Gastrointestinal Inflammation and the Circulating IGF System in Humans

Abstract

Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) have important anabolic functions in normal tissue growth, which in excess may lead to tumorigenesis. In the present study, circulating IGF-I, IGF-II and their binding proteins (IGFBP-3, IGFBP-2 and IGFBP-1) were determined in 92 adult patients with gastrointestinal inflammation (Crohn's disease, colitis ulcerosa, gastritis, duodenitis errosiva, gastrointestinal candidiasis, and rotaviral and adenoviral enteritis). Serum IGF concentrations were measured by radioimmunoassay, while IGFBP profiles and IGFBP proteolytic patterns were characterized by immunoblotting. Concentrations of both IGF-I and IGF-II were significantly (p < 0.001) lower in patients than in healthy subjects. Immunoblotting demonstrated a decreased amount of intact IGFBP-3 (by approximately 60%), whereas IGFBP-2 and IGFBP-1 were increased (approximately 1.7 and 3.5-fold, respectively). No alteration in either fragmentation pattern or relative degree of proteolysis was detected in patients compared to the control group. It may be concluded that the IGF system is seriously imbalanced in patients with gastrointestinal inflammation, regardless of primary cause. These findings may help towards a better understanding of the metabolic outcome of the inflammatory process, and possibly in predicting the efficiency of patient recovery.

Insulin-like growth factor 1

“…These IGFBPs may be altered with nutritional status (reviewed in [61]), inflammation [62, 63], or resection [64, 65], as well as following TPN or rhGH administration [64]. A discussion of IGFBPs is beyond the scope of this review, but evaluation of the role of IGFBPs in IGF1, GLP2, or GH action in the intestine is an area for additional research.…”

The effect of laparoscopy on the IGF system in patients diagnosed with acute cholecystitis

“…Immunoblotting employed goat polyclonal anti‐IGFBP‐3, anti‐IGFBP‐2 and anti‐IGFBP‐1 antibodies (all from DSL) and a HRP‐conjugated swine anti‐goat antibody (Biosource, Camarillo, CA, USA). IGFBPs were detected using enhanced chemiluminescence 17 . The intensity of immunoreactive protein bands was determined using a Bio‐Rad Gel Doc 1000 image analyser coupled to Multi Analyst Software and AIDA.…”

Separation of the molecular forms of the insulin-like growth factor (IGF)—Binding proteins by affinity chromatography

“…Immunoblotting was performed using affinity purified goat polyclonal anti-IGFBP-1, anti-IGFBP-2 and anti-IGFBP-3 antibodies (IgG fraction, DSL, Webster, USA), followed by an anti-goat IgG antibody coupled to horseradish peroxidase (Biosource, Camarillo, USA). Immunoreactive proteins were visualized with an enhanced chemiluminescence (ECL) reagents (Amersham, Aylesbury, UK) [34].…”