Volume 84, Issue 5, Pages 861-863 (November 2013) The role of the kidney in protein metabolism: the capacity of tubular lysosomal proteolysis in nephrotic syndrome  Akihiro Tojo  Kidney International  Volume 84, Issue 5, Pages 861-863 (November 2013) DOI: 10.1038/ki.2013.284 Copyright © 2013 International Society of Nephrology Terms and Conditions

Figure 1 Glomerular filtration and tubular reabsorption of albumin, low-molecular-weight proteins (LMWPs), and high-molecular-weight proteins (HMWPs) in normal controls and subjects with focal segmental glomerulosclerosis. In normal controls, the values are calculated based on the fractional micropuncture data obtained in normal rats (Tojo A & Endou H, Am J Physiol 263:F601, 1992) and adapted to humans with a glomerular filtration rate (GFR) of 100ml/min. In subjects with focal segmental glomerulosclerosis, the albumin concentration in Bowman’s capsule is calculated using the sieving coefficient of 0.025,6 and reduced plasma albumin in nephrotic syndrome. In subjects with nephrotic syndrome, tubular reabsorption of proteins is increased up to 13 times and lysosomal proteolysis enzymes are enhanced up to 8 times that observed in controls.4 However, the capacity for tubular reabsorption of albumin is approximately 30g per day; therefore, the remaining glomerular filtrated albumin is excreted in the urine. Tubules overloaded with proteins produce pro-inflammatory cytokines, causing tubulointerstitial damage. The small red dots represent LMWPs, the green ellipsoids represent albumin, and the large purple ellipsoids represent HMWPs. Kidney International 2013 84, 861-863DOI: (10.1038/ki.2013.284) Copyright © 2013 International Society of Nephrology Terms and Conditions