Endocrine Abstracts

Background: In patients with overt Cushing’s syndrome (CS) chronic endogenous excess of cortisol drives dysregulation of innate and adaptive immunity, characterised by increased monocyte and decreased lymphocyte counts. The impact of ‘sub-clinical’ CS in patients with cortisol-producing adenomas (CPA) and mild autonomous cortisol secretion (MACS) remain poorly defined. We hypothesise that macrophage polarisation and activation can be altered in both patients with CPA-CS and CPA-MACS leading to dysregulation of macrophage immune function.

Methods: Primary human macrophages were polarised into M1-like inflammatory type by adding TNFα (10ng/ml) and IFNγ (20ng/ml) and co-treated with 10% serum from 14 patients with adrenocortical adenomas, including 5 CPA-MACS, 4 CPA-CS, and 5 sex/age-matched endocrine inactive (EIA) controls, for 24 hours. Inflammatory and anti-inflammatory cytokine levels and corresponding gene expression were analysed by ELISA and RT-qPCR, respectively, and correlated to demographics and degree of steroid secretion.

Results: The marker of pro-inflammatory activation IL6 was decreased in M1-like polarised macrophages in response to CPA-MACS (P = 0.0389) and CPA-CS(P = 0.0283) patients’ serum when compared to EIA, while gene expression showed a non-significant decrease in CPA-MACS (P = 0.0794) and CPA-CS (P = 0.1302). GILZ (glucocorticoid-induced leucine zipper) gene expression was slightly increased in CPA-CS (P = 0.2830), but not in CPA-MACS (P = 0.9921) vs EIA. The pro-resolving M2-like macrophage marker CD163 gene expression was slightly increased in CPA-CS (P = 0.1545) and CPA-MACS (P = 0.1761) vs EIA. CD163 gene expression positively correlated with gene expression of GILZ (P < 0.0001) and anti-inflammatory marker CD64 (P = 0.0038). CD163 gene expression positively correlated with cortisol levels after overnight Dexamethasone suppression test (P = 0.0153) and tumour size (P = 0.08).

Conclusions: Both patients with CPA-MACS and CPA-CS showed suppression of M1-like inflammatory polarisation makers and a changing profile of pro-resolving M2-like polarisation. We plan to increase our patient cohorts and investigate M1 to M2 polarisation induced by the patient’s serum to identify the mechanism of immune dysregulation.