Glomerular filtration: the charge debate charges ahead

The concept that the glomerular filtration barrier exhibits charge selectivity is a basic tenet of renal physiology. Heparan sulfate is a major contributor of glomerular anionic charge. In a new study, prevention of podocytes from synthesizing heparan sulfate, via mutation of Ext1, causes only mild, statistically insignificant albuminuria, despite dramatic alterations in glomerular anionic charge.