A team of researchers from the University of Tokyo has successfully managed to create a bundle of motor nerves using human induced pluripotent stem (iPS) cells, it has been learned.
The discovery is promising because the motor nerves formed by the team are similar to those inside the human body -- something that could lead to the development of medicines capable of treating intractable diseases such as amyotrophic lateral sclerosis (ALS), which is caused by motor nerve abnormalities.
Motor nerves are cells that carry electric signals from the brain, and then travel along a path known as an "axon" in order to enable muscle movement. Although it is possible to create motor nerve axons using human iPS cells, it had not been possible to form a bundle of axons that is similar to that inside the body until now.
Specifically, the team, which is from the University of Tokyo's Institute of Industrial Science, generated spheroids after collecting approximately 10,000 motor nerves made from human iPS cells. After cultivating the spheroids, it was found that several thousand axons had emerged and stuck to the spheroids -- creating a bundle with a thickness of about 0.05 to 0.1 millimeters within 25 days.
Upon examining the bundle of motor nerve axons, the team confirmed that electric signals could be transmitted along the axons in a similar way to that in the body. It was also observed that the function of the axons worsened upon being immersed in an aqueous solution, which is easy to oxidize.
ALS is an intractable disease that causes motor nerves to die. One of the reasons for this has been given as oxidant stress.
Commenting on the findings, team leader Yoshiho Ikeuchi said, "It can be expected that this will help clarify the onset mechanisms of ALS, and also lead to the development of new treatments."
The team has released its findings in the online American science journal, "Stem Cell Reports."