Every year, at least 1,500 people die on the waiting list for a new liver because of a donor shortage.
It would be convenient to just press the "new liver" button on a 3-D printer and watch the organ take shape on a plate. Unfortunately, that technology does not yet exist. But an Eden Prairie company called Miromatrix is taking a different approach, working from the premise that humans don't have to invent a new way to grow organs — nature does that just fine, thanks. The trick, rather, is in taking a liver from one body and implanting it inside another without triggering rejection.
Scientists at Miromatrix think they may have the answer. It involves taking the liver from a pig that was slaughtered for food, washing away the living cells in a mild detergent, and then "reseeding" the resulting white collagen shell with human cells that can transform the pig liver into a functioning human organ.
It may sound like science fiction, but the first attempt at this will take place before the year is out: A pig at the Mayo Clinic will have its liver removed, and a new liver "recellularized" with human and pig cells implanted in its place, to test whether a Miromatrix bioengineered liver can keep the pig alive for at least two days. Results of the experiment should be in by this time next year, and that may clear the way for the first human implant around 2020.
"This has really been the promise of regenerative medicine: How do you create products that can cure disease?" said Jeff Ross, a longtime biomedical researcher who became CEO of Miromatrix during a shake-up at the company earlier this year. "This would be the first product of its kind."
Although other companies and academic labs have figured out how to strip away living cells from an organic structure to leave behind only the "decellularized" matrix, Miromatrix relies on a patented process invented at the University of Minnesota called "perfusion decellularization."
Typically, decellularization is accomplished by soaking the organ in a special solution, but Ross says this method of "immersion perfusion" penetrates only a few millimeters into tissue. That's why other decellularized tissue matrices on the market tend to be thin, like skin-matrix products.
Perfusion decellularization, in contrast, involves mechanically pumping a cleaning solution through an organ's natural internal vasculature continuously for a day or two, until all that's left is the inert white "matrix" of collagen and other proteins that can be preserved in a refrigerator for months at a time. Critically, the resulting matrix still retains tiny tunnels from the original blood vessels, allowing new cells to grow their own vascular system inside the existing structure.
