Photo/IllutrationPatients undergoing rehabilitation at a hospital (Asahi Shimbun file photo)

Treatment of traumatic brain injuries may soon be a few injections away.

A bio-venture company has confirmed improved arm and leg function in clinical trials of patients who underwent stem cell shots to repair damaged brain tissue.

Tokyo-based SanBio Co. announced the findings at a meeting of the American Association of Neurological Surgeons held in the United States in April.

The company plans to seek health ministry approval by January 2020 to manufacture and commercialize the stem cell-based product for medical treatments.

Mesenchymal stem cells that can be transformed into bones and blood vessels are extracted from bone marrow aspirates collected from healthy people and are cultivated in large quantities.

The stem cells are then made into a product for use in regenerative medicine.

The product is transplanted close to damaged areas in patients through injections, and the stem cells help regenerate nerve cells in the brain, resulting in improved functions of arms and legs.

The clinical trial covered 61 people in Japan and the United States with traumatic brain injuries in the chronic stage.

The stem cell product was injected into 46 of them, with the other 15 not receiving the transplantation.

As a result, arm and leg functions improved 8.7 points on the motional function assessment index among the 46 subjects. While an improvement of 2.4 points was also seen among the remaining 15 people, SanBio said, "We were able to confirm a statistically significant difference."

All 61 people experienced headaches during the clinical trial, but 90 percent of such cases are believed to have no connection to the product. The company concluded the headaches did not represent a safety concern.

While the exact number of patients in Japan with damaged nerve tissue in the brain is unknown, the firm estimates it to be 40,000. There are currently no effective treatment methods other than rehabilitation.

The health ministry in April designated the stem cell product as a medicine subject to the “priority screening designation system” for new medicine.

"It is believed that the product has anti-inflammatory effects and can be used to regenerate blood vessels," said Akifumi Matsuyama, a professor of regenerative medicine at Fujita Health University. "It has the potential to serve as an effective treatment method."

The product was also used in a clinical trial for patients of brain infarction in the chronic stage. However, the extent of its effectiveness was not confirmed.