In studies appearing in recent issues of Stem Cell Journal and Developmental Cell, the 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.
"Scientists had thought blood vessels in each organ are the same, that they exist to deliver oxygen and nutrients. But they are very different," and 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, Dr. Rafii adds.
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," Dr. Nolan says.