Substrate Elasticity Governs Differentiation of Renal Tubule Cells in Prolonged Culture

End-stage renal disease afflicts nearly 750,000 Americans and claims over 100,000 lives annually in the United States. Kidney transplantation is associated with longest survival and least cost but is limited by scarcity of donor organs. Most patients are treated with hemodialysis. Each hemodialysis treatment consumes over 160 liters of water and anchors the patient to a machine for 12-15 hours per week. Cultured tubule cells can reduce the obligate fluid requirements of a bioengineered artificial kidney by concentrating wastes and reabsorbing filtered salt and water. Primary tubule epithelial cells rapidly dedifferentiate in culture and form a flattened epithelium lacking the brush border essential to apicobasal transport. We hypothesized that substrate mechanical properties t have a strong influence on differentiation in primary cell culture. We cultured primary renal tubule cells on polyacrylamide hydrogels of varying elasticity and measured expression of key transporter proteins essential to renal tubu...