Grafting the olfactory epithelium to the olfactory bulb

Impaired olfactory function leads to a decrease in the quality of life for many patients. Surgical treatment options are limited, especially for those suffering from hyposmia or anosmia after posttraumatic injury to the olfactory nerves. Stem cells located in the olfactory epithelium (OE) have the capacity to grow new neurons, making the OE an ideal candidate for restorative tissue grafting. This study was performed to determine if strips of OE survive transplantation directly to the olfactory bulb (OB).

Transgenic mice, expressing a green fluorescent protein (GFP), were used to obtain the donor graft tissue. Strips of OE from GFP donor mice were transplanted directly to sites in the OB and cerebral cortex (CC; control sites) of wild-type mice. Graft survival rates at 30 days were determined for transplant sites in the OB and CC.

Strips of OE from transgenic mice survived transplantation to the OB and continued to express the GFP marker protein. The 30-day survival rate in the OB (83%, 5 of 6 grafts) was the same as in the CC (10 of 12 grafts). The morphology of the graft revealed characteristics found in normal OE.

We showed that strips of OE can be successfully grafted to both the OB and CC. Grafts of the OE, if strategically positioned on the ventral surface of the bulb and given access to the nasal cavity, could provide the basis for new surgical treatments to restore olfactory function.