Regenerative Neural Stem Cell Therapy Improves Multidomain Neurological Deficits after Traumatic Brain Injury in Nonhuman Primates

M Arredondo and colleagues tested a cryopreserved, GMP-like human neural stem-cell product called pd.S6.133.hNSC in 18 common marmosets after controlled cortical impact. Seven weeks after injury, animals received MRI-guided stereotactic transplantation into the perilesional cortex. Vehicle, 1 million cells, and 5 million cells were compared under tacrolimus immunosuppression. At three months, the 5-million-cell group improved executive and problem-solving performance, gait dynamics, anxiety-like behavior, and actigraphy-derived sleep-wake measures relative to vehicle and the lower dose. Serial 7-T MRI showed a dose-dependent reduction in lesion volume and preservation of corpus-callosum white-matter volume. The authors reported no observed adverse events over 1,197 cumulative post-transplant animal-days. Histopathology showed engraftment without tumor formation or abnormal tissue overgrowth at three months. This is a preprint in nonhuman primates. It does not establish human efficacy, long-term tumor safety, or a clinically practical delivery protocol. It supports further translational work, not clinic treatment.

These findings support the safety and multidomain efficacy of a cryopreserved hNSC product in a nonhuman primate TBI model and inform translational development toward first-in-human testing with clinically aligned endpoints.