Transplanted olfactory ensheathing cells incorporated into the optic nerve head ensheathe retinal ganglion cell axons: Possible relevance to glaucoma

A mixture of olfactory ensheathing cells and fibroblasts cultured from the adult rat olfactory mucosa was transplanted through a scleral incision into the retina. A major stream of transplanted cells migrated through the stratum opticum and penetrated for up to about 0.5 mm into the optic nerve head. This stream of transplanted cells consisted of a mixture of bipolar olfactory ensheathing cells with long processes which give rise to a non-myelinating ensheathment of single retinal ganglion cell axons, and olfactory nerve fibroblasts embedded in a dense fibronectin-positive extracellular matrix. A second stream of ovoid olfactory ensheathing cells with tufted processes and unaccompanied by fibroblasts or matrix migrate into the internal plexiform layer. The incorporation of olfactory ensheathing cells in the optic nerve head may suggest future possibilities for protection of the axons in this vulnerable region from mechanical damage, as in the raised intraocular pressure of glaucoma.