Coagulation and fractionated plasma separation and adsorption

Improving Solute Clearances by Hemodialysis

The adequacy of hemodialysis is now assessed by measuring the removal of the single-solute urea. The urea clearance provided by contemporary dialysis is a large fraction of the blood flow through the dialyzer and therefore cannot be increased much further. Other solutes however likely contribute more than urea to the residual uremic illness suffered by hemodialysis patients. We here review methods which could be employed to increase the clearance of nonurea solutes. We will separately consider the clearances of free low-molecular-mass solutes, free larger solutes, and protein-bound solutes. New clinical studies will be required to test the extent to which increasing the clearance on nonurea solutes with these various characteristics can improve patients' health.

Improving Clearance for Renal Replacement Therapy

The adequacy of hemodialysis is now assessed by measuring the removal of a single solute, urea. The urea clearance provided by current dialysis methods is a large fraction of the blood flow through the dialyzer, and, therefore, cannot be increased much further. However, other solutes, which are less effectively cleared than urea, may contribute more to the residual uremic illness suffered by patients on hemodialysis. Here, we review a variety of methods that could be used to increase the clearance of such nonurea solutes. New clinical studies will be required to test the extent to which increasing solute clearances improves patients' health.

an Obituary for GFR as the main marker for kidney function?

This publication comments on the recently published findings of a study by Eloot et al. (cJASN, 6: 1266-1273, 2011) that evaluated the correlation between several formulae for calculating estimated GFR (eGFR) and different low molecular weight uremic toxins; eGFRs were based on serum creatinine (SCrea), cystatin C (Cys C), or a combination of both. Unexpectedly, the correlations for the different solutes were highly inconsistent, irrespective of the eGFR formula. On the other hand, the different eGFR formulae gave consistent results per solute. Correlation coefficients for some solutes were low (hippuric acid, p-cresylsulfate, indole acetic acid, uric acid, asymmetric dimethylarginine) to nonsignificant (carboxy-methyl-propyl-furanpropionic acid). These data point to the fact that eGFR is a deceiving predictor of uremic solute concentration and their biological action; this inconsistency is very likely the result of the impact of other factors affecting concentration, such as tubular secretion, generation by intestinal flora and metabolism.