Does insulin-like growth factor 1 contribute in red blood cell transfusions to the pathogenesis of retinopathy of prematurity during retinal neovascularization?

Background: Red blood cell (RBC) transfusions are associated with the development of retinopathy of prematurity (ROP). During the period of retinal neovascularization a rise of insulin-like growth factor 1 (IGF-1) may trigger rapid growth of new blood vessels. Objectives: To study endocrine factors in RBC transfusions that might be of importance for ROP. Methods: IGF-1, IGF-2 and their binding proteins 1 - 3 (IGFBP- 1 - 3) were determined by radioimmunoassays in 7 very-low-birthweight (VLBW) infants with ROP 6 stage 2 receiving a RBC transfusion, in 10 controls ( VLBW infants with ROP <= stage 1, no transfusion), in supernatants of 7 RBCs and of 5 washed RBCs (WRBC). Results: IGF-1 ( mean +/- SD) in infants with ROP was 20.0 +/- 4.2 mu g/l, in controls 35.9 +/- 15.2 mu g/l (Mann-Whitney U test, p = 0.030). IGF-1 in RBC was 12.88 +/- 5.03 mu g/l and in WRBC 0.45 +/- 0.74 mu g/l ( average of the three-course washing procedure). IGF-2 in infants with ROP was 485.67 +/- 158.73 mu g/l, in controls 389.9 +/- 102.8 mu g/l ( not significant), in RBC 109.50 +/- 117.89 mu g/l, in WRBC 61.07 +/- 30.0 mu g/ l. Except for IGFBP-3 other IGFBPs were barely or not detectable in RBC or WRBC. Conclusions: Considering lower IGF-1 concentrations in preterm infants than in adults ( factor 20), the IGF-1 in RBC transfusions is equivalent to a single dose of 1 mu g/kg IGF-1 (5-10% of the adult dose with proved metabolic responses). Endocrinological relationships between the donor's load and the acceptor's individual features are a new aspect of potential side effects of RBC transfusions. Further research is necessary to clarify the share of the described IGF administration on the development of ROP. Copyright (C) 2006 S. Karger AG, Basel.