Vitreal insulin-like growth factor binding proteins (IGFBPs) are increased in human and animal diabetics

Robert J. Waldbillig, B. Eric Jones, Timothy J. Schoen, Payman Moshayedi, Scott Heidersbach, Milad S. Bitar, Frederik J.G.M. van Kuijk, Eugene De Juan, Peter Kador, Gerald J. Chader

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35 Scopus citations

Abstract

Although patients with diabetic retinopathy have been reported to have elevated vitreal IGF-I levels, it is not known whether diabetes also affects the levels of vitreal IGF binding proteins (IGFBPs) which control IGF's bioavailability. To address this issue, vitreal IGFBP levels were assayed in human diabetics, rats with streptozotocin-induced diabetes and galactose-fed dogs with diabetic-like retinopathy. Using 125I-IGF-II ligand blots, it was found that human diabetics have a 4-fold increase in vitreal IGFBP levels. Also, western blots on human diabetic vitreous reveal increased levels of IGFBP-2 and proteolytic fragments of IGFBP-3. IGF binding assays on vitreous from streptozotocin-treated rats (three months in duration) also indicate a 5-fold increase in IGF binding activity. IGF ligand blots using vitreous from rats with a shorter duration of diabetes (one month) show a 63% increase in IGFBP binding and a marked decrease in serum IGFBP binding. IGF ligand blots and IGFBP-2 and -4 western blots using vitreous from galactose-fed dogs with diabetic-like retinopathy exhibit a 6-fold increase in vitreal IGFBPs. The observation that vitreal IGFBPs are elevated in diabetic humans and rats without overt retinopathy suggests that these increases are not the result of a preexisting end-stage retinopathy but rather are an early ocular event in the diabetic process. Increases in vitreal IGFBPs thus could participate in the proliferative aspects of diabetic retinopathy by virtue of their putative intrinsic bioactivity or their capacity to alter IGF bioavailability.

Original languageEnglish (US)
Pages (from-to)539-546
Number of pages8
JournalCurrent Eye Research
Volume13
Issue number7
DOIs
StatePublished - Jan 1 1994

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Keywords

  • Diabetic retinopathy
  • Galactosemia
  • Insulin-like growth factor (IGF)
  • Insulin-like growth factor binding proteins (IGFBPs)
  • Retina
  • Streptozotocin
  • Vitreous humor

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Waldbillig, R. J., Jones, B. E., Schoen, T. J., Moshayedi, P., Heidersbach, S., Bitar, M. S., van Kuijk, F. J. G. M., Juan, E. D., Kador, P., & Chader, G. J. (1994). Vitreal insulin-like growth factor binding proteins (IGFBPs) are increased in human and animal diabetics. Current Eye Research, 13(7), 539-546. https://doi.org/10.3109/02713689408999886