Research focused on stem cell therapies has made significant strides over the past five to seven years. Stem cell research focuses on a search for cures and effective treatments for certain serious, incurable conditions and injuries like traumatic brain injury (TBI), spinal cord injury (SCI), as well as other types of nerve damage. A number of recent trials based around spinal cord injury research and traumatic brain injury research have been at the center of stem cell therapy progress.
Researchers are now looking to what they call a potential breakthrough in regenerative medicine. Scientists have developed a way to make stem cells by intentionally placing mature cells under stress.
Two new studies published during the last week of January depict a method of taking mature cells from mice and converting them to embryonic-like stem cells. These cells can then be coaxed into becoming any other kind of cell in the body.
New Approach may serve as an Alternative to Traditional, Controversial Stem Cell Research
The first of the two approaches is simply based on putting the cells in an acidic environment. Dr. Charles Vacanti, director of the laboratory for Tissue Engineering and Regenerative Medicine at Brigham & Women’s Hospital in Boston and senior author of one of the studies, said:
“I think the process we’ve described mimics Mother Nature. It’s a natural process that cells normally respond to.”
Both studies share a common new step in stem cell research for spinal cord injury and traumatic brain injury by way of a theoretical approach of inserting cells that can grow into whatever tissues or organs are needed, such as the brain or spinal cord. If you take an organ that’s functioning at 10% of normal and elevate it to 25% functionality, that could greatly reduce the likelihood of fatality resulting from a particular condition, such as cancer or a severe traumatic brain injury, according to Vacanti. Jeff Karp, associate professor of medicine at the Brigham & Women’s Hospital and principal faculty member at the Harvard Stem Cell Institute, commented on Vacanti’s approach:
“This method is truly the simplest, cheapest, fastest method ever achieved for reprogramming [cells].”
Researchers have experienced early stage successes in growing mini-brains from stem cells. However, prior to this new approach, the leading candidates for creating stem cells artificially were those derived from embryos in addition to stem cells from mature cells. These cells require the insertion of DNA to become reprogrammable.
Stem cells are created the natural way every time an egg that is fertilized begins to divide. During the first four to five days of cell division, so-called pluripotent stem cells develop. They then develop the ability to transform into any cell in the body. Removing stem cells from an embryo destroys it, which has been the source of some ethical and religious controversy over this method of research.
Researchers used Stressors to Successfully Facilitate Cell Changes
The researchers’ second new approach involves a method of producing embryonic-like stem cells by taking a skin cell (potentially from a spinal cord or traumatic brain injury patient) and adding small pieces of foreign DNA to reprogram the skin cell. This method enables the cell to behave like an embryo and produce pluripotent cells, too. However, these cells are used primarily for research purposes because researchers do not want to introduce cells with extra DNA into living human subjects.
The new method does not require the destruction of embryos or the insertion of new genetic material into cells, Vacanti explained of the team’s revolutionary approach.
It also successfully addresses the obstacle of rejection by the body. The human body could reject stem cells harvested from other people, but this method uses an individual’s own mature cells. Haruko Obokata of the Riken Center for Developmental Biology in Japan said:
“It was really surprising to see that such a remarkable transformation could be triggered simply by stimuli from outside of the cell.”
The process is called STAP, which stands for “stimulus-triggered acquisition of pluripotency.” Karp estimates that the method is five to 10 times faster than other means of reprogramming cells. Scientists first used laboratory mice to study the STAP cell phenomenon. They genetically altered the mice donating stem cells to “label” those cells with the color green by modifying the donor cells to appear green under a microscope when subjected to a particular wavelength of light.
Next, researchers exposed blood cells from the genetically altered donor mice to an acidic environment. Within a few days, they observed that these cells changed into the embryonic-like state and grew in spherical clusters. Scientists then place the cell clusters into a mouse embryo that had not been genetically modified. Unexpectedly, the team also found that the implanted clusters could form tissues in all of the organs that the researchers tested. The scientists were able to follow the donor cells throughout each stage due to greenish qualities they retained throughout the transformations.
More Research Necessary to address Variables, but Researchers are Optimistic over Current Progress
Besides modifying acidity, researchers also stressed the cells by lowering the oxygen saturation and disrupting the cell membrane. However, the group discovered that increasing acidity proved to be among the most effective methods of turning mouse blood cells into STAP cells, with a few marginal (but acceptable) caveats.
For now, the STAP cell procedure has only been demonstrated in cells from young mice. The effectiveness in humans, and the risks, are still unknown. Researchers have not yet shown how STAP embryonic-like stem cells compare with bona fide embryonic stem cells or induced pluripotent stem cells, according to Karp.
Also, although the study was “rigorous” and “well-controlled,” it did not demonstrate exactly why the stress on the cells caused them to become STAP cells, Karp added. As with everything in science, more research is required to confirm the findings and learn more about the implications. Vacanti hopes the process could get tested clinically in humans within three years. He noted that induced pluripotent stem cells are already being explored in Japan in humans and the same “platforms” might potentially serve as a basis for STAP cells.
Karp concluded his summary of the team’s work by noting how new reprogramming approaches to stem cells seem to be emerging rapidly and on a constant basis and that this one in particular “looks incredibly promising”.
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