Stem Cells Used to Grow the Cells That Line Blood Vessels

Scientists at Harvard University were able to use human stem cells to grow vascular endothelial cells -- the type of cells that line blood vessels. The breakthrough has led to the discovery of new details of how these cells function.

The researchers used human induced pluripotent stem cells (iPSCs) to grow the blood vessel linings in a novel way, inducing the differentiations of the iPSCs into specific cell types by mimicing the flow of blood. The cells which received a strong "flow" grew into artery cells, while those exposed to a weaker flow grew into vein cells.

"It was especially exciting to us to discover that these cells are basically responding to biomechanical cues," said research leader Guillermo García-Cardena.

"By exposing cells to 'atheroprone flow,' we can direct differentiation of these cells into cells that are present in areas of the circulatory system that we know are affected by diseases like atherosclerosis."

By studying the iPSC-derived human endothelial cells, the research team found three critical functions carried out by mature endothelium in the body: mounting inflammatory responses, keeping blood from leaking out of the blood vessel, and preventing blood clots.

The find could lead to enhanced safety for patients needing kidney dialysis or lung failure treatment by reducing or eliminating the need for the anticoagulant heparin. In addition to causing some rare but serious side effects, heparin thins the blood and can also cause loss of blood and internal bleeding, all of which can interfere with the body's healing process.

"The iPSC-derived endothelial cells cells beautifully function as an anticoagulant surface," García-Cardena said. "In the future, we may take a tissue sample from a patient, generate iPSCs, and then cover an extracorporeal device with the patient's own endothelial cells-so the patient can go home with the device without the need for regular heparin shots."

García-Cardena and his colleagues' research is published in the journal Stem Cell Reports.