Markers of macrophage infiltration and measures of lipolysis in human abdominal adipose tissues

Abstract

Objective: We tested the hypothesis that high lipolytic responsiveness is related to increased expression of ATM genes in human adipose tissues. Design and Methods: Omental (OM) and subcutaneous (SC) fat samples were obtained surgically in 46 women (age: 47.2 6 4.7 years, BMI: 26.9 6 5.2 kg/m 2 ). Body composition and fat distribution were measured using dual energy X-ray absorptiometry and computed tomography. Lipolysis was measured by glycerol release in mature adipocytes isolated by collagenase digestion under basal-, isoproterenol (10 À5 M)-, and forskolin (10 À5 M)-stimulated conditions. Quantification of macrophage gene mRNA expression (CD11b, CD11c, and CD68) in whole adipose tissue was performed using real-time RT-PCR. Results: SC CD68 mRNA abundance was positively associated with isoproterenol-stimulated lipolysis (r ¼ 0.36, P < 0.05). This association remained significant after adjustment for total body fat mass (r ¼ 0.34, P 0.05). In the OM depot, CD11b mRNA abundance was positively associated with isoproterenol-stimulated lipolysis (r ¼ 0.42, P 0.005). This association remained significant after adjustment for total body fat mass (r ¼ 0.41, P 0.01). In subgroup analyses, high lipolytic rates in SC adipocytes were related to increased whole tissue expression of CD68 and CD11b in this compartment, independent of adiposity and fat cell size (P 0.001 and P 0.05). High lipolytic rates in OM adipocytes were related to increased whole tissue OM expression of CD11b, independent of adiposity and fat cell size (P 0.05). Conclusions: High adipocyte lipolytic responsiveness is related to increased expression of ATM markers in the corresponding compartment, independent of adiposity and fat cell size.

Omental adipocyte hypertrophy relates to coenzyme Q10 redox state and lipid peroxidation in obese women

“…Tissue samples were digested with collagenase type I in KrebsRinger-Henseleit buffer for 45 min at 37°C according to a modifi ed version of the Rodbell method (14)(15)(16). Cell suspensions were fi ltered through nylon mesh and washed three times with Krebs-Ringer-Henseleit buffer.…”

Low abdominal subcutaneous preadipocyte adipogenesis is associated with visceral obesity, visceral adipocyte hypertrophy, and a dysmetabolic state

“…In women, OM adipocytes are known to be smaller than SC cells independently of BMI 4 . Adipocyte hypertrophy is related to impaired adipose tissue function including high responses to lipolytic agonists, lower DGAT activity and macrophage infiltration 5 - 7 . Data linking adipocyte hyperplasia to obesity and metabolic alterations are more limited 8 .…”

Comparison of Methods for Analyzing Human Adipose Tissue Macrophage Content

“…CD206 is a mannose receptor that induces an antiinflammatory cell signaling cascade following activation (17,19). We initially tested a fluorescein isothiocyanate (FITC) conjugated CD11b antibody for total macrophages by flow cytometry (20) but experienced unacceptable variability, consistent with descriptions on the Purdue Cytometry Discussion List (an online forum for flow cytometry experts) (21) that adipose tissue samples gave excessive autofluorescence in the FITC channel. We changed to the allophycocyanin (APC) conjugated CD68 receptor antibody for flow cytometry to avoid FITC channel autofluorescence and to allow direct comparison with the antigen we selected for IHC.…”