Researchers are evaluating the feasibility of using a pill to prevent common calcium oxalate kidney stones. They are trying to determine whether kidney stones can be prevented in laboratory rats by giving them a coated pill to replenish a beneficial bacterium called Oxalobacter formigenes. An absence of this intestinal bacterium has been linked to the development of calcium oxalate kidney stones.

Kidney stones affect 5 to 10 percent of the world population who suffer from painful kidney stone episodes each year. The patients spent billions of dollars every year to treat kidney stones, including surgically removing them or repeatedly aiming high-energy shock waves at them until they disintegrate.

Researchers first identified O. formigenes as an organism essential to the body’s ability to break down harmful oxalate, also called oxalic acid, before it binds with calcium to form crystals that turn into kidney stones. Oxalate is an abundant chemical that forms as a byproduct of digestion. It’s also present in many common foods, including tea, broccoli, spinach and chocolate. Excess amounts of this naturally occurring organic compound has been linked to certain heart problems, kidney failure and, in some cases, death.

The results of the research are also expected to have applications for other diseases related to the overabundance of oxalate in the body, including cystic fibrosis. The focus of this research is twofold: to confirm whether the loss of Oxalobacter formigenes leads to a higher risk of producing oxalate, and to determine why the bacterium rarely regrows in animals that have become decolonized.

The reason why some people lack this vital intestinal bacterium is not known, but overuse of antibiotics has been linked to destruction of the organism. Researchers will attempt to reintroduce the bacteria into rats with a coated pill that passes through the stomach and releases in the intestine. The efforts will include variations in dosage, time of delivery and diet, if needed. Recent study has shown that daily enzyme treatment also may prevent kidney stone formation. It was found that giving laboratory animals a pill containing an enzyme before and after meals successfully reduces oxalate levels. It is possible this enzyme treatment could one day be used to manage kidney stones.