Abstract
Chronic kidney disease (CKD) is progressively loss of renal filtration function. Here we report an in vitro model of podocyte culture that reconstitutes glomerulus filtration function and pathological behavior in response to hypertension, which is one of the leading causes of CKD. Podocytes, the glomerular epithelial cells that processes highly branched architecture essential for glomerular filtration, has been the central focus for studying CKD. Mimicking the glomerular basement membrane, podocytes grew on collagen coated anodic aluminum oxide (AAO) membranes exhibited high degree of cell spreading and fastest growth rate. To study the influence of hypertension, confluent podocytes on porous membrane was sandwiched by upper and lower chambers supplying with transmembrane pressure ΔP. The filtration function was validated using dextran. The result shows dextran in 20 kDa and 70 kDa can penetrate the podocyte membrane whereas dextran in 500 kDa was blocked until ΔP > 60 mmHg, which resembles the level of hypertension. Additionally, with the increase of ΔP, we found that more foot processes grew and reached a maximum at ΔP = 30 mmHg (19.718%) but it decays when ΔP is further increased. Moreover, analysis of mRNA expression shows synaptopodin is also down-regulated when ΔP > 40 mmHg. These results suggest that the dysfunction of renal filtration is correlated with the reduction of foot processes and synaptopodin expression but not just cytoskeletal reorganization. Taking together, our in vitro platform enables the reconstitution of renal function and investigation of CKD mechanism, with implications for drug development in the future.