Can spinal cord injuries be reversed?

Regeneration: Growing new nerve connections
Successful repair of spinal cord injuries will depend, in part, on the regrowth and replacement of damaged connections between spinal nerve cells. In 2006, Novartis launched in Europe the first clinical trial of a purely regenerative drug in spinal cord patients.

In the initial feasibility phase, 15 patients were given this antibody drug, known as anti-Nogo, and now a larger trial to investigate safety and effectiveness is under way. This drug works by blocking Nogo (so called because it tells nerve connections not to grow), an inhibitory protein that stops spinal cells from sprouting new connections. In animal studies, primates whose spinal cords were partially severed regained 80 per cent of their hand movements after being treated with anti-Nogo antibodies.

Clinical trials are expected to begin at Toronto Western Hospital and other spinal injury centres in Canada and the U.S. early in 2008.

Restoration: Cell transplants offer great promise
Cell transplants, which we hear a lot about, are being looked at as part of a long-term strategy for repairing and possibly curing spinal cord injuries. The concept is simple: replace some or all of the cells that have been destroyed as a result of a spinal cord injury to help patients regain mobility.

“The promise is that you might have regeneration of damaged nerve fibres. The big challenge is to get the right cells into the right place and working,” says Dr. Armin Curt, a neurologist and chair of SCI Rehabilitation Research at UBC.

Major progress has been made in the past decade in testing transplants of different types of cells in animal models of spinal cord injury. Some of the most promising types of cells being tested include embryonic and adult stem cells, Schwann cells (from peripheral nerves) and olfactory glial cells (from the nasal lining). With Schwann and olfactory glial cells, the strategy is to transplant them and harness their regenerative properties to repair the injured cord.

With stem cells, the hope is that embryonic or adult stem cells can be coaxed into becoming functioning cells in the damaged area of the spinal cord. In a 2006 experiment, for example, Fehlings of Toronto Western Hospital transplanted stem cells from the brains of adult mice into rats whose spines had been crushed. The stem cells restored myelin (an insulating layer around nerve fibres that transmits signals from the brain) in the damaged area and the rats gained more mobility. Fehlings predicts that stem cell therapies for spinal cord injury could be safely tested in human patients within five to 10 years.

Cell transplants offer exciting potential but are controversial because of unregulated procedures now being performed on spinal cord patients in China, Russia, Portugal and other countries.

A 2006 study by Curt and two other leading neurologists (published in Neurorehabilitation and Neural Repair) assessed seven patients who received olfactory ensheathing cell transplants in China. After surgery, three patients developed meningitis and none of the seven showed measurable improvements in their condition. More research is needed to show safety and effectiveness, says Curt, before cell transplants are ready for testing in patients.

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