CELLS FROM THE NOSE

The cells that are involved in our sense of smell (olfaction) possess characteristics that could also be very useful for repair of the damaged spinal cord. Olfactory neurons (nerve cells) are unique in that they are the only known neurons to replace themselves throughout adult life. The nerve fibres of these cells are surrounded by cells called olfactory ensheathing cells (OECs). When new neurons are born, the nerve fibres are guided from the nasal tissue up through holes in the bone in the roof of the nasal cavity and into the olfactory bulb (part of the brain) by the OECs.  Although not technically stem cells, OECs have considerable regenerative potential and have been the focus of much attention in the spinal cord injury research community.

When OECs are transplanted into the injured spinal cord of animals they promote axonal (nerve fiber) regeneration and some functional recovery. Exactly how this occurs is theoretical but could be due to a number of different things happening within the injury site.  These include, OECs guiding the growth of nerve fibres or wrapping around (and insulating) intact but non-functional nerve fibres, thus making them functional again; OECs secreting growth factors, or generating a matrix that cells can attach to and grow along, thus enabling re-growth and repair.

The olfactory (nasal) tissue has many specialised cells, including a type of stem cell. These stem cells are thought to be the origin of the new neurons (nerve cells) and also possibly the origin of replacement OECs and other support cells with the olfactory tissues.

Some researchers believe that the transplantation of more than one cell type will be required in order to induce sufficient repair and produce functional recovery.

One such researcher is Dr Carlos Lima of Lisbon Portugal. Dr Lima has developed a method of transplanting olfactory mucosa (nasal lining), obtained from high in nasal passages (roof of the nose), into the site of damage within the spinal cord. Dr Lima and his surgical team, harvest OECs and stem cells from the olfactory mucosa and transplant them into the injured spinal cord in a single operation.  This procedure has been performed on 70 participants, with many of the latest cases including people from the United States.

We have also been granted Ethics approval to obtain and study the nasal tissue from SCI volunteers and patients having nasal surgery. The aim of this study is to study the OECs and establish a cell culture protocol to enhance the numbers.