Carmine Zoccali

Iron is the metal of Mars, the warrior god. This week Dr Barasch, Columbia University, recapitulates the story of a novel, truly fascinating iron-carrying protein, neutrophil gelatinase-associated lipocalin (NGAL). This protein is fundamental  to ensure iron trafficking in the kidney. The major form of iron in circulation is ferric iron which is completely insoluble at neutral pH. The movement of ferric iron from site to site requires carriers the most well known being transferrin. NGAL is a lipocalin, a class of about 50 binding proteins including also retinol binding protein. NGAL appears in the urine within hours of an ischemic event and the appearance of NGAL in the urine precedes more common markers and for this reason it is intensively investigated as an early marker of renal  damage in various situations from cisplatin toxicity to cardiac surgery and renal transplantation (see also the recent NDTe lecture by Dr Rondeau at http://www.ndt-educational.org/rondeauslide2006txt.asp). Unlike the urinary form of NGAL, circulating NGAL does not appear in the urine because it is completely taken up by the proximal tubule via a megalin receptor. The site of production of NGAL in the kidney is insult-dependent. Thus, in ischemia NGAL is made up mainly by the thick ascending limb but also by the collecting duct  in urinary obstruction. NGAL is an important siderophore and full understanding of the involvement of this protein in the iron-cycle  will advance our knowledge of iron physiology and pathophysiology. The second lecture of this week, by Dr Eckardt, University of Erlangen/Nuremberg Germany, focuses on feedback control of erythropoietin production and regulation of red cell production. Dr Eckardt nicely broadens the problem putting it in a more general context where erythropoietin is just an element of a system aimed at  maintaining  adequate oxygenation at organ level. Hypoxia inducible genes, and the HIF family of transcription factors play a major role in this system and the contribution of erythropoietin to this system goes beyond red cells production and extends to organ protection.

We have sufficient numbers (over 900 participants) to read the poll on how European nephrologists refresh or acquire knowledge related with presentations at medical congresses. Here we have a surprise. Till a few years ago CDs and DVDs were the most popular medium used by doctors and we expected that these media would have had a preponderant share also in our poll. In contrast, powerpoint lectures directly consulted and/or downloaded from the  Internet (43%) and Internet available of Congresses highlights (24%) largely dominated the scene. The share of CDs and DVDs is quite minuscule (14%) and inferior also to that of audiofiles (19%). This poll of ours is in line with a recent Newsweek article sanctioning the death of CDs and DVDs. Perhaps the money invested on these media now needs to be diverted to the cyberspace..

Enjoy your NDTe

Carmine Zoccali – Editor in Chief NDT-Educational