Dehydroepiandrosterone Sulfate (DHEAS) as a potential biomarker for assessing the etiology of canine naturally occurring Cushing’s Syndrome

Dissertação de Mestrado Integrado em Medicina Veterinária, área científica de Clínica ; DEHYDROEPIANDROSTERONE SULFATE (DHEAS) AS A POTENTIAL BIOMARKER FOR ASSESSING THE ETIOLOGY OF CANINE NATURALLY OCCURRING CUSHING’S SYNDROME - Naturally occurring Cushing’s Syndrome (CS) is a common endocrine disorder in dogs. It is usually caused by a pituitary tumor (pituitary-dependent hypercortisolism; PDH) or a functional adrenocortical tumor (adrenal-dependent hypercortisolism; ADH). Endogenous adrenocorticotropic hormone (eACTH) measurement associated with imaging tests is one of the most reliable methods for differentiating PDH from ADH. However, the results may be ambiguous and are not always straightforward. In humans, dehydroepiandrosterone sulfate (DHEAS) levels are usually significantly lower in ADH than in PDH and serve as a method to determine the etiology of CS. The main aim of this study was to assess whether DHEAS measurement can help differentiate between PDH and ADH in dogs with CS. Additionally, we assess potential differences between sexes and the correlation between DHEAS and eACTH concentrations. A multicenter, retrospective, cross-sectional study was conducted focusing on dogs diagnosed with CS and concurrent measurement of eACTH levels, divided according to the suspected etiology. DHEAS concentrations were determined using a competitive ELISA kit. DHEAS levels were evaluated for the total number of dogs and for different groups divided by sex. The data were assessed with descriptive statistics and adequate nonparametric tests. This study included 38 dogs (19 males and 19 females, five with ADH and 33 with PDH). Regarding the neutered status, three females and 10 males were intact. Intact males showed higher median DHEAS concentrations than neutered males. Spearman's correlation evidenced a statistically significant positive correlation between DHEAS and eACTH levels, but only in females. ROC curve analysis demonstrated poor ability of DHEAS to differentiate PDH from ADH and the Mann-Whitney test did ...