In what is thought to be a first, stem cells have been used to generate human kidney tissue.
Experiments led by Dr Kenji Osafune at Kyoto University in Japan, used human induced pluripotent stem cells, which can be programmed to become any of the cells in the body. The scientists first grew a kind of tissue called intermediate mesoderm - a middle point between the stem cells and specialised kidney tissue.
'There are about 200 types of cells in the human body, but this tissue grows into only three types of cells', Dr Osafune told AFP. As well as kidney cells, intermediate mesoderm tissue can develop into adrenal cells or reproductive gland cells.
From the intermediate mesoderm, the scientists were able to generate part of the urinary tubule, which is important in the production of urine.
The study is significant because it points towards future clinical applications. Kidney tissue cannot regenerate or repair itself and currently patients with damaged or diseased kidneys rely on time-consuming dialysis until they are matched with an organ donor.
Kidney transplantation is far from risk-free and donor shortages are widespread. Even successful transplant patients require another transplant after 10-15 years.
Dr Osafune stressed that the study, published in Nature Communications, is only a small step towards kidney tissue grown from stem cells being used clinically. 'It is not known yet if simply transplanting regenerated cells would really cure kidney ailments', he said.
Dr Takahashi Yokoo, of Jikei University, Tokyo, who was not involved with the study, agreed, telling AFP: 'Yes, a tubule structure was generated, but an enormous amount of research is still necessary to create an orderly structure that produces urine'.
Nonetheless, Dr Osafune said that his team had taken 'the preliminary step on the road to the clinical level'.