Cushing Microbiome

Introduction: Patients with Cushing's syndrome (CS) present a typical phenotype including prominent features such as abdominal obesity and increased susceptibility to infections. The human gut microbiome responds to different pathological conditions, but hypercortisolism has not been studied. Aim of our study was to analyze the impact of chronic cortisol excess on the gut microbiome in patients with CS. Methods: We recruited prospectively 18 patients with endogenous CS from different etiologies (mainly pituitary CS). Patients gave a stool sample during active CS and 1-2 years after successful surgical treatment being in biochemical remission. The 16S rRNA gene was sequenced and clustered into Operational Taxonomic Units (OTUs). Rhea was used for further downstream analysis. Obese patients, in whom CS was excluded, and healthy lean young students served as control groups. Results: In comparison to lean controls, the gut microbiome of patients with florid CS showed severely disturbed microbial profile, whereas it was not significantly different from our morbidly obese controls . De-novo clustering revealed two intrinsic subgroups in CS, which show a unique microbial profile. Biochemical remission following curative surgery of CS was not associated with major changes of the gut microbiome. Conclusions: Patients with CS have a unique and severely disturbed gut microbiome.