Background: While the number of wait-listed patients suffering from kidney failure continues to rise, the number of kidney transplants performed each year has remained stagnant. Development of functional renal tissue using a patient's own cells within a scaffold derived from an unsuitable kidney would alleviate the long-term complications of transplantation, including donor shortage and life-long immunosuppression.

Methods: We decellularized healthy or fibrotic rat kidneys (induced through unilateral ureteral obstruction) to produce normal or fibrotic renal extracellular matrix scaffolds (ECMs). These ECMs were repopulated using human renal proximal tubule epithelial cells (RPTECs) and/or distal tubule-derived renal cortical tubular epithelial cells (RCTECs), and cultured in a bioreactor for 7 days. We evaluated growth and morphology of these cells in mono- or co-culture.

Results: Immunofluorescence showed exclusive expression of N-cadherin by RPTECs, and E-cadherin by RCTECs, respectively, and dual staining was used to distinguish each cell type. In co-culture, heterogenous cell aggregates were observed at day 1, but each cell type gradually self-sorted into distinct regions of the ECM, with RCTECs forming patent tubular structures. The frequency of effective decellularization of abnormal, fibrotic kidney ECMs was decreased compared to normal kidneys. RCTECs proliferated more rapidly within fibrotic ECMs than within normal ECMs, as quantified by resazurin reduction. However, RCTECs did not form polarized tubules with the same consistency, instead forming tubules with multi-layered, non-polarized epithelial cells and cell aggregates lacking lumens.

Conclusion: ECMs derived from healthy or diseased kidneys may be used to investigate specific cell-matrix interactions that influence tubule development, degeneration, or regeneration. The studies will also inform on the use of normal and fibrotic scaffolds as biological templates for generating patient-specific renal tissue for transplantation.

CITATION INFORMATION: Uzarski J, Deaton C, Ward H, Wandinger-Ness A, Miller W, Wertheim J. Mechanisms of Cellular Repopulation within Healthy or Intrinsically Scarred Kidney Extracellular Matrix Scaffolds. Am J Transplant. 2016;16 (suppl 3).

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