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1.
Cell Rep ; 43(6): 114243, 2024 May 27.
Article in English | MEDLINE | ID: mdl-38805398

ABSTRACT

Xeroderma pigmentosum (XP) is caused by defective nucleotide excision repair of DNA damage. This results in hypersensitivity to ultraviolet light and increased skin cancer risk, as sunlight-induced photoproducts remain unrepaired. However, many XP patients also display early-onset neurodegeneration, which leads to premature death. The mechanism of neurodegeneration is unknown. Here, we investigate XP neurodegeneration using pluripotent stem cells derived from XP patients and healthy relatives, performing functional multi-omics on samples during neuronal differentiation. We show substantially increased levels of 5',8-cyclopurine and 8-oxopurine in XP neuronal DNA secondary to marked oxidative stress. Furthermore, we find that the endoplasmic reticulum stress response is upregulated and reversal of the mutant genotype is associated with phenotypic rescue. Critically, XP neurons exhibit inappropriate downregulation of the protein clearance ubiquitin-proteasome system (UPS). Chemical enhancement of UPS activity in XP neuronal models improves phenotypes, albeit inadequately. Although more work is required, this study presents insights with intervention potential.

2.
Commun Biol ; 7(1): 497, 2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38658677

ABSTRACT

Most lung cancer patients with metastatic cancer eventually relapse with drug-resistant disease following treatment and EGFR mutant lung cancer is no exception. Genome-wide CRISPR screens, to either knock out or overexpress all protein-coding genes in cancer cell lines, revealed the landscape of pathways that cause resistance to the EGFR inhibitors osimertinib or gefitinib in EGFR mutant lung cancer. Among the most recurrent resistance genes were those that regulate the Hippo pathway. Following osimertinib treatment a subpopulation of cancer cells are able to survive and over time develop stable resistance. These 'persister' cells can exploit non-genetic (transcriptional) programs that enable cancer cells to survive drug treatment. Using genetic and pharmacologic tools we identified Hippo signalling as an important non-genetic mechanism of cell survival following osimertinib treatment. Further, we show that combinatorial targeting of the Hippo pathway and EGFR is highly effective in EGFR mutant lung cancer cells and patient-derived organoids, suggesting a new therapeutic strategy for EGFR mutant lung cancer patients.


Subject(s)
Acrylamides , Drug Resistance, Neoplasm , ErbB Receptors , Indoles , Lung Neoplasms , Mutation , Pyrimidines , Transcription Factors , Humans , Lung Neoplasms/genetics , Lung Neoplasms/drug therapy , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , ErbB Receptors/genetics , ErbB Receptors/metabolism , Drug Resistance, Neoplasm/genetics , Transcription Factors/genetics , Transcription Factors/metabolism , Cell Line, Tumor , Acrylamides/pharmacology , Acrylamides/therapeutic use , YAP-Signaling Proteins/metabolism , YAP-Signaling Proteins/genetics , Aniline Compounds/pharmacology , Aniline Compounds/therapeutic use , Gefitinib/pharmacology , Hippo Signaling Pathway , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Signal Transduction , TEA Domain Transcription Factors , Protein Kinase Inhibitors/pharmacology , Antineoplastic Agents/pharmacology , Clustered Regularly Interspaced Short Palindromic Repeats , CRISPR-Cas Systems
3.
Scand J Pain ; 24(1)2024 Jan 01.
Article in English | MEDLINE | ID: mdl-38126203

ABSTRACT

OBJECTIVES: To systematically review the existing literature for evidence of efficacy around interventions in the management of persistent pain post radiotherapy for head and neck cancers. METHODS: A systematic review of the literature was conducted to assess the effectiveness and safety of interventions for the management of persistent post-radiotherapy pain in head and neck cancers. The primary outcome evaluated whether an intervention resulted in a reduction in pain which was determined using validated pain tools. RESULTS: Two randomised controlled trials involving 196 participants fulfilled the inclusion criteria, one evaluating the effect of hypnotherapy and the other evaluating the effect of pregabalin on radiotherapy related pain in head and neck cancer patients. In one study by Thuma et al. (2016) there was a decrease in pain scores in the hypnotherapy group (p<0.001). In the other study, by Jiang et al. (2018) patients treated with pregabalin had a greater reduction in pain intensity, pain severity and a reduction in pain functional interference (p<0.001). CONCLUSIONS: The findings of our review suggest that in chronic post-radiotherapy pain for head and neck cancers there is very-low level evidence for the use of hypnotherapy in reducing pain scores and for the use of pregabalin in reducing pain intensity, severity, functional interference and psychological distress with significant improvement in quality of life.


Subject(s)
Chronic Pain , Head and Neck Neoplasms , Humans , Pain Management , Pregabalin/therapeutic use , Quality of Life , Head and Neck Neoplasms/radiotherapy , Chronic Pain/drug therapy , Chronic Pain/etiology
4.
Int J Mol Sci ; 24(2)2023 Jan 16.
Article in English | MEDLINE | ID: mdl-36675277

ABSTRACT

The pathogenesis of non-alcoholic fatty liver disease (NAFLD), the most prevalent chronic liver disease, is associated with zinc deficiency. Previous studies show zinc supplementation improves steatosis and glucose metabolism, but its therapeutic effects in patients with established NAFLD remain unclear. We developed an in vivo model to characterize the effects of zinc supplementation on high-fat diet (HFD) induced NAFLD and hypothesized that the established NAFLD would be attenuated by zinc supplementation. Male C57BL/6J mice were fed a control diet or HFD for 12 weeks. Mice were then further grouped into normal and zinc-supplemented diets for 8 additional weeks. Body composition and glucose tolerance were determined before and after zinc supplementation. At euthanasia, plasma and liver tissue were collected for characterization and downstream analysis. As expected, 12 weeks of HFD resulted in reduced glucose clearance and altered body composition. Eight weeks of subsequent zinc supplementation did not alter glucose handling, plasma transaminases, steatosis, or hepatic gene expression. Results from our model suggest 8-week zinc supplementation cannot reverse established NAFLD. The HFD may have caused NAFLD disease progression beyond rescue by an 8-week period of zinc supplementation. Future studies will address these limitations and provide insights into zinc as a therapeutic agent for established NAFLD.


Subject(s)
Non-alcoholic Fatty Liver Disease , Male , Mice , Animals , Non-alcoholic Fatty Liver Disease/drug therapy , Non-alcoholic Fatty Liver Disease/etiology , Non-alcoholic Fatty Liver Disease/metabolism , Diet, High-Fat/adverse effects , Zinc/metabolism , Mice, Inbred C57BL , Liver/metabolism , Dietary Supplements , Glucose/metabolism , Disease Models, Animal
5.
Life Sci ; 315: 121385, 2023 Feb 15.
Article in English | MEDLINE | ID: mdl-36634865

ABSTRACT

Cadmium is a hazardous metal with multiple organ toxicity that causes great harm to human health. Cadmium enters the human body through occupational exposure, diet, drinking water, breathing, and smoking. Cadmium accumulation in the human body is associated with increased risk of developing obesity, cardiovascular disease, diabetes, and metabolic syndrome (MetS). Cadmium uptake is enhanced during pregnancy and can cross the placenta affecting placental development and function. Subsequently, cadmium can pass to fetus, gathering in multiple organs such as the liver and pancreas. Early-life cadmium exposure can induce hepatic oxidative stress and pancreatic ß-cell dysfunction, resulting in insulin resistance and glucose metabolic dyshomeostasis in the offspring. Prenatal exposure to cadmium is also associated with increasing epigenetic effects on the offspring's multi-organ functions. However, whether and how maternal exposure to low-dose cadmium impacts the risks of developing type 2 diabetes (T2D) in the young and/or adult offspring remains unclear. This review collected available data to address the current evidence for the potential role of cadmium exposure, leading to insulin resistance and the development of T2D in offspring. However, this review reveals that underlying mechanisms linking prenatal cadmium exposure during pregnancy with T2D in offspring remain to be adequately investigated.


Subject(s)
Diabetes Mellitus, Type 2 , Insulin Resistance , Metabolic Syndrome , Prenatal Exposure Delayed Effects , Adult , Pregnancy , Female , Humans , Metabolic Syndrome/chemically induced , Metabolic Syndrome/complications , Maternal Exposure , Cadmium/toxicity , Diabetes Mellitus, Type 2/chemically induced , Diabetes Mellitus, Type 2/complications , Placenta/metabolism , Prenatal Exposure Delayed Effects/metabolism
6.
Alcohol Clin Exp Res (Hoboken) ; 47(1): 60-75, 2023 01.
Article in English | MEDLINE | ID: mdl-36377258

ABSTRACT

BACKGROUND: The prevalence of alcohol-associated liver disease (ALD), a subtype of fatty liver disease (FLD), continues to rise. ALD is a major cause of preventable death. Polychlorinated biphenyl (PCB) 126 is an environmentally relevant, dioxin-like pollutant whose negative metabolic effects have been well documented. In human and animal studies, PCB has been associated with the severity of nonalcoholic fatty liver disease (NAFLD). However, few studies have investigated whether exposures to environmental toxicants can worsen ALD. Thus, the objective of the current study was to develop an alcohol-plus-toxicant model to study how an environmental pollutant, PCB 126, impacts rodent ALD pathology. METHODS: Briefly, male C57BL/6J mice were exposed to 0.2 mg/kg PCB 126 or corn oil vehicle four days prior to ethanol feeding using the chronic-binge (10-plus-one) model. RESULTS: Concentrations of macromolecules, including hepatic lipids, carbohydrates, and protein (albumin) were impacted. Exposure to PCB 126 exacerbated hepatic steatosis and hepatomegaly in mice exposed to the chemical and fed an ethanol diet. Gene expression and the analysis of blood chemistry showed a potential net increase and retention of hepatic lipids and reductions in lipid oxidation and clearance capabilities. Depletion of glycogen and glucose was evident, which contributes to disease progression by generating systemic malnutrition. Granulocytic immune infiltrates were present but driven solely by ethanol feeding. Hepatic albumin gene expression and plasma levels were decreased by ~50% indicating a potential compromise of liver function. Finally, gene expression analyses indicated that the aryl hydrocarbon receptor and constitutive androstane receptor were activated by PCB 126 and ethanol, respectively. CONCLUSIONS: Various environmental toxicants are known to modify or enhance FLD in high-fat diet models. Findings from the present study suggest that they interact with other lifestyle factors such as alcohol consumption to reprogram intermediary metabolism resulting in exacerbated ethanol-associated systemic malnutrition in ALD.


Subject(s)
Environmental Pollutants , Liver Diseases, Alcoholic , Malnutrition , Non-alcoholic Fatty Liver Disease , Polychlorinated Biphenyls , Humans , Male , Mice , Animals , Polychlorinated Biphenyls/metabolism , Polychlorinated Biphenyls/pharmacology , Environmental Pollutants/metabolism , Environmental Pollutants/pharmacology , Rodentia , Mice, Inbred C57BL , Liver/metabolism , Non-alcoholic Fatty Liver Disease/metabolism , Liver Diseases, Alcoholic/metabolism , Diet, High-Fat , Ethanol/pharmacology , Lipids/pharmacology , Malnutrition/metabolism , Malnutrition/pathology
7.
Toxicol Pathol ; 50(8): 930-941, 2022 12.
Article in English | MEDLINE | ID: mdl-36377245

ABSTRACT

This article describes the Society of Toxicologic Pathology's (STP) five recommended ("best") practices for appropriate use of informed (non-blinded) versus masked (blinded) microscopic evaluation in animal toxicity studies intended for regulatory review. (1) Informed microscopic evaluation is the default approach for animal toxicity studies. (2) Masked microscopic evaluation has merit for confirming preliminary diagnoses for target organs and/or defining thresholds ("no observed adverse effect level" and similar values) identified during an initial informed evaluation, addressing focused hypotheses, or satisfying guidance or requests from regulatory agencies. (3) If used as the approach for an animal toxicity study to investigate a specific research question, masking of the initial microscopic evaluation should be limited to withholding only information about the group (control or test article-treated) and dose equivalents. (4) The decision regarding whether or not to perform a masked microscopic evaluation is best made by a toxicologic pathologist with relevant experience. (5) Pathology peer review, performed to verify the microscopic diagnoses and interpretations by the study pathologist, should use an informed evaluation approach. The STP maintains that implementing these five best practices has and will continue to consistently deliver robust microscopic data with high sensitivity for animal toxicity studies intended for regulatory review. Consequently, when conducting animal toxicity studies, the advantages of informed microscopic evaluation for maximizing sensitivity outweigh the perceived advantages of minimizing bias through masked microscopic examination.


Subject(s)
Pathologists , Peer Review , Animals , Humans , Microscopy , No-Observed-Adverse-Effect Level
9.
Toxicol Appl Pharmacol ; 457: 116294, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36283442

ABSTRACT

Hexavalent chromium [Cr(VI)] is a well-known and widespread environmental contaminant associated with a variety of adverse health effects, in particular lung cancer. The primary route of exposure in humans is through inhalation. Particulate forms of Cr(VI) are the most potent but in vivo studies are difficult. Intratracheal instillation requires highly trained surgical procedures which also limits the number of repeated exposures possible and thus requires high doses. Inhalation studies can deliver lower more chronic doses but are expensive and generate dangerous aerosols. We evaluated an oropharyngeal aspiration exposure route for zinc chromate particles in Wistar rats. Animals were treated once per week for 90 days. We found chromium accumulated in the lungs, blood, and reproductive tissues of all treated animals. Additionally, we found inflammatory indicators in the lung were elevated and circulating lymphocytes had increased chromosomal damage. These results show oropharyngeal aspiration provides a practicable exposure route for chronic and sub-chronic exposures of Cr(VI) particles.

10.
Science ; 376(6591)2022 04 22.
Article in English | MEDLINE | ID: mdl-35949260

ABSTRACT

Whole-genome sequencing (WGS) permits comprehensive cancer genome analyses, revealing mutational signatures, imprints of DNA damage and repair processes that have arisen in each patient's cancer. We performed mutational signature analyses on 12,222 WGS tumor-normal matched pairs, from patients recruited via the UK National Health Service. We contrasted our results to two independent cancer WGS datasets, the International Cancer Genome Consortium (ICGC) and Hartwig Foundation, involving 18,640 WGS cancers in total. Our analyses add 40 single and 18 double substitution signatures to the current mutational signature tally. Critically, we show for each organ, that cancers have a limited number of 'common' signatures and a long tail of 'rare' signatures. We provide a practical solution for utilizing this concept of common versus rare signatures in future analyses.


Subject(s)
Neoplasms , Base Sequence , Cohort Studies , DNA Mutational Analysis/methods , Humans , Mutation , Neoplasms/genetics , Population/genetics , United Kingdom
12.
Ecotoxicol Environ Saf ; 234: 113373, 2022 Apr 01.
Article in English | MEDLINE | ID: mdl-35272187

ABSTRACT

As an environmental pollutant, cadmium (Cd) has been widely reported to induce male infertility due to its gonadotoxicity. However, the specific mechanism of Cd-induced testicular damage remains unclear. We investigated whether Cd causes testicular injury through ferroptosis. Male C57BL/6 J mice were exposed to 0, 0.5, or 5 ppm Cd via drinking water, starting in utero, and continuing through 24 weeks post-weaning. The results showed that Cd accumulated in the testes in a dose-dependent manner. Cd exposure at a concentration of 5 ppm, but not 0.5 ppm, caused a mass loss and detachment of germ cells, as well as a decreased meiotic index and testis weight. Exposure to 5 ppm Cd caused iron accumulation, increased levels of malondialdehyde (MDA) and nitro tyrosine (3-NT), and decreased expression of Nrf2, HO-1 and SOD2. We also found that exposure to 5 ppm Cd significantly decreased the expression of SLC7A11, a marker of ferroptosis in mice, along with the expression of SLC40A1 mRNA and ferritin heavy chain (FTH) protein, whereas there was no obvious change in the mRNA expression of Tfrc, ZIP8, ZIP14, and NCOA4. These findings indicate that 5 ppm Cd exposure increased testicular ferroptosis, which may be attributed to the reduction of stored iron export.

13.
Eur J Clin Nutr ; 76(10): 1380-1386, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35352014

ABSTRACT

BACKGROUND/OBJECTIVES: To compare the effects of supplemental inorganic nitrate (NO3) on microvascular endothelial function and blood pressure in younger vs. older participants. SUBJECTS/METHODS: 25 individuals participated in a double-blind, randomised, placebo-controlled crossover pilot study. Participants were stratified by age (18-35 and ≥55 years) and consumed a single dose beetroot juice (providing 6.4 mmol NO3) or NO3-depleted beetroot juice. Blood pressure, microvascular function (via Laser Doppler Flowmetry; LDF) and urinary NO3 were assessed, and the effects of NO3 supplementation on cardiovascular parameters were compared between participants and conditions using mixed-design ANOVA. RESULTS: Treatments and methods were well tolerated, and no adverse events were reported. Urinary NO3 increased 3 h following ingestion in both groups, (P = 0.02). Levels remained elevated at 24 h post consumption in younger participants only (P = 0.02). Beetroot juice had no effect on blood pressure in either group nor on microcirculatory endothelial function. CONCLUSIONS: Beetroot juice had no effect on blood pressure or microvascular endothelial function in young and older individuals. Dosage and timing regimens for supplemental beetroot juice should be avenues for further inquiry.


Subject(s)
Beta vulgaris , Nitrates , Antioxidants/pharmacology , Blood Pressure , Cross-Over Studies , Dietary Supplements , Double-Blind Method , Fruit and Vegetable Juices , Humans , Microcirculation , Middle Aged , Nitrates/pharmacology , Nitrites/pharmacology , Pilot Projects
14.
Chem Biol Interact ; 353: 109797, 2022 Feb 01.
Article in English | MEDLINE | ID: mdl-34998821

ABSTRACT

Although several studies have reported testicular impairments caused by cadmium (Cd) or obesity alone, the combined effect of Cd and obesity on the testes and its underlying mechanism remains unclear. We examined the combined effect of whole-life exposure to low-dose Cd started at preconception and post-weaning high-fat diet (HFD) on the testes of offspring mice. At weaning, male offspring parented with and without exposure to low-dose Cd were continued on the same drinking water regimen as their parents and fed with either a normal diet (ND) or HFD for 10 or 24 weeks. Whole-life exposure to Cd resulted in its accumulation in testes, and HFD induced obesity and lipid metabolism disorder. Exposure to Cd or HFD alone significantly decreased Johnsen scores, disrupted testicular structure, and increased germ cell apoptosis at both 10 and 24 weeks. However, co-exposure to Cd and HFD did not induce the toxic effects that were induced by either alone, as revealed by preserved testicular structure and spermatogenesis, lack of significant apoptosis, and increased cell proliferation. Mechanistically, the combined effects of low-dose Cd and HFD consumption were associated with the activation of the JAK/STAT pathway. These findings suggest that co-exposure to low-dose Cd and HFD did not cause Cd- or HFD-induced testicular injury, probably because of the activation of the JAK/STAT pathway to prevent germ cell apoptosis.


Subject(s)
Cadmium/toxicity , Diet, High-Fat , Spermatogenesis/drug effects , Testis/physiology , Animals , Animals, Newborn , Apoptosis/drug effects , Cadmium/analysis , Female , Germ Cells/cytology , Germ Cells/metabolism , Janus Kinases/metabolism , Lipid Metabolism/drug effects , Male , Mice , Mice, Inbred C57BL , Models, Animal , Oxidative Stress/drug effects , STAT Transcription Factors/metabolism , Signal Transduction/drug effects , Testis/anatomy & histology , Testis/chemistry
15.
Toxicol Appl Pharmacol ; 436: 115855, 2022 02 01.
Article in English | MEDLINE | ID: mdl-34990729

ABSTRACT

Nonalcoholic fatty liver disease (NAFLD) is a major global public health concern affecting more than 25% of the world's population. Although obesity and diabetes are major risk factors for NAFLD, they cannot account for all cases, indicating the importance of other factors such as environmental exposures. Cadmium (Cd) exposure is implicated in the development of NAFLD; however, the influence of early life, in utero Cd exposure on the development of diet-induced NAFLD is poorly understood. Therefore, we developed an in vivo, multiple-hit model to study the effect of whole-life, low dose Cd exposure on high fat diet (HFD)-induced NAFLD. Adult male and female C57BL/6 J mice fed normal diets (ND) were exposed to 0, 0.5 or 5 ppm Cd-containing drinking water for 14 weeks before breeding. At weaning, offspring were fed ND or HFD and continued on the same drinking water regimen as their parents for 24 weeks. Cd exposure at different concentrations differentially altered HFD-associated adverse health effects, including liver injury. HFD-induced increased body weight, decreased glucose tolerance. Liver injury and lipid deposition were exacerbated by 5 ppm Cd exposure but attenuated by 0.5 ppm Cd exposure. Further, HFD blunted the response of metallothionein, a major Cd detoxification protein, in mice exposed to 5 ppm Cd but enhanced the response in mice exposed to 0.5 ppm Cd, suggesting a possible mechanism for Cd alteration of HFD-induced NAFLD. These results confirm the multi-hit nature of NAFLD and show whole life, low dose Cd exposure alters HFD-induced NAFLD with outcomes dependent on Cd concentration.


Subject(s)
Cadmium/adverse effects , Liver/drug effects , Non-alcoholic Fatty Liver Disease/chemically induced , Animals , Diet, High-Fat/methods , Disease Models, Animal , Female , Lipid Metabolism/drug effects , Male , Mice , Mice, Inbred C57BL , Oxidative Stress/drug effects , Signal Transduction/drug effects
16.
Mol Cancer Ther ; 21(4): 594-606, 2022 04 01.
Article in English | MEDLINE | ID: mdl-35086954

ABSTRACT

Multivalent second-generation TRAIL-R2 agonists are currently in late preclinical development and early clinical trials. Herein, we use a representative second-generation agent, MEDI3039, to address two major clinical challenges facing these agents: lack of predictive biomarkers to enable patient selection and emergence of resistance. Genome-wide CRISPR knockout screens were notable for the lack of resistance mechanisms beyond the canonical TRAIL-R2 pathway (caspase-8, FADD, BID) as well as p53 and BAX in TP53 wild-type models, whereas a CRISPR activatory screen identified cell death inhibitors MCL-1 and BCL-XL as mechanisms to suppress MEDI3039-induced cell death. High-throughput drug screening failed to identify genomic alterations associated with response to MEDI3039; however, transcriptomics analysis revealed striking association between MEDI3039 sensitivity and expression of core components of the extrinsic apoptotic pathway, most notably its main apoptotic effector caspase-8 in solid tumor cell lines. Further analyses of colorectal cell lines and patient-derived xenografts identified caspase-8 expression ratio to its endogenous regulator FLIP(L) as predictive of sensitivity to MEDI3039 in several major solid tumor types and a further subset indicated by caspase-8:MCL-1 ratio. Subsequent MEDI3039 combination screening of TRAIL-R2, caspase-8, FADD, and BID knockout models with 60 compounds with varying mechanisms of action identified two inhibitor of apoptosis proteins (IAP) that exhibited strong synergy with MEDI3039 that could reverse resistance only in BID-deleted models. In summary, we identify the ratios of caspase-8:FLIP(L) and caspase-8:MCL-1 as potential predictive biomarkers for second-generation TRAIL-R2 agonists and loss of key effectors such as FADD and caspase-8 as likely drivers of clinical resistance in solid tumors.


Subject(s)
Proto-Oncogene Proteins c-bcl-2 , TNF-Related Apoptosis-Inducing Ligand , Apoptosis , CASP8 and FADD-Like Apoptosis Regulating Protein/genetics , CASP8 and FADD-Like Apoptosis Regulating Protein/metabolism , Caspase 8/genetics , Cell Line, Tumor , Genomics , Humans , Proto-Oncogene Proteins c-bcl-2/metabolism , TNF-Related Apoptosis-Inducing Ligand/metabolism , TNF-Related Apoptosis-Inducing Ligand/pharmacology
17.
Environ Int ; 158: 106877, 2022 01.
Article in English | MEDLINE | ID: mdl-34547640

ABSTRACT

Hexavalent chromium [Cr(VI)] is a global environmental pollutant that increases risk for several types of cancers and is increasingly being recognized as a neurotoxicant. Traditionally, the brain has been viewed as a largely post-mitotic organ due to its specialized composition of neurons, and consequently, clastogenic effects were not considered in neurotoxicology. Today, we understand the brain is composed of at least eight distinct cell types - most of which continue mitotic activity throughout lifespan. We have learned these dividing cells play essential roles in brain and body health. This review focuses on Cr(VI), a potent clastogen and known human carcinogen, as a potentially neurotoxic agent targeting mitotic cells of the brain. Despite its well-established role as a human carcinogen, Cr(VI) neurotoxicity studies have failed to find a significant link to brain cancers. In the few studies that did find a link, Cr(VI) was identified as a risk for gliomas. Instead, in the human brain, Cr(VI) appears to have more subtle deleterious effects that can impair childhood learning and attention development, olfactory function, social memory, and may contribute to motor neuron diseases. Studies of Cr(VI) neurotoxicity with animal and cell culture models have demonstrated elevated markers of oxidative damage and redox stress, with widespread neurodegeneration. One study showed mice exposed to Cr(VI)-laden tannery effluent exhibited longer periods of aggressive behavior toward an "intruder" mouse and took longer to recognize mice previously encountered, recapitulating the social memory deficits observed in humans. Here we conducted a critical review of the available literature on Cr(VI) neurotoxicity and synthesize the collective observations to thoroughly evaluate Cr(VI) neurotoxicity - much remains to be understood and recognized.


Subject(s)
Chromium , Environmental Pollutants , Animals , Chromium/toxicity , DNA Damage , Environmental Pollutants/toxicity , Mice , Oxidative Stress
18.
Sci Total Environ ; 818: 151848, 2022 Apr 20.
Article in English | MEDLINE | ID: mdl-34822883

ABSTRACT

An increasing body of evidence implicates high levels of selenium intake in the development of diabetes, although prospective studies remain sparse. We conducted a nested case-control study of 622 diabetes incident cases and 622-age, sex, and follow-up time-matched controls in the prospective Jinchang cohort of 48,001 participants with a median of 5.8 years of follow-up. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure all 622 case-control pairs' baseline serum levels of selenium (Se), which were then categorized into quartiles based on the frequency distribution among the controls. Multivariable adjusted conditional logistic regression and restricted cubic splines (RCS) models were applied to evaluate independent odds ratios (OR) as estimates for relative risks (RR) of diabetes according to quartiles (Q) of selenium levels. Compared to the lowest quartile (Q1 as reference), significantly greater diabetes risks (with 95% confidence interval) were observed in Q3 (OR = 1.62, 1.17-2.35) and Q4 (OR = 1.79, 1.21-2.64). Sub-analyses showed these increased risks of diabetes by serum levels of Se. appeared to differ by sex, age, BMI status, history of hypertension, and dyslipidemia. Further, application of RSC models showed that serum Se levels between 95 and 120 µg/L were significantly and positively associated with diabetes risk whereas no apparent relation exists when Se levels were under 95 µg/L in this cohort population.


Subject(s)
Diabetes Mellitus , Selenium , Case-Control Studies , Child, Preschool , Diabetes Mellitus/epidemiology , Humans , Odds Ratio , Prospective Studies , Risk Factors
19.
Sci Total Environ ; 809: 152176, 2022 Feb 25.
Article in English | MEDLINE | ID: mdl-34875320

ABSTRACT

We previously showed the development of cardiac remodeling (hypertrophy or fibrosis) in mice with either post-weaning high-fat diet (HFD, 60% kcal fat) feeding or exposure to chronic low-dose cadmium. Here, we determined whether whole-life exposure to environmentally relevant, low-dose cadmium affects the susceptibility of offspring to post-weaning HFD-induced cardiac pathologies and function. Besides, we also determined whether these effects are sex-dependent. Male and female mice were exposed to cadmium-containing (0, 0.5, or 5 parts per million [ppm]) drinking water before breeding; the pregnant mice and dams with offspring continually drank the same cadmium-containing water. After weaning, the offspring were continued on the same regime as their parents and fed either a HFD or normal fat diet for 24 weeks. Cardiac function was examined with echocardiography. Cardiac tissues were used for the histopathological and biochemical (gene and protein expression by real-time PCR and Western blotting) assays. Results showed a dose-dependent cadmium accumulation in the hearts of male and female mice along with decreased cardiac zinc and copper levels only in female offspring. Exposure to 5 ppm, but not 0.5 ppm, cadmium significantly enhanced HFD cardiac effects only in female mice, shown by worsened cardiac systolic and diastolic dysfunction (ejection fraction, mitral E-to-annular e' ratio), increased fibrosis (collagen, fibronectin, collagen1A1), hypertrophy (cardiomyocyte size, atrial natriuretic peptide, ß-myosin heavy chain), and inflammation (intercellular adhesion molecule-1, tumor necrosis factor-α, plasminogen activator inhibitor type 1), compared to the HFD group. These synergistic effects were associated with activation of the p38 mitogen-activated protein kinases (MAPK) signaling pathway and increased oxidative stress, shown by 3-nitrotyrosine and malondialdehyde, along with decreased metallothionein expression. These results suggest that whole-life 5 ppm cadmium exposure significantly increases the susceptibility of female offspring to HFD-induced cardiac remodeling and dysfunction. The underlying mechanism and potential intervention will be further explored in the future.


Subject(s)
Cadmium , Diet, High-Fat , Animals , Cadmium/metabolism , Cadmium/toxicity , Diet, High-Fat/adverse effects , Female , Male , Mice , Mice, Inbred C57BL , Myocytes, Cardiac , Oxidative Stress , Pregnancy , Sex Characteristics
20.
Oxid Med Cell Longev ; 2021: 1427787, 2021.
Article in English | MEDLINE | ID: mdl-34876963

ABSTRACT

Maternal exposure to cadmium causes obesity and metabolic changes in the offspring, including nonalcoholic fatty liver disease-like pathology. However, whether maternal cadmium exposure accelerates liver cancer in the offspring is unknown. This study investigated the impact of early-life exposure to cadmium on the incidence and potential mechanisms of hepatocellular carcinoma (HCC) in offspring subjected to postweaning HCC induction. HCC in C57BL/6J mice was induced by diethylnitrosamine (DEN) injection at weaning, followed by a long-term high-fat choline-deficient (HFCD) diet. Before weaning, liver cadmium levels were significantly higher in mice with early-life cadmium exposure than in those without cadmium exposure. However, by 26 and 29 weeks of age, hepatic cadmium fell to control levels, while a significant decrease was observed in copper and iron in the liver. Both male and female cadmium-exposed mice showed increased body weight compared to non-cadmium-treated mice. For females, early-life cadmium exposure also worsened insulin intolerance but did not significantly promote DEN/HFCD diet-induced liver tumors. In contrast, in male mice, early-life cadmium exposure enhanced liver cancer induction by DEN/HFCD with high incidence and larger liver tumors. The liver peritumor tissue of early-life cadmium-exposed mice exhibited greater inflammation and disruption of fatty acid metabolism, accompanied by higher malondialdehyde and lower esterified triglyceride levels compared to mice without cadmium exposure. These findings suggest that early-life exposure to low-dose cadmium accelerates liver cancer development induced by a DEN/HFCD in male mice, probably due to chronic lipotoxicity and inflammation caused by increased uptake but decreased consumption of fatty acids.


Subject(s)
Cadmium/toxicity , Diet, High-Fat , Diethylnitrosamine/pharmacology , Liver Neoplasms/pathology , Animals , Animals, Newborn , Choline/metabolism , Diet, High-Fat/veterinary , Disease Models, Animal , Fatty Acids/metabolism , Female , Liver/pathology , Liver Neoplasms/chemically induced , Male , Malondialdehyde/metabolism , Mice , Mice, Inbred C57BL , Triglycerides/metabolism
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