It has been a week for lungs!
First of all, some guys from Harvard have developed a microchip that mimics a human lung. They did this by adding blood-vessel and lung cells in such a way that they formed the mircoscopic structures that are present in the lung.
See, scientists at the moment use tissues grown in flasks. The cells just lie on a flat surface and start growing every which way. Lungs, like many other cells, have a direction: one side faces the air surface and the other faces the blood surface. When you grow them in a flask, there’s no air surface and so, the lung cells don’t develop into normal structures.
So, the lung cells grown in flasks don’t mimic normal lung structure, which has a big influence on how the lung can absorb things like oxygen, toxins and drugs. If they did want to observe absorption of new drugs, they would have to do animal studies, which are full of animal-to-animal variation, ethical problems and are associated with high costs.
This new system grows the cells on a thin mesh, on which one side is exposed to air and on the other side a blood substitute. This means the lung cells develop into structures that resemble the normal lung structure much more and allows scientists to do more controlled studies cheaply.
In other news, over at Yale they’ve been able to grow new lungs for rats. They’ve been able to strip away all the lung cells, leaving only connective tissue and blood-vessels. Then they’ve been able to seed some lung cells from another rat onto this “lung skeleton” and been able to grow a brand-new pair of lungs. Even better, when they implanted this pair of lungs into a third rat, they worked… for 45 to 120 min. I’m actually not sure what happened after that because I don’t have access to the article, but I bet it was exciting.
Anyway, this is one step closer to replacing sick lungs in humans and treating diseases such as lung cancer, asbestosis and cystic fibrosis.