Insulin-like growth factor I (IGF-I) and its present significance in digestive system diseases

Abstract

Insulin-like growth factor I (IGF-I) is a main mediator of growth hormone’s (GH) action. Under physiological conditions, IGF-I is responsible for growth and development of organism through influence on proliferation and differentiation of cells. IGF-I is produced in almost all tissues of organism and its activity is determined by interaction with specific receptors (IGF-IR, IGF-IIR) and IGF-binding proteins (IGFBP-1 - IGFBP-6), and by proteases hydrolyzing IGFBPs as well. Currently, a surge of interest on insulin-like growth factor I as a potential factor contributing to the development of neoplasms, including neoplasms of digestive system, is observed. IGFBPs and IGF-IR may also be of importance in etiology and pathogenesis of cancer. It is assumed that high serum concentration of IGF-I may increase the risk of cancer development whereas high serum concentration of IGFBP-3 may inhibit the progression of the disease. Until recently, attempts of modulating the concentration of IGF-I with the use of pharmacological agents of diverse mechanisms of action under innovative anti-cancer therapies, have been made. Lately, it is pointed to the possibility of application of IGF-I in the management of certain diseases of digestive system. It was observed that IGF-I not only contributes to the maintenance of normal structure and function of epithelium in the gastrointestinal tract but also stimulates repair processes in damaged mucosa. Results of preliminary studies on the treatment of short bowel syndrome, gastric ulcer disease, enteritis induced by chemo- and radiotherapy, and inflammatory bowel disease with the use of exogenous IGF-I are encouraging.