Neural Repair Institute: Advancing the Field of Neural Repair

Olfactory ensheathing cells (OECs) are unique glial cells found  only in the olfactory system; namely in the olfactory bulb inside the skull and in the olfactory epithelium of the roof of the nose.  These cells share phenotypic similarities to Schwann cells, astrocytes, and oligodendrocytes.  Olfactory ensheathing cells are known to aid axonal extension from the nasal mucosa, through the olfactory bulb PNS-CNS transition zone, to the central fibers in the olfactory glomeruli.  To achieve that, Olfactory ensheathing cells support axonal outgrowth by producing neurotrophic factors and cell adhesion molecules and, in addition, they migrate along with the regenerating axons.  Furthermore, Olfactory ensheathing cells provide a permissive environment for axonal extension through glial scars.

Olfactory ensheathing cells can be classified into two types according to the site of isolation; centrally derived and peripherally derived.  Centrally derived Olfactory ensheathing cells are harvested from the olfactory bulb whereas the peripherally derived Olfactory ensheathing cells are isolated from the olfactory mucosa.  The central cells pose a dilemma for autograft transplantation; invasive surgery is needed to harvest them from the olfactory bulb in addition to compromising the subject's smell sensation. 

One of the advantages of the use of OECs over Schwann cell transplants is that OECs can favorably coexist with astrocytes and may prevent an unfavorable response of astrocytes to injury including the buildup of inhibitory proteoglycans.