Thrombospondin 1 as a novel biological marker of obesity and metabolic syndrome☆

Thrombospondin 1 (THBS1 or TSP-1) is an adipose-derived matricellular protein, which has recently been highlighted as a potential mediator of insulin resistance and adipose inflammation in obesity.In this study, we aimed to determine the clinical significance of THBS1 as a novel biological marker of visceral obesity, metabolic syndrome, and diabetes.The THBS1 mRNA level was quantified with real-time PCR in human adipose tissues obtained from 16 non-obese subjects. The relationships between serum THBS1 level and obesity/diabetes traits as well as the diagnostic components of metabolic syndrome were assessed in 164 normal-weight or overweight/obese subjects (78 males and 86 females; mean age, 50.4; mean BMI, 29.8) with analysis of covariance (ANCOVA) and regression analyses.THBS1 was predominantly expressed in visceral adipose tissues relative to subcutaneous adipose tissues (P0.001). The visceral THBS1 expression was positively associated with the body mass index (BMI; γs=0.54, P=0.033). ANCOVA demonstrated that the THBS1 level is associated with abdominal obesity (P0.001), hyperglycemia (P=0.02), and hypertension (P=0.04). Multivariable regression analysis suggested an association between serum THBS1 and fasting plasma glucose levels. The associations between serum THBS1 levels and obesity/diabetes traits were found preferentially in women (BMI, γs=0.30, P=0.05; FPG, γs=0.26, P=0.016). Subanalyses demonstrated that the association with obesity traits was predominantly found in premenopausal women (BMI, γs=0.41, P=0.007), whereas the association with diabetes traits was predominant in postmenopausal women (HbA1c, γs=0.38, P=0.01). During medical weight reduction treatment, the change in the serum THBS1 level was associated with the change in BMI and HbA1c in pre- and postmenopausal women, respectively.Serum THBS1 is a useful biological marker of obesity and metabolic syndrome in Japanese subjects, particularly in women. THBS1 may act as a critical circulating factor that couples obesity with metabolic syndrome and diabetes in humans.