Can cytokines be removed by hemofiltration or hemoadsorption?

Area of Science:

• Nephrology
• Biomedical Engineering
• Immunology

Background:

• Pro-inflammatory cytokines play a key role in various inflammatory conditions.
• Hemofiltration (HF) is a blood purification technique used to remove solutes from the blood.
• Understanding cytokine removal during HF is crucial for optimizing treatment strategies.

Purpose of the Study:

• To investigate the efficiency of different high-flux membranes (HFM) in removing pro-inflammatory cytokines: tumor necrosis factor-alpha (TNFα), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6) during experimental hemofiltration.
• To explore potential removal mechanisms beyond simple filtration, such as adsorption.

Main Methods:

• Experimental hemofiltration was conducted using a closed-circuit system with monocyte-free human plasma spiked with TNFα, IL-1β, and IL-6.
• Plasma and filtrate samples were collected over 4 hours and analyzed for cytokine concentrations using enzyme-linked immunosorbent assay (ELISA).
• Various high-flux membranes (PAN, CTA, PMMA, PS) and a charcoal adsorbent column (HA) were tested.

Main Results:

• Interleukin-1 beta (IL-1β) demonstrated high removal rates across tested HFM, with varying efficiencies (PAN>CTA>PMMA>PS).
• Tumor necrosis factor-alpha (TNFα) and interleukin-6 (IL-6) showed minimal filtration through HFM. Some TNFα removal was observed with PS membranes, and partial IL-6 removal with PMMA membranes, suggesting adsorption.
• A charcoal adsorbent column (HA) effectively removed IL-1β and IL-6, particularly within the first 2 hours, while TNFα removal was partial.

Conclusions:

• High-flux membranes are effective for removing IL-1β during hemofiltration.
• The removal of TNFα and IL-6 by hemofiltration using standard HFM is limited, necessitating alternative or complementary strategies.
• Adsorption techniques, particularly using charcoal, show promise for enhancing the removal of IL-6 and partially TNFα in hemofiltration circuits.