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Posted: Jun 12, 2013
Polymers protect enzymes
(Nanowerk News) The idea of aiding digestion in people who are unable to tolerate or digest certain food ingredients by having them swallow appropriate enzymes seems obvious. Until now, however, such attempts have usually failed due to the conditions in the digestive tract, which have evolved to break down proteins – which also include the helpful enzymes – efficiently into their constituent parts.
Researchers from ETH Zurich now present a promising approach to how therapeutic enzymes can be stabilised in the digestive tract, and thus protected from destruction, in the latest online issue of Nature Chemistry ("Sustained gastrointestinal activity of dendronized polymer–enzyme conjugates"). For the first time, they demonstrated that enzymes attached to polymer chains remain active in the stomach - and partly in the small intestine, too - for considerably longer periods of time than unconjugated enzymes.
Enzymes that last longer
“Without the protection of the polymers, the enzymes in the stomach become inactive within minutes. Enzymes shielded by polymers, however, carry on working for up to three hours,” says Jean-Christophe Leroux, professor of Drug Formulation and Delivery at the Institute of Pharmaceutical Sciences and head of the research project.
The researchers experimented with various common polymers. Enzymes armed with a polymer developed by the group headed by A. Dieter Schlüter, professor of Polymer Chemistry at the Department of Materials, remained active the longest. Exactly why this polymer works so well is still unclear. However, they did discover one peculiarity: “This polymer adheres particularly well to the mucous membrane the stomach or intestinal wall is lined with,” explains Leroux. As a result, the enzyme remains longer at its place of action.
Possible use for coeliac disease
Although these initial in vivo experiments conducted on rats only equate to basic research and we are still a far cry from trials with human subjects, the researchers’ results are promising. “Using this method, therapeutic enzymes in the digestion system could actually be stabilised in the future,” says Leroux. This would enable the treatment of various diseases, for some of which there are no treatment possibilities as of yet.
Leroux sees one possible use in coeliac disease. In those affected, gluten, a protein contained for instance in wheat foods, can trigger inflammation of the bowel and sometimes lead to severe secondary complications. Today, people affected only have the option of keeping to a strictly gluten-free diet. Making use of the new method, however, patients could simple take enzymes with food, which make quick work of the gluten in their diet that is so harmful to them.