Immunological determinants in a mouse model of chemical-induced asthma after multiple exposures

In a mouse model of chemical-induced asthma, we investigated the effects of multiple challenges, using toluene diisocyanate (TDI), a known cause of occupational asthma. On days 1 and 7, BALB/c mice received TDI or vehicle (acetone/olive oil). On days 10, 13 and 16 the mice received an intranasal instillation of TDI. Ventilatory function (Penh) was monitored by whole body plethysmography for 40 min after each challenge. Reactivity to methacholine was measured 22 h later. Pulmonary inflammation, TNF-\u3b1 and MIP-2 levels were assessed 24 h after the last challenge by broncho-alveolar lavage (BAL). Other immunological parameters included total IgE, lymphocyte sub-populations in auricular and cervical lymph nodes, and IL-4, IFN-\u3b3 and IL-13 levels in supernatants of lymph node cells, cultured with or without concanavalin A. Early ventilatory function and airway reactivity increased in all groups that received a dermal application and one or multiple intranasal challenges of TDI. After multiple challenges, lung inflammation was characterized by neutrophils ( 3c15%), and eosinophils ( 3c4%), along with an increase in BAL MIP-2 and TNF-\u3b1 levels. The auricular and cervical lymph node cells of all sensitized mice showed an increase in B cells, Th cells and an increased concentration of in vitro release of IL-4, IFN-\u3b3 and IL-13 after stimulation with concanavalin A. Total serum IgE was elevated in dermally TDI-sensitized mice. This protocol including multiple challenges results in a model that resembles human asthma, indicating that responses found in the model using a single challenge could be a good first indication for the development of asthma

Respiratory response to toluene diisocyanate depends on prior frequency and concentration of dermal sensitization in mice

Occupational asthma is the principal cause of work-related respiratory disease in the industrial world. In the absence of satisfactory models for predicting the potential of low molecular weight chemicals to cause asthma, we verified that dermal sensitization prior to intranasal challenge influences the respiratory response using toluene diisocyanate (TDI), a known respiratory sensitizer. BALB/c mice received TDI or vehicle (acetone/olive oil) on each ear on three consecutive days (days 1, 2, and 3; 0.3 or 3% TDI) or only once (day 1, 1% TDI). On day 7, the mice received similar dermal applications of vehicle or the same concentration of TDI as before ("boost"). On day 10, they received an intranasal dose of TDI (0.1%) or vehicle. Ventilatory function was monitored by whole body plethysmography for 40 min after intranasal application, and reactivity to inhaled methacholine was assessed 24 h later. Pulmonary inflammation was assessed by bronchoalveolar lavage and histology. Mice that received an intranasal dose of TDI without having received a prior dermal application of TDI did not exhibit any ventilatory response or inflammatory changes compared to vehicle controls. In contrast, mice that had received prior application(s) of TDI, even if only on day 7, exhibited the following: ventilatory responses, compatible with bronchoconstriction, immediately after intranasal application with TDI; enhanced methacholine responsiveness 24 h later; and pulmonary inflammation characterized by neutrophils. This was, however, not the case in mice that received the highest dermal amount of TDI (3% on days 1, 2, and 3). These findings suggest that respiratory response to TDI depends on prior frequency and concentration of dermal sensitization in mice

Validation of a mouse model of chemical-induced asthma using trimellitic anhydride, a respiratory sensitizer, and dinitrochlorobenzene, a dermal sensitizer

Background: Occupational asthma can be caused by chemicals. Previously, we established a murine model of immunologically mediated chemical-induced asthma using toluene diisocyanate. Objective: We sought to verify this model using trimellitic anhydride (TMA), a respiratory sensitizer, and 1-chloro-2,4-dinitrobenzene (DNCB), a dermal sensitizer. Methods: BALB/c mice received dermal applications (vehicle or chemical) on days 1 and 7. On day 10, they received an intranasal instillation (vehicle or chemical). Whole-body plethysmography (enhanced pause) was used to monitor changes in ventilatory function and methacholine reactivity. Pulmonary inflammation was assessed by using bronchoalveolar lavage (cells, TNF-\u3b1 levels, and macrophage inflammatory protein 2 levels). Immunologic parameters included total serum IgE levels, lymphocyte distribution in auricular and cervical lymph nodes, and IL-4 and IFN-\u3b3 levels in supernatants of lymph node cells incubated with or without concanavalin A. Results: Mice dermally treated and intranasally challenged with TMA experienced markedly increased enhanced pause immediately after intranasal challenge and increased methacholine reactivity (24 hours later). Mice similarly treated with DNCB did not show any ventilatory changes. Neutrophil influx and increased macrophage inflammatory protein 2 and TNF-\u3b1 levels were found in bronchoalveolar lavage fluid in both TMA- and DNCB-treated mice. The proportion of CD19 + B cells was increased in auricular and cervical lymph nodes of TMA-treated mice. IL-4 and IFN-\u3b3 levels were increased in supernatants of concanavalin A-stimulated auricular and cervical lymph node cells of TMA- or DNCB-treated mice; however, the relative proportions of IL-4 and IFN-\u3b3 levels differed between TMA- and DNCB-treated mice. Serum total IgE levels were increased in TMA-treated mice only. Conclusion: Both compounds induce a mixed T H1-T H2 response, but only TMA induced ventilatory changes. Clinical implications: In the workplace avoiding skin contact with chemical sensitizers might be advised to prevent chemical-induced asthma

Pulmonary exposure to carbon nanotubes promotes murine arterial thrombogenesis via platelet P-selectin

Carbon nanotubes, having a diameter as small as a few nanometers, yet with robust mechanical properties, can be functionalized with chemical and biological agents and be used for the delivery of target DNA molecules or peptides into specific tissues. However, their potential adverse health effects remain unknown. Here, we studied the acute (24 h) effects of intratracheally administered (200 and 400 µg) multi-wall ground carbon nanotubes (CNT) on lung inflammation assessed by bronchoalveolar lavage (BAL), and peripheral arterial thrombogenicity in mice. The latter was evaluated from the extent of photochemically induced thrombosis in the carotid artery, measured via transillumination. I.t. instillation of CNT induced a dose-dependent influx of neutrophils in BAL, paralleled by enhanced experimental arterial thrombus formation. By flow cytometry, circulating platelet-leukocyte conjugates were found to be elevated 6 h after i.t. instillation of CNT. The pretreatment of mice with a blocking anti-P-selectin antibody prevented the formation of platelet conjugates in the circulation but did not affect neutrophil influx in the lung. Although P-selectin neutralization had no effect on the vascular injury triggered thrombus formation in saline-treated mice, it abrogated the CNT induced thrombotic amplification. We conclude that the CNT induced lung inflammation is responsible for systemic platelet activation and subsequent platelet P-selectin mediated thrombogenicity. Our findings uncover that newly engineered CNT affect not only the respiratory but also cardiovascular integrity, necessitating an evaluation of their potential risk for human health

SCCS OPINION ON Colloidal Silver (nano)” - SCCS/1596/18 Preliminary version

The SCCS adopted this document at its plenary meeting on 21/22 February 2018 – 36 pageshttps://ec.europa.eu/health/sites/health/files/scientific_committees/consumer_safety/docs/sccs_o_219.pd

SCCS Opinion on Solubility of Synthetic Amorphous Silica (SAS)

Solubility of Synthetic Amorphous Silica (SAS)Link to opinionhttps://ec.europa.eu/health/sites/health/files/scientific_committees/consumer_safety/docs/sccs_o_228.pdfWG on Cosmetic IngredientsSCCS members: U. Bernauer (Chairperson), L. Bodin, Q. Chaudhry, P.J. Coenraads, M. Dusinska, E. Gaffet (Rapporteur), E. Panteri, Ch. Rousselle, M. Stepnik, S. WijnhovenSCHEER members: P.H.M. Hoet, W.H. de JongSCCS external experts: N. von Götz, A. SimonnardContact: [email protected] request from: European CommissionSCCS Number: SCCS/1606/19Adopted on: 26 February 2019Conclusion of the opinion:1. Does the SCCS consider that Synthetic Amorphous Silica (SAS) are soluble (100 mg/L or higher) or degradable/non-persistent in biological systems, in light of the nanomaterial definition of the Cosmetic Regulation?Having considered the data provided in this dossier and that available in published literature, the SCCS concludes that:i) the solubility values for hydrophilic SAS materials have been reported to range from 22 mg/L to 225 mg/L for the solubility tests performed in aqueous media, or following the enhanced OECD TG 105 (0.5% ethanol). The latter protocol has been noted to increase the solubility by a factor of 10 for some hydrophilic SAS materials.ii) the solubility values of hydrophobic surface-treated SAS materials have been reported to range from 0.4 to 180 mg/L for solubility tests performed in aqueous media, or following a modified enhanced OECD TG 105 protocol (i.e. using 10% ethanol). The latter protocol has been noted to strongly increase the solubility of some hydrophobic SAS materials (by a factor up to 173).The hydrophilic and hydrophobic SAS materials can therefore be regarded as “insoluble” (i.e. below 100 mg/L) to “very slightly soluble” (i.e. 100 mg/L to 1000 mg/L) by the SCCS based upon the terminology used in USP38 and USP 38 NF33 (Table 1 corrected by the SCCS).In regard to the nanomaterial definition in the Cosmetic Regulation, none of the SAS materials (hydrophilic or hydrophobic) included in the dossier can be regarded as soluble. In fact, the Applicant had mistakenly interpreted the SAS materials as soluble on the basis of the solubility of some of the materials being 100 mg/L or higher. The threshold for regarding a material 'soluble' is 33.3 g/L (not 100 mg/L as claimed by the Applicant).No data were provided to help establish whether the SAS materials could be regarded degradable/non-persistent in biological systems.2. Can the SCCS indicate to which kind of Silica this solubility applies?The solubility values reported in the dossier are applicable when SAS materials are subject to the following conditions:- hydrophilic SAS: Silica and hydrated silica when solubilised in aqueous media containing up to 0.5% ethanol,- hydrophobic surface treated SAS: when solubilised in aqueous media containing up to 10% ethanol,- at temperatures between 19.5 to 20.5°C,- with a pH level of between 3 and 8,- over a period between 3 days (hydrophilic SAS) up to 49 days (hydrophobic SAS).3. Does the SCCS have any further scientific concerns with regard to solubility of Synthetic Amorphous Silica (SAS)?- The solubility values considered by the SCCS in this Opinion may not be valid in situations where the SAS materials are formulated/used under conditions that are different from those used in the solubility tests - e.g. when used in a less/non aqueous formulation, or at a different temperature.- In the context of the definition of nanomaterial under the Cosmetics Regulation, which relates to insoluble materials in conjunction with other size/particle related parameters, the question of solubility of a nano-structured material needs to be seen in perspective for use in cosmetics. For nano-structured materials, with the exception of the materials that are completely soluble, it is important to establish whether a proportion of these materials would still exist in undissolved form comprising nanoparticles, at the given use level in a cosmetic formulation.- The SCCS has noted that the protocols used for solubility tests have a strong influence on the solubility of SAS materials.Keywords:SCCS, scientific opinion, Synthetic Amorphous Silica (SAS), solubility, nanomaterials, Regulation 1223/2009Opinion to be cited as:SCCS (Scientific Committee on Consumer Safety), Opinion on solubility of Synthetic Amorphous Silica (SAS), 26 February 2019, SCCS/1606/2019

"SCCS OPINION ON Styrene/Acrylates copolymer (nano) and Sodium styrene/Acrylates copolymer (nano)"SCCS/1595/18 Final

International audienc