PURPOSE OF REVIEW: Each day, the human kidneys filter about 140 l of primary urine from plasma. Although this ultrafiltrate is virtually free of plasma protein, the glomerular filter never clogs under physiological conditions. Upto today it is still not entirely resolved as to how the kidney accomplishes this extraordinary task. Most of the proposed models for glomerular filtration have not considered electrical effects. RECENT FINDINGS: In micropuncture studies, we have directly measured an electrical field across the glomerular filtration barrier. This potential difference is most likely generated by forced passage of the ionic solution of the plasma across the charged glomerular filter ('electrokinetic potential'). As all plasma proteins are negatively charged, the electrical field across the glomerular filtration barrier is predicted to drive plasma proteins from the filter toward the capillary lumen by electrophoresis. SUMMARY: In this review, we examine our novel model for glomerular filtration in more detail. We outline the physical mechanisms by which electrokinetic effects (streaming potentials) are generated. We investigate the potential impact of the electrical field on the passage of albumin across the glomerular filtration barrier. We review the mathematical heteroporous model including electrical effects and analyse a selection of experimental studies for indications that electrical effects influence glomerular permeability significantly.
PURPOSE OF REVIEW: Each day, the human kidneys filter about 140 l of primary urine from plasma. Although this ultrafiltrate is virtually free of plasma protein, the glomerular filter never clogs under physiological conditions. Upto today it is still not entirely resolved as to how the kidney accomplishes this extraordinary task. Most of the proposed models for glomerular filtration have not considered electrical effects. RECENT FINDINGS: In micropuncture studies, we have directly measured an electrical field across the glomerular filtration barrier. This potential difference is most likely generated by forced passage of the ionic solution of the plasma across the charged glomerular filter ('electrokinetic potential'). As all plasma proteins are negatively charged, the electrical field across the glomerular filtration barrier is predicted to drive plasma proteins from the filter toward the capillary lumen by electrophoresis. SUMMARY: In this review, we examine our novel model for glomerular filtration in more detail. We outline the physical mechanisms by which electrokinetic effects (streaming potentials) are generated. We investigate the potential impact of the electrical field on the passage of albumin across the glomerular filtration barrier. We review the mathematical heteroporous model including electrical effects and analyse a selection of experimental studies for indications that electrical effects influence glomerular permeability significantly.
Authors: Verena Tenten; Sylvia Menzel; Uta Kunter; Eva-Maria Sicking; Claudia R C van Roeyen; Silja K Sanden; Michaela Kaldenbach; Peter Boor; Astrid Fuss; Sandra Uhlig; Regina Lanzmich; Brigith Willemsen; Henry Dijkman; Martin Grepl; Klemens Wild; Wilhelm Kriz; Bart Smeets; Jürgen Floege; Marcus J Moeller Journal: J Am Soc Nephrol Date: 2013-08-22 Impact factor: 10.121
Authors: Christoph Kuppe; Wilko Rohlfs; Martin Grepl; Kevin Schulte; Delma Veron; Marlies Elger; Silja Kerstin Sanden; Turgay Saritas; Johanna Andrae; Christer Betsholtz; Christian Trautwein; Ralf Hausmann; Susan Quaggin; Sebastian Bachmann; Wilhelm Kriz; Alda Tufro; Jürgen Floege; Marcus J Moeller Journal: Nephrol Dial Transplant Date: 2018-09-01 Impact factor: 5.992
Authors: Franziska Lausecker; Xuefei Tian; Kazunori Inoue; Zhen Wang; Christopher E Pedigo; Hossam Hassan; Chang Liu; Margaret Zimmer; Stephanie Jinno; Abby L Huckle; Hellyeh Hamidi; Robert S Ross; Roy Zent; Christoph Ballestrem; Rachel Lennon; Shuta Ishibe Journal: Kidney Int Date: 2017-12-12 Impact factor: 10.612