Reports of Miniature Livers Harvested
On Sunday, October 31 in Boston, participants of the American Association for the Study of Liver Diseases, were able to review promising reports of lab grown miniature human livers. This, the first step toward man-made livers large enough for transplantation. It is a significant development offering hope to the many people awaiting liver transplants.
These livers were created in a laboratory in North Carolina at Wake Forest University Baptist Medical Center in a study headed by Pedro Baptista, PharmD, Ph.D., and Shay Soker, Ph.D. The ultimate goal of their research is to create personalized livers for transplant by selecting healthy liver cells from a patient and multiplying them to build a new organ.
The Process Scientists Used To Create the Livers
In the lab, the scientists took livers from ferrets and stripped them of their native cells in a process called decellularization. They removed all cells from the structures using a mild detergent, leaving a collagen support structure. They then filled this “scaffold” of the organ with two types of cells: immature human liver cells known as progenitors, and endothelial cells that line blood vessels. The resulting livers were then placed in a bio-reactor which flooded them with nutrients and oxygen, and after a week had passed, the scientists discovered that new, viable liver tissue had grown.
Steps Needed To Test These Livers
Whether these newly made livers can function in a living host is yet to be determined. The challenge of making similar organs large enough for human use lies ahead - the livers created weigh about 0.2 ounces each and are about 1 inch in diameter. A human liver is about 80 times larger. Baptista and Soker’s work will be published in an upcoming issue in the journal - Hepatology.
To ensure the safety of these miniature livers, researchers will attempt to test them on animal models. Experiments like this new one have previously created living livers with animal cells, but this is the first time that scientists have proved they can engineer functional livers with human cells.
Uses of This Research
This news leads many to wonder about the possibilities of creating other lab grown organs using this technique like kidneys and pancreases, of which there is a very low supply. The eventual implications of such research could be astronomical. Instead of waiting for months and years on donor lists, people could have personalized organs produced for them. Bio-engineered livers and other organs would also be valuable as test subjects for evaluating the safety of new drugs without having to endanger the hosts. These bio-engineered organs would more closely correlate to what would happen in a human than the animal models currently used.
Previous Experimentation
Doctors have used techniques similar to these to grow a new trachea for a ten year old boy using his own stem cells and a donated human scaffold. Creating an organ like a windpipe or trachea is (dare I say) relatively simple, requiring only one type of cell to grow in the simple shape of a tube on the scaffold. In a more complicated organ like the liver, scientists have to use multiple types of cells, as described earlier. To date this process has not been attempted with complex organs like the liver, lungs, or heart. Such a process, however, may be realized in just a few short years.
The Limitations of These Experiments
There is a limitation to this work, however. The scaffolds must be created from a donor liver. The blood typing of the individual donor, though, becomes unimportant, as the liver will, through this process, become in effect a universal donor, more or less. The need for anti-rejection medications and worries about rejection become moot in this case. If this process gains enough popularity, scientists will have to look at creating synthetic scaffolds or getting them from other animals. This form of regenerative medicine could theoretically increase the lifespan of humans indefinitely by replacing diseased organs as needed.
Image Sources: Minipic of liver,
Image of Liver in Human Body
