StemCells Inc. (STEM) shares jumped some 10% Thursday after the company reported new preclinical data showing its proprietary human neural stem cells restore lost motor function in mice long after their spinal cord injuries.
The study, which was led by Dr. Aileen Anderson of the Sue and Bill Gross Stem Cell Research Center at the University of California, Irvine, was published Wednesday in the Public Library of Science peer-reviewed journal PLoS ONE.
Stem cells are unspecialized cells that can develop into many different cell types in the body. In the study, the company's human neural stem cells (hCNS-SCns) were transplanted into mice 30 days after spinal cord injuries that paralyzed their hind limbs. The results revealed that that the cells migrated through the spine, divided and became functional. The transplanted mice demonstrated a significant and persistent recovery of walking ability when compared to control groups.
What differentiates this study from similar other studies is the time line. The human neural stem cells were injected at the end of the trauma phase, in a chronic spinal cord injury setting -- after the inflammation has stabilized -- and the mice still showed improvement. Other similar studies have concentrated on the early phases after the injury. For example, in its upcoming human trial, rival Geron (GERN) intends to recruit patients and inject them with its drug seven to 14 days after their injuries.
"[P]ublished research to date has generally focused on the acute and sub-acute phases," Anderson said in a statement. "This latest study builds on the extensive work we had previously published in the sub-acute phase of injury, and offers additional hope to those who are paralyzed or have impaired motor function."
Potential to Heal Older Injuries
Most human spinal cord injuries are contusions -- bruises -- rather than severing of the spinal cord. Such injuries cause severe inflammation that is particularly damaging to the oligodendrocytes (special nervous system cells) in the spinal cord, resulting in the paralysis of those patients. Studies of other drugs that took place a few months after these injuries were sustained were ineffective due to scarring that occurred in the injured region as part of the inflammatory response to the injury.
In humans, the chronic phase typically sets in several weeks or months after an injury, and the StemCells study suggests the prospect of treating a much broader population of injured patients.
"These exciting results demonstrate an expanded window of opportunity for human neural stem cell intervention in spinal cord injury," stated Dr. Stephen Huhn, head of the CNS Program at StemCells. "1.3 million individuals in the U.S. are living with chronic spinal cord injury, and this latest study provides additional evidence that the use of our human neural stem cells may be a viable treatment approach for them."
StemCells plans to begin human trials in 2011.
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