Renal Insufficiency: Blood vessels made in the laboratory
Human blood vessels developed in the lab have been successfully transplanted to human circulatory systems. The blood vessels come from the recipient’s own tissues and could be used to replace arteries damaged by kidney disease.
A team of researchers based in Durham, North Carolina, grew blood vessels using human smooth muscle cells, found in arteries and veins.
These cells were spread over a scaffold and supplied with nutrients. They produced an extracellular matrix, a 3D network of proteins, including collagen, to make blood vessels. When the vessels formed, fluids were introduced into them to simulate the pressure of the blood being pumped through the body.
The researchers separated the cells from the vessels, removing proteins that could be recognized as foreign by the recipient’s immune system. They then implanted the 42 centimeter long and 6 millimeter diameter vessels in the arms of 60 people with kidney failure.
Samples taken from 13 people over a four-year period showed that the blood vessels developed into multi-layered, self-healing tissues after injury, thus truly becoming the person’s own vessels.
Blood vessel replacements are necessary in many situations, such as when the arteries are damaged by trauma or cardiovascular disease. Coronary artery bypass surgery, for example, involves the transplantation of vessels to restore normal blood flow to the heart.
The advantage of bioengineered vessels over synthetic polymer implants is that they showed no signs of rejection or inflammatory reactions.
It took about two months for a batch of blood vessels to grow in the lab. The team is now stepping up the process, hoping to produce tens of thousands a year.