Risk assessment for migration of styrene oligomers into food from polystyrene food containers.

Regulation EU 10/2011 requires a risk assessment of Non Intentionally Added Substances (NIAS) migrating into food for food contact plastics within the EU. Styrene oligomers are important potential components of NIAS in polystyrene used for food packaging and so far only dimers and trimers have been identified. They are not genotoxic in vitro, and there is good evidence that they are not endocrine disruptors. Hazard characterization to establish "safe" exposure levels is based on 1. The No Adverse Effect Level (NOAEL) of 1 mg/kg bw/d in an oral rat study during pregnancy and lactation and 2. The concept of Threshold of Toxicological Concern (TTC). Likely human exposure is derived from 1. the concentrations of dimers and trimers in food simulants or 2. in food and 3. the probabilistic FACET exposure estimation based on dimer and trimer concentrations in polystyrene and their potential for migration. The Margin of Safety as the relation of potential consumer exposure and the "safe" exposure level was always above 1 (apart from migration with 95% ethanol which is no longer recommended as an official food simulant for overall migration into fatty food) demonstrating that dimers and trimers in PS food packaging present a low risk for consumers.

Oligomers of styrene are not endocrine disruptors.

Oligomers of styrene have been identified in polystyrene (PS) polymer samples intended for food packaging. Such oligomers contribute to nonintentionally added substances (NIAS) that may migrate into food or food simulants and therefore have to be assessed for the potential risk to health. No oligomers larger than dimers and trimers of styrene have been found to be present in PS. Some in vivo and in vitro information indicative of an endocrine activity for some specific oligomers suggest concerns for their potential for endocrine disruption in humans. Data on endocrine activity available from in vitro and in vivo screening approaches and from non-guideline studies in experimental animals were evaluated. The different test methods were classified according to the OECD Conceptual Framework for Testing and Assessment of Endocrine Disruptors (OECD) and the ranking system of Borgert et al. proposed in 2014. The quality and reliability of each study is further assessed by professional judgment. The integration of the total information supports the conclusion that neither specific oligomers, nor their mixtures, potentially migrating into food are endocrine disruptors according to the definition of EFSA and WHO/IPCS.

Thrombin-activatable fibrinolysis inhibitor protects against acute lung injury by inhibiting the complement system.

Acute lung injury (ALI) is a devastating disease with an overall mortality rate of 30 to 40%. The coagulation/fibrinolysis system is implicated in the pathogenesis of ALI. Thrombin-activatable fibronolysis inhibitor (TAFI) is an important component of the fibrinolysis system. Recent studies have shown that the active form of TAFI can also regulate inflammatory responses by its ability to inhibit complement C3a, C5a, and osteopontin. We hypothesized that TAFI might have a protective role in ALI. To demonstrate this hypothesis, the development of ALI was compared between wild-type (WT) and TAFI-deficient mice. ALI was induced by intratracheal instillation of LPS. Control mice were treated with saline. Animals were killed 24 hours after LPS. The number of inflammatory cells and the concentration of total protein and inflammatory cytokines were significantly increased in bronchoalveolar lavage fluid from LPS-treated, TAFI-deficient mice compared with their WT counterparts. Significantly higher concentrations of C5a were found in bronchoalveolar lavage fluid and plasma in LPS-treated TAFI knockout mice compared with WT mice. Pretreatment with inhaled C5a receptor antagonist blocked the detrimental effects of TAFI deficiency to levels found in WT mice. Our results show that TAFI protects against ALI, at least in part, by inhibiting the complement system.

Eosinophils promote epithelial to mesenchymal transition of bronchial epithelial cells.

Eosinophilic inflammation and remodeling of the airways including subepithelial fibrosis and myofibroblast hyperplasia are characteristic pathological findings of bronchial asthma. Epithelial to mesenchymal transition (EMT) plays a critical role in airway remodelling. In this study, we hypothesized that infiltrating eosinophils promote airway remodelling in bronchial asthma. To demonstrate this hypothesis we evaluated the effect of eosinophils on EMT by in vitro and in vivo studies. EMT was assessed in mice that received intra-tracheal instillation of mouse bone marrow derived eosinophils and in human bronchial epithelial cells co-cultured with eosinophils freshly purified from healthy individuals or with eosinophilic leukemia cell lines. Intra-tracheal instillation of eosinophils was associated with enhanced bronchial inflammation and fibrosis and increased lung concentration of growth factors. Mice instilled with eosinophils pre-treated with transforming growth factor(TGF)-ß1 siRNA had decreased bronchial wall fibrosis compared to controls. EMT was induced in bronchial epithelial cells co-cultured with human eosinophils and it was associated with increased expression of TGF-ß1 and Smad3 phosphorylation in the bronchial epithelial cells. Treatment with anti-TGF-ß1 antibody blocked EMT in bronchial epithelial cells. Eosinophils induced EMT in bronchial epithelial cells, suggesting their contribution to the pathogenesis of airway remodelling.

Differential role of regulatory T cells in early and late stages of pulmonary fibrosis.

Regulatory T cells (Tregs) are a specific subset of T lymphocytes that regulate the function of other subsets of lymphocytes. Contradictory results have been reported regarding the role of Tregs in lung fibrosis. We wished to clarify the role of Tregs in the early and late stages of bleomycin-induced lung fibrosis in mice by depleting them with anti-CD25+ antibody (PC61). Mice treated with PC61 in early stages had significantly decreased number of CD4+CD25+ T cells compared to mice treated with the isotype control. The number of inflammatory cells, the concentrations of collagen, TGFß1, the content of collagen and hydroxyproline in lung tissue were significantly reduced in PC61-treated mice compared to mice treated with the isotype control group. Pathological examination of the lung also disclosed reduced fibrotic changes and decreased fibrosis score in the PC61 group compared to control group. By contrast, mice treated with PC61 in late stages of the disease showed more infiltration of inflammatory cells and higher fibrotic score and hydroxyproline content in the lungs than mice treated with the isotype control. Our results suggest that Tregs play a detrimental role in early stages but protective role in late stages of pulmonary fibrosis in mice.

Role of thrombin-activatable fibrinolysis inhibitor in allergic bronchial asthma.

BACKGROUND: Bronchial asthma is an inflammatory disease of the airways. Thrombin-activatable fibrinolysis inhibitor (TAFI) is a carboxypeptidase that besides inhibiting fibrinolysis, also regulates inflammatory processes. The only validated substrate known for TAFI is fibrin. In the present study we evaluated the role of TAFI in bronchial asthma by comparing the development of allergic bronchial asthma between wild-type (WT) and TAFI-deficient mice (KO). METHODS: Asthmatic inflammation was induced by sensitization and challenge with ovalbumin in WT (WT/OVA) and TAFI KO (KO/OVA) mice. WT mice (WT/SAL) and TAFI KO (KO/SAL) were used as controls. Cytokines, markers of inflammation, and coagulation were measured in bronchoalveolar lavage fluid (BALF). RESULTS: Airway hyperresponsiveness was worse in KO/OVA mice than in WT/OVA mice or control mice. Markers of lung injury were significantly increased in BALF from KO/OVA mice compared to WT/OVA mice. Airway hyperresponsiveness and the BALF concentrations of IL-5 and osteopontin were significantly increased in KO/OVA mice compared to WT/OVA mice. Treatment of WT/OVA and KO/OVA mice with a C5a receptor antagonist significantly decreased hyperresponsiveness along with the BALF concentrations of total protein and C5a compared to untreated asthmatic mice. CONCLUSION: The results of this study suggest that TAFI plays a protective role in the pathogenesis of allergic inflammation probably by inhibiting the complement system.

Development and preclinical efficacy of novel transforming growth factor-ß1 short interfering RNAs for pulmonary fibrosis.

Idiopathic pulmonary fibrosis is a chronic devastating disease of unknown etiology. No therapy is currently available. A growing body of evidence supports the role of transforming growth factor (TGF)-ß1 as the major player in the pathogenesis of the disease. However, attempts to control its expression and to improve the outcome of pulmonary fibrosis have been disappointing. We tested the hypothesis that TGF-ß1 is the dominant factor in the acute and chronic phases of pulmonary fibrosis and developed short interfering (si)RNAs directed toward molecules implicated in the disease. This study developed novel sequences of siRNAs targeting the TGF-ß1 gene and evaluated their therapeutic efficacy in two models of pulmonary fibrosis: a model induced by bleomycin and a novel model of the disease developed spontaneously in mice overexpressing the full length of human TGF-ß1 in the lungs. Intrapulmonary delivery of aerosolized siRNAs of TGF-ß1 with sequences common to humans and rodents significantly inhibited bleomycin-induced pulmonary fibrosis in the acute and chronic phases of the disease and in a dose-dependent manner. Aerosolized human-specific siRNA also efficiently inhibited pulmonary fibrosis, improved lung function, and prolonged survival in human TGF-ß1 transgenic mice. Mice showed no off-target effects after intratracheal administration of siRNA. These results suggest the applicability of these novel siRNAs as tools for treating pulmonary fibrosis in humans.