In vitro immunotoxicity of bis(tri-n-butyltin)oxide (TBTO) studied by toxicogenomics

The biocide and environmental pollutant bis(tri-n-butyltin)oxide (TBTO) causes thymus atrophy in rodents. Whether the depletion of thymic lymphocytes by tributyltin compounds may be the result of inhibition of cell proliferation or induction of apoptosis is subject of debate. We examined gene expression profiles in primary rat thymocytes exposed to TBTO in vitro at dose levels of 0, 0.1, 0.3, 0.5, and 1.0muM. By measuring cell viability and apoptosis, exposure conditions were selected that would provide information on changes in gene expression preceding or accompanying functional effects of TBTO. Several processes related to TBTO-induced toxicity were detected at the transcriptome level. Effects on lipid metabolisms appeared to be the first indication of disruption of cellular function. Many transcriptional effects of TBTO at higher dose levels were related to apoptotic processes, which corresponded to present or subsequent thymocyte apoptosis observed phenotypically. The gene expression profile was, however, not unambiguous since expression of apoptosis-related genes was both increased and decreased. Stimulation of glucocorticoid receptor signaling appeared to be a relevant underlying mechanism of action. These findings suggest that TBTO exerts its toxic effects on the thymus primarily by affecting apoptotic processes, but the possibility is discussed that this may in fact represent an early effect that precedes inhibition of cell proliferation. At the highest dose level tested, TBTO additionally repressed mitochondrial function and immune cell activation. Our in vitro toxicogenomics approach thus identified several cellular and molecular targets of TBTO that may mediate the toxicity towards thymocytes and thereby its immunosuppressive effects. AD - Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Department of Health Risk Analysis and Toxicology (GRAT), Maastricht University, Maastricht, The Netherlands; National Institute of Public Health and the Environment (RIVM), Laboratory for Toxicology, Pathology and Genetics (TOX), Bilthoven, The Netherlands

Cytotoxicity and mutagenic activity of moulds colonizing building materials

Materiały konferencyjne zostały wydane jako numer specjalny czasopisma "Ochrona przed Korozją - 9s/A/2006".Badania obejmowały analizę mikologiczną oraz toksykologiczną ekstraktów z przegród budowlanych porażonych pleśniami (wykrywanie obecności mikotoksyn, ocena aktywności cytotoksycznej i mutagennej). Stwierdzono, że pleśnie na przegrodach budowlanych nie wytwarzały mikotoksyn mimo aktywnego wzrostu. Badane ekstrakty nie wykazywały również efektu cytotoksycznego ani mutagennego. Cecha toksynotwórczości ujawniła się dopiero w warunkach laboratoryjnych po hodowli na pożywce mikrobiologicznej YES oraz na materiałach budowlanych w warunkach kontrolowanej wilgotności z dodatkiem kurzu. Brak tworzenia mykotoksyn w warunkach budynku może być spowodowane obecnością innej towarzyszącej mikroflory. Stwierdzono, iż cytotoksyczność prób na materiałach celulozowych (drewno, płyta gipsowo-kartonowa, tapeta) wynika z obecności wytworzonej przez A.ochraceus ochratoksyny A. Ekstrakty z wykładziny dywanowej wykazywały właściwości cytotoksyczne chociaż nie wykryto w nich ochratoksyny A, co może wskazywać na obecność innych metabolitów. Spadek żywotności mysich fibroblastów 3T3-L 1 narażanych na ekstrakty z cementu i skóry spowodowany był najprawdopodobniej właściwościami chemicznymi tych materiałów.Mycological analysis, toxicological analysis of mouldy dwellings partitions (mycotoxins presence analysis, cytotoxicity and mutagenie activity of mouldy extracts from buildings partitions) were investigated. lt has been found that moulds didn 't produce mycotoxins on buildings partitions, in spite active growth of these. Mouldy extracts weren't cytotoxicity and mutagenie. Toxicity of moulds has appeared in laboratory condition after growth on microbial medium YES and after cultivation on buildings materials with controlled humidity and addition of dust. It has been found that cytotoxicity of mouldy cellulolitic materials (wood, carton-board plate, wallpaper) was resulted of ochratoxin A production by A.ochraceus. Extracts from mouldy carpet lining were cytotoxicity, but didn 't detect ochratoxin A, it has been showed on presence of another metabolites produced by moulds. The reduce of vitality mouse fibroblast 3T3-Ll after exposition to extracts from cement and leather was caused by chemical compounds property of these

Development of the "Cell Chip": a new in vitro alternative technique for immunotoxicity testing

Predictive testing of immunotoxicity associated with chemical compounds is complicated and cannot be accomplished with a single test. As most of the existing tests for immunotoxicity employ experimental animals, there is an increasing need for alternative tests in vitro. We have developed a new system for in vitro immunotoxicity testing, which employs changes in cytokine expression observed in vitro as an endpoint indicating potential for perturbation of the immune system in vivo. This system named "fluorescent cell chip" (FCC) is based on a number of genetically modified cell lines that regulate the expression of a transgene coding for fluorescent protein enhanced green fluorescent protein (EGFP) in a similar way as they regulate expression of IL-1beta, IL-2, IL-4, IFN-gamma, IL-10, TNF-alpha, and beta-actin. Morphological and functional features of selected cell lines expressing EGFP under the control of cytokine promotors were compared with maternal cell lines and this comparison showed that critical functional features of the maternal cell lines were preserved in EGFP expressing cells. Two chemicals with known immunotoxic activities, cyclosporine A and potassium tetrachloro-platinate(II), mediated compound-specific pattern of inhibition and activation of reporter gene expression. Thus, the "fluorescent cell chip" has demonstrated potential for application as a predictive screening test for immunomodulatory activities of chemicals. The major advantage of this approach is the possibility to apply this test in high throughput screening of high number of compounds for their well defined biological activit

Detection of immunotoxicity using T-cell based cytokine reporter cell lines ("Cell Chip")

Safety assessment of chemicals and drugs is an important regulatory issue. The evaluation of potential adverse effects of compounds on the immune system depends today on animal experiments. An increasing demand, however, exists for in vitro alternatives. Cytokine measurement is a promising tool to evaluate chemical exposure effects on the immune system. Fortunately, this type of measurement can be performed in conjunction with in vitro exposure models. We have taken these considerations as the starting point to develop an in vitro method to efficiently screen compounds for potential immunotoxicity. The T-cell lymphoma cell line EL-4 was transfected with the regulatory sequences of interleukin (IL)-2, IL-4, IL-10, interferon (IFN)-gamma or actin fused to the gene for enhanced green fluorescent protein (EGFP) in either a stabile or a destabilised form. Consequently, changes in fluorescence intensity represent changes in cytokine expression with one cell line per cytokine. We used this prototype "Cell Chip" to test, by means of flow cytometry, the immunomodulatory potential of 13 substances and were able to detect changes in cytokine expression in 12 cases (successful for cyclosporine, rapamycin, pentamidine, thalidomide, bis(tri-n-butyltin)oxide, house dust mite allergen (Der p I), 1-chloro-2,4-dinitrobenzene, benzocaine, tolylene 2,4-diisocyanate, potassium tetrachloroplatinate, sodium dodecyl sulphate and mercuric chloride; unsuccessful for penicillin G). In conclusion, this approach seems promising for in vitro screening for potential immunotoxicity, especially when additional cell lines besides T-cells are included

Hypertension among older adults in low- and middle-income countries:prevalence, awareness and control

This study uses data from the World Health Organization's Study on Global Ageing and Adult Health (SAGE) to examine patterns of hypertension prevalence, awareness, treatment and control for people aged 50 years and over in China, Ghana, India, Mexico, the Russian Federation and South Africa