Celiac disease sufferers, take heart: your exile from the realm of wheat and barley may not be lifelong. Scientists are working on creating strains of grains that won't provoke symptoms in celiac patients, meaning that soon the condition won't mean a life sentence to a gluten-free diet.
Gluten, which is found in wheat, barley, rye and other grains, stirs up the immune systems of people with celiac disease. The immune overreaction damages the inner surfaces of the person's small intestine, which prevents them from absorbing nutrients properly. A celiac disease sufferer gets much less nourishment, regardless of how much they eat.
It's unclear just how celiac disease arises, and it can crop up at any point in life. At the moment, the only successful treatment available to patients is lifelong abstinence from gluten. This kind of rigid, lifestyle-altering treatment works, but is hard to adhere to and can have unintended consequences -- some studies show that a gluten-free diet alters the composition of bacteria in a person's gut for the worse.
Gluten is made of a lot of different proteins called prolamins. The primary celiac disease trigger in wheat is a kind of gluten protein called gliadin, but celiac patients can be sensitive to other types as well.
In a paper published on Monday in the Proceedings of the National Academy of Sciences, a team of researchers led by Washington State University scientists explored the possibility of creating a general therapy for celiac disease by genetically altering wheat so as to remove all of the offending gluten proteins, while still retaining those non-offensive gluten proteins that are needed to bake good bread. Without any gluten, bread dough would be inelastic.
The researchers focused on a gene in wheat called DEMETER, or DME. This gene makes an enzyme that activates other genes that lead to the development of the gluten proteins that provoke an immune reaction in celiac disease patients.
Using a genetic engineering technique called RNA interference, the scientists targeted DME with molecules aimed at silencing the gene, hoping this would have a downstream effect of eliminating the undesirable gluten proteins.
The results looked good: in 20 experimental plants, DME activity was tamped down more than 85 percent, and the amount of immune system-provoking gluten proteins decreased by more than 76 percent.
Of course, the authors acknowledge this is only the first step – the technique has to be tested again to make sure that it works, and refined even further to try and totally eliminate immunogenic gluten proteins. Then the new varieties of wheat have to be tried out on laboratory animals, and then small trials of human patients, before they can be labeled for consumption by people with celiac disease.
Nevertheless, the work demonstrates “the possibility of developing wheat varieties compatible for … celiac patients,” the authors wrote.
SOURCE: Wen et al. “Structural genes of wheat and barley 5-methylcytosine DNA glycosylases and their potential applications for human health.” PNAS published online 26 November 2012.
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