Biological Markers of Mesenchymal Stromal Cells as Predictors of Response to Autologous Stem Cell Transplantation in Patients With Amyotrophic Lateral Sclerosis: An Investigator-Initiated Trial and In Vivo Study

Abstract

Bone marrow mesenchymal stromal cells (MSCs) can modify disease progression in amyotrophic lateral sclerosis (ALS) model. However, there are currently no accurate biological markers for predicting the efficacy of autologous MSC transplants in ALS patients. This open-label, singlearm, investigator-initiated clinical study was designed to identify markers of MSCs that could be used as potential predictors of response to autologous MSC therapy in patients with ALS. We enrolled 37 patients with ALS who received autologous MSCs via intrathecal injection in two monthly doses. After a 6-month follow-up period, the patients were categorized as responders and non-responders based on their scores on the revised ALS Functional Rating Scale (ALSFRS-R). Biological markers including b-fibroblast growth factor-2, stromal cell-derived factor-1a, vascular endothelial growth factor (VEGF), insulin-like growth factor-1, brain-derived neurotrophic factor, angiogenin (ANG), interleukin (IL)24, IL-10, and transforming growth factor-b (TGF-b) were measured in the MSC cultures and their levels were compared between the responders and nonresponders. To confirm the markers' predictive ability, MSCs isolated from one patient in each group were transplanted into the cisterna magna of mutant SOD1G93A transgenic mice to measure their lifespans, locomotor activity, and motor neuron numbers. The levels of VEGF, ANG, and TGF-b were significantly higher in responders than in nonresponders. In the mouse model, the recipients of responder MSCs had a significantly slower onset of symptoms and a significantly longer lifespan than the recipients of nonresponders or controls. Our data suggest that VEGF, ANG, and TGF-b levels in MSCs could be used as potential biological markers to predict the effectiveness of autologous MSC therapy and to identify those patients who could optimally benefit from MSC treatment.

Overcoming immunoregulatory plasticity of mesenchymal stem cells for accelerated clinical applications

“…Furthermore, in a recent study of MSC therapy in ALS patients, it was demonstrated that immunomodulatory factors secreted by MSCs were predictive of the effectiveness of MSC therapy and could potentially identify the patients responsive to therapy. Although the clinical outcomes following MSC therapy did not differ significantly from those of the control groups, ALS patients who responded to MSC therapy showed enhanced levels of immunomodulatory factors, such as VEGF and TGF-β, in the remnant MSC specimens following administration, compared with non-responders [37].…”

Mesenchymal Stem Cells Modulate the Functional Properties of Microglia via TGF-β Secretion

“…In the present study, our results suggest that TGF‐β secreted by MSCs plays a central role on skewing the classically activated M1 phenotype toward a protective M2 phenotype by inhibiting the NF‐κB pathway and leading to a reduction of proinflammatory cytokine expression in LPS‐stimulated microglia. Previously, we proposed that TGF‐β might be a biological marker associated with the efficacy of MSCs administered intrathecally to ALS patients [25]. Interestingly, the TGF‐β concentration in microglia culture medium was similar to the cerebrospinal fluid (CSF) of ALS patients (TGF‐β: 600–800 pg/ml) before intrathecal MSCs injection (supplemental online Fig.…”

“…When the MSC number reached 1.3 × 10 7 (7 days after 2 × 10 5 MSC seeding), the maximum cell number in a 75T flask, the CX3CL1 concentration was 477.75 pg/ml, which was still less than 10 ng/ml (data not shown). Only 1–2 × 10 6 MSCs have been administered in most clinical and animal studies, because it is rare to isolate more than 1–2 × 10 6 MSC/kg weight from adults, and most studies have shown maximum efficacy and negligible mortality at the dose of 1 × 10 6 MSCs [20, 23, 25, 33]. Therefore, it seems unlikely that the CX3CL1 concentration in the CSF would reach 10 ng/ml when 1–2 × 10 6 MSCs are administered intrathecally, although we cannot exclude the possibility that the primed MSCs in an inflammatory microenvironment could acquire an immunomodulatory phenotype, enhancing the release of CX3CL1 and TGF‐β, as in previous studies [25, 30].…”

Functional Restoration of Amyotrophic Lateral Sclerosis Patient-Derived Mesenchymal Stromal Cells Through Inhibition of DNA Methyltransferase

“…Four remnant and stored ALS patient-derived BM-MSCs from a previous investigational clinical trial (Kim et al 2014) approved by the Institutional Review Board (HYUH IRB 2006-339) and the Korean Food and Drug Association (KFDA, Bio-47) were used in this study. The protocol for BM-MSC isolation and culture was described previously (Kim et al 2014).…”

“…The protocol for BM-MSC isolation and culture was described previously (Kim et al 2014). Briefly, mononuclear cells were isolated by bone marrow aspiration at the iliac crest and subjected to a density gradient (Histopaque, density 1.077 g/mL; Sigma-Aldrich, St. Louis, MO, USA).…”