Research on Stem Cells Shows Promise in Lab Mice
By Doug Boyd
Research at East Carolina University has shown some stem cells can restore sensory function and reduce chronic pain in laboratory mice following spinal cord injury.
A team led by Dr. Alexander Murashov, associate professor of physiology at the Brody School of Medicine, injected mouse embryonic stem cells into mice with spinal cord injury. They found the mice that received the stem cell injections did not develop pain syndromes associated with spinal cord injury. Moreover, three days after the injection, the mice showed less sensitivity to pain compared to untreated mice.
Murashov spoke about the research Dec. 14 at a seminar sponsored by the Eastern Carolina Chapter for the Society of Neuroscience. He said the therapeutic effects of the stem cells might be due to a release of factors, or proteins, caused by the stem cells.
Not all stem cells are the same and not all have the same potential to turn into tissue. The most versatile are totipotent stem cells, which can become almost any tissue. Next are pluripotent cells that can give rise to most, but not all, of the tissues necessary for fetal development. Pluripotent cells undergo further specialization into multipotent cells that give rise to cells that have a particular function. For example, multipotent blood stem cells give rise to the red cells, white cells and platelets in the blood, but not other tissues.
“Our bone marrow stem cells don’t differentiate into nerve cells, for instance,” Murashov said. In addition, injured central nervous system tissue does not repair itself or regenerate as other tissue can, he said.
But embryonic stem cells do have this ability to generate different types of tissue. Theoretically, they could be used to generate particular nerve cells in vitro that could be transplanted into injured areas to restore function and reduce pain associated with spinal cord injury. An estimated 60 to 80 percent of people with spinal cord injury suffer from chronic pain, Murashov said, and no treatments exist for it.
Dr. Kori Brewer of the Department of Emergency Medicine also participated in the research. She has done previous research in spinal cord injury and pain. She said many growth factors and peptides, or molecules of amino acids, are known to alter an animal’s sensitivity to painful stimuli or protect against secondary cell death after injury. “It will be important to determine if the stem cells that are implanted into the injured spinal cord may be releasing some of these factors,” she said.
How the research may apply to humans with spinal cord injury will require further investigation. Murashov is looking for ways to treat spinal cord injury. Brewer is studying ways to reduce chronic pain associated with it. “If successful, we may then be able to suggest new therapeutic strategies that would be reasonable to study in humans suffering from this condition,” Brewer said.
Murashov is working to identify the genes responsible for the stem cells’ therapeutic effect. Such research is vital to understanding how and why stem cells behave the way they do.
“There is always a danger that stem cells may choose to develop into something we did not really want or expect, for example, a tumor,” Murashov said. “In other words, a lot of basic research still needs to be performed in order to use stem cells smartly and in the most efficient and safe way for the patient.”
Murashov’s stem cell research was supported in part by a two-year, $122,176 grant from the N.C. Biotechnology Center and was published last year in Molecular Medicine. He’s in the process of applying for National Institutes of Health funding to further the research. Other ECU researchers involved in the study are Elena Pak and Dr. Margarita Glazova of the Department of Physiology.
Information on Murashov’s research is at www.ecu.edu/physio/labakm. Information about research by members of the Eastern Carolina Chapter for the Society of Neuroscience is at www.ecu.edu/neurochapter/research-interest.cfm.