Neurotrophic Factors Aid Laryngeal Reinnervation: Rat study highlights potential new technique for nerve injury

Results

On videolaryngoscopy after two months, researchers saw only some weak adduction in one CNTF animal. But, on laryngeal electromyography, they saw heightened recruitment scores in the TA muscles in the groups that had received CNTF. And they saw reduced scores in the PCA muscles in those who had received vincristine, as they had hoped.

“At two months, on immunohistochemistry, nearly all of the animals at this point were demonstrating evidence of partial reinnervation of the adductor complex,” Dr. Halum said. At four months, there was less of a difference on laryngeal electromyography, but there was a different story in the immunohistochemistry evaluation; the team found that eight of the stem-cell treated animals had over 66 percent motor endplates with nerve contact.

Applications

The findings could be a launching pad for further use of neurotrophic factor with stem cells, Dr. Halum said. “The study really just serves as a proof of concept,” she said. “It proves that we can have efficient selective delivery of neurotrophic factor with our stem cell vectors. We found a wide variety of spontaneous reinnervation patterns that were enhanced with the stem cell-treated animals.”

Dr. Halum said that in the future, clinicians may be able to use these stem cell techniques to adjust vocal cord position. “In fact, as new investigators are coming out with ways of developing a tissue-engineered larynx, neurotrophic factor-secreting stem cells could readily be incorporated to guide and direct reinnervation,” she said.

Gayle Woodson, MD, professor and chair of otolaryngology-head and neck surgery at Southern Illinois University School of Medicine in Springfield, who has conducted research on reinnervation, said the use of stem cell vectors might help refine reinnervation efforts. “You can always get the nerve to go back to the muscle, but it might not go back to the right muscle,” she said. “You don’t get good movement. Sometimes, the vocal cord is just sitting still or sometimes going in the wrong direction.”

Most groups looking at using neurotrophics, she said, have not considered stem cells. She said she is looking forward to more research being done in this area. “We’re not there yet,” she said. “It’s a lot of the basic science that has to be worked out.”

Randal Paniello, MD, associate professor of otolaryngology-head and neck surgery at Washington University in St. Louis, Mo., said “the work is very exciting and may very well lead to improved outcomes in the future for patients with vocal cord paralysis.”