Endocrine Abstracts

Background: Abdominal obesity is associated with insulin resistance and increased cardiometabolic disease risk, whereas lower-body fat accumulation seems protective against metabolic derangements. Differences in upper-body and lower-body adipose tissue (AT) function seem to underlie these opposing associations. Here, we investigated the inflammatory signature of upper- and lower-body AT in women with normal weight and obesity, as well as in human primary abdominal (ABD) and femoral (FEM) adipocytes.

Methods: Twenty-one healthy postmenopausal women (aged 50–65 years) with normal weight (BMI 18–25 kg/m²) and obesity (BMI 30-40 kg/m²) were recruited. The in vivo secretion of adipokines from ABD and FEM subcutaneous AT was determined after an overnight fast using the arterio-venous balance technique. Furthermore, adipokine expression and adipocyte size in ABD and FEM AT were examined. Finally, the expression and secretion of adipokines were investigated in vitro using differentiated human primary ABD and FEM subcutaneous adipocytes derived from the same individuals.

Results: Plasma leptin (P < 0.001) and PAI-1 (P = 0.036) concentrations, as well as abdominal and femoral adipocyte size were higher in women with obesity compared to normal weight. No significant differences in fat cell size and blood flow were found between ABD and FEM AT. There was significant net release of leptin and MCP-1 across ABD and FEM AT (all P = 0.001), and fractional release of MCP-1 was higher in ABD than FEM AT (P = 0.023). Gene expression of leptin (P = 0.010), PAI-1 (P = 0.080) and TNF-α (P = 0.090) were lower in ABD than FEM AT and increased in obesity. In vitro, IL-6, PAI-1 and leptin gene expression was higher, while adiponectin and DPP-4 gene expression were lower in adipocytes derived from the ABD compared to FEM region. Finally, ABD adipocytes derived from women with obesity secreted less MCP-1 compared to femoral adipocytes (P = 0.013).

Conclusions: The present study demonstrates for the first time that there are differences in the expression and secretion of pro-inflammatory adipokines between ABD and FEM AT and human primary adipocytes in postmenopausal women, independent of adipocyte size.