toxic

Of moss and men: Using moss as a bioindicator of toxic heavy metals at the city scale

Air quality is a critical issue affecting the health of billions of people worldwide, yet often little is known about what is in the air we breathe. To reduce air pollution’s health impacts, pollution sources must first be reliably identified. Otherwise, it is impossible to design and effectively enforce environmental standards. However, urban networks of air quality monitors are often too widely spaced to identify the sources of air pollutants, especially for pollutants that do not disperse far from their sources. Developing high-resolution pollution maps with data from these widely spaced monitors is problematic.




toxic

21 health and medical groups speak out against EPA finalizing a rule that could undermine the Mercury and Air Toxics Standards

Today, the U.S. Environmental Protection Agency (EPA) announced a final rule that threatens to undermine the Mercury and Air Toxics Standards. The American Lung Association, Allergy & Asthma Network, Alliance of Nurses for Healthy Environments, American...




toxic

Surface treatment method for a substrate using denatured urushiol derived from Toxicodendron vernicifluum

A method of treating a surface of a substrate using modified urushiol derived from Toxicodendron vernicifluum is provided. More particularly, the reactivity of a hydroxyl group of urushiol extracted from fresh Toxicodendron vernicifluum is removed before the lacquer is used as a UV coating agent for a substrate such as a steel sheet. Therefore, the substrate may have high antibacterial activity, and excellent appearance and functionalities such as far-infrared radiation, blocking of electromagnetic waves, enhanced corrosion resistance, high crosslinking speed when a low content of a photoinitiator is used, excellent surface gloss and high scratch resistance.




toxic

Azo compounds reducing formation and toxicity of amyloid beta aggregation intermediates

The present invention relates to compounds suitable as modulators of protein misfolding and/or protein aggregation. The compounds are particularly suitable as inhibitors of amyloid aggregate formation and/or modulators of amyloid surface properties, and/or as activators of degradation or reduction of amyloid aggregates.




toxic

Conversion of corn gluten meal into a solid article through the use of a non-toxic additive

Disclosed are fast-curing, inexpensive corn-gluten resin compositions, methods for making them, methods for forming them into solid articles. In some embodiments, the resin composition includes corn meal gluten and a non-toxic organic acid.




toxic

High performance, low toxicity hypergolic fuel

A group of tertiary amine azides are useful as hypergolic fuels for hypergolic bipropellant mixtures. The fuels provide higher density impulses than monomethyl hydrazine (MMH) but are less toxic and have lower vapor pressures that MMH. In addition, the fuels have shorter ignition delay times than dimethylaminoethylazide (DMAZ) and other potential reduced toxicity replacements for MMH.




toxic

Flavored Juul E-Cigarettes Contain Unlisted, Toxic Compounds, Yale Study Shows

A new study from Yale University found some users of the popular e-cigarette brand Juul might be inhaling unexpected chemicals.




toxic

Toxic burden

At a time when environmental protections are under more threats than ever, Reveal visits minority communities facing toxic burdens.

Head over to revealnews.org for more of our reporting.

Follow us on Facebook at fb.com/ThisIsReveal and on Twitter @reveal.

And to see some of what you’re hearing, we’re also on Instagram @revealnews.




toxic

Social media can be 'toxic' and 'violent' — so people are trading it for private chats: journalist

Tech journalist Takara Small says people are building private social networks, through group messages with friends and family and interest-based communities, to create a safe space online.





toxic

Landholders in far west NSW warned toxic native plants after cattle deaths

The native desert rice flower plant that appeared on New South Wales properties after widespread rainfall has caused death and serious illness in cattle




toxic

Lumholtz's tree kangaroo blindness mystifies experts, but toxic leaves could be to blame

This kangaroo species normally lives high in the treetops but is now being found in odd places, unable to see and confused, and one ecologist is trying to find out the cause.




toxic

Califonia Communities Against Toxics v. Environmental Protection Agency

(United States DC Circuit) - Petition for review denied. The EPA did not act contrary to the Resource Conservation and Recovery Act in adopting a Transfer-Based Exclusion because hazardous materials are not necessarily "discarded" when they are transferred from a generator to a reclaimer along with payment. The policy was not arbitrary or capricious.




toxic

California Communities Against Toxics v. EPA

(United States DC Circuit) - Dismissed. The Wehrum Memo relating to air quality was not a final agency action, so the court lacked subject matter jurisdiction to hear complaints about its contents.




toxic

Califonia Communities Against Toxics v. Environmental Protection Agency

(United States DC Circuit) - Petition for review denied. The EPA did not act contrary to the Resource Conservation and Recovery Act in adopting a Transfer-Based Exclusion because hazardous materials are not necessarily "discarded" when they are transferred from a generator to a reclaimer along with payment. The policy was not arbitrary or capricious.




toxic

Exosome-mediated protection of auditory hair cells from ototoxic insults

Hearing loss caused by the death of sensory hair cells of the inner ear is an unfortunate side effect for many patients treated with aminoglycoside antibiotics or platinum-containing chemotherapy agents. In animal models, induction of heat shock confers substantial otoprotection against aminoglycoside- and cisplatin-induced hair cell death. In this issue of the JCI, Breglio et al. demonstrate that inner ear tissue released exosomes carrying heat shock protein 70 (HSP70) in response to heat stress. HSP70 acted by a paracrine mechanism that engaged the Toll-like receptor 4 (TLR4) on hair cells to protect them from death. Exosomes and the HSP70/TLR4 pathway could thus provide treatment targets for the protection of hair cells from chemically induced death or from other insults, such as noise.




toxic

BCL-2 antagonism sensitizes cytotoxic T cell–resistant HIV reservoirs to elimination ex vivo

Curing HIV infection will require the elimination of a reservoir of infected CD4+ T cells that persists despite HIV-specific cytotoxic T cell (CTL) responses. Although viral latency is a critical factor in this persistence, recent evidence also suggests a role for intrinsic resistance of reservoir-harboring cells to CTL killing. This resistance may have contributed to negative outcomes of clinical trials, where pharmacologic latency reversal has thus far failed to drive reductions in HIV reservoirs. Through transcriptional profiling, we herein identified overexpression of the prosurvival factor B cell lymphoma 2 (BCL-2) as a distinguishing feature of CD4+ T cells that survived CTL killing. We show that the inducible HIV reservoir was disproportionately present in BCL-2hi subsets in ex vivo CD4+ T cells. Treatment with the BCL-2 antagonist ABT-199 was not sufficient to drive reductions in ex vivo viral reservoirs when tested either alone or with a latency-reversing agent (LRA). However, the triple combination of strong LRAs, HIV-specific T cells, and a BCL-2 antagonist uniquely enabled the depletion of ex vivo viral reservoirs. Our results provide rationale for novel therapeutic approaches targeting HIV cure and, more generally, suggest consideration of BCL-2 antagonism as a means of enhancing CTL immunotherapy in other settings, such as cancer.




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Cytotoxic CD4+ T lymphocytes may induce endothelial cell apoptosis in systemic sclerosis

Systemic sclerosis (SSc) is an autoimmune fibrotic disease whose pathogenesis is poorly understood and lacks effective therapies. We undertook quantitative analyses of T cell infiltrates in the skin of 35 untreated patients with early diffuse SSc and here show that CD4+ cytotoxic T cells and CD8+ T cells contribute prominently to these infiltrates. We also observed an accumulation of apoptotic cells in SSc tissues, suggesting that recurring cell death may contribute to tissue damage and remodeling in this fibrotic disease. HLA-DR–expressing endothelial cells were frequent targets of apoptosis in SSc, consistent with the prominent vasculopathy seen in patients with this disease. A circulating effector population of cytotoxic CD4+ T cells, which exhibited signatures of enhanced metabolic activity, was clonally expanded in patients with systemic sclerosis. These data suggest that cytotoxic T cells may induce the apoptotic death of endothelial and other cells in systemic sclerosis. Cell loss driven by immune cells may be followed by overly exuberant tissue repair processes that lead to fibrosis and tissue dysfunction.




toxic

EPA Announces Cooperative Agreement to Support the National Tribal Toxics Council (NTTC)

WASHINGTON (April 29, 2020) — The U.S.




toxic

Monsanto Merger Migraine: Roundup Is Toxic for Bayer

German multinational Bayer underestimated the risks of acquiring Monsanto. Now, the company is desperately seeking to contain the damage by selling business divisions and cutting jobs. So far, though, none of these moves have helped.




toxic

A year ago, toxic red tide took over Florida’s Gulf Coast. What would it take to stop it next time?

Killing red tide cells en masse can unleash their potent toxin. That means researchers need to get creative.




toxic

Rowing Without Wind; Financial Toxicity Catches Many Unawares; Making 'Cold' Tumors 'Hot'

(MedPage Today) -- "When there is no wind, we row." What a cancer doctor-turned-cancer patient learned from his own patients. (ASCO Connection via KevinMD) Under most circumstances, fewer cancer diagnoses might be good news, but that's not necessarily...




toxic

Review: Smartly scripted 'Tammy's Always Dying' pits mother and daughter in toxic cycle

"Tammy's Always Dying" is a low-key, insightful comic drama about a striving woman and her albatross-like mother, played by Felicity Huffman.




toxic

Steer clear of toxic money-off shopping voucher – it’s a scam



IF YOU get an email or a letter offering a tempting money-off voucher for purchases during quarantine that claims to be from one of the well-known supermarket brands, bin or delete it immediately.




toxic

Plainfield police officer arrested on suspicion of driving while intoxicated

An off-duty Plainfield police officer was arrested Friday night on suspicion of driving while intoxicated.

      




toxic

Brain manganese and the balance between essential roles and neurotoxicity [Molecular Bases of Disease]

Manganese (Mn) is an essential micronutrient required for the normal development of many organs, including the brain. Although its roles as a cofactor in several enzymes and in maintaining optimal physiology are well-known, the overall biological functions of Mn are rather poorly understood. Alterations in body Mn status are associated with altered neuronal physiology and cognition in humans, and either overexposure or (more rarely) insufficiency can cause neurological dysfunction. The resultant balancing act can be viewed as a hormetic U-shaped relationship for biological Mn status and optimal brain health, with changes in the brain leading to physiological effects throughout the body and vice versa. This review discusses Mn homeostasis, biomarkers, molecular mechanisms of cellular transport, and neuropathological changes associated with disruptions of Mn homeostasis, especially in its excess, and identifies gaps in our understanding of the molecular and biochemical mechanisms underlying Mn homeostasis and neurotoxicity.




toxic

Inhibition of the polyamine synthesis enzyme ornithine decarboxylase sensitizes triple-negative breast cancer cells to cytotoxic chemotherapy [Molecular Bases of Disease]

Treatment of patients with triple-negative breast cancer (TNBC) is limited by a lack of effective molecular therapies targeting this disease. Recent studies have identified metabolic alterations in cancer cells that can be targeted to improve responses to standard-of-care chemotherapy regimens. Using MDA-MB-468 and SUM-159PT TNBC cells, along with LC-MS/MS and HPLC metabolomics profiling, we found here that exposure of TNBC cells to the cytotoxic chemotherapy drugs cisplatin and doxorubicin alter arginine and polyamine metabolites. This alteration was because of a reduction in the levels and activity of a rate-limiting polyamine biosynthetic enzyme, ornithine decarboxylase (ODC). Using gene silencing and inhibitor treatments, we determined that the reduction in ODC was mediated by its negative regulator antizyme, targeting ODC to the proteasome for degradation. Treatment with the ODC inhibitor difluoromethylornithine (DFMO) sensitized TNBC cells to chemotherapy, but this was not observed in receptor-positive breast cancer cells. Moreover, TNBC cell lines had greater sensitivity to single-agent DFMO, and ODC levels were elevated in TNBC patient samples. The alterations in polyamine metabolism in response to chemotherapy, as well as DFMO-induced preferential sensitization of TNBC cells to chemotherapy, reported here suggest that ODC may be a targetable metabolic vulnerability in TNBC.




toxic

Tackling Toxic Air Pollution in Cities

Members Event

27 November 2019 - 6:00pm to 7:00pm

Chatham House | 10 St James's Square | London | SW1Y 4LE

Event participants

Camilla Hodgson, Environment Reporter, Financial Times

Dr Benjamin Barratt, Senior Lecturer in Chinese Environment, KCL

Dr Susannah Stanway MBChB MSc FRCP MD, Consultant in Medical Oncology Royal Marsden NHS Foundation Trust

Elliot Treharne, Head of Air Quality, Greater London Authority

Chair: Rob Yates, Head, Centre on Global Health Security, Chatham House

Air pollution has been classified as a cancer-causing agent with evidence showing an increased risk of lung cancer associated with increasing levels of exposure to outdoor air pollution and particulate matter.

Air pollution is also known to increase risks for other diseases, especially respiratory and heart diseases, and studies show that levels of exposure to air pollution have increased significantly in some parts of the world - mostly in rapidly industrializing countries with large populations.

In coordination with London Global Cancer Week partner organizations, this event outlines the evidence linking air pollution and cancer rates in London and other major cities.

Panellists provide a 360° picture of the impact of the rising incidence of cancer across the world, the challenges the cancer pandemic poses to the implementation of universal health coverage and the existing UK contribution to strengthening capacity in cancer management and research in developing countries.

Department/project

Members Events Team




toxic

Disruption of endoplasmic reticulum structure and integrity in lipotoxic cell death

Nica M. Borradaile
Dec 1, 2006; 47:2726-2737
Research Articles




toxic

Brain manganese and the balance between essential roles and neurotoxicity [Molecular Bases of Disease]

Manganese (Mn) is an essential micronutrient required for the normal development of many organs, including the brain. Although its roles as a cofactor in several enzymes and in maintaining optimal physiology are well-known, the overall biological functions of Mn are rather poorly understood. Alterations in body Mn status are associated with altered neuronal physiology and cognition in humans, and either overexposure or (more rarely) insufficiency can cause neurological dysfunction. The resultant balancing act can be viewed as a hormetic U-shaped relationship for biological Mn status and optimal brain health, with changes in the brain leading to physiological effects throughout the body and vice versa. This review discusses Mn homeostasis, biomarkers, molecular mechanisms of cellular transport, and neuropathological changes associated with disruptions of Mn homeostasis, especially in its excess, and identifies gaps in our understanding of the molecular and biochemical mechanisms underlying Mn homeostasis and neurotoxicity.




toxic

Tackling Toxic Air Pollution in Cities




toxic

Decreased Immunoglobulin G Core Fucosylation, A Player in Antibody-dependent Cell-mediated Cytotoxicity, is Associated with Autoimmune Thyroid Diseases [Research]

Autoimmune thyroid diseases (AITD) are the most common group of autoimmune diseases, associated with lymphocyte infiltration and the production of thyroid autoantibodies, like thyroid peroxidase antibodies (TPOAb), in the thyroid gland. Immunoglobulins and cell-surface receptors are glycoproteins with distinctive glycosylation patterns that play a structural role in maintaining and modulating their functions. We investigated associations of total circulating IgG and peripheral blood mononuclear cells glycosylation with AITD and the influence of genetic background in a case-control study with several independent cohorts and over 3,000 individuals in total. The study revealed an inverse association of IgG core fucosylation with TPOAb and AITD, as well as decreased peripheral blood mononuclear cells antennary α1,2 fucosylation in AITD, but no shared genetic variance between AITD and glycosylation. These data suggest that the decreased level of IgG core fucosylation is a risk factor for AITD that promotes antibody-dependent cell-mediated cytotoxicity previously associated with TPOAb levels.




toxic

Tackling Toxic Air Pollution in Cities

Members Event

27 November 2019 - 6:00pm to 7:00pm

Chatham House | 10 St James's Square | London | SW1Y 4LE

Event participants

Camilla Hodgson, Environment Reporter, Financial Times

Dr Benjamin Barratt, Senior Lecturer in Chinese Environment, KCL

Dr Susannah Stanway MBChB MSc FRCP MD, Consultant in Medical Oncology Royal Marsden NHS Foundation Trust

Elliot Treharne, Head of Air Quality, Greater London Authority

Chair: Rob Yates, Head, Centre on Global Health Security, Chatham House

Air pollution has been classified as a cancer-causing agent with evidence showing an increased risk of lung cancer associated with increasing levels of exposure to outdoor air pollution and particulate matter.

Air pollution is also known to increase risks for other diseases, especially respiratory and heart diseases, and studies show that levels of exposure to air pollution have increased significantly in some parts of the world - mostly in rapidly industrializing countries with large populations.

In coordination with London Global Cancer Week partner organizations, this event outlines the evidence linking air pollution and cancer rates in London and other major cities.

Panellists provide a 360° picture of the impact of the rising incidence of cancer across the world, the challenges the cancer pandemic poses to the implementation of universal health coverage and the existing UK contribution to strengthening capacity in cancer management and research in developing countries.

Department/project

Members Events Team




toxic

Tackling Toxic Air Pollution in Cities

Members Event

27 November 2019 - 6:00pm to 7:00pm

Chatham House | 10 St James's Square | London | SW1Y 4LE

Event participants

Camilla Hodgson, Environment Reporter, Financial Times

Dr Benjamin Barratt, Senior Lecturer in Chinese Environment, KCL

Dr Susannah Stanway MBChB MSc FRCP MD, Consultant in Medical Oncology Royal Marsden NHS Foundation Trust

Elliot Treharne, Head of Air Quality, Greater London Authority

Chair: Rob Yates, Head, Centre on Global Health Security, Chatham House

Air pollution has been classified as a cancer-causing agent with evidence showing an increased risk of lung cancer associated with increasing levels of exposure to outdoor air pollution and particulate matter.

Air pollution is also known to increase risks for other diseases, especially respiratory and heart diseases, and studies show that levels of exposure to air pollution have increased significantly in some parts of the world - mostly in rapidly industrializing countries with large populations.

In coordination with London Global Cancer Week partner organizations, this event outlines the evidence linking air pollution and cancer rates in London and other major cities.

Panellists provide a 360° picture of the impact of the rising incidence of cancer across the world, the challenges the cancer pandemic poses to the implementation of universal health coverage and the existing UK contribution to strengthening capacity in cancer management and research in developing countries.

Department/project

Members Events Team




toxic

Filtering out toxic chromium from water

(Ecole Polytechnique Fédérale de Lausanne) EPFL chemists have developed sponges to capture various target substances, like gold, mercury and lead, dissolved in solution. The sponges are actually porous crystals called metal organic frameworks, and now one exists for capturing toxic hexavalent chromium from water.




toxic

Cancer survivors' experiences with financial toxicity

(Wiley) A recent Psycho-Oncology analysis of published studies found that few cancer survivors received financial information support from healthcare facilities during their initial treatment, even though cancer-related financial toxicity has multiple impacts on survivors' health and quality of life.




toxic

Arginine in C9ORF72 Dipolypeptides Mediates Promiscuous Proteome Binding and Multiple Modes of Toxicity

Mona Radwan
Apr 1, 2020; 19:640-654
Research




toxic

PARP-1-targeted Auger emitters display high-LET cytotoxic properties in vitro but show limited therapeutic utility in solid tumor models of human neuroblastoma

The currently available therapeutic radiopharmaceutical for high-risk neuroblastoma, 131I-MIBG, is ineffective at targeting micrometastases due to the low linear energy transfer (LET) properties of high-energy beta particles. In contrast, Auger radiation has high-LET properties with nanometer ranges in tissue, efficiently causing DNA damage when emitted in close proximity to DNA. The aim of this study was to evaluate the cytotoxicity of targeted Auger therapy in pre-clinical models of high-risk neuroblastoma. Methods: Using a radiolabeled poly(ADP-ribose) polymerase (PARP) inhibitor, 125I-KX1, we delivered an Auger emitter iodine-125 to PARP-1: a chromatin-binding enzyme overexpressed in neuroblastoma. In vitro cytotoxicity of 125I-KX1 was assessed in nineteen neuroblastoma cell lines, followed by in-depth pharmacological analysis in a sensitive and resistant pair of cell lines. Immunofluorescence microscopy was used to characterize 125I-KX1-induced DNA damage. Finally, in vitro/in vivo microdosimetry was modeled from experimentally derived pharmacological variables. Results: 125I-KX1 was highly cytotoxic in vitro across a panel of neuroblastoma cell lines, directly causing double strand DNA breaks. Based on subcellular dosimetry, 125I-KX1 was approximately twice as effective compared to 131I-KX1, whereas cytoplasmic 125I-MIBG demonstrated low biological effectiveness. Despite the ability to deliver focused radiation dose to the cell nuclei, 125I-KX1 remained less effective than its alpha-emitting analog 211At-MM4, and required significantly higher activity for equivalent in vivo efficacy based on tumor microdosimetry. Conclusion: Chromatin-targeted Auger therapy is lethal to high-risk neuroblastoma cells with potential use in micrometastatic disease. This study provides the first evidence for cellular lethality from a PARP-1 targeted Auger emitter, calling for further investigation into targeted Auger therapy.




toxic

Arginine in C9ORF72 Dipolypeptides Mediates Promiscuous Proteome Binding and Multiple Modes of Toxicity [Research]

C9ORF72-associated Motor Neuron Disease patients feature abnormal expression of 5 dipeptide repeat (DPR) polymers. Here we used quantitative proteomics in a mouse neuronal-like cell line (Neuro2a) to demonstrate that the Arg residues in the most toxic DPRS, PR and GR, leads to a promiscuous binding to the proteome compared with a relative sparse binding of the more inert AP and GA. Notable targets included ribosomal proteins, translation initiation factors and translation elongation factors. PR and GR comprising more than 10 repeats appeared to robustly stall on ribosomes during translation suggesting Arg-rich peptide domains can electrostatically jam the ribosome exit tunnel during synthesis. Poly-GR also recruited arginine methylases, induced hypomethylation of endogenous proteins, and induced a profound destabilization of the actin cytoskeleton. Our findings point to arginine in GR and PR polymers as multivalent toxins to translation as well as arginine methylation that may explain the dysfunction of biological processes including ribosome biogenesis, mRNA splicing and cytoskeleton assembly.




toxic

Decreased Immunoglobulin G Core Fucosylation, A Player in Antibody-dependent Cell-mediated Cytotoxicity, is Associated with Autoimmune Thyroid Diseases [Research]

Autoimmune thyroid diseases (AITD) are the most common group of autoimmune diseases, associated with lymphocyte infiltration and the production of thyroid autoantibodies, like thyroid peroxidase antibodies (TPOAb), in the thyroid gland. Immunoglobulins and cell-surface receptors are glycoproteins with distinctive glycosylation patterns that play a structural role in maintaining and modulating their functions. We investigated associations of total circulating IgG and peripheral blood mononuclear cells glycosylation with AITD and the influence of genetic background in a case-control study with several independent cohorts and over 3,000 individuals in total. The study revealed an inverse association of IgG core fucosylation with TPOAb and AITD, as well as decreased peripheral blood mononuclear cells antennary α1,2 fucosylation in AITD, but no shared genetic variance between AITD and glycosylation. These data suggest that the decreased level of IgG core fucosylation is a risk factor for AITD that promotes antibody-dependent cell-mediated cytotoxicity previously associated with TPOAb levels.




toxic

Inhibition of the polyamine synthesis enzyme ornithine decarboxylase sensitizes triple-negative breast cancer cells to cytotoxic chemotherapy [Molecular Bases of Disease]

Treatment of patients with triple-negative breast cancer (TNBC) is limited by a lack of effective molecular therapies targeting this disease. Recent studies have identified metabolic alterations in cancer cells that can be targeted to improve responses to standard-of-care chemotherapy regimens. Using MDA-MB-468 and SUM-159PT TNBC cells, along with LC-MS/MS and HPLC metabolomics profiling, we found here that exposure of TNBC cells to the cytotoxic chemotherapy drugs cisplatin and doxorubicin alter arginine and polyamine metabolites. This alteration was because of a reduction in the levels and activity of a rate-limiting polyamine biosynthetic enzyme, ornithine decarboxylase (ODC). Using gene silencing and inhibitor treatments, we determined that the reduction in ODC was mediated by its negative regulator antizyme, targeting ODC to the proteasome for degradation. Treatment with the ODC inhibitor difluoromethylornithine (DFMO) sensitized TNBC cells to chemotherapy, but this was not observed in receptor-positive breast cancer cells. Moreover, TNBC cell lines had greater sensitivity to single-agent DFMO, and ODC levels were elevated in TNBC patient samples. The alterations in polyamine metabolism in response to chemotherapy, as well as DFMO-induced preferential sensitization of TNBC cells to chemotherapy, reported here suggest that ODC may be a targetable metabolic vulnerability in TNBC.




toxic

Excitotoxicity and Overnutrition Additively Impair Metabolic Function and Identity of Pancreatic {beta}-cells

A sustained increase in intracellular Ca2+ concentration (referred to herein as excitotoxicity), brought on by chronic metabolic stress, may contribute to pancreatic β-cell failure. To determine the additive effects of excitotoxicity and overnutrition on β-cell function and gene expression, we analyzed the impact of a high fat diet (HFD) on Abcc8 knock-out mice. Excitotoxicity caused β-cells to be more susceptible to HFD-induced impairment of glucose homeostasis, and these effects were mitigated by verapamil, a Ca2+ channel blocker. Excitotoxicity, overnutrition and the combination of both stresses caused similar but distinct alterations in the β-cell transcriptome, including additive increases in genes associated with mitochondrial energy metabolism, fatty acid β-oxidation and mitochondrial biogenesis, and their key regulator Ppargc1a. Overnutrition worsened excitotoxicity-induced mitochondrial dysfunction, increasing metabolic inflexibility and mitochondrial damage. In addition, excitotoxicity and overnutrition, individually and together, impaired both β-cell function and identity by reducing expression of genes important for insulin secretion, cell polarity, cell junction, cilia, cytoskeleton, vesicular trafficking, and regulation of β-cell epigenetic and transcriptional program. Sex had an impact on all β-cell responses, with male animals exhibiting greater metabolic stress-induced impairments than females. Together, these findings indicate that a sustained increase in intracellular Ca2+, by altering mitochondrial function and impairing β-cell identity, augments overnutrition-induced β-cell failure.




toxic

Nutrient-Induced Metabolic Stress, Adaptation, Detoxification, and Toxicity in the Pancreatic {beta}-Cell

Paraphrasing the Swiss physician and father of toxicology Paracelsus (1493–1541) on chemical agents used as therapeutics, "the dose makes the poison," it is now realized that this aptly applies to the calorigenic nutrients. The case here is the pancreatic islet β-cell presented with excessive levels of nutrients such as glucose, lipids, and amino acids. The short-term effects these nutrients exert on the β-cell are enhanced insulin biosynthesis and secretion and changes in glucose sensitivity. However, chronic fuel surfeit triggers additional compensatory and adaptive mechanisms by β-cells to cope with the increased insulin demand or to protect itself. When these mechanisms fail, toxicity due to the nutrient surplus ensues, leading to β-cell dysfunction, dedifferentiation, and apoptosis. The terms glucotoxicity, lipotoxicity, and glucolipotoxicity have been widely used, but there is some confusion as to what they mean precisely and which is most appropriate for a given situation. Here we address the gluco-, lipo-, and glucolipo-toxicities in β-cells by assessing the evidence both for and against each of them. We also discuss potential mechanisms and defend the view that many of the identified "toxic" effects of nutrient excess, which may also include amino acids, are in fact beneficial adaptive processes. In addition, candidate fuel-excess detoxification pathways are evaluated. Finally, we propose that a more general term should be used for the in vivo situation of overweight-associated type 2 diabetes reflecting both the adaptive and toxic processes to mixed calorigenic nutrients excess: "nutrient-induced metabolic stress" or, in brief, "nutri-stress."




toxic

Glucolipotoxicity, {beta}-Cells, and Diabetes: The Emperor Has No Clothes

Reduction of β-cell mass and function is central to the pathogenesis of type 2 diabetes. The terms glucotoxicity, lipotoxicity, and glucolipotoxicity are used to describe potentially responsible processes. The premise is that chronically elevated glucose levels are toxic to β-cells, that elevated lipid levels in the form of circulating free fatty acids (FFA) also have toxic effects, and that the combination of the two, glucolipotoxicity, is particularly harmful. Much work has shown that high concentrations of FFA can be very damaging to β-cells when used for in vitro experiments, and when infused in large amounts in humans and rodents they produce suppression of insulin secretion. The purpose of this Perspective is to raise doubts about whether the FFA levels found in real-life situations are ever high enough to cause problems. Evidence supporting the importance of glucotoxicity is strong because there is such a tight correlation between defective insulin secretion and rising glucose levels. However, there is virtually no convincing evidence that the alterations in FFA levels occurring during progression to diabetes are pathogenic. Thus, the terms lipotoxicity and glucolipotoxicity should be used with great caution, if at all, because evidence supporting their importance has not yet emerged.




toxic

A Phenotypic Screen Identifies Calcium Overload as a Key Mechanism of {beta}-Cell Glucolipotoxicity

Jennifer Vogel
May 1, 2020; 69:1032-1041
Pharmacology and Therapeutics




toxic

Lipotoxicity in the Pathogenesis of Obesity-Dependent NIDDM: Genetic and Clinical Implications

Roger H Unger
Aug 1, 1995; 44:863-870
Perspectives in Diabetes




toxic

Liver ChREBP Protects Against Fructose-Induced Glycogenic Hepatotoxicity by Regulating L-Type Pyruvate Kinase

Excessive fructose consumption is closely linked to the pathogenesis of metabolic disease. Carbohydrate response element-binding protein (ChREBP) is a transcription factor essential for fructose tolerance in mice. However, the functional significance of liver ChREBP in fructose metabolism remains unclear. Here, we show that liver ChREBP protects mice against fructose-induced hepatotoxicity by regulating liver glycogen metabolism and ATP homeostasis. Liver-specific ablation of ChREBP did not compromise fructose tolerance, but rather caused severe transaminitis and hepatomegaly with massive glycogen overload in mice fed a high-fructose diet, while no obvious inflammation, cell death, or fibrosis was detected in the liver. In addition, liver ATP contents were significantly decreased by ChREBP deficiency in the fed state, which was rendered more pronounced by fructose feeding. Mechanistically, liver contents of glucose-6-phosphate (G6P), an allosteric activator of glycogen synthase, were markedly increased in the absence of liver ChREBP, while fasting-induced glycogen breakdown was not compromised. Furthermore, hepatic overexpression of LPK, a ChREBP target gene in glycolysis, could effectively rescue glycogen overload and ATP reduction, as well as mitigate fructose-induced hepatotoxicity in ChREBP-deficient mice. Taken together, our findings establish a critical role of liver ChREBP in coping with hepatic fructose stress and protecting from hepatotoxicity by regulating LPK.




toxic

Die Sublimatintoxication : Beitrage zur Geschichte, Klinik und pathologischen Anatomie derselben, nebst experimentellen Untersuchungen zur Theorie ihres Wesens / von E. Kaufmann.

Breslau : W. Koebner, 1888.




toxic

Du chloro-brightisme : toxicité urinaire et oxydations dans la chlorose / par P. Chatin.

Paris : J.-B. Baillière, 1894.




toxic

Essai clinique et expérimental sur la fièvre des tuberculeux (toxicité des crachats, toxicité des urines) / par Le Docteur Edouard Chretien.

Paris : Steinheil, 1896.