Differences in Upper and Lower Body Adipose Tissue Oxygen Tension Contribute to the Adipose Tissue Phenotype in Humans

Upper and lower body adipose tissue (AT) exhibits opposing associations with obesity-related cardiometabolic diseases. Recent studies have suggested that altered AT oxygen tension (pO₂) may contribute to AT dysfunction. Here, we compared in vivo abdominal (ABD) and femoral (FEM) subcutaneous AT pO₂ in women who are overweight and have obesity, and investigated the effects of physiological AT pO₂ on human adipocyte function.

ABD and FEM subcutaneous AT pO₂ and AT blood flow (ATBF) were assessed in eight [BMI (body mass index) 34.4 ± 1.6 kg/m²] postmenopausal women who were overweight with obesity and impaired glucose metabolism. ABD and FEM AT biopsy specimens were collected to determine adipocyte morphology and AT gene expression. Moreover, the effects of prolonged exposure (14 days) to physiological AT pO₂ on adipokine expression/secretion, mitochondrial respiration, and glucose uptake were investigated in differentiated human multipotent adipose-derived stem cells.

AT pO₂ was higher in ABD than FEM AT (62.7 ± 6.6 vs 50.0 ± 4.5 mm Hg, P = 0.013), whereas ATBF was comparable between depots. Maximal uncoupled oxygen consumption rates were substantially lower in ABD than FEM adipocytes for all pO₂ conditions. Low physiological pO₂ (5% O₂) decreased proinflammatory gene expression, increased basal glucose uptake, and altered adipokine secretion in ABD and FEM adipocytes.

We demonstrated for the first time, to our knowledge, that AT pO₂ is higher in ABD than FEM subcutaneous AT in women who are overweight/with obesity, partly due to a lower oxygen consumption rate in ABD adipocytes. Moreover, low physiological pO₂ decreased proinflammatory gene expression and improved the metabolic phenotype in differentiated human adipocytes, whereas more heterogeneous effects on adipokine secretion were found.