Subcutaneous adipose tissue produces soluble TNFR-I (P=0.002) and IL-6 (P<0.001), and concentrations of both soluble TNFR isoforms correlate significantly with BMI and percent body fat.
Observational
Human subcutaneous adipose tissue produces soluble TNFR-I and IL-6 in vivo, and their levels correlate with the degree of adiposity.
p-value: p=0.002
To investigate in vivo adipose tissue production of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and their soluble receptors: TNF receptor type I (sTNFR-I), TNF receptor type II (sTNFR-II), and IL-6 receptor (sIL-6R), we determined arteriovenous differences in their levels across abdominal subcutaneous adipose tissue in obese subjects. Subjects had a median (interquartile range) age of 44.5 (27-51.3) yr, body mass index (BMI) of 32.9 (26. 0-46.6) kg/m(2), and %body fat of 42.5 (28.5-51.2) %. Although there was not a significant difference in the arteriovenous concentrations of TNF-alpha (P = 0.073) or sTNFR-II (P = 0.18), the levels of sTNFR-I (P = 0.002) were higher in the vein compared with artery, suggesting adipose tissue production of this soluble receptor. There was a significant arteriovenous difference in IL-6 (P < 0.001) but not in its soluble receptor (P = 0.18). There was no relationship between TNF-alpha levels and adiposity indexes (r(s) = 0.12-0.22, P = not significant); however, levels of both its soluble receptor isomers correlated significantly with BMI and %body fat (sTNFR-I r(s) = 0.42-0.72, P < 0.001; sTNFR-II r(s) = 0.36-0.65, P < 0.05- <0. 001). IL-6 levels correlated significantly with both BMI and %body fat (r(s) = 0.51, P = 0.004, and r(s) = 0.63, P < 0.001), but sIL-6R did not. In conclusion, 1) soluble TNFR-I is produced by adipose tissue, and concentrations of both soluble isoforms correlate with the degree of adiposity, and 2) IL-6, but not its soluble receptor, is produced by adipose tissue and relates to adiposity.
Mohamed‐Ali et al. (1999) conducted an observational in Obesity. Arteriovenous differences across abdominal subcutaneous adipose tissue was evaluated on Arteriovenous differences in sTNFR-I levels (p=0.002). Subcutaneous adipose tissue produces soluble TNFR-I (P=0.002) and IL-6 (P<0.001), and concentrations of both soluble TNFR isoforms correlate significantly with BMI and percent body fat.