Alterations of IGF-binding proteins in patients with alcoholic liver cirrhosis

Abstract 

The protein synthetic activity of the liver is diminished in cirrhosis. The aim of this study was to investigate possible changes in the serum IGF–IGFBP system among patients with alcoholic liver cirrhosis (ALC). The results obtained demonstrated that serum IGF-I and IGF-II concentrations were significantly lower in patients with ALC than in healthy persons (P=0.0008 for IGF-I and 0.0002 for IGF-II). The IGFBP profile was markedly altered and the 34 kDa IGFBP from patients had higher affinity towards ¹²⁵I-IGF-II compared to the 34 kDa IGFBP of control individuals. Moreover, the 40–45 kDa IGFBP (in isolated complex with ¹²⁵I-IGF-II) exhibited diminished interaction with concanavalin A, wheat germ, and breadfruit lectins. Modification of the glyco-component of the 40–45 kDa IGFBP seems to be an early event in ALC since change in reactivity towards lectins was noticed in patients with ALC classified as Child score A, whose serum IGF-I and IGF-II levels were within reference limits (the existence of carbohydrate microheterogeneity of this IGFBP was also assessed by lectin-affinity electrophoresis). It is possible that these biochemical alterations may affect the functional activity of the IGFs by changing the dynamics and distribution of these growth factors in the organism.

Keywords: IGF, Binding proteins, Glycosylation, Liver cirrhosis