Increased levels of advanced glycation end products in human cataractous lenses.
OBJECTIVE
To investigate the occurrence of advanced glycation end products (AGEs) formed oxidatively (pentosidine and N(epsilon)-carboxymethyl lysine [CML]) or nonoxidatively (imidazolone) in human lenses and the relation of AGEs to lens coloration, cataract type, and patients' diabetic state.


METHODS
Departments of Ophthalmology and Internal Medicine III, University of Jena, Jena, Germany.


METHODS
Pentosidine, CML, and imidazolone concentrations were measured in the water-soluble protein fraction of 44 cataractous lenses (from 24 nondiabetic and 20 diabetic donors) and 6 noncataractous control lenses.


RESULTS
Pentosidine, CML, and imidazolone were higher in cataractous lenses than in control lenses (pentosidine, 3.7 pmol/mg +/- 5.3 (SD) and 1.9 +/- 1.7 pmol/mg, respectively; CML, 3.0 +/- 2.2 nmol/mg and 1.3 +/- 0.7 nmol/mg, respectively; imidazoline, 80.4 +/- 93.3 AU/mg and 19.6 +/- 18.5 AU/mg, respectively). Among the cataractous lenses, the highest AGE concentrations were found in mature cataracts, with a statistically significant increase in CML. The AGE content increased relative to the intensity of brown coloration of the lens; the brown coloration also indicated the highest rise of imidazolone compared to pentosidine and CML. Lenses from diabetic donors had generally similar pentosidine values and elevated CML and imidazolone levels compared to lenses from nondiabetic donors. The pentosidine, CML, and imidazolone levels in the lenses correlated significantly with one another but not with patient age.


CONCLUSIONS
Advanced glycation end products formed oxidatively and nonoxidatively occurred to a higher degree in cataractous lenses than in noncataractous lenses. The strong relationship between the lenses' AGE content, color/opacity, and the state of the cataract may indicate that advanced glycation plays a pivotal role in cataract formation.
Franke
Sybille
S
Department of Internal Medicine III, Friedrich Schiller University of Jena, 07740 Jena, Germany. sybille.franke@med.uni-jena.de
Dawczynski
Jens
J
Strobel
Jürgen
J
Niwa
Toshimitsu
T
Stahl
Peter
P
Stein
Günter
G
D000368:Aged; D000911:Antibodies, Monoclonal; D001120:Arginine / Q000031:analogs & derivatives* / Q000378:metabolism; D002386:Cataract / Q000145:classification / Q000378:metabolism* / Q000473:pathology; D003920:Diabetes Mellitus / Q000378:metabolism*; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000378:metabolism; D007124:Immunoenzyme Techniques; D007908:Lens, Crystalline / Q000378:metabolism* / Q000473:pathology; D008239:Lysine / Q000031:analogs & derivatives* / Q000378:metabolism; D008875:Middle Aged; D010084:Oxidation-Reduction
D000911:Antibodies, Monoclonal; D017127:Glycation End Products, Advanced; D007093:Imidazoles; C117197:imidazolone; C048496:N(6)-carboxymethyllysine; D001120:Arginine; C062187:pentosidine; D008239:Lysine