Having a diabetic dog or cat can be frightening and confusing for pet owners. Unfortunately, euthanasia is the leading cause of death for diabetic pets. But, caring for a pet with diabetes is feasible, once the pet owner is convinced to make the commitment to give it a try for 3 months, at which point it will likely become second nature.
Diabetes in dogs increasing
Diabetes is on the rise in both dogs and people. In fact, diabetes in dogs has doubled within the past 5 years.
Type 1 diabetes occurs in humans and dogs when the beta cells in the pancreas fail to make enough insulin, resulting in the accumulation of glucose to dangerous levels in the blood and urine. While Type 1 diabetes typically occurs in young people and is not considered to be a lifestyle-related disease, in dogs, diabetes occurs in adults later in life, and is influenced by diet and lifestyle. Dogs typically only get the Type 1 form, whereas cats get both Types I and Type II diabetes.
Epigenetic factors, such as aberrant DNA methylation, also pose a risk factor for development of Type 1 diabetes. Thus, diabetic individuals should eat foods that promote optimum DNA methylation, such as curcumin (turmeric) and those rich in folate.
Type 2 diabetes, caused by insulin resistance, occurs when the pancreas produces insulin, but the body cannot utilize it effectively. Type 2 diabetes is also known as adult-onset diabetes because it occurs later in life and is associated with lifestyle factors such as diet and obesity. The leading contributors to type 2 diabetes are obesity and eating carbohydrates with a high glycemic index (GI).
Current Methods to Control Diabetes
Diabetes mellitus (Types 1 and 2) in dogs and cats can be controlled with daily insulin administration. While several types of insulin have been used in the past to treat diabetic animals, the product licensed for pets today in North America is the porcine insulin zinc suspension (Vetsulin). Other products that have been used include recombinant human NPH insulin, recombinant human protamine zinc insulin, and insulin glargine (aka Lantus).
Insulin analogs are modified forms of native insulin but have the same physiologic effect. Insulin glargine (Lantus) and insulin detemir (Levemir) are synthetic long-acting insulin analogs used in humans, and have also become preferred choices for the treatment of diabetes mellitus in dogs and cats. Insulin glargine forms microprecipitates in the subcutaneous tissues, which results in slow absorption and a long duration of action for up to 24 hours in humans, dogs, and cats.
Results suggested that subcutaneous injection of insulin detemir every 12 hours is a viable treatment for diabetes mellitus in dogs, although the effective dose is lower, indicating that that it should be used with caution in small dogs.
Another option for treating diabetic cats, but not dogs, is the oral sulfonylurea product, glipizide (Glucotrol). It is safe for all except pregnant and nursing cats and should not be used in cats with sulfa drug allergies.
The US Food and Drug Administration approved the first insulin pen for dogs and cats in 2014 (VetPen). The device resembles a thick ballpoint pen, and contains porcine insulin zinc suspension (Vetsulin) cartridges. The product is delivered by turning a dial to select the prescribed dose, inserting the pen through the pet’s skin and pushing the release button, which is held in place for 5 seconds to deliver the insulin. Dogs or cats intolerant of pork products should not use the porcine insulin zinc suspension.
Regarding type-2 diabetes: while failure of the beta cells in the pancreas to make insulin is typically viewed as irreversible, a recent study in people showed that caloric restriction alone can reverse both beta cell failure and insulin resistance within just 1 week. Obese people and dogs are also known to be prone to metabolic syndrome, which promotes insulin resistance and affects many body systems including the nervous system, muscles, pancreas, kidneys, heart, liver and immune system.
Medical Management Developments
Exciting developments are taking place in genomic diabetes research, which might enable people and dogs to no longer require insulin injections. Researchers from Spain have used gene therapy to successfully regulate Type 1 diabetes in dogs for more than 4 years, without the side effects of hypoglycemia or other risks associated with conventional treatments.
In a single treatment session, the researchers injected five diabetic laboratory Beagles with the genes for glucokinase and insulin, compounds that are critical in maintaining normal blood glucose levels. The researchers inserted the genes into skeletal muscle using a non–pathogenic viral vector vehicle to effect the DNA transmission. Since skeletal muscle cells do not divide, the genes could be injected just one time and remain undisturbed for years to maintain normal blood glucose levels. After fine-tuning the procedure in companion dogs, the researchers plan to move on to testing on human patients.
American Diabetes Association. “Gene Therapy Used in Dogs to Treat Type 1 Diabetes”, 2013. Retrieved from http://www.diabetes.org/for-media/2013/gene-therapyused-in-dogs-to-treat-type1-diabetes.html.
Becker K. “A Single Treatment Cures Diabetes: How to Protect Your Pet Now”, 2013. Retrieved from http://healthypets.mercola.com/sites/healthypets/archive/2013/03/27/dog-diabetes-treatment.aspx.
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Fracassi F, Corradini S, Hafner M et al. Detemir insulin for the treatment of diabetes mellitus in dogs. J Am Vet Med Assoc, 2015; 247:73-78.