Toxicology research for approving new products for the market can take place more quickly and efficiently by largely replacing laboratory animal testing with a combination of in-vitro research and computer models said Prof. Ruud Woutersen. Modification of test protocols will lead to a significant increase in the reliability of the results of toxicological tests and consequently to a better evaluation of the risks of toxic substances, said Prof. Rolaf van Leeuwen. Woutersen and Van Leeuwen are toxicologists at Wageningen University, Netherlands.
Prof. Van Leeuwen and Prof. Woutersen were recently appointed Professor by Special Appointment to the Sub-department of Toxicology at Wageningen University. The expertise of both professors lies primarily in the combination of knowledge about the practice of toxicology, legislation, regulations, national and international policy and the implementation and acceptance of innovative toxicological test methods in practice.
Ruud Woutersen, whose teaching and research remit is Translational toxicology, will focus on developing expertise and methodologies on the potential hazards of substances, while Rolaf van Leeuwen, whose teaching and research remit is the Integral risk evaluation of toxic components in food, will focus on the risks people incur from exposure to hazardous substances.
Is it possible to assure the safety of people who are exposed to a chemical substance, a new food ingredient or a new medicine without this product being tested for safety using laboratory animals? For the time being, this question must be answered in the negative. But the process can be more efficient and require less animal testing, according to Professor Woutersen in his inaugural address Translationele toxicologie: de mens als proefdier? (Translational toxicology: people as laboratory animals?) He argued in favour of a research strategy where animal testing is used only in the final stage of research. In the stages before this, researchers can work with computer models or with in-vitro research, preferably with human material such as isolated organs, tissues or cells.
Woutersen argued for the more rapid development, validation and acceptance of innovative methods. It currently takes years or decades before innovative methods are introduced. In view of the pressure on toxicologists to test new substances, this is an impossible situation. Woutersen also called for a change in the perspective on uncertainty: we must move away from reducing the uncertainty regarding only a few substances and focus on reducing the overall uncertainty. This means that we must accept some degree of uncertainty.
In his inaugural address, Risico’s op de toxicologische snelweg (Risks on the toxicological motorway), Prof. Van Leeuwen called for the implementation of the so-called benchmark method at the international level. This method was developed in the USA to obtain a more precise estimate of the dosage at which a harmful effect can occur. With this method it is possible to make much more reliable predictions for all kinds of hazardous substances about the dosage at which a specific effect will occur, and to indicate the probability that such an effect will occur. This means that a much more reliable evaluation can be made about the potential risks. Van Leeuwen wondered why this method was not implemented long ago; the only reason that he could think of is that the mathematical models on which it is based are complicated and difficult for the risk evaluators to understand.
Van Leeuwen explained that the concept of DALY (Disability Adjusted Life Years), which was developed in nutritional research as an indicator of overall disease burden in a population expressed as the total number of life years lost to premature death and the total number of healthy life years lost to disablement by disease, can also be used in toxicological risk evaluation. For example, this concept can be used in risk-benefit evaluation, where health-promoting effects are weighed against health-threatening effects. Van Leeuwen said that he wants to use this method especially as part of research into the safety and effectiveness of nutritional supplements.
Prof. Rolaf van Leeuwen (1946) is employed as a Food Safety Toxicologist at the National Institute for Public Health and the Environment (RIVM) in Bilthoven. Prof. Ruud Woutersen (1950) is substitute head of the Department of Toxicology and Applied Pharmacology at TNO Quality of Life in Zeist.