Researchers have made stem cells grow into tiny three-dimensional bits of lungs. The tiny pieces of lung, called organoids, were grown in a dish and mimic the complexity of the lungs. They may allow scientists to research how lung tissue responds to disease and treatments.
Before this development, researchers were only able to grow lung tissue on a scaffold or structure made from a donated piece of lung. In this research, the stem cells and the cells they create organized themselves into lung organoids, which are three dimensional and which mimic the structure and complexity of the human lung.
Stem cells are cells that have the potential to develop into many different types of cells in the body during early life.
The researchers were able to get the stem cells to grow into structures that resemble the airways in the lungs called bronchi and the air sacs in the lungs called alvioli. However, the organoids do not have vital parts such as blood vessels. Blood vessels in the lungs pick up oxygen in the alveoli and exchange it for carbon dioxide during breathing.
"These mini lungs can mimic the responses of real tissues and will be a good model to study how organs form, change with disease, and how they might respond to new drugs," says senior study author Jason R. Spence, Ph.D., assistant professor of internal medicine and cell and developmental biology at the University of Michigan Medical School and a senior author on the study.
To make the lung organoids, the researchers manipulated signals within the stem cells that control formation of organs. They coaxed the stem cells to form a type of tissue called endoderm and then coaxed this tissue to become tissue that resembles pieces of embryonic lung. This lung tissue then spontaneously formed into three-dimensional structures that were able to survive in the lab for more than 100 days.