Stem cells have several unique properties that separate them from other cells.

They can proliferate so that they are capable of replenishing themselves for long periods of time by dividing, and they are unspecialized cells that can differentiate into specialized cells such as nerve or heart cells. In addition to treating cancers such as leukemia, stem cells are used to treat other diseases such as Parkinson's, stroke, Alzheimer's, retinal diseases and spinal cord injuries.

Just this month, researchers showed that stem cell therapy has been successful in treating sight loss from macular degenerations. Nine patients with Stargardt's mascular dystrophy and nine with dry atrophic age-related macular degeneration had injections of 50,000 to 150,000 retinal pigment cells behind the retina of their worst-affected eye.

The pigment cells were created in the lab by treating human embryonic stem cells (hESCs) with chemicals that make them transform into retinal cells. Results from this study suggested the safety and promise of hESCs to alter progressive vision loss in people with degenerative diseases. The study also marked an exciting step toward using hESC-derived stem cells as a safe source of cells for the treatment of various medical disorders requiring tissue repair or replacement.

Spinal cord injury (SCI) is one such target of regenerative cell therapy.

SCI is an important contributing factor to morbidity and mortality in the United States, currently affecting about 200,000 people. In Britain, a person suffers a serious spinal injury once every eight minutes.

Such was the case with Darek Fidyka, who was paralyzed from the neck down after a knife attack that sliced cleanly through his spine and left him with a 1 percent chance of even the slightest recovery. An Anglo-Polish team knitted Darek's spinal cord back together, restoring sensation and muscle control to his legs. The technique was developed by researchers at the University College London and put into practice by surgeons in the Polish city of Wroclaw.

The team used specialist human cells, which repair damage to nasal nerves, enabling spinal nerve fibers to regrow and bridge a severed cord. Professor Geoff Raisman, the head of UCL's Institute of Neurology, and his team conducted the ground-breaking research, contending that the olfactory bulb — the part of the brain that processes smell — could facilitate the connection of regenerated nerves elsewhere in the body.

From this discovery, the team of surgeons implanted harvested olfactory ensheathing cells (OECs) into an 8 millimeter gap in Fidyka's spinal cord. The OEC implants on the two stumps of Fidyka's spinal cord slowly restored the feeling and sensation to his legs. Ten months later, Fidyka was able to walk with the help of braces and a walking frame. He is now able to drive.

Although both medical teams underline that the new technique has only been used on a single patient and needs to be repeated in a larger group, regenerative medicine holds great hope and promise for people suffering from untreatable conditions.

The case of Fidyka could possibly be the first time a patient has been able to regenerate severed long spinal nerve fibers across an injury and resume movement and feeling, which may just open the door to a treatment of SCI that will get people out of wheelchairs.