Active Cushing's Disease is Characterized by Increased Adipose Tissue Macrophage Presence.
Context: While glucocorticoids (GCs) have potent anti-inflammatory actions, patients with hypercortisolism due to Cushing’s disease (CD) have increased circulating pro-inflammatory cytokines that may contribute to their insulin resistance and cardiovascular disease. The mechanisms and tissues that account for the increased systemic inflammation in patients with CD are unknown.
Objective: To determine if chronic endogenous GC exposure due to CD is associated with adipose tissue (AT) inflammation in humans.
Design, Setting, Participants: Abdominal subcutaneous AT samples from 10 patients with active CD and 10 age, gender, and BMI-matched healthy subjects were assessed for macrophage infiltration and mRNA expression of pro-inflammatory cytokines.
Main Outcome Measure: Using immunohistochemistry, AT samples were analyzed for the expression of Vimentin, caspase, CD3, CD4, CD8, CD11c, CD20, CD31, CD56, CD68, and CD163. Quantitative PCR was used to assess the mRNA gene expression of arginase, CD11b, CD68, EMR-1, IL-6, IL-10, MCP-1, and TNF-α.
Results: Immunohistochemistry revealed higher mean percent infiltration of CD68+ macrophages and CD4+ T lymphocytes, increased mean area of CD11c+ M1 macrophages, higher number of CD11c+ crown-like structures, and decreased Vimentin in the AT of patients with active CD compared to controls. PCR revealed no differences in mRNA expression of any analyzed markers in patients with CD.
Conclusions: Chronic exposure to GCs due to CD increases the presence of AT macrophages, a hallmark of AT inflammation. Hence, AT inflammation may be the source of the systemic inflammation seen in CD, which in turn may contribute to the obesity, insulin resistance, and cardiovascular disease in these patients.