Evaluation of Safety and Efficacy of Repeated Mesenchymal Stem Cell Transplantation in Patients with ALS by Investigating Patient's Specific MicroRNAs as Novel Biomarkers: A Retrospective Study

Background: Since there is no cure for amyotrophic lateral sclerosis (ALS) currently, it is very important for searching diagnostic biomarkers and novel treatments to reduce the severity of this disease; one of these treatment approaches is stem cell transplantation. This study aims to evaluate the safety and efficacy of repeated transplantation of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) in patients with ALS by analyzing molecular data. Methods: In this single-centre, open-label, phase II clinical trial, retrospective study, fifteen confirmed ALS patients entered the study based on defined inclusion and exclusion criteria and underwent repeated stem cell transplantation (3 times BM-MSCs transplantation (1×10^6) , MSC/Kg BW per injection) concurrently intrathecally (IT) and intravenously (IV), with one-month interval). Clinical assessment of molecular investigation by evaluating specific microRNAs expression (Mir206, 133a-3p, 338-3p) in the patient's serum and Cerebra spinal fluid (CSF) samples were done three times during the 3-month follow-up. Statistical analysis includes paired T-test or Wilcoxon signed ranks. Results: No serious adverse effects were reported following stem cell transplantation. Besides, the mentioned microRNA expression slightly increased but still non-significant (P>0.05). Conclusions: Although Our study demonstrated non-signifying results. However, the still increasing of these MircRNAs in serum and CSF overall, can indicate that repeated transplantation of BM-MSCs was a safe procedure in ALS patients, leading to delay in disease progression and improvement in clinical symptoms. Future studies are needed to confirm these results.