Stem Cell Derived Extracellular Vesicle Therapy for Multiple Sclerosis, A Systematic Review and Meta-Analysis of Preclinical Studies

Stem cell therapy holds promise for multiple sclerosis (MS), with efficacy of different stem cell types reported across a range of preclinical MS animal models. While stem cell therapy has been approved for a small number of diseases in humans, extracellular vesicles (EVs) may provide an efficacious, cost-effective, and safer alternative to stem cell therapy. To this end, we conducted a systematic review with meta-analysis to assess the effectiveness of stem cell-derived secretome (EV and conditioned media (CM)) in animal models of MS. The data were extracted to calculate standardized mean differences for primary outcome measure of disease severity, using a random effect model. Additionally, several subgroup analyses were conducted to assess the impact of various study variables such as stem cell type and source, stem cell modification, route and time of administration, number of animals and animal's age, and EV isolation methods on secondary outcome. Publication quality and risk of bias were assessed. Overall, 19 preclinical studies were included in the meta-analysis where stem cell EV/CM was found to significantly reduce disease severity in EV-treated (SMD = 2, 95% CI: 1.18-2.83, P < .00001) and CM-treated animals (SMD = 2.58, 95% CI: 1.34-3.83, P < .00001) compared with controls. Our analysis indicated that stem cell secretome has a positive effect on reducing demyelination, systemic neuroinflammation, and disease severity in preclinical models of MS. These findings indicate a potential therapeutic effect that merits investigation and validation in clinical settings.

Neuroprotective Action of Tacrolimus before and after Onset of Neonatal Hypoxic-Ischaemic Brain Injury in Rats

(1) Background: Neonatal brain injury can lead to permanent neurodevelopmental impairments. Notably, suppressing inflammatory pathways may reduce damage. To determine the role of neuroinflammation in the progression of neonatal brain injury, we investigated the effect of treating neonatal rat pups with the immunosuppressant tacrolimus at two time points: before and after hypoxic-ischaemic (HI)-induced injury. (2) Methods: To induce HI injury, postnatal day (PND) 10 rat pups underwent single carotid artery ligation followed by hypoxia (8% oxygen, 90 min). Pups received daily tacrolimus (or a vehicle) starting either 3 days before HI on PND 7 (pre-HI), or 12 h after HI (post-HI). Four doses were tested: 0.025, 0.05, 0.1 or 0.25 mg/kg/day. Pups were euthanised at PND 17 or PND 50. (3) Results: All tacrolimus doses administered pre-HI significantly reduced brain infarct size and neuronal loss, increased the number of resting microglia and reduced cellular apoptosis (p < 0.05 compared to control). In contrast, only the highest dose of tacrolimus administered post-HI (0.25 mg/kg/day) reduced brain infarct size (p < 0.05). All doses of tacrolimus reduced pup weight compared to the controls. (4) Conclusions: Tacrolimus administration 3 days pre-HI was neuroprotective, likely mediated through neuroinflammatory and cell death pathways. Tacrolimus post-HI may have limited capacity to reduce brain injury, with higher doses increasing rat pup mortality. This work highlights the benefits of targeting neuroinflammation during the acute injurious period. More specific targeting of neuroinflammation, e.g., via T-cells, warrants further investigation.

Advances in neonatal cell therapies: Proceedings of the First Neonatal Cell Therapies Symposium (2022)

Despite considerable advances, there is a need to improve the outcomes of newborn infants, especially related to prematurity, encephalopathy and other conditions. In principle, cell therapies have the potential to protect, repair, or sometimes regenerate vital tissues; and improve or sustain organ function. In this review, we present highlights from the First Neonatal Cell Therapies Symposium (2022). Cells tested in preclinical and clinical studies include mesenchymal stromal cells from various sources, umbilical cord blood and cord tissue derived cells, and placental tissue and membrane derived cells. Overall, most preclinical studies suggest potential for benefit, but many of the cells tested were not adequately defined, and the optimal cell type, timing, frequency, cell dose or the most effective protocols for the targeted conditions is not known. There is as yet no clinical evidence for benefit, but several early phase clinical trials are now assessing safety in newborn babies. We discuss parental perspectives on their involvement in these trials, and lessons learnt from previous translational work of promising neonatal therapies. Finally, we make a call to the many research groups around the world working in this exciting yet complex field, to work together to make substantial and timely progress to address the knowledge gaps and move the field forward. IMPACT: Survival of preterm and sick newborn infants is improving, but they continue to be at high risk of many systemic and organ-specific complications. Cell therapies show promising results in preclinical models of various neonatal conditions and early phase clinical trials have been completed or underway. Progress on the potential utility of cell therapies for neonatal conditions, parental perspectives and translational aspects are discussed in this paper.

Factors Influencing the Efficacy of Umbilical Cord Blood-Derived Cell Therapy for Perinatal Brain Injury

INTRODUCTION

We have previously described preclinical literature which supports umbilical cord blood-derived cell (UCBC) therapy as an efficacious treatment for perinatal brain injury. However, efficacy of UCBCs may be influenced by different patient population and intervention characteristics.

OBJECTIVES

To systematically review the effects of UCBCs on brain outcomes in animal models of perinatal brain injury across subgroups to better understand the contribution of model type (preterm versus term), brain injury type, UCB cell type, route of administration, timing of intervention, cell dosage, and number of doses.

METHODS

A systematic search of MEDLINE and Embase databases was performed to identify studies using UCBC therapy in animal models of perinatal brain injury. Subgroup differences were measured by chi2 test where possible.

RESULTS

Differential benefits of UCBCs were seen across a number of subgroup analyses including intraventricular hemorrhage (IVH) vs. hypoxia ischemia (HI) model (apoptosis white matter (WM): chi2 = 4.07; P = .04, neuroinflammation-TNF-α: chi2 = 5.99; P = .01), UCB-derived mesenchymal stromal cells (MSCs) vs. UCB-derived mononuclear cells (MNCs) (oligodendrocyte WM: chi2 = 5.01; P = .03, neuroinflammation-TNF-α: chi2 = 3.93; P = .05, apoptosis grey matter (GM), astrogliosis WM), and intraventricular/intrathecal vs. systemic routes of administration (microglial activation GM: chi2 = 7.51; P = .02, astrogliosis WM: chi2 = 12.44; P = .002). We identified a serious risk of bias and overall low certainty of evidence.

CONCLUSIONS

Preclinical evidence suggests UCBCs to show greater efficacy in the injury model of IVH compared to HI, the use of UCB-MSCs compared to UCB-MNCs and the use of local administrative routes compared to systemic routes in animal models of perinatal brain injury. Further research is needed to improve certainty of evidence and address knowledge gaps.

Umbilical Cord Blood-Derived Cell Therapy for Perinatal Brain Injury: A Systematic Review & Meta-Analysis of Preclinical Studies

Perinatal brain injury is a major contributor to long-term adverse neurodevelopment. There is mounting preclinical evidence for use of umbilical cord blood (UCB)-derived cell therapy as potential treatment. To systematically review and analyse effects of UCB-derived cell therapy on brain outcomes in preclinical models of perinatal brain injury. MEDLINE and Embase databases were searched for relevant studies. Brain injury outcomes were extracted for meta-analysis to calculate standard mean difference (SMD) with 95% confidence interval (CI), using an inverse variance, random effects model. Outcomes were separated based on grey matter (GM) and white matter (WM) regions where applicable. Risk of bias was assessed using SYRCLE, and GRADE was used to summarise certainty of evidence. Fifty-five eligible studies were included (7 large, 48 small animal models). UCB-derived cell therapy significantly improved outcomes across multiple domains, including decreased infarct size (SMD 0.53; 95% CI (0.32, 0.74), p < 0.00001), apoptosis (WM, SMD 1.59; 95%CI (0.86, 2.32), p < 0.0001), astrogliosis (GM, SMD 0.56; 95% CI (0.12, 1.01), p = 0.01), microglial activation (WM, SMD 1.03; 95% CI (0.40, 1.66), p = 0.001), neuroinflammation (TNF-α, SMD 0.84; 95%CI (0.44, 1.25), p < 0.0001); as well as improved neuron number (SMD 0.86; 95% CI (0.39, 1.33), p = 0.0003), oligodendrocyte number (GM, SMD 3.35; 95 %CI (1.00, 5.69), p = 0.005) and motor function (cylinder test, SMD 0.49; 95 %CI (0.23, 0.76), p = 0.0003). Risk of bias was determined as serious, and overall certainty of evidence was low. UCB-derived cell therapy is an efficacious treatment in pre-clinical models of perinatal brain injury, however findings are limited by low certainty of evidence.

Proportion of Infant Neurodevelopment Trials Reporting a Null Finding: A Systematic Review

CONTEXT

Discovering new interventions to improve neurodevelopmental outcomes is a priority; however, clinical trials are challenging and methodological issues may impact the interpretation of intervention efficacy.

OBJECTIVES

Characterize the proportion of infant neurodevelopment trials reporting a null finding and identify features that may contribute to a null result.

DATA SOURCES

The Cochrane library, Medline, Embase, and CINAHL databases.

STUDY SELECTION

Randomized controlled trials recruiting infants aged <6 months comparing any "infant-directed" intervention against standard care, placebo, or another intervention. Neurodevelopment assessed as the primary outcome between 12 months and 10 years of age using a defined list of tools.

DATA EXTRACTION

Two reviewers independently extracted data and assessed quality of included studies.

RESULTS

Of n = 1283 records screened, 21 studies (from 20 reports) were included. Of 18 superiority studies, >70% reported a null finding. Features were identified that may have contributed to the high proportion of null findings, including selection and timing of the primary outcome measure, anticipated effect size, sample size and power, and statistical analysis methodology and rigor.

LIMITATIONS

Publication bias against null studies means the proportion of null findings is likely underestimated. Studies assessing neurodevelopment as a secondary or within a composite outcome were excluded.

CONCLUSIONS

This review identified a high proportion of infant neurodevelopmental trials that produced a null finding and detected several methodological and design considerations which may have contributed. We make several recommendations for future trials, including more sophisticated approaches to trial design, outcome assessment, and analysis.

Are We Getting It Right? A Scoping Review of Outcomes Reported in Cell Therapy Clinical Studies for Cerebral Palsy

Cell therapies are an emergent treatment for cerebral palsy (CP) with promising evidence demonstrating efficacy for improving gross motor function. However, families value improvements in a range of domains following intervention and the non-motor symptoms, comorbidities and complications of CP can potentially be targeted by cell therapies. We conducted a scoping review to describe all outcomes that have been reported in cell therapy studies for CP to date, and to examine what instruments were used to capture these. Through a systematic search we identified 54 studies comprising 2066 participants that were treated with a range of cell therapy interventions. We categorized the reported 53 unique outcome instruments and additional descriptive measures into 10 categories and 12 sub-categories. Movement and Posture was the most frequently reported outcome category, followed by Safety, however Quality of Life, and various prevalent comorbidities and complications of CP were infrequently reported. Notably, many outcome instruments used do not have evaluative properties and thus are not suitable for measuring change following intervention. We provide a number of recommendations to ensure that future trials generate high-quality outcome data that is aligned with the priorities of the CP community.

Rehabilitation Evidence-Based Decision-Making: The READ Model

Evidence-based practice is the foundation of rehabilitation for maximizing client outcomes. However, an unacceptably high number of ineffective or outdated interventions are still implemented, leading to sub-optimal outcomes for clients. This paper proposes the Rehabilitation Evidence bAsed Decision-Making (READ) Model, a decision-making algorithm for evidence-based decision-making in rehabilitation settings. The READ Model outlines a step-by-step layered process for healthcare professionals to collaboratively set goals, and to select appropriate interventions. The READ Model acknowledges the important multi-layered contributions of client's preferences and values, family supports available, and external environmental factors such as funding, availability of services and access. Healthcare professionals can apply the READ Model to choose interventions that are evidence-based, with an appropriate mode, dose, and with regular review, in order to achieve client's goals. Two case studies are used to demonstrate application of the READ Model: cerebral palsy and autism spectrum disorder. The READ Model applies the four central principles of evidence-based practice and can be applied across multiple rehabilitation settings.

Safety of allogeneic umbilical cord blood infusions for the treatment of neurological conditions: a systematic review of clinical studies

BACKGROUND AIMS

Umbilical cord blood (UCB) infusion is being investigated as a treatment for a range of neurological conditions, primarily because of its potent immunomodulatory effects mediated via paracrine signaling. Although initial research mainly utilized autologous UCB, allogeneic samples from a sibling or unrelated donor have now become more common. With the use of allogeneic UCB, questions have arisen surrounding the necessity for human leukocyte antigen (HLA) matching, preparative regimens and immunosuppressant drugs. To investigate the safety of allogeneic UCB for the treatment of neurological conditions and the impact of HLA mismatching and immunosuppresion, the authors conducted a systematic review of the safety of allogeneic UCB infusion for neurological conditions.

METHODS

A systematic review of published and gray literature was conducted to investigate the safety of allogeneic UCB infusions for neurological conditions.

RESULTS

Authors identified 10 studies using allogeneic UCB to treat autism spectrum disorder, cerebral palsy, stroke, traumatic brain injury and various other conditions. A total of 361 participants (with at least 442 UCB infusions) received a range of HLA-matched/untyped allogeneic units and cell doses, with the majority not administered post-infusion immunosuppression. There were no reported serious adverse events definitely or probably related to the allogeneic UCB infusion, nor later potential complications such as graft-versus-host disease or teratoma formation.

CONCLUSIONS

Although variability between studies is high, the available data do not identify safety concerns with allogeneic UCB infusion for the treatment of neurological conditions, even with variable HLA matching or no immunosuppression.

Assessments and Interventions for Spasticity in Infants With or at High Risk for Cerebral Palsy: A Systematic Review

BACKGROUND

The majority of children with cerebral palsy develop spasticity, which interferes with motor development, function, and participation. This systematic review appraised current evidence regarding assessments and interventions for spasticity in children aged less than two years with or at high risk for cerebral palsy and integrated findings with parent preferences.

METHODS

Five databases (CINAHL, EMBASE, OVID/Medline, SCOPUS, and PsycINFO) were searched. Included articles were screened using PRISMA guidelines. Quality of the evidence was reviewed by two independent reviewers using Quality Assessment of Diagnostic Accuracy Studies, second edition (QUADAS-2), the RTI Item Bank on Risk of Bias and Precision of Observational Studies (RTI), or The Cochrane Collaboration's tool for assessing risk of bias in randomized trials (RoB). An online survey was conducted regarding parent preferences through social media channels.

RESULTS

Twelve articles met inclusion criteria. No high-quality assessment tool emerged for this population. Six interventions (botulinum toxin-A, orthotic use, radial extracorporeal shock wave therapy, erythropoietic stimulating agents, medical cannabis, and homeopathy) were identified. There was low-quality evidence for the use of botulinum toxin-A and radial extracorporeal shock wave therapy to improve short-term outcomes. Survey respondents indicated that spasticity assessments and interventions are highly valued, with nonpharmacologic interventions ranked most preferably.

CONCLUSIONS

Further research is needed to validate assessments for spasticity in children younger than two years. Conditional recommendations can be made for botulinum toxin-A and radial extracorporeal shock wave therapy based on low level of evidence to reduce spasticity in children aged less than two years.

Human Umbilical Cord Therapy Improves Long-Term Behavioral Outcomes Following Neonatal Hypoxic Ischemic Brain Injury

Background: Hypoxic ischemic (HI) insult in term babies at labor or birth can cause long-term neurodevelopmental disorders, including cerebral palsy (CP). The current standard treatment for term infants with hypoxic ischemic encephalopathy (HIE) is hypothermia. Because hypothermia is only partially effective, novel therapies are required to improve outcomes further. Human umbilical cord blood cells (UCB) are a rich source of stem and progenitor cells making them a potential treatment for neonatal HI brain injury. Recent clinical trials have shown that UCB therapy is a safe and efficacious treatment for confirmed cerebral palsy. In this study, we assessed whether early administration of UCB to the neonate could improve long-term behavioral outcomes and promote brain repair following neonatal HI brain injury. Methods: HI brain injury was induced in postnatal day (PND) 7 rat pups via permanent ligation of the left carotid artery, followed by a 90 min hypoxic challenge. UCB was administered intraperitoneally on PND 8. Behavioral tests, including negative geotaxis, forelimb preference and open field test, were performed on PND 14, 30, and 50, following brains were collected for assessment of neuropathology. Results: Neonatal HI resulted in decreased brain weight, cerebral tissue loss and apoptosis in the somatosensory cortex, as well as compromised behavioral outcomes. UCB administration following HI improved short and long-term behavioral outcomes but did not reduce long-term histological evidence of brain injury compared to HI alone. In addition, UCB following HI increased microglia activation in the somatosensory cortex compared to HI alone. Conclusion: Administration of a single dose of UCB cells 24 h after HI injury improves behavior, however, a single dose of cells does not modulate pathological evidence of long-term brain injury.

Human Umbilical Cord Blood Therapy Protects Cerebral White Matter from Systemic LPS Exposure in Preterm Fetal Sheep

BACKGROUND

Infants born preterm following exposure to in utero inflammation/chorioamnionitis are at high risk of brain injury and life-long neurological deficits. In this study, we assessed the efficacy of early intervention umbilical cord blood (UCB) cell therapy in a large animal model of preterm brain inflammation and injury. We hypothesised that UCB treatment would be neuroprotective for the preterm brain following subclinical fetal inflammation.

METHODS

Chronically instrumented fetal sheep at 0.65 gestation were administered lipopolysaccharide (LPS, 150 ng, 055:B5) intravenously over 3 consecutive days, followed by 100 million human UCB mononuclear cells 6 h after the final LPS dose. Controls were administered saline instead of LPS and cells. Ten days after the first LPS dose, the fetal brain and cerebrospinal fluid were collected for analysis of subcortical and periventricular white matter injury and inflammation.

RESULTS

LPS administration increased microglial aggregate size, neutrophil recruitment, astrogliosis and cell death compared with controls. LPS also reduced total oligodendrocyte count and decreased mature myelinating oligodendrocytes. UCB cell therapy attenuated cell death and inflammation, and recovered total and mature oligodendrocytes, compared with LPS.

CONCLUSIONS

UCB cell treatment following inflammation reduces preterm white matter brain injury, likely mediated via anti-inflammatory actions.

Effects of umbilical cord blood cells, and subtypes, to reduce neuroinflammation following perinatal hypoxic-ischemic brain injury

Background

It is well understood that hypoxic-ischemic (HI) brain injury during the highly vulnerable perinatal period can lead to cerebral palsy, the most prevalent cause of chronic disability in children. Recently, human clinical trials have reported safety and some efficacy following treatment of cerebral palsy using umbilical cord blood (UCB) cells. UCB is made up of many different cell types, including endothelial progenitor cells (EPCs), T regulatory cells (Tregs), and monocyte-derived suppressor cells (MDSCs). How each cell type contributes individually towards reducing neuroinflammation and/or repairing brain injury is not known. In this study, we examined whether human (h) UCB, or specific UCB cell types, could reduce peripheral and cerebral inflammation, and promote brain repair, when given early after perinatal HI brain injury.

Methods

HI brain injury was induced in postnatal day (PND) 7 rat pups and cells were administered intraperitoneally on PND 8. Behavioral testing was performed 7 days post injury, and then, brains and spleens were collected for analysis.

Results

We found in vitro that all UCB cell types, except for EPCs, were immunomodulatory. Perinatal HI brain injury induced significant infiltration of CD4+ T cells into the injured cerebral hemisphere, and this was significantly reduced by all hUCB cell types tested. Compared to HI, UCB, Tregs, and EPCs were able to reduce motor deficits, reduce CD4+ T cell infiltration into the brain, and reduce microglial activation. In addition to the beneficial effects of UCB, EPCs also significantly reduced cortical cell death, returned CD4+ T cell infiltration to sham levels, and reduced the peripheral Th1-mediated pro-inflammatory shift.

Conclusion

This study highlights that cells found in UCB is able to mediate neuroinflammation and is an effective neuroprotective therapy. Our study also shows that particular cells found in UCB, namely EPCs, may have an added advantage over using UCB alone. This work has the potential to progress towards tailored UCB therapies for the treatment of perinatal brain injury.

Perinatal Brain Injury As a Consequence of Preterm Birth and Intrauterine Inflammation: Designing Targeted Stem Cell Therapies

Chorioamnionitis is a major cause of preterm birth and brain injury. Bacterial invasion of the chorion and amnion, and/or the placenta, can lead to a fetal inflammatory response, which in turn has significant adverse consequences for the developing fetal brain. Accordingly, there is a strong causal link between chorioamnionitis, preterm brain injury and the pathogenesis of severe postnatal neurological deficits and cerebral palsy. Currently there are no treatments to protect or repair against brain injury in preterm infants born after pregnancy compromised by intrauterine infection. This review describes the injurious cascade of events in the preterm brain in response to a severe fetal inflammatory event. We will highlight specific periods of increased vulnerability, and the potential effects of therapeutic intervention with cell-based therapies. Many clinical trials are underway to investigate the efficacy of stem cells to treat patients with cerebral palsy. Stem cells, obtained from umbilical cord tissue and cord blood, normally discarded after birth, are emerging as a safe and potentially effective therapy. It is not yet known, however, which stem cell type(s) are the most efficacious for administration to preterm infants to treat brain injury-mediated inflammation. Individual stem cell populations found in cord blood and tissue, such as mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs), have a number of potential benefits that may specifically target preterm inflammatory-induced brain injury. MSCs have strong immunomodulatory potential, protecting against global and local neuroinflammatory cascades triggered during infection to the fetus. EPCs have angiogenic and vascular reparative qualities that make them ideal for neurovascular repair. A combined therapy using both MSCs and EPCs to target inflammation and promote angiogenesis for re-establishment of vital vessel networks is a treatment concept that warrants further investigation.

Cord blood mononuclear cells prevent neuronal apoptosis in response to perinatal asphyxia in the newborn lamb

Perinatal asphyxia is a significant cause of death or long-term neurodevelopmental impairment. Hypothermia, currently the only effective treatment, leads to modest improvements, but new therapeutic strategies are required. Umbilical cord blood (UCB) mononuclear cells have potent anti-inflammatory properties and may reduce neuropathology. This study examined whether autologous UCB mononuclear cells were neuroprotective when administered to newborn lambs at 12 h after birth asphyxia. At caesarean section, birth asphyxia was induced by clamping the umbilical cord until mean arterial blood pressure decreased to 18-20 mmHg. Asphyxia (n = 20) or control (n = 11) lambs were resuscitated and maintained, with magnetic resonance spectroscropy (MRS) performed at 12 and 72 h, and were then killed at 72 h. Cord blood was collected once the cord was clamped, and mononuclear cells were isolated and labelled fluorescently and administered to control (n = 3) or asphyxia (n = 8) lambs. Asphyxia induced a significant increase in cellular apoptosis (caspase-3 immunopositive) within all brain regions examined, including cortex, hippocampus, thalamus, striatum and subcortical white matter (P < 0.01 vs. control). Additionally, asphyxia induced significant and widespread astrogliosis and increased inflammatory cells (activated microglia and macrophages). The administration of UCB mononuclear cells (asphyxia+UCB) significantly decreased neuronal apoptosis, astrogliosis and inflammation (P < 0.05 vs. asphyxia alone). Asphyxia+UCB lambs also demonstrated decreased brain metabolites lactate:choline (P = 0.01) and lactate:N-acetylaspartate (P < 0.01) from 12 to 72 h, detected using MRS. Autologous UCB mononuclear cell treatment restores normal brain metabolism following perinatal asphyxia, and reduces brain inflammation, astrogliosis and neuronal apoptosis, supporting its use as a neuroprotective therapy following asphyxia.