Baseline and oxidatively damaged DNA in end-stage renal disease patients on varied hemodialysis regimens: a comet assay assessment

Global estimates exhibit that one million people have end-stage renal disease, a disease-state characterized by irreversible loss of kidney structure and function, thus necessitating renal replacement therapy. The disease-state, oxidative stress, inflammatory responses, as well as the treatment procedure can have damaging effects on the genetic material. Therefore, the present study was carried out to investigate DNA damage (basal and oxidative) using the comet assay in peripheral blood leukocytes of patients (n=200) with stage V Chronic Kidney Disease (on dialysis and those recommended but yet to initiate dialysis) and compare it to that in controls (n=210). Basal DNA damage was significantly elevated (1.13x, p <= 0.001) in patients (46.23 +/- 0.58% DNA in tail) compared to controls (40.85 +/- 0.61% DNA in tail). Oxidative DNA damage was also significantly (p <= 0.001) higher in patients (9.18 +/- 0.49 vs. 2.59 +/- 0.19% tail DNA) compared to controls. Twice-a-week dialysis regimen patients had significantly elevated % tail DNA and Damage Index compared to the non-dialyzed and to the once-a-week dialysis group implying dialysis- induced mechanical stress and blood-dialyzer membrane interactions as probable contributors to elevated DNA damage. The present study with a statistically significant power implies higher disease-associated as well as maintenance therapy (hemodialysis)-induced basal and oxidatively damaged DNA, which if not repaired has the potential to initiate carcinogenesis. These findings mark the need for improvement and development of interventional therapies for delaying disease progression and associated co-morbidities so as to improve life expectancy of patients with kidney disease.