Insulin produced in genetically modified plants

NEW YORK (Reuters Health) - U.S. researchers have successfully expressed the precursor protein of insulin in lettuce and tobacco plants. Moreover, feeding these genetically modified plants to mice that have a tendency to become diabetic protected the animals against inflammation of the pancreas.

Generating the proinsulin protein in plants is a low-cost alternative to standard production methods, Dr. Henry Daniell, from the University of Central Florida in Orlando, and colleagues note in their report in the Plant Biotechnology Journal.

In the study, the scientists describe the creation of lettuce and tobacco chloroplast lines that produce a fusion protein consisting of a subunit of cholera toxin joined to human proinsulin.

Giving powered tobacco leaf to diabetic mice helped preserve insulin-producing beta-cells in the pancreas, Daniell's team reports, and this was associated with lower levels of glucose in their blood and urine.

Due to the stigma associated with tobacco, the researchers have now moved on to using genetically engineered lettuce instead. They add that in light of the encouraging results in animals, testing in humans is now underway.

SOURCE: Plant Biotechnology Journal, July 2007.