Made-to-measure lungs grown in laboratory a step closer

Doctors believe the technique will dramatically improve survival rates of lung disease patients and solve the shortage of organs for transplantation.
The technique could be used to recycle thousands of donated organs which, at present, are considered too old or damaged for transplantation.
The manufactured lungs should be better than those directly taken from donors as they will be "rejuvenated" using the patient's own cells, removing the need for powerful drugs to prevent the body rejecting the organ.
Professor Laura Niklason and her team at Yale University have moved the technique closer to reality by making it work in rats.
"We succeeded in engineering an implantable lung in our rat model that could efficiently exchange oxygen and carbon dioxide, and could oxygenate haemoglobin in the blood," she said.
"This is an early step in the regeneration of entire lungs for larger animals and, eventually, for humans."
Lung disease is the second biggest killer in the UK accounting for more than 100,000 deaths a year. Worldwide 11.9 million people die each year.
Because lung tissue rarely regenerates the only treatment is organ transplantation which is highly susceptible to rejection and achieves only 10 per cent to 20 per cent survival rates after 10 years.
The new technique works by effectively chemically stripping the old lung down to its basic "scaffold", or exoskeleton.
On to this frame of connective tissue and blood vessels, the new lung is regrown using stem cells from the patient or from embryos. What is effectively a new lung is then transplanted back into the patient.
At the moment, the technique will require donor organs, but it is hoped that eventually pig lungs or artificial scaffolds can be used instead.
The technique is similar to one used in replacing the windpipe of Claudio Castillo two years ago in Spain, but because the lung is a more complicated organ it has taken longer to develop.
Prof Niklason carried out the technique in rats and was able to get the new organs to 'breathe' – exchanging oxygen and carbon dioxide.
The researchers say this is an important first step but a great deal more research must be done to see if fully functional lungs can be regenerated in the lab and be long-lasting in humans once implanted.
Prof Niklason says for this technology to be applicable to patients, it is likely that years of research with adult stem cells will be needed to repopulate lung matrices and produce fully functional lungs.