Investigations continue into what can be done with comparatively simple transplantation of various different types of stem cell:
Damaged or diseased organs may someday be healed with an injection of blood vessel cells, eliminating the need for donated organs and transplants, according to scientists. Researchers show that endothelial cells - the cells that make up the structure of blood vessels - are powerful biological machines that drive regeneration in organ tissues by releasing beneficial, organ-specific molecules. They discovered this by decoding the entirety of active genes in endothelial cells, revealing hundreds of known genes that had never been associated with these cells. The researchers also found that organs dictate the structure and function of their own blood vessels, including the repair molecules they secrete.
"Our work suggests that that an infusion of engineered endothelial cells could engraft into injured tissue and acquire the capacity to repair the organ. These studies - along with the first molecular atlas of organ-specific blood vessel cells - will open up a whole new chapter in translational vascular medicine and will have major therapeutic application. Scientists had thought blood vessels in each organ are the same, that they exist to deliver oxygen and nutrients. But they are very different." Each organ is endowed with blood vessels with unique shape and function and delegated with the difficult task of complying with the metabolic demands of that organ.
The scientists postulated that endothelial cells derived from embryonic stem cells [are] able to be taught how to act like an organ-specific blood vessel, [and the] team generated endothelial cells from mouse embryonic stem cells that were functional, transplantable and responsive to microenvironmental signals. These embryonic-derived endothelial cells "are versatile, so they can be transplanted into different tissues, become educated by the tissue, and acquire the characteristics of the native endothelial cells."
Researchers can propagate these cells in large numbers in the laboratory. "We now know what it takes to keep these cells healthy, stable and viable for transplantation." The researchers transplanted these generic endothelial cells [into] the liver of a mouse and found that [they] became indistinguishable from native endothelial cells. This also occurred when cells were grafted into kidneys. "These naive endothelial cells acquire the phenotype - the molecular profile and signature - of the native pre-existing endothelial cells due to the unique microenvironment in the organ. These transplanted endothelial cells are being educated by the unique biophysical microenvironment organ in which they are placed. They morph into endothelial cells that belong in the organ, and that can repair it. If you have a heart injury and you need to reform some of your cardiomyocytes, the endothelial cells that are around the heart secrete factors that are specific for helping a heart repair itself."