Investigation of the effects of hemodialysis on renal biomarkers and oxidative stress

Fibroblast growth factor 23 (FGF23) is a bone-borne hormone that plays an important role in the pathogenesis of impaired mineral metabolism in chronic kidney disease. In this study, it was aimed to investigate the effect of hemodialysis on renal biomarkers, especially FGF23, 25 (OH) Vitamin D and parathormone (PTH), and to evaluate oxidative stress which is one of the complications of hemodialysis treatment. Twenty-five patients (11F: 14M, 62.92 ± 12.35 years) and 25 healthy subjects (10F: 15M, 56.68 ± 9.98 years) were included in this study. FGF23, vitamin D, parathormon (PTH) levels, renal function tests, total antioxidant status (TAS), total antioxidant capacity (TAC), total oxidant status (TOS), hemogram and blood gas parameters were examined in the patient (before and after hemodialysis) and control groups. Mean circulating FGF23 levels were measured 349.58 ± 207.79 pg/mL before the hemodialysis treatment, 403.56 ± 193.26 pg/mL after dialysis, and 338.20 ± 141.17 pg/mL in the control group. There was no difference between the groups (p>0.05). In the patient group, iPTH (intact PTH) levels were measured 293.70 (219.85-577.25) pg/mL before hemodialysis, 104.8 (60.05-280.70) pg/mL after hemodialysis and 47.40 (37.20-57.60) pg/mL in the control group. Significant difference between pre-hemodialysis and post-hemodialysis and patient (pre-hemodialysis)-control groups has been found (p<0.001). Vitamin D concentrations in the patient group did not change after hemodialysis (9.81 ± 3.97 ng / mL) compared to before hemodialysis (9.37 ± 3.97 ng /mL) (p> 0.05).Vitamin D levels measured in the control group as 14.38 ± 7.05 ng/mL was higher than the patient group (pre-hemodialysis) (p=0.004). While TOS levels were not changed after hemodialysis (p>0.05), TAC and TAS levels were increased (p<0.05). When the patient and control groups were compared, the TOS level was not changed between the two groups (p> 0.05). In the control group, it was found that the TAC value was higher and the TAS value was lower (p<0.05). As a result of this study, it was observed that FGF23 excretion did not change after hemodialysis but uric acid, urea, creatinine and phosphate excretion increased. It is thought that researches should be done to increase FGF23 clearance after hemodialysis. Moreover, it has been shown that total antioxidant concentration in serum after hemodialysis increases while oxidant stress does not change. Key words: FGF23, hemodialysis, mineral and bone metabolism, oxidative stress