Clinical and biochemical factors associated with area and metabolic activity in the visceral and subcutaneous adipose tissues by FDG-PET/CT.

Abstract

Body fat distribution and inflammation may play a role in metabolic derangements and cardiovascular disease in obesity. The aim of this study is to investigate clinical and biochemical factors associated with area and metabolic activity in the visceral and subcutaneous adipose tissues (VAT and SAT). (18)F-fluorodeoxyglucose-positron emission tomography and computed tomography imaging was performed in 251 consecutive subjects (62.6 ± 9.3 y) for risk screening. We examined which clinical, anthropometric, metabolic, and inflammatory variables including advanced glycation end products (AGEs) and pigment epithelium-derived factor (PEDF) were independently associated with area and metabolic activity in VAT and SAT. Adipose tissue area was determined with computed tomography, whereas metabolic activity was assessed by (18)F-fluorodeoxyglucose uptake expressed as a target to background ratio (TBR) of blood-normalized standardized uptake. Serum levels of AGEs and PEDF were 9.81 ± 3.21 U/mL and 14.0 (range 10.8-17.7) μg/mL, respectively. Although the area in VAT and SAT was associated with waist circumference and sex, each adipose tissue area and TBR had different metabolic risk profiles. The TBR value in VAT was higher than that in SAT. In a multiple stepwise regression analysis, AGEs and medication for hypertension were independently associated with VAT TBR (R(2) = 0.102), whereas medication for diabetes, mean intima-media thickness, AGEs, and PEDF were the independent correlates of SAT TBR (R(2) = 0.132). The present study demonstrated that area and metabolic activity in VAT and SAT could be differently regulated, suggesting the involvement of AGEs and PEDF in adipose tissue inflammation.