Antioxidant assessment of vitamin E-coated hemodialysis membranes: mechanistic context and implications for novelty

Abstract

Abstract Vitamin E-coated polysulfone (VE-PS) dialysis membranes were developed to enhance both antioxidant performance and biocompatibility of conventional dialyzers and have been investigated for more than three decades both in experimental models and clinical studies. Tange et al. recently reported that VE-PS membranes retain greater antioxidant capacity than conventional polysulfone following exposure to Fenton’s reagent and proposed their assay as a new standardized in vitro method. Although the experimental approach differs from previous protocols, the article overlooks key earlier studies that had already established the antioxidant properties of VE-PS membranes. Prior investigations conclusively demonstrated the electron-donating (reducing) capacity of membrane-bound α-tocopherol, quantified the antioxidant capacity of VE-PS membranes, and characterized electron transfer to the Fe3⁺/Fe2⁺ redox couple that underlies Fenton chemistry. These studies therefore addressed the same biological property and the same mechanistic framework examined by Tange et al. Failure to consider this evidence substantially affects the assessment of the study’s originality and limits the interpretation of its methodological contribution. The new assay represents an alternative oxidative challenge and analytical readout rather than the first demonstration or first quantitative evaluation of VE-PS membrane antioxidant activity. Its added value should therefore be interpreted as incremental and benchmarked against previously validated methodologies instead of being presented as establishing a previously uncharacterized property.