Effects of intravenous administration of umbilical cord blood CD34(+) cells in a mouse model of neonatal stroke. Neuroscience. 2014;263:148-158. [PMID: 24444827 DOI: 10.1016/j.neuroscience.2014.01.018]

Long term outcomes of intracarotid arterial transfusion of circulatory-derived autologous CD34 + cells for acute ischemic stroke patients-A randomized, open-label, controlled phase II clinical trial

BACKGROUND

This phase II randomized controlled trial tested whether the intracarotid arterial administration (ICAA) of autologous CD34 + cells to patients within 14 ± 7 days after acute ischemic stroke (IS) could be safe and further improve short- and long-term outcomes.

METHODS

Between January 2018 and March 2022, 28 consecutive patients were equally randomly allocated to the cell-treated group (CD34 + cells/3.0 × 107/patient) or the control group (receiving optimal medical therapy). CD34 + cells were transfused into the ipsilateral brain infarct zone of cell-treated patients via the ICAA in the catheterization room.

RESULTS

The results demonstrated 100% safety and success rates for the procedure, and no long-term tumorigenesis was observed in cell-treated patients. In cell-treated patients, the angiogenesis capacity of circulating endothelial progenitor cells (EPCs)/Matrigel was significantly greater after treatment than before treatment with granulocyte colony-stimulating factor (all p < 0.001). Blood samples from the right internal jugular vein of the cell-treated patients presented significantly greater levels of the stromal cell-derived factor 1α/EPC at 5, 10 and 30 min compared with 0 min (all p < 0.005). The National Institute of Health Stroke Scale scores were similar upon presentation, but a greater response was observed by Days 30 and 90 in the cell-treated group than in the control group. Tc-99 m brain perfusion was significantly greater at 180 days in the cell-treated group than in the control group (p = 0.046). The combined long-term end points (defined as death/recurrent stroke/or severe disability) were notably lower in the control group compared with the cell-treated group (14.3% vs. 50.0%, p = 0.103).

CONCLUSION

Intracarotid transfusion of autologous CD34 + cells is safe and might improve long-term outcomes in patients with acute IS. Trial registration ISRCTN, ISRCTN15677760. Registered 23 April 2018- Retrospectively registered, https://doi.org/10.1186/ISRCTN15677760.

Safety and tolerability of a Muse cell-based product in neonatal hypoxic-ischemic encephalopathy with therapeutic hypothermia (SHIELD trial)

Hypoxic-ischemic encephalopathy (HIE), associated with high mortality and neurological sequelae, lacks established treatment except therapeutic hypothermia. Clinical-grade multilineage-differentiating stress-enduring (Muse) cells (CL2020) demonstrated safety and efficacy in nonclinical HIE rat models, thereby leading to an investigator-initiated clinical trial to evaluate CL2020 safety and tolerability in neonatal HIE as a single-center open-label dose-escalation study with 9 neonates with moderate-to-severe HIE who received therapeutic hypothermia. Each patient received a single intravenous injection of CL2020 cells between 5 and 14 days of age. The low-dose (3 patients) and high-dose (6 patients) groups received 1.5 × 106 and 1.5 × 107 cells/dose, respectively. The occurrence of any adverse event within 12 weeks following CL2020 administration was the primary endpoint of this trial. No significant changes in physiological signs including heart rate, blood pressure, and oxygen saturation were observed during or after administration. The only adverse event that may be related to cell administration was a mild γ-glutamyltransferase level elevation in one neonate, which spontaneously resolved without any treatment. All patients enrolled in the trial survived, and normal developmental quotients (≥ 85) in all 3 domains of the Kyoto Scale of Psychological Development 2001 were observed in 67% of the patients in this trial. CL2020 administration was demonstrated to be safe and tolerable for neonates with HIE. Considering the small number of patients, a randomized controlled confirmatory study is warranted to verify these preliminary findings and evaluate the efficacy of this therapy.

Umbilical cord blood derived cell expansion: a potential neuroprotective therapy

Umbilical cord blood (UCB) is a rich source of beneficial stem and progenitor cells with known angiogenic, neuroregenerative and immune-modulatory properties. Preclinical studies have highlighted the benefit of UCB for a broad range of conditions including haematological conditions, metabolic disorders and neurological conditions, however clinical translation of UCB therapies is lacking. One barrier for clinical translation is inadequate cell numbers in some samples meaning that often a therapeutic dose cannot be achieved. This is particularly important when treating adults or when administering repeat doses of cells. To overcome this, UCB cell expansion is being explored to increase cell numbers. The current focus of UCB cell expansion is CD34+ haematopoietic stem cells (HSCs) for which the main application is treatment of haematological conditions. Currently there are 36 registered clinical trials that are examining the efficacy of expanded UCB cells with 31 of these being for haematological malignancies. Early data from these trials suggest that expanded UCB cells are a safe and feasible treatment option and show greater engraftment potential than unexpanded UCB. Outside of the haematology research space, expanded UCB has been trialled as a therapy in only two preclinical studies, one for spinal cord injury and one for hind limb ischemia. Proteomic analysis of expanded UCB cells in these studies showed that the cells were neuroprotective, anti-inflammatory and angiogenic. These findings are also supported by in vitro studies where expanded UCB CD34+ cells showed increased gene expression of neurotrophic and angiogenic factors compared to unexpanded CD34+ cells. Preclinical evidence demonstrates that unexpanded CD34+ cells are a promising therapy for neurological conditions where they have been shown to improve multiple indices of injury in rodent models of stroke, Parkinson's disease and neonatal hypoxic ischemic brain injury. This review will highlight the current application of expanded UCB derived HSCs in transplant medicine, and also explore the potential use of expanded HSCs as a therapy for neurological conditions. It is proposed that expanded UCB derived CD34+ cells are an appropriate cellular therapy for a range of neurological conditions in children and adults.

The therapeutic role of SSEA3(+) human umbilical cord blood mononuclear cells in ischemic stroke model

Numerous evidences showed that human umbilical cord blood (UCB) mononuclear cells were a promising approach for the therapy of ischemic stroke(IS). The effect of stage-specific embryonic antigen 3 (SSEA3）positive subpopulation in UCB was not investigated in IS. In this study, we isolated SSEA3 positive cells from healthy UCB mononuclear cells, which comprised about 7.01% of the total UCB-mononuclear cells. Flow cytometry analysis revealed that SSEA3(+)UCB cells were almost positive for CD44 and CD45, and negative for CD73, CD90 and CD105. The expression of Oct3/4 in SSEA3(+)UCB cells were higher than that in UCB. SSEA3(+)UCB cells sorted by magnetic cell sorting were intravenously injected into the middle cerebral arterial occlusion(MCAO) rat model. Neurological score showed that SSEA3(+)UCB transplantation group exhibited significant improvements in the functional outcome of MCAO rats than UCB transplantation group. Nissl staining and microtubule association protein-2(MAP2) immunofluorescence staining showed that the SSEA3(+)UCB transplantation group decreased neuronal loss. SSEA3(+)UCB transplantation group reduced neuronal apoptosis, inhibited caspase3 expression, and decreased tumor necrosis factor α(TNF-α). These results indicate that SSEA3 positive cells are a novel subpopulation of UCB cells, which exhibit great potential for the treatment of ischemic stroke.

Targeting the Multiple Complex Processes of Hypoxia-Ischemia to Achieve Neuroprotection

Hypoxic-ischemic encephalopathy (HIE) is a major cause of newborn brain damage stemming from a lack of oxygenated blood flow in the neonatal period. Twenty-five to fifty percent of asphyxiated infants who develop HIE die in the neonatal period, and about sixty percent of survivors develop long-term neurological disabilities. From the first minutes to months after the injury, a cascade of events occurs, leading to blood-brain barrier (BBB) opening, neuronal death and inflammation. To date, the only approach proposed in some cases is therapeutic hypothermia (TH). Unfortunately, TH is only partially protective and is not applicable to all neonates. This review synthesizes current knowledge on the basic molecular mechanisms of brain damage in hypoxia-ischemia (HI) and on the different therapeutic strategies in HI that have been used and explores a major limitation of unsuccessful therapeutic approaches.

Stem cell-based interventions for the treatment of stroke in newborn infants

BACKGROUND

Perinatal stroke refers to a diverse but specific group of cerebrovascular diseases that occur between 20 weeks of fetal life and 28 days of postnatal life. Acute treatment options for perinatal stroke are limited supportive care, such as controlling hypoglycemia and seizures. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, or regenerate injured brain tissue. Preclinical findings have culminated in ongoing human neonatal studies.

OBJECTIVES

To evaluate the benefits and harms of stem cell-based interventions for the treatment of stroke in newborn infants compared to control (placebo or no treatment) or stem-cell based interventions of a different type or source.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, and three trials registries in February 2023. We planned to search the reference lists of included studies and relevant systematic reviews for studies not identified by the database searches.

SELECTION CRITERIA

We attempted to include randomized controlled trials, quasi-randomized controlled trials, and cluster trials that evaluated any of the following comparisons. • Stem cell-based interventions (any type) versus control (placebo or no treatment) • Mesenchymal stem/stromal cells (MSCs) of a specifictype (e.g. number of doses or passages) or source (e.g. autologous/allogeneic or bone marrow/cord) versus MSCs of another type or source • Stem cell-based interventions (other than MSCs) of a specific type (e.g. mononuclear cells, oligodendrocyte progenitor cells, neural stem cells, hematopoietic stem cells, or induced pluripotent stem cell-derived cells) or source (e.g. autologous/allogeneic or bone marrow/cord) versus stem cell-based interventions (other than MSCs) of another type or source • MSCs versus stem cell-based interventions other than MSCs We planned to include all types of transplantation regardless of cell source (bone marrow, cord blood, Wharton's jelly, placenta, adipose tissue, peripheral blood), type of graft (autologous or allogeneic), and dose.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were all-cause neonatal mortality, major neurodevelopmental disability, and immune rejection or any serious adverse event. Our secondary outcomes included all-cause mortality prior to first hospital discharge, seizures, adverse effects, and death or major neurodevelopmental disability at 18 to 24 months of age. We planned to use GRADE to assess the certainty of evidence for each outcome.

MAIN RESULTS

We identified no completed or ongoing randomized trials that met our inclusion criteria. We excluded three studies: two were phase 1 trials, and one included newborn infants with conditions other than stroke (i.e. cerebral ischemia and anemia). Among the three excluded studies, we identified the first phase 1 trial on the use of stem cells for neonatal stroke. It reported that a single intranasal application of bone marrow-derived MSCs in term neonates with a diagnosis of perinatal arterial ischemic stroke (PAIS) was feasible and apparently not associated with severe adverse events. However, the trial included only 10 infants, and follow-up was limited to three months.

AUTHORS' CONCLUSIONS

No evidence is currently available to evaluate the benefits and harms of stem cell-based interventions for treatment of stroke in newborn infants. We identified no ongoing studies. Future clinical trials should focus on standardizing the timing and method of cell delivery and cell processing to optimize the therapeutic potential of stem cell-based interventions and safety profiles. Phase 1 and large animal studies might provide the groundwork for future randomized trials. Outcome measures should include all-cause mortality, major neurodevelopmental disability and immune rejection, and any other serious adverse events.

Monocytes in neonatal stroke and hypoxic‐ischemic encephalopathy: Pathophysiological mechanisms and therapeutic possibilities

Neonatal arterial ischemic stroke (NAIS) and neonatal hypoxic‐ischemic encephalopathy (HIE) are common causes of neurological impairments in infants, for which treatment options are very limited. NAIS and HIE induce an innate immune response that involves the recruitment of peripheral immune cells, including monocytes, into the brain. Monocytes and monocyte‐derived cells have the potential to contribute to both harmful and beneficial pathophysiological processes, such as neuroinflammation and brain repair, but their roles in NAIS and HIE remain poorly understood. Furthermore, recent evidence indicates that monocyte‐derived macrophages can persist in the brain for several months following NAIS and HIE in mice, with possible long‐lasting consequences that are still unknown. This review provides a comprehensive overview of the mechanisms of monocyte infiltration and their potential functions in the ischemic brain, focusing on HIE and NAIS. Therapeutic strategies targeting monocytes and the possibility of using monocytes for cell‐based therapies are also discussed.

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.

Stem cell‐based interventions for the treatment of stroke in newborn infants

This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the benefits and harms of stem cell‐based interventions for the treatment of stroke in newborn infants compared to control (placebo or no treatment) or stem‐cell based interventions of a different type or source.

Stem cell-based interventions for the prevention and treatment of intraventricular haemorrhage and encephalopathy of prematurity in preterm infants

BACKGROUND

Germinal matrix-intraventricular haemorrhage (GMH-IVH) and encephalopathy of prematurity (EoP) remain substantial issues in neonatal intensive care units worldwide. Current therapies to prevent or treat these conditions are limited. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal studies. This is an update of the 2019 review, which did not include EoP.

OBJECTIVES

To evaluate the benefits and harms of stem cell-based interventions for prevention or treatment of GM-IVH and EoP in preterm infants.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search was April 2022.

SELECTION CRITERIA

We attempted to include randomised controlled trials, quasi-randomised controlled trials, and cluster trials comparing 1. stem cell-based interventions versus control; 2. mesenchymal stromal cells (MSCs) of type or source versus MSCs of other type or source; 3. stem cell-based interventions other than MSCs of type or source versus stem cell-based interventions other than MSCs of other type or source; or 4. MSCs versus stem cell-based interventions other than MSCs. For prevention studies, we included extremely preterm infants (less than 28 weeks' gestation), 24 hours of age or less, without ultrasound diagnosis of GM-IVH or EoP; for treatment studies, we included preterm infants (less than 37 weeks' gestation), of any postnatal age, with ultrasound diagnosis of GM-IVH or with EoP.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. all-cause neonatal mortality, 2. major neurodevelopmental disability, 3. GM-IVH, 4. EoP, and 5. extension of pre-existing non-severe GM-IVH or EoP. We planned to use GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We identified no studies that met our inclusion criteria. Three studies are currently registered and ongoing. Phase 1 trials are described in the 'Excluded studies' section.

AUTHORS' CONCLUSIONS

No evidence is currently available to evaluate the benefits and harms of stem cell-based interventions for treatment or prevention of GM-IVH or EoP in preterm infants. We identified three ongoing studies, with a sample size range from 20 to 200. In two studies, autologous cord blood mononuclear cells will be administered to extremely preterm infants via the intravenous route; in one, intracerebroventricular injection of MSCs will be administered to preterm infants up to 34 weeks' gestational age.

Neonatal asphyxia as an inflammatory disease: Reactive oxygen species and cytokines

Neonatologists resuscitate asphyxiated neonates by every available means, including positive ventilation, oxygen therapy, and drugs. Asphyxiated neonates sometimes present symptoms that mimic those of inflammation, such as fever and edema. The main pathophysiology of the asphyxia is inflammation caused by hypoxic-ischemic reperfusion. At birth or in the perinatal period, neonates may suffer several, hypoxic insults, which can activate inflammatory cells and inflammatory mediator production leading to the release of larger quantities of reactive oxygen species (ROS). This in turn triggers the production of oxygen stress-induced high mobility group box-1 (HMGB-1), an endogenous damage-associated molecular patterns (DAMPs) protein bound to toll-like receptor (TLR) -4, which activates nuclear factor-kappa B (NF-κB), resulting in the production of excess inflammatory mediators. ROS and inflammatory mediators are produced not only in activated inflammatory cells but also in non-immune cells, such as endothelial cells. Hypothermia inhibits pro-inflammatory mediators. A combination therapy of hypothermia and medications, such as erythropoietin and melatonin, is attracting attention now. These medications have both anti-oxidant and anti-inflammatory effects. As the inflammatory response and oxidative stress play a critical role in the pathophysiology of neonatal asphyxia, these drugs may contribute to improving patient outcomes.

CD34 positive cells as endothelial progenitor cells in biology and medicine

CD34 is a cell surface antigen expressed in numerous stem/progenitor cells including hematopoietic stem cells (HSCs) and endothelial progenitor cells (EPCs), which are known to be rich sources of EPCs. Therefore, regenerative therapy using CD34⁺ cells has attracted interest for application in patients with various vascular, ischemic, and inflammatory diseases. CD34⁺ cells have recently been reported to improve therapeutic angiogenesis in a variety of diseases. Mechanistically, CD34⁺ cells are involved in both direct incorporation into the expanding vasculature and paracrine activity through angiogenesis, anti-inflammatory, immunomodulatory, and anti-apoptosis/fibrosis roles, which support the developing microvasculature. Preclinical, pilot, and clinical trials have well documented a track record of safety, practicality, and validity of CD34⁺ cell therapy in various diseases. However, the clinical application of CD34⁺ cell therapy has triggered scientific debates and controversies in last decade. This review covers all preexisting scientific literature and prepares an overview of the comprehensive biology of CD34⁺ cells as well as the preclinical/clinical details of CD34⁺ cell therapy for regenerative medicine.

A Systematic Review of CD34+ Stem Cell Therapy as an Innovative and Efficient Treatment for the Management of Refractory Angina

Despite optimal medical treatment, many individuals suffering from severe coronary artery disease are not suitable candidates for further revascularization. Therapeutic angiogenesis has attracted continuous interest to increase myocardial perfusion. Cell therapy using autologous stem cells expressing Cluster of Differentiation 34 plus (CD34+) offers a special therapeutic choice for individuals with refractory angina, seeing as CD34+ stem cells can restore microcirculation. We searched PubMed, PubMed Central (PMC), and Google Scholar to find the relevant articles to write this systematic review about the role of CD34+ stem cell therapy in the management of refractory angina. Additionally, we provided a brief explanation of CD34+ cells and their mechanism of action. Along with the positive finding of other trials, a recent open-label, single-center intracoronary CD34+ cell therapy for the treatment of coronary endothelial dysfunction in patients with angina and nonobstructive coronary arteries (IMPROvE-CED) clinical trial published in 2022 concluded improvement in coronary blood flow, a significant reduction in daily as-needed sublingual nitroglycerin use and improvement in Canadian Cardiovascular Society (CCS) angina class were observed after autologous CD34+ cell treatment. In conclusion, refractory angina management and overall prognosis may be revolutionized once this treatment is approved.

Human umbilical cord blood mononuclear cells transplantation for perinatal brain injury

Perinatal brain injury is a leading cause of death and disability in children. Hypoxic-ischemic encephalopathy in full term infants, and white matter injury in premature infants are most known brain injury in perinatal period. Human umbilical cord blood mononuclear cells contain hematopoietic stem cells, mesenchymal stem cells, endothelial progenitor cells, lymphocytes, monocytes, and so on. Human umbilical cord blood mononuclear cells have many biological functions, such as nerve and vascular regeneration, anti-apoptosis, anti-inflammation, and immune regulation. Human umbilical cord blood mononuclear cells transplantation has achieved significant efficacy and safety in animal and clinical trials for the treatment of perinatal brain injury. We will review human umbilical cord blood mononuclear cells transplantation for perinatal brain injury in this review.

Rationale for the Use of Cord Blood in Hypoxic-Ischaemic Encephalopathy

Hypoxic-ischaemic encephalopathy (HIE) is a severe complication of asphyxia at birth. Therapeutic hypothermia, the standard method for HIE prevention, is effective in only 50% of the cases. As the understanding of the immunological basis of these changes increases, experiments have begun with the use of cord blood (CB) because of its neuroprotective properties. Mechanisms for the neuroprotective effects of CB stem cells include antiapoptotic and anti-inflammatory actions, stimulation of angiogenesis, production of trophic factors, and mitochondrial donation. In several animal models of HIE, CB decreased oxidative stress, cell death markers, CD4+ T cell infiltration, and microglial activation; restored normal brain metabolic activity; promoted neurogenesis; improved myelination; and increased the proportion of mature oligodendrocytes, neuron numbers in the motor cortex and somatosensory cortex, and brain weight. These observations translate into motor strength, limb function, gait, and cognitive function and behaviour. In humans, the efficacy and safety of CB administration were reported in a few early clinical studies which confirmed the feasibility and safety of this intervention for up to 10 years. The results of these studies showed an improvement in the developmental outcomes over hypothermia. Two phase-2 clinical studies are ongoing under the United States regulations, namely one controlled study and one blinded study.

Safety and tolerability of a multilineage-differentiating stress-enduring cell-based product in neonatal hypoxic-ischaemic encephalopathy with therapeutic hypothermia (SHIELD trial): a clinical trial protocol open-label, non-randomised, dose-escalation trial

INTRODUCTION

Neonatal hypoxic-ischaemic encephalopathy (HIE) is an important illness associated with death or cerebral palsy. This study aims to assess the safety and tolerability of the allogenic human multilineage-differentiating stress-enduring cell (Muse cell)-based product (CL2020) cells in newborns with HIE. This is the first clinical trial of CL2020 cells in neonates.

METHODS AND ANALYSIS

This is a single-centre, open-label, dose-escalation study enrolling up to 12 patients. Neonates with HIE who receive a course of therapeutic hypothermia therapy, which cools to a body temperature of 33°C-34°C for 72 hours, will be included in this study. A single intravenous injection of CL2020 cells will be administered between 5 and 14 days of age. Subjects in the low-dose and high-dose cohorts will receive 1.5 and 15 million cells per dose, respectively. The primary outcome is the occurrence of any adverse events within 12 weeks after administration. The main secondary outcome is the Bayley Scales of Infant and Toddler Development Third Edition score and the developmental quotient per the Kyoto Scale of Psychological Development 2001 at 78 weeks.

ETHICS AND DISSEMINATION

This study will be conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. The Nagoya University Hospital Institutional Review Board (No. 312005) approved this study on 13 November 2019. The results of this study will be published in peer-reviewed journal and reported in international conferences.

TRIAL REGISTRATION NUMBERS

NCT04261335, jRCT2043190112.

Therapies for neonatal encephalopathy: Targeting the latent, secondary and tertiary phases of evolving brain injury

In term and near-term neonates with neonatal encephalopathy, therapeutic hypothermia protocols are well established. The current focus is on how to improve outcomes further and the challenge is to find safe and complementary therapies that confer additional protection, regeneration or repair in addition to cooling. Following hypoxia-ischemia, brain injury evolves over three main phases (latent, secondary and tertiary), each with a different brain energy, perfusion, neurochemical and inflammatory milieu. While therapeutic hypothermia has targeted the latent and secondary phase, we now need therapies that cover the continuum of brain injury that spans hours, days, weeks and months after the initial event. Most agents have several therapeutic actions but can be broadly classified under a predominant action (e.g., free radical scavenging, anti-apoptotic, anti-inflammatory, neuroregeneration, and vascular effects). Promising early/secondary phase therapies include Allopurinol, Azithromycin, Exendin-4, Magnesium, Melatonin, Noble gases and Sildenafil. Tertiary phase agents include Erythropoietin, Stem cells and others. We review a selection of promising therapeutic agents on the translational pipeline and suggest a framework for neuroprotection and neurorestoration that targets the evolving injury.

Diverse actions of cord blood cell therapy for hypoxic-ischemic encephalopathy

Perinatal hypoxic-ischemic encephalopathy (HIE) is a major cause of neonatal death and permanent neurological deficits. However, effective treatments have not yet been established, except therapeutic hypothermia, which is not effective for severe HIE; therefore, developing a novel therapy for HIE is of the utmost importance. Stem cell therapy has recently been identified as a novel therapy for HIE. Among the various stem cell sources, ethical hurdles can be avoided by using stem cells that originate from non-embryonic or non-neural tissues, such as umbilical cord blood cells (UCBCs), which are readily available and can be exploited for autologous transplantations. Human UCBs are a rich source of stem and progenitor cells. Many recent studies have reported the treatment effect of UCBCs. Additionally, phase I clinical trials have already been conducted, showing this therapy's safety and feasibility. One advantage of stem cell therapies, including UCBC administration, is that they exert treatment effects through multifaceted mechanisms. According to the findings of several publications, replacement of lost cells, namely, engraftment and differentiation into neuronal cells, is not likely to be the main mechanism. However, the association between UCBCs and various mechanism of action, such as neurogenesis, angiogenesis, and anti-inflammation, has been suggested in many studies, and most mechanisms are due to growth factors secreted from UCBCs. These diverse actions of UCBC treatment are expected to exert a substantial effect on HIE, which has a complex injury mechanism.

Therapeutic potential of stem cells for preterm infant brain damage: Can we move from the heterogeneity of preclinical and clinical studies to established therapeutics?

Acquired perinatal brain injuries are a set of conditions that remains a key challenge for neonatologists and that have significant social, emotional and financial implications for our communities. In our perspective article, we will introduce perinatal brain injury focusing specifically on the events leading to brain damage in preterm born infants and outcomes for these infants. Then we will summarize and discuss the preclinical and clinical studies testing the efficacy of stem cells as neuroprotectants in the last ten years in perinatal brain injury. There are no therapies to treat brain damage in preterm born infants and a primary finding from this review is that there is a scarcity of stem cell trials focused on overcoming brain injuries in these infants. Overall, across all forms of perinatal brain injury there is a remarkable heterogeneity in previous and on-going preclinical and clinical studies in terms of the stem cell type, animal models/patient selection, route and time of administration. Despite the quality of many of the studies this variation makes it difficult to reach a valid consensus for future developments. However, it is clear that stem cells (and stem cell derived exosomes) can reduce perinatal brain injury and our field needs to work collectively to refine an effective protocol for each type of injury. The use of standardized stem cell products and testing these products across multiple models of injury will provide a stronger framework for clinical trials development.

Brain damage caused by neonatal hypoxia-ischemia and the effects of hypothermia in severe combined immunodeficient (SCID) mice

Neonatal hypoxic-ischemic encephalopathy (HIE) is a major cause of brain damage in newborns. Although therapeutic hypothermia has been shown to be neuroprotective against neonatal HIE in clinical trials, its effect is not satisfactory. Cell-based therapies have attracted much attention as novel treatments for HIE. Preclinical studies on a variety of human cell transplantation methods have been performed in immunodeficient/immunosuppressed animals, such as severe combined immunodeficient (SCID) mice, which lack functional T and B lymphocytes. The detailed characteristics of neonatal HIE in SCID mice, however, have not been delineated. In preclinical studies, novel therapies for neonatal HIE should be evaluated in combination with hypothermia, which has become a standard treatment for neonatal HIE. However, the effects of hypothermia in SCID mice have not been delineated. In the present study, we compared neonatal hypoxic-ischemic (HI) brain damage in SCID mice and wild-type mice treated with or without hypothermia. Male and female mouse pups were subjected to HI insult induced by unilateral common carotid artery ligation combined with systemic hypoxia on postnatal day 12. In the first 4 h after HI insult, body temperature was maintained at 36 °C for the normothermia groups or 32 °C for the hypothermia groups. The severity of brain damage in SCID mice did not differ from that in wild-type mice based on most evaluations, i.e., cerebral blood flow, hemiparesis, muscle strength, spontaneous activity, cerebral hemispheric volume, neuropathological injury, and serum cytokine levels, although spleen weight, brain weight, leukocyte counts and the levels of some cytokines in the peripheral blood were different between genotypes. The effects of hypothermia in SCID mice were comparable to those in wild-type mice based on most evaluations. Taken together, these findings indicate that SCID mice can be used as an appropriate preclinical model for cell therapies for neonatal HIE.

Metabolomic analysis and mass spectrometry imaging after neonatal stroke and cell therapies in mouse brains

Ischemic brain injury provokes complex, time-dependent downstream pathways that ultimately lead to cell death. We aimed to demonstrate the levels of a wide range of metabolites in brain lysates and their on-tissue distribution following neonatal stroke and cell therapies. Postnatal day 12 mice underwent middle cerebral artery occlusion (MCAO) and were administered 1 × 10⁵ cells after 48 h. Metabolomic analysis of the injured hemisphere demonstrated that a variety of amino acids were significantly increased and that tricarboxylic acid cycle intermediates and some related amino acids, such as glutamate, were decreased. With the exception of the changes in citric acid, neither mesenchymal stem/stromal cells nor CD34⁺ cells ameliorated these changes. On-tissue visualization with matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging revealed that the signal intensity of glutamate was significantly decreased in the infarct area, consistent with the metabolomic analysis, while its intensity was significantly increased in the peri-infarct area after MCAO. Although cell therapies did not ameliorate the changes in metabolites in the infarct area, mesenchymal stem cells ameliorated the increased levels of glutamate and carnitine in the peri-infarct area. MALDI-MS imaging showed the location-specific effect of cell therapies even in this subacute setting after MCAO. These methodologies may be useful for further investigation of possible treatments for ischemic brain injury.

Umbilical cord blood cells for the treatment of preterm white matter injury: Potential effects and treatment options

Preterm birth is a global public health problem. A large number of preterm infants survive with preterm white matter injury (PWMI), which leads to neurological deficits, and has multifaceted etiology, clinical course, monitoring, and outcomes. The principal upstream insults leading to PWMI initiation are hypoxia-ischemia and infection and/or inflammation and the key target cells are late oligodendrocyte precursor cells. Current PWMI treatments are mainly supportive, and thus have little effect in terms of protecting the immature brain or repairing injury to improve long-term outcomes. Umbilical cord blood (UCB) cells comprise abundant immunomodulatory and stem cells, which have the potential to reduce brain injury, mainly due to anti-inflammatory and immunomodulatory mechanisms, and also through their release of neurotrophic or growth factors to promote endogenous neurogenesis. In this review, we briefly summarize PWMI pathogenesis and pathophysiology, and the specific properties of different cell types in UCB. We further explore the potential mechanism by which UCB can be used to treat PWMI, and discuss the advantages of and potential issues related to UCB cell therapy. Finally, we suggest potential future studies of UCB cell therapy in preterm infants.

Stem cell-based interventions for the prevention of morbidity and mortality following hypoxic-ischaemic encephalopathy in newborn infants

BACKGROUND

Hypoxic-ischaemic encephalopathy (HIE) is a leading cause of mortality and long-term neurological sequelae, affecting thousands of children worldwide. Current therapies to treat HIE are limited to cooling. Stem cell-based therapies offer a potential therapeutic approach to repair or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal trials.

OBJECTIVES

To determine the efficacy and safety of stem cell-based interventions for the treatment of hypoxic-ischaemic encephalopathy (HIE) in newborn infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 5), MEDLINE via PubMed (1966 to 8 June 2020), Embase (1980 to 8 June 2020), and CINAHL (1982 to 8 June 2020). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised controlled trials, quasi-randomised controlled trials and cluster trials comparing 1) stem cell-based interventions (any type) compared to control (placebo or no treatment); 2) use of mesenchymal stem/stromal cells (MSCs) of type (e.g. number of doses or passages) or source (e.g. autologous versus allogeneic, or bone marrow versus cord) versus MSCs of other type or source; 3) use of stem cell-based interventions other than MSCs of type (e.g. mononuclear cells, oligodendrocyte progenitor cells, neural stem cells, hematopoietic stem cells, and inducible pluripotent stem cells) or source (e.g. autologous versus allogeneic, or bone marrow versus cord) versus stem cell-based interventions other than MSCs of other type or source; or 4) MSCs versus stem cell-based interventions other than MSCs.

DATA COLLECTION AND ANALYSIS

For each of the included trials, two authors independently planned to extract data (e.g. number of participants, birth weight, gestational age, type and source of MSCs or other stem cell-based interventions) and assess the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). The primary outcomes considered in this review are all-cause neonatal mortality, major neurodevelopmental disability, death or major neurodevelopmental disability assessed at 18 to 24 months of age. We planned to use the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Our search strategy yielded 616 references. Two review authors independently assessed all references for inclusion. We did not find any completed studies for inclusion. Fifteen RCTs are currently registered and ongoing. We describe the three studies we excluded.

AUTHORS' CONCLUSIONS

There is currently no evidence from randomised trials that assesses the benefit or harms of stem cell-based interventions for the prevention of morbidity and mortality following hypoxic-ischaemic encephalopathy in newborn infants.

Autologous cord blood cell therapy for neonatal hypoxic-ischaemic encephalopathy: a pilot study for feasibility and safety

Neonatal hypoxic-ischaemic encephalopathy (HIE) is a serious condition; many survivors develop neurological impairments, including cerebral palsy and intellectual disability. Preclinical studies show that the systemic administration of umbilical cord blood cells (UCBCs) is beneficial for neonatal HIE. We conducted a single-arm clinical study to examine the feasibility and safety of intravenous infusion of autologous UCBCs for newborns with HIE. When a neonate was born with severe asphyxia, the UCB was collected, volume-reduced, and divided into three doses. The processed UCB was infused at 12–24, 36–48, and 60–72 hours after the birth. The designed enrolment was six newborns. All six newborns received UCBC therapy strictly adhering to the study protocol together with therapeutic hypothermia. The physiological parameters and peripheral blood parameters did not change much between pre- and postinfusion. There were no serious adverse events that might be related to cell therapy. At 30 days of age, the six infants survived without circulatory or respiratory support. At 18 months of age, neurofunctional development was normal without any impairment in four infants and delayed with cerebral palsy in two infants. This pilot study shows that autologous UCBC therapy is feasible and safe.

Therapeutic mechanism of cord blood mononuclear cells via the IL-8-mediated angiogenic pathway in neonatal hypoxic-ischaemic brain injury

In a clinical trial of cerebral palsy, the level of plasma interleukin-8 (IL-8) was increased, correlated with motor improvement, after human umbilical cord blood mononuclear cell (hUCBC) infusion. This study aimed to elucidate the role of IL-8 in the therapeutic effects of hUCBCs in a mouse model of hypoxic-ischaemic brain injury (HI). In P7 HI mouse brains, hUCBC administration at day 7 after HI upregulated the gene expression of Cxcl2, the mouse IL-8 homologue and increased the expression of its receptor, CXCR2. hUCBC administration restored the sequential downstream signalling axis of p-p38/p-MAPKAPK2, NFκB, and angiogenic factors, which were downregulated by HI. An in vitro assay revealed the downregulation of the angiogenic pathway by CXCR2 knockdown and p38 inhibition. In vivo p38 inhibition prior to hUCBC administration in HI mouse brains produced identical results. Behavioural outcomes revealed a therapeutic effect (ps < 0.01) of hUCBC or IL-8 administration, which was correlated with decreases in infarct size and angiogenic findings in the striatum. In conclusion, the response of the host to hUCBC administration in mice upregulated Cxcl2, which led to the activation of the IL-8-mediated p-p38 signalling pathway. The upregulation of the downstream pathway and angiogenic growth factors via NFκB can be inferred to be the potential therapeutic mechanism of hUCBCs.

Neurovascular effects of umbilical cord blood-derived stem cells in growth-restricted newborn lambs : UCBCs for perinatal brain injury

Background

Neonatal ventilation exacerbates brain injury in lambs with fetal growth restriction (FGR), characterized by neuroinflammation and reduced blood-brain barrier integrity, which is normally maintained by the neurovascular unit. We examined whether umbilical cord blood stem cell (UCBC) treatment stabilized the neurovascular unit and reduced brain injury in preterm ventilated FGR lambs.

Methods

Surgery was performed in twin-bearing pregnant ewes at 88 days’ gestation to induce FGR in one fetus. At 127 days, FGR and appropriate for gestational age (AGA) lambs were delivered, carotid artery flow probes and umbilical lines inserted, lambs intubated and commenced on gentle ventilation. Allogeneic ovine UCBCs (25 × 10⁶ cells/kg) were administered intravenously to lambs at 1 h of life. Lambs were ventilated for 24 h and then euthanized.

Results

FGR (n = 6) and FGR+UCBC (n = 6) lambs were growth restricted compared to AGA (n = 6) and AGA+UCBC (n = 6) lambs (combined weight, FGR 2.3 ± 0.4 vs. AGA 3.0 ± 0.3 kg; p = 0.0002). UCBC therapy did not alter mean arterial blood pressure or carotid blood flow but decreased cerebrovascular resistance in FGR+UCBC lambs. Circulating TNF-α cytokine levels were lower in FGR+UCBC vs. FGR lambs (p < 0.05). Brain histopathology showed decreased neuroinflammation and oxidative stress, increased endothelial cell proliferation, pericyte stability, and greater integrity of the neurovascular unit in FGR+UCBC vs. FGR lambs.

Conclusions

Umbilical cord blood stem cell therapy mitigates perinatal brain injury due to FGR and ventilation, and the neuroprotective benefits may be mediated by stabilization of the neurovascular unit.

Stem cell-based interventions for the prevention and treatment of germinal matrix-intraventricular haemorrhage in preterm infants

BACKGROUND

Germinal matrix-intraventricular haemorrhage (GMH-IVH) remains a substantial issue in neonatal intensive care units worldwide. Current therapies to prevent or treat GMH-IVH are limited. Stem cell-based therapies offer a potential therapeutic approach to repair, restore, and/or regenerate injured brain tissue. These preclinical findings have now culminated in ongoing human neonatal studies.

OBJECTIVES

To determine the benefits and harms of stem cell-based interventions for prevention or treatment of germinal matrix-intraventricular haemorrhage (GM-IVH) in preterm infants.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 1), in the Cochrane Library; MEDLINE via PubMed (1966 to 7 January 2019); Embase (1980 to 7 January 2019); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 7 January 2019). We also searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We attempted to identify randomised controlled trials, quasi-randomised controlled trials, and cluster trials comparing (1) stem cell-based interventions versus control; (2) mesenchymal stromal cells (MSCs) of type or source versus MSCs of other type or source; (3) stem cell-based interventions other than MSCs of type or source versus stem cell-based interventions other than MSCs of other type or source; or (4) MSCs versus stem cell-based interventions other than MSCs. For prevention studies, we included extremely preterm infants (less than 28 weeks' gestation), 24 hours of age or less, without ultrasound diagnosis of GM-IVH; for treatment studies, we included preterm infants (less than 37 weeks' gestation), of any postnatal age, with ultrasound diagnosis of GM-IVH.

DATA COLLECTION AND ANALYSIS

For each of the included trials, two review authors independently planned to extract data (e.g. number of participants, birth weight, gestational age, type and source of MSCs, other stem cell-based interventions) and assess the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). Primary outcomes considered in this review are all-cause neonatal mortality, major neurodevelopmental disability, GM-IVH, and extension of pre-existing non-severe GM-IVH. We planned to use the GRADE approach to assess the quality of evidence.

MAIN RESULTS

Our search strategy yielded 769 references. We did not find any completed studies for inclusion. One randomised controlled trial is currently registered and ongoing. Five phase 1 trials are described in the excluded studies.

AUTHORS' CONCLUSIONS

Currently no evidence is available to show the benefits or harms of stem cell-based interventions for treatment or prevention of GM-IVH in preterm infants.

Human umbilical cord blood monocytes, but not adult blood monocytes, rescue brain cells from hypoxic-ischemic injury: Mechanistic and therapeutic implications

Cord blood (CB) mononuclear cells (MNC) are being tested in clinical trials to treat hypoxic-ischemic (HI) brain injuries. Although early results are encouraging, mechanisms underlying potential clinical benefits are not well understood. To explore these mechanisms further, we exposed mouse brain organotypic slice cultures to oxygen and glucose deprivation (OGD) and then treated the brain slices with cells from CB or adult peripheral blood (PB). We found that CB-MNCs protect neurons from OGD-induced death and reduced both microglial and astrocyte activation. PB-MNC failed to affect either outcome. The protective activities were largely mediated by factors secreted by CB-MNC, as direct cell-to-cell contact between the injured brain slices and CB cells was not essential. To determine if a specific subpopulation of CB-MNC are responsible for these protective activities, we depleted CB-MNC of various cell types and found that only removal of CB CD14⁺ monocytes abolished neuroprotection. We also used positively selected subpopulations of CB-MNC and PB-MNC in this assay and demonstrated that purified CB-CD14⁺ cells, but not CB-PB CD14⁺ cells, efficiently protected neuronal cells from death and reduced glial activation following OGD. Gene expression microarray analysis demonstrated that compared to PB-CD14⁺ monocytes, CB-CD14⁺ monocytes over-expressed several secreted proteins with potential to protect neurons. Differential expression of five candidate effector molecules, chitinase 3-like protein-1, inhibin-A, interleukin-10, matrix metalloproteinase-9 and thrombospondin-1, were confirmed by western blotting, and immunofluorescence. These findings suggest that CD14⁺ monocytes are a critical cell-type when treating HI with CB-MNC.

Advanced nanotherapies to promote neuroregeneration in the injured newborn brain

Neonatal brain injury affects thousands of babies each year and may lead to long-term and permanent physical and neurological problems. Currently, therapeutic hypothermia is standard clinical care for term newborns with moderate to severe neonatal encephalopathy. Nevertheless, it is not completely protective, and additional strategies to restore and promote regeneration are urgently needed. One way to ensure recovery following injury to the immature brain is to augment endogenous regenerative pathways. However, novel strategies such as stem cell therapy, gene therapies and nanotechnology have not been adequately explored in this unique age group. In this perspective review, we describe current efforts that promote neuroprotection and potential targets that are unique to the developing brain, which can be leveraged to facilitate neuroregeneration.

Autologous CD34+ Cell Therapy for Ischemic Tissue Repair

In 1997, the seminal manuscript by Asahara, Murohara, Isner et al outlined the evidence for the existence of circulating, bone marrow-derived cells capable of stimulating and contributing to the formation of new blood vessels. Consistent with the paradigm shift that this work represented, it triggered much scientific debate and controversy, some of which persists 2 decades later. In contrast, the clinical application of autologous CD34 cell therapy has been marked by a track record of consistent safety and clinical benefit in multiple ischemic conditions. In this review, we summarize the preclinical and clinical evidence from over 700 patients in clinical trials of CD34 cell therapy.

Placenta-Derived Cells for Acute Brain Injury

Acute brain injury resulting from ischemic/hemorrhagic or traumatic damage is one of the leading causes of mortality and disability worldwide and is a significant burden to society. Neuroprotective options to counteract brain damage are very limited in stroke and traumatic brain injury (TBI). Given the multifaceted nature of acute brain injury and damage progression, several therapeutic targets may need to be addressed simultaneously to interfere with the evolution of the injury and improve the patient’s outcome. Stem cells are ideal candidates since they act on various mechanisms of protection and repair, improving structural and functional outcomes after experimental stroke or TBI. Stem cells isolated from placenta offer advantages due to their early embryonic origin, ease of procurement, and ethical acceptance. We analyzed the evidence for the beneficial effects of placenta-derived stem cells in acute brain injury, with the focus on experimental studies of TBI and stroke, the engineering strategies pursued to foster cell potential, and characterization of the bioactive molecules secreted by placental cells, known as their secretome, as an alternative cell-free strategy. Results from the clinical application of placenta-derived stem cells for acute brain injury and ongoing clinical trials are summarily discussed.

Effects of human umbilical cord blood CD34+ cell transplantation in neonatal hypoxic-ischemia rat model

Perinatal brain injury can cause death in the neonatal period and lifelong neurodevelopmental deficits. Stem cell transplantation had been proved to be effective approach to ameliorate neurological deficits after brain damage. In this study we examine the effect of human umbilical cord blood CD34⁺ cells on model of neonatal rat hypoxic-ischemic brain damage and compared the neuroprotection of transplantation of CD34⁺ cells to mononuclear cells from which CD34⁺ cells isolated on neonatal hypoxic-ischemia rat model. Seven-day-old Sprague-Dawley rats were subjected to hypoxic-ischemic (HI) injury, CD34⁺ cells (1.5 × 10⁴ cells) or mononuclear cells (1.0 × 10⁶ cells) were transplanted into mice by tail vein on the 7 day after HI. The transplantation of CD34⁺ cells significantly improved motor function of rat, and reduced cerebral atrophy, inhibited the expression of glial fibrillary acidic protein (GFAP) and apoptosis-related genes: TNF-α, TNFR1, TNFR2, CD40, Fas, and decreased the activation of Nuclear factor kappa B (NF-κB) in damaged brain. CD34⁺ cells treatment increased the expression of DCX and lectin in ipsilateral brain. Moreover, the transplantation of CD34⁺ cells and MNCs which were obtained from the same amount of human umbilical cord blood had similar effects on HI. Our data demonstrated that transplantation of human umbilical cord blood CD34+ cells can ameliorate the neural functional defect and reduce apoptosis and promote nerve and vascular regeneration in rat brain after HI injury and the effects of transplantation of CD34+ cells were comparable to that of MNCs in neonatal hypoxic-ischemia rat model.

Administration of Bone Marrow-Derived Mononuclear Cells Contributed to the Reduction of Hypoxic-Ischemic Brain Injury in Neonatal Rats

Background/Objective: Perinatal hypoxic-ischemia (HI) causes neonatal death and permanent neurological deficits. Cell therapy using various cell sources has been recently identified as a novel therapy for perinatal HI. Among the available types of cell sources, bone marrow-derived mononuclear cells (BMMNCs) have unique features for clinical application. For example, stem cells can be collected after admission, thus enabling us to perform autologous transplantation. This study aimed to investigate whether the administration of BMMNCs ameliorated HI brain injury in a neonatal rat model. Methods: Seven-day-old rats underwent left carotid artery ligation and were exposed to 8% oxygen for 60 min. BMMNCs were collected from the femurs and tibias of juvenile rats using the Ficoll-Hypaque technique and injected intravenously 24 h after the insult (1 × 10⁵ cells). Active caspase-3, as an apoptosis marker, and ED1, as an activated microglia/macrophage marker, were evaluated immunohistochemically 48 h after the insult (vehicle, n = 9; BMMNC, n = 10). Behavioral assessments using the rotarod treadmill, gait analysis, and active avoidance tests were initiated 3 weeks after the insult (sham, n = 9, vehicle, n = 8; BMMNC, n = 8). After these behavioral tests (6 weeks after the insult), we evaluated the volumes of their hippocampi, cortices, thalami, striata, and globus pallidus. Results: The mean cell densities of the sum of four parts that were positive for active caspase-3 significantly decreased in the BMMNC group (p < 0.05), whereas in the hippocampi, cortices, thalami, and striata cell densities decreased by 42, 60, 56, and 47%, respectively, although statistical significance was not attained. The number of ED1 positive cells for the sum of the four parts also significantly decreased in the BMMNC group compared to the vehicle group (p < 0.05), whereas in each of the four parts the decrease was 35, 39, 47, and 36%, respectively, although statistical significance was not attained. In gait analysis, the BMMNC normalized the contact area of the affected hind paw widened by HI. The volumes of the affected striata and globus pallidus were significantly larger in the BMMNC group than in the control group. Conclusion: These results indicated that the injection of BMMNCs ameliorated HI brain injury in a neonatal rat model.

A New Approach to Cerebral Palsy Treatment: Discussion of the Effective Components of Umbilical Cord Blood and its Mechanisms of Action

Cerebral palsy (CP) includes a group of persistent non-progressive disorders affecting movement, muscle tone, and/or posture. The total economic loss during the life-span of an individual with CP places a heavy financial burden on such patients and their families worldwide; however, a complete cure is still lacking. Umbilical cord blood (UCB)-based interventions are emerging as a scientifically plausible treatment and possible cure for CP. Stem cells have been used in many experimental CP animal models and achieved good results. Compared with other types of stem cells, those from UCB have advantages in terms of treatment safety and efficacy, ethics, non-neoplastic proliferation, accessibility, ease of preservation, and regulation of immune responses, based on findings in animal models and clinical trials. Currently, the use of UCB-based interventions for CP is limited as the components of UCB are complex and possess different therapeutic mechanisms. These can be categorized by three aspects: homing and neuroregeneration, trophic factor secretion, and neuroprotective effects. Our review summarizes the features of active components of UCB and their therapeutic mechanism of action. This review highlights current research findings and clinical evidence regarding UCB that contribute to treatment suggestions, inform decision-making for therapeutic interventions, and help to direct future research.

Intravenous Administration of Bone Marrow-Derived Mesenchymal Stem Cell, but not Adipose Tissue-Derived Stem Cell, Ameliorated the Neonatal Hypoxic-Ischemic Brain Injury by Changing Cerebral Inflammatory State in Rat

Perinatal hypoxic-ischemic (HI) brain injury occurs in 1 in 1,000 live births and remains the main cause of neurological disability and death in term infants. Cytotherapy has recently emerged as a novel treatment for tissue injury. In particular, mesenchymal stem cells (MSCs) are thought to have therapeutic potential, but little is known about the differences according to their origin. In the current study, we investigated the therapeutic effects and safety of intravenous injection of allogeneic bone marrow-derived MSCs (BM-MSCs) and adipose-derived stem cells (ADSCs) in a rat model of HI brain injury. HI models were generated by ligating the left carotid artery of postnatal day 7 Wistar/ST rats and exposing them to 8% hypoxia for 60 min. Bone marrow and adipose tissue were harvested from adult green fluorescent protein transgenic Wistar rats, and cells were isolated and cultured to develop BM-MSCs and ADSCs. At passaging stages 2–3, 1 × 10⁵ cells were intravenously injected into the external right jugular vein of the HI rats at 4 or 24 h after hypoxia. Brain damage was evaluated by counting the number of cells positive for active caspase-3 in the entire dentate gyrus. Microglial isotypes and serum cytokines/chemokines were also evaluated. Distribution of each cell type after intravenous injection was investigated pathologically and bio-optically by ex vivo imaging (IVIS®) with a fluorescent lipophilic tracer DiR. The mortality rate was higher in the ADSC group compared to the BM-MSC group, in pups injected with cells 4 h after hypoxia. The number of active caspase-3-positive cells significantly decreased in the BM-MSC group, and the percentage of M1 microglia (a proinflammatory isotype) was also lower in the BM-MSC vs control group in the penumbra of the cortex. Moreover, BM-MSC administration increased anti-inflammatory cytokine and growth factor levels, while ADSCs did not. Each injected cell type was mainly distributed in the lungs and liver, but ADSCs remained in the lungs longer. Pathologically, pulmonary embolisms and diffuse alveolar hemorrhages were seen in the ADSC group. These results indicated that injection of allogeneic BM-MSCs ameliorated neonatal HI brain injury, whereas ADSCs induced severe lung hemorrhage and higher mortality.

Dose-Dependent Effect of Intravenous Administration of Human Umbilical Cord-Derived Mesenchymal Stem Cells in Neonatal Stroke Mice

Neonatal brain injury induced by stroke causes significant disability, including cerebral palsy, and there is no effective therapy for stroke. Recently, mesenchymal stem cells (MSCs) have emerged as a promising tool for stem cell-based therapies. In this study, we examined the safety and efficacy of intravenously administered human umbilical cord-derived MSCs (UC-MSCs) in neonatal stroke mice. Pups underwent permanent middle cerebral artery occlusion at postnatal day 12 (P12), and low-dose (1 × 10⁴) or high-dose (1 × 10⁵) UC-MSCs were administered intravenously 48 h after the insult (P14). To evaluate the effect of the UC-MSC treatment, neurological behavior and cerebral blood flow were measured, and neuroanatomical analysis was performed at P28. To investigate the mechanisms of intravenously injected UC-MSCs, systemic blood flowmetry, in vivo imaging and human brain-derived neurotrophic factor (BDNF) measurements were performed. Functional disability was significantly improved in the high-dose UC-MSC group when compared with the vehicle group, but cerebral blood flow and cerebral hemispheric volume were not restored by UC-MSC therapy. The level of exogenous human BDNF was elevated only in the cerebrospinal fluid of one pup 24 h after UC-MSC injection, and in vivo imaging revealed that most UC-MSCs were trapped in the lungs and disappeared in a week without migration toward the brain or other organs. We found that systemic blood flow was stable over the 10 min after cell administration and that there were no differences in mortality among the groups. Immunohistopathological assessment showed that the percent area of Iba1-positive staining in the peri-infarct cortex was significantly reduced with the high-dose UC-MSC treatment compared with the vehicle treatment. These results suggest that intravenous administration of UC-MSCs is safe for a mouse model of neonatal stroke and improves dysfunction after middle cerebral artery occlusion by modulating the microglial reaction in the peri-infarct cortex.

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.

Future perspectives of cell therapy for neonatal hypoxic-ischemic encephalopathy

Neonatal ischemic brain injury causes permanent motor-deficit cerebral palsy. Hypoxic-ischemic encephalopathy (HIE) is a very serious condition that can result in death and disability. In 1997, we reported that irreversible neuronal cell damage is induced by the elevation of intracellular Ca ion concentration that has occurred in sequence after excess accumulation of the excitatory neurotransmitter glutamate during ischemia. We also reported that hypothermia was effective in treating ischemic brain damage in rats by suppressing energy loss and raising intracellular Ca ion concentration. Following the 2010 revised International Liaison Committee on Resuscitation guideline, our group developed the Guideline for the treatment of Hypothermia in Japan, and we started online case registry in January 2012. However, therapeutic hypothermia must be initiated within the first 6 h after birth. By contrast, cell therapy may have a much longer therapeutic time window because it might reduce apoptosis/oxidative stress and enhance the regenerative process. In 2014, we administered autologous umbilical cord blood stem cell (UCBC) therapy for neonatal HIE, for the first time in Japan. We enrolled five full-term newborns with moderate-to-severe HIE. Our autologous UCBC therapy is leading to new protocols for the prevention of ischemic brain damage.

Term vs. preterm cord blood cells for the prevention of preterm brain injury

BACKGROUNDWhite matter brain injury in preterm infants can induce neurodevelopmental deficits. Umbilical cord blood (UCB) cells demonstrate neuroprotective properties, but it is unknown whether cells obtained from preterm cord blood (PCB) vs. term cord blood (TCB) have similar efficacy. This study compared the ability of TCB vs. PCB cells to reduce white matter injury in preterm fetal sheep.METHODSHypoxia-ischemia (HI) was induced in fetal sheep (0.7 gestation) by 25 min umbilical cord occlusion. Allogeneic UCB cells from term or preterm sheep, or saline, were administered to the fetus at 12 h after HI. The fetal brain was collected at 10-day post HI for assessment of white matter neuropathology.RESULTSHI (n=7) induced cell death and microglial activation and reduced total oligodendrocytes and CNPase+myelin protein in the periventricular white matter and internal capsule when compared with control (n=10). Administration of TCB or PCB cells normalized white matter density and reduced cell death and microgliosis (P<0.05). PCB prevented upregulation of plasma tumor necrosis factor (TNF)-a, whereas TCB increased anti-inflammatory interleukin (IL)-10 (P<0.05). TCB, but not PCB, reduced circulating oxidative stress.CONCLUSIONSTCB and PCB cells reduced preterm HI-induced white matter injury, primarily via anti-inflammatory actions. The secondary mechanisms of neuroprotection appear different following TCB vs. PCB administration.

Phase I/II randomized controlled trial of autologous bone marrow-derived mesenchymal stem cell therapy for chronic stroke

AIM

To examine the safety and efficacy of mesenchymal stem cell (MSC) therapy for intracerebral haemorrhage with neurological dysfunctions for a year.

METHODS

MSC were ex vivo expanded from 29 mL (17-42 mL) autologous bone marrow. Patients were randomized to have two intravenous injections of autologous MSC or placebos in four weeks apart. Neurological functions and clinical outcomes were monitored before treatment and at 12^th, 16^th, 24^th, 36^th and 60^th week upon completion of the treatment.

RESULTS

A mean of 4.57 × 10⁷ (range: 1.43 × 10⁷-8.40 × 10⁷) MSC per infusion was administered accounting to 8.54 × 10⁵ (2.65 × 10⁵-1.45 × 10⁶) per kilogram body weight in two occasions. There was neither adverse event at time of administration nor sign of de novo tumour development among patients after monitoring for a year post MSC therapy. Neuro-restoration and clinical improvement in terms of modified Barthel index, functional independence measure and extended Glasgow Outcome Scale were evident among patients having MSC therapy compared to patients receiving placebos.

CONCLUSION

Intravenous administration of autologous bone marrow-derived MSC is safe and has the potential of improving neurological functions in chronic stroke patients with severe disability.

Endothelial Progenitor Cells' Classification and Application in Neurological Diseases

The therapeutic effects of endothelial progenitor cells (EPCs) on ischemic stroke have been extensively studied in recent years. However, the differences in early EPCs and endothelial outgrowth cells (EOCs) are still unclear. Clarifications of their respective properties and specific functioning characteristics contribute to better applications of EPCs in ischemic diseases. In this review, we discuss cellular origin, isolation, culture, surface markers of early EPCs and EOCs and relevant applications in neurological diseases. We conclude that EOCs possess all characteristics of true endothelial progenitors and have potent advantages in EPC-based therapies for ischemic diseases. A number of preclinical and clinical applications of EPCs in neurological diseases are under study. More studies are needed to determine the specific characteristics of EPCs and the relevant mechanisms of EPCs for neurological diseases.

Rat umbilical cord blood cells attenuate hypoxic-ischemic brain injury in neonatal rats

Increasing evidence has suggested that human umbilical cord blood cells (hUCBC) have a favorable effect on hypoxic-ischemic (HI) brain injury. However, the efficacy of using hUCBCs to treat this injury has been variable and the underlying mechanism remains elusive. Here, we investigated its effectiveness using stereological analysis in an allogeneic system to examine whether intraperitoneal injection of cells derived from UCBCs of green fluorescent protein (GFP)-transgenic rats could ameliorate brain injury in neonatal rats. Three weeks after the HI event, the estimated residual brain volume was larger and motor function improved more in the cell-injected rats than in the control (PBS-treated) rats. The GFP-positive cells were hardly detectable in the brain (0.0057% of injected cells) 9 days after injection. Although 60% of GFP-positive cells in the brain were Iba1-positive, none of these were positive for NeuroD or DCX. While the number of proliferating cells increased in the hippocampus, that of activated microglia/macrophages decreased and a proportion of M2 microglia/macrophages increased in the ipsilateral hemisphere of cell-injected rats. These results suggest that intraperitoneal injection of cells derived from UCBCs could ameliorate HI injury, possibly through an endogenous response and not by supplying differentiated neurons derived from the injected stem cells.

Human Umbilical Cord Blood CD34-Positive Cells as Predictors of the Incidence and Short-Term Outcome of Neonatal Hypoxic-Ischemic Encephalopathy: A Pilot Study

BACKGROUND AND PURPOSE

Neonatal hypoxic-ischemic encephalopathy (HIE) is one of the leading causes of neurological handicap in developing countries. Human umbilical cord blood (hUCB) CD34-positive (CD34⁺) stem cells exhibit the potential for neural repair. We tested the hypothesis that hUCB CD34⁺ stem cells and other cell types [leukocytes and nucleated red blood cells (NRBCs)] that are up-regulated during the acute stage of perinatal asphyxia (PA) could play a role in the early prediction of the occurrence, severity, and mortality of HIE.

METHODS

This case-control pilot study investigated consecutive neonates exposed to PA. The hUCB CD34⁺ cell count in mononuclear layers was assayed using a flow cytometer. Twenty full-term neonates with PA and 25 healthy neonates were enrolled in the study.

RESULTS

The absolute CD34⁺ cell count (p=0.02) and the relative CD34⁺ cell count (CD34⁺%) (p<0.001) in hUCB were higher in the HIE patients (n=20) than the healthy controls. The hUCB absolute CD34⁺ cell count (p=0.04), CD34⁺% (p<0.01), and Hobel risk scores (p=0.04) were higher in patients with moderate-to-severe HIE (n=9) than in those with mild HIE (n=11). The absolute CD34⁺ cell count was strongly correlated with CD34⁺% (p<0.001), Hobel risk score (p=0.04), total leukocyte count (TLC) (p<0.001), and NRBC count (p=0.01). CD34⁺% was correlated with TLC (p=0.02).

CONCLUSIONS

hUCB CD34⁺ cells can be used to predict the occurrence, severity, and mortality of neonatal HIE after PA.

Quality and exploitation of umbilical cord blood for cell therapy: Are we beyond our capabilities?

There is increasing interest in identifying novel stem cell sources for application in emerging cell therapies. In this context, umbilical cord blood (UCB) shows great promise in multiple clinical settings. The number of UCB banks has therefore increased worldwide, with the objective of preserving potentially life-saving cells that are usually discarded after birth. After a rather long and costly processing procedure, the resultant UCB-derived cell products are cryopreserved until transplantation to patients. However, in many cases, only a small proportion of administered cells engraft successfully. Thus, can we do any better regarding current UCB-based therapeutic approaches? Here we discuss concerns about the use of UCB that are not critically pondered by researchers, clinicians, and banking services, including wasting samples with small volumes and the need for more reliable quality and functional controls to ensure the biological activity of stem cells and subsequent engraftment and treatment efficacy. Finally, we appeal for collaborative agreements between research institutions and UCB banks in order to redirect currently discarded small-volume UCB units for basic and clinical research purposes. Developmental Dynamics 245:710-717, 2016. © 2016 Wiley Periodicals, Inc.

Systemic human CD34(+) cells populate the brain and activate host mechanisms to counteract nigrostriatal degeneration

AIM

Here we investigated the neuroprotective potential of systemic CD34(+) human cord blood cells (hCBCs) in a 6-hydroxydopamine rat model of Parkinson's disease.

METHODS

Purified CD34(+) hCBCs were intravenously administered to rats subjected to 6-hydroxydopamine 24 h earlier, and behavioral and immunohistological analysis performed.

RESULTS

CD34(+) hCBC administration significantly prevented host nigrostriatal degeneration inducing behavioral recovery in treated rats. Although donor hCBCs did not differentiate into neural phenotypes, they stimulated the production of new neuroblasts and angiogenesis, and reduced gliosis in recipient animals. Importantly, surviving donor hCBCs were identified, and their tissue distribution pattern correlated with the observed therapeutic effects.

CONCLUSION

Peripherally applied CD34(+) hCBCs can migrate into brain tissues and elicit host-based protective mechanisms to support the survival of midbrain dopamine neurons.

ESAM is a novel human hematopoietic stem cell marker associated with a subset of human leukemias

Reliable markers are essential to increase our understanding of the biological features of human hematopoietic stem cells and to facilitate the application of hematopoietic stem cells in the field of transplantation and regenerative medicine. We previously identified endothelial cell-selective adhesion molecule (ESAM) as a novel functional marker of hematopoietic stem cells in mice. Here, we found that ESAM can also be used to purify human hematopoietic stem cells from all the currently available sources (adult bone marrow, mobilized peripheral blood, and cord blood). Multipotent colony-forming units and long-term hematopoietic-reconstituting cells in immunodeficient mice were found exclusively in the ESAM(High) fraction of CD34(+)CD38(-) cells. The CD34(+)CD38(-) fraction of cord blood and collagenase-treated bone marrow contained cells exhibiting extremely high expression of ESAM; these cells are likely to be related to the endothelial lineage. Leukemia cell lines of erythroid and megakaryocyte origin, but not those of myeloid or lymphoid descent, were ESAM positive. However, high ESAM expression was observed in some primary acute myeloid leukemia cells. Furthermore, KG-1a myeloid leukemia cells switched from ESAM negative to ESAM positive with repeated leukemia reconstitution in vivo. Thus, ESAM is a useful marker for studying both human hematopoietic stem cells and leukemia cells.