Clinical Implications of UCP1 mRNA Expression in Human Cervical Adipose Tissue Under Physiological Conditions.

Abstract

The clinical implications of human brown adipose tissue (BAT) were investigated based on the analysis of cervical adipose tissue gene expression under normal physiological conditions. Matched-pair specimens of adipose tissue (AT) were collected from beneath the incision plane (subcutaneous AT) and from the area surrounding the carotid sheath (carotid AT) from 60 patients undergoing thyroidectomy. The mRNA expression of BAT-associated genes in these tissues was examined, and this expression was correlated with the clinical characteristics of the subjects. The UCP1 mRNA level was significantly higher in the carotid AT than in the subcutaneous AT. There was an inverse correlation between subject age and the ratio of UCP1 mRNA expression in the carotid AT relative to the subcutaneous AT, which is a measure of BAT activity (r = -0.459; P = 0.004), and there was a negative correlation between BMI and the ratio of UCP1 mRNA expression in subjects with higher BAT activity (r = -0.532; P = 0.016). UCP1 was identified as the only marker of cervical BAT in humans. There was a negative correlation between obesity and BAT activity in subjects with higher BAT activity, although BAT activity decreased with age.