Philosophy of AR > Animal Testing - Index > Anti-Vivisection Index
Artificial gut may replace animal testing

5 December 2006
by Hilary Jones

The most realistic model of the human gut to date could help reduce our reliance on animals for testing new food and drug products, say U.K. researchers.

Image: Institute of Food Research

SYDNEY: The most realistic mechanical and biochemical model of the human gut to date could reduce testing of new drugs and foods on animals and humans, U.K. researchers have said.

"We have developed the model gut so that we can move away from animal studies," said project leader Martin Wickham, of the Institute of Food Research, Norwich. "We can also use the model gut to study compounds that can not be studied in the human volunteer, because they are potentially harmful."

According to the research team, the gut model has many potential applications, including trialling orally-taken drugs, testing new foods and studying diseases of the digestive tract.

The model includes a stomach and a small intestine, with mechanical parts that imitate the muscular breakdown of food and components that mimic biochemical digestive enzymes.

"There is a requirement for dynamic models such as ours, incorporating all the key aspects of digestion, so we can process complex, multiphase foods - in other words, real meals," said Wickham.

Current static models focus on the biochemistry of the gut, not physical digestion or movement between parts of the digestive system, so the models can only be used to process isolated nutrients or very simple foods, said Wickham.

To see the human gut in action, they turned to a form of magnetic resonance imaging (MRI) called echo planar imaging. According to the researchers, echo planar imaging takes images faster than conventional MRI, and is better suited to recording moving objects like stomach muscles or food. The stomach of human volunteers was imaged while actively digesting food, allowing the researchers to model better how the stomach works.

In the new model, the food first goes to the main part of the stomach where it is broken down and mixed by muscle-like action. It then is selectively emptied into a model of the antrum - the lower part of the stomach. There food is further mechanically broken up before being released into a model duodenum, the first part of the small intestine.

The model also includes digestive enzymes, stomach acid, bicarbonates, phospholipids and bile, which in humans help digest food. The enzymes are identical to the ones found in the human gut, but are made by genetically modified organisms such as corn.

"It is the only model developed to combine emerging knowledge of the physical, mechanical and biochemical environments encountered by ingested material during digestion," said Wickham.

According to the team, the gut model could be used to assess the safety of new genetically modified foods, to test foods for their glycaemic index and nutritional uptake, and to screen for the effect of allergenic proteins and environmental contaminants. It could also be used to study how micro-organisms like salmonella, survive in and interact with the digestive system.

Drug delivery technologies such as controlled release systems - currently tested on animals - could be analysed in the model, as could the interaction of drugs with digestive enzymes and meals.

The technology is in the process of being commercialised, therefore details of the model have been kept confidential, but Wickham said they plan to publish data in a scientific journal in the near future.

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