The 11β-hydroxysteroid dehydrogenase type 1 inhibitor SPI-62 prevents morbidity in a mouse model of Cushing's syndrome

11{beta}-hydroxysteroid dehydrogenase type 1 (HSD-1) inhibitors represent a potential therapeutic approach for patients with Cushings syndrome, autonomous cortisol secretion (ACS), or iatrogenic glucocorticoid (GC) excess. We assessed whether the HSD-1 inhibitor SPI-62 prevents GC-associated morbidity in a mouse Cushings syndrome model. Corticosterone (CORT) was administered to mice for 5 weeks. Animals who received CORT were randomized between vehicle and 3 SPI-62 regimens. A control group received neither CORT nor SPI-62. Body weight was measured daily to enable weight-based SPI-62 administration. Food consumption by pair-housed animals was reported weekly. Insulin sensitivity was evaluated by fasting homeostatic model assessment of insulin resistance. Adiposity and skeletal myopathy were measured using magnetic resonance imaging and post-mortem weights of fat depots and skeletal muscles. Grip strength was measured with a digital meter. Ambulation behavior in an open field maze was assessed. Post-mortem dermal thickness was quantified. Skin structure was evaluated by histology. CORT was associated with decreased insulin sensitivity, increased adiposity, skeletal myoatrophy, reduced grip strength, decreased dermal thickness, and skin structural changes. A trend of increased food consumption and an unexpected biphasic weight change were observed with CORT. SPI-62 attenuated all observed adverse effects in a dose-dependent manner. In general, results for the high SPI-62 regimen were similar as those in animals who received no CORT, suggesting that full HSD-1 inhibition should be maintained throughout a dose interval to mitigate the effects of glucocorticoid excess.