FORMATION OF CROSSLINE AS A FLUORESCENT ADVANCED GLYCATION END-PRODUCT IN-VITRO AND IN-VIVO

Crossline is one of the major advanced glycation end products resultin g the reaction mixture of free amino group(s) such as epsilon-one in l ysine with D-glucose in vitro. To study crossline formation on protein s in vitro and in vivo, polyclonal antiserum to the crossline hapten w as prepared. This antiserum reacted with bovine and human serum albumi n that had been modified by prolonged incubation with glucose as well as with crossline itself. Antisera did not react with unmodified serum albumin or the other Maillard-related compounds. Crossline was formed in a rime-dependent manner when a mixture of six different proteins w as incubated with glucose at pH 7.2 or 9.0. Crossline levels could be measured in rat lens proteins and the levels increased with age. The c rossline content of lens proteins in diabetic rats was more than two-f old higher than that of age-matched controls. Results of this study su ggest that most proteins containing advanced glycation end products ha ve crossline-like structures. Measurement of crossline-like structures in biological specimens may provide an index of aging and of the deve lopment of diabetic complications. (C) 1996 Academic Press, Inc.