The pioneering transplant of a windpipe stripped of its cells and seeded with recipient stem cells has given a 30-year old Colombian woman a new lease on life, researchers report.
The operation is the first of its kind, and shows that adult stem cells combined with re-engineered biological materials can "radically improve the ability of surgeons to treat patients with serious diseases," said Martin Birchall, a professor at the University of Bristol in Britain, and one of the study’s authors.
"We believe this success has proved that we are on the verge of a new age in surgical care," he said. The loss of a normal airway is devastating, and attempts to replace them have met with serious problems such as rejection by the immune system, the uncontrolled die-off of cells, called necrosis, and lethal bleeding.
Patient scared, but trusted doctors
Claudia Castillo, stricken with tuberculosis, was facing the loss of her left lung after the tube-like branch connecting it to the trachea, or windpipe, became infected and collapsed beyond repair. Doctors explained that they could try an untested method to replace the ruined airway.
"I was scared at the beginning because I was the first patient, but had confidence and trusted my doctors," Castillo said. "The possibility of avoiding the removal of my entire lung – and instead replacing only my diseased bronchus – represented a unique chance for me to return to a normal life."
How the operation was done
With her green light, a team of scientists and surgeons from Spain, Italy and Britain each contributed olonizedd knowledge to the task. Using a new technique developed at the University of Padua, scientists remove all the cells from the trachea of a 51-year old donor by essentially scrubbing it clean with a high-tech detergent solution.
The next steps were to reconstitute the living tissue using Castillo’s own cells, and graft them onto this biological scaffolding. Stem cells were obtained from her bone marrow, and cultivated in large numbers in Birchall’s laboratory in Britain. They were then coaxed –using growth-stimulating proteins – into becoming structure-giving cartilage cells using a method originally devised for treating osteoarthritis.
The surface of the donor’s sterile trachea was seeded with these lab-grown cells using a bioreactor that allowed them to migrate into the tissue.
Next the trachea was olonized with epithelial cells, which help the major airways keep clean by moving foreign objects away from the lungs. Finally, Castillo’s damaged airway was surgically removed and replaced with the rebuilt windpipe.
Patient home after 10 days
The operation was entirely successful, the authors report. "Within four days after transplantation, the graft was almost indistinguishable from adjacent normal bronchi," said Paolo Macchiarini, a professor at the University of Barcelona, where the operation was performed, and lead author of the study.
And only ten days after surgery, Castillo left the hospital to rejoin her two children, aged 15 and four.
"We think that this first experience represents a milestone in medicine and hope that it will unlock the door for a safe and recipient-tailored transplantation of the airway in adults and children,” the authors conclude.
For Castillo the results are already tangible: "I am now enjoying life and am very happy my illness has been cured," she said.
Restoring sight and hearing
In two related studies out this week, researchers report that stem cells from tiny embryos can be used to restore lost hearing and vision in animals, in what may be a first step toward helping people facing the same difficulties.
One team repaired hearing in guinea pigs using human bone marrow stem cells, while another grew functioning eyes in tadpoles using frog cells.
While there are no immediate uses for humans, they said their findings help describe some of the most basic biological processes underlying the development of hearing and sight, and may help in the development of the new field of regenerative medicine.
"These discoveries illustrate stem cell research's continuing extraordinary potential to treat a wide range of deadly and disabling diseases that affect millions," said Anand Swaroop, a stem cell researcher at the US National Eye Institute, one of the National Institutes of Health.
Guinea pigs hear again
Dr Sujeong Jang of Chonnam National University in Gwang-ju, South Korea, and colleagues used mesenchymal stem cells from human bone marrow to restore hearing in guinea pigs whose hearing had been destroyed using chemicals.
They grew the stem cells into neuron-like cells in lab dishes and then transplanted them into the inner ears of the guinea pigs. Three months later, the animals appeared to have some hearing, Jang told a meeting of the Society for Neuroscience.
Jang said the goal was to regrow the tiny hair cells that are essential for mammals to hear, although she is not sure yet how the stem cells made this happen.
They would eventually like to try something similar in humans, Jang told a news conference.
"When sensitive hair cells in the inner ear of humans and other mammals are killed - by loud noise, autoimmune attack, toxic drugs, or aging - the damage is permanent," Jang said in a statement.
"Birds and reptiles are luckier. Their damaged hair cells apparently regenerate and can restore normal hearing."
Frogs get new eyes
Michael Zuber and colleagues at the SUNY Upstate Medical University in Syracuse, New York, grew functioning eyes in blinded frog embryos using stem cells.
Usually, frog stem cells just form skin when grown in a dish. Zuber's team added seven different genetic "factors" that turned on eye formation genes.
When they transplanted the transformed cells into frog embryos, the resulting tadpoles could see out of those eyes, Zuber told the meeting.
They tested the tadpoles by putting white tissue paper over their tank, Zuber said in an interview. Normal tadpoles will stay in the lighter side of the tank, covered by the white paper.
He showed video of blind tadpoles swimming randomly around the tank while the tadpoles with the transplanted cells stayed on the light side.
Genetic tests showed that the stem cells had transformed, a process called differentiation, into many different cell types.
"All the cells that make an eye are in there," Zuber said.
He does not see any immediate uses for people but noted that regrowing many different cell types is the goal of regenerative medicine.
"The retina, like all body organs, contains multiple, distinct cell types. Therefore, successful recovery from blindness due to injury or disease will require the functional replacement of multiple retinal cell types," he said.
Mammoths don't give you a lung when you need it for breathing... but maybe for eating 
