Biobank@VITO: Biobanking the General Population in Flanders.

During the last 15 years, VITO has established an infrastructure for biobanking a collection of biological samples from the general population in Flanders (Belgium). This biobank was set up to contribute to future, yet unspecified, research questions in the field of environment and health. Biobank@VITO is a population biobank in which bio-specimen including human peripheral blood, cord blood, and blood derivatives (e.

Toxicity of Urban PM and Relation with Tracers of Biomass Burning.

The chemical composition of particles varies with space and time and depends on emission sources, atmospheric chemistry and weather conditions. Evidence suggesting that particles differ in toxicity depending on their chemical composition is growing. This in vitro study investigated the biological effects of PM in relation to PM-associated chemicals.

Assessment of estrogenic and androgenic activity in PM10 air samples from an urban, industrial and rural area in Flanders (Belgium) using the CALUX bioassay.

Background: Endocrine disrupting chemicals represent a broad class of compounds, are widespread in the environment and can pose severe health effects.

Objectives: The objective of this study was to investigate and compare the overall estrogen and androgen activating potential of PM10 air samples at an urban, rural and industrial location in Flanders, using a human in vitro cell bioassay.

Methods: PM10 samples were collected on glass fiber filters every six days between April 2013 and January 2014 using a high-volume sampler.

Identification of PM10 characteristics involved in cellular responses in human bronchial epithelial cells (Beas-2B).

Notwithstanding evidence is present that physicochemical characteristics of ambient particles attribute to adverse health effects, there is still some lack of understanding in this complex relationship. At this moment it is not clear which properties (such as particle size, chemical composition) or sources of the particles are most relevant for health effects. This study investigates the in vitro toxicity of PM10 in relation to PM chemical composition, black carbon (BC), endotoxin content and oxidative potential (OP).

Gene expressions changes in bronchial epithelial cells: markers for respiratory sensitizers and exploration of the NRF2 pathway.

For the classification of respiratory sensitizing chemicals, no validated in vivo nor in vitro tests are currently available. In this study, we evaluated whether respiratory sensitizers trigger specific signals in human bronchial epithelial (BEAS-2B) cells at the level of the transcriptome. The cells were exposed during 6, 10, and 24h to 4 respiratory sensitizers and 6 non-respiratory sensitizers (3 skin sensitizers and 3 respiratory irritants) at a concentration inducing 20% cell viability loss after 24h.

Chemical sensitization and allergotoxicology.

Chemical sensitization remains an important environmental and occupational health issue. A wide range of substances have been shown to possess the ability to induce skin sensitization or respiratory sensitization. As a consequence, there is a need to have appropriate methods to identify sensitizing agents.

Respiratory sensitization: advances in assessing the risk of respiratory inflammation and irritation.

Respiratory sensitization provides a case study for a new approach to chemical safety evaluation, as the prevalence of respiratory sensitization has increased considerably over the last decades, but animal and/or human experimental/predictive models are not currently available. Therefore, the goal of a working group was to design a road map to develop an ASAT approach for respiratory sensitisers. This approach should aim at (i) creating a database on respiratory functional biology and toxicology, (ii) applying data analyses to understand the multi-dimensional sensitization response, and how this predisposes to respiratory inflammation and irritation, and (iii) building a systems model out of these analyses, adding pharmacokinetic-pharmacodynamic modeling to predict respiratory responses to low levels of sensitisers.

Functionality and specificity of gene markers for skin sensitization in dendritic cells.

Transcriptomic analyses revealed a discriminating gene expression profile in human CD34+ progenitor-derived dendritic cells (DC) after exposure to skin sensitizers versus non-sensitizers. Starting from the differential expression in a small set of genes, a preliminary classification model (VITOSENS®) has been developed to identify chemicals as (non-)sensitizing. The objective of the current study is to gain knowledge on the role of the VITOSENS® markers in the DC maturation process, as well as to investigate their activation by a skin sensitizer versus a non-sensitizing danger molecule.

Application of non-invasive biomarkers in a birth cohort follow-up in relation to respiratory health outcome.

Asthma-related symptoms can manifest in children during the early years, but only some of the children will develop the disease. This feasibility study showed that it is possible to apply non-invasive markers (in urine, exhaled nitric oxide (FENO) and exhaled breath condensate (EBC)) in 3-year-old children, and evaluated the biomarkers in relation to health outcomes and potential modifiers. FENO was correlated with respiratory allergy, and was borderline significantly correlated with wheezing, but not with the asthma predictive index (mAPI).

Brominated flame retardants and perfluorinated chemicals, two groups of persistent contaminants in Belgian human blood and milk.

We assessed the exposure of the Flemish population to brominated flame retardants (BFRs) and perfluorinated compounds (PFCs) by analysis of pooled cord blood, adolescent and adult serum, and human milk. Levels of polybrominated diphenyl ethers (PBDEs) in blood (range 1.6-6.

Gene markers in dendritic cells unravel pieces of the skin sensitization puzzle.

The underlying events of how dendritic cells (DC) are capable of evoking an antigen-specific skin sensitization response are not yet understood. Recently, we revealed a set of genes in human cord blood CD34(+) DC (CD34-DC) that show a discriminating behaviour after skin sensitizing exposure. Based on their differential expression, an in vitro assay was developed to identify chemicals as sensitizing or not.

Assessment of chemical skin-sensitizing potency by an in vitro assay based on human dendritic cells.

The skin-sensitizing potential of chemicals is an important concern for public health and thus a significant end point in the hazard identification process. To determine skin-sensitizing capacity, large research efforts focus on the development of assays, which do not require animals. As such, an in vitro test has previously been developed based on the differential expression of CREM and CCR2 transcripts in CD34(+) progenitor-derived dendritic cells (CD34-DC), which allows to classify chemicals as skin (non-)sensitizing.

Exposure of the Flemish population to brominated flame retardants: model and risk assessment.

Human exposure to brominated flame retardants (BFRs) varies widely throughout the world as it depends on country-related usage, production and legislation of these chemicals. US and UK exposure assessments show very diverse levels and patterns which in turn, are likely to differ from those in background exposed countries such as Belgium, where levels tend to be about an order of magnitude lower. The current study assessed human exposure to BFRs through the indoor and outdoor environment (e.

MUTZ-3-derived dendritic cells as an in vitro alternative model to CD34+ progenitor-derived dendritic cells for testing of chemical sensitizers.

The cytokine-dependent CD34(+) human acute myeloid leukaemia cell line MUTZ-3 was used to generate immature dendritic-like cells (MUTZ-3 DC) and their validity as an alternative to primary CD34(+) progenitor-derived DC (CD34-DC) for testing chemical-induced sensitization was assessed. Expression levels of the DC maturation markers HLA-DR, CD86, CD83 and CD11c were studied using flow cytometry after 24 and 48 h exposure to the model compound nickel sulphate (100 and 300 microM). No maturation of MUTZ-3 DC was observed, whereas significantly upregulated expression levels of CD83 and CD86 were noticed in CD34-DC after 24h treatment with 300 microM nickel sulphate compared to control cells.

Gene profiles of THP-1 macrophages after in vitro exposure to respiratory (non-)sensitizing chemicals: identification of discriminating genetic markers and pathway analysis.

It is recognized that respiratory sensitization is a hazard of high concern. Despite international regulatory requirements there is no established protocol for the identification of chemical respiratory sensitizers. New tests should be based on mechanistic understanding and should be preferentially restricted to in vitro assays.

THP-1 monocytes but not macrophages as a potential alternative for CD34+ dendritic cells to identify chemical skin sensitizers.

Early detection of the sensitizing potential of chemicals is an emerging issue for chemical, pharmaceutical and cosmetic industries. In our institute, an in vitro classification model for prediction of chemical-induced skin sensitization based on gene expression signatures in human CD34+ progenitor-derived dendritic cells (DC) has been developed. This primary cell model is able to closely mimic the induction phase of sensitization by Langerhans cells in the skin, but it has drawbacks, such as the availability of cord blood.

Gene profiles of a human alveolar epithelial cell line after in vitro exposure to respiratory (non-)sensitizing chemicals: identification of discriminating genetic markers and pathway analysis.

There are currently no accepted biological prediction models for assessing the potential of a substance to cause respiratory sensitization. New tests should be based on mechanistic understanding and should be preferentially restricted to in vitro assays. The major goal of this study was to investigate the alterations in gene expression of human alveolar epithelial (A549) cells after exposure to respiratory sensitizing and non-respiratory sensitizing chemicals, and to identify genes that are able to discriminate between both groups of chemicals.

Gene profiles of a human bronchial epithelial cell line after in vitro exposure to respiratory (non-)sensitizing chemicals: identification of discriminating genetic markers and pathway analysis.

Respiratory sensitization is a concern for occupational and environmental health in consumer product development. Despite international regulatory requirements there is no established protocol for the identification of chemical respiratory sensitizers. New tests should be based on mechanistic understanding and should be preferentially restricted to in vitro assays.

A cell-based in vitro alternative to identify skin sensitizers by gene expression.

The ethical and economic burden associated with animal testing for assessment of skin sensitization has triggered intensive research effort towards development and validation of alternative methods. In addition, new legislation on the registration and use of cosmetics and chemicals promote the use of suitable alternatives for hazard assessment. Our previous studies demonstrated that human CD34(+) progenitor-derived dendritic cells from cord blood express specific gene profiles upon exposure to low molecular weight sensitizing chemicals.

The allergic cascade: review of the most important molecules in the asthmatic lung.

Asthma is the most common chronic inflammatory disorder of the airways among children. It is a complex clinical disease characterized by airway obstruction, airway inflammation and airway hyperresponsiveness to a variety of stimuli. The development of allergic asthma exists of three phases, namely the induction phase, the early-phase asthmatic reaction (EAR) and the late-phase asthmatic reaction (LAR).

Microarray analyses in dendritic cells reveal potential biomarkers for chemical-induced skin sensitization.

The assessment of the skin sensitising capacity of chemicals is up to now investigated using in vivo animal tests. However there has been an increasing public and governmental concern regarding the use of animals for chemical screening. This has raised the need for the development of validated in vitro alternatives.

Gene expression signatures in CD34+-progenitor-derived dendritic cells exposed to the chemical contact allergen nickel sulfate.

The detection of the sensitizing potential of chemicals is of great importance to industry. A promising in vitro alternative to the currently applied animal assays for sensitization testing makes use of dendritic cells (DCs) that have the capability to process and present antigens to naive T cells and induce their proliferation. Here, we studied changes in gene expression profiles after exposing DCs to the contact allergen nickel sulfate.

Capacity of CD34+ progenitor-derived dendritic cells to distinguish between sensitizers and irritants.

In an attempt to develop an in vitro test to identify contact sensitizers, mostly dendritic cells (DCs) derived from monocytes (Mo-DC) have been used. Less is known about the potency of DC derived from CD34+ progenitors (CD34-DC) for in vitro allergen testing. CD34+ progenitor derived DC were exposed to nine well-known allergens (one weak, three moderate and five strong allergens) and two irritants.

Cytokine transcript profiling in CD34+-progenitor derived dendritic cells exposed to contact allergens and irritants.

We here investigated wether genes encoding the interleukins IL-1beta, IL-6 and IL-8, and the chemokines CCL2, CCL3, CCL3L1 and CCL4 are useful markers for sensitization testing in CD34+-progenitor derived dendritic cells (CD34-DC). CD34-DC from at least three donors were exposed during 0.5 up to 24h to the chemical sensitizers nickel sulphate, oxazolone, 2,4-dinitrochlorobenzene (DNCB) and eugenol, and to the irritants sodium dodecyl sulphate (SDS) and benzalkonium sulphate (BC).

Limited effect of selected organic pollutants on cytokine production by peripheral blood leukocytes.

To test the hypothesis that some persistent organic pollutants contribute to the increased prevalence of allergic disease, the effects of selected compounds on cytokine production by PBMC from control and allergic donors were evaluated. Cells were cultured for six days in the presence of a xenobiotic (PCB 153, hexachlorobenzene, pentachlorobenzene, pentachlorophenol, lindane, atrazine or DMSO vehicle) with phytohemagglutinin (PHA) or Dermatophagoides pteronyssinus extract, then for one day in the presence of PHA + phorbol 12-myristate 13-acetate. PCB 153 reduced the levels of IL-10, IFN-gamma and TNF-alpha.