lab-grown lungs

The Scientist | Two new lab-grown versions of lungs may one day serve as a way to sidestep both animal testing and organ transplantation.

One engineered rat lung, described in Science Express today (June 24), even successfully helped rats breathe for brief periods.

"This is the first ever published paper that really demonstrates that regenerative medicine can provide an alternative to clinical transplantation of the lungs," said translational medical researcher Paolo Macchiarini of Karolinska Institutet in Sweden, who was not involved in the research.

Currently, the only treatment for the lung diseases that cause some 400,000 deaths each year is to transplant a new, healthy organ -- a procedure that is hampered by organ rejection complications and a severe shortage of donors. But now, bioengineer and vascular biologist Laura Niklason of Yale University and her colleagues may have developed a way to eventually address both of these issues.

Treating adult rat lungs with detergent solutions to remove their cellular components gave the researchers their starting point -- a lung skeleton, or the extracellular matrix that gives the lungs their structure. The team then repopulated the lungs with epithelial and endothelial cells from rat lungs, which grew over the scaffolds to create brand new lungs.

The researchers then implanted the new lungs into rats for up to two hours, during which time they found evidence that the engineered lungs were successfully participating in gas exchange. However, they also started to see some blood clots form in the vasculature of the lungs, as well as small amounts of leakage of blood into the airways, which most likely stemmed from an imperfect matrix and incomplete covering of new cells, Niklason said.

"Clearly we're close, but not all the way there yet," she said. "We really view this work as laying a scientific and technological basis for regenerating lungs in the long term."