Supplementary Material for: Direct Hemoperfusion with Polymethylmethacrylate for Hemodialysis Patients with Dialysis-related Amyloidosis

Introduction
Dialysis-related amyloidosis (DRA) is a serious complication in patients undergoing long-term dialysis that leads to conditions such as carpal tunnel syndrome and destructive spondyloarthropathy. Improved removal of the precursor protein β2-microglobulin (β2-m) is considered an effective treatment strategy for DRA. Polymethylmethacrylate (PMMA) membranes have the capacity to adsorb β2-m in dialysis filters, suggesting that direct hemoperfusion with PMMA in addition to standard dialysis may enhance β2-m removal.
Methods
This prospective cohort study included 10 patients undergoing hemodialysis, who were diagnosed with DRA. The participants were treated with dialysis filter alone during Visit 1, both standard dialysis filter and PMMA cartridges (FT-75, volume 75 cm³) during Visits 2–4, and FT-145 PMMA cartridges (volume 145 cm³) during Visits 5–7. The removal rates and clearances of β2-m were quantified. We also assessed the removal of α1-microglobulin (α1-m), matrix metalloproteinase-3 (MMP-3), interleukin-6 (IL-6), and tumor necrosis factor-a (TNF-α), which may be associated with DRA symptoms.
Results
PMMA cartridge had increased β2-m removal rates compared to dialysis filter alone for treatment duration of 240 min. Similarly, the removal rates of α1-m and MMP-3 were higher with PMMA cartridges than with dialysis filter alone. β2-m, α1-m, and MMP-3 clearance improved with the addition of PMMA cartridges, depending on the cartridge size. The removal rates of IL-6 and TNF-α were higher with PMMA cartridges than with dialysis filter alone at 30 min, but not at 240 min .
Conclusion
Direct hemoperfusion with PMMA is an effective method for removing β2-m in hemodialysis patients with DRA. Beneficial effects were also observed for the removal of α1-m and MMP-3. Further research is required to evaluate the long-term efficacy of this approach in managing DRA.