As the owner of a beagle, I know they can eat until they vomit, and then some. Thus, because of their enthusiastic vigor for eating, they can be prone to obesity. Aside from the strain the extra weight puts on their joints, it also renders them susceptible to a disease we normally associate with humans – diabetes. The typical diabetic dog is overweight, female, and middle aged. However, strides in research using dogs as models have benefitted both Fido and his owner.
Type 2 diabetes is more common in the human population and occurs when the body can no longer use insulin properly. Insulin, a hormone produced in the pancreas, helps the body absorb sugar, store excess sugar, and lower blood sugar levels. Insulin resistance occurs when insulin is produced, but not used. On the other hand, type 1 diabetes is an autoimmune disease where the pancreatic cells that normally produce insulin are unable to do so. Insulin therapy is always needed for this type. About 5 percent of people with diabetes are affected by type 1, and it is very similar to the type of diabetes dogs develop.
Dogs’ Contributions to Advancements in Diabetes Research
Diabetes has been described in medical literature since 1500 BCE, but it was not until 1889 that Oskar Minkowski and Joseph von Mering were able to demonstrate that removing the pancreas of a dog resulted in developing diabetes.
An effective treatment, however, was not devised until 1921. Before that, diabetes was considered fatal. The only treatment was to keep sugar intake to a minimum. A Canadian surgeon, Frederick Banting, and his assistant, Charles Best, found that injecting pancreatic cell extracts in dogs with induced diabetes could relieve diabetic symptoms. The extracts contained insulin. Later, Banting and a biochemist, Bertram Collip, began using cattle pancreases to create the extracts, and worked to purify the insulin so it could be tested in people.
Insulin is generally administered as a shot, but a pump can also continuously administer it. Arnold Kadish designed the first insulin pump in 1963, but it was a bulky device worn as a backpack. In 1976, Dean Kamen developed a wearable version. This breakthrough has meant more freedom for people with both type 1 and type 2 diabetes. Though there have been studies on insulin pumps in dogs, there currently are no commercially available insulin pumps for them.
Managing Diabetes in Dogs
Dogs actually benefit from many of the same treatment methods that people use to manage diabetes. For some dogs, oral medications are administered when insulin treatment isn’t working. Acarbose, a drug that inhibits carbohydrates’ ability to be converted into simple sugars, can be given to dogs when insulin isn’t working. This is one of only a few drugs that benefit dogs with diabetes.
As recently as 2013, researchers have been exploring the use of gene therapy in an effort to cure type 1 diabetes. By injecting functional genes that integrated into the dogs’ genome, the dogs’ systems were able to sense and respond to blood sugar level changes. The dogs were able to maintain normal blood sugar levels for more than four years after treatment. As diabetes in dogs is similar to type 1 diabetes in humans, this treatment has the potential to help both dogs and humans.
Dogs Helping People with Diabetes
While some dogs themselves live with diabetes, others have the unique ability to assist people living with the disease. Dogs can be trained to recognize when someone’s blood sugar is too low or too high. Just recently, we found out why. A naturally occurring chemical in breath rises when someone’s blood sugar drops, giving insight into how dogs are able to smell low blood sugar. This phenomenon creates new possibilities for tools that use a person’s breath to measure blood sugar, instead of using blood to measure it, a routine that can be costly and painful.
Dogs suffer from many of the same diseases and conditions we do, so their role in research and what researchers can glean from studying them gives new meaning to the phrase ‘man’s best friend.’