BACKGROUND: Uraemic toxicity results in the dysfunction of many organ systems, provoking an increase in morbidity and mortality. To date, only approximately 90 uraemic retention solutes have been described. To examine unknown uraemic substances thoroughly, the identification of as many compounds as possible in the ultrafiltrate and/or plasma of patients would lead to a less biased definition of the uraemic retention process compared with what is proposed today. METHODS: We describe the application of a novel proteomic tool for the identification of a large number of molecules present in ultrafiltrate from uraemic and normal plasma obtained with high- or low-flux membranes. Separation by capillary electrophoresis was coupled on-line to a mass spectrometer, yielding identification of polypeptides based on their molecular weight. RESULTS: Between 500 and >1000 polypeptides with a molecular weight ranging from 800 to 10,000 Da could be detected in individual samples, and were identified via their mass and their particular migration time in capillary electrophoresis. In ultrafiltrate from uraemic plasma, 1394 polypeptides were detected in the high-flux vs 1046 in the low-flux samples, while in ultrafiltrate from normal plasma, 544 polypeptides vs 490 were found in ultrafiltrate from normal plasma obtained from membranes with comparable cut-off. In addition, polypeptides >5 kDa were virtually only detected in the uraemic ultrafiltrate from the high-flux membrane (n = 28 vs n = 5 with the low-flux membrane). To demonstrate the feasibility of further characterizing the detected molecules, polypeptides present exclusively in uraemic ultrafiltrate were chosen for sequencing analyses. A 950.6 Da polypeptide was identified as a fragment of the salivary proline-rich protein. A 1291.8 Da fragment was derived from alpha-fibrinogen. CONCLUSION: The data presented here strongly suggest that the application of proteomic approaches such as capillary electrophoresis and mass spectrometry will result in the identification of many more uraemic solutes than those known at present. This could enable the introduction of more direct elimination strategies, since it is possible to obtain an extended appreciation of the removal capacities of particular dialyser membranes.
BACKGROUND: Uraemic toxicity results in the dysfunction of many organ systems, provoking an increase in morbidity and mortality. To date, only approximately 90 uraemic retention solutes have been described. To examine unknown uraemic substances thoroughly, the identification of as many compounds as possible in the ultrafiltrate and/or plasma of patients would lead to a less biased definition of the uraemic retention process compared with what is proposed today. METHODS: We describe the application of a novel proteomic tool for the identification of a large number of molecules present in ultrafiltrate from uraemic and normal plasma obtained with high- or low-flux membranes. Separation by capillary electrophoresis was coupled on-line to a mass spectrometer, yielding identification of polypeptides based on their molecular weight. RESULTS: Between 500 and >1000 polypeptides with a molecular weight ranging from 800 to 10,000 Da could be detected in individual samples, and were identified via their mass and their particular migration time in capillary electrophoresis. In ultrafiltrate from uraemic plasma, 1394 polypeptides were detected in the high-flux vs 1046 in the low-flux samples, while in ultrafiltrate from normal plasma, 544 polypeptides vs 490 were found in ultrafiltrate from normal plasma obtained from membranes with comparable cut-off. In addition, polypeptides >5 kDa were virtually only detected in the uraemic ultrafiltrate from the high-flux membrane (n = 28 vs n = 5 with the low-flux membrane). To demonstrate the feasibility of further characterizing the detected molecules, polypeptides present exclusively in uraemic ultrafiltrate were chosen for sequencing analyses. A 950.6 Da polypeptide was identified as a fragment of the salivary proline-rich protein. A 1291.8 Da fragment was derived from alpha-fibrinogen. CONCLUSION: The data presented here strongly suggest that the application of proteomic approaches such as capillary electrophoresis and mass spectrometry will result in the identification of many more uraemic solutes than those known at present. This could enable the introduction of more direct elimination strategies, since it is possible to obtain an extended appreciation of the removal capacities of particular dialyser membranes.
Authors: Alberto Ortiz; Ziad A Massy; Danilo Fliser; Bengt Lindholm; Andrzej Wiecek; Alberto Martínez-Castelao; Adrian Covic; David Goldsmith; Gültekin Süleymanlar; Gérard M London; Carmine Zoccali Journal: Nat Rev Nephrol Date: 2011-11-01 Impact factor: 28.314
Authors: Dan Theodorescu; Eric Schiffer; Hartwig W Bauer; Friedrich Douwes; Frank Eichhorn; Reinhard Polley; Thomas Schmidt; Wolfgang Schöfer; Petra Zürbig; David M Good; Joshua J Coon; Harald Mischak Journal: Proteomics Clin Appl Date: 2008-03-07 Impact factor: 3.494
Authors: Christos Argyropoulos; Chung-Chou H Chang; Laura Plantinga; Nancy Fink; Neil Powe; Mark Unruh Journal: J Am Soc Nephrol Date: 2009-07-30 Impact factor: 10.121
Authors: Andreas Scherer; Oliver P Günther; Robert F Balshaw; Zsuzsanna Hollander; Janet Wilson-McManus; Raymond Ng; W Robert McMaster; Bruce M McManus; Paul A Keown Journal: BMC Med Genomics Date: 2013-06-28 Impact factor: 3.063
Authors: A Noce; M Ferrannini; R Fabrini; A Bocedi; M Dessì; F Galli; G Federici; R Palumbo; N Di Daniele; G Ricci Journal: Cell Death Dis Date: 2012-08-23 Impact factor: 8.469
Authors: Bruce A Julian; Stefan Wittke; Marion Haubitz; Petra Zürbig; Eric Schiffer; Brendan M McGuire; Robert J Wyatt; Jan Novak Journal: World J Urol Date: 2007-07-10 Impact factor: 3.661