Sorbents in acute renal failure and end-stage renal disease: middle molecule and cytokine removal.

Renal replacement therapy in acute renal failure (ARF) and chronic renal failure (end-stage renal disease; ESRD) has been based on the use of modifications of dialysis (continuous arteriovenous hemofiltration and hemodiafiltration) to remove middle-molecular-weight toxins, consisting of low-molecular-weight proteins and peptides (LMWP) and cytokines involved in inflammation. High-flux dialyzers are not efficient at removing LMWP, and for this reason, sorbents have been studied to augment or replace dialysis. Removal of LMWP such as beta2-microglobulin, leptin, complement factor D, angiogenin and cytokines such as interleukin (IL)-1, IL-6, IL-10, IL-18 and tumor necrosis factor-alpha has been established in animal models of sepsis and in ESRD patients using sorbents. Sorbent devices added to hemodialysis, or the use of such devices alone in inflammatory states, including sepsis, ARF, cardiopulmonary bypass, pre-explantation of donor organs and ESRD, are being studied.