Future Avenues to Decrease Uremic Toxin Concentration.

In this article, we review approaches for decreasing uremic solute concentrations in chronic kidney disease and in particular, in end-stage renal disease (ESRD). The rationale to do so is the straightforward relation between concentration and biological (toxic) effect for most toxins. The first section is devoted to extracorporeal strategies (kidney replacement therapy).

Vitamin D binding protein and the need for vitamin D in hemodialysis patients.

Objective: Vitamin D binding protein (DBP) is a polymorphic serum protein with a predominant role in a spectrum of biological activities. Chronic renal failure is characterized by deficient vitamin D metabolism. The present study investigates the impact of DBP polymorphism on the need for vitamin D in hemodialysis patients.

Impact of iron sucrose therapy on leucocyte surface molecules and reactive oxygen species in haemodialysis patients.

Background: It has been suggested that iron increases oxidative stress and that an excess of iron contributes to cardiovascular disease and infections in haemodialysis patients. In the present study, the effects of parenterally administered iron on leucocyte surface molecule expression and the production of reactive oxygen species (ROS) were evaluated.

Methods: Ten chronic haemodialysis (HD) patients without iron overload were studied.

In vitro study of the potential role of guanidines in leukocyte functions related to atherogenesis and infection.

Background: The blunted immune response upon stimulation in chronic renal failure (CRF) is often coupled to a baseline inflammatory status which has been related to atherogenesis. Uremic biologic fluids and several specific uremic retention solutes alter cell-mediated immune responses, as well as the interaction of calcitriol with the immune system.

Methods: The present study evaluated the influence of different guanidino compounds on DNA synthesis, chemiluminescence production, and CD14 expression of undifferentiated and calcitriol-differentiated HL-60 cells.

Uremic toxins: removal with different therapies.

A convenient way to classify uremic solutes is to subdivide them according to the physicochemical characteristics influencing their dialytic removal into small water-soluble compounds (<500 Da), protein-bound compounds, and middle molecules (>500 Da). The prototype of small water-soluble solutes remains urea although the proof of its toxicity is scanty. Only a few other water-soluble compounds exert toxicity (e.

An overview of uremic toxicity.

About 100 uremic retention solutes have been identified at present, but not all of these compounds are necessarily toxic. They can be defined as uremic toxins if they exert biochemical/biological actions. Based on their physicochemical characteristics, there are three major groups of uremic retention solutes: 1) the small water-soluble compounds (<500 Da), which are easily removed by standard low-pore-size dialyzer membranes; 2) the protein-bound solutes (also mostly <500 Da), whose dialytic removal is hampered by their protein binding, irrespective of the membrane type; and 3) the so-called middle molecules (>500 Da), which can be removed only by membranes with a large pore size and/or adsorptive capacity.

Studies on dialysate mixing in the Genius single-pass batch system for hemodialysis therapy.

Background: The Genius single-pass batch system for hemodialysis contains a closed reservoir and dialysate circuit of 75 L dialysate. The unused dialysate is withdrawn at the top of the reservoir and the spent fluid is reintroduced into the container at the bottom. Although it has been claimed that both fractions remain unmixed during the dialysis session, no direct proof of this assumption has yet been provided.

Back to the future: middle molecules, high flux membranes, and optimal dialysis.

Middle molecules can be defined as compounds with a molecular weight (MW) above 500 Da. An even broader definition includes those molecules that do not cross the membranes of standard low-flux dialyzers, not only because of molecular weight, but also because of protein binding and/or multicompartmental behavior. Recently, several of these middle molecules have been linked to the increased tendency of uremic patients to develop inflammation, malnutrition, and atheromatosis.