Selenium Depletion in Hemodialysis Patients Treated with Polysulfone Membranes

Abstract

Background/Aims: Epidemiological, animal and human studies have indicated that selenium deficiency is a risk factor for death from malignant diseases. The mechanisms that could modify selenium status may, therefore, be of particular interest in hemodialysis patients, considering their high cancer mortality rates. We aimed at evaluating the effect of hemodialysis with polysulfone membranes on selenium status. Methods: Twenty- eight chronically dialyzed patients and 32 age-matched healthy controls were enrolled in the study. Serum and dialysis fluid selenium concentrations, serum total protein, and hemoglobin concentrations and serum glutathione peroxidase activity were determined before and after the hemodialysis procedure. Results: The (mean ± SD) serum selenium and total protein concentrations and glutathione peroxidase activities were significantly (p < 0.05) higher in healthy controls (75.9 ± 8.3 µg/l, 78 ± 6 g/l, and 23.8 ± 4.8 mU/20 µl, respectively) than in the patients. There was no significant difference between serum selenium concentration before (63.6 ± 11.6 µg/l) and after (64.4 ± 11.4 µg/l) hemodialysis sessions, although hemoglobin and total serum protein concentrations and serum glutathione peroxidase activities increased (from 98.5 ± 1.3 to 114.8 ± 1.5 g/l, from 64 ± 8 to 71 ± 9 g/l, and from 16.8 ± 1.8 to 18.9 ± 1.9 mU/20 µl, respectively) significantly (p < 0.05) during hemodialysis, indicating hemoconcentration. The selenium concentration doubled, and protein appeared in the dialysates during dialysis session. The correlation of the selenium concentrations with the protein concentrations in the dialysate is significant (p < 0.01) with a Spearman R value of 0.97. Conclusion: The results of the present study suggest that selenium is lost through the pores of polysulfone membranes during hemodialysis which is associated with their protein permeability.

The Role of Dialysis Membranes on Intradialytic Selenium Removal and on Selenium Status in Patients Receiving Renal Replacement Therapy

“…Se loss was found only with polysulfone, likely due to large membrane pores [8] , and not with low-flux regenerated cellulosic membrane not allowing the passage of high molecular weight Se-binding proteins [13] .…”

“…Although some studies have reported normal pre-dialysis serum Se levels [13,14] , in the majority of studies, low pre-dialysis serum Se levels have been observed in patients on standard HD, in line with our results in standard HD [3,4,9,15] . Unchanged post-dialysis serum Se levels reflect an intradialytic Se loss, which is compensated due to hemoconcentration [8] . In HDF patients, reduced post-dialysis serum Se levels provide evidence of a significantly greater Se removal into effluent solution [4] , which contributed to the more obvious decrease in post-dialysis serum Se levels.…”

“…There are only 2 studies where Se was determined in dialysis fluid in order to estimate the role of dialysis membranes on Se status in chronic HD [8,13] . Se loss was found only with polysulfone, likely due to large membrane pores [8] , and not with low-flux regenerated cellulosic membrane not allowing the passage of high molecular weight Se-binding proteins [13] .…”

“…Dialysis membrane and especially polysulfone permeability has been implicated in intradialytic Se loss and Se depletion in chronic HD [4,8] . Some authors suggest that Se supplementation could be a strategy for survival improvement in HD via antioxidant activity and cardioprotective effect of the element [9,10] .…”

Importance of selenium homeostasis in chronic and end-stage kidney diseases

“…Poliszulfon-membrán alkalmazása során a GSHP-aktivitás és a szelénkoncentráció szignifi kánsan csökkent a hemophan-membránnal kezelt betegekhez képest. Ennek alapján úgy tűnik, hogy a poliszulfon-membrán nagyobb oxidatív stresszt okozó hatású és jobban csökkenti a szelénszintet [62,63], de ennek ellentmondó vizsgálati eredményről is beszá-moltak [64].…”