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

MC3 Develops Promising Artificial Lung

Patients suffering from acute respiratory failure or other lung associated complications have few treatment options. Although respiratory assist devices do exists, most require intubulation that leads to infection, are costly, and the devices are immobile. For these reasons, the medical community is in search for an artificial lung. MC3, a medical device company is creating such a lung.

MC3 Biomedical Engineer Scott Merz of Ann Harbor, Michigan has a 5$ million grant from the National Institute of Health to develop such an artificial lung. Currently Merz has developed a soda-canned sized artificial lung containing bundles of polymer fibers that function to exchange carbon dioxide and oxygen as blood washes over them. The BioLung is worn outside the body and attached to larger blood vessels in the chest, arms, or legs. Similar to natural lungs, the Biolung relies on the heart to pump blood through, and this allows the blood to flow naturally between the high pressure in an artery to the lower pressure in a vein. Similar companies testing comparative devices have seen success with temporary use.

Merz states the largest obstacles are finding a membrane that allows oxygen-carbon dioxide exchange without causing blood to clot or damaging the blood. Some research exists in discovering enzymes that, when coating the fibers of the artificial lung, accelerate the removal of carbon dioxide from the blood. However, most lung-assist devices, and potential lung implants are currently for temporary use.


http://www.usatoday.com/news/health/2008-01-29-artificial-lungs_N.htm