Wednesday, August 3, 2011

Chromium 3 results in permanent modification to DNA in MoM hip? (6 of 6.) What does this mean?

I would like to understand what it means when they say that "direct binding of Cr3 to DNA is well documented" and why this matters to us as patients.
  • Wolf et al 1989 
  • Landon et al 2004
  • Bacon et al 1983
  • Martnett et al 1999
  • Hartwig et al 2003
  • Witkiewicz-Kucharczyk and Bal 2006
I will explore this in a series of 6 posts

Final post on metal-induced intracellular effects

Landon investigated changes in metal ion levels and chromosome aberrations in patients within 3 years of receiving the Metal on metal hip artheroplasties.  The authors noted an increase in chromosome translocations* and aneuplody** in periperheral blood lymphocytes at 6, 12 and 24 mos post surgery.  They also noted the changes were progressive.  The authors didn't find any statistically significant  correlations between chromosomal translocation indices and Co or Cr concentrations in whole blood.

*chromosome translocations-In genetics, a chromosome translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. A gene fusion may be created when the translocation joins two otherwise separated genes, the occurrence of which is common in cancer.

**aneuploidy-Aneuploidy is an abnormal number of chromosomes, and is a type of chromosome abnormality. An extra or missing chromosome is a common cause of genetic disorders (birth defects). Some cancer cells also have abnormal numbers of chromosomes.[1]


J Arthroplasty. 2004 Dec;19(8 Suppl 3):78-83.

Changes in metal levels and chromosome aberrations in the peripheral blood of patients after metal-on-metal hip arthroplasty.

Source

University of Bristol, Orthopaedic Surgery, BIRC-Bristol Implant Research Center, Bristol, UK.

Abstract

A prospective study was performed to investigate changes in metal levels and chromosome aberrations in patients within 2 years of receiving metal-on-metal hip arthroplasties. There was a statistically significant increase of cobalt and chromium concentrations, with a small increase in molybdenum, in whole blood at 6, 12, and 24 months after surgery. There was also a statistically significant increase of both chromosome translocations and aneuploidy in peripheral blood lymphocytes at 6, 12, and 24 months after surgery. The changes were generally progressive with time, but the change in aneuploidy was much greater than in chromosome translocations. No statistically significant correlations were found in secondary analyses between chromosome translocation indices and cobalt or chromium concentration in whole blood. Although the clinical consequences of these changes, if any, are unknown, future epidemiological studies could usefully include direct comparisons of patients with implants of different composition.

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