Old cells grow new blood vessels in lab
Human blood vessels can be grown from an elderly patient's own cells and may lead to new treatments for heart disease within the next decade, say US scientists.
"We took vascular cells from four elderly men with heart disease and engineered new blood vessels," says Niklason.
The researchers grew blood vessels in the laboratory from cells taken from four men aged 47 to 74 who were having coronary bypass surgery.
Cardiovascular disease is a leading cause of death in developed countries and growing vessels from the patient's own cells should alleviate the problem of rejection by the patient's immune system.
Although the blood vessels are not strong enough to be implanted in patients, the researchers say the study presents "a proof of principle". With more research they believe they can overcome the problem and ensure the safety of the procedure.
"We still have a couple of more stepping stones to get these vessels ... to be functional enough so they can survive in the patient," Niklason says.
She and her team removed muscle and endothelial cells from the saphenous vein, which is often used to bypass blockages in the arteries around the heart, in the patient's lower leg. Endothelials are cells that line the inside of blood vessels.
Genes injected to extend cells life
A key to the whole process was the injection of a gene into the cells to make them essentially live and divide forever. Without that telomerase gene, the cells would divide only a small number of times in the lab and then stop growing.
"The lifespan extension strategy is potentially important for tissue engineering of a lot of other tissues," Niklason says. "It is a globally enabling step."
After the cells were grown in the lab, they were placed on a sponge-like biodegradable polymer tube. Vitamins and nutrients were pulsed through and around the tube to mimic conditions in the body.
As the muscle cells proliferated and the tube dissolved, the scientists added the endothelial cells to complete the vessels which were grown for up to seven weeks.
In a commentary in the journal, Dr Eric Brey and Dr Howard Greisler of Loyola University Medical Center in Illinois describe the research as an important advance in tissue engineering.
"The researchers provide a degree of optimism for the feasibility of clinical applications of engineered blood vessels," they say.
Making blood cells
In related news, Australian scientists, led by Dr Andrew Elefanty of Monash University in Melbourne, report in the journal Blood that they have found a way to make blood cells in volume out of human master cells.
This could eventually lead to production of safe blood cells for transfusions and organ transplants.
Synthetically produced red blood cells would, in theory, overcome the concerns about dangerous infections that can be transmitted from blood donors to patients worldwide.