Plasminogen activator inhibitor-1 overexpression in nonproliferative diabetic retinopathy

Maria B. Grant, E. Ann Ellis, Sergio Caballero, Robert N. Mames

Research output: Contribution to journalArticle

42 Scopus citations


Plasminogen activator inhibitor-1 is secreted bidirectionally by endothelial cells, acts as the primary regulator of fibrinolysis and as a key modulator of extracellular matrix proteolysis. Elevated farum levels of plasminogen activator inhibitor-1 are observed in serum of diabetic individuals. We investigated whether plasminogen activator inhibitor-1 is overexpressed in capillaries of diabetic donors with nonproliferative retinopathy compared to non-diabetic donors. We also assessed plasminogen activator inhibitor-1 expression in an animal model of retinopathy induced by exposing rabbit retinas to insulin-like growth factor-I. Colloidal gold immunocytochemistry was used to quantify plasminogen activator-1 antigen in donor retinas from diabetic subjects (n = 10) and control subjects (n = 10). This technique was also used to examine expression of plasminogen activator inhibitor-1 for correlation with retinal changes in the insulin-like growth factor-I-induced retinopathy model (n = 14). Plasminogen activator inhibitor-1 immunoreactivity was significantly increased in the retinas of all diabetic subjects as compared to controls. In the rabbit model, the expression of plasminogen activator inhibitor-1 immunoreactivity correlated with pathological retinal changes. In both the diabetic human and insulin-like growth factor-1-injected rabbit, overproduction of plasminogen activator inhibitor-1 was seen within the lumen of capillaries, within the cytoplasm of endothelial cells and in the basement membrane and extracellular matrix surrounding these capillaries. Minimal plasminogen activator inhibitor-1 was detected in the retinas of non-diabetics and in control rabbits injected with either heat-inactivated insulin-like growth factor-I or balanced salt solution. These studies support the conclusion that plasminogen activator inhibitor-1 is overexpressed in the retinal capillaries of diabetics with nonproliferative diabetic retinopathy and in rabbits with insulin-like growth factor-I-induced retinopathy.

Original languageEnglish (US)
Pages (from-to)233-244
Number of pages12
JournalExperimental eye research
Issue number3
StatePublished - Sep 1996


  • diabetic retinopathy
  • immunocytochemistry
  • insulin-like growth factor-I
  • plasminogen activator inhibitor
  • retinal endothelial cells

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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