Meta-Analysis of the Safety and Efficacy of Stem Cell Therapies for Ischemic Stroke in Preclinical and Clinical Studies.

Recent studies have indicated that stem cell transplantation may be effective in the treatment of ischemic stroke. Therefore, we performed a meta-analysis to evaluate the safety and efficacy of stem cell therapy for ischemic stroke in preclinical and clinical studies. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched the PubMed, Cochrane Library, Embase, Web of science, and Ovid databases from inception through May 2018. A total of 11 preclinical studies-18 independent interventions were ultimately included. Similarly, 11 clinical studies were finally included. Two authors independently screened trials. Lesion volume and modified neurological severity scores (mNSSs) were regarded as outcome measures for preclinical studies. The composite weighted mean [95% confidence interval (CI)] effect sizes for lesion volume, percentage of lesion volume, and mNSSs were -46.59 (-62.04 to -31.15; P < 0.001), -13.18 (-25.62 to -0.73; P = 0.04), and -1.85 (-2.17 to -1.53; P < 0.001), respectively. Our analysis revealed that all three outcomes were significantly more favorable in the stem cell group than in the control group. Barthel index (BI) values, modified Rankin scale (mRS) scores, National Institutes of Health Stroke Scale (NIHSS) scores, and Fugl-Meyer assessment (FMA) scores were regarded as outcome measures for human studies. Our results were as follows: NIHSS [mean differences, MDs = -2.57, 95% CI (-3.45 to -1.68), I2 = 51%, P < 0.001]; BI [MD = 7.93, 95% CI (3.11 to 12.75), I2 = 59%, P = 0.001]; mRS [MD = -0.53, 95% CI (-0.73 to -0.28), I2 = 0%, P < 0.001]; FMA [MD = 5.50, 95% CI (2.05 to 8.95), I2 = 15%, P = 0.002]. These results suggest that stem cell transplantation was associated with significantly better outcomes than control treatment. Adverse reactions such as mild headache and fever resolved shortly after treatment. Stem cell transplantation can significantly improve neurological deficits and quality of life in patients with ischemic stroke, without severe adverse reactions. Our results also suggest that such treatment is most effective when provided earlier and through the intravenous route.

Oncostatin M-induced upregulation of SDF-1 improves Bone marrow stromal cell migration in a rat middle cerebral artery occlusion stroke model.

Bone marrow-derived mesenchymal stem cells (BMSCs) exhibit potential regenerative effects on the injured brain. However, these effects are constrained by their limited ability to migrate to the injured site. Oncostatin M (OSM) has been shown to affect the proliferation and migration of mesenchymal stem cells. Therefore, in the present study, we explored whether OSM improves BMSC migration and secretion of growth factors and cytokines in a rat middle cerebral artery occlusion (MCAO) stroke model. The effect of OSM on the proliferation and apoptosis of rat BMSCs was first assessed in vitro, and the gene and secretion levels of factors related to cell nutrition and migration, such as SDF-1 and VEGF, were detected. To further explore underlying pathways triggered by OSM, BMSCs were treated with OSM in the presence or absence of inhibitors of the STAT3 and ERK pathways. Effects of OSM on SDF-1 expression in astrocytes and BMSC migration were also evaluated. In the rat MCAO model, OSM secretion levels were detected in the brain for up to 72 h after model establishment. Ventricle injection of OSM alone or OSM combined with caudal vein graft of BMSCs was then performed in MCAO stroke rats. After 72 h, production of SDF-1 and grafted BMSCs was detected in the lesion areas of the brain, and the nerve function score was evaluated. We found that the production of OSM continually increased in the brains of MCAO rats from 12 h to 72 h. OSM significantly upregulated SDF-1 in BMSCs via the STAT3 and ERK pathways and significantly promoted the expression of VEGF and MMP-2. OSM also promoted the secretion of SDF-1 in astrocytes through the STAT3 and ERK pathways to in turn enhance BMSC migration. Combination treatment with OSM and BMSCs in MCAO rats increased the migration efficiency of BMSCs in the brain, which significantly improved neurofunctional recovery while reducing the expression of inflammatory mediators and promoting the secretion of nutrition factors. Overall, these results show that OSM is highly expressed in the brains of MCAO stroke rats and can upregulate SDF-1 to promote BMSC migration. Thus, combination treatment with OSM and BMSCs improves the graft efficiency of BMSCs and neurofunctional recovery.

CBX2 Inhibits Neurite Development by Regulating Neuron-Specific Genes Expression.

Polycomb group (PcG) proteins regulate the epigenetic status of transcription regulatory states during development. Progression from pluripotency to differentiation requires the sequential activation and repression of different PcG target genes, however, the relationship between early patterning signals, PcG expression, and the development of the central nervous system is still unclear. Using various models of neuronal differentiation, we provide evidence that CBX2 is a negative regulator of neuronal differentiation. Knock-down of CBX2 expression promotes neurite development, while overexpression of CBX2 inhibits neurite development. Further, we found that CBX2 is a direct target gene of miR-124. During neuronal differentiation, CBX2 was decreased while miR-124 was increased. Mechanistically, CBX2 directly interacts with the promoter region of several neuro-associated genes and regulates their expression. We found that the neuron-specific GAP-43 gene could contribute to the stimulating effect on neurite development associated with inhibition of CBX2.