Celiac disease is an autoimmune disorder characterized by an inflammatory response to eating gluten. An estimated 1 percent of people worldwide have celiac disease, but diagnosing the condition is difficult, often due to vague, seemingly minor, or even absent symptoms. Consequently, the epidemiology of celiac disease is best described by the “iceberg model.” That is, for every diagnosed case of celiac disease (the visible part of the iceberg), roughly five cases remain undiagnosed (the hidden part of the iceberg). Findings from a new study indicate that enzymes from Rothia bacteria may be useful in treating people who have celiac disease.
Gluten is a composite of two proteins found in wheat, barley, and rye. During normal digestion, enzymes break proteins down into groups of amino acids called peptides. Most peptides can be broken down further, taken up in the intestine, and then transported to the body’s tissues for use. However, gluten cannot be broken down by the digestive enzymes and can provoke an immune response in susceptible people, causing celiac disease.
Rothia bacteria are regular inhabitants of the mouth and respiratory tract. They rarely cause infections, except in some immunocompromised people. Rothia bacteria can break down the peptides in gluten that provoke the immune response.
The authors of the study extracted subtilisins, a type of enzyme found in the membrane of Rothia bacteria, and monitored the enzymes' activity. They also monitored the activity of food-grade subtilisins, enzymes used to make natto, a fermented soybean product. They found that both types of bacterial subtilisins effectively broke down the immunogenic peptides present in gluten, demonstrating that subtilisins from Rothia bacteria or other food-grade bacteria might be useful in treating celiac disease.