Effects of bone marrow stromal cell transplantation through CSF on the subacute and chronic spinal cord injury in rats

hBcl2 overexpression in BMSCs enhances resistance to myelin debris-induced apoptosis and facilitates neuroprotection after spinal cord injury in rats

After spinal cord injury (SCI), the accumulation of myelin debris at the lesion exacerbates cell death and hinders axonal regeneration. Transplanted bone marrow mesenchymal stem cells (BMSCs) have been proven to be beneficial for SCI repair, but they are susceptible to apoptosis. It remains unclear whether this apoptotic process is influenced by myelin debris. Here, we constructed rat BMSCs overexpressing human B-cell lymphoma 2 (hBcl2) alone (hBcl2 group), BMSCs overexpressing hBcl2 with an endoplasmic reticulum-anchored segment (hBcl2-cb) (cb group), and a negative control group (NC group) for transplantation in this study. Immunocytochemistry staining validated the successful expression of hBcl2 in BMSCs within the hBcl2 group and cb group. All BMSCs from each group exhibited the ability to phagocytize myelin debris. Nevertheless, only BMSCs derived from the hBcl2 group exhibited heightened resistance to apoptosis and maintained prolonged viability for up to 5 days when exposed to myelin debris. Notably, overexpression of hBcl2 protein, rather than its endoplasmic reticulum-anchored counterpart, significantly enhanced the resistance of BMSCs against myelin debris-induced apoptosis. This process appeared to be associated with the efficient degradation of myelin debris through the Lamp1+ lysosomal pathway in the hBcl2 group. In vivo, the hBcl2 group exhibited significantly higher numbers of surviving cells and fewer apoptotic BMSCs compared to the cb and NC groups following transplantation. Furthermore, the hBcl2 group displayed reduced GFAP+ glial scarring and greater preservation of NF200+ axons in the lesions of SCI rats. Our results suggest that myelin debris triggers apoptosis in transplanted BMSCs, potentially elucidating the low survival rate of these cells after SCI. Consequently, the survival rate of transplanted BMSCs is improved by hBcl2 overexpression, leading to enhanced preservation of axons within the injured spinal cord.

Mesenchymal stem cells overexpressing XIST induce macrophage M2 polarization and improve neural stem cell homeostatic microenvironment, alleviating spinal cord injury

Spinal cord injury (SCI) is a significant cause of disability worldwide, with limited treatment options. This study investigated the potential of bone marrow-derived mesenchymal stem cells (BMSCs) modified with XIST lentiviral vector to modulate macrophage polarization and affect neural stem cell (NSC) microenvironment reconstruction following SCI. Bioinformatics analysis revealed that MID1 might be crucial for BMSCs' treatment of SCI. XIST overexpression enriched Zmynd8 to the promoter region of MID1 and inhibited MID1 transcription, which promoted macrophage M2 polarization. In vitro experiments showed that BMSCs-XIST promoted NSC proliferation, migration, differentiation, and axonal growth by inducing macrophage M2 polarization, suppressing inflammation, and accelerating the re-establishment of the homeostatic microenvironment of NSCs. In vivo, animal experiments confirmed that BMSCs-XIST significantly alleviated SCI by promoting NSC differentiation and axon formation in the injured area. The study demonstrated the potential of XIST-overexpressing BMSCs for treating SCI by regulating macrophage polarization and homeostasis of the NSC microenvironment. These findings provide new insights into the development of stem cell-based therapies for SCI.

Cell transplantation therapies for spinal cord injury focusing on bone marrow mesenchymal stem cells: Advances and challenges

Spinal cord injury (SCI) is a devastating condition with complex pathological mechanisms that lead to sensory, motor, and autonomic dysfunction below the site of injury. To date, no effective therapy is available for the treatment of SCI. Recently, bone marrow-derived mesenchymal stem cells (BMMSCs) have been considered to be the most promising source for cellular therapies following SCI. The objective of the present review is to summarize the most recent insights into the cellular and molecular mechanism using BMMSC therapy to treat SCI. In this work, we review the specific mechanism of BMMSCs in SCI repair mainly from the following aspects: Neuroprotection, axon sprouting and/or regeneration, myelin regeneration, inhibitory microenvironments, glial scar formation, immunomodulation, and angiogenesis. Additionally, we summarize the latest evidence on the application of BMMSCs in clinical trials and further discuss the challenges and future directions for stem cell therapy in SCI models.

Repair Effects of Bone Marrow Mesenchymal Stem Cells on Demyelination of Trigeminal Ganglion in Rats with Trigeminal Neuralgia

Objective

The current study investigated the effects of bone marrow mesenchymal stem cells (BMSCs) on pain behavior in rats with trigeminal neuralgia induced by infraorbital nerve chronic constriction injury (ION-CCI), and the repair effects of BMSCs on pathological changes in trigeminal ganglion demyelination.

Methods

BMSCs or phosphate-buffered saline (PBS) alone were injected around trigeminal ganglion in ION-CCI rats via a rat brain stereotaxic apparatus. Mechanical pain threshold (von Frey test) and face grooming behavior were measured in each group. Recovery of demyelination of trigeminal ganglion was observed via electron microscopy 2 weeks later, and BMSC differentiation was observed via immunofluorescence.

Results

Rats in the BMSC group exhibited significant improvements in mechanical pain threshold and face grooming behavior compared with the PBS group. BMSCs could repair demyelinating changes in trigeminal ganglion in ION-CCI rats. Only cells expressing GFAP, S-100, and p75 were observed via immunofluorescence, and no PKH67-labeled BMSCs were observed in the trigeminal ganglion. No BMSC differentiation was observed in the trigeminal ganglion.

Conclusion

Injection of BMSCs around the trigeminal ganglion could relieve trigeminal neuralgia effectively and repair trigeminal ganglion demyelination. No differentiation of BMSCs injected around the trigeminal ganglion into Schwann cells was observed. The mechanism of trigeminal neuralgia demyelination repair requires further investigation.

Effect of treadmill exercise and bone marrow stromal cell engraftment on activation of BDNF-ERK-CREB signaling pathway in the crushed sciatic nerve

The effect of combined approach of exercise training and bone marrow stromal cell (BMSC) engraftment on activation of brain-derived neurotrophic factor (BDNF)-extracellular signal-regulated kinase 1 and 2 (ERK1/2)-cyclic adenosine monophosphate response element-binding protein (CREB) signaling pathway after sciatic nerve injury (SNI) was investigated. Sixty male Sprague-Dawley rats divided into the normal control, nonexercise (NEX), exercise training (EX), BMSC transplantation (TP), and exercise training+BMSC transplantation (EX+TP) groups 4 weeks after SCI. Exercise training was carried out on the treadmill device at 5-10 m/min for 20 min for 4 weeks. Single dose of 5×10⁶ harvested BMSC was injected into the injury area of the injured sciatic nerve. In order to evaluate induction levels of BDNF-ERK1/2-CREB signaling molecules in the whole cell and nuclear cell lysates of the injured sciatic nerve, we applied Western blot analysis. BDNF was significantly increased only in EX+TP compared to NEX, EX, and TP groups. Phosphoinositide-dependent kinase-1 was more increased in EX, TP, and EX+TP groups than NEX group, but EX+TP group showed the most upregulation of phosphorylated protein kinase B compared to other groups. In addition, in the whole cell lysate, phosphorylated ERK1/2, but not activating transcription factor-3 (ATF-3) and phosphorylated CREB, was significantly increased in TP and EX+TP groups. In the nuclear cell lysate, ATF-3 and phosphorylated CREB were strongly activated in EX+TP group compared to EX group. Regular exercise training combined with BMSC engraftment would seem to be more effective in controlling activation of regeneration-related signaling pathway after SNI.

Effect of treadmill exercise combined with bone marrow stromal cell transplantation on atrophy-related signaling pathway in the denervated soleus muscle

The purpose of this study was to investigate whether combination of low-intensity exercise with bone marrow stromal cell (BMSC) transplantation could regulate protein kinas B (Akt)-mammalian target of rapamycin (mTOR) and Wnt3a-β-catenin signaling pathways for prevention of soleus muscle atrophy after sciatic nerve injury (SNI). The experimental rats divided into 5 groups (n=10): normal control group, SNI+sedentary group (SED), SNI+low-intensity treadmill exercise group (TEX), SNI+BMSC transplantation group (BMSC), SNI+TEX+BMSC transplantation group (TEX+BMSC). Sciatic nerve crush injury was applied into the middle of thigh twice for 1 min and 30 sec at interval. Low-intensity treadmill exercise was comprised of walking at a speed of 4 to 8 m/min for 30 min once a day. cultured BMSC at a density of 5×10⁶ in 50-μL phosphate-buffered saline was injected into the distal portion of the injured sciatic nerves. TEX+BMSC group dramatically up-regulated expression levels of growth-associated protein-43 in the injured sciatic nerve at 2 weeks postinjury. Also, although Akt and mTOR signaling pathway significantly increased in TEX and BMSC groups than SED group, TEX+BMSC group showed more potent increment on this signaling in soleus muscle after SNI. Lastly, Wnt3a and the nuclear translocation of β-catenin and nuclear factor-kappa B in soleus were increased by SNI, but TEX+BMSC group significantly downregulated activity of this signaling pathway in the nuclear cell lysate of soleus muscle. Present findings provide new information that combination of low-intensity treadmill exercise might be effective therapeutic approach on restriction of soleus muscle atrophy after peripheral nerve injury.

A comparative study of different stem cells transplantation for spinal cord injury: a systematic review and network meta-analysis

OBJECTIVE

This study aimed to evaluate the efficacy and safety of different stem cell types for spinal cord injury (SCI) therapy and find out the superior treatment for SCI.

METHODS

A systematic literature search was performed using PubMed, Embase, the Cochrane Library, Web of Science, VIP, CNKI, and Wan Fang from database initiation to January 30, 2021. A Bayesian network meta-analysis was performed using ADDIS software. The PROSPERO registration number was CRD42020129635.

RESULTS

Twelve studies with 642 patients were enrolled in this study. Network meta-analysis revealed that bone mesenchymal stem cells combined with rehabilitation training (BMSCs + R) were significantly more effective than rehabilitation training alone (R) in improving American Spinal Injury Association (ASIA) impairment scale (AIS)-grading improvement rate (OR=94.25, 95% CI: 6.71 to 9321.95), ASIA motor score (WMD=6.67, 95% CI: 0.83 to 12.73), ASIA Sensory Functional score (WMD=12.41, 95%CI: 3.42 to 21.72), and Barthel Index (BI) score (WMD=7.24, 95% CI: 0.21 to 14.30). However, no statistically significant differences were observed between marrow mononuclear cells combined with rehabilitation training (MNCs + R), umbilical cord-derived mesenchymal stem cells combined with rehabilitation training (UCMSCs + R), or UCMSCs alone and R on all indicators. In terms of safety, there were no serious and permanent adverse effects after transplantation of BMSCs, MNCs, or UCMSCs.

CONCLUSION

BMSCs + R may be superior to the other stem cell treatments for SCI in improving AIS grading, ASIA motor score, ASIA Sensory Functional score, and BI score. The therapeutic effects of UCMSCs and MNCs remain to be confirmed.

The Restorative Effect of Human Amniotic Fluid Stem Cells on Spinal Cord Injury

Spinal cord injury (SCI) is a debilitating condition within the neural system which is clinically manifested by sensory-motor dysfunction, leading, in some cases, to neural paralysis for the rest of the patient’s life. In the current study, mesenchymal stem cells (MSCs) were isolated from the human amniotic fluid, in order to study their juxtacrine and paracrine activities. Flow cytometry analysis was performed to identify the MSCs. A conditioned medium (CM) was collected to measure the level of BDNF, IL-1β, and IL-6 proteins using the ELISA assay. Following the SCI induction, MSCs and CM were injected into the lesion site, and also CM was infused intraperitoneally in the different groups. Two weeks after SCI induction, the spinal cord samples were examined to evaluate the expression of the doublecortin (DCX) and glial fibrillary acid protein (GFAP) markers using immunofluorescence staining. The MSCs’ phenotype was confirmed upon the expression and un-expression of the related CD markers. Our results show that MSCs increased the expression level of the DCX and decreased the level of the GFAP relative to the injury group (p < 0.001). Additionally, the CM promoted the DCX expression rate (p < 0.001) and decreased the GFAP expression rate (p < 0.01) as compared with the injury group. Noteworthily, the restorative potential of the MSCs was higher than that of the CM (p < 0.01). Large-scale meta-analysis of transcriptomic data highlighted PAK5, ST8SIA3, and NRXN1 as positively coexpressed genes with DCX. These genes are involved in neuroactive ligand–receptor interaction. Overall, our data revealed that both therapeutic interventions could promote the regeneration and restoration of the damaged neural tissue by increasing the rate of neuroblasts and decreasing the astrocytes.

Spinal cord injury repair using mesenchymal stem cells derived from bone marrow in mice: A stereological study

Transplantation of bone marrow stem cells (BMSCs) has shown to have a vital role in promoting nerve regeneration after SCI. The aim of this study was to investigate the effect of BMSCs transplantation in healing of spinal cord injury (SCI) in mice based on morphologic parameters. Forty two male mice were randomly divided into 3 groups of control with no intervention, experimental SCI without treatment, and experimental SCI transplanted with 2 × 10⁵ BMSCs intravenously. To induce SCI bilaterally, T10 was compressed for 2 min. The animals were sacrificed 3 and 5 weeks after SCI and T7-T11 segments of spinal cord were removed and stained by Giemsa and H&E methods. Stereological assessment estimated the gray and white matter volume, the number of neurons and neuroglia and diameter of central canal. The average amount of gray matter in SCI injury group was significantly lower than control group. An increase in the number of neurons was noted after cell transplantation. The number of neurons in SCI injury group significantly decreased in comparison to the control group. In cell transplantation group, a significant increase in the number of neurons was visible when compared to SCI injury group. The increase in the number of neurons after cell transplantation denotes to the regenerative potential of BMSCs in SCI. These findings can be added to the literature and open a new window when targeting treatment of SCI.

Optimal Ratio of Wnt3a Expression in Human Mesenchymal Stem Cells Promotes Axonal Regeneration in Spinal Cord Injured Rat Model

Objective

Through our previous clinical trials, the demonstrated therapeutic effects of MSC in chronic spinal cord injury (SCI) were found to be not sufficient. Therefore, the need to develop stem cell agent with enhanced efficacy is increased. We transplanted enhanced Wnt3asecreting human mesenchymal stem cells (hMSC) into injured spines at 6 weeks after SCI to improve axonal regeneration in a rat model of chronic SCI. We hypothesized that enhanced Wnt3a protein expression could augment neuro-regeneration after SCI.

Methods

Thirty-six Sprague-Dawley rats were injured using an Infinite Horizon (IH) impactor at the T9-10 vertebrae and separated into five groups : 1) phosphate-buffered saline injection (injury only group, n=7); 2) hMSC transplantation (MSC, n=7); 3) hMSC transfected with pLenti vector (without Wnt3a gene) transplantation (pLenti-MSC, n=7); 4) hMSC transfected with Wnt3a gene transplantation (Wnt3a-MSC, n=7); and 5) hMSC transfected with enhanced Wnt3a gene (1.7 fold Wnt3a mRNA expression) transplantation (1.7 Wnt3a-MSC, n=8). Six weeks after SCI, each 5×105 cells/15 µL at 2 points were injected using stereotactic and microsyringe pump. To evaluate functional recovery from SCI, rats underwent Basso-Beattie-Bresnahan (BBB) locomotor test on the first, second, and third days post-injury and then weekly for 14 weeks. Axonal regeneration was assessed using growth-associated protein 43 (GAP43), microtubule-associated protein 2 (MAP2), and neurofilament (NF) immunostaining.

Results

Fourteen weeks after injury (8 weeks after transplantation), BBB score of the 1.7 Wnt3a-MSC group (15.0±0.28) was significantly higher than that of the injury only (10.0±0.48), MSC (12.57±0.48), pLenti-MSC (12.42±0.48), and Wnt3a-MSC (13.71±0.61) groups (p<0.05). Immunostaining revealed increased expression of axonal regeneration markers GAP43, MAP2, and NF in the Wnt3a-MSC and 1.7 Wnt3a-MSC groups.

Conclusion

Our results showed that enhanced gene expression of Wnt3a in hMSC can potentiate axonal regeneration and improve functional recovery in a rat model of chronic SCI.

Research progress on the regulatory role of microRNAs in spinal cord injury

Spinal cord injury (SCI) is a severe CNS injury that results in abnormalities in, or loss of, motor, sensory and autonomic nervous function. miRNAs belong to a new class of noncoding RNA that regulates the production of proteins and biological function of cells by silencing translation or interfering with the expression of target mRNAs. Following SCI, miRNAs related to oxidative stress, inflammation, autophagy, apoptosis and many other secondary injuries are differentially expressed, and these miRNAs play an important role in the progression of secondary injuries after SCI. The purpose of this review is to elucidate the differential expression and functional roles of miRNAs after SCI, thus providing references for further research on miRNAs in SCI.

Clinical Trials of Stem Cell Treatment for Spinal Cord Injury

There are more than one million patients worldwide suffering paralysis caused by spinal cord injury (SCI). SCI causes severe socioeconomic problems not only to the patients and their caregivers but also to society; therefore, the development of innovative treatments is crucial. Many pharmacological therapies have been attempted in an effort to reduce SCI-related damage; however, no single therapy that could dramatically improve the serious long-term sequelae of SCI has emerged. Stem cell transplantation therapy, which can ameliorate damage or regenerate neurological networks, has been proposed as a promising candidate for SCI treatment, and many basic and clinical experiments using stem cells for SCI treatment have been launched, with promising results. However, the cell transplantation methods, including cell type, dose, transplantation route, and transplantation timing, vary widely between trials, and there is no consensus regarding the most effective treatment strategy. This study reviews the current knowledge on this issue, with a special focus on the clinical trials that have used stem cells for treating SCI, and highlights the problems that remain to be solved before the widespread clinical use of stem cells can be adopted.

Mesenchymal Stem Cell Therapy for Spinal Cord Contusion: A Comparative Study on Small and Large Animal Models

Here, we provide a first comparative study of the therapeutic potential of allogeneic mesenchymal stem cells derived from bone marrow (BM-MSCs), adipose tissue (AD-MSCs), and dental pulp (DP-MSCs) embedded in fibrin matrix, in small (rat) and large (pig) spinal cord injury (SCI) models during subacute period of spinal contusion. Results of behavioral, electrophysiological, and histological assessment as well as immunohistochemistry and real-time polymerase chain reaction analysis suggest that application of AD-MSCs combined with a fibrin matrix within the subacute period in rats (2 weeks after injury), provides significantly higher post-traumatic regeneration compared to a similar application of BM-MSCs or DP-MSCs. Within the rat model, use of AD-MSCs resulted in a marked change in: (1) restoration of locomotor activity and conduction along spinal axons; (2) reduction of post-traumatic cavitation and enhancing tissue retention; and (3) modulation of microglial and astroglial activation. The effect of an autologous application of AD-MSCs during the subacute period after spinal contusion was also confirmed in pigs (6 weeks after injury). Effects included: (1) partial restoration of the somatosensory spinal pathways; (2) reduction of post-traumatic cavitation and enhancing tissue retention; and (3) modulation of astroglial activation in dorsal root entry zone. However, pigs only partially replicated the findings observed in rats. Together, these results indicate application of AD-MSCs embedded in fibrin matrix at the site of SCI during the subacute period can facilitate regeneration of nervous tissue in rats and pigs. These results, for the first time, provide robust support for the use of AD-MSC to treat subacute SCI.

Neuregulin‑1 impacting bone marrow mesenchymal stem cell migration is conducive to functional recovery following spinal cord injury

The present study was designed to investigate the effect of neuregulin-1 (NRG1) on the migration of rat bone marrow mesenchymal stem cells (BMSCs) and evaluate the role of NRG1 in the functional recovery following spinal cord injury (SCI). Firstly, the effect of NRG1 on the mRNA expression of Snail in the BMSCs was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis; secondly, the BMSCs were transfected with a Snail-overexpression plasmid (pBabe-puro-Snail) and the expression levels of Snail and matrix metalloptoreinase-2 (MMP-2) were detected by RT-qPCR and western blot analyses; thirdly, the cell proliferation and migration of BMSCs modified with pBabe-puro-Snail were detected by methyl thiazolyl tetrazolium and migration assays, respectively; finally, functional recovery of SCI was assessed using the Basso, Beattie, and Bresnahan rating scales. The results showed that NRG1 concentration-dependently promoted the expression of Snail with a peak at 40 ng/ml and 48 h; NRG1 enhanced the promoting effect of Snail on the expression of MMP-2; the overexpression of Snail did not enhance the cell growth of the BMSCs. The NRG1-modified BMSCs promoted the functional recovery of SCI. These results suggested that NRG1 significantly promoted the expression of MMP-2 by upregulating the expression of Snail, and enhanced cell migration of the BMSCs conducive to the functional recovery of SCI.

Mesenchymal stem cells and the neuronal microenvironment in the area of spinal cord injury

Cell-based technologies are used as a therapeutic strategy in spinal cord injury (SCI). Mesenchymal stem cells (MSCs), which secrete various neurotrophic factors and cytokines, have immunomodulatory, anti-apoptotic and anti-inflammatory effects, modulate reactivity/phenotype of astrocytes and the microglia, thereby promoting neuroregeneration seem to be the most promising. The therapeutic effect of MSCs is due to a paracrine mechanism of their action, therefore the survival of MSCs and their secretory phenotype is of particular importance. Nevertheless, these data are not always reported in efficacy studies of MSC therapy in SCI. Here, we provide a review with summaries of preclinical trials data evaluating the efficacy of MSCs in animal models of SCI. Based on the data collected, we have tried (1) to establish the behavior of MSCs after transplantation in SCI with an evaluation of cell survival, migration potential, distribution in the area of injured and intact tissue and possible differentiation; (2) to determine the effects MSCs on neuronal microenvironment and correlate them with the efficacy of functional recovery in SCI; (3) to ascertain the conditions under which MSCs demonstrate their best survival and greatest efficacy.

A Potential Competitive Endogenous RNA Pathway Involved in Chronic Spinal Cord Injury

BACKGROUND Chronic spinal cord injury (CSCI) is a worldwide clinical problem. We aimed to reveal differentially expressed (DE) lncRNAs and to find associated pathways that may function as targets for CSCI therapy. MATERIAL AND METHODS After a CSCI rat model was confirmed by the Basso Beattie Bresnahan (BBB) scale and the Magnetic Resonance Imaging (MRI) test, microarray analysis was used to obtain the expression profile of DE lncRNAs between CSCI rats and corresponding control rats. Then, bioinformatics analyses, including GO and KEGG pathway analysis, DE lncRNAs-mRNAs co-expression analysis, and several databases, were used to examine the function of these DE lncRNAs. Finally, quantitative real-time PCR (qRT-PCR) was used to evaluate the expressions of the 5 most significantly changed lncRNAs, Col6a1, and miR-330-3p. RESULTS Our study identified 1266 DE lncRNAs and 847 DE mRNAs, among which lncRNA6032 was significant up-regulated. Furthermore, the expressions of miR-330-3p and Col6a1 associated with lncRNA6032 were down-regulated and up-regulated, respectively. CONCLUSIONS Our results showed that the abundance of DE lncRNAs may be associated with the risk of CSCI outcome and revealed a potential competitive endogenous RNA (ceRNA) pathway involved in CSCI. Further experiments in vivo and in vitro were essential to uncover the exact mechanism of this ceRNA pathway.

Clinical and Neurophysiological Changes after Targeted Intrathecal Injections of Bone Marrow Stem Cells in a C3 Tetraplegic Subject

High-level quadriplegia is a devastating condition with limited treatment options. Bone marrow derived stem cells (BMSCs) are reported to have immunomodulatory and neurotrophic effects in spinal cord injury (SCI). We report a subject with complete C2 SCI who received three anatomically targeted intrathecal infusions of BMSCs under a single-patient expanded access investigational new drug (IND). She underwent intensive physical therapy and was followed for >2 years. At end-point, her American Spinal Injury Association Impairment Scale (AIS) grade improved from A to B, and she recovered focal pressure touch sensation over several body areas. We conducted serial neurophysiological testing to monitor changes in residual connectivity. Motor, sensory, and autonomic system testing included motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), electromyography (EMG) recordings, F waves, galvanic skin responses, and tilt-table responses. The quality and magnitude of voluntary EMG activations increased over time, but remained below the threshold of clinically obvious movement. Unexpectedly, at 14 months post-injury, deep inspiratory maneuvers triggered respiratory-like EMG bursting in the biceps and several other muscles. This finding means that connections between respiratory neurons and motor neurons were newly established, or unmasked. We also report serial analysis of MRI, International Standards for Neurological Classification of SCI (ISNCSCI), pulmonary function, pain scores, cerebrospinal fluid (CSF) cytokines, and bladder assessment. As a single case, the linkage of the clinical and neurophysiological changes to either natural history or to the BMSC infusions cannot be resolved. Nevertheless, such detailed neurophysiological assessment of high cervical SCI patients is rarely performed. Our findings indicate that electrophysiology studies are sensitive to define both residual connectivity and new plasticity.

Treadmill exercise with bone marrow stromal cells transplantation facilitates neuroprotective effect through BDNF-ERK1/2 pathway in spinal cord injury rats

Transplantation of bone marrow stromal cells (BMSCs) has been known as one of the effective therapeutic methods for functional recovery of spinal cord injury (SCI). Treadmill exercise also facilitates the functional recovery of SCI. Previously, we reported that combination of BMSCs transplantation with treadmill exercise potentiated the locomotor function in SCI rats. In the present study, we investigated whether recovery effect of BMSCs transplantation or treadmill exercise appears through the brain-derived neurotrophic factor (BDNF)-extracellular signal–regulated kinases 1/2 (ERK1/2) pathway. The spinal cord contusion injury was performed at the T9–T10 level using the impactor. Cultured BMSCs were transplanted directly into the lesion 1 week after SCI. Treadmill exercise was performed 6 days per a week for 6 weeks. Western blot for Bax, Bcl-2, BDNF, tyrosine kinase B (TrkB), and phosphorylated ERK1/2 (p-ERK1/2), phosphorylated JNK was performed. In the present results, combination of BMSCs transplantation with tread-mill exercise potently decreased Bax expression, potently increased Bcl-2 expression, and potently enhanced BDNF and TrkB expressions in the injured spinal cord. Combination of BMSCs transplantation with treadmill exercise further facilitated p-ERK1/2 and p-c-Jun expression levels. The present findings demonstrated the synergistic effect of treadmill exercise on neuroregenerative effect of BMSCs transplantation appeared through the activation of BDNF-ERK1/2 pathway in SCI.

Repeated injections of human umbilical cord blood-derived mesenchymal stem cells significantly promotes functional recovery in rabbits with spinal cord injury of two noncontinuous segments

Background

Spinal cord injuries (SCIs) are sustained by an increasing number of patients each year worldwide. The treatment of SCIs has long been a hard nut to crack for doctors around the world. Mesenchymal stem cells (MSCs) have shown benefits for the repair of SCI and recovery of function. Our present study aims to investigate the effects of intravenously infused human umbilical cord blood-derived MSCs (hUCB-MSCs) on functional recovery after subacute spinal cord compression injury of two noncontinuous segments. In addition, we compared the effects of single infusion and repeated intravenous (i.v.) injections on the recovery of spinal cord function.

Methods

A total of 43 adult rabbits were randomly divided into four groups: control, single injection (SI), repeated injection at a 3-day (3RI) or repeated injection at a 7-day interval (7RI) groups. Non-immunosuppressed rabbits in the transplantation groups were infused with either a single complete dose or three divided doses of 2 × 10⁶ hUCB-MSCs (3-day or 7-day intervals) on the first day post decompression. Behavioural scores and somatosensory evoked potentials (SEPs) were used to evaluate hindlimb functional recovery. The survival and differentiation of the transplanted human cells and the activation of the host glial and inflammatory reaction in the injured spinal cord were studied by immunohistochemical staining.

Results

Our results showed that hUCB-MSCs survived, proliferated, and primarily differentiated into oligodendrocytes in the injured area. Treatment with hUCB-MSCs reduced the extent of astrocytic activation, increased axonal preservation, potentially promoted axonal regeneration, decreased the number of Iba-1+ and TUNEL+ cells, increased the amplitude and decreased the onset latency of SEPs and significantly promoted functional improvement. However, these effects were more pronounced in the 3RI group compared with the SI and 7RI groups.

Conclusions

Our results suggest that treatment with i.v. injected hUCB-MSCs after subacute spinal cord compression injury of two noncontinuous segments can promote functional recovery through the differentiation of hUCB-MSCs into specific cell types and the enhancement of anti-inflammatory, anti-astrogliosis, anti-apoptotic and axonal preservation effects. Furthermore, the recovery was more pronounced in the rabbits repeatedly injected with cells at 3-day intervals. The results of this study may provide a novel and useful treatment strategy for the transplantation treatment of SCI.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-0879-0) contains supplementary material, which is available to authorized users.

Rat vibrissa dermal papilla cells promote healing of spinal cord injury following transplantation

Bone marrow mesenchymal stem cell (BMSC) transplantation is effective for repairing spinal cord injuries (SCIs); however, there are limitations of clinical BMSC applications. Previously, we reported that dermal papilla cells (DPCs) secrete brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor more actively than BMSCs. To analyze the therapeutic function of DPCs in SCI, primary DPCs and BMSCs were cultured from the same green fluorescence protein-transgenic rat. The cells were suspended in rat-tail collagen I and transplanted separately into completely transected spinal cord lesion sites. Grafted-cell survival was examined with a small animal in vivo imaging detection system, and lesion sites were examined histochemically. In vivo imaging revealed enhanced lesion filling and survival with DPC grafts compared with BMSC grafts on days 14 and 21 post-transplantation. Hematoxylin and eosin staining demonstrated that lesion area sizes in the two groups were not markedly different. In the DPC transplant group, more axons formed within the lesion sites. CD31-positive vessel-like structures were more abundant in lesion sites near the grafted cells in the DPC group. The results of the present study suggest that DPCs may be a valuable alternative source of stem cells for autologous cell therapy for the treatment of SCI.

Bone marrow mesenchymal stem cells (BMSCs) improved functional recovery of spinal cord injury partly by promoting axonal regeneration

Spinal cord injury (SCI) disrupts the spinal cord and results in the loss of sensory and motor function below the lesion site. The treatment of SCI became a challenge because the injured neurons fail to axon regenerate and repair after injury. Promoting axonal regeneration plays a key role in the treatment strategies for SCI. It would meet the goal of reconstruction the injured spinal cord and improving the functional recovery. Bone marrow mesenchymal stem cells (BMSCs) are attractive therapeutic potential cell sources for SCI, and it could rebuild the injured spinal cord through neuroprotection, neural regeneration and remyelinating. Evidence has demonstrated that BMSCs play important roles in mediating axon regeneration, and glial scar formation after SCI in animal experiments and some clinical trials. We reviewed the role of BMSCs in regulating axon regeneration and glial scar formation after SCI. BMSCs based therapies may provide a therapeutic potential for the injured spinal cord by promoting axonal regeneration and repair.

Transplantation of choroid plexus epithelial cells into contusion-injured spinal cord of rats

Purpose: The effect of the transplantation of choroid plexus epithelial cells (CPECs) on locomotor improvement and tissue repair including axonal extension in spinal cord lesions was examined in rats with spinal cord injury (SCI).

Methods: CPECs were cultured from the choroid plexus of green fluorescent protein (GFP)-transgenic rats, and transplanted directly into the contusion-injured spinal cord lesions of rats of the same strain. Locomotor behaviors were evaluated based on BBB scores every week after transplantation until 4 weeks after transplantation. Histological and immunohistochemical examinations were performed at 2 days, and every week until 5 weeks after transplantation.

Results: Locomotor behaviors evaluated by the BBB score were significantly improved in cell-transplanted rats. Numerous axons grew, with occasional interactions with CPECs, through the astrocyte-devoid areas. These axons exhibited structural characteristics of peripheral nerves. GAP-43-positive axons were found at the border of the lesion 2 days after transplantation. Cavity formation was more reduced in cell-transplanted than control spinal cords. CPECs were found within the spinal cord lesion, and sometimes in association with astrocytes at the border of the lesion until 2 weeks after transplantation.

Conclusion: The transplantation of CPECs enhanced locomotor improvement and tissue recovery, including axonal regeneration, in rats with SCI.

Effects of Intrathecal Injection of the Conditioned Medium from Bone Marrow Stromal Cells on Spinal Cord Injury in Rats

Bone marrow stromal cells (BMSCs) have been studied for the treatment of spinal cord injury (SCI). In previous studies, we showed that the transplantation of BMSCs, even though they disappeared from the host spinal cord within 1-3 weeks after transplantation, improved locomotor behaviors and promoted axonal regeneration. This result led to the hypothesis that BMSCs might release some neurotrophic factors effective for the treatment of SCI. The present study examined this by injecting the conditioned medium (CM) of BMSCs to treat SCI in rats. The spinal cord was contusion-injured, followed immediately by continuous injection for 2 weeks of the CM of BMSCs through the cerebrospinal fluid via the 4th ventricle using an Alzet osmotic pump. Locomotor behaviors evaluated by the Basso-Beattie-Bresnahan score were markedly improved in the CM-injection group, compared with the control group, at 1 to 4 weeks post-injection. The contusion-injured site of the spinal cord was identified as an astrocyte-devoid area, which contained no astrocytes but was filled with collagen matrices and empty cavities of various sizes. Collagen matrices contained type I collagen and laminin. Numerous axons extended through the collagen matrices of the astrocyte-devoid area. Axons were surrounded by Schwann cells, exhibiting the same morphological characteristics as peripheral nerve fibers. The density of axons extending through the astrocyte-devoid area was higher in the CM-injection group, compared with the control group. CM injection had beneficial effects on locomotor improvements and tissue repair, including axonal regeneration, meaning that the BMSC-CM stimulated the intrinsic ability of the spinal cord to regenerate. Activation of the intrinsic ability of the spinal cord to regenerate by the injection of neurotrophic factors such as BMSC-CM is considered to be a safe and preferable method for the clinical treatment of SCI.

Priming with FGF2 stimulates human dental pulp cells to promote axonal regeneration and locomotor function recovery after spinal cord injury

Human dental pulp cells (DPCs), adherent cells derived from dental pulp tissues, are potential tools for cell transplantation therapy. However, little work has been done to optimize such transplantation. In this study, DPCs were treated with fibroblast growth factor-2 (FGF2) for 5-6 consecutive serial passages and were transplanted into the injury site immediately after complete transection of the rat spinal cord. FGF2 priming facilitated the DPCs to promote axonal regeneration and to improve locomotor function in the rat with spinal cord injury (SCI). Additional analyses revealed that FGF2 priming protected cultured DPCs from hydrogen-peroxide-induced cell death and increased the number of DPCs in the SCI rat spinal cord even 7 weeks after transplantation. The production of major neurotrophic factors was equivalent in FGF2-treated and untreated DPCs. These observations suggest that FGF2 priming might protect DPCs from the post-trauma microenvironment in which DPCs infiltrate and resident immune cells generate cytotoxic reactive oxygen species. Surviving DPCs could increase the availability of neurotrophic factors in the lesion site, thereby promoting axonal regeneration and locomotor function recovery.

Treadmill exercise with bone marrow stromal cells transplantation potentiates recovery of locomotor function after spinal cord injury in rats

Transplantation of bone marrow stromal cells (BMSCs) is regarded as a promising candidate for the spinal cord injury (SCI). In the present study, we investigated whether treadmill exercise potentiate the effect of BM-SCs transplantation on the functional recovery in the SCI rats. The spinal cord contusion injury applied at the T9–T10 level using the impactor. Cultured BMSCs were transplanted into the lesion at 1 week after SCI induction. Treadmill exercise was conducted for 6 weeks. Basso-Beattie-Bresnahan (BBB) scale for locomotor function was determined. Sprouting axons in the lesion cavity were detected by immunofluorescence staining for neurofilament-200. Brain-derived neurotrophic factor (BDNF) and synapsin-I expressions were analyzed using western blotting. BMSCs transplantation improved BBB score and increased expressions of neurofilament-200, BDNF, and synapsin-I in the SCI rats. Treadmill exercise potentiated the improving effect of BMSCs transplantation on BBB score in the SCI rats. This potentiating effect of treadmill exercise could be ascribed to the enhancement of BDNF expression in the SCI rats.

Effect of transplantation of olfactory ensheathing cell conditioned medium induced bone marrow stromal cells on rats with spinal cord injury

Spinal cord injury is a serious threat to human health and various techniques have been deployed to ameliorate or cure its effects. Stem cells transplantation is one of the promising methods. The primary aim of the present study was to investigate the effect of the transplantation of olfactory ensheathing cell (OEC) conditioned medium-induced bone marrow stromal cells (BMSCs) on spinal cord injury. Rat spinal cord compression injury animal models were generated, and the rats divided into the following three groups: Group A, (control) Dulbecco's modified Eagle's medium-treated group; group B, normal BMSC-treated group; group C, OEC conditioned medium-induced BMSC-treated group. The animals were sacrificed at 2, 4 and 8 weeks following transplantation for hematoxylin and eosin staining, and fluorescence staining of neurofilament protein, growth associated protein-43 and neuron-specific nuclear protein. The cavity area of the spinal cord injury was significantly reduced at 2 and 4 weeks following transplantation in group C, and a significant difference between the Basso, Beattie and Bresnahan score in group C and groups A and B was observed. Regenerated nerve fibers were observed in groups B and C; however, a greater number of regenerated nerve fibers were observed in group C. BMSCs induced by OEC conditioned medium survived in vivo, significantly reduced the cavity area of spinal cord injury, promoted nerve fiber regeneration following spinal cord injury and facilitated recovery of motor function. The present study demonstrated a novel method to repair spinal cord injury by using induced BMSCs, with satisfactory results.

Erythropoietin facilitates the recruitment of bone marrow mesenchymal stem cells to sites of spinal cord injury

Despite the successes of bone marrow mesenchymal stem cell (BMSC) transplantation for the treatment of spinal cord injuries, only a small fraction of grafted cells migrate to the target areas. Therefore, there remains a need for more efficient strategies of BMSC delivery. The present study was designed to explore this. Rat models of spinal cord injury (SCI) were established and exposed to phosphate buffered saline (control), BMSCs or BMSCs + erythropoietin (EPO). Basso, Beattie and Bresnahan (BBB) locomotor scale and grid walk tests were then utilized to estimate neurological rehabilitation. Additionally, the following assays were performed: Immunofluorescence localization of BMSCs to the site of SCI; the transwell migration assay to detect in vitro cellular migration; the terminal deoxynucleotidyl transferase dUTP nick end labeling assay to determine the apoptotic index of the lesion; and western blotting analysis to evaluate the expression of vascular endothelial growth factor (VEGF) and brain derived neurotrophic factor (BDNF) at the site of SCI. The BBB scores of the BMSC + EPO treated group were significantly increased compared with the BMSC treatment group (P<0.05). For example, BMSC + EPO treated rats had a significantly decreased number of hind limb slips compared with the BMSC treatment group (P<0.05). Furthermore, EPO significantly increased the migration capacity of BMSCs compared with the control group (P<0.001). In addition, the apoptotic index of the BMSC + EPO group was significantly decreased compared with the BMSC group (P<0.05). Green fluorescent protein-labeled BMSCs were detected at the site of SCI in the BMSC and BMSCs + EPO groups, with the signal being notably stronger in the latter. Moreover, the expression of VEGF and BDNF in the BMSCs + EPO group was significantly increased compared with the BMSC group (P<0.05). In conclusion, the results of the present study indicate that EPO can facilitate the recruitment of BMSCs to sites of SCI, increase expression of BDNF and VEGF, and accelerate recovery of neurological function following SCI.

Repeated subarachnoid administrations of autologous mesenchymal stromal cells supported in autologous plasma improve quality of life in patients suffering incomplete spinal cord injury

BACKGROUND AIMS

Cell therapy with mesenchymal stromal cells (MSCs) offers new hope for patients suffering from spinal cord injury (SCI).

METHODS

Ten patients with established incomplete SCI received four subarachnoid administrations of 30 × 10⁶ autologous bone marrow MSCs, supported in autologous plasma, at months 1, 4, 7 and 10 of the study, and were followed until the month 12. Urodynamic, neurophysiological and neuroimaging studies were performed at months 6 and 12, and compared with basal studies.

RESULTS

Variable improvement was found in the patients of the series. All of them showed some degree of improvement in sensitivity and motor function. Sexual function improved in two of the eight male patients. Neuropathic pain was present in four patients before treatment; it disappeared in two of them and decreased in another. Clear improvement in bladder and bowel control were found in all patients suffering previous dysfunction. Before treatment, seven patients suffered spasms, and two improved. Before cell therapy, nine patients suffered variable degree of spasticity, and 3 of them showed clear decrease at the end of follow-up. At this time, nine patients showed infra-lesional electromyographic recordings suggesting active muscle reinnervation, and eight patients showed improvement in bladder compliance. After three administrations of MSCs, mean values of brain-derived neurotrophic factor, glial-derived neurotrophic factor, ciliary neurotrophic factor, and neurotrophin 3 and 4 showed slight increases compared with basal levels, but without statistically significant difference.

CONCLUSIONS

Administration of repeated doses of MSCs by subarachnoid route is a well-tolerated procedure that is able to achieve progressive and significant improvement in the quality of life of patients suffering incomplete SCI.

Functional Recovery from Neural Stem/Progenitor Cell Transplantation Combined with Treadmill Training in Mice with Chronic Spinal Cord Injury

Most studies targeting chronic spinal cord injury (SCI) have concluded that neural stem/progenitor cell (NS/PC) transplantation exerts only a subclinical recovery; this in contrast to its remarkable effect on acute and subacute SCI. To determine whether the addition of rehabilitative intervention enhances the effect of NS/PC transplantation for chronic SCI, we used thoracic SCI mouse models to compare manifestations secondary to both transplantation and treadmill training, and the two therapies combined, with a control group. Significant locomotor recovery in comparison with the control group was only achieved in the combined therapy group. Further investigation revealed that NS/PC transplantation improved spinal conductivity and central pattern generator activity, and that treadmill training promoted the appropriate inhibitory motor control. The combined therapy enhanced these independent effects of each single therapy, and facilitated neuronal differentiation of transplanted cells and maturation of central pattern generator activity synergistically. Our data suggest that rehabilitative treatment represents a therapeutic option for locomotor recovery after NS/PC transplantation, even in chronic SCI.

An approach to personalized cell therapy in chronic complete paraplegia: The Puerta de Hierro phase I/II clinical trial

BACKGROUND AIMS

Cell transplantation in patients suffering spinal cord injury (SCI) is in its initial stages, but currently there is confusion about the results because of the disparity in the techniques used, the route of administration, and the criteria for selecting patients.

METHODS

We conducted a clinical trial involving 12 patients with complete and chronic paraplegia (average time of chronicity, 13.86 years; SD, 9.36). The characteristics of SCI in magnetic resonance imaging (MRI) were evaluated for a personalized local administration of expanded autologous bone marrow mesenchymal stromal cells (MSCs) supported in autologous plasma, with the number of MSCs ranging from 100 × 10(6) to 230 × 10(6). An additional 30 × 10(6) MSCs were administered 3 months later by lumbar puncture into the subarachnoid space. Outcomes were evaluated at 3, 6, 9 and 12 months after surgery through clinical, urodynamic, neurophysiological and neuroimaging studies.

RESULTS

Cell transplantation is a safe procedure. All patients experienced improvement, primarily in sensitivity and sphincter control. Infralesional motor activity, according to clinical and neurophysiological studies, was obtained by more than 50% of the patients. Decreases in spasms and spasticity, and improved sexual function were also common findings. Clinical improvement seems to be dose-dependent but was not influenced by the chronicity of the SCI.

CONCLUSION

Personalized cell therapy with MSCs is safe and leads to clear improvements in clinical aspects and quality of life for patients with complete and chronically established paraplegia.

The role of the PI3K/Akt/mTOR pathway in glial scar formation following spinal cord injury

Several studies suggest that glial scars pose as physical and chemical barriers that limit neurite regeneration after spinal cord injury (SCI). Evidences suggest that the activation of the PI3K/Akt/mTOR signaling pathway is involved in glial scar formation. Therefore, inhibition of the PI3K/Akt/mTOR pathway may beneficially attenuate glial scar formation after SCI. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) negatively regulates the PI3K/Akt/mTOR pathway. Therefore, we hypothesized that the overexpression of PTEN in the spinal cord will have beneficial effects after SCI. In the present study, we intrathecally injected a recombinant adenovirus carrying the pten gene (Ad-PTEN) to cause overexpression of PTEN in rats with contusion injured spinal cords. The results suggest overexpression of PTEN in spinal cord attenuated glial scar formation and led to improved locomotor function after SCI. Overexpression of PTEN following SCI attenuated gliosis, affected chondroitin sulfate proteoglycan expression, and improved axon regeneration into the lesion site. Furthermore, we suggest that the activation of the PI3K/Akt/mTOR pathway in astrocytes at 3 days after SCI may be involved in glial scar formation. Because delayed treatment with Ad-PTEN enhanced motor function recovery more significantly than immediate treatment with Ad-PTEN after SCI, the results suggest that the best strategy to attenuate glial scar formation could be to introduce 3 days after SCI. This study's findings thus have positive implications for patients who are unable to receive immediate medical attention after SCI.

Cell transplantation for the treatment of spinal cord injury - bone marrow stromal cells and choroid plexus epithelial cells

Transplantation of bone marrow stromal cells (BMSCs) enhanced the outgrowth of regenerating axons and promoted locomotor improvements of rats with spinal cord injury (SCI). BMSCs did not survive long-term, disappearing from the spinal cord within 2–3 weeks after transplantation. Astrocyte-devoid areas, in which no astrocytes or oligodendrocytes were found, formed at the epicenter of the lesion. It was remarkable that numerous regenerating axons extended through such astrocyte-devoid areas. Regenerating axons were associated with Schwann cells embedded in extracellular matrices. Transplantation of choroid plexus epithelial cells (CPECs) also enhanced axonal regeneration and locomotor improvements in rats with SCI. Although CPECs disappeared from the spinal cord shortly after transplantation, an extensive outgrowth of regenerating axons occurred through astrocyte-devoid areas, as in the case of BMSC transplantation. These findings suggest that BMSCs and CPECs secret neurotrophic factors that promote tissue repair of the spinal cord, including axonal regeneration and reduced cavity formation. This means that transplantation of BMSCs and CPECs promotes “intrinsic” ability of the spinal cord to regenerate. The treatment to stimulate the intrinsic regeneration ability of the spinal cord is the safest method of clinical application for SCI. It should be emphasized that the generally anticipated long-term survival, proliferation and differentiation of transplanted cells are not necessarily desirable from the clinical point of view of safety.

Locomotor improvement of spinal cord-injured rats through treadmill training by forced plantar placement of hind paws

STUDY DESIGN

Experimental training model of rats with spinal cord injury (SCI).

SETTING

Osaka, JapanObjective:To investigate the effect of forced treadmill training by plantar placement (PP), as compared with dorsal placement (DP), of the dorsal paws on the locomotor behaviors of spinal cord-injured rats.

METHODS

The spinal cord was contusion-injured at the thoracic level. Rats were divided into three groups: forced training involving stepping by PP and DP and non-forced training/assistance (nT). Training began 1 week after injury and was conducted for 4 weeks. Locomotor behaviors were estimated using Basso-Beattie-Bresnahan (BBB) scores, dorsiflexion of the hind paws and footprints of the hind paws. Histological and immunohistochemical examinations of the spinal cord lesions were conducted after 4 weeks of training.

RESULTS

The values, respectively, of PP, DP and nT groups at 4 weeks of training were as follows: BBB scores were 15.6±0.8, 7.7±1.3 and 10.3±0.4. The paw dorsiflexion angles were 34.1±5.2, 16.4±2.4 and 23.6±3.0 degrees, respectively. The stride angles were 5.1±0.9, 13.7±4.9 and 17.8±4.0 degrees for the left paws. Cavity volumes were 10.3±2.1, 31.0±2.0 and 28.2±4.9%. In addition to cavities, there were astrocyte-devoid areas containing some loose tissues, through which many axons extended longitudinally.

CONCLUSIONS

The BBB score, dorsiflexion angle and stride angle were consistently improved in the PP group. Cavity formation was more reduced, and many axons extended through coarse tissues formed in astrocyte-devoid areas at the lesion in the PP group. Forced training by PP of the hind paws promoted the behavioral and histological improvement of rats with SCI.

Intranasal delivery of bone marrow stromal cells to spinal cord lesions

OBJECT

The intranasal delivery of bone marrow stromal cells (BMSCs) or mesenchymal stem cells to the injured brains of rodents has been previously reported. In this study, the authors investigated whether BMSCs migrate to spinal cord lesions through an intranasal route and whether the administration affected functional recovery.

METHODS

Forty Sprague-Dawley rats that were subjected to spinal cord injuries at the T7–8 level were divided into 5 groups (injured + intranasal BMSC–treated group, injured + intrathecal BMSC–treated group, injured-only group, injured + intranasal vehicle–treated group, and injured + intrathecal vehicle–treated group). The Basso-Beattie-Bresnahan (BBB) scale was used to assess hind limb motor functional recovery for 2 or 4 weeks. Intralesionally migrated BMSCs were examined histologically and counted at 2 and 4 weeks. To evaluate the neuroprotective and trophic effects of BMSCs, the relative volume of the lesion cavity was measured at 4 weeks. In addition, nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) levels in the CSF were evaluated at 2 weeks.

RESULTS

Intranasally administered BMSCs were confirmed within spinal cord sections at both 2 and 4 weeks. The highest number, which was detected in the intrathecal BMSC–treated group at 2 weeks, was significantly higher than that in all the other groups. The BBB score of the intranasal BMSC–treated group showed statistically significant improvements by 1 week compared with the control group. However, in the final BBB scores, there was a statistically significant difference only between the intrathecal BMSC–treated group and the control group. The cavity ratios in the BMSC-treated groups were smaller than those of the control groups, but the authors did not find any significant differences in the NGF and BDNF levels in the CSF among the treatment and control groups.

CONCLUSIONS

BMSCs reached the injured spinal cord through the intranasal route and contributed to the recovery of hind limb motor function and lesion cavity reduction. However, the effects were not as significant as those seen in the intrathecal BMSC–treated group.

Chronic spinal cord injury treated with transplanted autologous bone marrow-derived mesenchymal stem cells tracked by magnetic resonance imaging: a case report

INTRODUCTION

Intrathecal transplantation is a minimally invasive method for the delivery of stem cells, however, whether the cells migrate from the lumbar to the injured cervical spinal cord has not been proved in humans. We describe an attempt to track bone marrow-derived mesenchymal stem cells in a patient with a chronic cervical spinal cord injury.

CASE PRESENTATION

A 33-year-old Thai man who sustained an incomplete spinal cord injury from the atlanto-axial subluxation was enrolled into a pilot study aiming to track bone marrow-derived mesenchymal stem cells, labeled with superparamagnetic iron oxide nanoparticles, from intrathecal transplantation in chronic cervical spinal cord injury. He had been dependent on respiratory support since 2005. There had been no improvement in his neurological function for the past 54 months. Bone marrow-derived mesenchymal stem cells were retrieved from his iliac crest and repopulated to the target number. One half of the total cells were labeled with superparamagnetic iron oxide nanoparticles before transplantation to the intrathecal space between L4 and L5. Magnetic resonance imaging studies were performed immediately after the transplantation and at 48 hours, two weeks, one month and seven months after the transplantation. His magnetic resonance imaging scan performed immediately after the transplantation showed hyposignal intensity of paramagnetic substance tagged stem cells in the subarachnoid space at the lumbar spine area. This phenomenon was observed at the surface around his cervical spinal cord at 48 hours. A focal hyposignal intensity of tagged bone marrow-derived stem cells was detected at his cervical spinal cord with magnetic resonance imaging at 48 hours, which faded after two weeks, and then disappeared after one month. No clinical improvement of the neurological function had occurred at the end of this study. However, at 48 hours after the transplantation, he presented with a fever, headache, myalgia and worsening of his motor function (by one grade of all key muscles by the American Spinal Injury Association impairment scale), which lasted for 48 hours.

CONCLUSION

Intrathecal injection of bone marrow-derived stem cells at the lumbar spine level could deliver the cells to the injured cervical spinal cord. Transient complications should be observed closely in the first 48 hours after transplantation. Further study should be carried out to evaluate the result of the treatment.

Diffuse and persistent blood-spinal cord barrier disruption after contusive spinal cord injury rapidly recovers following intravenous infusion of bone marrow mesenchymal stem cells

Intravenous infusion of mesenchymal stem cells (MSCs) has been shown to reduce the severity of experimental spinal cord injury (SCI), but mechanisms are not fully understood. One important consequence of SCI is damage to the microvasculature and disruption of the blood spinal cord barrier (BSCB). In the present study we induced a contusive SCI at T9 in the rat and studied the effects of intravenous MSC infusion on BSCB permeability, microvascular architecture and locomotor recovery over a 10week period. Intravenously delivered MSCs could not be identified in the spinal cord, but distributed primarily to the lungs where they survived for a couple of days. Spatial and temporal changes in BSCB integrity were assessed by intravenous infusions of Evans blue (EvB) with in vivo and ex vivo optical imaging and spectrophotometric quantitation of EvB leakage into the parenchyma. SCI resulted in prolonged BSCB leakage that was most severe at the impact site but disseminated extensively rostral and caudal to the lesion over 6weeks. Contused spinal cords also showed an increase in vessel size, reduced vessel number, dissociation of pericytes from microvessels and decreases in von Willebrand factor (vWF) and endothelial barrier antigen (EBA) expression. In MSC-treated rats, BSCB leakage was reduced, vWF expression was increased and locomotor function improved beginning 1 week post-MSC infusion, i.e., 2weeks post-SCI. These results suggest that intravenously delivered MSCs have important effects on reducing BSCB leakage which could contribute to their therapeutic efficacy.

Lithium enhanced cell proliferation and differentiation of mesenchymal stem cells to neural cells in rat spinal cord

Lithium has been shown to inhibit apoptosis of neural progenitor cells (NPCs) and promote differentiation of NPCs. However, there was rare data to discuss the effects of lithium on neural differentiation of mesenchymal stem cells (MSCs). Here, we investigated the potential promotion of lithium to MSC proliferation and neural differentiation in vitro and after transplanted into the ventral horn of rat spinal cord in vivo. We found that lithium possesses the ability to promote proliferation of GFP-MSCs in a dose dependent manner as verified by growth curve and bromodeoxyuridine (BrdU) incorporation assays; While in neural induction medium, lithium (0.1 mM) promotes neural differentiation of GFP-MSCs as verified by immunostaining and quantitative analysis. After transplantation of GFP-MSCs into the rat spinal cord, lithium treatment enhanced cell survival and neural differentiation after transplantation as verified by immunohistochemistry. These data suggested that lithium could be a potential drug to augment the therapeutic efficiency of MSCs transplantation therapy in central nervous system (CNS) disorders.

A nutrient mixture reduces the expression of matrix metalloproteinases in an animal model of spinal cord injury by modulating matrix metalloproteinase-2 and matrix metalloproteinase-9 promoter activities

This study aimed to determine whether a novel nutrient mixture (NM), composed of lysine, ascorbic acid, proline, green tea extracts and other micronutrients, attenuates impairments induced by spinal cord injury (SCI) and to investigate the related molecular mechanisms. A mouse model of SCI was established. Thirty-two mice were divided into four groups. The sham group received vehicle only. The SCI groups were treated orally with saline (saline group), a low dose (500 μg 3 times/day) of NM (NM-LD group) or a high dose (2,000 μg 3 times/day) of NM (NM-HD group). The levels of mouse hindlimb movement were determined every day in the first week post-surgery. The protein expression levels of matrix metalloproteinase (MMP)-2 and MMP-9 were determined by western blotting. Wild-type and mutant MMP-2- and MMP-9-directed luciferase constructs were generated and their luciferase activities were determined. NM significantly facilitated the recovery of hindlimb movement of the mice in comparison to that in the saline group. The expression levels of MMP-2 in the NM-LD and NM-HD groups were decreased by ~50% compared with the saline group as indicated by western blotting results. The expression levels of MMP-9 in the NM-LD and NM-HD groups were decreased to ~25 and ~10%, respectively. These results suggest that NM significantly inhibits the expression of MMP-2 and MMP-9 proteins. Reverse transcription quantitative polymerase chain reaction results indicated that NM reduced the levels of MMP-2 and MMP-9 mRNA. Furthermore, the luciferase results indicated that site-directed mutagenesis comprising a −1306 C to T (C/T) base change in the MMP-2 promoter and a −1562 C/T base change in the MMP-9 promoter abolished the inhibitory effects of NM on MMP-2 and MMP-9 promoters. These results suggest that NM attenuates SCI-induced impairments in mice movement by negatively affecting the promoter activity of MMP-2 and MMP-9 genes and thus decreasing the expression of MMP-2 and MMP-9 proteins.