Depletion of reactive advanced glycation endproducts from diabetic uremic sera using a lysozyme-linked matrix

J Clin Invest. 1997 Aug 15;100(4):847-54. doi: 10.1172/JCI119600.

Abstract

Diabetic uremic sera contain excessive amounts of reactive advanced glycation endproducts (AGEs), which accelerate the vasculopathy of diabetes and end-stage renal disease. To capture in vivo-derived toxic AGEs, high affinity AGE-binding protein lysozyme (LZ) was linked to a Sepharose 4B matrix. Initial studies showed that > 80% of 125I-AGE-BSA was retained by the LZ matrix, compared with < 10% retained by a control matrix. More than 60% of AGE-lysine was captured by the LZ matrix, and the LZ-bound fraction retained immunoreactivity and cross-linking activity, but had little intrinsic fluorescence (370/440 nm). After passage through the LZ matrix, AGE levels in diabetic sera (0.37+/-0.04 U/mg) were significantly reduced to a level (0.09+/-0.01 U/mg; n = 10; P < 0. 0001) comparable with the level of normal human serum, whereas total protein absorption was < 3%. The AGE-enriched serum fraction exhibited cross-linking activity, which was completely prevented by aminoguanidine. Among numerous LZ-bound proteins in diabetic uremic sera, three major proteins "susceptible" to AGE modification were identified: the immunoglobulin G light chain, apolipoprotein J (clusterin/SP-40,40), and the complement 3b beta chain. These findings indicate that the LZ-linked AGE affinity column may serve as an efficient method for the depletion of toxic AGEs from sera, including specific AGE-modified proteins that may be linked to altered immunity, lipoprotein metabolism, and accelerated vasculopathy in renal failure patients with or without diabetes.

MeSH terms

  • Adult
  • Aged
  • Amino Acid Sequence
  • Blood Proteins / pharmacology
  • Diabetic Nephropathies / blood*
  • Glycation End Products, Advanced / blood*
  • Glycation End Products, Advanced / chemistry
  • Humans
  • Immunoblotting
  • Middle Aged
  • Molecular Sequence Data
  • Muramidase / metabolism*
  • Serum Albumin, Bovine / metabolism
  • Uremia / blood

Substances

  • Blood Proteins
  • Glycation End Products, Advanced
  • Serum Albumin, Bovine
  • Muramidase