They’re Not Perfect Cells, But They’re Model Cells
In his final column for Science Progress, Rick Weiss responded to critics of stem cell research who argue that injections of stem cells will never serve as treatments for certain chronic diseases. True enough, Weiss wrote, injections of stem cells are unlikely to serve as a treatment for conditions like Alzheimer’s:
Alzheimer’s, after all, affects such a large part of the brain that treating it with injections of cells would almost certainly be futile. (Parkinson’s disease, by contrast, involves a very small area in the brain so has real of hope of being helped by injections of replacement cells there.)
But that doesn’t mean that research involving human embryonic stem cells might never play a crucial role in developing treatments for diseases like Alzheimer’s. The reason: because stem cells can develop into any kind of cell in the body, scientists can potentially use them to grow model tissue samples and test drugs without the need to experiment on a human subject.
Stem cells are powerful tools for developing treatments not just because they can regenerate damaged tissue, but because as they grow, scientists can use them to understand the basic biology of a disease.
Researchers at the University of California San Deigo have recently taken just such a step forward in their ability to understand the development of genetic diseases. The scientists substituted an altered cancer-causing gene and a gene for a rare movement disorder in the genomes of embryonic stem cells. Since embryonic stem cells perpetually renew themselves and can differentiate into any type of cell in the human body, this afforded them the opportunity to study the development and behavior of the diseases. Future research can test new drugs and therapies on these human cell models before moving to a clinical trial, making it possible to develop safe and effective drugs in a cheaper and faster manner.
The researchers note specifically in their article in Cell Stem Cell that these two hESC disease models “will become valuable resources to study human tumorigenesis and develop more effective therapeutic interventions for human cancer.”
For years, scientists have studied human genetic diseases with what are known as “knock-out” mice. In this process, scientists “knock-out” or disrupt a gene of interest in mice so that they can observe the effect of the disease on its cells. Since mouse biology is different from human biology, these models present limitations.
Scientists have also tried to use induced pluripotent stem, or iPS, cells. In this process, a mature body cell, for instance from the skin, that carries a genetic disease is converted into a stem cell by adding a combination of genetic and chemical factors. The problem with these cells is that since they are diseased to begin with, they usually have other genetic defects that complicate the study of the disease in question.
The study was funded by the California Institute for Regenerative Medicine and utilized cells from the lab of Dr. Doug Melton at Harvard. Some of the Harvard lines have recently been approved for NIH funding so we should all stay tuned for more of these revolutionary breakthroughs with hESCs.
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