Grow your own: the race to create body parts in the lab
From replacement skin to entire new organs, regenerative medicine is finally leaving its early scandals – and the controversial ‘earmouse’ – behind. Could it one day provide a cure for birth defects, blindness and diabetes?
By Hannah Devlin
Dec 5 2017
Two years ago, Hassan’s father was faced with questions that he had no good answers for. “Why do I have this disease?” his seven-year-old son asked him. “Why do I have to live this life?”
Hassan was born with a rare genetic skin condition, called epidermolysis bullosa, that causes fragile, blistering skin. His first blister appeared when he was a week old, but soon after his family fled their native Syria and arrived as refugees in Germany, things got much worse. By June 2015, Hassan was admitted to hospital, critically ill, having lost the skin from almost the entire surface of his body. “Except for his face, hands and feet, he didn’t have any skin left,” his father recalls.
Having run out of conventional treatments, his doctors were preparing to start palliative care. But, as a last resort, they contacted an Italian scientist, Michele de Luca, who had carried out genetically modified skin transplants – but on nothing approaching this scale.
In a remarkable scientific breakthrough, De Luca’s team went on to grow an entire replacement skin for Hassan. It was grafted on, like a patchwork quilt, and after spending months bandaged from head to toe, Hassan emerged effectively cured of his devastating illness. Two years on, he is well, his skin no longer blisters, he needs no medication or ointments, he plays football and, when he gets a cut, he heals normally.
“It felt like a dream for us,” the boy’s father says.
De Luca says that witnessing the recovery produced “one of the strongest emotions in my whole life … For a scientist working in this field, having these results justifies an entire career.”
It also marked a rare and long-awaited clinical success for the field of regenerative medicine, which has faced criticism for delivering just a handful of therapies after years of hype.
Scientists first succeeded in culturing human embryonic stem cells in 1998. The cells, extracted from donated IVF embryos, can divide and multiply indefinitely and morph into any other cell type in the body. The advance raised the prospect of limitless supplies of lab-grown cells – blood, liver, skin – and ultimately spare organs and body parts, grown from scratch in the laboratory. The image of the infamous “earmouse”, published a year earlier, seemed to hint that scientists were already on the brink of such capabilities. In fact, the “ear” was cow cartilage and no human cells were involved, but the seed of expectation was sown.
De Luca says that, from the start, there was an unrealistic sense of how quickly therapeutic uses would arrive, fuelling frenzied competition within the field, and people taking shortcuts or, worse, falsifying results.
Most notorious among these was Paolo Macchiarini, an Italian surgeon, who was feted as a medical superstar when he claimed in 2011 to have successfully transplanted the world’s first synthetic windpipe, a plastic scaffold seeded with a patient’s own stem cells. The remarkable story later unravelled as it emerged that seven (now eight) of the nine patients to receive the synthetic tracheas had died and, last year, Macchiarini was fired from Sweden’s Karolinska Institute for misconduct.
“The Macchiarini case was detrimental to the entire field, but we should not generalise,” says De Luca. “We don’t have to stop doing regenerative medicine, even in that specific field, because of what happened. We just have to do things properly.”
De Luca’s next project, a collaboration with scientists at Great Ormond Street Children’s hospital in London, aims to create a functioning oesophagus, the food pipe, from a pig organ that has been decellurised – a process in which all the cells and genetic material are washed away – and lined with human stem cells taken from patients.
Growing skin required scientific ingenuity, but the oesophagus also presents a substantial engineering challenge. The organ comprises a tube of smooth muscle covered by the internal skin, or epithelium. It must be rigid enough to stay open, but be able to contract to squeeze down food, and, without a blood supply, necrosis – or cell death – will set in.