What do people, dogs, cats, dolphins, lions, turtles and wolves all have in common? They all develop painful urinary stones, otherwise known as kidney stones.
Jody Lulich, D.V.M., Ph.D., professor in the University of Minnesota College of Veterinary Medicine, is hoping to find out why urinary stones form, how they can be eliminated from the body without surgery and how to prevent their recurrence.
Lulich focuses on a stone called calcium oxalate. The most common type of urinary stone, it affects 85 percent of human urinary stone sufferers.
The stone has three layers — calcium oxalate, calcium phosphate and bone —which form like the rings of a tree. Lulich’s research looks at why the bone forms on the calcium phosphate, which creates the uncomfortable and sometimes impassable stone. Understanding this interface between the calcium phosphate and bone could provide insight for disease prevention.
“Passing a urinary stone can be extremely painful, and might require surgery,” Lulich said. “Our goal is to minimize pain and suffering.”
When it comes to studying urinary stones, it’s possible that studying one species can benefit another. For instance, Lulich studies cats to understand how these stones develop in all species.
“We use cats as a model for human disease,” Lulich said. “Cats have an interesting model to offer because they have unique characteristics and habits that make them the perfect solution to investigate this difficult problem.”
Diet is a common therapy to prevent recurrence of urinary stones. “Unlike humans, we can control cat’s diets and keep it constant over the evaluation period,” Lulich said.
Also, cats reform stones faster than people. About 50 percent of humans reform stones in 5 to 10 years, while 50 percent of cats reform stones in two years. This shorter time period allows stone therapies to be evaluated more often.
The University of Minnesota College of Veterinary Medicine is home to the largest urology center in the world. The Minnesota Urolith Center analyzes 85,000 stone submissions each year to study how urinary stones form, how to remove them safely and how to prevent them from reforming. Just this year, the center received its millionth stone.
“We don’t completely understand why urinary stones form,” Lulich explained. “Our mission is to make surgical removal of stones of mere historical interest.”