To answer this question, we retrospectively studied USP of patients treated with either high-flux (HF) or medium-cut-off (MCO) dialyzers (7, 41), observing significant improvements in the expression of KLF2 in the MCO group, which is in line with improvements in other inflammatory pathways and reduced endothelial maladaptation (7). This evidence concerns the gene KLF2 and hydrops fetalis.