Insulin-like growth factor system and inflammatory bowel disease
Few reports concerning the levels and the importance of
insulin-like growth factors (IGFs) and IGF binding proteins
(IGFBPs) in the serum of patients with inflammatory
bowel disease (IBD) have been published.
Insulin-like growth factor(IGF) system has properties that
are potentially relevant to IBD. The IGF system is a system
complex composed of IGF-I and IGF-II as well as at least
six different IGF binding proteins (IGFBP).IGF-I expression
has been shown in lymphocytes, macrophages and fibroblasts.
IGF-I is a potent mitogen for fibroblasts and
smooth muscle cells and induces collagen synthesis in vitro,
appearing to be important in tissue remodeling and repair.
Proinflammatory cytokines such as interleukin-1 (IL-
1) may play a role in IGF-I production linking the IGF system
with the inflammatory process in IBD patients. It has
been suggested that IBD patients may have low IGF-I and
IGFBP levels. In recent years the effect of regulatory peptides
such as growth hormone (GH) and IGF-I in intestinal
growth and repair has been emphasized. Trials of growth
hormone in combination with a high-protein diet in short
bowel syndrome patients as well as Crohn’s disease (CD)
patients have been encouraging. It has been suggested that
the IGF and IGFBP system may be abnormal in IBD patients
during this chronic inflammatory process, yet there
is no data is on the exact impact of inflammation on this
down-regulation and the interaction between the interleukins
and the IGF and IGFBP system, in IBD patients. Key words: IGF system, IGF-I, IGF-II, IGFBP3, IGFBP,
inflammatory bowel disease (IBD), Crohn’s disease (CD),
ulcerative colitis (UC).