June 5, 2002
Intravenous injections of cells from human umbilical cord blood improved the neurological and motor function of rats recovering from severe traumatic brain injury, researchers at Henry Ford Health Sciences Center (HFHSC), Detroit, and the University of South Florida (USF), Tampa, found.
The study appears in tomorrow's issue of the journal Cell Transplantation, a special issue that focuses on emerging approaches in neural transplantation and brain repair. It is one of several articles exploring the therapeutic potential of human umbilical cord blood (HUCB) cells as an alternative to embryonic stem cells.
While studies of cellular therapies continue to grow in importance, the emphasis has been on neurological diseases like Parkinson's disease and stroke, and, more recently, on spinal cord injury.
"This study is the first to suggest that human umbilical cord blood may be a novel way to treat traumautic brain injury, a significant cause of death and disability for adolescents and young adults," said report co-author Paul R. Sanberg, PhD, DSc, director of the USF Center for Aging and Brain Repair.
"The results certainly raise some interesting questions about the mechanisms of recovery," said co-author Juan Sanchez-Ramos, PhD, MD, Helen Ellis professor of neurology and director of stem cell research at the USF Center for Aging and Brain Repair. "It appears that the growth factors and cytokines from cord blood help promote the brain's self-generated repair of damaged tissue."
"These findings were consistent with the therapeutic benefit we obtained using cord blood to treat stroke in rats," said Michael Chopp, PhD, a neuroscientist at HFHSC and lead author of the report. This earlier study was published last November in the journal Stroke.
"Cord blood is readily available, noncontroversial and produces therapeutic benefit by stimulating endogenous restorative responses in the injured brain," Dr. Chopp said.
HUCB cells were injected intravenously into the tail veins of rats 24 hours after traumatic brain injury. At both 14 and 28 days after treatment, the rats receiving cell transfusions showed greater improvements in movement, balance and reflex responses than brain-injured rats receiving a placebo or no treatment.
The cord blood cells migrated to the region of the brain injury. A small
portion took on the characteristics of immature neurons and other brain
cells known as astrocytes. Some others integrated into the brain's blood
vessels. Only a limited number of HUCB cells drawn to the area of brain
injury actually expressed proteins typical of those in early neural cells.
Umbilical cord blood contains a small percentage of primitive stem cells — totally undifferentiated cells with the potential to develop into any one of the specialized tissues in the body, including blood, skin, muscle or nerve cells.
"It is unlikely that hastened recovery from the trauma could be solely attributed to such small numbers of stem cells transforming into neural cells," Dr. Sanchez-Ramos said.
Some HUCB cells that became part of brain tissue surrounding the injury expressed characteristics of endothelial cells lining the brain blood vessels. This suggests the injected cells may help regenerate injured vessels, Dr. Sanchez-Ramos said.
A second study in Cell Transplantation , by USF neuroscientist Tanja Zigova, PhD, reported that some undifferentiated HUCB cells transplanted into the developing brains of neonatal rats begin to appear like nerve cells and express certain proteins found only in neurons and glial cells. The findings suggest that at least some of the transplanted HUCB cells took on the characteristics of neural cells in response to cues from the young brain.
Researchers at the USF Center for Aging and Brain Repair are continuing studies to identify and expand the stem-cell portion of HUBC and to define how cord blood cells promote brain recovery.
The HUCB studies were suppported by Saneron CCEL Therapeutics Inc., an affiliate of Cryo-Cell International Inc., a company that collects and stores umbilical cord blood. A State of Florida High Tech Corridor grant also funded the research.
Other researchers working on the two studies were Dunyue Lu, MD; Asim Mahmood, MD; and Lei Wang, MD, all of HFHSC; and Shijie Song, MD; Alison Willing, PhD; Jennifer Hudson; Mary Newman; and Samuel Saporta, PhD, all from USF.