Transplantation of nasal olfactory tissue promotes partial recovery in paraplegic adult rats

Recent reports have highlighted the potential therapeutic role of olfactory ensheathing cells for repair of spinal cord injuries. Previously ensheathi ng cells collected from the olfactory bulbs within the skull were used. In humans a source of these cells for autologous therapy lies in the nasal muc osa where they accompany the axons of the olfactory neurons. The aim of the present study was to test the therapeutic potential of nasal olfactory ens heathing cells for spinal cord repair. Olfactory ensheathing cells cultured from the olfactory lamina propria or pieces of lamina propria from the olf actory mucosa were transplanted into the transected spinal cord. Three to t en weeks later these animals partially recovered movement of their hind lim bs and joints which was abolished by a second spinal cord transection. Cont rol rats, receiving collagen matrix, respiratory lamina propria or culture medium, did not recover hind limb movement. Recovery of movement was associ ated with recovery of spinal reflex circuitry, assessed using the rate-sens itive depression of the H-reflex from an interosseous muscle. Histological analysis of spinal cords grafted with olfactory tissue demonstrated nerve f ibres passing through the transection site, serotonin-positive fibres in th e spinal cord distal to the transection site, and retrograde labelling of b rainstem raphe and gigantocellularis neurons from injections into the dista l cord, indicating regeneration of descending pathways. Thus, olfactory lam ina propria transplantation promoted partial restoration of function after relatively short recovery periods. This study is particularly significance because it suggests an accessible source of tissue for autologous grafting in human paraplegia. (C) 2001 Elsevier Science B.V. All rights reserved.