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Biodegradable Sponge Plus Olfactory Stem Cells Speed Recovery From Facial Palsy

DURHAM, N.C. NOVEMBER (2018) - A new study released today in STEM CELLS Translational Medicine demonstrates how a biodegradable hydrogel sponge seeded with olfactory stem cells (OSCs) greatly accelerated recovery from facial palsy in mice. The technique, developed by a team of researchers at Nagoya City University, Japan, shows potential for treating humans suffering from this condition — a frequent result of temporal bone fractures — as well as from other similar trauma or diseases such as Bell’s palsy or Ramsay Hunt syndrome, a painful byproduct of shingles.

In many ways facial nerve damage is similar to nerve damage in other areas of the body, which suggests that successful treatments developed for other neural environments could be applied to peripheral facial nerve paralysis, too. This includes OSCs. OSCs contain neural stem cells, plus they secrete growth factors and various cytokines that promote nerve regeneration. Clinical tests have already shown their promise in treating spinal cord injuries and other neural disorders. And because human OSCs are located in the olfactory epithelium, they can be easily harvested from the nasal cavity with limited risk, which makes them an especially attractive therapeutic candidate.

“In this study, we investigated the effect of OSC transplantation in a mouse model of facial nerve injury. The OSCs were transplanted with and without biodegradable hydrogel,” said Shinichi Esaki, M.D., Ph.D., the study’s lead investigator.

Past studies demonstrate that when stem cells are transplanted directly on an injury site, the hostile local environment can reduce their viability and functionality. To overcome that, the research team used MedGel SP19, a biodegradable sponge composed of gelatin hydrogel, as a scaffold for the OSCs.

“One technique used to avoid immediate host rejection of the transplanted cells is to inject the cells in a gelatin mixture,” explained Yuki Hamajima, M.D. “Gelatin is a biodegradable polymer that has been extensively utilized for pharmaceutical and medical purposes without any adverse effect. Various types of gelatin hydrogels have been transformed into sheets and used to accelerate tissue regeneration by holding and releasing various types of growth factors. In fact, gelatin hydrogel has also been shown to act as a scaffold for mesenchymal stem cells, allowing their homogeneous growth.

“However, the use of gelatin hydrogels to mediate OSC transplantation has not been previously evaluated, particularly for treatment of facial nerve palsy,” Dr. Hamajima added. “To our knowledge, this is the first time that transplantation of this particular OSC-gelatin hydrogel combination has been evaluated as a treatment for facial nerve palsy.”

The mice used in the study were randomly assigned to four groups of 10 each: one received the OSC/MedGel combination; one group received OSCs alone; one group received MedGel alone; and the mock group received no cells or MedGel. The mice were then monitored daily for two weeks following the procedure, looking for clinical signs of facial nerve paralysis.

“Facial movements were absent until day 3 and then increased gradually until full recovery at day 14, consistent with a previous study we had done using OSCs alone,” Yoshihisa Nakamura, M.D., Ph.D., reported. “During this time, we saw that OSCs impregnated in Medgel accelerated recovery on days 4 through 12, whereas OSCs alone only accelerated recovery on days 4 through 7. When used alone, Medgel did not accelerate recovery at all,” he added.

OSCs in Medgel also increased peripheral nerve function and the number of regenerated nerve fibers, the study revealed.

The recovery curves based on this data indicate that while OSCs accelerate recovery from facial nerve injury, the effect was observed for only a week. In contrast, the effect of OSCs was prolonged throughout the length of the study when combined with Medgel.

“We speculate that the Medgel helped retain the OSCs around the injury site and increased their survival and function, thus allowing them to secrete the cytokines and various factors necessary to mediate an enhanced and accelerated recovery response. Based on these results, we believe that clinical studies are now in order to determine the effects of this treatment,” Dr. Esaki concluded.

"These early pre-clinical results demonstrate a promising line of research that could someday accelerate facial nerve regeneration following injury and it will be fascinating to see how it progresses," said Anthony Atala, M.D., Editor-in-Chief of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine.


The full article, “Transplantation of olfactory stem cells with biodegradable hydrogel accelerates facial nerve regeneration after crush injury,” can be accessed at

About STEM CELLS Translational Medicine: STEM CELLS Translational Medicine (SCTM), published by AlphaMed Press, is a monthly peer-reviewed publication dedicated to significantly advancing the clinical utilization of stem cell molecular and cellular biology. By bridging stem cell research and clinical trials, SCTM will help move applications of these critical investigations closer to accepted best practices. SCTM is the official journal partner of Regenerative Medicine Foundation.

About AlphaMed Press: Established in 1983, AlphaMed Press with offices in Durham, NC, San Francisco, CA, and Belfast, Northern Ireland, publishes two other internationally renowned peer-reviewed journals: STEM CELLS® (, celebrating its 36th year, is the world's first journal devoted to this fast paced field of research. The Oncologist® (, also a monthly peer-reviewed publication, entering its 23rd year, is devoted to community and hospital-based oncologists and physicians entrusted with cancer patient care. All three journals are premier periodicals with globally recognized editorial boards dedicated to advancing knowledge and education in their focused disciplines.

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