CONTEXT: Six transmembrane protein of prostate 2 (STAMP2) is a counterregulator 
of adipose inflammation and insulin resistance in mice. Our hypothesis was that 
STAMP2 could be involved in human obesity and insulin resistance.
OBJECTIVE: The objective of the study was to elucidate the role of adipose 
STAMP2 expression in human obesity and insulin resistance.
DESIGN: The design was to quantify STAMP2 in human abdominal sc and omental 
white adipose tissue (WAT), isolated adipocytes, and stroma and in vitro 
differentiated preadipocytes and relate levels of STAMP2 in sc WAT to clinical 
and adipocyte phenotypes involved in insulin resistance.
PARTICIPANTS: Nonobese and obese women and men (n = 236) recruited from an 
obesity clinic or through local advertisement.
MAIN OUTCOME MEASUREMENT: Clinical measures included body mass index, body fat, 
total adiponectin, and homeostasis model assessment as measure of overall 
insulin resistance. In adipocytes we determined cell size, sensitivity of 
lipolysis and lipogenesis to insulin, adiponectin secretion, and inflammatory 
gene expression.
RESULTS: STAMP2 levels in sc and visceral WAT and adipocytes were increased in 
obesity (P = 0.0008-0.05) but not influenced by weight loss. Increased WAT 
STAMP2 levels associated with a high amount of body fat (P = 0.04), high 
homeostasis model assessment (P = 0.01), and large adipocytes (P = 0.02). 
Subjects with high STAMP2 levels displayed reduced sensitivity of adipocyte 
lipogenesis (P = 0.04) and lipolysis (P = 0.03) to insulin but had normal 
adiponectin levels. WAT STAMP2 levels correlated with expression of the 
macrophage marker CD68 (P = 0.0006).
CONCLUSION: Human WAT STAMP2 associates with obesity and insulin resistance 
independently of adiponectin, but the role of STAMP2 in obesity and its 
complications seems different from that in mice.