In a laboratory setting, scientists have successfully grown human intestine that they believe will prove beneficial to cancer patients and those suffering from stomach problems. The findings of this study were published in the Nature Medicine journal.
Using adult stem cells, scientists grew tissue fragments known as organoids that are three-dimensional organ buds capable of developing into tissues with specific functions. After being transplanted in mice, substantial amounts of fully-functioning human tissue were produced.
According to Dr. Michael Helmrath, lead scientist who works with the Intestinal Rehabilitation Program at Cincinnati Children’s Hospital, this breakthrough could have many different implications. For one, it opens the door to studying the various conditions that cause intestinal failure, to include cancer, Crohn’s disease, and even genetic disorders that appear at birth.
However, the longer-term goal of growing tissues that can replace damaged human intestine is advanced by studies such as this. To get the desired outcome, scientists first created pluripotent stem cells (iPSCs) by genetically engineering human skin cells and blood, which are stem cells that revert to an immature embryonic state. Similar to stems cells extracted from early stage embryos, IPSCs can become any type of tissue.
Scientists then grafted the organoids onto the kidneys of laboratory mice, which produced blood supply for cells to grow and multiply on their own accord into human intestinal tissue. To increase surface area and recesses known as crypts that contain intestinal stem cells that renew stomach lining weekly, inward protruding finger-like villi was included.
After a six-week period, bundles of cells within the kidneys were larger but they had also grown into the kind of tissue needed to carry out vital function such as absorption and digestion in humans. In addition, organoids developed layers of muscle used to push food through the stomach, as well as nerve cells that cause muscles to contract.
Because the mice were genetically altered so their immune system would accept human tissue, bundles of cells were not rejected. Scientists believe that treatments using IPSCs in the future that come from a patient’s own skin cells would eliminate any risk of transplant rejection but also the high cost of anti-rejection medicine taken for life.