A team of researchers in Japan says two of four patients who received transplantation of special stem cells showed motor function recovery in a clinical study to repair spinal cord injuries.

The researchers from Keio University and other institutions said it was the first case in the world in which a treatment using cells derived from induced pluripotent stem cells, or iPSCs, helped improve symptoms of patients with spinal cord injuries.

In the clinical study, the team transplanted 2 million iPSC-derived cells into the four patients, who were unable to move and had lost sensation due to spinal cord injuries. The degree of motor function recovery was examined one year later.

One elderly man, who was injured in an accident, reportedly became able to stand without support and began practicing to walk. The patient's motor function score improved from the lowest rank of A to the higher level of D, on a scale of A to E.

Another patient's motor function score reportedly also went up two ranks to C. The patient is still unable to stand but became able to eat alone. The remaining two patients showed no motor functional recovery.

The researchers said the four patients did not develop any serious health problems.

Patients with spinal cord injuries sometimes see their motor function improve through rehabilitation. But only about 10 percent of them see a recovery of two levels from the lowest rank of A.

They claim it is the first successful case of patients with spinal cord injury recovering motor function using iPSC treatments.

There are about 5,000 new cases of spinal cord injuries every year in Japan. The researchers said they plan to conduct a clinical trial to obtain government approval for the treatment.