Age, Sex, and Depot Differences in Adipose Tissue from Obese Subjects
Authors: Porter Jay W , Welly Rebecca , Spencer Nicole , Pitt James , Vieira‐Potter Victoria J , Kanaley Jill A 
Published: June 2021

Purpose

Adipose tissue (AT) distribution and metabolism are largely affected by the sex hormone, estrogen (E2), presumably through E2 receptors (ER) a and b. In both males and females, E2 biosynthesis in AT occurs through aromatase enzyme, which is responsible for converting androstenedione to estrone. Menopause, loss of ovarian E2, associates with an abrupt increase in metabolic disease risk for reasons that are not fully understood, implicating E2 signaling within AT as playing a role in metabolic health. The purpose of this study was to determine the individual and combined effects of menopause and age on AT depot‐specific immunometabolic characteristics, in morbidly obese, age matched, men and women.

Methods

34 women (20 Pre‐menopausal (PRE), 14 Post‐menopausal (POST)) and 27 age‐matched men (M) (14 M‐PRE, 13 M‐POST) undergoing bariatric surgery consented to collection of omental (OM) AT; 26 of which consented to collection of abdominal subcutaneous (SQ) AT. Blood samples were collected prior to surgery. AT samples were immediately processed for histological, gene, and protein analyses.

Statistics

2‐way ANOVA for age group (A), sex (S), and A*S interactions were performed; p<0.05 was considered significant.

Results

Blood glucose, cholesterol, triglycerides, and HDL‐c were similar between groups; whereas, free fatty acids were significantly higher in females than males (1.07±0.04 vs. 0.95±0.05 mmol/L, respectively, p=0.049). OMAT cell size was larger in males than females (6382.0±521.1 vs. 4610.4±521.1 mm2, respectively, p=0.028); SQAT cell size was not different by S or A. SQAT gene expression (but not protein content) of ERb was significantly higher in females than males (1.21±0.22 vs. 0.60 ± 0.12, p=0.049). ERa gene expression was similar between A and S in OM and SQAT but there was a trend toward A*S interaction (p=0.052) in ERa protein in OMAT such that POST > than PRE, M‐PRE, and M‐POST, all p values <0.01. There was an A*S interaction for OMAT gene expression of aromatase (p=0.014); M‐Post > POST (p=0.023) and M‐POST > M‐PRE (p=0.044). The older age group had increased expression of SQAT TNFa (p=0.009). In SQAT, an A*S interaction (p=0.025) occurred in NFkB protein content, such that PRE < POST (p=0.092) and PRE < M‐PRE (p=0.076). Mitochondrial protein of electron transport chain (ETC) complexes (C) in SQAT had significant A*S interactions for C 2 and 3 (p=0.040 and 0.027, respectively). Post hoc differences in SQAT C2 PRE < POST (p=0.043) and C3 POST > PRE (p=0.060) and POST > M‐POST (p=0.065). C1 tended to follow similar patterns between A and S as C 2 and 3, A*S interaction p=0.055. OMAT ETC protein content was similar between A and S. An A*S trend (p=0.063) in SQ UCP1 content was observed such that POST > PRE (p=0.051) and POST > M‐POST (p=0.062); OMAT UCP1 was similar by A and S.

Conclusion

In morbid obesity, loss of E2 and aging may differentially affect OMAT E2 signaling pathways in men and women. Conversely, loss of E2 and aging affect SQAT mitochondrial and inflammatory pathways.

Support or Funding Information

Research supported by Dr. Kanaley RO1DK101513

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.