Increased circulating IL-8 is associated with reduced IGF-1 and related to poor metabolic control in adolescents with type 1 diabetes mellitus.

BACKGROUND: A dysregulated growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis is well-recognized in children and adolescents with type 1 diabetes mellitus (T1DM). Decreased IGF-1 levels can also be found in chronic inflammatory diseases, while hyperglycemia promotes inflammatory cytokine production. Therefore, inflammatory cytokines may link poor metabolic control with GH/IGF-1 axis changes. This study examined the relationship between serum inflammatory cytokines and IGF-1 in adolescents (age 13-18) with TIDM in chronic poor (n=17) or favorable (n=19) glucose control. Poor control (PC) was defined as >or=3, consistent HbA1C>9% during the previous 2 years, while favorable control (FC) was consistent levels of HbA1C<9%. RESULTS: HbA1C (FC: 7.5+/-0.6%; PC: 10.5+/-0.9%, p<0.001) and interleukin (IL)-8 (FC: 3.7+/-4.0 pg/ml; PC: 7.4+/-4.3 pg/ml, p=0.01) were increased and IGF-1 (FC: 536.5+/-164.3 ng/ml; PC: 408.9+/-157.1 ng/ml, p=0.03) was decreased in patients with poor control compared to patients with favorable control. Moreover, IL-8 was inversely correlated with IGF-1 (r=-0.40, p=0.03) and positively correlated with HbA1C (r=0.36, p=0.03). CONCLUSIONS: In adolescents with T1DM and chronic, poor glucose control, increased serum IL-8 is associated with reduced IGF-1 suggesting a pro-inflammatory milieu that may contribute to alterations in the GH/IGF-1 axis.