Monday, August 22, 2011

Chromium induced Genotoxicity with BOTH Chromium 3 and Chromium 6

Often times, physicians dismiss the genotoxic effects (changes in DNA caused by the chromium from the hip) of the less toxic chromium 3 (trivalent chromium) which is purportedly the chromium in the hip. NOTE, CHROMIUM 3 IS LESS TOXIC THAN CHROMIUM 6 (hexavalent chromium).  THIS DOES NOT MEAN THAT ONLY CHROMIUM 6 IS A PROBLEM.

This study was just released.


J Toxicol Environ Health A. 2011 Aug;74(15-16):1030-9.

Chromium-induced genotoxicity and interference in human lymphoblastoid cell (TK6) repair processes.


Source

Grup de Mutagènesi, Departament de Genètica i de Microbiologia, Edifici Cn, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain.

Abstract

Two model chromium (Cr) compounds, one hexavalent (sodium chromate) and one trivalent (chromium chloride), were investigated in a human lymphoblastoid cell line (TK6) to increase our knowledge regarding Cr-induced genotoxicity mechanisms. Both selected compounds were genotoxic using the comet assay, although the percentage of DNA in tail obtained after treatment with Cr(VI) was significantly higher than that obtained with Cr(III), at the higher concentrations tested. To determine the nature of the induced damage, enzymes recognizing oxidized bases were used. Treatments with formamidopyrimidine (FPG) and endonuclease III (EndoIII) displayed a greater degree of DNA damage, indicating that the induction of oxidized bases accounts for an important proportion of the damage induced by Cr compounds. In addition, the kinetic repair studies showed that generated DNA damage is removed in approximately 8 h, with the damage induced by Cr(III) being removed/repaired more rapidly than damage produced by Cr(VI). To detect Cr interferences with the repair process, a post-treatment was applied after exposure to 2 Gy gamma radiation. Post-treatment significantly delayed the repair kinetics of DNA damage induced by radiation. This interference effect induced by Cr(VI) was more pronounced. In conclusion, evidence indicates that a high proportion of the Cr-induced DNA damage is correlated with oxidative damage, and that both Cr compounds interfere with repair mechanisms involved in repair of DNA damage induced by gamma radiation.

[genotoxicity is important because In genetics, genotoxicity describes a deleterious action on a cell's genetic material affecting its integrity. Genotoxic substances are known to be potentially mutagenic or carcinogenic, specifically those capable of causing genetic mutation and of contributing to the development of tumors.

This is a subject of great importance to me because I believe that patients get the idea that there is no issue with Chromium 3 contained in the Depuy hip.  This is not a true statement.  A true statement would reflect the clear uncertainty surrounding the question as to whether the genotoxicty question in chromium 3 is mutagenic or carcinogenic.  I have many many posts on this.  If you go to the home page and click on medical studies, and then scroll down the list, you can see them all.

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