Type 2 diabetes mellitus is an increasingly-common endocrinopathy in both cats and humans, and causes significant morbidity and mortality in pet cats.
Affected cats commonly require frequent hospital visits and the responsibility and cost of treating diabetic cats can place an emotional and financial burden on pet owners. This results in many diabetic cats being euthanased early in the course of treatment.
A proportion of cats and humans can enter a state of diabetic remission and no longer require insulin therapy. Human studies, and early evidence from feline studies, suggest that early treatment with intensive insulin protocols increases the chance of diabetic remission. This would also be expected to be the case in cats with diabetes mellitus. However, no rigid assessment of this aspect has been conducted in diabetic cats.
We have recently completed a study aimed to identify predictors of remission in diabetic cats and assess the rate of remission in diabetic cats treated with different insulin protocols. Our current study aims to investigate the benefit of incretin therapy (see below) in increasing the chance of diabetic remission and preventing cats in remission from relapsing. It has been recognised that once in diabetic remission, unfortunately, 30-40% of cats do not maintain this remission and will re-enter a diabetic state within a year. It is suspected that pancreatic beta-cell dysfunction is the most important explanation for this. Incretin-based drug therapy has been shown in humans with diabetes to improve beta-cell health, and promote (permanent) remission.
Among their multiple actions, the endogenous incretins and incretin-type drugs stimulate insulin secretion, suppress glucagon secretion, increase beta-cell mass and decrease gastric emptying. Type 2 diabetic patients have severely impaired incretin effect. In cats, it has been shown that Exenatide potentiates insulin secretion and suppresses glucagon secretion during hyperglycaemia and improves glycaemic control for more than a month after a single injection. It has also been shown that Exenatide is safe in cats.
In order to further investigate the benefit of incretin-based therapy in cats with diabetes, a group of newly diagnosed diabetic cats may receive a once monthly subcutaneous injection of a long-acting GLP-1 analogue (exenatide; Bydureon™) alongside their insulin injection therapy. Additionally, a group of previously diabetic cats that have entered remission will also receive a once monthly subcutaneous injection of a long-acting GLP-1 analogue in an effort to establish whether these cats are more likely to maintain the remission state compared to cats not receiving the drug.
All cats in these studies are patients of RVC Small Animal Referrals and benefit directly from participating in the trials. The experimental aspect of this work involves using tests and drugs that are commonly used in human medicine also in our patients. These tests and drugs therefore fall outside the veterinary surgeon’s act and are given/conducted under the Home Office Project License. If this work shows the drugs and/or tests are beneficial for the cats, they will become part of recognised veterinary practice.