Autologous adipose-derived mesenchymal stromal cells for chronic traumatic brain injury

Secondary injury from traumatic brain injury (TBI) leads to a chronic inflammatory process, neurodegeneration, and tissue loss, resulting in poor outcomes. Mesenchymal stromal cell (MSC) treatment can dampen microglial activation and improve TBI outcomes. Our study aimed to assess the impact of autologous adipose-derived MSC treatment in adult patients with chronic TBI using imaging, functional, and neurocognitive outcome measures. Our Phase 1/2a study analyzed safety and treatment effect of 3 intravenous infusions (over 6 weeks) of autologous adipose-derived MSCs (HB-adMSCs) in 24 chronic TBI patients. Outcome measures included functional, neuropsychological, and psychometric testing; multimodal MRI; and PET using [11C]ER176 to measure brain immune cell density. There were no serious treatment-related adverse events. DT-MRI analyses in a priori regions of interest showed that at 6 months after treatment, elevated mean diffusivity volumes (supraMD) were significantly reduced bilaterally in the hippocampus (mean decrease 163.51 mm3, 95% CI -286.55 to -41.51 mm3; P=0.013). A trend for reduced supraMD was observed in the amygdala (mean decrease 113.60 mm3, 95% CI -229.52 to 2.90 mm3; P=0.058); no changes in the insula were observed (P=0.19). Brain-behavior analyses indicated significant interactions between levels in baseline neuropsychological assessments of anxiety and depression and magnitude of supraMD changes in the amygdala and hippocampus, respectively. Macrostructural volumetric changes were not significant in the hippocampus, amygdala, or insula (all P >0.10). PET results showed that HB-adMSC treatment induced significant reductions in brain immune cell density in the right caudate (x,y,z: 12,2,7; T20 = 4.1; P