Serum albumin fragmentation in end-stage renal disease patients a pilot study.

Background: The goal of this study was to detect modification in the expression of plasma proteins and/or post-translational modifications of their structure in patients with end stage renal disease. Methods: Serum samples from 19 adult patients treated by maintenance hemodialysis (MHD) were analyzed in comparison to sera from six healthy controls using sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2DE). Spots of interest were identified by mass spectrometry analysis. In addition, the 2DE maps were incubated with a human anti-albumin polyclonal antibody. Results: SDS-PAGE gels, 2DE maps and matrix-assisted laser desorption/ionization time of flight analysis indicated over-expression of low-molecular weight proteins (LMWP) in sera from patients. Unexpectedly, another 15 spots with estimated Mr of 12.5–29 kDa from the 2DE maps of six patients were identified as fragments of albumin. 2D immunoblotting of sera from 12 other patients detected numerous albumin fragments. Conclusions: These results indicate that in addition to increased expression of LMWP, a relevant amount of albumin fragments are detectable in the serum of patients undergoing MHD. Uremia appears to facilitate the fragmentation of albumin and/or the retention of albumin fragments in blood.