Enrollment has begun for the first clinical trial to test a therapy developed from human embryonic stem cells.

The trial’s primary aim is to assess the safety of Geron Corp.’s experimental oligodendrocyte progenitor cells, which have been in development for about a decade. They were derived from some of the earliest human embryonic stem cells ever created.

Oligodendrocytes are cells that insulate nerve fibers with myelin, allowing electrical signals to be transmitted to and from the brain. These cells are damaged in patients with spinal cord injuries, resulting in paralysis. Making replacement cells out of embryonic stem cells is a long-held goal for many scientists, including neuroscientist Hans Keirstead, whose research team helped develop the treatment at UC Irvine.

In rats, the experimental cells – known as GRNOPC1 – helped restore the essential myelin sheath around nerve cells in the spinal cord. Treated animals regained their ability to walk and run, though they did so with a noticeable limp.

Though researchers will mainly be focused on whether the stem cells are safe to use in people, they will also look for signs that the cells can restore at least some neuromuscular control to patients’ legs and torsos.

Geron scientists believe the therapy has the best chance of working in patients who are newly paralyzed. For the clinical trial, researchers are looking for patients with thoracic spinal cord injuries that are 7 to 14 days old.

The trial will be small, with a maximum of 10 patients. The first volunteers will be treated by doctors from Northwestern University’s Feinberg School of Medicine and the Rehabilitation Institute of Chicago. As many as six additional sites around the country will be added to the trial.

More information about the trial is available on Geron’s website.

-- Karen Kaplan / Los Angeles Times