Miracle Grow

Above: Synthetic scaffold of an ear (photo credit: Rebecca Hale, NGM Staff)

Bioartificial organs, or organs grown from a patient's own cells, are seeing advances in an effort to overcome the problems of transplant rejection and the shortage of organs. Recently, Anthony Atala worked with a team of researchers at the Wake Forest Institute for Regenerative Medicine have developed a technique for a lab-grown bladder. A balloon-shaped scaffold is created from collagen and seeded with healthy bladder cells from a patient's diseased bladder, then incubated at body temperature for six to eight weeks. At least two different types of cells are used: urothelial and muscle. They are seeded in the appropriate locations, urothelial on the inside and muscle on the outside. At least 30 people to date have received lab-grown bladders.

This technique, however, has limitations: the bladder's vasculature is far less extensive than that of solid organs such as kidneys or livers. Angiogenesis is a complex process, and the direction of growth is less predictable than layers of cells surrounding hollow organs. Despite this hurdle, Atala's team produced a piece of liver using a technique analogous to a jet printer, which "prints" a layer of cells on the scaffold one at a time.

Additionally, using a patient's cells may not be an option if the organ is too diseased, as may be the case with advanced cancers. The usage of embryonic stem cells has long been a controversy, primarily because the embryo is damaged or destroyed in the process - but Atala's team has proven a way that leaves the embryo unharmed by using amniotic fluid in the womb. They subsequently have grown a variety of cell types, although not necessarily complete organs. In a bank of stem cell types, it could be possible to have a "library" from which to order organs from in the future.

Other bioartificial organs of notable mention in this article include a jawbone at Columbia University, a lung at Yale, and a non-implantable kidney at the University of Michigan.

After the SNBAL on a regenerated lung, I was curious about the progress of other bioartificial organs. Apparently, the idea of using a decellurized bioscaffold is not exactly new, with Taylor's heart being grown on its scaffold in 2008. Additionally, I found the author's view on embryonic stem cell usage to be thought-provoking: if we aren't harming the embryo while extracting the cells, will the number of ethical objections be just as high? I could see a potential "God-complex" argument. Finally, growing organs has been of interest to me since I discovered the field of biomedical engineering, and it's interesting to know that so many successful techniques are based off of using bioscaffolds. Perhaps I should consider a different track if the idea of working with stem cells is unappealing.

National Geographic, March 2011
"Miracle Grow", Josie Glausiusz
http://ngm.nationalgeographic.com/2011/03/big-idea/organ-regeneration-text