Researchers have found a technique which has already revealed that the chemical substance DDT had uncharted effects on humans, who for instance may develop asthma. The software also renders superfluous the use of tens of thousands of laboratory animals when initiating studies of a substance. (Photo: Colourbox).

Now we can learn more about chemicals in the body

Now it will be much easier to examine the effects of chemical substances on humans, thanks to a new computer model which compares data from all over the world.

The US National Research Council and the European Chemicals Agency have long been searching for new ways to study the effects of chemical substances on humans. What is needed are faster and more effective tests, and an alternative to costly animal experiments would make the process cheaper as well as saving the lives of thousands of laboratory animals.

Two Danish researchers have now come up with a more efficient, less costly way of testing for chemical substances and their method has just been published in the journal Environmental Health Perspectives.

Karine Audouze, PhD, a lecturer at Denmark's Technical University (DTU), and Professor Philippe Grandjean from the Department of Health Service Research at the University of Southern Denmark (SDU) have developed and tested a computer program which compares existing chemical data to give an indication of how the body reacts to a toxic substance.

A smart collection of existing knowledge

On the Internet there are now many international, publicly accessible databases compiled by universities or laboratories, containing information about the properties of chemicals and their effects on human genes as well as their correlation with various diseases. Apart from listing chemicals by name, the databases also provide information including synonyms for the chemicals, their chemical structures and potential health risks.

The two researchers have combined these databases into a new database called ChemProt, which was developed at DTU. ChemProt links up all the information and assesses a given chemical’s effects on, and bonds with, the body's proteins and in this way predicts possible health risks.

The result is a computer model which can predict chemicals' toxicological consequences to humans. The name of the chemical is entered into a search box, after which it is compared to, and listed against, all the available data.

Helps researchers find a specific focus

According to Professor Grandjean, the computer model can make studies of chemical substances more logical and comprehensive.

"The computer model links all known data together. When you want to examine a chemical, the model can compare it to everything we already know. In this way we can find out how the chemical bonds itself to specific proteins in the body and the likely consequences of this."

The model can exclude a number of scenarios and point to something quite specific, which researchers can then study more closely.

"This goes far beyond traditional animal experiments in which animals are given different doses of a substance so that we can see what happens," says Grandjean.    

Test showed correlation between DDT and autism

In order to examine the usefulness of their invention, the researchers used ChemProt to examine the chemical substance DDT (dichlorodiphenytrichloroethane).

DDT was once regarded as a miracle substance as it proved to be extremely effective as an insecticide. However, it has since proven highly non-biodegradable and extremely harmful to the environment as well as to humans in the long term. The substance has now been banned throughout most of the world.

Earlier studies of DDT focused to a high degree on breast cancer, semen quality and its harmful effects on the development of the brain. Delving deeper into the researchers’ computer model, however, also revealed links between DDT and the development of diabetes, asthma and autism.

These discoveries have led the researchers to urge closer examination of DDT.

The program could lead to fewer experiments on animals

Although the computer model has demonstrated its effectiveness in the study of chemical substances, it is not a replacement for experiments on animals. The programme will also help to point researchers in the right direction by excluding certain scenarios and making others more probable.

"The computer model should be seen as a more effective method of arousing suspicion. The program can account for some correlations, which researchers and authorities can then pursue. Following this it may naturally be necessary and very useful to carry out experiments on animals. However, by limiting the use of laboratory animals and thus rendering the process more efficient, there is much to be won," says Professor Grandjean.



Read the article in Danish at

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