MODIFICATION OF BETA(2)M WITH ADVANCED GLYCATION END-PRODUCTS AS OBSERVED IN DIALYSIS-RELATED AMYLOIDOSIS BY 3-DG ACCUMULATING IN UREMIC SERUM

beta(2)microglobulin (beta(2)m) isolated from the amyloid deposits in patients with dialysis-related amyloidosis (DRA) has been demonstrated to be modified with advanced glycation end products (AGEs). We demons trated that AGE was localized to amyloid deposits in patients with DRA by immunohistochemistry using a monoclonal anti-AGE antibody. To clar ify the mechanism of AGE modification of beta(2)m-amyloid, we studied the effects of 3-deoxyglucosone (3-DG), a potent protein crosslinking intermediate of the Maillard reaction, on the AGE modification of beta (2)m, and quantified the serum levels of 3-DG in patients undergoing h emodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD), and undialyzed patients. The serum levels of 3-DG were markedly incre ased in the dialyzed and undialyzed uremic patients. Although the seru m level of 3-DG decreased after HD with a mean reduction rate of 67%, it was still significantly higher than in normal serum. Incubation of beta(2)m with 3-DG at 37 degrees C emitted fluorescence characteristic for AGE, and caused AGE modification and dimer formation of beta(2)m as demonstrated by Western blotting using the same monoclonal anti-AGE antibody used for immunohistochemical demonstration of AGE in DRA. Th e AGE-modified dimer of beta(2)m could be extracted from the amyloid t issue of a patient with DRA. 3-DC showed more intense and faster react ivity with beta(2)m to form AGE and dimer as compared with glucose, an d aminoguanidine suppressed the AGE and dimer formation of beta(2)m by 3-DG. In conclusion, 3-DG accumulating in uremic serum may be involve d in the AGE modification of beta(2)m-amyloid.