Many aspects of the glomerular filtration of macromolecules remain controversial, including the location of the major filtration barrier, the effects of electrical charge, and the reason the filtration barrier does not clog. We examined these issues in anesthetized Necturus maculosus, using fluorescently labeled probes and a two-photon microscope. With the high resolution of this system and the...

Recent studies have emphasized the critical role of podocytes for the size-selective filtration barrier of the kidney and revealed novel aspects of the mechanisms leading to proteinuria, both in inherited and acquired diseases. It has been shown that a specialized cell junction, the slit diaphragm, connecting neighboring podocytes, is of critical importance to the development and the integrity ...

A healthy kidney produces final urine that is practically devoid of proteins and other physiologically important solutes. Tremendous amounts of fluid are filtered every day through the glomerular filtration barrier which is the actual sieving site in the kidney. Failure of the filtering function leads to proteinuria, which is a feature common to nearly all kidney disease. In spite of this pivot...

Glycocalyx, composed of glycoproteins including proteoglycans, coats the luminal surface of the glomerular capillaries. Human heparanase degrades heparan sulphate glycosaminoglycans and is up-regulated in proteinuric states. In this study, we analyze the structure of the human glomerular endothelial cell glycocalyx in vitro and examine its functional relevance, especially after treatment with h...

It is established that the glomerular filter sieves macromolecules based on their size, shape, and charge. Anionic proteins are thus retarded compared with their neutral or cationic counterparts. However, recent studies have indicated that charge effects are small, or even "anomalous," for polysaccharides. We therefore investigated the impact of charge on the glomerular permeability to polysacc...

Kang, Jung Julie, Ildiko Toma, Arnold Sipos, Fiona McCulloch, and Janos Peti-Peterdi. Quantitative imaging of basic functions in renal (patho)physiology. Am J Physiol Renal Physiol 291: F495–F502, 2006. First published April 11, 2006; doi:10.1152/ajprenal.00521.2005.—Multiphoton fluorescence microscopy offers the advantages of deep optical sectioning of living tissue with minimal phototoxicity ...