Links between plasma 8-hydroxy-2'-deoxyguanosine(8-OHdG）and various parameters in hemodialysis patients

Objectives: Hemodialysis patients are exposed to various oxidative stress conditions, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) is a marker of oxidative DNA stress. Here, we measured plasma 8-OHdG in patients undergoing maintenance hemodialysis, and then investigated its relationships with the geriatric nutritional risk index (GNRI), nutritional status via albumin, etc., inflammatory markers such as CRP and interleukin-6 (IL-6), as well as the arteriosclerosis-related factor fetuin-A, contributions to renal anemia, and erythropoiesis-stimulating agent (ESA) quantities used. Subjects：138 patients were undergoing stable maintenance hemodialysis. Of these, 95 were men, and 43 women, with a mean age of 69±11 (38 to 88 years) and a mean dialysis history of 58±60 months (3 to 390 months). Methods: 8-OHdG was measured with a high sensitivity enzyme-linked immunosorbent assay (ELISA). Moreover, IL-6 and fetuin-A were also measured with ELISA. GNRI was calculated with the formula proposed by Bouillanne et al., and modified by Yamada et al. Correlations between blood biochemistry tests for hemoglobin (Hb), hematocrit (Hct), albumin, calcium (Ca), inorganic phosphorus (P), parathyroid hormone (intact-PTH), CRP, urea clearance (Kt/V), PCR, the ESA quantity used, and dialysis duration were comparatively investigated. Results: In investigations of 8-OHdG in men and women, significantly higher values were noted in women (p<0.05), with 0.26±0.08ng/mL for men and 0.29±0.09ng/mL for women. Moreover, a significant positive correlation of the patients' 8-OHdG with age was noted (p<0.005). Furthermore, a significant negative correlation was observed with the nutritional evaluation index and serum albumin (p<0.0001), and a significant negative correlation with GNRI was also noted (p<0.0001). Meanwhile, a significant positive correlation was observed with the inflammatory marker CRP (p<0.0001), and a significant positive correlation with IL-6 was also noted (p<0.0001). However a significant correlation with the arteriosclerosis-related marker, fetuin-A, was not observed. While no correlative relationship with BUN was noted, a significant negative correlation with creatinine was observed (p<0.05). When investigating relationships between 8-OHdG and ESA quantities used, as well as ESA to Hb ratios, a trend toward more ESA being used as 8-OHdG rose was noted, although significant correlations were not identified. However, a positive correlation with the erythropoietin resistance index (ERI) was observed. Conclusions: Plasma 8-OHdG, a marker of oxidative DNA stress, reflects the nutritional status and chronic inflammation in dialysis patients, and can be an index of erythropoietin resistance.