By Alka Agrawal, PhD
SAN DIEGO, Apr 19 (Reuters Health) - Neural stem cells seeded on a biodegradable scaffold promote spinal cord regeneration in the severed spinal cords of adult rats, according to a presentation here at this week's Experimental Biology 2000 meeting.
Dr. Lawrence Bonassar, of the University of Massachusetts Medical School, Worcester, isolated neural progenitor cells from adult rats carrying the gene for a fluorescent protein, mixed them with a gel, and seeded the mixture on a biodegradable scaffold. The researchers surgically removed 2 to 3 mm of spinal cord from genetically identical rats and implanted the scaffold plus cells into the gap.
After 2 months, only rats implanted with cells and scaffold had significant development of spinal tissue, Dr. Bonassar said in an interview with Reuters Health. In contrast, animals that had a sham operation, or received either cells or scaffold alone, had only bony spurs and scar tissue. Dr. Bonassar noted that some animals have been followed for as long as 18 months.
The regenerated spinal cord was positive for the fluorescent protein, confirming that it came from the implanted cells, and it was also positive for several neural-specific markers.
Significant sensory and motor recovery occurred within a month in eight of nine rats that received both cells and scaffold, while all other animals remained paralyzed. Several animals were essentially walking, Dr. Bonassar said. The level of function was similar to that in animals that had not undergone an operation.
Dr. Bonassar noted that many groups have grafted neural stem cells alone
into the central nervous system, but no one has used a carrier like a polymer
matrix. "It can serve both an active and a passive role," he said. "It
serves to keep the cells localized to where you want them. Also, if you
play around with the composition of the polymer you can essentially send
signals through the polymer," he said, through the use of growth factors
or adhesion molecules.