Lab-grown mini lungs have been transplanted into immunosuppressed mice to study respiratory diseases such as asthma.
"In many ways, the transplanted mini lungs were indistinguishable from human adult tissue," said senior study author Jason Spence, Associate Professor at University of Michigan Medical School in the US.
Respiratory diseases account for nearly one in five deaths worldwide, and lung cancer survival rates remain poor despite numerous therapeutic advances during the past 30 years.
Lab-grown lungs can help because they provide a human model to screen drugs, understand gene function, generate transplantable tissue and study complex human diseases, such as asthma.
The researchers used numerous signaling pathways involved with cell growth and organ formation to coax stem cells -- the body's master cells -- to make the miniature lungs.
The findings, published in the journal eLife, suggest that scientists can now grow 3-D models of lungs from stem cells, creating new ways to study respiratory diseases.