Paralyzed man can stand again after receiving 'reprogrammed' stem cells

Paralyzed man can stand again after receiving 'reprogrammed' stem cells

A paralyzed man can stand on his own two feet again after receiving an injection of neural stem cells to treat his spinal cord injury. The Japanese man was one of four subjects in one Pilot test, who used reprogrammed stem cells to treat completely paralyzed individuals.

Another participant can now move his arms and legs, while the other two showed no significant improvement. The study was led by Hideyuki Okano, a stem cell scientist at Keio University in Tokyo, and his colleagues.

The results, announced at a news conference on March 21 and not yet peer-reviewed, suggest the treatment is safe, the researchers say.

"This is a great positive result. It's very exciting for the field," said James St John, a translational neuroscientist at Griffith University on the Gold Coast, Australia.

Previous studies using other types of stem cells have also shown the therapy to be safe, but have so far produced mixed results. “So far nothing has really worked,” says St John.

Larger studies will be necessary to determine whether the improvements observed in the two subjects in the current study are actually due to the treatment. It could also be that the patients experienced a natural recovery, adds St John.

In 2019, around 0.9 million people worldwide suffered a spinal cord injury, and around 20 million people were living with the condition 1.

Reprogrammed cells

Reprogrammed or induced pluripotent stem (iPS) cells are created by returning adult cells to an embryonic state from which they can develop into other cell types.

In this study, donor-derived iPS cells were used to generate neural progenitor cells. Two million of these cells were injected into each patient's injury site in the hope that they would eventually develop into neurons and glial cells.

The first operation of the trial took place in December 2021; the other three were carried out between 2022 and 2023. All four recipients were adult men, two of whom were 60 years of age or older. The surgery was performed between two and four weeks after the damage, Okano explains. Recipients were given immune-suppressing drugs to prevent their bodies from attacking the cells within the first six months after surgery.

The results are the latest in a series of small human studies testing the potential of iPS cells to to regenerate tissue and to treat diseases.

Learning to walk

At the one-year follow-up, researchers observed no serious side effects.

All participants began the trial with the highest injury classification, A, as measured by the American Spinal Injury Association Impairment Scale (AIS). Individuals with this level of impairment have no sensory or motor function below the point of injury. Two of the participants showed no improvement in feeling or ability to move in the lowest portion of their spinal cord. One subject achieved classification C after surgery and can move some of his arm and leg muscles but cannot stand independently. Another subject improved to a classification of D (normal function is classified as E) and can now stand independently. “This person is now training to walk,” Okano says. “This is a dramatic recovery.”

Preliminary analyzes of the data suggest the treatment is effective, Okano said.

1. Ding, W. et al. Spine 47, 1532–1540 (2022).

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2. Muheremu, A., Shu, L., Liang, J., Aili, A. & Jiang, K. Transl. Neurosci. 12, 494–511 (2021).

   Article
   PubMed
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