Okayama City, Japan (PRWEB UK) 2 December 2014

Researchers at Okayama University Graduate School of Medicine and Kyorin University School of Medicine have successfully generated a kidney-like structure from just a single cell.

It has been predicted that the kidney will be among the last organs successfully regenerated in vitro due to its complex structure and multiple functions, states Shinji Kitamura, Hiroyuki Sakurai and Hirofumi Makino at the beginning of their latest report, before continuing to describe results suggesting a far more positive prognosis for the pace of kidney regeneration research. Despite the anatomical challenges posed by the kidney anatomy and the complexities understood from embryonic kidney development processes, the researchers have demonstrated that kidney-like structures can be generated from just a single adult kidney stem cell.

In embryos, kidney development requires two types of primordial cells cells at the earliest stage of development. However by generating kidney-like structures from a single type of kidney stem cell the researchers provide evidence for differences in the organ development in adults and embryos.

Kitamura, Sakurai and Makino researchers from Okayama and Kyorin Universities - took kidney stem cells from the different kidney components of microdissected adult rats and grew them in culture. A method for growing three-dimensional cell clusters showed that kidney-like structures could form so long as the initial cell cluster was large enough.

The minimum cluster size required might suggest that not all the kidney stem cells have stem cell characteristics. Therefore the researchers cloned kidney stem cells and confirmed that kidney-like structures still formed from the clusters of clone cells after a few weeks.

The researchers add, Although the physiological roles of such cells are currently unclear, analogous cells in the adult human kidney would be a valuable resource for the regeneration of kidneys in vitro.

Background Kidney structure There are more than a dozen distinct types of cell in the kidneys. The basic structural unit of the kidney is the nephron, which filters the blood to regulate the concentration of water and soluble substances such as sodium salts. Each nephron comprises several well-defined segments: the glomerulus, the proximal tubule, the loop of Henle, the distal tube and the collecting duct.

In embryo kidney organogenesis two primordial cell types are required to differentiate into all the different cell types in the kidney: metanephric mesenchymal cells and uteric bud cells. Kitamura, Sakurai and Makino produced kidney cells that could differentiate into a kidney-like structure without these primordial cell types, suggesting these are adult kidney stem cells.

Obtaining kidney stem cells The researchers microdissected adult rat kidneys into segments from the glomeruli, proximal convoluted tubule (S1/PCT), proximal straight tubule (S2, S3), medullary thick ascending limb of Henles loop and the collecting duct. They then grew the cells on mouse mesenchymal cells. While there is no known single biomarker for adult kidney stem cells, immunohistochemical anaylysis identified a number of markers in the kidney stem cells- that are found in embryonic or adult kidneys.

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Kidney organ regeneration research leaps forward