Study of the efficiency of transplantation of human neural stem cells to rats with spinal trauma: the use of functional load tests and BBB test

Spinal cord neural stem cells derived from human embryonic stem cells promote synapse regeneration and remyelination in spinal cord injury model rats

Spinal cord injury (SCI) is a devastating injury that significantly impairs patients' quality of life. To date, there is no effective treatment to mitigate nerve tissue damage and restore neurological function. Neural stem cells (NSCs) derived from human embryonic stem cells (hESCs) are considered an important cell source for reconstructing damaged neural circuits and enabling axonal regeneration. Recent preclinical studies have shown that NSCs are potential therapeutic cell sources for neuroprotection and neuroregeneration in SCI animal models. NSCs can be derived from different sources and the spinal cord-specific NSCs have a higher potential for the regeneration of SCI. However, the long-term therapeutic efficacy of spinal cord-specific NSCs remains unproven. Here, we generated human spinal cord NSCs (hSCNSCs) and investigated the effects of transplanted hSCNSCs on the repair of the SCI model rats for 60 days. The transplanted hSCNSCs improved BBB scores, reduced the lesion area and promoted an increase in the number of Nestin-positive cells in the spinal cord compared to the model rats. Meanwhile, hSCNSC transplantation promoted the expression of synaptophysin, a synaptic signature protein and MBP, a protein associated with remyelination. Interestingly, BAF45D, a chromatin remodelling factor that contributes to the induction of hSCNSCs with region-specific spinal cord identity, were increased by the hSCNSC transplantation. In addition, conditioned medium derived from the hSCNSCs also promoted regenerative repair of the injured spinal cord. These results demonstrate that hSCNSCs may play a critical role in the regenerative repair of SCI.

The Effect of Transplantation of Olfactory Ensheathing Cells on the Size of Posttraumatic Spinal Cord Cysts

We studied the effect of transplantation of ensheathing cells obtained from the olfactory mucosa of rats and humans on the size of posttraumatic spinal cord cysts. MRI examination showed that transplantation of these cells into experimental posttraumatic cysts of the spinal cord led to a significant decrease in cyst volume and even their complete disappearance in two animals receiving transplantation of rat or human cells. These findings attested to regenerative processes developing as a result of ensheathing cell transplantation. Further studies in this field will be aimed at elucidation of the mechanisms underlying spinal cord regeneration in the area of posttraumatic cysts after transplantation of ensheathing cells.

Preparation of Adhesion Culture of Neural Stem/Progenitor Cells of the Olfactory Mucosa for the Treatment of Spinal Cord Injuries

In this work, an optimal protocol was developed for obtaining adhesion culture of neural stem/progenitor cells (NSPC) of rat olfactory mucosa. During the development of the protocol, the conditions for cell culturing on adhesion substrates fibronectin and laminin in DMEM/F-12 and neurobasal media with the same culture additives were compared. Cell proliferation was maximum during culturing on both substrates in the neurobasal medium. Using the immunofluorescence method, we found that culturing on fibronectin in the neurobasal medium ensured maximum (52.22%) content of nestin-positive cells in comparison with other culturing conditions. The highest percentage of βIII-tubulin-positive cells was detected in cultures growing on fibronectin in the neurobasal medium and in DMEM/F-12 (79.11 and 83.52%, respectively). Culturing in adhesion cultures in the neurobasal medium on fibronectin allowed obtaining cultures enriched with NSPC and neurons differentiating from them in a quantity sufficient for further transplantation. The developed protocol can be recommended for obtaining NPSC from human olfactory mucosa for the treatment of spinal cord injuries.

Neural Stem/Progenitor Cells of Human Olfactory Mucosa for the Treatment of Chronic Spinal Cord Injuries

We studied the efficiency of transplantation of neural stem/progenitor cells from human olfactory mucosa in chronic spinal cord injury. Neural stem/progenitor cells were obtained by a protocol modified by us and transplanted to rats with spinal post-traumatic cysts. It was shown that transplantation of neural stem/progenitor cells from human olfactory lining improved motor activity of hind limbs in the recipient rat with spinal post-traumatic cysts (according to BBB scale).

Effects of neural stem cell transplantation on the motor function of rats with contusion spinal cord injuries: a meta-analysis

Objective

To judge the efficacies of neural stem cell (NSC) transplantation on functional recovery following contusion spinal cord injuries (SCIs).

Data sources

Studies in which NSCs were transplanted into a clinically relevant, standardized rat model of contusion SCI were identified by searching the PubMed, Embase and Cochrane databases, and the extracted data were analyzed by Stata 14.0.

Data selection

Inclusion criteria were that NSCs were used in in vivo animal studies to treat contusion SCIs and that behavioral assessment of locomotor functional recovery was performed using the Basso, Beattie, and Bresnahan lo-comotor rating scale. Exclusion criteria included a follow-up of less than 4 weeks and the lack of control groups.

Outcome measures

The restoration of motor function was assessed by the Basso, Beattie, and Bresnahan locomotor rating scale.

Results

We identified 1756 non-duplicated papers by searching the aforementioned electronic databases, and 30 full-text articles met the inclusion criteria. A total of 37 studies reported in the 30 articles were included in the meta-analysis. The meta-analysis results showed that transplanted NSCs could improve the motor function recovery of rats following contusion SCIs, to a moderate extent (pooled standardized mean difference (SMD) = 0.73; 95% confidence interval (CI): 0.47-1.00; P < 0.001). NSCs obtained from different donor species (rat: SMD = 0.74; 95% CI: 0.36-1.13; human: SMD = 0.78; 95% CI: 0.31-1.25), at different donor ages (fetal: SMD = 0.67; 95% CI: 0.43-0.92; adult: SMD = 0.86; 95% CI: 0.50-1.22) and from different origins (brain-derived: SMD = 0.59; 95% CI: 0.27-0.91; spinal cord-derived: SMD = 0.51; 95% CI: 0.22-0.79) had similar efficacies on improved functional recovery; however, adult induced pluripotent stem cell-derived NSCs showed no significant efficacies. Furthermore, the use of higher doses of transplanted NSCs or the administration of immunosuppressive agents did not promote better locomotor function recovery (SMD = 0.45; 95% CI: 0.21-0.70). However, shorter periods between the contusion induction and the NSC transplantation showed slightly higher efficacies (acute: SMD = 1.22; 95% CI: 0.81-1.63; subacute: SMD = 0.75; 95% CI: 0.42-1.09). For chronic injuries, NSC implantation did not significantly improve functional recovery (SMD = 0.25; 95% CI: -0.16 to 0.65).

Conclusion

NSC transplantation alone appears to be a positive yet limited method for the treatment of contusion SCIs.

Activation of expression of brain-derived neurotrophic factor at the site of implantation of allogenic and xenogenic neural stem (progenitor) cells in rats with ischemic cortical stroke

Ischemic stroke was modeled in the sensorimotor zone of the brain cortex in adult rats. Rat embryonic nervous tissue, neural stem cells from human olfactory epithelium, and rat fibroblasts (cell control) were implanted into the peri-infarction area of rats of different groups immediately after stroke modeling. Expression of BDNF mRNA was analyzed 7 days after surgery by real-time PCR. BDNF expression in cell preparation before their implantation was minimum. The expression of BDNF mRNA increased by 5-6 times in the areas of implantation of rat fibroblasts and human olfactory epithelium and by 23 times in the area of implantation of rat embryonic nervous tissue compared to periinfarction areas without cell implantation. These findings confirm the possibility of realization of the therapeutic effects of neural stem cells via expression of trophic factors.