Batista et al. Nature.
Key to scientific progress is the ability to test new treatments in animals that represent the human disease of interest or in cells in the laboratory that represent the human disease. The better these test systems represent the human disease, the more likely it is that approaches successful in the test systems will actually work in the clinical trials. An example of test systems not being truly representative of human diseases are the animal models of cancer. Literally thousands of drugs, vaccines and other approaches have been demonstrated to cure cancer in mice, but when tested in humans do not work.
Stem cells are now being used to create in vitro (in the lab) models of human diseases. One way in which this is occurring is by creating stem cells from skin or other adult tissues of people with diseases. Specifically, the process of generating iPS cells allows for creation of cells that resemble embryonic stem cells from practically any adult tissue. Thus if one wanted to study drugs that affect lung function in patients with cystic fibrosis, one could take a small skin sample of a cystic fibrosis patient, generate iPS cells, and use these cells in vitro to create human lung tissue that would be similar to the lung of the original cystic fibrosis patient. This way one could take the artificially generated tissue and test drugs on it. Prior to the creation of iPS cells, something like this would have required taking out lung specimens from cystic fibrosis patients, something which would definitely not be ethical !
In the study discussed today (Batista et al. Telomere shortening and loss of self-renewal in dyskeratosis congenita induced pluripotent stem cells. Nature. 2011 May 22) investigators studied the rare disease dyskeratosis congenita. This condition is associated with accelerated aging.
The study demonstrated that iPS cells from dyskeratosis congenita patients possess the exact same biochemical defects characteristic of the disease and when patients with different severity of the disease were used to generate iPS cells, the more advanced the disease was, the less telomerase activity was found in the cells.
Mimicking Human Diseases in Cells: iPS Cells Used to Create Model of Extremely Rare Condition Dyskeratosis Congenita
Batista et al. Nature.