The Hindu : International : Blood vessels from cells

Online edition of India's National Newspaper
Friday, Jun 17, 2005

International

International

Blood vessels from cells

These could now be made from cells of older people for heart surgery

LONDON: Scientists have grown blood vessels using cells taken from sick older people — the type of patients most likely to need such transplants if the technique is perfected. The approach, outlined in The Lancet journal, could be used for heart or other bypass surgery.

Currently, doctors fix a blockage in a coronary artery by sewing in a new strip of blood vessel so that the blood flow bypasses the blockage. The new vessel usually comes from a vein in the leg.

However, in elderly people, the leg veins are often not good enough to be used in the chest and often the patients have had previous bypass surgery and do not have many suitable leg veins left for the next operation.

Synthetic grafts are available, but are not that effective for small blood vessels, said a biomedical engineer from Chicago's Illinois Institute of Technology who was not connected with the research but said the study was an important advance in tissue engineering.

Scientists have grown human blood vessels before, but from young, healthy cells. "The ability to grow new vessels from older cells represents a crucial initial step toward growing blood vessels from a patient's owns cells that can be used to treat that patient's vascular disease," said lead researcher Dr. Laura Nikalson, an associate professor of anesthesiology and biomedical engineering at Duke University in North Carolina.

In the study, the blood vessels were engineered using cells taken from the leg veins of four elderly men with heart disease who were having bypass operations.

Growing the blood vessels from older cells is an advance because cells from older people do not proliferate as successfully because they do not have enough life cycles left to be grown into functional arteries, experts say. But in the study, the scientists found a way to overcome that limitation by treating them with a chemical involved in cellular aging.

To create the arteries, the researchers made a tube from a sponge-like material and impregnated smooth muscle cells along the tube, then pulsed a vitamin and nutrient solution through it until the cells filled the spaces in the dissolving scaffold.

They then added cells of a different type to line the interior of the blood vessels to complete the artery. While the vessels looked right, they were not strong enough to be implanted into humans.

Much of the strength of blood vessels is down to other elements between and around the cells, such as collagen and elastin. This is the next major hurdle in the work. "Once you implant these vessels, if they are not strong enough you are going to have serious problems. My gut is that it's not trivial to overcome," said the engineer.

The researchers said the technique could be perfected within the next 10 years.

— AP

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