Stem Cell Therapy for Spinal Cord Injury

Spinal cord injury (SCI) causes permanent or near-permanent loss of movement and sensation because the adult spinal cord has very limited capacity to repair itself. Stem cell therapy — using cells to protect surviving tissue, replace lost support cells, or encourage new connections — is one of the most closely watched research directions in SCI, and a handful of small human trials have produced genuinely encouraging early signals. This article summarizes where the science actually stands, including what's approved, what's still experimental, and what the real trial data show.

How It's Thought to Work

Most experimental approaches fall into a few categories: mesenchymal stem cells (MSCs, often from bone marrow or fat) that are thought to calm inflammation and support the injured cord's own repair processes; oligodendrocyte progenitor cells, which aim to rebuild the myelin sheath that insulates nerve fibers; and neural stem/progenitor cells derived from induced pluripotent stem cells (iPSCs), which are designed to integrate into the injury site and support nerve signaling. None of these mechanisms restores a severed spinal cord to normal function — the realistic goal in current trials is partial recovery of motor or sensory function, not a cure.

What the Evidence Shows

The most exciting recent data come from Japan. In a first-in-human trial led by Keio University and Sumitomo Pharma, patients with subacute spinal cord injury received transplants of iPSC-derived neural stem/progenitor cells; researchers reported no tumor formation and no serious adverse events attributable to the cells through up to four years of follow-up, with motor function and AIS grade improvements at 52 weeks that exceeded a historical comparison group. That safety track record, sustained across years rather than months, is a meaningful milestone for a cell therapy this novel.

The oldest and largest dataset comes from Lineage Cell Therapeutics' AST-OPC1 program (formerly Asterias' SCiStar trial): among 25 patients with severe cervical injuries followed for 12 months, 95% gained at least one motor level on at least one side, and nearly a third gained two or more levels, alongside a favorable MRI safety profile — genuinely strong numbers for a Phase 1/2a study, though it lacked a control arm. Lineage has since launched a new device-delivery study (DOSED) that, for the first time, will include patients with chronic (not just recent) injuries.

Smaller but still notable: a Mayo Clinic Phase I trial (published in Nature Communications) of intrathecally delivered adipose-derived MSCs found no serious adverse events in 10 patients, and 7 of 10 showed improvement in AIS grade — though the authors caution that roughly 5% of similarly injured patients recover spontaneously, and there was no control group. In Japan, Nipro's Stemirac (autologous bone-marrow MSCs) received conditional, time-limited regulatory approval in 2018, but Japan's own review agency (PMDA) based that approval on just 13 treated patients in an uncontrolled, single-site study and required further post-marketing evidence.

Critically, no stem cell therapy is FDA-approved for spinal cord injury in the United States. The only FDA-approved stem cell products are cord-blood-derived cells for certain blood disorders, and the FDA has repeatedly warned that unapproved clinics marketing stem cell "treatments" for SCI carry real risks, including tumor formation and infection.

Who Might Be a Candidate

• People enrolled in an active, registered clinical trial (searchable on ClinicalTrials.gov) under medical supervision
• Individuals with subacute injuries within the enrollment windows most trials use (often 3-6 weeks post-injury), since most positive data come from this window
• Patients willing to accept unknown, unproven benefit in exchange for contributing to research
• Those who have discussed risks — including infection, unexpected tissue growth, and no guarantee of benefit — with a spine specialist
• Not a candidate: anyone considering a direct-to-consumer stem cell clinic offering SCI "treatment" outside a registered trial

Bottom Line

Stem cell therapy for spinal cord injury remains experimental, but the trajectory of the evidence is genuinely encouraging: multiple independent trials — from Japan's iPSC program to Lineage's AST-OPC1 — have now shown consistent, multi-year safety and measurable functional gains in a meaningful share of participants. That said, every study to date is small, mostly uncontrolled, and short of the rigorous, placebo-controlled evidence needed for approval. No stem cell therapy is FDA-approved for SCI, and patients should pursue this only through legitimate, registered clinical trials.