Mesenchymal stem cell therapy as adjunctive treatment in pediatric patients with severe acquired brain injury: a single-center retrospective case series.

Objective: Severe acquired brain injury in critically ill children-most commonly hypoxic-ischemic in origin-frequently results in long-term neurological disability. Conventional pediatric intensive care management focuses on preventing secondary brain injury, but therapeutic options targeting neurorestoration remain limited. Mesenchymal stem cells (MSCs), through paracrine, immunomodulatory, anti-inflammatory, and trophic effects, have been proposed as an experimental adjunctive therapy. We aimed to describe the clinical course and short-term neurological outcomes of pediatric patients who received MSC therapy as an adjunct to conventional intensive care in our pediatric intensive care unit (PICU). Patients and methods: This single-center retrospective case series included pediatric patients who received adjunctive MSC therapy in our PICU between January 2019 and August 2023. Demographic and clinical characteristics, conventional treatments received, MSC administration parameters, baseline and follow-up neuroimaging when available, and neurological outcomes were extracted from hospital records. Allogeneic bone marrow- or umbilical cord blood-derived MSCs were administered at a dose of 1-2 × 10 Results: Six patients (5 males, 1 female; median age 65.5 months, range 2-204) received adjunctive MSC therapy. Five had hypoxic brain injury and one had penetrating traumatic brain injury (gunshot wound). All patients had a baseline PCPC of 5 (coma/vegetative state). Median GCS improved from 4 (range 3-5) before MSC therapy to 11 (range 8-15) after the treatment course. PCPC decreased over time (median 5 at baseline, 4 at 1 month, 3 at 6 months). No procedure-related adverse events were observed during MSC administration or during the 6-month follow-up. All six patients survived. Conclusion: In this small retrospective case series, adjunctive MSC therapy was feasible and well tolerated in pediatric patients with severe acquired brain injury, and neurological improvement was observed during follow-up. Because of the small sample size, lack of a control group, heterogeneous etiologies and protocols, and concomitant conventional care and rehabilitation, neurological improvement cannot be attributed to MSC therapy alone. These observations are hypothesis-generating; controlled prospective studies are required to establish efficacy.