Large organ growth bid moves closer
Scientists have developed a new tissue engineering technology - overcoming one of the "major hurdles" for growing large organs.
Research led by the universities of Bristol and Liverpool found that cells can be combined with an oxygen-carrying protein to produce living tissue in the laboratory.
It is hoped this can then be implanted into patients as a way of replacing diseased parts of the body.
The technology has generally been limited to growing small pieces of tissue until now. This is because larger dimensions reduce the oxygen supply to cells in the centre.
In the breakthrough, scientists used cartilage tissue engineering as a model system for testing a new method of overcoming the oxygen problem.
The team made a new class of artificial membrane binding proteins that can be attached to stem cells.
An oxygen-carrying protein, myoglobin, was attached to the stem cells before they were used to engineer cartilage.
This meant each cell had its own oxygen reservoir that it could access when oxygen in the scaffold drops to dangerously low levels.
Dr Adam Perriman, from Bristol's School of Cellular and Molecular Medicine, said: "From our preliminary experiments, we found that we could produce these artificial membrane binding proteins and paint the cells without affecting their biological function.
"However, we were surprised and delighted to discover that we could deliver the necessary quantity to the cells to supplement their oxygen requirements.
"It's like supplying each cell with its own scuba tank, which it can use to breathe from when there is not enough oxygen in the local environment."
The findings, published in Nature Communications, could expand the possibilities in tissue engineering including in cardiac muscle or bone.
Researchers developed the method while using cartilage to grow tissue to repair large knee injuries.
However, oxygen could not reach cells in the centre of the tissue - leaving a hole in the middle of the structure.
Attaching myoglobin, which is commonly found in muscles, meant the stem cells were fully oxygenated during early stages of the growing process.
This breakthrough solved the problem of the hole and is likely to pave the way for the development of a wide range of new biotechnologies.
Professor Anthony Hollander, from the University of Liverpool, added: "We have already shown that stem cells can help create parts of the body that can be successfully transplanted into patients, but we have now found a way of making their success even better.
"Growing large organs remains a huge challenge but with this technology we have overcome one of the major hurdles.
"Creating larger pieces of cartilage gives us a possible way of repairing some of the worst damage to human joint tissue, such as the debilitating changes seen in hip or knee osteoarthritis or the severe injuries caused by major trauma, for example in road traffic accidents or war injuries."
Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue is published in Nature Communications.