Stem Cell Breakthrough Lets Paralyzed Patient Stand Again

In a remarkable milestone for regenerative medicine, a man paralyzed by a spinal-cord injury is now able to stand on his own after receiving an experimental treatment using reprogrammed stem cells. The early results—from a small, first-in-human clinical trial in Japan—offer a glimpse of new hope for millions living with paralysis.

The study, led by stem-cell scientist Hideyuki Okano and his team at Keio University in Tokyo, involved four men, all with severe spinal-cord injuries classified as AIS-A—the highest level of impairment, meaning no movement or sensation below the injury site.

A First-of-Its-Kind Approach: Reprogramming Adult Cells

Researchers used induced pluripotent stem (iPS) cells, which are created by “rewinding” adult cells to a versatile state that allows them to develop into many different cell types.

For this trial, iPS cells from a donor were turned into neural precursor cells, which have the potential to develop into neurons and glial cells—the key players in transmitting signals in the spinal cord.

Each patient received two million of these cells injected directly into their injury site. They were then given immunosuppressing drugs for six months to prevent rejection.

What Happened After Treatment?

One year after surgery:

• One participant regained enough motor function to stand independently (AIS-D level). He is now training to walk.

• Another participant improved to AIS-C, regaining some arm and leg movement.

• The remaining two showed minimal improvement, similar to the natural recovery sometimes seen after spinal-cord injury.

• Importantly, no serious side effects were reported.

  
  

These early findings suggest that the therapy is safe—a crucial first step for any regenerative medicine trial.

“This is a dramatic recovery,” said Okano, emphasizing that although the study was not designed to test effectiveness, the improvements seen in two individuals are highly encouraging.

Why These Results Matter

Worldwide, nearly 20 million people live with spinal-cord injuries, and current treatments can only manage symptoms—not repair damage. Stem-cell therapies have long been considered a promising direction, but progress has been slow and inconsistent.

iPS cells offer several advantages:

• They can be created ethically from adult cells.

• They can be tailored into specific tissues.

• They may help rebuild damaged neural circuits by:

  • Forming new connections with existing neurons

  • Providing supportive factors that help host cells survive

  • Recreating insulating layers around nerve fibers

However, a major challenge is cell survival—many transplanted cells die or fail to integrate. Early imaging from this trial suggests that some implanted cells survived, a promising sign for future optimization.

What Comes Next?

A Tokyo-based biotech company, K Pharma, co-founded by Okano, plans to launch larger clinical trials to test whether the therapy truly improves mobility—and which types of injuries respond best.

As researchers worldwide push forward with stem-cell–based strategies, this study marks a critical step toward therapies that could one day help people stand, walk, and regain independence after spinal-cord injury.

For now, the results bring a renewed sense of possibility to a field where breakthroughs have been rare.

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Created: Dec 3rd, 2025

Citations:

Mallapaty, Smriti. (2025, March 24). Paralysed man stands again after receiving ‘reprogrammed’ stem cells. Nature. https://www.nature.com/articles/d41586-025-00863-0