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Production and activation of matrix metalloproteinase-2 in proliferative diabetic retinopathy

Kousuke Noda1, Susumu Ishida, Makoto Inoue

  • 1Department of Pathology, Keio University School of Medicine, Toyama, Japan.

Investigative Ophthalmology & Visual Science
|April 26, 2003
PubMed
Abstract

Insights

Matrix metalloproteinases (MMPs) like MMP-2 and MMP-9 are elevated in proliferative diabetic retinopathy (PDR). ProMMP-2 activation occurs in PDR fibrovascular tissues, suggesting MMP-2 and MT1-MMP involvement in disease pathogenesis.

Area of Science:

  • Ophthalmology
  • Molecular Biology
  • Biochemistry

Background:

  • Proliferative diabetic retinopathy (PDR) is a severe complication of diabetes, characterized by abnormal blood vessel growth.
  • Matrix metalloproteinases (MMPs) are enzymes involved in tissue remodeling and are implicated in various pathological processes, including angiogenesis.

Purpose of the Study:

  • To investigate the specific matrix metalloproteinase (MMP) species and their activation states associated with the pathogenesis of proliferative diabetic retinopathy (PDR).

Main Methods:

  • Sandwich enzyme immunoassays were used to quantify MMP levels in vitreous samples.
  • Gelatin zymography assessed the activation ratios of proMMP-2 and proMMP-9.
  • Immunohistochemistry and RT-PCR examined the production, localization, and gene expression of MMP-2, MT1-MMP, TIMP-2, and MMP-9 in fibrovascular tissues.

Main Results:

  • MMP-2 and MMP-9 levels were significantly higher in PDR vitreous samples compared to controls.
  • Activation ratios of proMMP-2 and proMMP-9 in PDR vitreous were low.
  • Fibrovascular tissues showed high activation ratios for proMMP-2 and notable activation of proMMP-9, with MMP-2 colocalizing with its activator MT1-MMP and TIMP-2.

Conclusions:

  • ProMMP-2 is efficiently activated within the fibrovascular tissues of PDR, likely mediated by MT1-MMP and TIMP-2.
  • The activity of MMP-2 and MT1-MMP may play a crucial role in the neovascularization process characteristic of PDR.

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