Changes in Interleukin-1 alpha serum levels after transplantation of umbilical cord blood cells in a model of perinatal hypoxic-ischemic brain damage

Mononuclear cell therapy of neonatal hypoxic-ischemic encephalopathy in preclinical versus clinical studies: a systematic analysis of therapeutic efficacy and study design

Background

Hypoxic-ischemic encephalopathy (HIE) is a devastating condition affecting around 8.5 in 1000 newborns globally. Therapeutic hypothermia (TH) can reduce mortality and, to a limited extent, disability after HIE. Nevertheless, there is a need for new and effective treatment strategies. Cell based treatments using mononuclear cells (MNC), which can be sourced from umbilical cord blood, are currently being investigated. Despite promising preclinical results, there is currently no strong indicator for clinical efficacy of the approach. This analysis aimed to provide potential explanations for this discrepancy.

Methods

A systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. Preclinical and clinical studies were retrieved from PubMed, Web of Science, Scopus, and clinicaltrials.gov using a predefined search strategy. A total of 17 preclinical and 7 clinical studies were included. We analyzed overall MNC efficacy in preclinical trials, the methodological quality of preclinical trials and relevant design features in preclinical versus clinical trials.

Results

There was evidence for MNC therapeutic efficacy in preclinical models of HIE. The methodological quality of preclinical studies was not optimal, and statistical design quality was particularly poor. However, methodological quality was above the standard in other fields. There were significant differences in preclinical versus clinical study design including the use of TH as a baseline treatment (only in clinical studies) and much higher MNC doses being applied in preclinical studies.

Conclusions

Based on the analyzed data, it is unlikely that therapeutic effect size is massively overestimated in preclinical studies. It is more plausible that the many design differences between preclinical and clinical trials are responsible for the so far lacking proof of efficacy of MNC treatments in HIE. Additional preclinical and clinical research is required to optimize the application of MNC for experimental HIE treatment.

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.

Umbilical Cord Blood Mononuclear Cell Treatment for Neonatal Rats With Hypoxic Ischemia

Background

Hypoxic-ischemic encephalopathy (HIE) occurs when an infant’s brain has not received adequate oxygen and blood supply, resulting in ischemic and hypoxic damage. Currently, supportive care and hypothermia therapy have been the standard treatment for HIE. However, there are still over 20% of treated infants died and 19–30% survived with significant disability. HIE animal model was first established by Rice et al., involving the ligation of one common carotid artery followed by hypoxia. In this study, we investigated human umbilical cord blood (HUCB) and its two components mononuclear cell (MNC) and red cell fraction (RCF) in both short and long term study using a modified HIE rat model.

Methods

In this modified HIE model, both common carotid arteries were occluded, breathing 8% oxygen in a hypoxic chamber for 60-min, followed by the release of the common carotid arteries ligature, mimicking reperfusion injury. For cell therapeutic study, cells were intravenously injected to HIE rat pups, and both behavioral and histological changes were assessed at selected time points.

Result

Statistically significant behavioral improvements were demonstrated on Day 7 and 1 month between saline treated HIE rats and UCB/MNC treated rats. However, at 3 months, the therapeutic improvements were only showed between saline treated HIE animals and MNC treated HIE rats. For histological analysis 1 month after cell injection, the number of functional neurons were statistically increased between saline treated HIE and UCB/MNC/RCF treated HIE rats. At 3 months, the significant increase in functional neurons was only present in MNC treated HIE rats.

Conclusion

We have used a bilateral temporary occlusion of 60 min, a moderately brain damaged model, for cell therapeutic studies. HUCB mononuclear cell (MNC) therapy showed benefits in neonatal HIE rats in both short and long term behavioral and histological assessments.

Complete Restoration of Motor Function in Acute Cerebral Stroke Treated with Allogeneic Human Umbilical Cord Blood Monocytes: Preliminary Results of a phase I Clinical Trial

Stem cell therapy has been explored for the treatment of cerebral stroke. Several types of stem cells have been investigated to ensure the safety and efficacy in clinical trials.Cryopreserved umbilical cord blood (UCB) mononuclear cells (MNCs) obtained from healthy donors have a more stabilized quality, thereby ensuring a successful therapy. A phase I study was conducted on patients aged 45-80 years who sustained acute ischemic stroke. An UCB unit was obtained from a public cord blood bank based on ABO/Rh blood type, HLA matching score (6/6), and cell dose (total MNC count of 0.5-5 × 10⁷ cells/kg). In addition, to facilitate blood brain barrier penetration of UCB, 4 doses of 100 mL mannitol was administered intravenously after 30 min after UCB transplantation and every 4 h thereafter. The primary outcomes were the number of disease (GVHD) within 100 days after transfusion. The secondary outcomes were changes in the National Institutes of Health Stroke Scale (NIHSS), Barthel index, and Berg Balance Scale scores. A 46-year-old male patient with identical ABO/Rh blood type, HLA matching score of 6/6, and MNC count of 2.63 × 10⁸ cells/kg was enrolled. The patient did not present with serious AEs or GVHD during the 12-month study period. The patient's NIHSS score decreased from 9 to 1. Moreover, the Berg Balance Scale score increased from 0 to 48 and the Barthel index score from 0 to 90. This preliminary study showed that an adult patient with hemiplegia due to ischemic stroke completely recovered within 12 months after receiving allogeneic UCB therapy.

Stem Cell Therapy for Neonatal Hypoxic-Ischemic Encephalopathy: A Systematic Review of Preclinical Studies

Neonatal hypoxic-ischemic encephalopathy (HIE) is an important cause of mortality and morbidity in the perinatal period. This condition results from a period of ischemia and hypoxia to the brain of neonates, leading to several disorders that profoundly affect the daily life of patients and their families. Currently, therapeutic hypothermia (TH) is the standard of care in developing countries; however, TH is not always effective, especially in severe cases of HIE. Addressing this concern, several preclinical studies assessed the potential of stem cell therapy (SCT) for HIE. With this systematic review, we gathered information included in 58 preclinical studies from the last decade, focusing on the ones using stem cells isolated from the umbilical cord blood, umbilical cord tissue, placenta, and bone marrow. Outstandingly, about 80% of these studies reported a significant improvement of cognitive and/or sensorimotor function, as well as decreased brain damage. These results show the potential of SCT for HIE and the possibility of this therapy, in combination with TH, becoming the next therapeutic approach for HIE. Nonetheless, few preclinical studies assessed the combination of TH and SCT for HIE, and the existent studies show some contradictory results, revealing the need to further explore this line of research.

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.

A Randomized, Placebo-Controlled Trial of Human Umbilical Cord Blood Mesenchymal Stem Cell Infusion for Children With Cerebral Palsy

Cerebral palsy (CP) is a common disability which results in permanent chronic motor disability appearing in early childhood. Recently human umbilical cord blood mesenchymal stem cell (hUCB-MSC) infusion has emerged as a promising therapeutic strategy for CP, and the treatment efficacy remains to be confirmed by clinical trials. All 54 patients received basic rehabilitation as a background treatment. The infusion group comprising 27 patients received 4 infusions of hUCB-MSCs (intravenous infusions at a fixed dose of 5 × 10⁷) and basic rehabilitation treatment, whereas 27 patients in the control group received 0.9% normal saline and basic rehabilitation treatment. Several indices were tested from baseline up to 24 months posttreatment regarding efficacy and safety evaluations, including the gross motor function measurement 88 (GMFM-88) scores, the comprehensive function assessment (CFA), lab tests, electroencephalogram (EEG), routine magnetic resonance imaging (MRI), and adverse events. The changes in the total proportion of GMFM-88 and total scores of CFA in the hUCB-MSC infusion group were significantly higher than that in control group at 3, 6, 12, 24 months posttreatment. Less diffuse slow waves were noticed after hUCB-MSC infusion in patients with slowing of EEG background rhythms at baseline. Based on the routine MRI exams, improvements in cerebral structures were rare after treatment. Serious adverse events were not observed during the whole study period. The results of the study indicated that hUCB-MSC infusion with basic rehabilitation was safe and effective in improving gross motor and comprehensive functions in children with CP.

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.

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.

Immune responses in perinatal brain injury

The perinatal period has often been described as immune deficient. However, it has become clear that immune responses in the neonate following exposure to microbes or as a result of tissue injury may be substantial and play a role in perinatal brain injury. In this article we will review the immune cell composition under normal physiological conditions in the perinatal period, both in the human and rodent. We will summarize evidence of the inflammatory responses to stimuli and discuss how neonatal immune activation, both in the central nervous system and in the periphery, may contribute to perinatal hypoxic-ischemic brain injury.

Interleukin-1α and brain inflammation

Acute brain injuries such as caused by stroke are amongst the leading causes of death and are the leading cause of disability. Despite this there are very limited therapeutic options, and new therapeutic strategies and targets are required. Inflammation is known to exacerbate brain injury and is now considered as a potential therapeutic target. The damaging inflammation that occurs after acute brain injury is driven by pro-inflammatory members of the interleukin (IL)-1 cytokine family, namely, IL-1α and IL-1β. Previous research efforts have focussed on the biology and contribution of IL-1β. However, we now recognise that IL-1α is an early and important mediator of inflammation after injury. This review focuses on what is known about IL-1α, its regulation and its contribution to brain injury. Inhibiting mechanisms regulating the processing and release of IL-1α may offer new therapeutic targets for the treatment of devastating acute brain injuries.

Intraperitoneal and intravenous deliveries are not comparable in terms of drug efficacy and cell distribution in neonatal mice with hypoxia-ischemia

BACKGROUND AND PURPOSE

Most therapeutic agents are administered intravenously (IV) in clinical settings and intraperitoneally (IP) in preclinical studies with neonatal rodents; however, it remains unclear whether intraperitoneal (IP) injection is truly an acceptable alternative for intravenous (IV) injection in preclinical studies. The objective of our study is to clarify the differences in the therapeutic effects of drugs and in the distribution of infused cells after an IP or IV injection in animals with brain injury.

METHODS

Dexamethasone or MK-801, an N-methyl-d-aspartate receptor antagonist was administered either IP or IV in a mouse model of neonatal hypoxic-ischemic encephalopathy. Green fluorescent protein-expressing mesenchymal stem cells (MSCs) or mononuclear cells (MNCs) were injected IP or IV in the mouse model. Two hours and 24h after the administration of the cells, we investigated the cell distributions by immunohistochemical staining. We also investigated distribution of IV administered MNCs labeled with 2-[18F]fluoro-2-deoxy-d-glucose in a juvenile primate, a macaque with stroke 1h after the administration.

RESULTS

IP and IV administration of dexamethasone attenuated the brain injury to a similar degree. IP administration of MK-801 attenuated brain injury, whereas IV administration of MK-801 did not. The IV group showed a significantly greater number of infused cells in the lungs and brains in the MSC cohort and in the spleen, liver, and lung in the MNC cohort compared to the IP group. In the macaque, MNCs were detected in the spleen and liver in large amounts, but not in the brain and lungs.

CONCLUSIONS

This study demonstrated that the administration route influences the effects of drugs and cell distribution. Therefore, a preclinical study may need to be performed using the optimal administration route used in a clinical setting.

Administration of umbilical cord blood cells transiently decreased hypoxic-ischemic brain injury in neonatal rats

This study aimed to investigate whether the administration of mononuclear cells derived from human umbilical cord blood cells (UCBCs) could ameliorate hypoxic-ischemic brain injury in a neonatal rat model. The left carotid arteries of 7-day-old rats were ligated, and the rats were then exposed to 8% oxygen for 60 min. Mononuclear cells derived from UCBCs using the Ficoll-Hypaque technique were injected intraperitoneally 6 h after the insult (1.0 × 10(7) cells). Twenty-four hours after the insult, the number of cells positive for the oxidative stress markers 4-hydroxy-2-nonenal and nitrotyrosine, in the dentate gyrus of the hippocampus in the UCBC-treated group, decreased by 36 and 42%, respectively, compared with those in the control group. In addition, the number of cells positive for the apoptosis markers active caspase-3 and apoptosis-inducing factor decreased by 53 and 58%, respectively. The number of activated microglia (ED1-positive cells) was 51% lower in the UCBC group compared with the control group. In a gait analysis performed 2 weeks after the insult, there were no significant differences among the sham-operated, control and UCBC groups. An active avoidance test using a shuttle box the following week also revealed no significant differences among the groups. Neither the volumes of the hippocampi, corpus callosum and cortices nor the numbers of neurons in the hippocampus were different between the UCBC and control groups. In summary, a single intraperitoneal injection of UCBC-derived mononuclear cells 6 h after an ischemic insult was associated with a transient reduction in numbers of apoptosis and oxidative stress marker-positive cells, but it did not induce long-term morphological or functional protection. Repeated administration or a combination treatment may be required to achieve sustained protection.

Current proceedings of cerebral palsy

Cerebral palsy (CP) is a complicated disease with varying causes and outcomes. It has created significant burden to both affected families and societies, not to mention the quality of life of the patients themselves. There is no cure for the disease; therefore, development of effective therapeutic strategies is in great demand. Recent advances in regenerative medicine suggest that the transplantation of stem cells, including embryonic stem cells, neural stem cells, bone marrow mesenchymal stem cells, induced pluripotent stem cells, umbilical cord blood cells, and human embryonic germ cells, focusing on the root of the problem, may provide the possibility of developing a complete cure in treating CP. However, safety is the first factor to be considered because some stem cells may cause tumorigenesis. Additionally, more preclinical and clinical studies are needed to determine the type of cells, route of delivery, cell dose, timing of transplantation, and combinatorial strategies to achieve an optimal outcome.

Cx43 expression and function in the nervous system-implications for stem cell mediated regeneration

Pathological conditions of the brain such as ischemia cause major sensorimotor and cognitive impairments. In novel therapeutic approaches to brain injury, stem cells have been applied to ameliorate the pathological outcome. In several experimental models, including hypoxia-ischemia and trauma, transplantation of stem cells correlated with an improved functional and structural outcome. At the cellular level, brain insults also change gap junction physiology and expression, leading to altered intercellular communication. Differences in expression in response to brain injury have been detected in particular in Cx43, the major astrocytic gap junction protein, and its overexpression or deletion was associated with the pathophysiological outcome. We here focus on Cx43 changes in host tissue mediated by stem cells. Stem cell-induced changes in connexin expression, and consecutively in gap junction channel or hemichannel function, might play a part in altered cell interaction, intercellular communication, and neural cell survival, and thereby contribute to the beneficial effects of transplanted stem cells.

Effects of intravenous administration of umbilical cord blood CD34(+) cells in a mouse model of neonatal stroke

Neonatal stroke occurs in approximately 1/4000 live births and results in life-long neurological impairments: e.g., cerebral palsy. Currently, there is no evidence-based specific treatment for neonates with stroke. Several studies have reported the benefits of umbilical cord blood (UCB) cell treatment in rodent models of neonatal brain injury. However, all of the studies examined the effects of administering either the UCB mononuclear cell fraction or UCB-derived mesenchymal stem cells in neonatal rat models. The objective of this study was to examine the effects of human UCB CD34(+) cells (hematopoietic stem cell/endothelial progenitor cells) in a mouse model of neonatal stroke, which we recently developed. On postnatal day 12, immunocompromized (SCID) mice underwent permanent occlusion of the left middle cerebral artery (MCAO). Forty-eight hours after MCAO, human UCB CD34(+) cells (1×10(5)cells) were injected intravenously into the mice. The area in which cerebral blood flow (CBF) was maintained was temporarily larger in the cell-treated group than in the phosphate-buffered saline (PBS)-treated group at 24h after treatment. With cell treatment, the percent loss of ipsilateral hemispheric volume was significantly ameliorated (21.5±1.9%) compared with the PBS group (25.6±5.1%) when assessed at 7weeks after MCAO. The cell-treated group did not exhibit significant differences from the PBS group in either rotarod (238±46s in the sham-surgery group, 175±49s in the PBS group, 203±54s in the cell-treated group) or open-field tests. The intravenous administration of human UCB CD34(+) cells modestly reduced histological ischemic brain damage after neonatal stroke in mice, with a transient augmentation of CBF in the peri-infarct area.

Mesenchymal stem cells and their subpopulation, pluripotent muse cells, in basic research and regenerative medicine

Mesenchymal stem cells (MSCs) have gained a great deal of attention for regenerative medicine because they can be obtained from easy accessible mesenchymal tissues, such as bone marrow, adipose tissue, and the umbilical cord, and have trophic and immunosuppressive effects to protect tissues. The most outstanding property of MSCs is their potential for differentiation into cells of all three germ layers. MSCs belong to the mesodermal lineage, but they are known to cross boundaries from mesodermal to ectodermal and endodermal lineages, and differentiate into a variety of cell types both in vitro and in vivo. Such behavior is exceptional for tissue stem cells. As observed with hematopoietic and neural stem cells, tissue stem cells usually generate cells that belong to the tissue in which they reside, and do not show triploblastic differentiation. However, the scientific basis for the broad multipotent differentiation of MSCs still remains an enigma. This review summarizes the properties of MSCs from representative mesenchymal tissues, including bone marrow, adipose tissue, and the umbilical cord, to demonstrate their similarities and differences. Finally, we introduce a novel type of pluripotent stem cell, multilineage-differentiating stress-enduring (Muse) cells, a small subpopulation of MSCs, which can explain the broad spectrum of differentiation ability in MSCs.