Pee-brain: cells in urine converted to neurons

Scientists have converted kidney cells from human urine into brain cells, bypassing the need for embryonic stem cells. Converting mature cells from one type to another through the creation of induced pluripotent stem cells (iPS cells) has been done before, however the current study makes two notable changes to improve the speed and safety of the procedure.

Firstly, previous studies have collected cells for this procedure via a blood or skin sample. The use of kidney cells isolated from a urine sample is a less invasive method.

'We work on childhood disorders and it's easier to get a child to give a urine sample than to prick them for blood', said medical geneticist Dr James Ellis from the University of Toronto, who was not involved in the study, to Nature News.

Secondly, the production of iPS cells usually involves infecting the skin or blood cells with a virus containing the genes required for reprogramming the cells to an immature state. The viral DNA becomes incorporated into the cells own genome, causing it to potentially become more unstable and prone to developing harmful mutations that could result in tumours.

Researchers led by Professor Duanqing Pei at the Guangzhou Institute of Biomedicine and Health in China, instead chose to infect the kidney cells with a circular piece of DNA from bacteria. This DNA carried the genes required to reprogramme the cell, but did not become incorporated into the cells own genome.

The technique was faster and may avoid the problems of tumour development, although the group has yet to show if this is the case long-term. 'This could definitely speed things up', remarked Dr Ellis.

Infecting the kidney cells with the bacterial DNA, transformed them into an immature form of brain cells called neural progenitors. These progenitors were able to develop into mature brain cells; both neurons and glia. The cells were then transplanted into rat brains and a month later were still alive and had not formed tumours.

This non-invasive technique could make it easier to generate brain cells from a patient, which scientists could study to better understand neurodegenerative diseases and potentially test new treatments on.