Lead increases lipopolysaccharide-induced liver-injury through tumor necrosis factor-alpha overexpression by monocytes/macrophages: role of protein kinase C and P42/44 mitogen-activated protein kinase

Low Dose of Nickel and Benzo [a] Anthracene in Rat-Diet, Induce Apoptosis, Fibrosis, and Initiate Carcinogenesis in Liver via NF-Ƙβ Pathway

Environmental contaminants such as polycyclic aromatic hydrocarbon (PAH) and heavy metals are major contaminants of food such as fish thus serving as source of exposure to human. This study was designed to evaluate the carcinogenic risk and other risks associated with long-term consumption of environmentally relevant dose of nickel and benzo [a] anthracene in rats. Thirty-six (36) male rats weighing between 80 and 100 g were assigned into 6 groups of 6 animals each; normal, nickel-, and benzo [a] anthracene-exposed groups for 12 and 24 weeks, respectively. Micronucleus and comet analyses were done in the blood, liver, and bone marrow. Liver function, redox, and inflammatory markers (AST, ALT, GGT, SOD, GSH, MDA, protein carbonyl, protein thiol, total protein, IL-10, 1L-1β, TNF-α, TGF-β NF-Ƙβ, and 8-oxodeoxyguansine) were analysed by standard methods. Immuno-histochemical quantification of Bax, Bcl2, and Erk 1/2 as well as mRNA expression of cyclin D1 was done in liver. From the results, weight gain was observed in varying degrees throughout the exposure period. The polychromatic erythrocytes/normochromatic erythrocytes ratio > 0.2 indicates no cytotoxic effects on the bone marrow. Percentage-MnPCE in blood significantly (p < 0.05) increased throughout exposure duration. Percentage tail DNA in blood was significantly (< 0.05) increased at weeks 20 and 24 in the exposed groups and in liver at weeks 12 (16.22 ± 0.47) and 24 (17.00 ± 0.36) of nickel-exposed rats. The aspartate amino transferase (AST):alanine amino transferase (ALT) ratio indicated fatty liver disease in the benzo [a] anthracene (0.90) and acute liver injury in the nickel (> 10 times greater than the upper limits of the reference group) exposed groups during the first 12 weeks. Observation from the histological and cytological data of the liver revealed the presence of inflammation, fibrosis, and high nuclear/cytoplasmic ratio, respectively, in the nickel and benzo [a] anthracene groups. Only benzo [a] anthracene induced liver oxidative stress with significant (p < 0.05) decrease in SOD (0.64 ± 0.02) activity and increase in protein carbonyl (7.60 ± 0.80 × 10-5) and MDA (57.10 ± 6.64) concentration after 24 weeks. Benzo [a] anthracene up-regulated the cyclin D1 expression and significantly (p < 0.05) increased the levels of the cytokines. Nickel and benzo [a] anthracene significantly (p < 0.05) increased the Bax (183.45 ± 6.50 and 199.76 ± 10.04) and Erk 1/2 (108.25 ± 6.41 and 136.74 ± 4.22) levels when compared with the control (37.43 ± 22.22 and 60.37 ± 17.86), respectively. Overall result showed that the toxic effects of nickel and benzo [a] anthracene might involve fibrosis, cirrhosis, apoptosis, and inflammation of the liver. As clearly demonstrated in this study, benzo [a] anthracene after the 24 weeks of exposure stimulates carcinogenic process by suppressing the liver antioxidant capacity, altering apoptotic, cell proliferation, and differentiation pathways.

Influence of lead-induced toxicity on the inflammatory cytokines

Lead (Pb2+) is a hazardous heavy metal that is pervasive in the human environment as a result of anthropogenic activity, and poses serious health risks, particularly in children. Due to its innumerable unique physical and chemical properties, it has various applications; therefore, it has become a common environmental pollutant. Lead may cause oxidative stress, and accumulating evidence indicates that oxidative stress influences the pathophysiology of lead poisoning, also called plumbism. The immune system is continually exposed to various environmental pathogens and xenobiotics, including heavy metals such as lead, and appears to be one of the most vulnerable targets. After being exposed to lead, cells are subjected to oxidative stress as a result of reactive oxygen species (ROS) production. When the generation and consumption of ROS are out of equilibrium, various cell structures, particularly phospholipids are disrupted leading to lipid peroxidation. Various inflammatory signalling pathways are activated as a consequence, along with reduced disease resistance, inflammation, autoimmunity, sensitization and disruption of the cell-mediated and humoral immune systems. Lead negatively affects the metabolism of cytokines, including the interleukins IL-2, IL-1b, IL-6, IL-4, IL-8, tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN), as well as the expression and functioning of inflammatory enzymes such as cyclooxygenases. However, the cause of toxicity depends on the kind of lead, dosage, route of entry, exposure period, age, host and genetic predisposition.

Oryza sativa L. Indica Seed Coat Ameliorated Concanavalin A-Induced Acute Hepatitis in Mice via MDM2/p53 and PKCα/MAPK1 Signaling Pathways

Acute hepatitis (AH) is a common liver disease with an increasing number of patients each year, requiring the development of new treatments. Hence, our work aimed to evaluate the therapeutic effect of Oryza sativa L. indica (purple rice) seed coat on concanavalin A (ConA)-induced AH and further reveal its potential mechanisms. Purple rice seed coat extract (PRE) was extracted with hydrochloric acid ethanol and analyzed through a widely targeted components method. We evaluated the effects of PRE on AH through histopathological examination, liver function, gut microbiota composition, and the intestinal barrier. The potential targets of PRE on AH were predicted by bioinformatics. Western blotting, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay (TUNEL) staining, and corresponding kits were used to investigate PRE effects on predicting targets and associated signaling pathways in AH mice. In AH model mice, PRE treatment increased transformed mouse 3T3 cell double minute 2 (MDM2) expression to inhibit apoptosis; it also markedly downregulated protein kinase C alpha (PKCα), prostaglandin-endoperoxide synthase 1 (PTGS1), and mitogen-activated protein kinase 1 (MAPK1) activity to alleviate inflammation. Thus, PRE treatment also recovered the intestinal barrier, decreased the lipopolysaccharide (LPS) levels of plasma and the liver, enhanced liver function, and improved the composition of intestinal microbiota. In general, PRE targeting MDM2, PKCα, MAPK1, and PTGS1 ameliorated ConA-induced AH by attenuating inflammation and apoptosis, restoring the intestinal barrier, enhancing the liver function, and improving the gut microbiota, which revealed that the purple rice seed coat might hold possibilities as a therapeutic option for AH.

Potential diagnostic biomarkers for lead-induced hepatotoxicity and the role of synthetic chelators and bioactive compounds

Lead (Pb2+) poisoning is a public health concern of global dimensions. Although several public health guidelines and workplace safety policies are existing and enforced, lead toxicity cases are drastically increasing. Lead exposure leads to numerous harmful consequences and causes adverse effects on different body organs and systems, mainly via the generation of reactive oxygen species, leading to augmented oxidative stress, competing with metal ions, and binding with the sulfhydryl groups. In several instances, lead poisoning cases remain undiagnosed and untreated or receive only symptomatic treatment. Estimation of blood lead levels reflects only a recent exposure, however, which does not reveal the total body burden. This review summarizes the effects of lead with special reference to hepatotoxicity and some of the potential diagnostic biomarkers. Furthermore, it also focuses on synthetic chelators used in the treatment of lead poisoning and the advantage of using bioactive compounds with an emphasis on the ameliorative effect of garlic.

Molecular mechanism of heavy metals (Lead, Chromium, Arsenic, Mercury, Nickel and Cadmium) - induced hepatotoxicity - A review

Heavy metals pose a serious threat if they go beyond permissible limits in our bodies. Much heavy metal's viz. Lead, Chromium, Arsenic, Mercury, Nickel, and Cadmium pose a serious threat when they go beyond permissible limits and cause hepatotoxicity. They cause the generation of ROS which in turn causes numerous injuries and undesirable changes in the liver. Epidemiological studies have shown an increase in the levels of such heavy metals in the environment posing a serious threat to human health. Epigenetic alterations have been seen in the event of exposure to such heavy metals. Apoptosis, caspase activation as well as ultrastructural changes in the hepatocytes have also been seen due to heavy metals. Inflammation involving TNF-alpha, pro-inflammatory cytokines, MAPK, ERK pathways have been seen in the event of heavy metal hepatotoxicity. All these have shown that these heavy metals pose a serious threat to human health in particular and the environment as a whole.

Plant-Derived Food Grade Substances (PDFGS) Active Against Respiratory Viruses: A Systematic Review of Non-clinical Studies

Human diet comprises several classes of phytochemicals some of which are potentially active against human pathogenic viruses. This study examined available evidence that identifies existing food plants or constituents of edible foods that have been reported to inhibit viral pathogenesis of the human respiratory tract. SCOPUS and PUBMED databases were searched with keywords designed to retrieve articles that investigated the effect of plant-derived food grade substances (PDFGS) on the activities of human pathogenic viruses. Eligible studies for this review were those done on viruses that infect the human respiratory tract. Forty six (46) studies met the specified inclusion criteria from the initial 5,734 hits. The selected studies investigated the effects of different PDFGS on the infectivity, proliferation and cytotoxicity of different respiratory viruses including influenza A virus (IAV), influenza B virus (IBV), Respiratory syncytial virus (RSV), human parainfluenza virus (hPIV), Human coronavirus NL63 (HCoV-NL63), and rhinovirus (RV) in cell lines and mouse models. This review reveals that PDFGS inhibits different stages of the pathological pathways of respiratory viruses including cell entry, replication, viral release and viral-induced dysregulation of cellular homeostasis and functions. These alterations eventually lead to the reduction of virus titer, viral-induced cellular damages and improved survival of host cells. Major food constituents active against respiratory viruses include flavonoids, phenolic acids, tannins, lectins, vitamin D, curcumin, and plant glycosides such as glycyrrhizin, acteoside, geniposide, and iridoid glycosides. Herbal teas such as guava tea, green and black tea, adlay tea, cistanche tea, kuding tea, licorice extracts, and edible bird nest extracts were also effective against respiratory viruses in vitro. The authors of this review recommend an increased consumption of foods rich in these PDFGS including legumes, fruits (e.g berries, citrus), tea, fatty fish and curcumin amongst human populations with high prevalence of respiratory viral infections in order to prevent, manage and/or reduce the severity of respiratory virus infections.

The Influence of Feed and Drinking Water on Terrestrial Animal Research and Study Replicability

For more than 50 years, the research community has made strides to better determine the nutrient requirements for many common laboratory animal species. This work has resulted in high-quality animal feeds that can optimize growth, maintenance, and reproduction in most species. We have a much better understanding of the role that individual nutrients play in physiological responses. Today, diet is often considered as an independent variable in experimental design, and specialized diet formulations for experimental purposes are widely used. In contrast, drinking water provided to laboratory animals has rarely been a consideration in experimental design except in studies of specific water-borne microbial or chemical contaminants. As we advance in the precision of scientific measurements, we are constantly discovering previously unrecognized sources of experimental variability. This is the nature of science. However, science is suffering from a lack of experimental reproducibility or replicability that undermines public trust. The issue of reproducibility/replicability is especially sensitive when laboratory animals are involved since we have the ethical responsibility to assure that laboratory animals are used wisely. One way to reduce problems with reproducibility/replicability is to have a strong understanding of potential sources of inherent variability in the system under study and to provide "…a clear, specific, and complete description of how the reported results were reached [1]." A primary intent of this review is to provide the reader with a high-level overview of some basic elements of laboratory animal nutrition, methods used in the manufacturing of feeds, sources of drinking water, and general methods of water purification. The goal is to provide background on contemporary issues regarding how diet and drinking water might serve as a source of extrinsic variability that can impact animal health, study design, and experimental outcomes and provide suggestions on how to mitigate these effects.

Docosahexaenoic Acid (DHA, C22:6, ω-3) Composition of Milk and Mammary Gland Tissues of Lactating Mother Rats Is Severely Affected by Lead (Pb) Exposure

Docosahexaenoic acid (DHA, C22:6, ω-3), an ω-3 polyunsaturated fatty acid (PUFA), is critical for brain growth, development, and cognitive ability. It is consumed by offspring via milk during lactation. However, the toxic heavy metal lead (Pb) readily passes into the mammary glands of mother animals and then to offspring through milk. Here, we investigated whether DHA composition of milk and mammary gland tissues is affected by Pb exposure. Mother rats were exposed to Pb via drinking water (0.1%). The fatty acid profile and levels of reduced glutathione (GSH), lipid peroxide (LPO), and pro-inflammatory TNF-α in milk and mammary tissues were measured. Levels of DHA and antioxidant GSH decreased (P < 0.05), while LPO and TNF-α levels increased (P < 0.05) both in milk and mammary tissues. Our results suggest that toxic Pb exposure can upset the level of milk DHA, which may affect brain growth and development, and hence cognitive ability in adulthood and later life.

Leukocyte apoptosis, TNF-α concentration and oxidative damage in lead-exposed workers

Lead intoxication can generate pro-inflammatory conditions that have been proposed to be associated with cell injuries and oxidative stress. The pro-inflammatory state can participate in the pathophysiology of this toxicity to generate immune response dysfunctions, which could condition the presence of clinical manifestations and susceptibility to infections already described in lead-exposed patients. In the present work, we study workers of a battery recycler factory (n = 24) who are chronically exposed to lead and compared them with non-lead exposed workers (n = 17). Lead-exposed workers had high lead concentrations in blood (med 69.8 vs. 1.7 μg/dL), low δ-ALAD activity (med 149 vs. 1100 nmol PBG/h/mL), high lipid peroxidation (med 0.86 vs. 0.69 nmol/mL) and high erythrocytes apoptosis (med 0.81 vs. 0.50% PS externalization) in relation to non-lead exposed workers. Also, lead-exposed workers had a high incidence of signs and symptoms related to lead intoxication and a higher frequency of infections. The higher leukocyte apoptosis (med 18.3 vs. 8.2% PS externalization) and lower basal TNF-α concentration (med 0.38 vs. 0.94 pg/mL) in lead-exposed workers imply an immune response dysfunction; however, there was no difference in the TNF-α concentration when leukocytes were stimulated with lipopolysaccharide in whole blood (med 44 vs. 70 pg/mL), suggesting that lead-exposed workers might develop adaptation mechanisms to reduce basal TNF-α release through downregulation processes proposed for this cytokine.

Elevated levels of lead exposure and impact on the anti-inflammatory ability of oral sialic acids among preschool children in e-waste areas

The oral health of preschool children in an electronic waste (e-waste) area is susceptible to lead (Pb) exposure increasing the risk of dental caries and causing periodontitis and other oral diseases. The aim of the present study is to investigate the relationship between chronic exposure to Pb and oral anti-inflammatory potential of preschool children. For this analysis, 574 preschool children from 2.5 to 6 years of age were recruited between November and December 2017, in which 357 preschool children were from Guiyu (n = 357), an e-waste-contaminated town, and 217 from Haojiang Shantou. We measured the levels of child blood Pb, salivary sialic acid, serum interleukin-6 (IL-6) and serum tumor necrosis factor-α (TNF-α), and investigated the prevalence of dental caries in deciduous teeth. The medians of blood Pb levels, serum IL-6 and TNF-α were significantly higher in the Guiyu children than in Haojiang children. Concomitantly, salivary sialic acids were lower in the Guiyu children [9.58 (3.97, 18.42) mg/dL] than in Haojiang [17.57 (5.95, 24.23) mg/dL]. Additionally, the prevalence of dental caries in deciduous teeth was significantly higher in the Guiyu children than in Haojiang (62.5% vs. 53.9%). Blood Pb levels were negatively correlated with salivary sialic acids, in which IL-6 played as a mediator of the association between blood Pb levels and saliva sialic acid concentrations according to the mediation model. To our knowledge, this is the first report on the potential association between chronic Pb exposure and the anti-inflammatory ability of oral sialic acids among preschool children. These results suggest that the chronic Pb exposure can reduce salivary sialic acid levels, attenuate oral anti-inflammatory potential and increase the potential risk of dental caries in deciduous teeth among preschool children in an e-waste site.

Protective effect of Vitamin D3 against lead induced hepatotoxicity, oxidative stress, immunosuppressive and calcium homeostasis disorders in rat

Lead (Pb) is an extremely poisonous, non-essential trace element and toxicity develops in humans following frequent exposure to the heavy metal in polluted environmental and occupational settings. Pb induces hepatic damage through the depletion of the antioxidant system, enhancing cellular oxidative stress and stimulation of proinflammatory cytokines. Although the antioxidant and anti-inflammatory actions of vitamin D₃ (VD₃) are well-established, a minority of studies measured the protective actions of VD₃ against Pb toxicity. Therefore, this work studied the effects of vitamin VD₃ therapy on the fundamental molecular basis underlying hepatic injury induced by chronic Pb toxicity. Twenty-four adult male rats were distributed equally into the negative controls (NC), positive controls (PC) and VD3 groups. While both the PC and VD3 groups received Pb-acetate in drinking water (1000 mg/L) for four weeks, the latter group also received intramuscular VD3 injections (1000 IU/kg; 3 days/week) simultaneously with Pb. The liver enzymes together with the serum and hepatic tissue Pb concentrations increased markedly in the PC group compared with the NC group. Pb toxicity also drastically induced hepatocyte apoptosis/necrosis, increased the hepatic tissue concentrations of malondialdehyde and the pro-inflammatory cytokines (TGF-β, IL-4 & TNF-α) as well as reduced the anti-oxidative enzymes (GSH, GPx & CAT) and the anti-inflammatory cytokine, IL-10, compared with the NC group. Pb also significantly decreased the serum concentrations of VD3 and Ca²⁺. Additionally, the hepatic expressions of VD receptor, Cyp24a1 enzyme, L-type Ca²⁺-channel, calbindin-D_28k & -D_29k, calmodulin and calmodulin-dependent protein kinase II were significantly upregulated, whereas the VD binding protein, CYP2R1 enzyme and T-type Ca²⁺-channel were markedly inhibited at the gene and protein levels following Pb intoxication. VD3 alleviated the hepatic damage, inhibited the oxidative stress and pro-inflammatory molecules as well as upregulated the anti-oxidant and anti-inflammatory markers and restored the expression of the VD/Ca²+ regulatory molecules compared with the PC group. VD3 supplementation discloses promising protective effects against Pb-induced hepatic damage, through its anti-inflammatory and antioxidant actions as well as by modulating the hepatocyte calcium homeostatic molecules.

The remedial effect of Thymus vulgaris extract against lead toxicity-induced oxidative stress, hepatorenal damage, immunosuppression, and hematological disorders in rats

The Thymus vulgaris (T. vulgaris) has been used in foods for the flavor, aroma, and preservation and in folk medicines. The objective of the present work was to determine the antioxidant and protective effects of T. vulgaris extract against lead (Pb)-intoxicated rats. A thirty-two male Sprague-Dawley were randomly assigned into 4 equal groups and treated for six weeks as follows: group I (GP-I), served as negative control; GP-II, -III, and -IV received either Pb acetate in drinking water (500 mg/L), T. vulgaris extract (500 mg/kg/day) by oral gavage or Pb acetate with T. vulgaris extract, respectively. Blood samples were collected at the end of the study week 6 to measure the hepatic and renal biochemical markers, complete blood count alongside the serum levels of interleukin (IL)-1β, IL-6, IL-10, tumor necrosis (TNF)-α, and interferon (IFN)-γ. Additionally, liver and kidney tissue specimens were collected for histopathology as well as to measure the antioxidant-reduced glutathione (GSH), glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD) alongside the lipid peroxidation marker, malonaldehyde (MDA). The results indicated that Pb toxicity increased the serum levels of IL-1β, IL-6, and TNF-α, whereas IL-10 and IFN-γ were reduced. The results showed disturbed liver and renal functions; increased serum levels of ALT, AST, ALP, total bilirubin, creatinine, and urea; and decreased total protein, albumin, and calcium. The GSH, Gpx, and CAT levels were significantly decreased in the Pb-administrated group, while MDA was increased. However, regarding the hepatorenal markers, those animals treated with T. vulgaris alone did not induce any significant changes. Moreover, the combined treatment with T. vulgaris extract together with Pb showed significant improvement in Pb-induced toxicity in all the tested parameters compared to the negative control group. We investigated the potential protective effects of the medicinal plant T. vulgaris in vivo, since there are no publications that address the potential protective effect of this leaf extract against Pb-induced hepatorenal toxicity. Our studies concluded that the T. vulgaris extract reduces Pb overload in hepatorenal tissues, and that this has a potential immunomodulatory role, antioxidant activity, and a protective effect against Pb toxicity.

Fatty acid levels alterations in THP-1 macrophages cultured with lead (Pb)

OBJECTIVE

As cardiovascular events are one of the main causes of death in developed countries, each factor potentially increasing the risk of cardiovascular disease deserves special attention. One such factor is the potentially atherogenic effect of lead (Pb) on lipid metabolism, and is significant in view of the still considerable Pb environmental pollution and the non-degradability of Pb compounds.

METHODS

Analysis of saturated fatty acids (SFA) (caprylic acid (C8:0), decanoic acid (C10:0), lauric acid (C12:0), tridecanoic acid (C13:0), myristic acid (C14:0), pentadecanoic acid (C15:0), palmitic acid (C16:0), heptadecanoic acid (C17:0), stearic acid (C18:0), and behenic acid (C22:0)), monounsaturated fatty acid (MUFA) (palmitoleic acid (C16:1), oleic acid (18:1w9), trans-vaccenic acid (C18:1 trans11)), and polyunsaturated fatty acid (PUFA) (linoleic acid (C18:2n6), gamma-linolenic acid (C18:3n6), arachidonic acid (C20:4n6)), was conducted by gas chromatography. Analysis of stearoyl-CoA desaturase (SCD), fatty acid desaturase 1 (FADS1) and fatty acid desaturase 2 (FADS2) expression was performed using qRT-PCR. Oxidative stress intensity (malondialdehyde - MDA concentration) was measured using spectrophotometric method. Intracellular generation of reactive oxygen species (ROS) in macrophages was visualized by fluorescence microscopy and quantitatively measured by plate reader.

RESULTS

Pb caused quantitative alterations in FAs profile in macrophages; the effect was Pb-concentration dependent and selective (i.e. concerned only selected FAs). In general, the effect of Pb was biphasic, with Pb levels of 1.25 μg/dL and 2.5 μg/dL being stimulatory, and 10 μg/dL being inhibitory on concentrations of selected FAs. The most potent Pb concentration, resulting in increase in levels of 9 FAs, was 2.5 μg/dL, the Pb-level corresponding to the mean blood Pb concentrations of people living in urban areas not contaminated by Pb. Pb was found to exert similar, biphasic effect on the expression of FADS1. However, Pb decreased, in a concentration-dependent manner, the expression of SCD and FADS2. Pb significantly increased MDA and ROS concentration in macrophages.

CONCLUSION

Environmental Pb exposure might be a risk factor resulting in alterations in FAs levels, oxidative stress and increased MDA concentration in macrophages, which might lead to the formation of foam cells and to inflammatory reactions.

Cardiovascular endothelial inflammation by chronic coexposure to lead (Pb) and polycyclic aromatic hydrocarbons from preschool children in an e-waste recycling area

Lead (Pb) and polycyclic aromatic hydrocarbon (PAH) exposure is positively associated with cardiovascular disease (CVD), and the possible potential mechanism may be caused by damage to the endothelium by modulation of inflammatory processes. No comprehensive research shows co-exposure of Pb and PAH on cardiovascular endothelial inflammation in electronic waste (e-waste) exposed populations. Given this, the aim of this study is to provide evidence for a relationship between Pb and PAH co-exposure and cardiovascular endothelial inflammation, in an e-waste-exposed population, to delineate the link between a potential mechanism for CVD and environmental exposure. We recruited 203 preschool children (3-7 years) were enrolled from Guiyu (e-waste-exposed group, n = 105) and Haojiang (reference group, n = 98). Blood Pb levels and urinary PAH metabolites were measured. Percentages of T cells, CD4⁺ T cells and CD8⁺ T cells, complete blood counts, endothelial inflammation biomarker (serum S100A8/A9), and other inflammatory biomarkers [serum interleukin (IL)-6, IL-12p70, gamma interferon-inducible protein 10 (IP-10)] levels were evaluated. Blood Pb, total urinary hydroxylated PAH (ΣOHPAH), total hydroxynaphthalene (ΣOHNap) and total hydroxyfluorene (ΣOHFlu) levels, S100A8/A9, IL-6, IL-12p70 and IP-10 concentrations, absolute counts of monocytes, neutrophils, and leukocytes, as well as CD4⁺ T cell percentages were significantly higher in exposed children. Elevated blood Pb, urinary 2-hydroxynaphthalene (2-OHNap) and ΣOHFlu levels were associated with higher levels of IL-6, IL-12p70, IP-10, CD4⁺ T cell percentages, neutrophil and monocyte counts. Mediator models indicated that neutrophils exert the significant mediation effect on the relationship between blood Pb levels and S100A8/A9. IL-6 exerts a significant mediation effect on the relationship between blood Pb levels and IP-10, as well as the relationship between urinary ΣOHFlu levels and IP-10. Our results indicate that children with elevated exposure levels of Pb and PAHs have exacerbated vascular endothelial inflammation, which may indicate future CVD risk in e-waste recycling areas.

Therapeutic implications of how TNF links apolipoprotein E, phosphorylated tau, α-synuclein, amyloid-β and insulin resistance in neurodegenerative diseases

While cytokines such as TNF have long been recognized as essential to normal cerebral physiology, the implications of their chronic excessive production within the brain are now also increasingly appreciated. Syndromes as diverse as malaria and lead poisoning, as well as non‐infectious neurodegenerative diseases, illustrate this. These cytokines also orchestrate changes in tau, α‐synuclein, amyloid‐β levels and degree of insulin resistance in most neurodegenerative states. New data on the effects of salbutamol, an indirect anti‐TNF agent, on α‐synuclein and Parkinson's disease, APOE4 and tau add considerably to the rationale of the anti‐TNF approach to understanding, and treating, these diseases. Therapeutic advances being tested, and arguably useful for a number of the neurodegenerative diseases, include a reduction of excess cerebral TNF, whether directly, with a specific anti‐TNF biological agent such as etanercept via Batson's plexus, or indirectly via surgically implanting stem cells. Inhaled salbutamol also warrants investigating further across the neurodegenerative disease spectrum. It is now timely to integrate this range of new information across the neurodegenerative disease spectrum, rather than keep seeing it through the lens of individual disease states.

Lead (Pb) Exposure Enhances Expression of Factors Associated with Inflammation

The human immune system is constantly exposed to xenobiotics and pathogens from the environment. Although the mechanisms underlying their influence have already been at least partially recognized, the effects of some factors, such as lead (Pb), still need to be clarified. The results of many studies indicate that Pb has a negative effect on the immune system, and in our review, we summarize the most recent evidence that Pb can promote inflammatory response. We also discuss possible molecular and biochemical mechanisms of its proinflammatory action, including the influence of Pb on cytokine metabolism (interleukins IL-2, IL-4, IL-8, IL-1b, IL-6), interferon gamma (IFNγ), and tumor necrosis factor alpha (TNF-α); the activity and expression of enzymes involved in the inflammatory process (cyclooxygenases); and the effect on selected acute phase proteins: C-reactive protein (CRP), haptoglobin, and ceruloplasmin. We also discuss the influence of Pb on the immune system cells (T and B lymphocytes, macrophages, Langerhans cells) and the secretion of IgA, IgE, IgG, histamine, and endothelin.

Alteration of the number and percentage of innate immune cells in preschool children from an e-waste recycling area

Heavy metal lead (Pb) and cadmium (Cd) are widespread environmental contaminants and exert detrimental effects on the immune system. We evaluated the association between Pb/Cd exposures and innate immune cells in children from an electronic waste (e-waste) recycling area. A total number of 294 preschool children were recruited, including 153 children from Guiyu (e-waste exposed group), and 141 from Haojiang (reference group). Pb and Cd levels in peripheral blood were measured by graphite furnace atomic absorption spectrophotometer, NK cell percentages were detected by flow cytometer, and other innate immune cells including monocytes, eosinophils, neutrophils and basophils were immediately measured by automated hematology analyzer. Results showed children in Guiyu had significantly higher Pb and Cd levels than in reference group. Absolute counts of monocytes, eosinophils, neutrophils and basophils, as well as percentages of eosinophils and neutrophils were significantly higher in the Guiyu group. In contrast, NK cell percentages were significantly lower in Guiyu group. Pb elicited significant escalation in counts of monocytes, eosinophils and basophils, as well as percentages of monocytes, but decline in percentages of neutrophils in different quintiles with respect to the first quintile of Pb concentrations. Cd induced significant increase in counts and percentages of neutrophils in the highest quintile compared with the first quintile of Cd concentrations. We concluded alteration of the number and percentage of innate immune cells are linked to higher levels of Pb and Cd, which indicates Pb and Cd exposures might affect the innate and adaptive immune response in Guiyu children.

Heat-Processed Scutellariae Radix Protects Hepatic Inflammation through the Amelioration of Oxidative Stress in Lipopolysaccharide-Induced Mice

The present study evaluated the effects of heat-processed Scutellariae Radix (Scutellaria baicalensis) on lipopolysaccharide (LPS)-induced liver injury in mice. Scutellariae Radix heat-processed at 160[Formula: see text]C or 180[Formula: see text]C was orally administered at a dose of 100 mg/kg body weight for three days before the intraperitoneal injection of LPS, and the effects were compared with those of vehicle-treated LPS administered to control mice. The administration of Scutellariae Radix decreased the elevated serum monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), reactive oxygen species (ROS), nitrite/nitrate, peroxynitrite, and hepatic functional parameters, and reduced the increased ROS in the liver. The augmented expressions of hepatic oxidative stress and inflammation-related proteins, phospho-p38, phosphorylated extracellular signal-regulated kinase, phosphorylated c-Jun N-terminal kinase, nuclear factor-[Formula: see text] B p65, activator protein-1, cyclooxygenase-2, inducible nitric oxide synthase, MCP-1, intercellular adhesion molecule-1, tumor necrosis factor-[Formula: see text], and IL-6, were downregulated by the heat-processed Scutellariae Radix. Hematoxylin-eosin staining showed that the increased hepatocellular damage in the liver of LPS-treated mice improved with the administration of heat-processed Scutellariae Radix. Overall, the ameliorative effects of Scutellariae Radix were superior to those when heat-processed at 180[Formula: see text]C. Our results indicate that heat-processed Scutellariae Radix acts as an anti-inflammatory agent by ameliorating oxidative stress in the liver of mice with LPS-induced liver injury.

Amyloid β: one of three danger-associated molecules that are secondary inducers of the proinflammatory cytokines that mediate Alzheimer's disease

This review concerns how the primary inflammation preceding the generation of certain key damage-associated molecular patterns (DAMPs) arises in Alzheimer's disease (AD). In doing so, it places soluble amyloid β (Aβ), a protein hitherto considered as a primary initiator of AD, in a novel perspective. We note here that increased soluble Aβ is one of the proinflammatory cytokine-induced DAMPs recognized by at least one of the toll-like receptors on and in various cell types. Moreover, Aβ is best regarded as belonging to a class of DAMPs, as do the S100 proteins and HMBG1, that further exacerbate production of these same proinflammatory cytokines, which are already enhanced, and induces them further. Moreover, variation in levels of other DAMPs of this same class in AD may explain why normal elderly patients can exhibit high Aβ plaque levels, and why removing Aβ or its plaque does not retard disease progression. It may also explain why mouse transgenic models, having been designed to generate high Aβ, can be treated successfully by this approach.

Amelioration of lipopolysaccharide-induced liver injury by aqueous rooibos (Aspalathus linearis) extract via inhibition of pro-inflammatory cytokines and oxidative stress

BACKGROUND

Acute liver injury occur after intraperitoneal administration of lipopolysaccharide (LPS). Oxidative stress and release of pro-inflammatory cytokines are both implicated in the pathogenesis of LPS-induced acute liver injury. This study investigated the ameliorative effect of fermented rooibos (Aspalathus linearis) extract on LPS-induced acute liver injury.

METHOD

Major phenolic compounds in the fermented rooibos extract by HPLC-DAD, as well as the in vitro antioxidant capacity were quantified before the start of the experiment. Male Wistar rats were randomized into 4 groups (n = 10 per group) and given either water or fermented rooibos extract for 4 weeks before LPS injection. Hepatic function markers, including aminotransferases and lactate dehydrogenase, lipid peroxidation markers, antioxidant enzymes, glutathione redox status, as well as cytokine levels were monitored in the rats.

RESULTS

Injection of LPS significantly increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH). Oxidative stress, evidenced by increased thiobarbituric acid reactive substances (TBARS) measured as malondialdehyde (MDA) in plasma and liver, and decreased glutathione redox status (GSH: GSSG ratio) in whole blood and liver was induced in LPS-challenged rats. Furthermore, hepatic levels of pro-inflammatory response markers TNF-α, IL-1β and IL-6 were increased significantly. Pre-feeding the fermented rooibos extract for 4 weeks decreased LPS-induced elevated levels of serum AST and LDH (significantly, p < 0.05) as well as ALT marginally. Consuming rooibos caused an attenuation of the observed increase in plasma and hepatic MDA, decrease in whole blood and liver GSH:GSSG ratio, as well as the changes noted in various antioxidant enzymes. The elevation in TNF-α and IL-6 was significantly suppressed, indicating an inhibition of the induced inflammatory response by rooibos.

CONCLUSION

Overall, our data showed that aqueous rooibos extract attenuated LPS-induced liver injury possibly by modulating oxidative stress and suppressing pro-inflammatory cytokines formation.

Lead modulation of macrophages causes multiorgan detrimental health effects

The environmental toxicant lead (Pb) has detrimental effects on a number of organ systems, including the immune system. Pb exposure decreases host immune defenses against numerous microorganisms and cancer. Although Pb effects on humoral and cell-mediated immunity as well as on erythrocyte, neural, and renal pathophysiology have been well documented, there are few reports regarding Pb's impact on innate immunity, which can affect multiorgan processes. This review focuses on Pb modulation of a key innate immune cell, the macrophage. The impact of Pb on macrophages in different organs, on immature versus mature macrophages, and on low versus high Pb concentrations is discussed. Pb decreases phagocytosis and chemotaxis of macrophages and affects nitric oxide production and eicosanoid metabolism in mature macrophages. Pretreatment of macrophages with Pb increases TNF-α secretion after in vitro stimulation with lipopolysaccharide; however, Pb exposure decreases in vivo intracellular pathogen killing. More recent evidence from mouse studies indicates that even low, environmentally relevant, blood concentrations of Pb result in increased phagocytosis of erythrocytes and decreased expression of interferon-gamma-inducible GTPases, p65-GBP, and p47-IRG, which are necessary for intracellular pathogen killing. Taking into account the effects of Pb on macrophages, the review describes posited mechanisms to account for Pb-altered health effects; Pb effects on heme levels may play a key role as well as Pb's preferential induction of helper type-2 T (Th2) cells and M2 macrophages, which is related to oxidative stress. The discussion links old findings with new, thereby adding new insight into the effects of Pb on macrophages and the resultant compromised immunity and health.

Treatment implications of the altered cytokine-insulin axis in neurodegenerative disease

The disappointments of a series of large anti-amyloid trials have brought home the point that until the driving force behind Alzheimer's disease, and the way it causes harm, are firmly established and accepted, researchers will remain ill-equipped to find a way to treat patients successfully. The origin of inflammation in neurodegenerative diseases is still an open question. We champion and expand the argument that a shift in intracellular location of α-synuclein, thereby moving a key methylation enzyme from the nucleus, provides global hypomethylation of patients' cerebral DNA that, through being sensed by TLR9, initiates production of the cytokines that drive these cerebral inflammatory states. After providing a background on the relevant inflammatory cytokines, this commentary then discusses many of the known alternatives to the primary amyloid argument of the pathogenesis of Alzheimer's disease, and the treatment approaches they provide. A key point to appreciate is the weight of evidence that inflammatory cytokines, largely through increasing insulin resistance and thereby reducing the strength of the ubiquitously important signaling mediated by insulin, bring together most of these treatments under development for neurodegenerative disease under the one roof. Moreover, the principles involved apply to a wide range of inflammatory diseases on both sides of the blood brain barrier.

Beneficial effect of sesame oil on heavy metal toxicity

Heavy metals become toxic when they are not metabolized by the body and accumulate in the soft tissue. Chelation therapy is mainly for the management of heavy metal-induced toxicity; however, it usually causes adverse effects or completely blocks the vital function of the particular metal chelated. Much attention has been paid to the development of chelating agents from natural sources to counteract lead- and iron-induced hepatic and renal damage. Sesame oil (a natural edible oil) and sesamol (an active antioxidant) are potently beneficial for treating lead- and iron-induced hepatic and renal toxicity and have no adverse effects. Sesame oil and sesamol significantly inhibit iron-induced lipid peroxidation by inhibiting the xanthine oxidase, nitric oxide, superoxide anion, and hydroxyl radical generation. In addition, sesame oil is a potent inhibitor of proinflammatory mediators, and it attenuates lead-induced hepatic damage by inhibiting nitric oxide, tumor necrosis factor-α, and interleukin-1β levels. Because metal chelating therapy is associated with adverse effects, treating heavy metal toxicity in addition with sesame oil and sesamol may be better alternatives. This review deals with the possible use and beneficial effects of sesame oil and sesamol during heavy metal toxicity treatment.

Polydatin Protects against Lipopolysaccharide-Induced Fulminant Hepatic Failure in D-Galactosamine-Sensitized Mice

Fulminant hepatic failure (FHF) is a devastating clinical syndrome with extremely poor prognosis and high mortality. Therefore, better treatment is urgently needed. Polydatin (PD), a traditional anti-inflammatory drug, has been described to protect against liver injury induced by certain hepatotoxins. The present study investigated the protective effect of PD against lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced FHF in mice and the underlying mechanism. Mice were pretreated with an increasing dose of PD (10, 30, and 100 mg/kg), following LPS/D-GalN challenge. The liver injury was assessed biochemically and histologically. We found that PD exerted a protective effect on LPS/D-GalN-induced FHF as evidenced by reducing sera alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities, diminishing liver histopathological injury, and lowering mortality in a dose-dependent manner. In addition, pretreatment mice with PD dose-dependently suppressed tumor necrosis factor-α (TNF-α) production, myeloperoxidase (MPO) activity, intercellular adhesion molecule-1 (ICAM-1) and endothelial cell adhesion molecule-1 (ECAM-1) expression, caspase-3 activation, and transcription factor nuclear factor-kappa B(NF-kB) activity induced by LPS. These results suggested that PD could effectively protect from LPS/D-GalN-induced FHF and the protective effect afforded by PD probably contributed to reduce TNF-α production via inhibiting NF-kB activation.

Ubiquitous hazardous metal lead induces TNF-α in human phagocytic THP-1 cells: primary role of ERK 1/2

Induction of tumor necrosis factor-α (TNF-α) in response to lead (Pb) exposure has been implicated in its immunotoxicity. However, the molecular mechanism by which Pb upregulates the level of TNF-α is wagely known. An attempt was therefore made to elucidate the mechanistic aspect of TNF-α induction, mainly focusing transcriptional and post transcriptional regulation via mitogen activated protein kinases (MAPKs) activation. We observed that exposure of Pb to human monocytic THP-1 cells resulted in significant enhanced production of TNF-α m-RNA and protein secretion. Moreover, the stability of TNF-α m-RNA was also increased as indicated by its half life. Notably, activation of ERK 1/2, p38 and JNK in Pb exposed THP-1 was also evident. Specific inhibitor of ERK1/2, PD 98059 caused significant inhibition in production and stability of TNF-α m-RNA. However, SB 203580 partially inhibited production and stability of TNF-α m-RNA. Interestingly, a combined exposure of these two inhibitors completely blocked modulation of TNF-α m-RNA. Data tends to suggest that expression and stability of TNF-α induction due to Pb exposure is mainly regulated through ERK. Briefly, these observations are useful in understanding some mechanistic aspects of proinflammatory and immunotoxicity of Pb, a globally acknowledged key environmental contaminant.

Early life environment and developmental immunotoxicity in inflammatory dysfunction and disease

Components of the innate immune system such as macrophages and dendritic cells are instrumental in determining the fate of immune responses and are, also, among the most sensitive targets of early life environmental alterations including developmental immunotoxicity (DIT). DIT can impede innate immune cell maturation, disrupt tissue microenvironment, alter immune responses to infectious challenges, and disrupt regulatory responses. Dysregulation of inflammation, such as that observed with DIT, has been linked with an increased risk of chronic inflammatory diseases in both children and adults. In this review, we discuss the relationship between early-life risk factors for innate immune modulation and promotion of dysregulated inflammation associated with chronic inflammatory disease. The health risks from DIT-associated inflammation may extend beyond primary immune dysfunction to include an elevated risk of several later-life, inflammatory-mediated diseases that target a wide range of physiological systems and organs. For this reason, determination of innate immune status should be an integral part of drug and chemical safety evaluation.

SESAME OIL PROTECTS AGAINST LEAD-PLUS-LIPOPOLYSACCHARIDE-INDUCED ACUTE HEPATIC INJURY

Lead (Pb) increases lipopolysaccharide (LPS)-induced tumor necrosis factor alpha, which causes liver damage. In this study, we investigated the effect of sesame oil on Pb-plus-LPS (Pb + LPS)-induced acute liver damage in mice. Mice were given sesame oil (8 mL/kg orally) just after Pb acetate (10 mmol/kg i.p.) plus LPS (5 mg/kg i.p.). Aspartate aminotransferase, alanine aminotransferase, tumor necrosis factor-alpha, interleukin-1beta, nitric oxide, and inducible nitric oxide synthase levels were examined. Sesame oil significantly decreased serum aspartate aminotransferase and alanine aminotransferase levels in Pb + LPS-stimulated mice. Sesame oil reduced Pb + LPS-induced tumor necrosis factor-alpha, interleukin-1beta, and nitric oxide production in serum and liver tissue. Furthermore, sesame oil decreased inducible nitric oxide synthase expression in leukocytes and liver tissue in Pb + LPS-treated mice. We hypothesize that the inhibition of proinflammatory cytokines and nitric oxide might be involved in sesame oil-associated protection against Pb + LPS-induced acute hepatic injury in mice.