Statement of Benefit to California:
Year 1We have made substantial progress towards increasing our knowledge about early kidney development, identified new ways to differentiate human embryonic stem cells (hESC) to kidney lineages, and explored the use of these and other related kidney cells to study repopulation of the kidney. In order to obtain the necessary cell types for regenerative medicine purposes, differentiation of hESC must follow developmental pathways and recapitulate normal development, and our studies have brought us closer to this goal. Investigations have supported that expression of early developmental markers provides a useful and efficient method to direct differentiation of hESC towards renal lineages. The results of these studies have established cell culture conditions that ensure we can consistently obtain the quantity of differentiated hESC needed for transplantation into developing and damaged kidneys. Significant progress has also been made in developing new and effective techniques for labeling cells for in vivo imaging, and monitoring the labeled cells post-transplantation using positron emission tomography (PET). We have collected sufficient quantities of cells in culture, and identified effective methods to label the cells without altering viability, proliferation, or function. We have also shown that these same cell populations can be used for transplantation into developing kidneys, and that the cells persist post-transplant over time and can be identified using PET. This strategy has allowed us to precisely document cell location post-transplantation in vivo, demonstrated that post-transplant viability was maintained, and shown that the cells did not migrate to other anatomical sites.
Year 2We continue to make substantial progress towards increasing our knowledge about early kidney development and disease, and kidney regeneration strategies, and have successfully applied our methods to differentiate human embryonic stem cells (hESC) to kidney lineages for transplant purposes. We have also accomplished effective radiolabeling of the cells for monitoring post-transplantation, and explored the use of in vivo imaging to monitor the cells.
Year 3These studies focus on kidney development and disease, and new cell-based strategies to regenerate damaged kidneys. We have used human embryonic stem cells (hESC) differentiated towards kidney lineages for transplant purposes and monitored these transplanted cells with positron emission tomography (PET) and other related imaging modalities.
Year 4The U.S. Renal Data System has reported that the rate of pediatric end stage renal disease has tripled since 1980. Congenital anomalies of the kidney are responsible for the majority of chronic renal failure and end stage disease in young children, with congenital obstruction of the urinary tract the most common. These studies are driven by the fact that the clinical condition of congenital urinary tract obstruction is one of the most important problems affecting young children with kidney disease, and with few therapeutic options. In humans, alterations in the events associated with normal kidney development leads to aberrant kidney structure and postnatally to abnormal kidney function. Little is known about the early cell populations of the developing kidney, thus further understanding of developmental processes is essential to guide regenerative approaches that will ultimately be successful. These studies have focused on several key issues such as understanding developmental timelines for key kidney markers, cell populations, and the interactive molecular and cellular milieu during ontogeny; new explant models to aid in developing the techniques necessary to enhance regeneration of kidneys damaged by obstructive renal disease; explant culture conditions using human embryonic stem cells differentiated towards early renal precursors; effective methods for labeling these cells for in vivo imaging in order to monitor engraftment and outcomes post-transplant; and effective methods to transplant renal precursors within a natural framework into defined anatomical locations of the kidney.