Understanding inherited causes of canine bloat

Laura Nelson, assistant professor in the MSU College of Veterinary Medicine Department of Small Animal Clinical Sciences (SCS) and principal investigator in the project, has been awarded a 2-year grant to fund research on the causes of Gastric dilatation-volvulus (GDV) in dogs. The grant was awarded by the American Kennel Club Canine Health Foundation (CHF) on October 4, 2013.

When a dog gets bloat, gas fills the dog's stomach, the stomach twists completely around, the gas has no way to escape, and blood and air supply to the stomach are cut off. As the stomach swells, it presses against the abdominal wall and pushes against large blood vessels. Shock is usually the cause of death. The whole progression can happen in a matter of minutes or hours, and surgery is required to save the dog's life.

While the cause of bloat is unclear, there is a strong predisposition in some dogs and it is generally thought that GDV is influenced by both genetic and environmental factors.

"Not every dog is going to get it," says Nelson. "But there is a strong predisposition in some dogs. Older, nervous, and large and giant dogs breeds -- particularly Great Danes (and similar deep-chested dogs) -- are most prone to bloat. But we still don't know what causes it. That's what we want to know -- why some dogs get bloat while others don't."

Nelson's team is investigating the relationship of motility -- contractions responsible for the digestion of food -- with increased GDV risk, and hopes to define the biochemical and genetic alterations that may be associated with hypomotility -- abnormally weak contractions. The researchers also will evaluate the expression of the hormones motilin and ghrelin -- regulators of GI motility -- as a predictor of predisposition to GDV.

In the short term, the research findings may provide clinicians with data that would allow them to make informed decisions about when to use preventative medications or conduct targeted prophylactic surgery -- gastropexy -- in at-risk dogs. This procedure surgically attaches the stomach to the abdominal wall in order to prevent twisting. It is an effective procedure that is well tolerated, but, Nelson notes, it is an invasive procedure that may not be necessary in some dogs. There currently is not a good way to determine who to recommend it for.