Diacap ® α-Polysulfone HI PS: a New Dialysis Membrane with Optimum β 2 -Microglobulin Elimination

Abstract

Background

Plasma concentration of β₂-microglobulin (β₂-m) in the case of renal insufficiency is about 20 to 30 times higher than normal. β₂-m is associated with secondary amyloidosis, a late complication of regular dialysis therapy. To prevent the complications of secondary amyloidosis β₂-m should therefore be eliminated as efficiently as possible during dialysis treatment. This can be accomplished with dialysis membranes which guarantee sufficient clearance for this molecule. It is a matter of discussion whether removal of β₂-m by dialysis may be able to prevent secondary amyloidosis.

Methods

The dialyzers Diacap HI PS 15 (B. Braun Melsungen) and F70 S (Fresenius Medical Care) were compared in five anuric dialysis patients. Arterial blood was taken at the start and at the end of dialysis. Dialysate samples were taken after 30 and 210 minutes and filtrate samples after 60 and 240 minutes from the start of dialysis. β₂-m and total protein concentration were measured in plasma, filtrate and dialysate. SDS-PAGE of proteins in the filtrate was carried out and kinetics of β₂-m (Kt/V_β2-m) were calculated using the Stiller/Mann model (4, 5).

Results

In both dialyzers β₂-m is detectable at any time in the dialysate leaving the dialyzer. In the filtrate β₂-m concentration is about 10 times higher than in the dialysate. Protein pattern in filtrate of both dialyzers is similar and corresponds to that of the glomerulum filtrate. β₂-m reduction ratio is slightly lower than urea reduction ratio. Using both dialyzers Kt/V_β2-m was 0.80, removing about 60% of the generated β₂-m.

Conclusions

In both dialyzers there is considerable removal of β₂-m. Examination of β₂-m kinetics showed an optimum of Kt/V_β2 of 0.80 which can not be surpassed. Only 60% of generated β₂-m can be removed by three times per week hemodialysis therapy using high-flux dialyzers.