Development of an In-Vitro Glomerulus

Our lab previously characterized the use of a multi-channel microfluidic glomerular device containing both biological (Human Umbilical Vein Endothelial Cells (HUVECs)) and artificial physical (8nm polyethersulferone (PES) membranes) mechanisms of filtration. This model was found to filter 71% BSA-FITC in solution. However, in-vivo, cells are responsible for filtration through vein endothelial cells and podocytes, cells fundamental to filtration due to slit diaphragms, within the glomerulus. Our current focus is on improving this glomerular device by the addition of conditionally immortalized human podocyte cells (CIHP-1) and use of larger pore size membranes incapable of filtering to create a more realistic model. Before doing so, membranes were exposed to flow and found to maintain shape, cells were identified by light microscopy and immunohistochemistry, and coatings were optimized to keep cells on membranes during flow. Podocytes’ slit diaphragms allow them to filter small to large molecules ranging from 3 kDa to around 150 kDa. Previous work found 30nm polyethersulferone membranes seeded with HUVECs unable to filter BSA-FITC, a medium sized molecule at 65 kDa. With the inclusion of podocytes, a 70% filtration of BSA conjugated with AlexaFluor 488 was achieved. However, the small molecule Ovalbumin conjugated with AlexaFluor 488 (45 kDa) and the larger molecule Rabbit IgG-FITC (160 kDa) were not filtered. While the model has regions to improve itself, it certainly contains prospects for providing better analysis of disease progression, reduction in nephrotoxicity of drugs, and improved treatment for renal diseases