Models and facilities to study harmful and beneficial effects

The National Food Institute has developed advanced QSAR computer models to predict harmful effects caused by different chemical substances. QSAR is an abbreviation for quantitative structure-activity relationship and is a relationship between the structure of a chemical substance and another given property. This other property may be a physical-chemical property or a biological activity, including the ability to cause a toxic effect.

The models can predict the potentially harmful effects of a chemical substance by looking at whether its structure is similar to that of other substances which have already been tested. Researchers at the institute have built a QSAR database, which contains predictions from more than 200 QSAR models and more than 600,000 organic substances.

The database is publicly available and it is continually expanded as the institute acquires or develops new models. The system behind the QSAR database is described in further detail in the user manual on the database website. More information about the models that are incorporated into the database can also be found in the documentation reports on the website (the so-called QMRFs: QSAR Model Reporting Formats).

If results from laboratory experiments are not available, results from QSAR models can in some cases be used to assess whether a chemical can cause a given effect without the use of further testing. However if results from laboratory experiments are available, results from the institute’s models can be included in an overall assessment of a chemical substance along with information derived from other alternative methods and possibly historical data from animal testing that are not sufficiently robust to stand alone.

The models can also be used to virtually screen and prioritize the chemicals which it is most necessary to investigate further through testing in cells or animals or by other methods. Furthermore the models can help in the selection of safer alternatives that can substitute a substance of concern in order to minimize the risk of later having to perform extensive experimental tests because suspicion arises that the substance has harmful effects.

In this way the National Food Institute has for many years carried out research and developed alternatives to animal testing in order to study the potentially harmful effects of thousands of chemical substances, which in turn has helped companies and authorities save both time and money.

In Vitro methods

Another important part of the National Food Institute’s research into and work on alternatives to animal testing is the use and development of in vitro test methods, which are based on cells or tissue from animals or humans. These cell based test methods can be used to study and assess the harmful effects of chemical substances on humans.

Because a chemical can affect people in many different ways the institute has been focusing on developing a broad range of in vitro tests covering different mechanisms and as such also the different ways in which a substance can affect the body.

The in vitro test methods being used by the National Food Institute are based on cells from both animals and humans. Since laboratory tests based on cells from humans are expected to be better than the current animal testing at predicting effects in humans, part of the institute’s research is focused on developing new in vitro tests based on human cells, such as stem cells.

Animal testing facilities

When computer calculations and in vitro testing alone do not provide enough information, the National Food Institute has also animal testing facilities. These are designed to conduct animal testing that will produce data on harmful or beneficial effects of dietary factors, chemical substances and products, as well as microorganisms, including genetically modified microorganisms.

These tests support the institute’s work on food safety as well as the health effects of chemical substances that people could be exposed to in their everyday life. The animal testing facilities are also used to perform such animal testing for other institutes within the Technical University of Denmark, other research institutes or companies.

The animal testing facilities include a number of ordinary animal rooms with controlled environmental conditions where small laboratory animals such as rats and mice can be housed. Moreover the facility includes isolators where germ-free mice (that are born without any gut bacteria) can be kept and where it is possible to work with particular substances. The institute also has facilities where the researchers can work with behavioural testing system (e.g. to test for learning and memory).