Research On Significance And Expression Of Brown Adipose Tissue Around Cortisol-producing Adenoma

Objective The objective of this study was to determine the presence of brown adipose tissue(BAT)in the periadrenal adipose depot in patients with different types of adrenal tumours and estimate the association between BAT expression and metabolic risks of patients with adrenal adenoma.Method Sixty-two patients who underwent adrenalectomy for benign adrenal tumours were enrolled in this study.The specific protein of BAT-uncoupling protein 1(UCP1)was measured by immunohistochemistry and Western blot in the periadrenal adipose tissue to quantitatively determine the expression of BAT in patients with different types of adrenal adenoma.Anthropometric data,fat distribution(visceral fat area,subcutaneous fat area),biochemical data(fasting glucose,blood lipid)and adrenal hormone levels(24-hour urinary free cortisol,serum aldosterone,metanephrine and normetanephrine)were determined.Results: The BAT activity in the PHEO(pheochromocytoma)group was significantly higher than in the CPA(cortisol producing adenoma)and NFA(nonfunctioning adrenal adenoma)groups(P<0.001 and P=0.010).The BAT activity in the CPA(aldosterone producing adenoma)group was significantly lower than in the APA group(P=0.001).The BAT activity didn’t show any correlation with age and sex.BAT activity was positively correlated with MNs(metanephrine plus normetanephrine)(R=0.286,P=0.031)and negatively correlated with UFC(urinary free cortisol)(R=-0.325,P=0.029).Blood lipid(triglyceride,low density lipid,high density lipid,cholesterol)were not correlated with BAT activity.Fasting blood glucose was significantly inversely correlated with BAT activity(R=-0.282,P=0.026).The VFA(visceral fat area)(R=-0.422,P=0.004)and adrenal tumour types(R= 0.318,P=0.024)were the two independent factors that significantly affected BAT activity(in log scale)in the periadrenal fat depot.Conclusions: Brown adipose tissue is differentially expressed in patients with different adrenal tumors.Brown adipose withdrawal is associated with the central obesity,diabetes mellitus and other metabolic risks found in patients with Cushing’s syndrome and nonfunctioning adrenal adenoma.