Some of the chemical factories and filters in our bodies could be replaced by any device that performs the same function, and that device doesn't have to look anything like the structures they replace. However, the easiest way to recapitulate the original tissue function is still to use actual tissue, either donor or engineered. Researchers here report that decellularization, removing the cells from donor tissue and replacing them with the recipient's cells, is potentially a way to use discarded donor tissue as the basis for bioartificial organs:
The pancreas is a large gland near the stomach that secretes insulin to regulate the metabolism of glucose and other nutrients. Researchers have been working for years to develop an artificial pancreas in the lab to help the millions of people with type 1 diabetes. But what if the answer is to "recycle" the more than 300 human pancreata from organ donors that aren't currently being used? Researchers now report on the potential to use human pancreata as the "hardware" of a new-generation, bio-artificial pancreas. Currently, about 25 percent of the approximately 1,300 pancreata recovered for transplant cannot be used due to defects and other reasons. "We see these unused organs as potential 'hardware." The 'software' would be the patient's own cells, so that there would be no issues with rejection. We believe this research represents the first critical step toward a fully human-derived artificial pancreas."
The goal of the research was to test the suitability of pancreata from organ donors as a platform for building a new bio-artificial pancreas. First, the discarded organs were washed in a mild detergent to remove all cells, a process that is known as decellularization. A similar procedure is being used by regenerative medicine researchers in efforts to engineer human kidneys, livers and intestine. For the study, 25 human pancreata were processed to remove cells. The researchers found that the framework of blood vessels remained intact after the washing process. In addition, the researchers are the first to report that numerous growth factors were retained in the structures. Some of these proteins are essential in blood vessel formation, cell proliferation and glucose metabolism.
In theory, these organ structures could be re-populated with a patient's own cells. Insulin-producing cells could be generated from the patient's skin cells or could come from the patient's pancreas. Cells to line the organ's blood vessels (endothelial cells) could also come from the patient's pancreas. To test the compatibility of the decellularized structures and new cells, the researchers placed both insulin-producing and endothelial cells on the decellularized structures. In both cases, the organs structures were cell-friendly and allowed the cells to attach, function and maintain their original cell type. Next, to test the ability of the structures to grow new blood vessels, small samples of the cell-coated pancreata structures were implanted in chicken eggs. The structures integrated well with the developing environment of the chicken egg and generated capillaries.