London - British scientists have built what they say is the world's first
artificial stomach: a shiny, high-tech box that physically simulates human
digestion.
The artificial gut, designed in Norwich's Institute
of Food Research, is seen during a presentation in Norwich, England,
October 20, 2006. [AP]
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Constructed from sophisticated
plastics and metals able to withstand the corrosive acids and enzymes found in
the human gut, the device may ultimately help in the development of
super-nutrients, such as obesity-fighting foods that could fool the stomach into
thinking it is full.
"There have been lots of jam-jar models of digestion before," said Dr. Martin
Wickham of Norwich's Institute of Food Research, the artificial gut's chief
designer, referring to the beakers of enzymes typically used to approximate the
chemical reactions in the stomach.
Wickham's patented artificial gut is a two-part model that is slightly larger
than a desktop computer. The top half consists of a funnel in which food,
stomach acids and digestive enzymes are mixed. Once this hydration process is
finished, the food gets ground down in a silver metal tube encased in a dark,
transparent box.
Software sets the parameters of the artificial gut -- how long food
remains in a particular part of the stomach, predicted hormone responses at
various stages, and whether it is an infant or adult gut.
Unlike previous gut models, Wickham's model incorporates the physiological
elements of digestion, including the stomach contractions that break up food and
move it along the assembly line of human digestion.
The artificial gut is already attracting commercial attention.
One company wants to use it to test whether a biscuit can release a specific
nutrient in the small intestine. Another group wants to determine if soil
contaminants, which could potentially be swallowed by children playing outside,
get absorbed by the human body.
The model gut's focus on the physical and chemical reactions that take place
in the stomach promises to provide a more detailed understanding of food
structure and its impact on digestion.
"This is an important tool that will allow us to understand what happens in
the gut," said Dr. Peter Ellis, a biochemistry expert at King's College in
London, who was not connected to the project.
Other artificial stomach models have largely neglected the connection between
food structure and digestion, according to Ellis. "This model is important
because it gets the science of digestion right," he said.
By understanding how food gets processed in the gut, and in which part of the
stomach nutrients get absorbed, researchers may be able to develop foods
designed to manipulate the digestive process, a strategy that would have broad
implications for public health.
For instance, knowing how quickly glucose gets absorbed into the bloodstream
could potentially help treat diabetes.
"Our knowledge of what actually happens in the gut is still very
rudimentary," said Wickham, "but we hope that this model can help fill in some
of the blanks."
Some experts say any artificial gut has inherent limitations.
"The stomach is an extraordinarily complex organ, so you cannot create a
model that will undertake all of these functions," said Dr. Stephen Bloom, head
of metabolic medicine at Imperial College in London, who was not involved in the
project.
Still, Bloom said that looking at issues such as the breakdown of food and
the role of enzymes in a model stomach is valuable.
"There are a number of questions that are very difficult to study in real
life that could more easily be answered in the laboratory," he said, noting that
using human volunteers to collect information about digestion is usually a
costly and uncomfortable process.
With a capacity about half the size of an actual stomach, the artificial gut
can "eat" roughly 24 ounces of food. To date, the most substantial meal it's
enjoyed is vegetable soup.
"It's so realistic that it can even vomit," adds Wickham.
The model gut, which was funded by the British government, was built at a
cost of approximately $1.8 million. Wickham and his colleagues are currently
negotiating with about a dozen companies regarding future projects for the
gut.