TOKYO >> A Saga University research team is aiming for a summer start on a clinical study involving the transplant of blood vessels made with a 3-D bioprinter into patients receiving hemodialysis.

The team, led by Saga organ regeneration researcher Koichi Nakayama, has submitted an application for the study to a committee designated by the central government.

Transplanting body tissues produced by a 3-D bioprinter is without precedent.

In conventional regenerative medicine, transplantation involves individual cells and sheet-shaped body tissue. The goal is for 3-D bioprinters to produce tissues and organs with more complicated shapes, advancing the field of regenerative medicine.

In the study, a 3-D bioprinter developed by Nakayama, Tokyo-based medical equipment start-up Cyfuse Biomedical K.K. and others will be used.

Researchers will cultivate skin cells to produce cell chunks that will become the raw material for the generated tissue.

The researchers will then thread the cell chunks onto thin, long needles lined in accordance with 3-D data of blood vessels.

The cells will stick together within several days, forming blood vessels about 2 inches long and 1/4 inch in diameter.

Researchers will transplant the blood vessels into three to five patients receiving hemodialysis, aiming to replace shunts that remove blood from the body. When shunts are left in patients’ arms for an extended period, they become clogged, preventing blood from flowing smoothly. The goal is to improve the flow with 3-D printed blood vessels.

The team will examine the safety and effectiveness of the method for six months.

“Blood vessels made from patients’ own cells will not be rejected and are less likely to cause infectious diseases compared to shunts,” said Nakayama. “They can also repair themselves if holes from injections are made.”

The cells are scheduled to be processed in a facility in Gamagori, Aichi Prefecture. The study plan is being screened by a government-designated committee on regenerative medicine. The clinical study is supported by the Japan Agency for Medical Research and Development.