Pro-Con Debate Distributed model of peritoneal transport: implications of the endothelial glycocalyx

osmosis; pathophysiology; peritoneal dialysis Mathematical prediction of clinical events versus physiological research This commentary discusses the conceptual and mathemati-cal modelling of solute and water transport across the peri-toneum and attempts to put a ‘new ’ physiologic entity, the endothelial glycocalyx, into perspective. In the clinic, con-cepts analogous to the membrane barrier in haemodialysis are used to form simplified mathematical schemes to pro-vide rapid estimation of the transport. In contrast, funda-mental research on the pathophysiology of the peritoneal barrier demands models that include important elements of the anatomy that have been demonstrated to influence so-lute and water transport. If potentially critical elements in the barrier, such as the cell-interstitial matrix, are neglected, their importance will never be realized. In this brief article, the potential importance of the endothelial glycocalyx to our understanding of the pathophysiologic changes in the peritoneum is explored. Peritoneal barrier The peritoneal barrier is a complex structure made up of blood vessels surrounded by cells and interstitial matrix, which links the cells within the tissue [1]. Overlying this complicated network is a single layer of mesothelial cells and several layers of connective tissue; together these struc-tures are called the peritoneum, which lines the entire pelvic and abdominal cavities. During peritoneal dialysis (PD), transport occurs between the plasma within the tissue mi-crovasculature and the dialysis solution in contact with peri-toneum of the tissue. The typical solute pathway is across the capillary endothelium through the interstitium and the