The insulin-like growth factor (IGF) system and its relation to infliximab treatment in adult patients with Crohn's disease

Objective. Metabolic bone disease (MBD) and muscle wasting (MW) are serious complications in adult patients suffering from inflammatory bowel disease. These complications may be caused by alterations in the insulin-like growth factor (IGF) system. The aim of the present study was to assess changes in the IGF system in patients with active Crohn's disease (CD) before and during infliximab treatment. Material and methods. We studied 13 patients with therapy refractory CD, treated with infliximab (5 mg/kg body-weight) at baseline and after 2 weeks. The IGF system and markers of inflammation were examined at baseline, on days 2-5 and after 1, 4, and 8 weeks. Ten healthy age- and gender-matched persons served as controls. Results. Total IGF-I and IGF binding protein (IGFBP)-3 levels were reduced by 36% (p <0.05) and 27% (p <0.001), respectively, compared with those of controls, and normalized during the study period. Free IGF-I levels were reduced by 46% (p <0.05) compared with those of controls and remained suppressed. IGFBP-2 levels were increased at baseline by a factor 2.3 compared to controls (p <0.01) with partial normalization at the end of the study period. The Crohn's disease Activity Index, the Harvey Bradshaw Index, C-reactive protein, orosomucoid and albumin reached normal levels during infliximab treatment. Conclusions. Treatment with infliximab normalized circulating levels of total IGF-I and IGFBP-3, and partially normalized IGFBP-2, whereas free IGF-I remained suppressed. We suggest that the changes in the IGF system may be part of the catabolic state in active CD and may have an association with MBD and MW.