* FOR PRESERVATION PURPOSES ONLY * Credit: Tim Sandle

Japanese researchers have successfully grown a pair of kidneys in a laboratory which were transplanted into an animal and verified as functioning correctly. This is the first step to growing such organs and transplanting them into humans.

So far, rats and pigs have been tried. The first wave was with rats, but what is more interesting is the effect with a more complex animal like a pig. The success shown here bring the possibility of a human kidney transplant, using laboratory engineered kidneys, a step closer.

The newly grown kidneys were created from stem cells, using rats as the incubators for the growing embryonic tissue. The kidneys are grown complete with a drainage tube and bladder for the collection of urine.

The biggest problems the researchers faced were removing urine from the kidneys and avoiding them ballooning up under pressure.

Professor Chris Mason, an independent scientist based at University College London, noted:

“This is an interesting step forward. The science looks strong and they have good data in animals.”

Kidneys function to remove excess organic molecules from the blood, and waste products from the metabolism. Kidney transplantation has been in place for decades; however, the process requires a donor kidney which needs to be used within a short time period. Laboratory grown kidneys would, in theory, overcome the common shortfall in which potential recipients often exceed available donor kidneys. Most donated kidneys come from deceased donors, and are the most in-demand organ for transplant, with long waiting lists.

Although the results are very successful, human trials remain a number of years away. A multitude of safety checks is required before a human being goes under surgery for one of the kidneys.

The research was led by Dr Takashi Yokoo of the Jikei University School of Medicine in Tokyo. The research has been published in the journal PNAS. The research paper is titled “Urine excretion strategy for stem cell-generated embryonic kidneys.”