Kyoto University said Friday it has conducted the world's first transplant of induced pluripotent stem cells to treat Parkinson's disease.

Nerve cells created from the artificially derived stem cells were transplanted into the brain of a patient in his 50s in October in a treatment that researchers hope to develop into a method widely used internationally and covered by health insurance.

"By also cooperating with companies, we want to develop a mass production system that enables us to deliver nerve cells derived from iPS cells to all over the world," Jun Takahashi, a professor at the Japanese university's Center for iPS Cell Research and Application who led the research team, told a press conference.

(Jun Takahashi)

Parkinson's disease reduces dopamine-producing neurons in the brain and results in tremors in the hands and feet, and stiffness in the body. While there are treatments to relieve the symptoms, there is currently no cure for the disease.

In Japan, an estimated 160,000 people suffer from the progressive neurological disorder. Many patients develop symptoms in their 50s or older, and the number of patients is rising due to the aging of society.

The clinical test was carried out by the research center and Kyoto University Hospital, with doctors playing leading roles in verifying the transplant's safety and effectiveness.

Shinya Yamanaka, who heads the center, won the Nobel Prize in physiology or medicine in 2012 for discovering iPS cells, which can grow into any type of body tissue and are seen as a promising tool for regenerative medicine and drug development.

According to the treatment plan, the nerve cells transplanted into the brain were created using iPS cells derived from people who had types of immunity that made them less prone to transplant rejections.

The nerve cells are expected to supplement dopamine-emitting neurons.

During treatment to be monitored for two years, immune suppressor drugs will be injected to reduce the possibility of rejections.

The first transplant performed last month is mainly aimed at verifying the safety of such a transplant by checking whether any tumors develop in the brain. So far, no hemorrhages within the brain or other harmful symptoms have been found, according to the university.

At the press conference at the hospital, Takayuki Kikuchi, a surgeon, elaborated on the process of the three-hour operation he performed.

"We made a hole in the frontal part of the head's left side and transplanted some 2.4 million cells," he said, adding the patient smiled with relief after the operation.

The pioneering study will be conducted on seven patients in their 50s and 60s, who fulfilled the criteria of having received drug treatments without effective results and having suffered from Parkinson's disease for more than five years.

Hisao Hiramine, a 70-year-old who suffers from the disease and chairs a Tokyo association of patients and their families, said, "Having heard the news of the first trial, I feel the research is steadily moving forward step by step. We are all looking forward to hearing a positive outcome."

Asked about his eventual goal, Kyoto University's Takahashi said, "The best scenario is to see patients improve to the extent they do not have to take any medicine."

"For surgeons, the result is all that matters," he said.

Outside Japan, nerve cells from aborted fetuses have been transplanted into patients' brains in clinical research since the 1980s. Although the method proved effective to a certain extent, it entailed ethical problems and side effects in which patients' bodies moved unintentionally.

The iPS cells involved in this study were produced and stored by the university, which said they are of high quality for clinical use and could also be prepared in a large volume.

The application of iPS cells to health treatment follows the world's first surgery by the Japanese government-backed Riken institute to transplant retina cells grown from stem cells to treat patients suffering from serious eye problems.

Among other clinical trials on regenerative medicine, Osaka University is planning to transplant a heart muscle cell sheet derived from iPS cells into the hearts of patients suffering from serious heart failure.

Another research team of Kyoto University is expected to begin a blood transfusion test using platelets created from the stem cells to treat patients with aplastic anemia.