Intracorporeal Kidney Support

The feasibility of engineering syngeneic renal tissues in vivo using cloned cells was investigated. The nuclear material from bovine dermal fibroblasts was transferred into unfertilized enucleated donor bovine eggs. Renal cells from the cloned embryos were harvested, expanded in vitro, and seeded onto 3D renal devices. The devices were implanted into the back of the same steer from which the cells were cloned and were retrieved 12 weeks later. The devices revealed formation of organized glomeruli and tubular structures. Immunohistochemical and reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed the expression of renal mRNA and proteins, whereas delayed-type hypersensitivity testing and in vitro proliferative assays showed that there was no rejection response to the cloned cells. RT-PCR performed on the kidney matrices demonstrated the absence of any RNA residues. Renal cells seeded on the matrix adhered to the inner surface and proliferated to confluency 7 days after seeding, as demonstrated by scanning electron microscopy (SEM). Another study demonstrated that parietal epithelial cells (PECs) in the Bowman's capsule exhibit coexpression of the stem cell markers CD24 and CD133 and expression of the stem cell-specific transcription factors Oct-4 and BmI-1. Lineage specific markers are absent in this population.