Replacing destroyed blood vessels is a routine treatment today in many cardiovascular diseases, but in the case of small blood vessels there is no really good alternative if patients do not have veins of their own that can be used. Small vessels made of synthetic materials have a tendency to become blocked by blood clots.
This is a serious problem which has been solved by a research team at Chalmers University of Technology and Sahlgrenska University Hospital. Henrik Bäckdahl has been a member of the team from the start, when attempts were made to culture animal cells on cellulose secreted by a special bacterium, which is naturally present on rotting fruit.
Functions as scaffold for human cells
When it was found that the cells could grow on the cellulose the team came up with the idea of using it as a "scaffold" for human cells which divide and build up a blood vessel together with the cellulose after the bacteria have been removed.
Such progress has now been made that transplanting blood vessels of this kind into pigs and sheep has been tested. These animal experiments were preceded by a study by Bäckdahl and his colleagues on rats.
Accepted by the immune system
Bacterial cellulose was implanted under the skin, with the result that the animals´ own tissue grew together with the cellulose, without the immune system trying to reject it.
In order to obtain tubular cellulose, Bäckdahl let the bacteria grow on a silicone tube, which was then withdrawn.
He has also shown that it is possible to create branched blood vessels by this method. In addition, he has developed a method to control how porous the cellulose becomes.
Potential to create a number of artificial tissues
Bacterial cellulose could be used to create a number of different artificial tissues besides blood vessels.
"The material has very special properties," says Bäckdahl.
"Among other things, we have discovered that the fibres of the cellulose have the same dimensions as the body's own collagen. This may explain why implanting the material into living tissue works so well."
The thesis, entitled "Engineering the shape of bacterial cellulose and its use as blood vessel replacement", will be publicly defended on Thursday 22 May.
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