Endocrine Abstracts

JOINT1080

Background: Adrenal Cushing’s syndrome (CS) is characterized by chronic, endogenous cortisol excess, which disrupts innate and adaptive immune functions. This dysregulation is observed as increased monocyte and reduced lymphocyte counts. However, the effects of “subclinical” CS in patients with cortisol-producing adenomas (CPA) and mild autonomous cortisol secretion (MACS) remain insufficiently understood. We hypothesize that macrophage polarization and activation may be altered in these patients, potentially leading to significant immune dysfunction.

Methods: Our cohort included 14 patients, i.e. 5 with CPA-MACS, 4 with CPA and overt CS (CPA-CS), and 5 sex- and age-matched patients with endocrine-inactive adenomas (EIA) as controls. Serum samples were collected during standard visits, centrifuged within 1–2 hours from collection, and stored at −80 °C. Primary human macrophages were polarized to an M1-like inflammatory state by adding TNFα (10 ng/ml) and IFNγ (20 ng/ml), followed by co-treatment with 10% serum from patients with adrenocortical adenomas. The macrophages were incubated for 24 hours, and inflammatory and anti-inflammatory cytokine levels and gene expression were measured using ELISA and RT-qPCR techniques. Cytokines and gene expression levels were correlated with clinical parameters (e.g. age, sex, tumour size) and degree of cortisol secretion (e.g. cortisol after overnight dexamethasone test, ACTH, and DHEAS levels).

Results: Pro-inflammatory markers such as TNFα exhibited a slight decrease in M1-polarized macrophages exposed to serum from both CPA-MACS (P=0.1916) and CPA-CS (P=0.1217) patients when compared to controls. A similar pattern was observed for IL6, with significant reductions noted in CPA-MACS (P=0.0389) and CPA-CS (P=0.0283) serum-treated macrophages compared to EIA. Gene expression data indicated non-significant trends in IL6 reduction in both CPA groups (CPA-MACS: P=0.0794, CPA-CS: P=0.1302). Additionally, GILZ (glucocorticoid-induced leucine zipper) gene expression was modestly elevated in CPA-CS patients (P=0.2830), though no change was observed in CPA-MACS (P=0.9921). The pro-resolving M2-like marker CD163 showed slight increases in gene expression in both CPA-MACS (P=0.1761) and CPA-CS (P=0.1545) groups compared to EIA controls. Notably, CD163 expression was strongly correlated with GILZ (P<0.0001) and the anti-inflammatory marker CD64 (P=0.0038). The ratio of IL6 to CD163, reflecting M1-to-M2 polarization, was elevated in CPA-CS samples (P=0.0614). Additionally, CD163 expression correlated with post-ONDST cortisol levels (P=0.0153) and tumour size (P=0.08).

Conclusions: Both CPA-MACS and CPA-CS patients demonstrated suppression of M1-like inflammatory markers and a shift towards M2-like polarization, which could contribute to immune dysregulation. Further experiments with a larger cohort and additional functional assays are ongoing to identify the mechanisms driving these immune alterations.