Intraparenchymal Umbilical Cord Mesenchymal Stem Cell Transplantation in Patients with Subacute Ischemic Stroke: A Preliminary Study of Safety and Early Clinical Outcomes

Abstract

BACKGROUND: Intravenous thrombolysis and mechanical thrombectomy are current standard treatments for ischemic stroke, however their narrow therapeutic window limits eligibility for many patients. Umbilical cord-derived mesenchymal stem cells (UC-MSCs) have emerged as a promising regenerative therapy, but their safety and efficacy need to be further elucidated. Interleukin-6 (IL-6) and brain-derived neurotrophic factor (BDNF) may provide biological insights into the inflammatory and neuroregenerative responses following UC-MSC transplantation. This study was conducted to evaluate the safety and preliminary efficacy, including IL-6 and BDNF level, after stereotactic intraparenchymal UC-MSC transplantation.

METHODS: Subjects with subacute ischemic stroke received stereotactic intraparenchymal transplantation of 2×10⁷ allogeneic UC-MSCs into the perolesional ischemic area, 13 to 20 days after stroke onset. Safety was assessed by monitoring the adverse events. Early efficacy was evaluated using the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), Magnetic Resonance Imaging (MRI), and serum biomarkers, including IL-6 and BDNF. Serum IL-6 levels were measured using electrochemiluminescence immunoassay (ECLIA), while BDNF levels were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS: No serious adverse events related to UC-MSCs administration were observed during the three-month follow-up. No serious adverse events related to UC-MSC administration were observed during the three-month follow-up. From baseline to the third month, improved mRS and NIHSS scores were observed (mean Δ: −0.75 and +4.00, respectively), along with reduced IL-6 (mean Δ: −2.76 pg/mL) and increased BDNF (mean Δ: +3.16 ng/mL).

CONCLUSION: UC-MSC transplantation was well tolerated, with improvements in NIHSS and mRS and favorable changes in IL-6 and BDNF levels. These findings suggest that direct intraparenchymal UC-MSCs transplantation may be safe, as no severe adverse events were observed in this preliminary study.

KEYWORDS: ischemic stroke, umbilical cord-derived mesenchymal stem cells (UC-MSCs), interleukin-6, brain-derived neurotrophic factor