Increased lipocalin 2 levels in adolescents with type 2 diabetes mellitus

Bone can act as an endocrine organ through the secretion of bone-specific hormones, i.e., osteokines. Recent research has demonstrated that lipocalin 2 (LCN2) secreted by osteoblasts are part of an important endocrine system that is finely tuned with other organs to ensure homeostatic balance and health. The aim of this study was to explore the association between bone and glucose metabolism in adolescents with obesity and type 2 diabetes mellitus (DM2).

The participants were 8 adolescents with DM2 (5 males, 3 females; age: 17.0 (14.0-20.0) years, median (interquartile range)), 14 adolescents with simple obesity (9 males, 5 females; age: 13.5 (12.4-15.5) years), and 15 controls (6 males, 9 females; age: 13.3 (11.0-15.0) years). Serum LCN2 and under-carboxylated osteocalcin (un-OC) levels were measured using enzyme-linked immunosorbent assays.

The LCN2 levels were higher in patients with DM2 (58.1 (34.2-95.0) ng/mL; median (interquartile range)), but not in those with obesity (30.8 (23.1-38.3) ng/mL), when compared to the controls (18.2 (9.8-25.7) ng/mL). In the whole study group overall, serum LCN2 was positively correlated with the Model Assessment of Insulin Resistance score (r=0.339, p=0.046) and body mass index (r=0.580, p<0.0001), and negatively correlated with adiponectin (r=-0.462, p=0.005). A multiple stepwise regression model showed that serum adiponectin was an independent predictor of serum LCN2.

The results of this study indicate that further investigations are warranted to determine whether LCN2 may act as a sensitive indicator of early-stage insulin resistance.