Adipocyte fatty acid-binding protein is a plasma biomarker closely associated with obesity and metabolic syndrome

FABP) is traditionally thought to be a cytosolic fatty acid chaperone expressed in adipocytes. Mice with targeted disruption of the A-FABP gene exhibit a striking phe-notype with strong protection from insulin resistance, hyperglycemia, and atherosclerosis. The clinical rele-vance of these findings remains to be confirmed. Methods: We used tandem mass spectrometry–based proteomic analysis to identify proteins secreted from adipocytes and present in human serum. We measured serum A-FABP concentrations in 229 persons (121 men and 108 women; age range, 33–72 years) including 100 lean [body mass index (BMI) <25 kg/m2] and 129 over-weight/obese individuals (BMI>25 kg/m2) selected from a previous cross-sectional study. Results: A-FABP was released from adipocytes and wa