In the live thesis building blogxperiment I edit (digest, compile, write, rewrite, delete) my ongoing doctoral thesis in blog posts and put the parts together on thesis live. The title: The physiologic role of stem cells in tissues with different regenerative potential.
1.2. Tissues, organs with different turnover and regenerative potential
In the adult kidney the nephrons (approximately 500 000 nephronic units/kidney) develop from the metanephric mesoderm/mesenchyme while the collecting ducts are coming from the ureteric bud. The kidney is a complex structure with at least 26 different cell types. The renal function is particularly age-dependent (loss of functional renal mass up to 25%). The kidney is an active tissue with high energy demand and contains a lot of mitochondria (especially in the proximal tubules). On the other hand, while the turnover rate is low, there is a robust although limited regenerative response to acute kidney injury. The candidate cellular sources of recovery, replacement: adjacent, less damaged tubular cells, resident adult kidney stem/progenitor cells and circulating mesenchymal cells from the bone marrow. Amongst others the following cell surface markers were used for isolating/enriching stem cell/multipotent renal progenitor populations: CD133, stem cell antigen-1 (Sca-1), CD24, CD90, Pax-2, Oct-4, Rex-1 (see table).
One such population was isolated from the cortical interstitium making up 0.8% of all cortical cells and were capable to differentiate into epithelial and endothelial like cells in vitro forming tubular structures in SCID mice [Bussolati et al, 2005]. In the lack of definitive markers of kidney stem cells not much certain could be said on the kidney stem cell niche.
Literature: Gupta S, Rosenberg ME. (2008) Do Stem Cells Exist in the Adult Kidney? Am J Nephrol. 19;28(4):607-613
Percy CJ, Power D, Gobe GC. Renal ageing: changes in the cellular mechanism of energy metabolism and oxidant handling. Nephrology (Carlton). 2008 Apr;13(2):147-52.
Bussolati B, Bruno S, Grange C, Buttiglieri S, Deregibus MC, Cantino D, Camussi G. (2005) Isolation of renal progenitor cells from adult human kidney. Am J Pathol. 2005 Feb;166(2):545-55.
