Differential accumulation of advanced glycation end products in the course of diabetic retinopathy

H. P. Hammes, A. Alt, T. Niwa, J. T. Clausen, R. G. Bretzel, M. Brownlee, E. D. Schleicher

Research output: Contribution to journalArticlepeer-review

181 Scopus citations

Abstract

Aims/hypothesis. Glycated proteins, formed by reaction of glucose and protein, react further yielding numerous, mostly undefined advanced glycation end products (AGE). The recently characterized imidazolone-type AGE (AG-1) is non-oxidatively formed involving 3-deoxyglucosone whereas some AGEs, particularly N(ε)-(carboxymethyl)lysine (CML), are formed only in the presence of oxygen. Methods. To study the possible contribution of oxidative and non-oxidative AGE formation in the development of diabetic retinopathy antibodies directed against CML-type and imidazolone-type AGEs were characterized by dot blot analysis and used to localize these well- characterized epitops in the retinas from diabetic rats (early course) and from human Type I (insulin-dependent) diabetes mellitus with laser-treated proliferative diabetic retinopathy (late course). Results. In non-diabetic rats CML was moderately positive in neuroglial and vascular structures of non-diabetic rat retinas and increased strongly in diabetic retinas. Anti- imidiazolone antibody staining was strongly positive only in diabetic capillaries. Advanced human diabetic retinopathy showed strong CML- immunolabelling of the entire retina whereas control samples showed moderate staining of neuroglial structures only with the polyclonal CML-antibody. Anti-imidiazolone antibody staining was faint in the inner retina of control sections but were strong throughout the entire diabetic retina. Immunolabelling for the AGE-receptor was congruent with a marker of Muller cells. Conclusion/interpretation. Our data indicate that the oxidatively formed CML is present in non-diabetic retinas as a regular constituent but increases in diabetes both in neuroglial and vascular components. Imidazolone-type AGE are restricted to microvessels and spread during later stages over the entire retina, co-localizing with the expression of AGE- receptor.

Original languageEnglish (US)
Pages (from-to)728-736
Number of pages9
JournalDiabetologia
Volume42
Issue number6
DOIs
StatePublished - 1999

Keywords

  • Advanced glycation end products
  • Carboxymethyllysine
  • Extracellular matrix
  • Oxidative stress
  • Retinopathy

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism

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