In tissue engineering this is the age of organoids: while the challenge of generating a blood vessel network sufficient to grow large tissue sections is not yet solved, researchers are nonetheless establishing the diverse set of methodologies needed to grow functional organ tissue from a cell sample. The recipe is different for every tissue type, and there are many forms of tissue in the body. The resulting small tissue sections are known as organoids. At this time organoids are largely used to speed up further research, but for some tissue types there is the potential to produce therapies based on transplantation of multiple organoids to patch or augment failing organs. Sadly, that is probably not an option for lung disease due to the highly structured nature of lung tissue, and here the focus is on using organoids to improve the state of research. A number of groups have demonstrated functional lung organoids of increasing sophistication in the past few years, and here is the latest example in this line of research:
New lung "organoids" have been created from human pluripotent stem cells. Researchers used the organoids to generate models of human lung diseases in a lab dish, which could be used to advance our understanding of a variety of respiratory diseases. Organoids are 3-D structures containing multiple cell types that look and function like a full-sized organ. By reproducing an organ in a dish, researchers hope to develop better models of human diseases and find new ways of testing drugs and regenerating damaged tissue. "Researchers have taken up the challenge of creating organoids to help us understand and treat a variety of diseases. But we have been tested by our limited ability to create organoids that can replicate key features of human disease."
The lung organoids created in this study are the first to include branching airway and alveolar structures, similar to human lungs. To demonstrate the functionality of the organoids, the researchers showed that the organoids reacted in much the same way as a real lung does when infected with respiratory syncytial virus (RSV). Additional experiments revealed that the organoids also responded as a human lung would when carrying a gene mutation linked to pulmonary fibrosis. RSV is a major cause of lower respiratory tract infection in infants and has no vaccine or effective antiviral therapy. Idiopathic pulmonary fibrosis, a condition that causes scarring in the lungs, causes 30,000 to 40,000 deaths in the United States each year. A lung transplant is the only cure for this condition. "Organoids, created with human pluripotent or genome-edited embryonic stem cells, may be the best, and perhaps only, way to gain insight into the pathogenesis of these diseases."