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What mode of action do nanomaterials have in liver and intestine?

(Nanowerk News) What mode of action do nanomaterials ingested via food have in liver and intestine? Which factors determine their toxicity? Due to the large number of different nanomaterials, it is hardly possible to test every one for its toxic properties. For this reason, specific properties for the classification of nanomaterials are to be examined within the scope of the Franco-German research project "SolNanoTox", which began on 1 March 2014. The Federal Institute for Risk Assessment (BfR) requires data on bioavailability for its assessment work, in particular on whether the solubility of nanomaterials has an influence on uptake and accumulation in certain organs, such as liver and intestine. "We want to find out in our tests whether the criterion ‘soluble or insoluble’ is a determining factor for uptake and toxicity of nanomaterials," says BfR President Professor Dr. Dr. Andreas Hensel.
A risk assessment of nanomaterials is hardly possible at the moment and involves a very high degree of uncertainty, as important toxicological data on their behaviour in tissue and cells are still missing. The German-French SolNanoTox research project examines which role the solubility of nanomaterials plays with regard to their accumulation and potential toxic properties. The project is to run for three and a half years during which the BfR will work closely with its French sister organisation ANSES. Other partners are the Institut des Sciences Chimiques de Rennes and Universität Leipzig. The German Research Foundation and French Agence Nationale de la Recherche (ANR) are funding the project.
The tasks of the BfR include in vitro tests (e.g. the investigation of the influence of the human gastrointestinal system) and analysis of biological samples with regard to the possible accumulation of nanomaterials. In addition to this, the BfR uses modern methods of mass spectrometry imaging to find out whether nanoparticles alter the structure of biomolecules, e.g. the structure of the lipids of the cellular membrane. So far, these important tests, which are necessary for assessing possible changes in DNA or cellular structures caused by nanomaterials in food, have not been conducted.
In the project, two fundamentally different types of nanoparticles are examined as representatives for others of their type: titanium dioxide as representative of water insoluble nanoparticles and aluminium as an example of nanomaterials which show a certain degree of water solubility after oxidation. It is examined whether the degree of solubility influences the distribution of the nanomaterials in the body and whether soluble materials may possibly accumulate more in other organs than insoluble ones. The object is to establish whether there is a direct toxic effect of insoluble nanomaterials in general after oral uptake due to their small size.
Different innovative analytical methods are combined in the project with the aim to elucidate the behaviour of nanomaterials in tissue and their uptake into the cell. The main focus is on effects which can trigger genotoxic damage and inflammation. At first, the effects of both materials are examined in human cultures of intestinal and liver cells in an artificial environment (in vitro). In the following, it has to be verified by animal experimentation whether the observed effects can also occur in humans. This modus operandi allows to draw conclusions on effects and mode of action of orally ingested nanomaterials with different properties. The goal is to group nanomaterials on the basis of specific properties and to allocate the corresponding toxicological properties to these groups. Motivation for the project is the enormous number of nanomaterials with large differences in physicochemical properties. Toxicological tests cannot be conducted for all materials.
Source: Federal Institute for Risk Assessment (BfR)
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