Stem cell transplantation in traumatic spinal cord injury: a systematic review and meta-analysis of animal studies

Influential factors on stem cell therapy success in canine model of spinal cord Injury: A systematic review and meta-analysis

Spinal cord injury (SCI) is a serious medical condition. The search for an effective cure remains a persistent challenge. Current treatments, unfortunately, are unable to sufficiently improve neurological function, often leading to lifelong disability. This systematic review and meta-analysis evaluated the effectiveness of stem cell therapy for SCI using canine models. It also explored the optimal protocol for implementing stem cell therapy. A comprehensive search of studies was conducted from 2000 to October 2022. This study focused on five outcomes: motor function score, histopathology, IHC, western blot, and SEP. The results demonstrated a significant improvement in locomotion post-SCI in dogs treated with stem cell therapy. The therapy also led to an average increase of 3.15 points in the Olby score of the treated dogs compared to the control group. These findings highlights stem cell therapy's potential as a promising SCI treatment. The meta-analysis suggests that using bone marrow stem cells, undergoing neural differentiation in vitro, applying a surgical implantation or intrathecal route of administration, associating matrigel in combination with stem cells, and a waiting period of two weeks before starting treatment can enhance SCI treatment effectiveness.

Stem Cells in the Treatment of Spinal Cord Injury: A Review of Currently Registered Clinical Trials

BACKGROUND

Spinal cord injury (SCI) affects around 18,000 individuals annually, representing nearly one-third of all paralysis cases. Stem cell therapy, a focal point in contemporary neuroregeneration research for SCI treatment, holds potential in leveraging undifferentiated stem cells to regenerate damaged tissues. This study seeks to comprehensively analyze current clinical trials exploring the potential use of stem cells in treating spinal cord injuries.

METHODS

A data retrieval approach examined the ClinicalTrials.gov database using the terms "spinal cord injury" and "stem cells." Exclusion criteria eliminated studies not recruiting, terminated prematurely, suspended, withdrawn, or of unknown status. Data for each trial, including ClinicalTrial.gov NCT identifier, title, intervention details, initiation/completion dates, and sample size, were systematically collected. Literature searches on PubMed.gov were conducted for completed trials with results.

RESULTS

Thirty clinical trials were analyzed, with 20 completed and six with published results on PubMed.gov. Interventions included 20 biological (66.7%), 6 procedural (20%), and 4 drug interventions (13.3%). Stem cell sources varied, including bone marrow (46.7%), umbilical cells (20%), adipose tissue (20%), embryonic cells (6.7%), and neural cells (6.7%). Trials spanned 2005 to 2022, with 11 (36.7%) commencing in or after 2017. Among six trials with results, 50% used bone marrow-derived stem cells.

CONCLUSIONS

The promising potential of stem cells in neuroregenerative SCI treatment necessitates further exploration through large-scale, multicenter clinical trials to enhance understanding and guide wider adoption of this emerging treatment paradigm.

Effect-Size Discrepancies in Literature Versus Raw Datasets from Experimental Spinal Cord Injury Studies: A CLIMBER Meta-Analysis

Translation of spinal cord injury (SCI) therapeutics from pre-clinical animal studies into human studies is challenged by effect size variability, irreproducibility, and misalignment of evidence used by pre-clinical versus clinical literature. Clinical literature values reproducibility, with the highest grade evidence (class 1) consisting of meta-analysis demonstrating large therapeutic efficacy replicating across multiple studies. Conversely, pre-clinical literature values novelty over replication and lacks rigorous meta-analyses to assess reproducibility of effect sizes across multiple articles. Here, we applied modified clinical meta-analysis methods to pre-clinical studies, comparing effect sizes extracted from published literature to raw data on individual animals from these same studies. Literature-extracted data (LED) from numerical and graphical outcomes reported in publications were compared with individual animal data (IAD) deposited in a federally supported repository of SCI data. The animal groups from the IAD were matched with the same cohorts in the LED for a direct comparison. We applied random-effects meta-analysis to evaluate predictors of neuroconversion in LED versus IAD. We included publications with common injury models (contusive injuries) and standardized end-points (open field assessments). The extraction of data from 25 published articles yielded n = 1841 subjects, whereas IAD from these same articles included n = 2441 subjects. We observed differences in the number of experimental groups and animals per group, insufficient reporting of dropout animals, and missing information on experimental details. Meta-analysis revealed differences in effect sizes across LED versus IAD stratifications, for instance, severe injuries had the largest effect size in LED (standardized mean difference [SMD = 4.92]), but mild injuries had the largest effect size in IAD (SMD = 6.06). Publications with smaller sample sizes yielded larger effect sizes, while studies with larger sample sizes had smaller effects. The results demonstrate the feasibility of combining IAD analysis with traditional LED meta-analysis to assess effect size reproducibility in SCI.

The Efficacy of Different Material Scaffold-Guided Cell Transplantation in the Treatment of Spinal Cord Injury in Rats: A Systematic Review and Network Meta-analysis

Cell transplantation is a promising treatment option for spinal cord injury (SCI). However, there is no consensus on the choice of carrier scaffolds to host the cells. This study aims to evaluate the efficacy of different material scaffold-mediated cell transplantation in treating SCI in rats. According to PRISMA's principle, Embase, PubMed, Web of Science, and Cochrane databases were searched, and relevant literature was referenced. Only original research on cell transplantation plus natural or synthetic scaffolds in SCI rats was included. Direct and indirect evidence for improving hind limb motor function was pooled through meta-analysis. A subgroup analysis of some factors that may affect the therapeutic effect was conducted to understand the results fully. In total, 25 studies met the inclusion criteria, in which 293 rats received sham surgery, 78 rats received synthetic material scaffolds, and 219 rats received natural materials scaffolds. The network meta-analysis demonstrated that although synthetic scaffolds were slightly inferior to natural scaffolds in terms of restoring motor function in cell transplantation of SCI rats, no statistical differences were observed between the two (MD: -0.35; 95% CI -2.6 to 1.9). Moreover, the subgroup analysis revealed that the type and number of cells may be important factors in therapeutic efficacy (P < 0.01). Natural scaffolds and synthetic scaffolds are equally effective in cell transplantation of SCI rats without significant differences. In the future, the findings need to be validated in multicenter, large-scale, randomized controlled trials in clinical practice. Trial registration: Registration ID CRD42024459674 (PROSPERO).

The application of stem cell sheets for neuronal regeneration after spinal cord injury: a systematic review of pre-clinical studies

BACKGROUND

Stem cell sheet implantation offers a promising avenue for spinal cord injury (SCI) and is currently under investigation in pre-clinical in vivo studies. Nevertheless, a systematic review of the relevant literature is yet to be performed. Thus, this systematic review aims to explore the efficacy of stem cell sheet technology in treating SCI, as indicated by experimental animal model studies.

METHODS

We searched PubMed, EMBASE, and Web of Science. Manuscripts that did not pertain to in vivo pre-clinical studies and those published in non-English languages were excluded. A risk assessment for bias was performed using the SYRCLE tool. Extracted data were synthesized only qualitatively because the data were not suitable for conducting the meta-analysis.

RESULTS

Among the 847 studies retrieved from electronic database searches, seven met the inclusion criteria. Six of these studies employed a complete transection model, while one utilized a compression model. Stem cell sources included bone marrow mesenchymal stem cells, stem cells from human exfoliated deciduous teeth, and adipose-derived mesenchymal stem cells. In all included studies, stem cell sheet application significantly improved motor and sensory functional scores compared to intreated SCI rats. This functional recovery correlated with histological improvements at the injury site. All studies are at low risk of bias but certain domains were not reported by some or all of the studies.

CONCLUSION

The results of our systematic review suggest that stem cell sheets may be a feasible therapeutic approach for the treatment of SCI. Future research should be conducted on stem cell sheets in various animal models and types of SCI, and careful validation is necessary before translating stem cell sheets into clinical studies.

The Role of Mesenchymal Stromal Cells and Their Products in the Treatment of Injured Spinal Cords

Spinal cord injury (SCI) is a destructive condition that results in lasting neurological damage resulting in disruption of the connection between the central nervous system and the rest of the body. Currently, there are several approaches in the treatment of a damaged spinal cord; however, none of the methods allow the patient to return to the original full-featured state of life before the injury. Cell transplantation therapies show great potential in the treatment of damaged spinal cords. The most examined type of cells used in SCI research are mesenchymal stromal cells (MSCs). These cells are at the center of interest of scientists because of their unique properties. MSCs regenerate the injured tissue in two ways: (i) they are able to differentiate into some types of cells and so can replace the cells of injured tissue and (ii) they regenerate tissue through their powerful known paracrine effect. This review presents information about SCI and the treatments usually used, aiming at cell therapy using MSCs and their products, among which active biomolecules and extracellular vesicles predominate.

Motor functional recovery efficacy of scaffolds with bone marrow stem cells in rat spinal cord injury: a Bayesian network meta-analysis

STUDY DESIGN

A Bayesian network meta-analysis.

OBJECTIVE

Spinal cord injury (SCI) can profoundly influence human health and has been linked to lifelong disability. More high-level evidence-based medical research is expected to evaluate the value of stem cells and biomaterial scaffold material therapy for SCI.

METHODS

We performed a comprehensive search of Web of Science, Cochrane databases, Embase, and PubMed databases. 18 randomized controlled trials including both scaffolds and BMSCs were included. We performed a Bayesian network meta-analysis to compare the motor functional recovery efficacy of different scaffolds with BMSCs in rat SCI.

RESULTS

In our Bayesian network meta-analysis, the motor functional recovery was found to benefit from scaffolds, BMSCs, and BMSCs combined with scaffolds, but the scaffold and BMSC groups had similar motor functional recovery efficacy, and the BMSCs combined with scaffolds group appeared to show better efficacy than BMSCs and scaffolds alone. Subgroup analysis showed that BMSCs+fibrin, BMSCs+ASC, BMSCs+gelatine, and BMSCs+collagen were the best four treatments for SCI in rat models.

CONCLUSIONS

These Bayesian network meta-analysis findings strongly indicated that BMSCs combined with scaffolds is more effective to improve motor functional recovery than BMSCs and scaffolds alone. The fibrin, gelatine, ASC, and collagen may be favourable scaffolds for the injured spinal cord and that scaffolds with BMSCs could be a promising option in regeneration therapy for patients with SCI.

Rassf7a promotes spinal cord regeneration and controls spindle orientation in neural progenitor cells

Spinal cord injury (SCI) can cause long-lasting disability in mammals due to the lack of axonal regrowth together with the inability to reinitiate spinal neurogenesis at the injury site. Deciphering the mechanisms that regulate the proliferation and differentiation of neural progenitor cells is critical for understanding spinal neurogenesis after injury. Compared with mammals, zebrafish show a remarkable capability of spinal cord regeneration. Here, we show that Rassf7a, a member of the Ras-association domain family, promotes spinal cord regeneration after injury. Zebrafish larvae harboring a rassf7a mutation show spinal cord regeneration and spinal neurogenesis defects. Live imaging shows abnormal asymmetric neurogenic divisions and spindle orientation defects in mutant neural progenitor cells. In line with this, the expression of rassf7a is enriched in neural progenitor cells. Subcellular analysis shows that Rassf7a localizes to the centrosome and is essential for cell cycle progression. Our data indicate a role for Rassf7a in modulating spindle orientation and the proliferation of neural progenitor cells after spinal cord injury.

In vitro atlas of dorsal spinal interneurons reveals Wnt signaling as a critical regulator of progenitor expansion

Restoring sensation after injury or disease requires a reproducible method for generating large quantities of bona fide somatosensory interneurons. Toward this goal, we assess the mechanisms by which dorsal spinal interneurons (dIs; dI1-dI6) can be derived from mouse embryonic stem cells (mESCs). Using two developmentally relevant growth factors, retinoic acid (RA) and bone morphogenetic protein (BMP) 4, we recapitulate the complete in vivo program of dI differentiation through a neuromesodermal intermediate. Transcriptional profiling reveals that mESC-derived dIs strikingly resemble endogenous dIs, with the correct molecular and functional signatures. We further demonstrate that RA specifies dI4-dI6 fates through a default multipotential state, while the addition of BMP4 induces dI1-dI3 fates and activates Wnt signaling to enhance progenitor proliferation. Constitutively activating Wnt signaling permits the dramatic expansion of neural progenitor cultures. These cultures retain the capacity to differentiate into diverse populations of dIs, thereby providing a method of increasing neuronal yield.

Efficacy of Chinese herbal medicine for tPA thrombolysis in experimental stroke: A systematic review and meta-analysis

BACKGROUND

Tissue-type plasminogen activator (tPA) remains the sole FDA approved thrombolytic drug for ischemic stroke. But delayed thrombolytic therapy with tPA may increase the risk of hemorrhagic transformation. Many Chinese herbal medicines have been used as tPA helpers to enhance the capacity of tPA and minimize the risk of hemorrhagic transformation. The efficacy of Chinese herbal medicines on tPA thrombolysis is not systematically analyzed.

METHODS

We searched the following three databases up to January 2022: Web of Science, PubMed, and Scopus. Studies that reported the efficacy and safety of Chinese herbal medicines on tPA thrombolysis in experimental stroke were included. The efficacy outcomes were neurological score and infarct volume, the safety outcomes were cerebral hemorrhage and blood brain barrier (BBB) damage. We used the checklist of CAMARADES to assess the quality of included studies. Standardized mean difference (SMD) with 95% confidence intervals were used to assess all the outcomes. Subgroup analyses were performed to explore the sources of heterogeneity. Trim and fill method and Egger's test were used to assess the potential publication bias. Sensitivity analyses were used to identify the stability of the results.

RESULTS

A total of nine studies including 11 Chinese herbal medicines fulfilled the inclusion criteria and were subsequently analyzed. The pooled data demonstrated that Chinese herbal medicines improved neurological score (2.23 SMD, 1.42-3.04), infarct volume (1.08 SMD, 0.62-1.54), attenuated cerebral hemorrhage (1.87 SMD, 1.34-2.4), and BBB dysfunction (1.9 SMD, 1.35-2.45) following tPA thrombolysis in experimental stroke. Subgroup analysis indicated that the route of drug delivery, dosage of tPA, and stroke model used may be factors inducing heterogeneity and influencing the efficacy.

CONCLUSION

Treatment with Chinese herbal medicines significantly improved neurological score and infarct volume, reduced cerebral hemorrhage and BBB damage after tPA thrombolysis. This study supports Chinese herbal medicine as an adjuvant therapy in reducing the side effects of tPA thrombolysis after acute ischemic stroke. The results should be interpreted with more caution since this article was based on animal studies.

Effectiveness of biomaterial-based combination strategies for spinal cord repair – a systematic review and meta-analysis of preclinical literature

Study design

Systematic review and meta-analysis of preclinical literature.

Objectives

To assess the effects of biomaterial-based combination (BMC) strategies for the treatment of Spinal Cord Injury (SCI), the effects of individual biomaterials in the context of BMC strategies, and the factors influencing their efficacy. To assess the effects of different preclinical testing paradigms in BMC strategies.

Methods

We performed a systematic literature search of Embase, Web of Science and PubMed. All controlled preclinical studies describing an in vivo or in vitro model of SCI that tested a biomaterial in combination with at least one other regenerative strategy (cells, drugs, or both) were included. Two review authors conducted the study selection independently, extracted study characteristics independently and assessed study quality using a modified CAMARADES checklist. Effect size measures were combined using random-effects models and heterogeneity was explored using meta-regression with tau2, I2 and R2 statistics. We tested for small-study effects using funnel plot–based methods.

Results

134 publications were included, testing over 100 different BMC strategies. Overall, treatment with BMC therapies improved locomotor recovery by 25.3% (95% CI, 20.3–30.3; n = 102) and in vivo axonal regeneration by 1.6 SD (95% CI 1.2–2 SD; n = 117) in comparison with injury only controls.

Conclusion

BMC strategies improve locomotor outcomes after experimental SCI. Our comprehensive study highlights gaps in current knowledge and provides a foundation for the design of future experiments.

Combined meta-analysis of preclinical cell therapy studies shows overlapping effect modifiers for multiple diseases

Introduction

Cell therapy has been studied in many different research domains. Cellular replacement of damaged solid tissues is at an early stage of development, with much still to be understood. Systematic reviews and meta-analyses are widely used to aggregate data and find important patterns of results within research domains.

We set out to find common biological denominators affecting efficacy in preclinical cell therapy studies for renal, neurological and cardiac disease.

Methods

We used datasets of five previously published meta-analyses investigating cell therapy in preclinical models of chronic kidney disease, spinal cord injury, stroke and ischaemic heart disease. We transformed primary outcomes to ratios of means to permit direct comparison across disease areas. Prespecified variables of interest were species, immunosuppression, cell type, cell origin, dose, delivery and timing of the cell therapy.

Results

The five datasets from 506 publications yielded data from 13 638 animals. Animal size affects therapeutic efficacy in an inverse manner. Cell type influenced efficacy in multiple datasets differently, with no clear trend for specific cell types being superior. Immunosuppression showed a negative effect in spinal cord injury and a positive effect in cardiac ischaemic models. There was a dose–dependent relationship across the different models. Pretreatment seems to be superior compared with administration after the onset of disease.

Conclusions

Preclinical cell therapy studies are affected by multiple variables, including species, immunosuppression, dose and treatment timing. These data are important when designing preclinical studies before commencing clinical trials.

iPSC toolbox for understanding and repairing disrupted brain circuits in autism

Over the past decade, tremendous progress has been made in defining autism spectrum disorder (ASD) as a disorder of brain connectivity. Indeed, whole-brain imaging studies revealed altered connectivity in the brains of individuals with ASD, and genetic studies identified rare ASD-associated mutations in genes that regulate synaptic development and function. However, it remains unclear how specific mutations alter the development of neuronal connections in different brain regions and whether altered connections can be restored therapeutically. The main challenge is the lack of preclinical models that recapitulate important aspects of human development for studying connectivity. Through recent technological innovations, it is now possible to generate patient- or mutation-specific human neurons or organoids from induced pluripotent stem cells (iPSCs) and to study altered connectivity in vitro or in vivo upon xenotransplantation into an intact rodent brain. Here, we discuss how deficits in neurodevelopmental processes may lead to abnormal brain connectivity and how iPSC-based models can be used to identify abnormal connections and to gain insights into underlying cellular and molecular mechanisms to develop novel therapeutics.

CD200 -dependent and -independent immune-modulatory functions of neural stem cells

Neural stem/precursor cells (NPC) exhibit powerful immune-modulatory properties. Attenuation of neuroinflammation by intra-cerebroventricular transplantation of NPC, protects from immune-mediated demyelination and axonal injury. The immune modulatory properties of NPC are mediated by a non-species-specific, multiple bystander effect, mediated by both direct cell-cell contact, and by soluble factor(s). CD200 is a cell-surface molecule, with important roles in regulating diverse immune responses, and shown also to limit neuroinflammatory processes. We hypothesized that CD200 may play a role in mediating immune-modulatory effects of NPC. We used wild type and CD200-deficient NPC to examine the role of CD200 in mediating two vital aspects of NPC -immune modulatory properties: (1) Attenuation of autoimmune neuroinflammation; and (2) Suppression of immune rejection response towards transplanted allogeneic NPC from the host CNS. We found that CD200 is dispensable for attenuating acute experimental autoimmune neuroinflammation, but is required for protecting transplanted allogeneic NPC from immune rejection by the host tissue. CD200 deficient NPC showed similar growth, differentiation and survival properties as wild type NPC. CD200-deficient NPC attenuated efficiently T cell activation and proliferation, but exhibited reduced ability to inhibit macrophages. We conclude that CD200 plays a partial role in mediating the immune-modulatory properties of NPC. The differential effect on T cells versus macrophages may underlie the observed discrepancy in their function in vivo.

Optimizing Olfactory Ensheathing Cell Transplantation for Spinal Cord Injury Repair

Cell transplantation constitutes an important avenue for development of new treatments for spinal cord injury (SCI). These therapies are aimed at supporting neural repair and/or replacing lost cells at the injury site. To date, various cell types have been trialed, with most studies focusing on different types of stem cells or glial cells. Here, we review commonly used cell transplantation approaches for spinal cord injury (SCI) repair, with focus on transplantation of olfactory ensheathing cells (OECs), the glial cells of the primary olfactory nervous system. OECs are promising candidates for promotion of neural repair given that they support continuous regeneration of the olfactory nerve that occurs throughout life. Further, OECs can be accessed from the nasal mucosa (olfactory neuroepithelium) at the roof of the nasal cavity and can be autologously transplanted. OEC transplantation has been trialed in many animal models of SCI, as well as in human clinical trials. While several studies have been promising, outcomes are variable and the method needs improvement to enhance aspects such as cell survival, integration, and migration. As a case study, we include the approaches used by our team (the Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Nathan, QLD, Australia) to address the current problems with OEC transplantation and discuss how the therapeutic potential of OEC transplantation can be improved. Our approach includes discovery research to improve our knowledge of OEC biology, identifying natural and synthetic compounds to stimulate the neural repair properties of OECs, and designing three-dimensional cell constructs to create stable and transplantable cell structures.

Efficacy of adipose tissue-derived stem cells in locomotion recovery after spinal cord injury: a systematic review and meta-analysis on animal studies

BACKGROUND

Considerable disparities exist on the use of adipose tissue-derived stem cells (ADSCs) for treatment of spinal cord injury (SCI). Hence, the current systematic review aimed to investigate the efficacy of ADSCs in locomotion recovery following SCI in animal models.

METHODS

A search was conducted in electronic databases of MEDLINE, Embase, Scopus, and Web of Science until the end of July 2019. Reference and citation tracking and searching Google and Google Scholar search engines were performed to achieve more studies. Animal studies conducted on rats having SCI which were treated with ADSCs were included in the study. Exclusion criteria were lacking a non-treated control group, not evaluating locomotion, non-rat studies, not reporting the number of transplanted cells, not reporting isolation and preparation methods of stem cells, review articles, combination therapy, use of genetically modified ADSCs, use of induced pluripotent ADSCs, and human trials. Risk of bias was assessed using Hasannejad et al.'s proposed method for quality control of SCI-animal studies. Data were analyzed in STATA 14.0 software, and based on a random effect model, pooled standardized mean difference with a 95% confidence interval was presented.

RESULTS

Of 588 non-duplicated papers, data from 18 articles were included. Overall risk of bias was high risk in 8 studies, some concern in 9 studies and low risk in 1 study. Current evidence demonstrated that ADSCs transplantation could improve locomotion following SCI (standardized mean difference = 1.71; 95%CI 1.29-2.13; p < 0.0001). A considerable heterogeneity was observed between the studies (I² = 72.0%; p < 0.0001). Subgroup analysis and meta-regression revealed that most of the factors like injury model, the severity of SCI, treatment phase, injury location, and number of transplanted cells did not have a significant effect on the efficacy of ADSCs in improving locomotion following SCI (p_{for odds ratios} > 0.05).

CONCLUSION

We conclude that any number of ADSCs by any prescription routes can improve locomotion recovery in an SCI animal model, at any phase of SCI, with any severity. Given the remarkable bias about blinding, clinical translation of the present results is tough, because in addition to the complexity of the nervous system and the involvement of far more complex motor circuits in the human, blinding compliance and motor outcome assessment tests in animal studies and clinical trials are significantly different.

The rodent object-in-context task: A systematic review and meta-analysis of important variables

Environmental information plays an important role in remembering events. Information about stable aspects of the environment (here referred to as 'context') and the event are combined by the hippocampal system and stored as context-dependent memory. In rodents (such as rats and mice), context-dependent memory is often investigated with the object-in-context task. However, the implementation and interpretation of this task varies considerably across studies. This variation hampers the comparison between studies and-for those who design a new experiment or carry out pilot experiments-the estimation of whether observed behavior is within the expected range. Also, it is currently unclear which of the variables critically influence the outcome of the task. To address these issues, we carried out a preregistered systematic review (PROSPERO CRD42020191340) and provide an up-to-date overview of the animal-, task-, and protocol-related variations in the object-in-context task for rodents. Using a data-driven explorative meta-analysis we next identified critical factors influencing the outcome of this task, such as sex, testbox size and the delay between the learning trials. Based on these observations we provide recommendations on sex, strain, prior arousal, context (size, walls, shape, etc.) and timing (habituation, learning, and memory phase) to create more consensus in the set-up, procedure, and interpretation of the object-in-context task for rodents. This could contribute to a more robust and evidence-based design in future animal experiments.

Stem Cell-Based Therapy for Experimental Ischemic Stroke: A Preclinical Systematic Review

Stem cell transplantation offers promise in the treatment of ischemic stroke. Here we utilized systematic review, meta-analysis, and meta-regression to study the biological effect of stem cell treatments in animal models of ischemic stroke. A total of 98 eligible publications were included by searching PubMed, EMBASE, and Web of Science from inception to August 1, 2020. There are about 141 comparisons, involving 5,200 animals, that examined the effect of stem cell transplantation on neurological function and infarct volume as primary outcome measures in animal models for stroke. Stem cell-based therapy can improve both neurological function (effect size, −3.37; 95% confidence interval, −3.83 to −2.90) and infarct volume (effect size, −11.37; 95% confidence interval, −12.89 to −9.85) compared with controls. These results suggest that stem cell therapy could improve neurological function deficits and infarct volume, exerting potential neuroprotective effect for experimental ischemic stroke, but further clinical studies are still needed.

Delivery of chondroitinase by canine mucosal olfactory ensheathing cells alongside rehabilitation enhances recovery after spinal cord injury

Spinal cord injury (SCI) can cause chronic paralysis and incontinence and remains a major worldwide healthcare burden, with no regenerative treatment clinically available. Intraspinal transplantation of olfactory ensheathing cells (OECs) and injection of chondroitinase ABC (chABC) are both promising therapies but limited and unpredictable responses are seen, particularly in canine clinical trials. Sustained delivery of chABC presents a challenge due to its thermal instability; we hypothesised that transplantation of canine olfactory mucosal OECs genetically modified ex vivo by lentiviral transduction to express chABC (cOEC-chABC) would provide novel delivery of chABC and synergistic therapy. Rats were randomly divided into cOEC-chABC, cOEC, or vehicle transplanted groups and received transplant immediately after dorsal column crush corticospinal tract (CST) injury. Rehabilitation for forepaw reaching and blinded behavioural testing was conducted for 8 weeks. We show that cOEC-chABC transplanted animals recover greater forepaw reaching accuracy on Whishaw testing and more normal gait than cOEC transplanted or vehicle control rats. Increased CST axon sprouting cranial to the injury and serotonergic fibres caudal to the injury suggest a mechanism for recovery. We therefore demonstrate that cOECs can deliver sufficient chABC to drive modest functional improvement, and that this genetically engineered cellular and molecular approach is a feasible combination therapy for SCI.

The Protective Role of Immunomodulators on Tissue-Type Plasminogen Activator-Induced Hemorrhagic Transformation in Experimental Stroke: A Systematic Review and Meta-Analysis

Background: Recanalization with tissue plasminogen activator (tPA) is the only approved agent available for acute ischemic stroke. But delayed treatment of tPA may lead to lethal intracerebral hemorrhagic transformation (HT). Numerous studies have reported that immunomodulators have good efficacy on tPA-induced HT in ischemic stroke models. The benefits of immunomodulators on tPA-associated HT are not clearly defined. Here, we sought to conduct a systematic review and meta-analysis of preclinical studies to further evaluate the efficacy of immunomodulators.

Methods: The PubMed, Web of Science, and Scopus electronic databases were searched for studies. Studies that reported the efficacy of immunomodulators on tPA-induced HT in animal models of stroke were included. Animals were divided into two groups: immunomodulators plus tPA (intervention group) or tPA alone (control group). The primary outcome was intracerebral hemorrhage, and the secondary outcomes included infarct volume and neurobehavioral score. Study quality was assessed by the checklist of CAMARADES. We used standardized mean difference (SMD) to assess the impact of interventions. Regression analysis and subgroup analysis were performed to identify potential sources of heterogeneity and evaluate the impact of the study characteristics. The evidence of publication bias was evaluated using trim and fill method and Egger’s test.

Results: We identified 22 studies that met our inclusion criteria involving 516 animals and 42 different comparisons. The median quality checklist score was seven of a possible 10 (interquartile range, 6–8). Immunomodulators improved cerebral hemorrhage (1.31 SMD, 1.09–1.52); infarct volume (1.35 SMD, 0.95–1.76), and neurobehavioral outcome (0.9 SMD, 0.67–1.13) in experimental stroke. Regression analysis and subgroup analysis indicated that control of temperature and time of assessment were important factors that influencing the efficacy of immunomodulators.

Conclusion: Our findings suggested that immunomodulators had a favorable effect on tPA-associated intracerebral hemorrhage, cerebral infarction, and neurobehavioral impairments in animal models of ischemic stroke.

Antithrombotic Agents for tPA-Induced Cerebral Hemorrhage: A Systematic Review and Meta-Analysis of Preclinical Studies

Background

tPA (tissue‐type plasminogen activator) remains the only approved drug for acute ischemic stroke, with a potentially serious adverse effect: hemorrhagic transformation. The effects of antithrombotic agents on tPA‐induced hemorrhagic transformation after ischemic stroke are not clearly defined. We performed a systematic review and meta‐analysis in preclinical studies aiming to evaluate the efficacy of antithrombotic agents on tPA‐induced hemorrhagic transformation after ischemic stroke.

Methods and Results

We conducted a systematic review and meta‐analysis of studies testing antithrombotic agents in animal models of tPA‐induced hemorrhagic transformation. The pooled effects were calculated using random‐effects models, and heterogeneity was explored through meta‐regression and subgroup analyses. Publication bias was assessed using trim and fill method and the Egger test. The efficacy of 18 distinct interventions was described in 22 publications. The pooled data showed a significant improvement in cerebral hemorrhage, infarct size, and neurobehavioral outcome in treated compared with control animals (standardized mean difference, 0.45 [95% CI, 0.11–0.78]; standardized mean difference, 1.18 [95% CI, 0.73–1.64]; and standardized mean difference, 0.91 [95% CI, 0.49–1.32], respectively). Subgroup analysis indicated that quality score, random allocation, control of temperature, anesthetic used, stroke model used, route of drug delivery, time of drug administration, and time of assessment were significant factors that influenced the effects of interventions.

Conclusions

Administration with antiplatelet agents revealed statistically significant improvement in all the outcomes. Anticoagulant agents showed significant effects in infarct size and neurobehavioral score, but fibrinolytic agents did not show any significant improvement in all the outcomes. The conclusions should be interpreted cautiously given the heterogeneity and publication bias identified in this analysis.

Bilateral striatal transplantation of human olfactory stem cells ameliorates motor function, prevents necroptosis-induced cell death and improves striatal volume in the rat model of Huntington's disease

Cellular transplant therapy is one of the most common therapeutic strategies used to mitigate symptoms of neurodegenerative diseases such as Huntington's disease (HD). Briefly, the main goal of the present study was to investigate HD's motor deficits through the olfactory ecto-mesenchymals stem cells (OE-MSC) secretome. OE-MSCs were characterized immunophenotypically by the positive expression of CD73, CD90 and CD105. Also, three specific markers of OE-MSCs were obtained from the nasal cavity of human volunteers. The main features of OE-MSCs are their high proliferation, ease of harvesting and growth factor secretion. All animals were randomly assigned to three groups: control, 3-NP + vehicle treated and 3-NP + Cell groups. In both experimental groups, the subjects received intraperitoneal 3-NP (30 mg/kg) injections once a day for five consecutive days, followed by the bilateral intra-striatal implantation of OE-MSCs in the 3-NP + Cell group. Muscular function was assessed by electromyography and rotarod test, and the locomotor function was evaluated using the open field test. According to our findings, striatal transplants of OE-MSCs reduced microglial inflammatory factor, the tumor necrosis factor (TNFα) in the 3-NP + Cell group, with a significant reduction in RIP3, the markers of necroptosis in striatum. In addition to the remarkable recovery of the striatal volume after engraftment, the motor activities were enhanced in the 3-NP + cell group compared to the 3-NP + vehicle group. Taken together, our results demonstrated the in vivo advantages of OE-MSCs treatment in an HD rat model with numerous positive paracrine effects including behavioral and anatomical recovery.

Progress in Stem Cell Therapy for Spinal Cord Injury

Background

Spinal cord injury (SCI) is one of the serious neurological diseases that occur in young people with high morbidity and disability. However, there is still a lack of effective treatments for it. Stem cell (SC) treatment of SCI has gradually become a new research hotspot over the past decades. This article is aimed at reviewing the research progress of SC therapy for SCI.

Methods

Review the literature and summarize the effects, strategies, related mechanisms, safety, and clinical application of different SC types and new approaches in combination with SC in SCI treatment.

Results

A large number of studies have focused on SC therapy for SCI, most of which showed good effects. The common SC types for SCI treatment include mesenchymal stem cells (MSCs), hematopoietic stem cells (HSCs), neural stem cells (NSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The modes of treatment include in vivo and in vitro induction. The pathways of transplantation consist of intravenous, transarterial, nasal, intraperitoneal, intrathecal, and intramedullary injections. Most of the SC treatments for SCI use a number of cells ranging from tens of thousands to millions. Early or late SC administration, application of immunosuppressant or not are still controversies. Potential mechanisms of SC therapy include tissue repair and replacement, neurotrophy, and regeneration and promotion of angiogenesis, antiapoptosis, and anti-inflammatory. Common safety issues include thrombosis and embolism, tumorigenicity and instability, infection, high fever, and even death. Recently, some new approaches, such as the pharmacological activation of endogenous SCs, biomaterials, 3D print, and optogenetics, have been also developed, which greatly improved the application of SC therapy for SCI.

Conclusion

Most studies support the effects of SC therapy on SCI, while a few studies do not. The cell types, mechanisms, and strategies of SC therapy for SCI are very different among studies. In addition, the safety cannot be ignored, and more clinical trials are required. The application of new technology will promote SC therapy of SCI.

Transplanting neural progenitor cells to restore connectivity after spinal cord injury

Spinal cord injury remains a scientific and therapeutic challenge with great cost to individuals and society. The goal of research in this field is to find a means of restoring lost function. Recently we have seen considerable progress in understanding the injury process and the capacity of CNS neurons to regenerate, as well as innovations in stem cell biology. This presents an opportunity to develop effective transplantation strategies to provide new neural cells to promote the formation of new neuronal networks and functional connectivity. Past and ongoing clinical studies have demonstrated the safety of cell therapy, and preclinical research has used models of spinal cord injury to better elucidate the underlying mechanisms through which donor cells interact with the host and thus increase long-term efficacy. While a variety of cell therapies have been explored, we focus here on the use of neural progenitor cells obtained or derived from different sources to promote connectivity in sensory, motor and autonomic systems.

Tubular scaffold with microchannels and an H-shaped lumen loaded with bone marrow stromal cells promotes neuroregeneration and inhibits apoptosis after spinal cord injury

As a result of its complex histological structure, regeneration patterns of grey and white matter are quite different in the spinal cord. Therefore, tissue engineering scaffolds for repairing spinal cord injury must be able to adapt to varying neural regeneration patterns. The aim of the present study was to improve a previously reported spinal cord‐mimicking partition‐type scaffold by adding microchannels on a single tubular wall along its longitudinal axis, thus integrating the two architectures of a single H‐shaped central tube and many microchannels. Next, the integrated scaffold was loaded with bone marrow stromal cells (BMSCs) and transplanted to bridge the 5‐mm defect of a complete transverse lesion in the thoracic spinal cord of rats. Subsequently, effects on nerve regeneration, locomotion function recovery, and early neuroprotection were observed. After 1 year of repair, the integrated scaffold could guide the regeneration of axons appearing in the debris of degraded microchannels, especially serotonin receptor 1A receptor‐positive axonal tracts, which were relatively orderly arranged. Moreover, a network of nerve fibres was present, and a few BMSCs expressed neuronal markers in tubular lumens. Functionally, electrophysiological and locomotor functions of rats were partially recovered. In addition, we found that BMSCs could protect neurons and oligodendrocytes from apoptosis during the early stage of implantation. Taken together, our results demonstrate the potential of this novel integrated scaffold loaded with BMSCs to promote spinal cord regeneration through mechanical guidance and neuroprotective mechanisms.

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.

The effects of cell therapy on seizures in animal models of epilepsy: protocol for systematic review and meta-analysis of preclinical studies

BACKGROUND

Epilepsy is one of the most common and serious brain conditions, characterised by recurrent unprovoked seizures. It affects about 1% of the population worldwide. Despite a range of antiepileptic drugs being available, one third of the patients do not achieve adequate seizure control. Only a minority of these patients may be suitable to undergo surgical resection of the seizure focus, but this is an invasive and not always successful procedure. There is an urgent need to develop more effective treatment options for uncontrolled seizures. With the recent advances in regenerative and translational medicine, cell therapies could prove to be beneficial. Here we describe the protocol for a proposed systematic review and meta-analysis to assess the effects for cell transplantation in animal models of epilepsy.

METHODS

We will include all preclinical animal models of epilepsy that evaluate the effects of cell transplantation compared to the untreated control. The primary outcome will be the change in frequency and duration of seizures from baseline measured by video electroencephalography (EEG). The secondary outcomes will include histological and neurobehavioural assessments. We will perform an electronic search of MEDLINE via PubMed, Web of Science, and EMBASE. Search results will be screened independently by two reviewers and confirmed by a third reviewer. Data from eligible studies will be extracted and pooled, and the summary estimate of effect size will be calculated using DerSimonian and Laird random effects meta-analysis. Heterogeneity will be explored using sub-group meta-analysis, and meta-regression risk of bias will be assessed by using the CAMARADES checklist for study quality tool.

DISCUSSION

The purpose of this systematic review is to assess and summarise the existing literature in the field of cell transplantation as a treatment for epilepsy in animal models. Efficacy will be measured by evaluating the reduction in seizure intervals, number, and duration, within animal models of epilepsy. Analysis of the existing literature will mark the achievement made in the field and locate the existing gaps, a process that will aid in the search for the next needed step.

SYSTEMATIC REVIEW REGISTRATION

CRD42018103628.

Use of adult mesenchymal stromal cells in tissue repair: impact of physical exercise

Physical exercise (PE) has unquestionable beneficial effects on health, which likely extend into several organ-to-cell physiological processes. At the cell scale, endogenous mesenchymal stromal cells (MSCs) contribute to tissue repair, although their repair capacities may be insufficient in paucicellular or severely damaged tissues. For this reason, MSC transplantation holds great promise for tissue repair. With the goals of understanding if PE has beneficial effects on MSC biology and if PE potentiates their role in tissue repair, we reviewed literature reports regarding the effects of PE on MSC properties (specifically, proliferation, differentiation, and homing) and of a combination of PE and MSC transplantation on tissue repair (specifically neural, cartilage, and muscular tissues). Contradictory results have been reported; interpretation is complicated because various and different species, cell sources, and experimental protocols, specifically exercise programs, have been used. On the basis of these data, the effects of exercise on MSC proliferation and differentiation depend on exercise characteristics (type, intensity, duration, etc.) and on the characteristics of the tissue from which the MSCs were collected. For the in vitro studies, the level of strain (and other details of the mechanical stimulus), the time elapsed between the end of exposure to strain and MSC collection, the age of the donors, as well as the passage number at which the MSCs are evaluated also play a role. The combination of PE and MSC engraftment improves neural, cartilage, and muscular tissue recovery, but it is not clear whether the effects of MSCs and exercise are additive or synergistic.

Outcome heterogeneity and bias in acute experimental spinal cord injury: A meta-analysis

OBJECTIVE

To determine whether and to what degree bias and underestimated variability undermine the predictive value of preclinical research for clinical translation.

METHODS

We investigated experimental spinal cord injury (SCI) studies for outcome heterogeneity and the impact of bias. Data from 549 preclinical SCI studies including 9,535 animals were analyzed with meta-regression to assess the effect of various study characteristics and the quality of neurologic recovery.

RESULTS

Overall, the included interventions reported a neurobehavioral outcome improvement of 26.3% (95% confidence interval 24.3-28.4). Response to treatment was dependent on experimental modeling paradigms (neurobehavioral score, site of injury, and animal species). Applying multiple outcome measures was consistently associated with smaller effect sizes compared with studies applying only 1 outcome measure. More than half of the studies (51.2%) did not report blinded assessment, constituting a likely source of evaluation bias, with an overstated effect size of 7.2%. Assessment of publication bias, which extrapolates to identify likely missing data, suggested that between 2% and 41% of experiments remain unpublished. Inclusion of these theoretical missing studies suggested an overestimation of efficacy, reducing the effect sizes by between 0.9% and 14.3%.

CONCLUSIONS

We provide empirical evidence of prevalent bias in the design and reporting of experimental SCI studies, resulting in overestimation of the effectiveness. Bias compromises the internal validity and jeopardizes the successful translation of SCI therapies from the bench to bedside.

Combination of stem cells from deciduous teeth and electroacupuncture for therapy in dogs with chronic spinal cord injury: A pilot study

Spinal cord injury (SCI) is a serious condition that causes profound economic and emotional impact in human patients and companion animal owners. It has been shown that the neurogenic effects of the stem cells are enhanced when combined with electroacupuncture (EA) in rodent models of SCI. To determine the safety and feasibility of combining transplantation of allogenic stem cells derived from canine exfoliated deciduous teeth (SCED) and EA in dogs with chronic spinal cord injury a canine pilot clinical study was conducted. A total of 16 individuals ranging from 5 to 11 years at 3 to 18 months of injury were investigated and randomly assigned to 4 experimental groups (SCED, EA, SCED + EA, control). Mild neurological and functional improvements were seen in all 4 groups. There was no clinical progression or mortality of the cases occurred in a follow up of 7 months after procedure. The study shows that SCED transplantation and electroacupuncture were feasible, safe and potentially beneficial. However Long-term patient monitoring is necessary to rule out any delayed side effects and assess any further improvements.

Human Ischaemic Cascade Studies Using SH-SY5Y Cells: a Systematic Review and Meta-Analysis

Low translational yield for stroke may reflect the focus of discovery science on rodents rather than humans. Just how little is known about human neuronal ischaemic responses is confirmed by systematic review and meta-analysis revealing that data for the most commonly used SH-SY5Y human cells comprises only 84 papers. Oxygen-glucose deprivation, H2O2, hypoxia, glucose-deprivation and glutamate excitotoxicity yielded - 58, - 61, - 29, - 45 and - 49% injury, respectively, with a dose-response relationship found only for H2O2 injury (R2 = 29.29%, p < 0.002). Heterogeneity (I2 = 99.36%, df = 132, p < 0.0001) was largely attributable to the methods used to detect injury (R2 = 44.77%, p < 0.000) with cell death assays detecting greater injury than survival assays (- 71 vs - 47%, R2 = 28.64%, p < 0.000). Seventy-four percent of publications provided no description of differentiation status, but in the 26% that did, undifferentiated cells were susceptible to greater injury (R2 = 4.13%, p < 0.047). One hundred and sixty-nine interventions improved average survival by 34.67% (p < 0.0001). Eighty-eight comparisons using oxygen-glucose deprivation found both benefit and harm, but studies using glutamate and H2O2 injury reported only improvement. In studies using glucose deprivation, intervention generally worsened outcome. There was insufficient data to rank individual interventions, but of the studies reporting greatest improvement (> 90% effect size), 7/13 were of herbal medicine constituents (24.85% of the intervention dataset). We conclude that surprisingly little is known of the human neuronal response to ischaemic injury, and that the large impact of methodology on outcome indicates that further model validation is required. Lack of evidence for randomisation, blinding or power analysis suggests that the intervention data is at substantial risk of bias.

The Effect of Human Mesenchymal Stem Cells Derived from Wharton's Jelly in Spinal Cord Injury Treatment Is Dose-Dependent and Can Be Facilitated by Repeated Application

Human mesenchymal stem cells derived from Wharton’s jelly (WJ-MSCs) were used for the treatment of the ischemic-compression model of spinal cord injury in rats. To assess the effectivity of the treatment, different dosages (0.5 or 1.5 million cells) and repeated applications were compared. Cells or saline were applied intrathecally by lumbar puncture for one week only, or in three consecutive weeks after injury. Rats were assessed for locomotor skills (BBB, rotarod, flat beam) for 9 weeks. Spinal cord tissue was morphometrically analyzed for axonal sprouting, sparing of gray and white matter and astrogliosis. Endogenous gene expression (Gfap, Casp3, Irf5, Cd86, Mrc1, Cd163) was studied with quantitative Real-time polymerase chain reaction (qRT PCR). Significant recovery of functional outcome was observed in all of the treated groups except for the single application of the lowest number of cells. Histochemical analyses revealed a gradually increasing effect of grafted cells, resulting in a significant increase in the number of GAP43+ fibers, a higher amount of spared gray matter and reduced astrogliosis. mRNA expression of macrophage markers and apoptosis was downregulated after the repeated application of 1.5 million cells. We conclude that the effect of hWJ-MSCs on spinal cord regeneration is dose-dependent and potentiated by repeated application.

Current Perspectives regarding Stem Cell-Based Therapy for Alzheimer's Disease

Alzheimer's disease (AD), a progressive neurodegenerative disorder featuring memory loss and cognitive impairment, is caused by synaptic failure and the excessive accumulation of misfolded proteins. Many unsuccessful attempts have been made to develop new small molecules or antibodies to intervene in the disease's pathogenesis. Stem cell-based therapies cast a new hope for AD treatment as a replacement or regeneration strategy. The results from recent preclinical studies regarding stem cell-based therapies are promising. Human clinical trials are now underway. However, a number of questions remain to be answered prior to safe and effective clinical translation. This review explores the pathophysiology of AD and summarizes the relevant stem cell research according to cell type. We also briefly summarize related clinical trials. Finally, future perspectives are discussed with regard to their clinical applications.

Isolation and characterization of olfactory ecto-mesenchymal stem cells from eight mammalian genera

BACKGROUND

Stem cell-based therapies are an attractive option to promote regeneration and repair defective tissues and organs. Thanks to their multipotency, high proliferation rate and the lack of major ethical limitations, "olfactory ecto-mesenchymal stem cells" (OE-MSCs) have been described as a promising candidate to treat a variety of damaged tissues. Easily accessible in the nasal cavity of most mammals, these cells are highly suitable for autologous cell-based therapies and do not face issues associated with other stem cells. However, their clinical use in humans and animals is limited due to a lack of preclinical studies on autologous transplantation and because no well-established methods currently exist to cultivate these cells. Here we evaluated the feasibility of collecting, purifying and amplifying OE-MSCs from different mammalian genera with the goal of promoting their interest in veterinary regenerative medicine. Biopsies of olfactory mucosa from eight mammalian genera (mouse, rat, rabbit, sheep, dog, horse, gray mouse lemur and macaque) were collected, using techniques derived from those previously used in humans and rats. The possibility of amplifying these cells and their stemness features and differentiation capability were then evaluated.

RESULTS

Biopsies were successfully performed on olfactory mucosa without requiring the sacrifice of the donor animal, except mice. Cell populations were rapidly generated from olfactory mucosa explants. These cells displayed similar key features of their human counterparts: a fibroblastic morphology, a robust expression of nestin, an ability to form spheres and similar expression of surface markers (CD44, CD73). Moreover, most of them also exhibited high proliferation rates and clonogenicity with genus-specific properties. Finally, OE-MSCs also showed the ability to differentiate into mesodermal lineages.

CONCLUSIONS

This article describes for the first time how millions of OE-MSCs can be quickly and easily obtained from different mammalian genera through protocols that are well-suited for autologous transplantations. Moreover, their multipotency makes them relevant to evaluate therapeutic application in a wide variety of tissue injury models. This study paves the way for the development of new fundamental and clinical studies based on OE-MSCs transplantation and suggests their interest in veterinary medicine.

Biomaterial-Supported Cell Transplantation Treatments for Spinal Cord Injury: Challenges and Perspectives

Spinal cord injury (SCI), resulting in para- and tetraplegia caused by the partial or complete disruption of descending motor and ascending sensory neurons, represents a complex neurological condition that remains incurable. Following SCI, numerous obstacles comprising of the loss of neural tissue (neurons, astrocytes, and oligodendrocytes), formation of a cavity, inflammation, loss of neuronal circuitry and function must be overcome. Given the multifaceted primary and secondary injury events that occur with SCI treatment options are likely to require combinatorial therapies. While several methods have been explored, only the intersection of two, cell transplantation and biomaterial implantation, will be addressed in detail here. Owing to the constant advance of cell culture technologies, cell-based transplantation has come to the forefront of SCI treatment in order to replace/protect damaged tissue and provide physical as well as trophic support for axonal regrowth. Biomaterial scaffolds provide cells with a protected environment from the surrounding lesion, in addition to bridging extensive damage and providing physical and directional support for axonal regrowth. Moreover, in this combinatorial approach cell transplantation improves scaffold integration and therefore regenerative growth potential. Here, we review the advances in combinatorial therapies of Schwann cells (SCs), astrocytes, olfactory ensheathing cells (OECs), mesenchymal stem cells, as well as neural stem and progenitor cells (NSPCs) with various biomaterial scaffolds.

Identification and characterization of outcome measures reported in animal models of epilepsy: Protocol for a systematic review of the literature-A TASK2 report of the AES/ILAE Translational Task Force of the ILAE

Current antiseizure therapy is ineffective in approximately one third of people with epilepsy and is often associated with substantial side effects. In addition, most current therapeutic paradigms offer treatment, but not cure, and no therapies are able to modify the underlying disease, that is, can prevent or halt the process of epileptogenesis or alleviate the cognitive and psychiatric comorbidities. Preclinical research in the field of epilepsy has been extensive, but unfortunately, not all the animal models being used have been validated for their predictive value. The overall goal of TASK2 of the AES/ILAE Translational Task Force is to organize and coordinate systematic reviews on selected topics regarding animal research in epilepsy. Herein we describe our strategy. In the first part of the paper we provide an overview of the usefulness of systematic reviews and meta-analysis for preclinical research and explain the essentials for their conduct. Then we describe in detail the protocol for a first systematic review, which will focus on the identification and characterization of outcome measures reported in animal models of epilepsy. The specific goals of this study are to define systematically the phenotypic characteristics of the most commonly used animal models, and to effectively compare these with the manifestations of human epilepsy. This will provide epilepsy researchers with detailed information on the strengths and weaknesses of epilepsy models, facilitating their refinement and future research. Ultimately, this could lead to a refined use of relevant models for understanding the mechanism(s) of the epilepsies and developing novel therapies.

Current Nucleic Acid Extraction Methods and Their Implications to Point-of-Care Diagnostics

Nucleic acid extraction (NAE) plays a vital role in molecular biology as the primary step for many downstream applications. Many modifications have been introduced to the original 1869 method. Modern processes are categorized into chemical or mechanical, each with peculiarities that influence their use, especially in point-of-care diagnostics (POC-Dx). POC-Dx is a new approach aiming to replace sophisticated analytical machinery with microanalytical systems, able to be used near the patient, at the point of care or point of need. Although notable efforts have been made, a simple and effective extraction method is still a major challenge for widespread use of POC-Dx. In this review, we dissected the working principle of each of the most common NAE methods, overviewing their advantages and disadvantages, as well their potential for integration in POC-Dx systems. At present, it seems difficult, if not impossible, to establish a procedure which can be universally applied to POC-Dx. We also discuss the effects of the NAE chemicals upon the main plastic polymers used to mass produce POC-Dx systems. We end our review discussing the limitations and challenges that should guide the quest for an efficient extraction method that can be integrated in a POC-Dx system.

Publication bias in animal research presented at the 2008 Society of Critical Care Medicine Conference

Background

To determine a direct measure of publication bias by determining subsequent full-paper publication (P) of studies reported in animal research abstracts presented at an international conference (A).

Methods

We selected 100 random (using a random-number generator) A from the 2008 Society of Critical Care Medicine Conference. Using a data collection form and study manual, we recorded methodology and result variables from A. We searched PubMed and EMBASE to June 2015, and DOAJ and Google Scholar to May 2017 to screen for subsequent P. Methodology and result variables were recorded from P to determine changes in reporting from A. Predictors of P were examined using Fisher’s Exact Test.

Results

62% (95% CI 52–71%) of studies described in A were subsequently P after a median 19 [IQR 9–33.3] months from conference presentation. Reporting of studies in A was of low quality: randomized 27% (the method of randomization and allocation concealment not described), blinded 0%, sample-size calculation stated 0%, specifying the primary outcome 26%, numbers given with denominators 6%, and stating number of animals used 47%. Only being an orally presented (vs. poster presented) A (14/16 vs. 48/84, p = 0.025) predicted P. Reporting of studies in P was of poor quality: randomized 39% (the method of randomization and allocation concealment not described), likely blinded 6%, primary outcome specified 5%, sample size calculation stated 0%, numbers given with denominators 34%, and number of animals used stated 56%. Changes in reporting from A to P occurred: from non-randomized to randomized 19%, from non-blinded to blinded 6%, from negative to positive outcomes 8%, from having to not having a stated primary outcome 16%, and from non-statistically to statistically significant findings 37%. Post-hoc, using publication data, P was predicted by having positive outcomes (published 62/62, unpublished 33/38; p = 0.003), or statistically significant results (published 58/62, unpublished 20/38; p < 0.001).

Conclusions

Only 62% (95% CI 52–71%) of animal research A are subsequently P; this was predicted by oral presentation of the A, finally having positive outcomes, and finally having statistically significant results. Publication bias is prevalent in critical care animal research.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-017-2574-0) contains supplementary material, which is available to authorized users.

Generating level-dependent models of cervical and thoracic spinal cord injury: Exploring the interplay of neuroanatomy, physiology, and function

The majority of spinal cord injuries (SCI) occur at the cervical level, which results in significant impairment. Neurologic level and severity of injury are primary endpoints in clinical trials; however, how level-specific damages relate to behavioural performance in cervical injury is incompletely understood. We hypothesized that ascending level of injury leads to worsening forelimb performance, and correlates with loss of neural tissue and muscle-specific neuron pools. A direct comparison of multiple models was made with injury realized at the C5, C6, C7 and T7 vertebral levels using clip compression with sham-operated controls. Animals were assessed for 10weeks post-injury with numerous (40) outcome measures, including: classic behavioural tests, CatWalk, non-invasive MRI, electrophysiology, histologic lesion morphometry, neuron counts, and motor compartment quantification, and multivariate statistics on the total dataset. Histologic staining and T1-weighted MR imaging revealed similar structural changes and distinct tissue loss with cystic cavitation across all injuries. Forelimb tests, including grip strength, F-WARP motor scale, Inclined Plane, and forelimb ladder walk, exhibited stratification between all groups and marked impairment with C5 and C6 injuries. Classic hindlimb tests including BBB, hindlimb ladder walk, bladder recovery, and mortality were not different between cervical and thoracic injuries. CatWalk multivariate gait analysis showed reciprocal and progressive changes forelimb and hindlimb function with ascending level of injury. Electrophysiology revealed poor forelimb axonal conduction in cervical C5 and C6 groups alone. The cervical enlargement (C5-T2) showed progressive ventral horn atrophy and loss of specific motor neuron populations with ascending injury. Multivariate statistics revealed a robust dataset, rank-order contribution of outcomes, and allowed prediction of injury level with single-level discrimination using forelimb performance and neuron counts. Level-dependent models were generated using clip-compression SCI, with marked and reliable differences in forelimb performance and specific neuron pool loss.

The efficacy of probiotics as pharmacological treatment of cutaneous wounds: Meta-analysis of animal studies

The aim of the current meta-analysis of animal studies was to evaluate the efficacy of probiotics as pharmacological treatment of cutaneous wounds. A systematic electronic literature search was conducted and in total six animal studies which undertake twelve experiments met our inclusion criteria. We used the percentage (%) of wound area at the end of the first week after initial wounding to evaluate the efficacy of the probiotic treatment. The heterogeneity was estimated as statistically significant (p<0.0001) and therefore the meta-analysis was performed with the random-effect model. Based on the estimated Hedges' g (Hedges, 1982), the administration of probiotics was associated with acceleration of the wound contraction (g=-2.55; 95%CI=-3.59, -1.50; p<0.0001). The meta-regression analysis showed that the moderator sterile kefir extract has the greater effect on the overall estimated efficacy of probiotic treatment (g=-5.6983; p=0.0442) with bacteria probiotic therapies (70% kefir gel, L. brevis, L. fermentum, L. plantarum, L. reuteri) following (g=-2.3814; p=0.0003). For bacteria dose moderator, the results showed that increase in bacterial dose corresponds to increase of the estimated overall effect size (g=-10.2056; p=0.0053). The linear regression test of funnel plot asymmetry showed absence of publication bias. In conclusion, the results indicate that probiotics administration is an effective pharmacological treatment of cutaneous wounds. However, due to the heterogeneity among studies, further research is required.

ADSC-sheet Transplantation to Prevent Stricture after Extended Esophageal Endoscopic Submucosal Dissection

In past years, the cell-sheet construct has spurred wide interest in regenerative medicine, especially for reconstructive surgery procedures. The development of diversified technologies combining adipose tissue-derived stromal cells (ADSCs) with various biomaterials has led to the construction of numerous types of tissue-engineered substitutes, such as bone, cartilage, and adipose tissues from rodent, porcine, or human ADSCs. Extended esophageal endoscopic submucosal dissection (ESD) is responsible for esophageal stricture formation. Stricture prevention remains challenging, with no efficient treatments available. Previous studies reported the effectiveness of mucosal cell-sheet transplantation in a canine model and in humans. ADSCs are attributed anti-inflammatory properties, local immune modulating effects, neovascularization induction, and differentiation abilities into mesenchymal and non-mesenchymal lineages. This original study describes the endoscopic transplantation of an ADSC tissue-engineered construct to prevent esophageal stricture in a swine model. The ADSC construct was composed of two allogenic ADSC sheets layered upon each other on a paper support membrane. The ADSCs were labeled with the PKH67 fluorophore to allow probe-based confocal laser endomicroscopy (pCLE) monitoring. On the day of transplantation, a 5-cm and hemi-circumferential ESD known to induce esophageal stricture was performed. Animals were immediately endoscopically transplanted with 4 ADSC constructs. The complete adhesion of the ADSC constructs was obtained after 10 min of gentle application. Animals were sacrificed on day 28. All animals were successfully transplanted. Transplantation was confirmed on day 3 with a positive pCLE evaluation. Compared to transplanted animals, control animals developed severe strictures, with major fibrotic tissue development, more frequent alimentary trouble, and reduced weight gain. In our model, the transplantation of allogenic ADSCs, organized in double cell sheets, after extended ESD was successful and strongly associated with a lower esophageal stricture rate.

Clinical Study of NeuroRegen Scaffold Combined With Human Mesenchymal Stem Cells for the Repair of Chronic Complete Spinal Cord Injury

Regeneration of damaged neurons and recovery of sensation and motor function after complete spinal cord injury (SCI) are challenging. We previously developed a collagen scaffold, NeuroRegen, to promote axonal growth along collagen fibers and inhibit glial scar formation after SCI. When functionalized with multiple biomolecules, this scaffold promoted neurological regeneration and functional recovery in animals with SCI. In this study, eight patients with chronic complete SCI were enrolled to examine the safety and efficacy of implanting NeuroRegen scaffold with human umbilical cord mesenchymal stem cells (hUCB-MSCs). Using intraoperative neurophysiological monitoring, we identified and surgically resected scar tissues to eliminate the inhibitory effect of glial scarring on nerve regeneration. We then implanted NeuroRegen scaffold loaded with hUCB-MSCs into the resection sites. No adverse events (infection, fever, headache, allergic reaction, shock, perioperative complications, aggravation of neurological status, or cancer) were observed during 1 year of follow-up. Primary efficacy outcomes, including expansion of sensation level and motor-evoked potential (MEP)-responsive area, increased finger activity, enhanced trunk stability, defecation sensation, and autonomic neural function recovery, were observed in some patients. Our findings suggest that combined application of NeuroRegen scaffold and hUCB-MSCs is safe and feasible for clinical therapy in patients with chronic SCI. Our study suggests that construction of a regenerative microenvironment using a scaffold-based strategy may be a possible future approach to SCI repair.