Epsilon Open Archive

Abstract

Diabetes mellitus is considered a common endocrine disorder in dogs. The underlying pathology is, however, poorly understood. Epidemiological, genetic and clinical research, as well as the clinical management of diabetic dogs, requires an appropriate system of classification that provides a framework within which various forms and stages of diabetes mellitus can be identified and differentiated. The overall aim of this doctoral research was to further characterise the different subtypes of canine diabetes mellitus. In the first study, a population-based epidemiological study, breed- gender- and age-specific incidence rates were calculated, and survival after diagnosis was estimated. A major finding was that in some breeds such as elkhounds and border collies, only female dogs were affected by diabetes. In the second study, beta cell function was assessed in dogs through measurement of C-peptide before and after an intravenous injection of glucagon. Healthy dogs showed a marked increase in the serum concentration of C-peptide after glucagon stimulation, indicating that the test is suitable for the purpose. In most diabetic dogs, C-peptide did not increase after glucagon stimulation, indicating beta cell dysfunction. The test has a potential use for subtyping diabetes mellitus in newly diagnosed dogs. A specific subtype of diabetes, gestational diabetes mellitus, was clinically characterised in the third study. Gestational diabetes mellitus is rare in dogs, and the case series in this study is the largest one described to date. In the fourth study, diabetes mellitus was investigated in 63 Swedish and Norwegian elkhounds. From the latter two studies it was concluded that those elkhound breeds are predisposed to progesterone-related forms of diabetes mellitus (diœstrous and gestational diabetes mellitus), which have several characteristics in common with human gestational diabetes mellitus and may serve as a novel animal model for that disease. A new classification system for canine diabetes mellitus is proposed based on the basis of earlier studies and the newly gained knowledge. The following classes are proposed: juvenile; progesterone-related; secondary to pancreatic insult; endocrine tumours; iatrogenic; immune-mediated; and idiopathic.