Again we are solving the practical problems regarding stem cell therapy. Before it is finished, it is clear that stem cell technology will allow all forms of tissue replacement as a matter of course.
Key to the research is the similarity between stem cells in the lung and those in bone marrow. In both cases, the cells are located in specialized, provision-filled compartments, rather than being distributed throughout the tissue. The team began work on the assumption that existing knowledge of transplanting bone marrow stems cells might be relevant when working with the lungs.
In the case of bone marrow, two principles are key. First is that the specialized stem cell compartment must be clear before the transplant is carried out, and second is that the cells have an innate ability to find their way to said compartment.
To see if the treatment was effective when working with damaged lungs, the researchers first obtained embryonic stem cells in their 20th to 22nd week of development. Harvesting cells at this young age is deemed optimum, as they've not yet completed the process of differentiation, and are more effective at regenerating damaged tissue than older stem cells. Working with mice suffering with damaged lungs, the team then cleaned out the specialized compartments, and introduced the embryonic stem cells to the tissue.
As hoped, the cells exhibited similar behavior seen in bone marrow stem cell treatment, finding their way through the bloodstream and into the compartments. After some six weeks, the cells had formed into normal lung tissue, significantly healing the damaged tissue and notably improving the rodents' breathing.
In light of the successful tests, the team will continue its research, and will work to pinpoint the ideal dosage of drug required to ensure that the host doesn't reject the transplanted stem cells. In the long run, the goal is to cultivate a bank of lung tissue that can be used as a resource for embryonic stem cells, making it easier to carry out the treatment in the real world.
Source: Weizmann Institute of Science