London, (Agencies): As scientists have come up with a way to grow new human veins in the laboratory, off-the-shelf blood vessels could soon be a reality.

According to the researchers, the lab-made blood vessels, which can be stored for up to a year and safely transplanted into any patient, could revolutionise heart surgery.

They also claimed the blood vessels could soon replace artificial versions -- which easily clog and cause infection -- in a number of operations, including thousands of heart bypasses a year.

Scientists have already developed a technique to engineer blood vessels from a patient's own cells, but this process takes over nine months and patients usually cannot wait that long for surgery.

The new technique developed in US, involved making the vessels in advance by using random donor cells from human tissue to grow collagen on a biodegradable "scaffold" tube or mould made from a polymer.

When the scaffold dissolves away, fully formed blood vessels are left behind. These are then "washed" of the original human cells so that they were completely benign and unlikely to cause any rejection in the body of a recipient, the researchers reported in the journal Science Translational Medicine.

These vessels have already been tested on baboons and were found to work by fully restoring blood flow. There were no evidence of clogging or thickening when the grafts were removed after six months -- an indication that they would be suitable for long term transplantation.
The new "bioengineered" veins appear to avoid these complications. The new veins could also be used to help kidney dialysis patients whose own blood vessels become damaged by the treatment, the researchers said.

Shannon Dahl, lead author of the study, however, said there is still considerable research to be done before a product is available for widespread use.