New insights in the molecular mechanisms regulating peritoneal permeability.

Peritoneal dialysis (PD) is used in approximately 15% of dialysis patients worldwide. With the reduction of acute peritonitis, the major problem associated with PD is now the high incidence of ultrafiltration (UF) failure, which can affect up to 50% of PD patients treated for more than 6 years w1x. Cross-sectional and longitudinal studies have shown that peritoneal permeability for small solutes increases with time on PD, which induces a faster absorption of glucose, an early dissipation of the osmotic gradient and, eventually, UF failure w1,2x. The relevance of these modifications is illustrated by the fact that high peritoneal membrane (PM) permeability is a significant risk factor, predicting both technical failure and death in PD patients w3x. In this commentary, we will discuss how recent structural, functional and molecular data provide new insights in our understanding of the modifications of the PM in long-term PD.