Renal stem cell

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Renal stem cells are special, self-renewing cells in the kidney that can become many different kidney cell types. They help keep the kidney healthy and repair damage, and they may be useful for treating kidney failure in the future.

Where they are and what we know:
- Many studies point to the renal papilla (the tip of the kidney) as a niche for stem cells. A BrdU label-retaining test found a small group of slow-dividing cells there that can rapidly repair damage from temporary blood flow loss. These cells can become other kidney cell types and form spheres in lab cultures, showing they are multipotent.
- Other researchers have suggested stem cells also exist in the renal tubules and in the renal capsule. The capsule contains cells with markers of mesenchymal stem cells, and removing them slows recovery after injury, suggesting they help with repair.

Markers and what they mean:
- Lgr5+ cells have been shown to contribute to parts of the nephron, specifically the ascending limb of the loop of Henle and the distal tubule. This makes Lgr5+ a potential marker for renal stem or progenitor cells.

How repair might happen:
- There is debate about how the kidney repairs itself after injury. Some say stem cells are the main drivers of repair; others say mature kidney cells dedifferentiate (revert to a more primitive state) to act like stem cells. Some findings suggest that damaged tubular epithelial cells proliferate to regenerate tissue.

Examples from studies:
- In mice, multipotent kidney progenitor cells can regenerate multiple cell lineages after injury and improve kidney function and survival.
- It has also been reported that kidney tubular epithelial cells can be reprogrammed back into stem-like cells (iPSCs) using just two factors, Oct4 and Sox2.