Stem Cell Transplants Improve Movement in 2 Paralyzed Patients

A groundbreaking study from Japan is offering new hope to those living with spinal cord injuries. Researchers at Keio University recently announced that two out of four paralyzed patients who received transplants of cells derived from induced pluripotent stem (iPS) cells showed significant improvements in their motor functions. One patient can now stand, and both can eat independently—a major milestone for those who lost sensation and movement below the neck or chest. This development, paired with other global efforts, signals a promising era for spinal cord injury treatments.

Japan’s Game-Changing Stem Cell Trial

At a recent meeting of the Japanese Society for Regenerative Medicine in Yokohama, a team led by Keio University’s Professors Masaya Nakamura and Hideyuki Okano shared their findings. From 2021 to 2023, they transplanted about two million nerve-forming cells, created from healthy human iPS cells, into the spinal cords of four patients. These patients, all 18 or older, had suffered spinal cord injuries two to four weeks prior, leaving them with complete paralysis (grade A on a five-level scale, where E is normal function).

One year later, the results were striking. One patient’s motor function jumped three ranks to grade D, allowing them to practice walking with rehabilitation. Another improved two ranks, regaining the ability to eat independently. The other two patients didn’t advance in rank but showed some progress. Importantly, the study, primarily focused on safety, reported no serious adverse effects.

Magnetic resonance imaging revealed a key clue: in one patient, a previously hollow, damaged area in the spinal cord appeared filled post-treatment. “It’s possible the transplanted cells have engrafted and are increasing the number of nerves,” said Professor Toru Ogata of the University of Tokyo. The team believes the cells may be repairing damage, a rare outcome for grade-A paralysis patients.

With about 6,000 new spinal cord injury cases annually in Japan and over 100,000 people living with chronic paralysis, these findings resonate deeply. “I feel like I can see a beacon of hope,” said Makoto Ohama, chairman of the Japan Spinal Cord Foundation, after attending the presentation.

Global Efforts in Spinal Cord Injury Research

Japan’s study is part of a broader global push to transform spinal cord injury treatment. Researchers worldwide are exploring innovative approaches, from stem cells to neurostimulation and robotics, to restore function and improve quality of life.

United States: Stem Cells and Neurostimulation

In the U.S., companies like Neuralstem and Asterias Biotherapeutics (now part of Lineage Cell Therapeutics) are advancing stem cell therapies. Recently, Lineage Cell Therapeutics has launched the DOSED clinical study to assess the safety and utility of its novel Manual Inject Parenchymal Spinal Delivery (MI PSD) System. This device is designed to deliver OPC1—an investigational allogeneic stem cell-derived therapy composed of oligodendrocyte progenitor and glial cells—directly to spinal cord injury (SCI) sites. OPC1 aims to restore or support damaged spinal cells, potentially improving mobility and quality of life. The study will enroll both subacute (21–42 days post-injury) and chronic (1–5 years post-injury) SCI patients. 

Mayo Clinic researchers have published promising results from the phase 1 CELLTOP trial, demonstrating the safety and potential benefit of autologous adipose-derived mesenchymal stem cell (AD-MSC) therapy for patients with subacute and chronic spinal cord injury. Ten participants with traumatic AIS grade A or B injuries received treatment approximately 11 months post-injury and were monitored for two years. No serious adverse events occurred, and seven patients showed neurological improvement, including one superresponder with notable limb function gains. Ongoing research aims to refine treatment protocols and explore the mechanisms behind varied patient responses.

Meanwhile, in 2024, University of California, San Diego researchers reported that neural stem cell transplants in spinal cord injury patients were safe and showed early signs of improving motor and sensory functions in a small-scale trial

Switzerland: Bridging the Gap with Technology

Switzerland is making waves with neurotechnology. The Swiss Federal Institute of Technology (EPFL) and Lausanne University Hospital have developed implantable devices that deliver targeted electrical pulses to the spinal cord. In 2024, two patients with incomplete spinal cord injuries regained the ability to walk unaided and climb stairs after receiving hypothalamic deep brain stimulation implants and undergoing rehabilitation. The team, led by Professor Grégoire Courtine, is now working to adapt this technology for complete paralysis cases, with clinical trials planned for 2026.

Australia: Exoskeletons and Rehabilitation

In Australia, researchers are focusing on robotics and exoskeletons to complement biological treatments. The ALEX (Advanced Lower Extremity Exoskeleton) project, based at the University of Melbourne, involves Master of Engineering students in mechanical and mechatronics systems working to improve the Fourier X2 exoskeleton. Partnered with Fourier Intelligence and the University’s Robotics Laboratory, the team initially prepared for the CYBATHLON 2020 Powered Exoskeleton Race, where pilots with complete spinal cord injuries use exoskeletons for daily tasks. Due to COVID-19 and time constraints, they withdrew from the competition but continue development through capstone projects under Professor Ying Tan. The project includes specialized teams, like Computer Vision and Coordination, and focuses on advancing gait rehabilitation technology, though social media updates are limited due to access issues.

Similarly, evidence suggests that patients using robotic exoskeletons during rehabilitation improved their muscle strength and coordination faster than those undergoing traditional therapy. These devices, while not a cure, are helping patients regain independence while researchers work on regenerative solutions.

Challenges and Next Steps

While these advances are exciting, challenges remain. Japan’s study showed improvement in only half the patients, possibly due to varying injury severity. The small sample size—four patients—limits conclusions about efficacy. Nakamura’s team plans to increase the number of transplanted cells and expand trials to include patients with chronic paralysis by 2027. “The key will be proving efficacy with more successful cases,” said Professor Kinichi Nakashima of Kyushu University.

Globally, researchers face similar hurdles. Stem cell therapies must balance safety and effectiveness, as excessive cell growth could lead to tumors. Neurostimulation and robotics, while promising, are costly and not yet widely accessible. Standardizing treatments across diverse patient populations is another obstacle, as injury types and recovery windows vary.

For patients, these developments mean more than just medical progress—they offer a chance at independence. Whether it’s eating a meal, standing, or taking a step, each milestone counts. As research accelerates, the global scientific community is inching closer to turning paralysis into a condition with viable treatment options.

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Author

Bernice Lottering