Stem cell research: Two steps forward, one step back
Several research papers have just been published about stem cells and their use for treating disease.
In a stem cell step forward, Christine Chaffer and colleages at the Whitehead Institute overturned a long-held belief that cell differentiation only moves forward – that is stem cells become specific cell types, but not the other way around.
Specifically, they discovered a differentiated cell type found in breast tissue that could spontaneously become like a stem cell.
One clear lesson learned from the research, published online on April 26 in the Proceedings of the National Academy of Sciences, is the need to make sure that cancer treatments should not just target cancer stem cells, as some therapies do, but should really ensure that all the cancer cells are gone since any remaining cancer cells can change back into cancer stem cells. These cancer stem cells can then ''seed'' tumors at the cancer site as well as in other parts of the body.
Another lesson learned from the research is that it may be possible to obtain adult stem cells from patients which can then be used to treat degenerative diseases.
The second stem cell step forward is the identification of a human lung stem cell that can form the different structures of the lung: bronchioles, alveoli and pulmonary vessels.
Piero Anversa, director of the Center for Regenerative Medicine at Brigham and Women's Hospital and corresponding author for the research, highlighted the importance of their finding for the treatment of chronic lung diseases.
The research, published in the May 12, 2011 issue of the New England Journal of Medicine, involved the identification and isolation of the human lung stem cell. After isolating the stem cells, the researchers showed that the cells were capable of two things: dividing into new stem cells, and growing into the different kinds of cells that make up the lungs. To do the latter, they injected the stem cells into lab mice with damaged lungs. The mice were able to grow the threee different kinds of lung tissue which attached to the mice's existing lung tissue. A third thing the researchers were able to do was to re-extract stem cells from the treated mice and then use the extracted stem cell to ''heal'' more mice.
However, like the frog taking two steps forward but falling one step back in his quest to climb out of a water well, stem cell research got a blow when another long-held belief was blown to bits: that stem cells derived from a person would not cause any immune rejection response since the cells are the person's own.
That's right, a person's own stem cells can cause immune rejection problems according to researchers at University of California San Diego.
Induced pluripotent stem cells (iPSCs) were considered as good candidates for stem cell therapy because of the belief that the body would not attack them or try to get rid of them. But tests on lab mice comparing their immune response to embryonic stem cells and iPSCs found that both kinds of stem cells were rejected.
Thus, researchers conclude that treating a patient with his own iPSCs could cause immune responses. This third research was published in the May 13, 2011 issue of Nature.
But of course, even this step back is a step forward in the race of the human race to find ways to heal and jump out of the well of human diseases.
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