Study of Biocompatibility of Membranes in Online Hemodiafiltration

The biocompatibility of dialysis membranes is a determining factor in avoiding chronic microinflammation in patients under haemodialysis. Lower biocompatibility has been related to increased inflammatory status, which is known to be associated with cardiovascular events. Classically, cellulose membranes have been considered bioincompatible. A new-generation of asymmetric cellulose triacetate (CTA) membranes allows the performance of high convective transport techniques, but there have been no studies of their biocompatibility. The aim of the present study was to analyze and compare the biocompatibility characteristics of 4 membranes, including CTA, in online hemodiafiltration (OL-HDF) patients.

We included 15 patients in -OL-HDF. After a 2-week washout period with helixone membrane, each patient was treated with the 4 membranes (polyamide, polynephron, helixone and CTA) for 4 weeks in a randomized order. The other dialysis parameters were kept stable throughout the study. We studied changes in markers of the activation of the complement system, monocytes, platelets, and adhesion molecules with the 4 membranes, as well as inflammatory parameters.

Biocompatibility was similar among the membranes. There were no sustained differences in complement activation, measured by C3a and C5a levels, or in platelet activation, determined by levels of P-selectin and platelet-derived microparticles (CD41a+). No differences were observed in activated monocyte levels (CD14+/CD16+) or in plasma levels of interleukin (IL)-1, IL-6, IL-10 or high-sensitivity C-reactive protein, although tumour necrosis factor-α levels decreased when the patients were dialyzed with CTA. No significant differences were found in markers of endothelial damage, assessed by levels of plasminogen activator inhibitor-1 and adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1).

The 4 membranes evaluated in this study in stable patients on OL-HDF, including the new-generation CTA, show similar biocompatibility with the methods applied.