Serine Phosphorylated IGF Binding Protein-1 (IGFBP-1) Accumulates in the Serum Following Burn Injury

Abstract

Burn injury is associated with early apoptotic death of T cells and Insulin-like growth factor-1 (IGF-I) is able to protect T cells from apoptosis. Association of IGF-I with its IGFBP (Binding Protein)-1 limits its bioavailability and serine phosphorylation of IGFBP-1 makes this worse because of increased affinity for IGF-I. The level of phosphorylated IGFBP-1 has been shown to increase in pediatric burn patients. Thus we hypothesize that a longitudinal study of burn patients will demonstrate 1) increased IGFBP-1 levels 2) increased IGFBP-1 phosphorylation 3) and decreased IGF-I levels over time. We obtained peripheral blood from burn patients within the first 24 hours after injury and daily thereafter. We used ELISA to measure the serum levels of IGF-I and IGFBP-1 and compared data using Student's t-test. In addition, we incubated samples containing equivalent amounts of IGFBP-1 with or without 50U calf intestinal phosphatase (CIP) and performed Western blots for IGFBP-1. There...