Adsorption Dialysis: From Physical Principles to Clinical Applications

Abstract

The uremic syndrome is characterized by the retention of various solutes that would normally be excreted by the kidneys. The substances that interact negatively with biologic functions are called uremic toxins. Over the past five decades, the membranes used for the treatment of chronic kidney disease have continuously evolved. The exposure of blood to any extracorporeal artificial surface results in the activation of several pathways within the body, including those involving coagulation and complement activation. One of the by-products of this generalized activation process is protein adsorption to the membrane surface, another phenomenon which can have a significant impact on solute removal. In fact, an array of studies showed that with increasing size of middle-sized proteins and other compounds, relatively more clearance is achieved by membrane adsorption compared with loss into the dialysate. A high adsorptive capacity, one of the main features of polymethylmethacrylate (PMMA) membranes, is very helpful and may both increase the total amount of solutes removed and remove different kinds of solutes. In this setting, a few studies have shown a variety of efficient clinical implications for adsorption hemodialysis, such as uremic pruritus, anemia, carpal tunnel syndrome and renal amyloidosis, immune dysfunction and improved response to vaccination. In addition, nutrition and survival were also improved using PMMA membranes.

UPLC-QTOF MS-Based Serum Metabolomic Profiling Analysis Reveals the Molecular Perturbations Underlying Uremic Pruritus

“…In the present study, the pattern of uremic toxins was disturbed in UP patients, which is consistent with the literature. Uremic syndrome is characterized by the retention of various solutes that would normally be excreted by the kidneys [ 15 ]. These uremic solutes have been reported to activate itch fibers, including the profound changes that occur with hyperparathyroidism-associated metabolic bone disease, increased systemic inflammation, and structural alterations in the skin related to dehydration and immune dysregulation of uremia [ 16 ].…”

Effect of dialyzer membrane materials on survival in chronic hemodialysis patients: Results from the annual survey of the Japanese Nationwide Dialysis Registry

“…HPM dialyzers have much higher biocompatibility and eliminate solutes that cannot otherwise be eliminated by conventional dialyzers, thus, they are predicted to have favorable long-term clinical outcomes for hemodialysis patients. These include improved prognosis, and ameliorating conditions like malnutrition, DRA-associated syndromes, renal anemia, pruritus, and restless leg syndrome [ 30 – 34 ]. Several dialyzers currently in use can efficiently eliminate low-molecular-weight proteins; in Japan, the standard definition for HPM dialyzers is those membranes providing β2M clearance of at least 10 mL/min in actual clinical use [ 1 , 5 ].…”

Choosing a dialyzer: What clinicians need to know

“…Toray Industries (Tokyo, Japan) developed a Polymethylmethacylate (PMMA) membrane with a homogeneous rather than asymmetric pore structure designed to increase middle molecule adsorption . Reports using this dialyzer have suggested better humoral immunity, greater clearance of free light chains, and response to erythropoietins, reduced pruritis, adsorption of intact parathyroid hormone, and preservation of muscle mass . However, it is important to note that although adsorption may improve middle molecular weight clearance, there will be a reduction in diffusional and convective clearance due to increased membrane protein deposition.…”