INTRODUCTION AND OBJECTIVES: End stage renal disease is currently being treated effectively by transplantation. However, increasing demand and donor shortage make this treatment challenging. Recent advances in cell-based therapies have provided potential opportunities to alleviate the current challenges of donor shortage. We previously have demonstrated that single renal cells expanded in culture are able to form renal structures when implanted in vivo. However, the levels of structure formation could not be adequately controlled. In this study, we investigated whether human kidney structures could be pre-formed in vitro for subsequent implantation in vivo to maximize tissue forming efficiency

METHODS: Primary human renal cells were isolated from unused donor kidneys using enzymatic digestion methods. Renal cells were grown, expanded and characterized using cell specific antibodies. To form kidney structures, single renal cells were placed in a three-dimensional culture system, consisting of neutralized type I collagen. The three-dimensional matrix with cells was solidified and cultivated over a period of 10 days. Histomorphological and ultrastructural analyses were performed using cell specific markers that identify proximal and distal tubules and collecting ducts.

RESULTS: Human primary renal cells were effectively isolated and expanded in culture. The cells retained their phenotypic and functional characteristics at multiple culture stages. Single renal cells placed in a three-dimensional culture environment began to proliferate and form structures that resemble renal tubules. Histologically, these structures showed phenotypic resemblance to native kidney structures. The reconstituted tubules stained positively for proximal and distal tubular markers. E-cadherin and N-cadherin staining confirmed polarization of the cells present in the tubules

CONCLUSIONS: These findings show that single human renal cells grown in a three-dimensional culture system are able to generate kidney structures. The cells constituting these structures maintained the expression of renal cell specific markers. This system may ultimately be developed into an efficient cell-based therapy for patients with end stage renal disease

Source of Funding: This study was supported by Tengion, Inc. through a sponsored research agreement.