PROJECT DESCRIPTION
BACKGROUND
Thousands of man-made chemicals have been released into the environment in vast quantities since the chemical industry began to boom in the 1950's. Humans and wildlife are exposed to these chemicals through their nutrition, the air, the water and even through the placenta during foetal development. A range of these substances, which are designed for use in industry, agriculture and consumer products are suspected of interfering with the endocrine systems of humans and wildlife at concentrations far below the so called "No Observed Adverse Effect Levels" (toxicology) and of causing adverse health effects such as cancer and reproductive abnormalities. For human beings they are held responsible for e.g. the decline in sperm quality and the increase in testicular cancer and female breast cancer in several countries worldwide. These substances are known as endocrine disrupters (sometimes also referred to as xenostrogens).
OBJECTIVES
The project had a double objective: - Given the lack of available knowledge on these compounds (type of interaction with hormonal system, persistence in the environment, exposure considerations), the first objective of the project was to develop adequate, reliable and relevant assays for the detection and quantification of endocrine disrupters. - Even if the use of several of those compounds is reduced in the coming years, many of them will continue to persist in our environment for decades due to their low biodegradability and important bioaccumulation. This makes the development of systems preventing ingestion of those compounds more than necessary. Therefore the second objective of the project was to reduce human exposure to endocrine disrupters either by developing a water filter or by using probiotic “health food” to prevent intestinal uptake out of the ingested food. The project focussed on the most important compounds in detergents (nonyl, octylphenol), some pesticides (atrazine and metabolites), some PCB's and plastifiers (Phthalates: BBP, DBP).
RESULTS
Three “in vitro” assays have been tested and validated, with a particular focus on male sterility, which represents a significant advance in this field. It is important to outline the advantages of “in vitro” assays in comparison with “in vivo” assay in terms of costs, complexity, interpretation of results and ethical considerations. Using nurse cells of spermatogenesis, it was possible to study the effects of estrogens on the production of one of the most important proteins (inhibin B) involved in the feedback system regulating male fertility. For reasons of animal welfare and experimental reproducibility and sensitivity, the use of immortile Sertoli cells in the development of an estrogen bioassay with a high relevance for male fertility was explored. In the search for tools to reduce involuntary human exposure to estrogenic compounds, the project investigated the use of estrogen receptors to extract compounds from water using the same selective mechanisms by which they exert their biological function in the body. Several estrogen receptors were successfully cloned and their binding capacity determined. However although it was seen that the receptors could be used in laboratory, the project came to the conclusion that the proteins were too unstable to be applied in a household purification system. The experimental protocol was then modified in order to develop a bio-extraction module for the elimination of estrogenic compounds using catalytic manganese dioxide particles. The results were promising but further experiments are needed to investigate and optimise the estrogen removal efficiency. Finally the hypothesis that the uptake of certain endocrine disrupters via the gastro-intestinal tract in the body could be prevented by the presence of certain strains of Lactobacilli was investigated. These strains were tested for their capacity of adsorbing model compounds in a gastro-intestinal simulator (SHIME). Three “in vitro” assays have been tested and validated, with a particular focus on male sterility, which represents a significant advance in this field. It is important to outline the advantages of “in vitro” assays in comparison with “in vivo” assay in terms of costs, complexity, interpretation of results and ethical considerations. Using nurse cells of spermatogenesis, it was possible to study the effects of estrogens on the production of one of the most important proteins (inhibin B) involved in the feedback system regulating male fertility. For reasons of animal welfare and experimental reproducibility and sensitivity, the use of immortile Sertoli cells in the development of an estrogen bioassay with a high relevance for male fertility was explored. In the search for tools to reduce involuntary human exposure to estrogenic compounds, the project investigated the use of estrogen receptors to extract compounds from water using the same selective mechanisms by which they exert their biological function in the body. Several estrogen receptors were successfully cloned and their binding capacity determined. However although it was seen that the receptors could be used in laboratory, the project came to the conclusion that the proteins were too unstable to be applied in a household purification system. The experimental protocol was then modified in order to develop a bio-extraction module for the elimination of estrogenic compounds using catalytic manganese dioxide particles. The results were promising but further experiments are needed to investigate and optimise the estrogen removal efficiency. Finally the hypothesis that the uptake of certain endocrine disrupters via the gastro-intestinal tract in the body could be prevented by the presence of certain strains of Lactobacilli was investigated. These strains were tested for their capacity of adsorbing model compounds in a gastro-intestinal simulator (SHIME).
