Uremic toxicity: present state of the art

The uremic syndrome is a complex mixture of organ dysfunctions, which is attributed to the retention of a myriad of compounds that under normal condition are excreted by the healthy kidneys (uremic toxins). In the area of identification and characterization of uremic toxins and in the knowledge of their pathophysiologic importance, major steps forward have been made during recent years. The present article is a review of several of these steps, especially in the area of information about the compounds that could play a role in the development of cardiovascular complications. It is written by those members of the Uremic Toxins Group, which has been created by the European Society for Artificial Organs (ESAO). Each of the 16 authors has written a state of the art in his/her major area of interest.     

Effects of Blood-Dialyser Interaction on Prostaglandins in Uraemic Patients and in Healthy Man

The present study examines extracorporeal prostaglandin productionduring routine and simulated haemodialysis in healthy volunteers.The roles of dialyser membranes and alcohol washing procedureswere investigated. The source of extracorporeal prostaglandinE₂ was estimated by a specific platelet cyclo-oxygenase antagonist.Extracorporeal thromboxane production, with and without antagonist,was compared in an attempt to substantiate the role of the cyclo-oxygenasepathway by sources other than platelets. Clinical investigationsshow that prostaglandin liberation in the extracorporeal bloodstreamis detectable. Additionally, laboratory results suggest an associationbetween the type of dialyser membrane and extracorporeal prostaglandinrelease. The amount of prostaglandin E₂ was reduced when dialyserswere pre-washed with alcohol. Furthermore, it was experimentallypossible to determine that a large part of extracorporeal prostaglandinE₂ is released by sources other than platelets, suggesting apossible role of monocytes in extracorporeal prostaglandin production.     

New insights into the biology of peritoneal mesothelial cells: the roles of epithelial-to-mesenchymal transition and cellular senescence

Ultrafiltration failure due to dysfunction of the peritoneum as a dialyzing organ is a major clinical limitation of peritoneal dialysis. It is increasingly clear that mesothelial cells play an important role in fibrogenesis and vasculopathy that underlie peritoneal membrane dysfunction. New and extensively studied aspects of peritoneal mesothelial cell biology include epithelial-to-mesenchymal transition and cellular senescence. We discuss the potential significance of these processes for the peritoneal membrane function.