Effects of Secretome Administration on Serum Interleukin-6, Neurogranin, and Neurological Outcomes in Patients with Spinal Cord Injury: A Pilot Randomized Controlled Trial

Abstract

Spinal cord injury (SCI) can result in persistent neurological disability, while secondary inflammatory responses represent a potential therapeutic target for adjunctive interventions. This single-blind pilot randomized controlled trial investigated whether intrathecal administration of umbilical cord-derived mesenchymal stem cell (UC-MSC) secretome was associated with changes in serum interleukin-6 (IL-6), neurogranin concentrations, and early neurological outcomes following traumatic SCI. Ten patients undergoing surgery were randomly assigned to receive either standard care plus a single intraoperative intrathecal administration of UC-MSC secretome (n = 5) or standard care alone (n = 5). Serum biomarkers were measured preoperatively and at 8 hours, 2 days, and 4 days postoperatively. Neurological and functional outcomes were assessed using the American Spinal Injury Association Impairment Scale (AIS), Spinal Cord Independence Measure (SCIM), and IANR-SCIFRS before surgery and at hospital discharge. Linear mixed-effects models were used to account for repeated measurements, assessment time, age, and sex. Adjusted serum IL-6 concentrations were significantly lower in the secretome group (β = −52.61 pg/mL; 95% confidence interval [CI]: −87.19 to −18.04; p = 0.043). The association with serum neurogranin concentrations did not reach the reported threshold for statistical significance (p = 0.057), while improvements in neurological and functional outcomes did not differ significantly between groups. Baseline differences in biomarker concentrations, the small sample size, and the short follow-up period limited the interpretation and generalizability of these findings. Furthermore, the reported confidence interval and p-value for neurogranin required reconciliation to ensure statistical consistency. These preliminary findings suggested a potential early anti-inflammatory biomarker response following intrathecal UC-MSC secretome administration but did not establish neurological improvement or clinical efficacy in patients with traumatic SCI.