Stefania Catania

Exposure of human skin to benzo[a]pyrene: role of CYP1A1 and aryl hydrocarbon receptor in oxidative stress generation.

Exposure to benzo[a]pyrene (BaP) can induce inflammatory skin diseases and skin cancer, which are both associated to oxidative stress. BaP is known to bind with high specificity to the aryl hydrocarbon receptor (AhR), modifying the expression of CYP1A1, involved both in cancer and inflammation. While the current knowledge is based on murine skin and cell culture data, in this study human healthy skin has been treated with 5muM BaP in conditions simulating occupational and environmental exposure. AhR and CYP1A1 expression was evaluated by Western blotting, which revealed their presence even in control untreated skin; both enzyme and receptor increased more than twofold after exposure to BaP. AhR expression level was lower than CYP1A1 in basal conditions and following induction. Oxidative stress was evaluated in terms of MTT reduction, protein peroxidation and reactive oxygen species (ROS) formation. A significant increase in ROS and carbonyl compound production, as well as reduced tissue viability have been determined by BaP. The results of this experiment indicate that BaP, an AhR agonist, can significantly increase receptor and CYP1A1 expression and induce oxidative stress in human skin, confirming the involvement of this pathway in the pathogenesis of tissue damage due to polycyclic aromatic hydrocarbons.

Cytokine patterns in greenhouse workers occupationally exposed to α-cypermethrin: an observational study.

The immunotoxicity of the synthetic pyrethroid α-cypermethrin (αCYP) was assessed in 30 occupationally exposed greenhouse workers and 30 non-exposed controls by comparing plasma levels of IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p70, TNF-α, TNF-β and INF-γ. Urinary 3-phenoxybenzoic acid was used as an exposure biomarker. Exposed workers showed neither clinical signs of immunosuppression nor alterations in total leukocytes or leukocyte subpopulations, whereas significant differences (p<0.05) were found for IL-12p70 and highly significant differences (p<0.001) for INF-γ, IL-2 and IL-8, which are involved in antitumor immunity and response to infection. Proinflammatory cytokines IL-2, IL-8, IL-12p70 and IFN-γ play a significant role against infection and cancer. We report the first data on the ability of αCYP to reduce proinflammatory cytokine levels in an exposed healthy human population. Findings support the hypothesis that pyrethroid exposure may reduce host defenses against infection and cancer, particularly in subjects with impaired immune capacity.

Antiproliferative Activity of the Dietary Isothiocyanate Erucin, a Bioactive Compound from Cruciferous Vegetables, on Human Prostate Cancer Cells

It is becoming increasingly clear that many dietary agents, such as isothiocyanates (ITCs) from cruciferous vegetables, can retard or prevent the process of prostate carcinogenesis. Erucin (ER) is a dietary ITC, which has been recently considered a promising cancer chemopreventive phytochemical. The potential protective activity of ER against prostate cancer was investigated using prostate adenocarcinoma cells (PC3), to analyze its effects on pathways involved in cell growth regulation, such as the cyclin-dependent kinase (CDKs) inhibitor p21WAF1/CIP1 (p21), phosphatidylinositol-3 kinase/AKT, and extracellular signal-regulated kinases (ERK)1/2 signaling pathways. We have shown for the first time that ER increases significantly p21 protein expression and ERK1/2 phosphorylation in a dose-dependent manner to inhibit PC3 cell proliferation (P ≤ 0.01). Compared to the structurally related sulforaphane, a well-studied broccoli-derived ITC, ER showed lower potency in inhibiting proliferation of PC3 cells, as well as in modulating p21 and pERK1/2 protein levels. Neither of the naturally occurring ITCs was able to affect significantly pAKT protein levels in prostate cells at all concentrations tested (0–25 μM). It is clearly important for the translation of laboratory findings to clinical approaches to investigate in animal and cell studies the molecular mechanisms by which ITCs may exert health promoting effects.

IL-17 and IL-22 serum levels in greenhouse workers exposed to pesticides.

IntroductionAltered immune function may be an indicator of increased potential for the development of immunologically based diseases such as cancer, hypersensitivity and autoimmunity.Materials and methods To investigate whether Th17 and Th22 cells are targeted by pesticide exposure, we analyzed IL-17 and IL-22 serum levels in a population of 64 greenhouse workers.Results and conclusion A significant increase in IL-22 concentration was observed in serum of the exposed subjects compared to controls. These findings support the hypothesis that exposure to pesticides may reduce host defenses against infections and cancer.

Antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben plant extracts

This study reported the antimicrobial activity and phenolic content of natural site and micropropagated Limonium avei (De Not.) Brullo & Erben inflorescences. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethanolic extracts were determined according to the Clinical Laboratory Standards Institute guidelines. Individual phenolic acids and flavonoids were detected by a high performance liquid chromatography (HPLC-DAD) method. The samples showed a comparable antimicrobial activity, although the natural site extract possessed the lower MIC values. The best activity was detected against Gram-positive bacteria, such as Staphylococcus aureus including methicillin resistant strains (MIC and MBC values ranging from 7.81 to 62.50 µg mL−1 and from 500 to 2000 µg mL−1 respectively). In contrast, a low activity was found on Gram-negative bacteria and Candida albicans. The HPLC-DAD analysis revealed ten phenolic acids and four flavonoids with a major amount of m-coumaric acid, naringin and quercetin in the natural site extract.

Changes Induced by Exposure of the Human Lung to Glass Fiber-Reinforced Plastic

The inhalation of glass dusts mixed in resin, generally known as glass fiber–reinforced plastic (GRP), represents a little-studied occupational hazard. The few studies performed have highlighted nonspecific lung disorders in animals and in humans. In the present study we evaluated the alteration of the respiratory system and the pathogenic mechanisms causing the changes in a group of working men employed in different GRP processing operations and exposed to production dusts. The study was conducted on a sample of 29 male subjects whose mean age was 37 years and mean length of service 11 years. All of the subjects were submitted to a clinical check-up, basic tests, and bronchoalveolar lavage (BAL); microscopic studies and biochemical analysis were performed on the BAL fluid. Tests of respiratory function showed a large number of obstructive syndromes; scanning electron microscopy highlighted qualitative and quantitative alterations of the alveolar macrophages; and transmission electron microscopy revealed the presence of electron-dense cytoplasmatic inclusions indicating intense and active phlogosis (external inflammation). Biochemical analyses highlighted an increase in protein content associated with alterations of the lung oxidant/antioxidant homeostasis. Inhalation of GRP, independent of environmental concentration, causes alterations of the cellular and humoral components of pulmonary interstitium; these alterations are identified microscopically as acute alveolitis.

Modifications in the metabolic pathways of benzene in streptozotocin-induced diabetic rat.

Abstract Benzene is a ubiquitous environmental pollutant primarily metabolized by a cytochrome P-450 (CYP-450) isoenzyme, CYP-450 IIE1. A consistent induction of CYP450 IIE1 has been observed in both rat and human affected by diabetes mellitus. The aim of this study was to evaluate whether streptozotocin (STZ)-induced diabetes determines modifications in the metabolic pathways of benzene in rat. Benzene (100 mg/kg per day, dissolved in corn oil) was administered i.p. once a day for 5 days. Urine samples were collected every day in STZ-treated and normoglycaemic animals, treated and untreated with benzene (n = 10). Urinary levels of trans,trans-muconic acid and of phenol, catechol and hydroquinone (free and conjugated with sulphuryl and glucuronic group) were measured by high-performance liquid chromatography (HPLC). In normoglycaemic rats during the 5 days of treatment with benzene we observed a progressive and significant decrement in the urinary excretion of phenol, phenyl sulphate and glucuronide, catechol, catechol glucuronide, hydroquinone, hydroquinone glucuronide and t,t-muconic acid (P < 0.05). In the diabetic animals, conversely, the same metabolites showed progressively increasing urinary levels (P < 0.05). Catechol sulphate and hydroquinone sulphate levels were below the instruments detection limit. In the comparison between diabetic and normoglycaemic benzene treated rats, the inter-group difference was significant (P < 0.05) from day 3 of treatment for t,t-muconic acid, and from day 1 for free and conjugated phenol, free and glucuronide catechol and free hydroquinone. In the normoglycaemic rat exposed to benzene the decreasing trend observed in urinary excretion of free and conjugated metabolites may be due to their capability to reduce cytochromial activity. Conversely, in the diabetic rat, urinary levels of benzene metabolites tended to increase progressively, probably due to the consistent induction of CYP-450 IIE1 observed in diabetes, which would overwhelm the inhibition of this isoenzyme caused by phenolic metabolites. Furthermore, the metabolic switch towards detoxification metabolites observed after administration of high doses of benzene is not allowed in the diabetic because of reduced glutathione-S-transferase activity. As a consequence, higher levels of hydroquinone, phenol and catechol, considered the actual metabolites responsibles for benzene toxicity, will accumulate in the diabetic rat. Extrapolating these data to human, we may thus suggest that occupational exposure to benzene of a diabetic subject poses a higher risk level, as his metabolism tends to produce and accumulate higher levels of reactive benzene catabolites.

Cytotoxicity evaluation after coexposure to perchloroethylene and selected peroxidant drugs in rat hepatocytes

There is evidence of hepatotoxic effects caused by Perchloroethylene (PCE), presumably due to reactive metabolic intermediates; lipid peroxidation is under study as a potential mechanism of toxicity. We aimed to verify if PCE levels comparable to those reached in the blood of exposed subjects can cause cell damage and lipid peroxidation. The association of PCE with lipid peroxidation inducing drugs (cyclosporine A, valproic acid and amiodarone) was also tested on rat isolated hepatocytes. AST and LDH release, MTT test and lipid peroxidation assay showed that PCE determines dose-dependent effects on rat isolated hepatocytes. The toxic potential resulting from our data would be valproic acid < cyclosporine A < amiodarone. While valproic acid and cyclosporine caused a mild toxicity, the effects of amiodarone were more severe; in particular, the association of PCE with amiodarone showed a clear additive effect. The role of lipid peroxidation in the liver toxicity exerted by the tested compounds was confirmed by our data, and resulted relevant after treatment of cells with amiodarone and PCE. Extrapolating these results to human, we can suggest that a subject professionally exposed to PCE, who chronically assumes a lipid peroxidation inducing drug like amiodarone, may be potentially exposed to a higher risk of liver toxicity.

Release of nickel and chromium in common foods during cooking in 18/10 (grade 316) stainless steel pots

Literature data on the release of nickel and chromium from stainless steel cookware during food preparation are contrasting, have often been obtained with uncommon foods and/or procedures, and are thus not widely applicable.

Contribution of the glucosinolate fraction to the overall antioxidant potential, cytoprotection against oxidative insult and antimicrobial activity of Eruca sativa Mill. leaves extract

Background: Eruca sativa Mill. (Brassicaceae) is commonly utilized as an ingredient in salads and also as a folk remedy to treat various diseases. Objective: The objective of this study was to establish the contribution of the glucosinolate (GLS) fraction to the overall antioxidant, cytoprotection against oxidative insult and antimicrobial properties of the hydro-alcoholic extract of E. sativa leaves from Sicily (Italy), characterized phytochemically. Materials and Methods: The antioxidant activity was evaluated by different in vitro systems. The cytoprotective effect against hydrogen peroxide (H2O2)-induced oxidative stress was tested in human peripheral blood mononuclear cells (PBMCs). The antimicrobial potential against bacteria and fungi was assayed by standard methods. Results: E. sativa extract exhibited both radical scavenging (50% inhibitory concentration [IC50] 1.04 ± 0.04 mg/mL) and ferrous ions-chelating activity (IC50 0.327 ± 0.0032 mg/mL) and mild reducing power; the GLS fraction showed chelating ability only (IC50 0.225 ± 0.009 mg/mL). In the experimental model of H2O2-induced oxidative stress in human PBMCs, a significant cytoprotective effect and a suppression of reactive oxygen species production by both extract and GLS fraction were observed (P < 0.001). E. sativa extract displayed moderate antimicrobial activity against Gram-positive bacteria, and Staphylococcus aureus was the most sensitive strain (minimum inhibitory concentration 0.125 mg/mL), whereas the GLS fraction was not active. Conclusion: GLSs are not involved in the primary antioxidant activity of E. sativa leaf extract but they are, almost in part, responsible for its ferrous ion-chelating properties. Iron-chelating compounds in E. sativa extract may protect cells under conditions of oxidative stress, and GLSs might play a chief role in this effect. Abbreviations used: GLS: Glucosinolate; H2O2: Hydrogen peroxide; PBMCs: Peripheral blood mononuclear cells; IC50: 50% inhibitory concentration; MIC: Minimum inhibitory concentration.