Investigation of the binding of Cr(III) complexes to bovine and human serum proteins: a proteomic approach.

Chromium (Cr) compounds are widely used in alloys manufacturing and forming processes. One of the main concerns in the use of cobalt-chromium (Co-Cr) alloy-based implants is the long-term fate of Co and Cr ions in the blood, organs, and urine of patients. Our previous studies have shown that Cr(III) forms complexes in different cell culture media, whereas Cr(VI) does not form any detectable structure under the same conditions. Because Cr(VI) is known to be more toxic than Cr(III), we hypothesized that the presence of serum proteins in the molecular structure of Cr(III) may be responsible for the difference in toxicity. We investigated the interaction of the Cr(III) complexes with serum proteins and their internalization by U937 macrophage-like cells. By using a proteomic approach, we showed that in the presence of fetal bovine serum, Cr(III) complexes interacted only with albumin, whereas they interacted mainly with albumin, transferrin, and immunoglobulins (Ig) in the presence of human serum (HS). Cr(III) complexes were more easily engulfed by U937 macrophage-like cells when they were formed with HS. To the best of our knowledge, this is the first report on the formation of Cr(III) complexes in the presence of serum proteins and the interaction of these complexes with U937 macrophage-like cells. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.