London - Human blood vessels have been grown in the laboratory in a breakthrough that could revolutionise heart bypass surgery.
The DIY veins take just a few weeks to produce from skin cells removed from the hand.
As well as bypass operations, the tubes could also be used to help kidney patients on dialysis and babies with defective heart valves.
The US scientists behind the new technology say they can manufacture blood vessels in two months by weaving them on a miniature “loom” in the lab.
Previous attempts to produce man-made veins have either relied on synthetic materials or produced veins that are not strong enough.
During heart bypass surgery, a vein from another part of the body is used to divert blood around narrowed or clogged blood vessels.
But many of the 26,000 Britons in need of this delicate operation each year do not have any healthy blood vessels suitable for grafting.
Artificial versions are available but are prone to infection.
The latest technique, unveiled at the Experimental Biology conference in San Diego, should cut the odds of infection.
The DIY veins are the brainchild of researchers at US firm Cytograft Tissue Engineering. The process starts with a sample of skin cells taken from the back of the hand.
The cells, which produce large amounts of the strong but elastic protein collagen, are grown and multiplied in the lab until they form a thin sheet. The sheet of cells is then rolled up, like a roll of wrapping paper, and incubated with key nutrients until the layers fuse together to form a hollow tube.
The tube is then lined with a second type of cell, taken from a superficial vein that was part of the original skin sample.
Blood vessels up to 20cm in length have been made using a patient’s own cells and using donor cells.
Use of donor cells would allow the veins to be produced on an industrial scale and stored in fridges until they are needed.
Veins made from donor cells have been implanted into three patients with severe kidney disease, to allow better access for dialysis.
So far the transplants have been successful, with the first patient treated more than a year ago. Dr Frank Sellke, of the American Heart Association, said that despite the small number of patients in the study, the results were “very good”.
Heart surgeon Timothy Gardner, the association’s past president, added: “These are essentially off-the-shelf, ready to be used.
“The thing that impressed me was that there was no evidence of any immune response or rejection associated with it. I think it is a really interesting, promising new development.”
The process can be made quicker by cutting out the step in which the sheet of cells is rolled up and left to form a tube.
Instead, the cells are cut into fine threads, which are visible to the naked eye.
These are then rolled on to spools and woven into tube shapes on a tiny sterile loom.
Cytograft’s co-founder Dr Nicolas L’Heureux said: “What we are doing here is using a completely biological, completely human fibre from which we can now build all kinds of structures by weaving, knitting, braiding or a combination of techniques.”
Doing this slashes the time to make a blood vessel to just two months.
However, the process isn’t cheap, with each vein expected to cost several thousand pounds.
The technology, particularly that needed for the woven veins, is still at a relatively early stage and it is expected that it will be five to ten years before the DIY blood vessels are suitable for widespread use. - Daily Mail