Lab-Engineered Kidney Project Reaches Early Milestone

Photo: Kidney

In proof-of-concept research the team successfully used pig kidneys to make “scaffolds” or support structures that could potentially one day be used to build new kidneys for human patients. The idea is to remove all animal cells – leaving only the organ structure or “skeleton.” A patient’s own cells would then be placed on the scaffold, making an organ that the patient theoretically would not reject.

While this is one of the first studies to assess the possibility of using whole pig kidneys to engineer replacement organs, the idea of using organ structures from pigs to help human patients is not new. Pig heart valves – removed of cells – have been used for more than three decades to provide heart valve replacements in human patients.

“It is important to identify new sources of transplantable organs because of the critical shortage of donor organs,” said lead author Doctor Giuseppe Orlando, an instructor in surgery and regenerative medicine at Wake Forest Baptist. “These kidneys maintain their innate three-dimensional architecture, as well as their vascular system, and may represent the ideal platform for kidney engineering.”

For the research, pig kidneys were soaked in a detergent to remove all cells, leaving behind the organ’s “skeleton,” including its system of blood vessels. In addition, the structure of the nephron – the kidney’s functional unit – was maintained. The scaffolds were implanted in animals, where they were re-filled with blood and were able to maintain normal blood pressure, proving that the process of removing cells does not affect the mechanical strength of the vessels.

“There are many challenges to be met before this system could be used to engineer replacement kidneys, including problems with blood clots forming in the vessels,” said Doctor Anthony Atala, co-author and director of the Wake Forest Institute for Regenerative Medicine. “The kidney is a very complex organ with at least 22 different cell types.”

But, the fact that nephron structure is maintained suggests the potential to re-populate the kidney with cells, according to the scientists. They speculate that new cells introduced into the scaffold would recognize their natural niche through physical or chemical signals of the scaffold.

While the project is in its infancy, the idea represents a potential solution to the extreme shortage of donor kidneys. According to the authors, the probability in the U.S. of receiving a kidney transplant within five years of being added to the waiting list is less than 35 percent. As of late August 2011, nearly 90,000 patients in the U.S. were waiting for kidney transplants.; Source: Wake Forest Baptist Medical Center