Blood Vessel Cells May be Able to Regenerate and Repair Organs

Could we one day regenerate organs? Scientists are looking at new ways to do so. They've discovered that endothelial cells, which are 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.

In order to find out a little bit more about endothelial cells, the researchers conducted a series of studies. In one, the scientists examined nine different tissues at homeostasis, a steady, healthy state. They also examined liver and bone marrow recovering from a traumatic injury. From these cells, the researchers were able to take a snapshot of all the genes that were expressed in the various populations of endothelial cells, known as vascular beds. In the end, they found that endothelial cells possess tissue-specific genes that code for unique growth factors, adhesion molecules and factors regulating metabolism.

"We knew that these gene products were critical to the health of a particular tissue, but before our study it was not appreciated that these factors originate in the endothelial cells," said Daniel Nolan, one of the researchers, in a news release.

The findings actually raised the question as to how endothelial cells have the capacity to adapt to the biological demands of each organ. Would it be possible to design "immature" endothelial cells that could allow scientists to develop more specialized cells? That's what they wanted to find out.

In another study, the researchers generated endothelial cells from mouse embryonic stem cells that were functional, transplantable and responsive to microenvironmental signals. In fact, the embryonic-derive endothelial cells were versatile and could be transplanted into different tissues.

"These transplanted endothelial cells are being educated by the unique biophysical microenvironment organ in which they are placed," said Sina Rabbany, one of the researchers, in a news release. "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 cardiomycytes, the endothelial cells that are around the heart secret factors that are specific for helping the heart repair itself."

That's not to say that endothelial cell transplant is human is currently possible. However, scientists are hopeful for the future. The cells could potentially be used as "Trojan horses" to block tumor growth or could even be altered to block toxic chemicals. The findings from these studies are a huge leap forward for the field of medicine.

The findings are published in the journals Developmental Cell and Stem Cells.