Stem-cell therapy for renal diseases.

Significant attention is currently directed to the biological and therapeutic capabilities of stem cells for developing novel treatments for acute and chronic kidney diseases. To date, viable sources of stem cells for renal therapies include adult bone marrow and embryonic tissues, including the metanephric mesenchyme and mesonephros. Native adult kidney stem cells have yet to be identified. Systemically introduced stem cells can engraft in sites of renal disease and injury to show donor phenotypes. Stem cells can differentiate into cells similar to glomeruli, mesangium, and tubules in the kidneys. The impact of stem-cell engraftment and differentiation on renal function presently is unknown. Identification of renal diseases treatable with stem-cell therapies is expected to evolve as stem-cell technologies advance. Methods of modifying stem cells to improve homing, differentiation, and integration into host tissues need further characterization. Ethical and legal controversies about embryonic research and cloning are shaping the regulation and funding of stem-cell research for kidney diseases. Scientific and clinical understanding of stem cells and their potential for renal treatments are in the early stage of development. This field offers great promise, and there are significant opportunities for future investigation in clinical, biological, and ethical aspects of stem-cell therapy for kidney diseases.