Urinary 8-oxo-2 '-deoxyguanosine - Source, significance and supplements

Oxidative damage to cellular biomolecules, in particular DNA, has been prop osed to play an important role in a number of pathological conditions, incl uding carcinogenesis. A much studied consequence of oxygen-centred radical damage to DNA is 8-oxo-2'-deoxyguanosine (8-oxodG). Using numerous techniqu es, this lesion has been quantified in various biological matrices, most no tably DNA and urine. Until recently, it was understood that urinary 8-oxodG derives solely from DNA repair, although the processes which may yield the modified deoxynucleoside have never been thoroughly discussed. This review suggests that nucleotide excision repair and the action of a specific endo nuclease may, in addition to the nucleotide pool, contribute significantly to levels of 8-oxodG in the urine. On this basis, urinary 8-oxodG represent s an important biomarker of generalised, cellular oxidative stress. Current data from antioxidant supplementation trials are examined and the potentia l for such compounds to modulate DNA repair is considered. It is stressed t hat further work is required to link DNA, serum and urinary levels of 8-oxo dG such that the kinetics of formation and clearance may be elucidated, fac ilitating greater understanding of the role played by oxidative stress in d isease.