Controversies in nephrology: Response to ‘renal albumin handling, facts, and artifacts’

• Published in: Kidney international Vol. 72; no. 10; pp. 1195 - 1197
• Main Authors: Russo, L.M., Sandoval, R.M., Brown, D., Molitoris, B.A., Comper, W.D.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.11.2007; Nature Publishing
• Subjects: albumin retrieval; albumin transcytosis; Albumins - metabolism; Albumins - ultrastructure; Albuminuria - metabolism; Albuminuria - physiopathology; Animals; Binding Sites; Biological and medical sciences; Biological Transport; Filtration; glomerular charge; Glomerular Filtration Rate; Kidney - chemistry; Kidney - physiology; Kidney - physiopathology; Kidney Glomerulus - physiology; Kidney Tubules - metabolism; Kidney Tubules - pathology; Kinetics; Low Density Lipoprotein Receptor-Related Protein-2 - metabolism; Medical sciences; Nephrology. Urinary tract diseases; Nephrotic Syndrome - metabolism; Nephrotic Syndrome - pathology; glomerular charge; albumin transcytosis; albumin retrieval; Renal glomerulus; Nephrology; Urinary system; Albumin; Artefact; Transcytosis; Kidney; Urology; Handling
• ISSN: 0085-2538; 1523-1755
• DOI: 10.1038/sj.ki.5002528

For 40 years indirect measurements of the glomerular sieving coefficient of albumin yielded very low values. The first direct measurement by 2-photon microscopy by Russo et al (Kidney Int (2007) 71, 504–513) gives values 50-times higher. This demonstrated that relatively large quantities of albumin are normally filtered based on size selectivity alone. Most of this albumin is retrieved and returned to the blood supply. These new discoveries represent a paradigm shift in our understanding of albumin processing by the kidney. They also serve to explain several anomalous aspects of previous studies on glomerular filtration and mechanism of albuminuria and support the fact that glomerular charge selectivity is not a major factor controlling glomerular permselectivity.