FLUORESCENCE AND IMMUNOCHEMICAL STUDIES OF ADVANCED GLYCATION-RELATEDLENS PIGMENTS

PURPOSE. TO establish whether advanced glycation is the major mechanis m for yellowing of lens proteins. METHODS. Synchronous fluorescence (S F) and immunochemical assays were used to study glycation in vitro and in vivo. In the in vitro study, advanced glycation end products (AGEs ) were prepared and used as antigens to induce antibodies to AGEs. The in vitro AG-Es and classified nuclear cataracts were analyzed by SF a nd immunochemical assays. RESULTS. In vitro AGEs generated from variou s glycating agents and carrier proteins displayed strong SF above 350 nm; the spectra were well resolved with major bands at 380 nm and 420 nm. Samples from human lenses manifested a band at 395 nm in addition to the two bands shown by in vitro AGEs. SF intensity is greater for t he water-insoluble (WI) than water-soluble (WS) fraction, but both inc reased with increasing nuclear color. The immunoreactivity data also s howed that the WI fraction contained more AGEs than the WS fraction an d that the amount of AGEs increased with increasing nuclear color. CON CLUSIONS. Fluorescence and immunoassays indicated that pigmented AGEs contributed to yellowing of the crystalline lens nucleus.