consistent with the reduction in cell viability. We demonstrated for the first time, considering all the available data, that Spirulina 5, 25, and 50 (%v/v) enhanced the number of viable SH-SY5Y cells utilized as a model system for brain cells. Overall, the data from the present study provide a first insight into the promising positive role of Spirulina against the potentially toxic effects of metals

Interaction of quercetin, cyanidin, and their O-glucosides with planar lipid models: implications for their biological effects

Flavonoids are specialized metabolites produced by plants, as free aglycones or as glycosylated derivatives, which are particularly endowed with a variety of beneficial ealth properties. The antioxidant, anti-inflammatory, antimicrobial, anticancer, antifungal, antiviral, anti-Alzheimer’s, anti-obesity, antidiabetic, and antihypertensive effects of flavonoids are now known. These bioactive phytochemicals have been shown to act on different molecular targets in cells including the plasma membrane. Due to their polyhydroxylated structure, lipophilicity, and planar conformation, they can either bind at the bilayer interface or interact with the hydrophobic fatty acid tails of the membrane. The interaction of quercetin, cyanidin, and their O-glucosides with planar lipid membranes (PLMs) similar in composition to those of the intestine was monitored using an electrophysiological approach. The obtained results show that the tested flavonoids interact with PLM and form conductive units. The modality of interaction with the lipids of the bilayer and the alteration of the biophysical parameters of PLMs induced by the tested substances provided information on their location in the membrane, helping to elucidate the mechanism of action which underlies some pharmacological properties of flavonoids. To our knowledge, the interaction of quercetin, cyanidin, and their O-glucosides with PLM surrogates of the intestinal membrane has never been previously monitored

Phytochemicals with potential anti-obesity properties

Incidence of obesity has reached an alarming rate worldwide. Obesity is the most prevalent nutritional disease and a major public health problem both in developed and undeveloped countries increasing the risk of metabolic disorders, chronic and cardiovascular diseases. It has been shown that obesity is associated with a chronic inflammatory status in adipose tissue and activation of oxidative stress. In addition, it involves a disfunctional intestinal barrier inducing alteration in its permeability. Plants provide a major dietary source of phytochemicals with anti-obesity potential since many of them, having antioxidant properties, should be able to relieve oxidative stress resulting from inflammation. In continuation of our studies on plants as a supply of valuable compounds with anti-obesity potential, we have investigated by a classical electrophysiology approach the effects of selected plant extracts on Model Planar Lipid Membranes (PLMs) made up of dioleoyl-phosphatidylserine:dioleoyl-phosphatidylethanolamine:palmitoyl-oleoylphosphatidylcholine (27:27:18, w:w:w), a surrogate of intestinal membranes. In particular, the hydroalcholic (70% EtOH) extract from the dry tunics of A. cepa var. Tropea was effective in forming channel-like pathways in the lipid bilayer. Electrophysiological data demonstrated that the extract was able to interact with the PLMs forming stable pores. This effect was also detectable with quercetin, the main component of the extract, that was able to interact with the PLMs and form stable pores in the ranges of applied voltages from 60 to 20 mV and from -60 to -20mV. The conductance values seemed to be inversely dependent on applied voltage thus suggesting that quercetin like the whole extract of A.cepa forms aqueous ion pathways thus modulating membrane permeability. Very interestingly, glycosylation of the molecule resulted in loss of activity

Antioxidant activity and protective effect of the outer scales hydroalcoholic extract of Allium cepa L. var. Tropea on toxicity damage induced by Cadmium in Caco-2 cells

The characterization of bioactive metabolites and the protective effects against Cadmium (Cd) of the hydroalcoholic extract from Allium cepa var. Tropea (Tropea red onion) in human Caco-2 colon adenocarcinoma cells and in vitro antioxidant effects were investigated. Tropea red onion extract showed high levels of bioactive compounds and a strong activity as radical scavenger and inhibitor of lipid peroxidation. The most abundant specialized metabolites were quercetin derivatives. In addition, the extract inhibited NO release in a dosedependent manner. Exposure of Cd treated human Caco-2 cells to the Tropea red onion extract resulted in a higher cytoprotection with a significant falloff of cells damage produced by Cd. The effect of Tropea red onion evaluated with the MTT assay and LDH test, was time-dependent and more evident after 24h of treatment. Caco-2 cells treated with the Tropea red onion extract and CdCl2 at 24h showed a significant cytoprotection at concentrations equal to 50 μg/mL + 25 μM and 100 μg/mL + 25 μM while at 72h at a concentration of 25 μg/mL + 25 μM. We observed with MTT and LDH assays that treatment of cells with Tropea red onion extract at 24h was able to significantly prevent Cd-induced cytotoxicity alon