New approach points towards effective stem cell therapies for spinal cord injury

Initial experiments suggest a possible new approach to stem cell therapy for spinal cord injuries—using biocompatible "channels" made of chitosan to guide regeneration of new spinal cord tissue, reports the December issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, and pharmacy.

The use of chitosan channels "enhanced the survival of transplanted neural stem/progenitor cells" in rats, according to the study by Dr. Gokhan Bozkurt and colleagues of University of Toronto.

New Approach May Point Toward Effective Stem Cell Therapies for Spinal Cord Injury
The researchers compared two approaches to stem cell therapy in rats with induced spinal cord injuries. In one group, specialized neural stem cells were injected directly into the area of the spinal cord injury. In the other group, the stem cells were placed into tiny tubes, or "channels," made out of chitosan.

Chitosan is a natural substance that is a major component of "crustacean exoskeletons"—for example, shrimp or lobster shells. The chitosan channels were created to provide a "biocompatible scaffolding" to promote and guide the growth of transplanted neural stem cells.

Several weeks after stem cell transplantation, rats receiving chitosan channels showed "less tissue loss" than those receiving stem cells alone. The percentage of surviving stem cells was very low in both groups, but significantly higher when they were delivered in chitosan channels: 1.1 percent, compared to 0.18 percent with stem cell injection alone.

The increase in stem cell survival with chitosan channels wasn't enough to make a significant difference in recovery of function several weeks after spinal cord injury. In both groups, the surviving stem cells showed evidence of differentiation into specific types of spinal cord cells.

Stem cells have promise for the development of new treatments for spinal cord injury. Previous studies have shown that specialized neural stem cells can be induced to differentiate into different types of spinal nerve cells. However, there are important obstacles to developing stem cell techniques capable of bridging the injured area of the spinal cord and restoring function.

Although the new study is only a first step, the use of chitosan channels could one day lead to effective new approaches to using adult stem cells for spinal cord injuries. The results show that the use of "bioengineered, biodegradable, biocompatible, and non-toxic" chitosan channels can improve the survival of stem cells used to treat spinal cord injuries in rats.

Despite some encouraging results, the rate of stem cell survival was still very low and the technique did not lead to significant improvements in functional recovery. The authors are working on modifications to the chitosan channels in the hope of further enhancing the survival of stem cells and improving their ability to bridge the injured area.