Stem cell therapy for neonatal brain injury

Safety and Efficacy of Mesenchymal Stem Cells for the Treatment of Evolving and Established Bronchopulmonary Dysplasia: A Systematic Literature Review

Bronchopulmonary dysplasia (BPD) is a frequent sequela of modern medicine when infants are born prematurely. Currently, there is no single treatment or combination of treatments to prevent or fully treat BPD. Mesenchymal stem cells (MSCs) have promising properties that could aid in the reversal of lung injury, as seen in patients with BPD. This study reviews the available evidence regarding the safety and efficacy of the use of MSCs for the treatment of evolving and established BPD. This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We found eight studies that fulfilled the inclusion and exclusion criteria. While all studies proved the safety and efficacy of MSCs administered intravenously and intratracheally, the only available randomized controlled trial (RCT) failed to demonstrate the benefit of MSC administration in the early treatment of BPD. The remaining studies varied between phase I clinical trials and case reports, but all seemed to show some evidence that MSCs may be of benefit in the late treatment of established BPD. Considering some of the studies have less evidence, early treatment to prevent lung fibrosis may be more successful, particularly in the younger gestational ages where lung development is more immature, and research should focus on this.

Emerging therapies for brain recovery after IVH in neonates: Cord blood derived Mesenchymal Stem Cells (MSC) and Unrestricted Somatic Stem Cells (USSC)

In this report, we summarize evidence on mechanisms of injury after intraventricular hemorrhage resulting in post-hemorrhagic white matter injury and hydrocephalus and correlate that with the possibility of cellular therapy. We describe how two stem cell lines (MSC & USSC) acting in a paracrine fashion offer promise for attenuating the magnitude of injury in animal models and for improved functional recovery by: lowering the magnitude of apoptosis and neuronal cell death, reducing inflammation, and thus, mitigating white matter injury that culminates in improved motor and neurocognitive outcomes. Animal models of IVH are analyzed for their similarity to the human condition and we discuss merits of each approach. Studies on stem cell therapy for IVH in human neonates is described. Lastly, we offer suggestions on what future studies are needed to better understand mechanisms of injury and recovery and argue that human trials need to be expanded in parallel to animal research.

Lack of Neuroprotection with a Single Intravenous Infusion of Human Amnion Epithelial Cells after Severe Hypoxia–Ischemia in Near-Term Fetal Sheep

Background: Hypoxic–ischemic encephalopathy (HIE) around the time of birth results from loss of oxygen (hypoxia) and blood supply (ischemia). Exogenous infusion of multi-potential cells, including human amnion epithelial cells (hAECs), can reduce hypoxic–ischemic (HI) brain injury. However, there are few data on treatment of severe HI in large animal paradigms at term. The aim of the current study was to determine whether infusion of hAECs early after injury may reduce brain damage after ischemia in near-term fetal sheep. Methods: Chronically instrumented fetal sheep (0.85 gestation) received 30 min of global cerebral ischemia followed by intravenous infusion of hAECs from 2 h after the end of ischemia (ischemia-hAEC, n = 6) or saline (ischemia-vehicle, n = 7). Sham control animals received sham ischemia with vehicle infusion (sham control, n = 8). Results: Ischemia was associated with significant suppression of EEG power and spectral edge frequency until the end of the experiment and a secondary rise in cortical impedance from 24 to 72 h, which were not attenuated by hAEC administration. Ischemia was associated with loss of neurons in the cortex, thalamus, striatum and hippocampus, loss of white matter oligodendrocytes and increased microglial numbers in the white matter, which were not affected by hAEC infusion. Conclusions: A single intravenous administration of hAECs did not reduce electrographic or histological brain damage after 30 min of global cerebral ischemia in near-term fetal sheep.

Hypoxic Ischemic Encephalopathy (HIE) in Term and Preterm Infants

Hypoxic-ischemic syndrome (HIS) and Hypoxic-ischemic encephalopathy (HIE) are conditions that affect term and premature babies, with different pathophysiology and different brain disorders. HIE appears in 1-6 / 1000 live births and 26/1000 live births in developing countries. 15-20% die in the early neonatal period, while surviving babies have severe neurological impairment, including cerebral palsy, epilepsy, visual and hearing impairment, cognitive impairment, intellectual, behavioural, and social disorders. The hypoxic-ischemic event occurs before, during or after birth. The reasons may be related to the mother, the way of birth, the placenta, and the newborn. The criteria for diagnosis of HIE include a combination of perinatal factors, the need for resuscitation, standard neurological examinations, neurophysiological monitoring, neuroimaging methods and biochemical markers. The most effective treatment for HIE is hypothermia in combination with pharmacological therapy. HIE and HIS are problem that still persist in developing countries due to inadequate obstetric care, neonatal resuscitation, and hypothermia. Current and emerging research for HIE examines new markers for early recognition, treatment, and appropriate neuroprotection of high-risk term and premature infants.

Neural stem cell treatment for perinatal brain injury: A systematic review and meta-analysis of preclinical studies

Perinatal brain injury can lead to significant neurological and cognitive deficits and currently no therapies can regenerate the damaged brain. Neural stem cells (NSCs) have the potential to engraft and regenerate damaged brain tissue. The aim of this systematic review was to evaluate the preclinical literature to determine whether NSC administration is more effective than controls in decreasing perinatal brain injury. Controlled interventional studies of NSC therapy using animal models of perinatal brain injury were identified using MEDLINE and Embase. Primary outcomes were brain infarct size, motor, and cognitive function. Data for meta‐analysis were synthesized and expressed as standardized mean difference (SMD) with 95% confidence intervals (CI), using a random effects model. We also reported secondary outcomes including NSC survival, migration, differentiation, and effect on neuroinflammation. Eighteen studies met inclusion criteria. NSC administration decreased infarct size (SMD 1.09; CI: 0.44, 1.74, P = .001; I² = 74%) improved motor function measured via the impaired forelimb preference test (SMD 2.27; CI: 0.85, 3.69, P = .002; I² = 86%) and the rotarod test (SMD 1.88; CI: 0.09, 3.67, P = .04; I² = 95%). Additionally, NSCs improved cognitive function measured via the Morris water maze test (SMD of 2.41; CI: 1.16, 3.66, P = .0002; I² = 81%). Preclinical evidence suggests that NSC therapy is promising for the treatment of perinatal brain injury. We have identified key knowledge gaps, including the lack of large animal studies and uncertainty regarding the necessity of immunosuppression for NSC transplantation in neonates. These knowledge gaps should be addressed before NSC treatment can effectively progress to clinical trial.

Neuroprotection offered by mesenchymal stem cells in perinatal brain injury: Role of mitochondria, inflammation, and reactive oxygen species

Preclinical studies have shown that mesenchymal stem cells have a positive effect in perinatal brain injury models. The mechanisms that cause these neurotherapeutic effects are not entirely intelligible. Mitochondrial damage, inflammation, and reactive oxygen species are considered to be critically involved in the development of injury. Mesenchymal stem cells have immunomodulatory action and exert mitoprotective effects which attenuate production of reactive oxygen species and promote restoration of tissue function and metabolism after perinatal insults. This review summarizes the present state, the underlying causes, challenges and possibilities for effective clinical translation of mesenchymal stem cell therapy.

Overexpression of long non-coding RNA H19 relieves hypoxia-induced injury by down-regulating microRNA-107 in neural stem cells

BACKGROUND

Neonatal hypoxia-ischemia (HI) is one of the commonest conditions which seriously influences the development of infants' nervous system and causes series of neurological sequelaes. The aim of the present study was to analyze the potential regulatory mechanism of long non-coding (lnc) RNA H19 under hypoxia conditions.

METHODS

Neural stem cells (NSCs) were incubated in hypoxic conditions for 8 h to induce hypoxia injury. qRT-PCR was performed to detect H19 or micro (miR)-107 expression. Cell Counting Kit-8 (CCK-8) assay and Annexin V-FITC/PI staining assay were employed to detect the effects of hypoxia on cell viability and apoptosis, respectively. Moreover, NSCs were transfected with H19 overexpressing plasmid or shRNA-H19 and then subjected to hypoxia treatment. The effects of H19/miR-107 on NSC cell biological behaviors were confirmed. Furthermore, the signaling pathways involved in HI were analyzed using western blot.

RESULTS

Hypoxia treatment restrained cell viability and induced cell apoptosis in NSCs. Overexpression of lncRNA H19 attenuated hypoxia-induced NSCs injury, while knockdown of lncRNA H19 aggravated NSCs injury. Further experiments suggested that miR-107 up-regulation reversed the effects of lncRNA H19 overexpression on NSCs. Moreover, the activation of Wnt/β-catenin and PI3K/AKT pathways triggered by H19 were reversed by miR-107 up-regulation in hypoxia-treated NSCs.

CONCLUSION

LncRNA H19 overexpression attenuated hypoxia-induced NSCs injury and promoted activation of Wnt/β-catenin and PI3K/AKT pathways through downregulating miR-107.

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.

Preterm Brain Injury, Antenatal Triggers, and Therapeutics: Timing Is Key

With a worldwide incidence of 15 million cases, preterm birth is a major contributor to neonatal mortality and morbidity, and concomitant social and economic burden Preterm infants are predisposed to life-long neurological disorders due to the immaturity of the brain. The risks are inversely proportional to maturity at birth. In the majority of extremely preterm infants (<28 weeks' gestation), perinatal brain injury is associated with exposure to multiple inflammatory perinatal triggers that include antenatal infection (i.e., chorioamnionitis), hypoxia-ischemia, and various postnatal injurious triggers (i.e., oxidative stress, sepsis, mechanical ventilation, hemodynamic instability). These perinatal insults cause a self-perpetuating cascade of peripheral and cerebral inflammation that plays a critical role in the etiology of diffuse white and grey matter injuries that underlies a spectrum of connectivity deficits in survivors from extremely preterm birth. This review focuses on chorioamnionitis and hypoxia-ischemia, which are two important antenatal risk factors for preterm brain injury, and highlights the latest insights on its pathophysiology, potential treatment, and future perspectives to narrow the translational gap between preclinical research and clinical applications.

Transfer of mitochondria from mesenchymal stem cells derived from induced pluripotent stem cells attenuates hypoxia-ischemia-induced mitochondrial dysfunction in PC12 cells

Mitochondrial dysfunction in neurons has been implicated in hypoxia-ischemia-induced brain injury. Although mesenchymal stem cell therapy has emerged as a novel treatment for this pathology, the mechanisms are not fully understood. To address this issue, we first co-cultured 1.5 × 10⁵ PC12 cells with mesenchymal stem cells that were derived from induced pluripotent stem cells at a ratio of 1:1, and then intervened with cobalt chloride (CoCl₂) for 24 hours. Reactive oxygen species in PC12 cells was measured by Mito-sox. Mitochondrial membrane potential (?Ψm) in PC12 cells was determined by JC-1 staining. Apoptosis of PC12 cells was detected by terminal deoxynucleotidal transferase-mediated dUTP nick end-labeling staining. Mitochondrial morphology in PC12 cells was examined by transmission electron microscopy. Transfer of mitochondria from the mesenchymal stem cells derived from induced pluripotent stem cells to damaged PC12 cells was measured by flow cytometry. Mesenchymal stem cells were induced from pluripotent stem cells by lentivirus infection containing green fluorescent protein in mitochondria. Then they were co-cultured with PC12 cells in Transwell chambers and treated with CoCl₂ for 24 hours to detect adenosine triphosphate level in PC12 cells. CoCl₂-induced PC12 cell damage was dose-dependent. Co-culture with mesenchymal stem cells significantly reduced apoptosis and restored ?Ψm in the injured PC12 cells under CoCl₂ challenge. Co-culture with mesenchymal stem cells ameliorated mitochondrial swelling, the disappearance of cristae, and chromatin margination in the injured PC12 cells. After direct co-culture, mitochondrial transfer from the mesenchymal stem cells stem cells to PC12 cells was detected via formed tunneling nanotubes between these two types of cells. The transfer efficiency was greatly enhanced in the presence of CoCl₂. More importantly, inhibition of tunneling nanotubes partially abrogated the beneficial effects of mesenchymal stem cells on CoCl₂-induced PC12 cell injury. Mesenchymal stem cells reduced CoCl₂-induced PC12 cell injury and these effects were in part due to efficacious mitochondrial transfer.

Mouse Bone Marrow-Derived Mesenchymal Stem Cells Alleviate Perinatal Brain Injury Via a CD8+ T Cell Mechanism in a Model of Intrauterine Inflammation

The objective of this study was to determine if mouse bone marrow-derived mesenchymal stem cells (BMMSCs) ameliorate preterm birth and perinatal brain injury induced by intrauterine inflammation (IUI). A mouse model of IUI-induced perinatal brain injury at embryonic (E) day 17 was utilized. BMMSCs were derived from GFP-transgenic mice and phenotypically confirmed to be CD44⁺, Sca-1⁺, CD45^-, CD34^-, CD11b^-, and CD11c^- by flow cytometry and sorted by fluorescence-activated cell sorting (FACS). Dams were assigned to four groups: phosphate-buffered saline (PBS) + PBS, PBS + BMMSCs, lipopolysaccharide (LPS) + PBS, and LPS + BMMSCs. Following maternal IUI, there was a significant increase in CD8⁺ T cells in the placentas. Maternally administered BMMSCs trafficked to the fetal side of the placenta and resulted in significantly decreased placental CD8⁺ T cells. Furthermore, fetal trafficking of maternally administered BMMSCs correlated with an improved performance on offspring neurobehavioral testing in LPS + BMMSC group compared with LPS + PBS group. Our data support that maternal administration of BMMSCs can alleviate perinatal inflammation-induced brain injury and improve neurobehavioral outcomes in the offspring via CD8⁺ T cell immunomodulation at the feto-placental interface.

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.

Quercetin attenuates hypoxia-ischemia induced brain injury in neonatal rats by inhibiting TLR4/NF-κB signaling pathway

Neonatal hypoxic ischemia (HI) is a kind of brain damage that occurs when an infant's brain does not receive enough oxygen and blood. The unrepairable damage leads to newborn death and short/long term brain dysfunctions. Due to the complicated causes and the variety of brain damages, there is no definitive treatment of neonatal HI. In this study, we set up a HI injury model of newborn rat and administrated Quercetin (Que) to treat rat pups before and after HI injury. We performed immunohistochemistry, quantitative PCR and immunoblot experiments to examine whether Que. has a role in attenuating brain injury after HI. We found that Que. treatment could clearly attenuate cortical cell apoptosis, as well as suppress apoptosis marker Bax, and activate anti-apoptosis marker Bcl-2. Moreover, Que. treatment decreased the number of cortical cells microgliosis and astrogliosis induced by HI injury. Furthermore, Que. treatment decreased cortical inflammation. Finally, it is suggested that Que. played a neuroprotective function on HI brain injury via inhibiting the TLR4/NF-κB signaling pathway. From these results, we conclude that Que. treatment may be a used as a therapeutic drug to prevent and decrease the newborn brain damage caused by HI.

Dysmaturation of Premature Brain: Importance, Cellular Mechanisms, and Potential Interventions

Prematurity, especially preterm birth (less than 32 weeks' gestation), is common and associated with high rates of both survival and neurodevelopmental disability, especially apparent in cognitive spheres. The neuropathological substrate of this disability is now recognized to be related to a variety of dysmaturational disturbances of the brain. These disturbances follow initial brain injury, particularly cerebral white matter injury, and involve many of the extraordinary array of developmental events active in cerebral white and gray matter structures during the premature period. This review delineates these developmental events and the dysmaturational disturbances that occur in premature infants. The cellular mechanisms involved in the genesis of the dysmaturation are emphasized, with particular focus on the preoligodendrocyte. A central role for the diffusely distributed activated microglia and reactive astrocytes in the dysmaturation is now apparent. As these dysmaturational cellular mechanisms appear to occur over a relatively long time window, interventions to prevent or ameliorate the dysmaturation, that is, neurorestorative interventions, seem possible. Such interventions include pharmacologic agents, especially erythropoietin, and particular attention has also been paid to such nutritional factors as quality and source of milk, breastfeeding, polyunsaturated fatty acids, iron, and zinc. Recent studies also suggest a potent role for interventions directed at various experiential factors in the neonatal period and infancy, i.e., provision of optimal auditory and visual exposures, minimization of pain and stress, and a variety of other means of environmental behavioral enrichment, in enhancing brain development.

Cord blood research, banking, and transplantation: achievements, challenges, and perspectives

The first hematopoietic transplant in which umbilical cord blood (UCB) was used as the source of hematopoietic cells was performed in October 1988. Since then, significant achievements have been reported in terms of our understanding of the biology of UCB-derived hematopoietic stem (HSCs) and progenitor (HPCs) cells. Over 40,000 UCB transplants (UCBTs) have been performed, in both children and adults, for the treatment of many different diseases, including hematologic, metabolic, immunologic, neoplastic, and neurologic disorders. In addition, cord blood banking has been developed to the point that around 800,000 units are being stored in public banks and more than 4 million units in private banks worldwide. During these 30 years, research in the UCB field has transformed the hematopoietic transplantation arena. Today, scientific and clinical teams are still working on different ways to improve and expand the use of UCB cells. A major effort has been focused on enhancing engraftment to potentially reduce risk of infection and cost. To that end, we have to understand in detail the molecular mechanisms controlling stem cell self-renewal that may lead to the development of ex vivo systems for HSCs expansion, characterize the mechanisms regulating the homing of HSCs and HPCs, and determine the relative place of UCBTs, as compared to other sources. These challenges will be met by encouraging innovative research on the basic biology of HSCs and HPCs, developing novel clinical trials, and improving UCB banking both in the public and private arenas.

Delayed intranasal infusion of human amnion epithelial cells improves white matter maturation after asphyxia in preterm fetal sheep

Perinatal hypoxic-ischemic (HI) brain injury remains highly associated with neurodevelopmental disability after preterm birth. There is increasing evidence that disability is linked with impaired white matter maturation, but there is no specific treatment. In this study, we evaluated whether, in preterm fetal sheep, delayed intranasal infusion of human amnion epithelial cells (hAECs) given 1, 3 and 10 days after severe HI, induced by umbilical cord occlusion for 25 min, can restore white matter maturation or reduce delayed cell loss. After 21 days recovery, asphyxia was associated with reduced electroencephalographic (EEG) maturation, brain weight and cortical area, impaired maturation of oligodendrocytes (OLs), no significant loss of total OLs but a marked reduction in immature/mature OLs and reduced myelination. Intranasal infusion of hAECs was associated with improved brain weight and restoration of immature/mature OLs and fractional area of myelin basic protein, with reduced microglia and astrogliosis. Cortical EEG frequency distribution was partially improved, with reduced loss of cortical area, and attenuated cleaved-caspase-3 expression and microgliosis. Neuronal survival in deep grey matter nuclei was improved, with reduced microglia, astrogliosis and cleaved-caspase-3-positive apoptosis. These findings suggest that delayed intranasal hAEC administration has potential to alleviate chronic dysmaturation after perinatal HI.

Emergent Prophylactic, Reparative and Restorative Brain Interventions for Infants Born Preterm With Cerebral Palsy

Worldwide, an estimated 15 million babies are born preterm (<37 weeks' gestation) every year. Despite significant improvements in survival rates, preterm infants often face a lifetime of neurodevelopmental disability including cognitive, behavioral, and motor impairments. Indeed, prematurity remains the largest risk factor for the development of cerebral palsy. The developing brain of the preterm infant is particularly fragile; preterm babies exhibit varying severities of cerebral palsy arising from reductions in both cerebral white and gray matter volumes, as well as altered brain microstructure and connectivity. Current intensive care therapies aim to optimize cardiovascular and respiratory function to protect the brain from injury by preserving oxygenation and blood flow. If a brain injury does occur, definitive diagnosis of cerebral palsy in the first few hours and weeks of life is difficult, especially when the lesions are subtle and not apparent on cranial ultrasound. However, early diagnosis of mildly affected infants is critical, because these are the patients most likely to respond to emergent treatments inducing neuroplasticity via high-intensity motor training programs and regenerative therapies involving stem cells. A current controversy is whether to test universal treatment in all infants at risk of brain injury, accepting that some patients never required treatment, because the perceived potential benefits outweigh the risk of harm. Versus, waiting for a diagnosis before commencing targeted treatment for infants with a brain injury, and potentially missing the therapeutic window. In this review, we discuss the emerging prophylactic, reparative, and restorative brain interventions for infants born preterm, who are at high risk of developing cerebral palsy. We examine the current evidence, considering the timing of the intervention with relation to the proposed mechanism/s of action. Finally, we consider the development of novel markers of preterm brain injury, which will undoubtedly lead to improved diagnostic and prognostic capability, and more accurate instruments to assess the efficacy of emerging interventions for this most vulnerable group of infants.

Umbilical cord mesenchymal stem cells and umbilical cord blood mononuclear cells improve neonatal rat memory after hypoxia-ischemia

Current treatment options for hypoxic-ischemic encephalopathy (HIE) are limited. Human umbilical cord mesenchymal stem cells (UC-MSCs) and cord blood mononuclear cells (CB-MNCs) offer great potential for the treatment of many neurological diseases. The aim of the present study was to identify which cell type is more effective for the treatment of HIE. PKH26-labeled UC-MSCs and CB-MNCs were transplanted into rats with hypoxia-ischemia (HI)-induced brain damage. Apoptotic cell numbers in the brain, as labeled by TUNEL, were assessed. Myelination and gliosis were investigated using myelin basic protein and glial fibrillary acidic protein immunohistochemistry, respectively. The Morris water maze was used to assess animal learning abilities. Our data show that transplantation of UC-MSCs or CB-MNCs after HI reduced astrogliosis, prevented neuronal loss in the striatum, and markedly improved functional brain outcomes after a 28-day recovery period. Moreover, treatment with CB-MNCs increased the proportion of mature oligodendrocytes and improved myelination in cortical areas. Both UC-MSCs and CB-MNCs may result in the recovery of neurological function in HI rats. Based on our data, UC-MSCs and UCB-MNCs may be particularly effective stem cell subsets for treatment of neonatal HIE.

Neonatal encephalopathy and hypoxic-ischemic encephalopathy

Acute hypoxic-ischemic encephalopathy around the time of birth remains a major cause of death and life-long disability. The key insight that led to the modern revival of studies of neuroprotection was that, after profound asphyxia, many brain cells show initial recovery from the insult during a short "latent" phase, typically lasting approximately 6h, only to die hours to days later after a "secondary" deterioration characterized by seizures, cytotoxic edema, and progressive failure of cerebral oxidative metabolism. Studies designed around this framework showed that mild hypothermia initiated as early as possible before the onset of secondary deterioration and continued for a sufficient duration to allow the secondary deterioration to resolve is associated with potent, long-lasting neuroprotection. There is now compelling evidence from randomized controlled trials that mild to moderate induced hypothermia significantly improves survival and neurodevelopmental outcomes in infancy and mid-childhood.

The fetus at the tipping point: modifying the outcome of fetal asphyxia

Brain injury around birth is associated with nearly half of all cases of cerebral palsy. Although brain injury is multifactorial, particularly after preterm birth, acute hypoxia-ischaemia is a major contributor to injury. It is now well established that the severity of injury after hypoxia-ischaemia is determined by a dynamic balance between injurious and protective processes. In addition, mothers who are at risk of premature delivery have high rates of diabetes and antepartum infection/inflammation and are almost universally given treatments such as antenatal glucocorticoids and magnesium sulphate to reduce the risk of death and complications after preterm birth. We review evidence that these common factors affect responses to fetal asphyxia, often in unexpected ways. For example, glucocorticoid exposure dramatically increases delayed cell loss after acute hypoxia-ischaemia, largely through secondary hyperglycaemia. This critical new information is important to understand the effects of clinical treatments of women whose fetuses are at risk of perinatal asphyxia.

Interaction between hypothermia and delayed mesenchymal stem cell therapy in neonatal hypoxic-ischemic brain injury

Acute hypothermia treatment (HT) is the only clinically established intervention following neonatal hypoxic-ischemic brain injury. However, almost half of all cooled infants still die or suffer from long-lasting neurological impairments. Regenerative therapies, such as mesenchymal stem cells (MSC) appear promising as adjuvant therapy. In the present study, we hypothesized that HT combined with delayed MSC therapy results in augmented protection, improving long-term neurological outcome. Postnatal day 9 (P9) C57BL/6 mice were exposed to hypoxia-ischemia followed by 4 h HT. Murine bone marrow-derived MSC (1 × 10⁶ cells/animal) were administered intranasally at P12. Cytokine and growth factor levels were assessed by ELISA and Luminex® multiplex assay 24 h following MSC delivery. One week after HI, tissue injury and neuroinflammatory responses were determined by immunohistochemistry and western blot. Long-term motor-cognitive outcome was assessed 5 weeks post injury. MSC responses to the brains' environment were evaluated by gene expression analysis in MSC, co-cultured with brain homogenates isolated at P12. Both, MSC and HT improved motor deficits, while cognitive function could only be restored by MSC. Compared to each single therapy, combined treatment led to increased long-lasting motor-cognitive deficits and exacerbated brain injury, accompanied by enhanced endothelial activation and peripheral immune cell infiltration. MSC co-cultured with brain extracts of HT-treated animals revealed increased pro-inflammatory cytokine and decreased growth factor expression. In vivo protein analysis showed higher pro-inflammatory cytokine levels after combined treatment compared to single therapy. Furthermore, HI-induced increase in growth factors was normalized to control levels by HT and MSC single therapy, while the combination induced a further decline below control levels. Our results suggest that alteration of the brains' microenvironment by acute HT modulates MSC function resulting in a pro-inflammatory environment combined with alteration of the homeostatic growth factor milieu in the neonatal hypoxic-ischemic brain. This study delineates potential unexpected side effects of cell-based therapies as add-on therapy for acute hypothermia treatment.

Human Amniotic Fluid Stem Cells: Therapeutic Potential for Perinatal Patients with Intractable Neurological Disease

Mesenchymal stem cells (MSCs) have generated great interest in the fields of regenerative medicine and immunotherapy because of their unique biological properties. Among MSCs, amniotic fluid stem cells (AFS) have a number of characteristics that make them attractive candidates for tissue engineering and cell replacement strategies, particularly for perinatal medicine. If various neonatal conditions, including birth asphyxia, preterm birth, and congenital abnormalities, which result in long-lasting severe impairments, could be predicted during pregnancy, it would allow collection of small samples of amniotic fluid cells by amniocentesis. In vitro culture of these autologous AFS during pregnancy would make them available for use soon after birth. Hypoxic-ischemic encephalopathy (HIE) and myelomeningocele (MMC) are neonatal conditions that cause permanent neurological disability, for which the treatment options are extremely limited. Experiments using animal models of HIE and MMC and human clinical trials have demonstrated that MSCs, including AFS, have beneficial effects on the central nervous system through paracrine influences, indicating that autologous AFS treatment may be applicable for intractable neurological diseases, including HIE and MMC, during the perinatal period. In this review, we focus on recent research related to the therapeutic potential of AFS for perinatal neurological diseases such as HIE and MMC.

Neuroprotection of the hypoxic-ischemic mouse brain by human CD117+CD90+CD105+ amniotic fluid stem cells

Human amniotic fluid contains two morphologically-distinct sub-populations of stem cells with regenerative potential, spindle-shaped (SS-hAFSCs) and round-shaped human amniotic fluid stem cells (RS-hAFSCs). However, it is unclear whether morphological differences correlate with functionality, and this lack of knowledge limits their translational applications. Here, we show that SS-hAFSCs and RS-hAFSCs differ in their neuro-protective ability, demonstrating that a single contralateral injection of SS-hAFSCs into hypoxic-ischemic P7 mice conferred a 47% reduction in hippocampal tissue loss and 43–45% reduction in TUNEL-positive cells in the hippocampus and striatum 48 hours after the insult, decreased microglial activation and TGFβ1 levels, and prevented demyelination. On the other hand, RS-hAFSCs failed to show such neuro-protective effects. It is possible that SS-hAFSCs exert their neuroprotection via endoglin-dependent inhibition of TGFβ1 signaling in target cells. These findings identify a sub-population of CD117⁺CD90⁺CD105⁺ stem cells as a promising source for the neuro-protection of the developing brain.

The effects of rhEPO intervention for perinatal intrauterine herpes virus infection on preventing brain injury in preterm infants

The ability of recombinant human erythropoietin (rhEPO) to protect preterm infants against perinatal intrauterine herpes virus infection-induced brain injury was studied. In total, 120 women infected with perinatal intrauterine herpes virus were randomized into four groups: A, B, C and D, and were given 1,500 IU (mother, pre-partum), 3,000 IU (mother, pre-partum), 250 IU/kg (infant, post-natal), and no rhEPO, respectively. Hemoglobin (Hb), reticulocyte (Ret), hematocrit (Hct), neuron specific enolase (NSE), myelin basic protein (MBP), and S100 protein B (S100B) levels were measured immediately (T₀) and at 1 week (T₁), 2 weeks (T₂), and 4 weeks (T₃) post-delivery. Linear regression analysis was performed to analyze inter-indicator correlation, and ROC risk models were established to determine the predictive value of Hb, Ret and Hct for brain injury immediately after delivery. The brain injury incidence rate of group A (10%) was significantly lower than group D (33.3%) and group B (6.7%) significantly lower than groups C (26.7%) and D. At T₀, Hb, Ret and Hct in groups A and B were significantly higher than in group C and D, while from T₁ to T₃, groups A, B and C showed significantly higher values than group D. NSE, MBP and S100B showed an inverse trend, with groups A and B lower at T₀ and groups A, B and C lower from T₁-T₃. Hb and NSE, MBP and S100B were negatively correlated, while no correlation was found between Ret and NSE, MBP and S100B. Finally, Hct and NSE, MBP and S100B were negatively correlated. The optimal cut-off values for Hb and Hct for brain injury diagnosis immediately post-partum were 170 g/l (sensitivity 99%, specificity 95.7%) and 28.5% (sensitivity 79.4%, specificity 100%), respectively. Ret did not show predictive value. In conclusion, pre-partum rhEPO treatment showed greater protective effects than post-natal administration, and this may be the regulation of Hb and Hct levels in post-natal preterm infants. In addition, a dose-dependent effect was displayed.

Repair of neonatal brain injury: bringing stem cell-based therapy into clinical practice

Hypoxic-ischaemic brain injury is one of most important causes of neonatal mortality and long-term neurological morbidity in infants born at term. At present, only hypothermia in infants with perinatal hypoxic-ischaemic encephalopathy has shown benefit as a neuroprotective strategy. Otherwise, current treatment options for neonatal brain injury mainly focus on controlling (associated) symptoms. Regeneration of the injured neonatal brain with stem cell-based therapies is emerging and experimental results are promising. At present, increasing efforts are made to bring stem cell-based therapies to the clinic. Among all progenitor cell types, mesenchymal stromal (stem) cells seem to be most promising for human use given their neuroregenerative properties and favourable safety profile. This review summarizes the actual state, potential hurdles and possibilities of stem cell-based therapy for neonatal brain injury in the clinical setting. An early version of this paper was presented at the Groningen Early Intervention Meeting which was held in April 2016.

Manufacture and preparation of human placenta-derived mesenchymal stromal cells for local tissue delivery

BACKGROUND

In this study we describe the development of a Current Good Manufacturing Practice (CGMP)-compliant process to isolate, expand and bank placenta-derived mesenchymal stromal cells (PMSCs) for use as stem cell therapy. We characterize the viability, proliferation and neuroprotective secretory profile of PMSCs seeded on clinical-grade porcine small intestine submucosa extracellular matrix (SIS-ECM; Cook Biotech).

METHODS

PMSCs were isolated from early gestation placenta chorionic villus tissue via explant culture. Cells were expanded, banked and screened. Purity and expression of markers of pluripotency were determined using flow cytometry. Optimal loading density and viability of PMSCs on SIS-ECM were determined using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell proliferation and fluorescent live/dead assays, respectively. Growth factors secretion was analyzed using enzyme-linked immunosorbent assays (ELISA).

RESULTS

PMSCs were rapidly expanded and banked. Viable Master and Working Cell Banks were stable with minimal decrease in viability at 6 months. All PMSCs were sterile, free from Mycoplasma species, karyotypically normal and had low endotoxin levels. PMSCs were homogeneous by immunophenotyping and expressed little to no pluripotency markers. Optimal loading density on SIS-ECM was 3-5 × 10⁵ cells/cm², and seeded cells were >95% viable. Neurotrophic factor secretion was detectable from PMSCs seeded on plastic and SIS-ECM with variability between donor lots.

DISCUSSION

PMSCs from early gestation placental tissues can be rapidly expanded and banked in stable, viable cell banks that are free from contaminating agents, genetically normal and pure. PMSC delivery can be accomplished by using SIS-ECM, which maintains cell viability and protein secretion. Future work in vivo is necessary to optimize cell seeding and transplantation to maximize therapeutic capabilities.

Concise Review: Mesenchymal Stem Cell Therapy for Pediatric Disease: Perspectives on Success and Potential Improvements

Mesenchymal stem cells (MSCs) represent a potentially revolutionary therapy for a wide variety of pediatric diseases, but the optimal cell-based therapeutics for such diversity have not yet been specified. The published clinical trials for pediatric pulmonary, cardiac, orthopedic, endocrine, neurologic, and hematologic diseases provide evidence that MSCs are indeed efficacious, but the significant heterogeneity in therapeutic approaches between studies raises new questions. The purpose of this review is to stimulate new preclinical and clinical trials to investigate these factors. First, we discuss recent clinical trials for pediatric diseases studying MSCs obtained from bone marrow, umbilical cord and umbilical cord blood, placenta, amniotic fluid, and adipose tissue. We then identify factors, some unique to pediatrics, which must be examined to optimize therapeutic efficacy, including route of administration, dose, timing of administration, the role of ex vivo differentiation, cell culture techniques, donor factors, host factors, and the immunologic implications of allogeneic therapy. Finally, we discuss some of the practicalities of bringing cell-based therapy into the clinic, including regulatory and manufacturing considerations. The aim of this review is to inform future studies seeking to maximize therapeutic efficacy for each disease and for each patient. Stem Cells Translational Medicine 2017;6:539-565.

Neonatal Encephalopathy: Update on Therapeutic Hypothermia and Other Novel Therapeutics

Neonatal encephalopathy (NE) is a major cause of neonatal mortality and morbidity. Therapeutic hypothermia (TH) is standard treatment for newborns at 36 weeks of gestation or greater with intrapartum hypoxia-related NE. Term and late preterm infants with moderate to severe encephalopathy show improved survival and neurodevelopmental outcomes at 18 months of age after TH. TH can increase survival without increasing major disability, rates of an IQ less than 70, or cerebral palsy. Neonates with severe NE remain at risk of death or severe neurodevelopmental impairment. This review discusses the evidence supporting TH for term or near term neonates with NE.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles Protect the Fetal Brain After Hypoxia-Ischemia

Preterm neonates are susceptible to perinatal hypoxic-ischemic brain injury, for which no treatment is available. In a preclinical animal model of hypoxic-ischemic brain injury in ovine fetuses, we have demonstrated the neuroprotective potential of systemically administered mesenchymal stromal cells (MSCs). The mechanism of MSC treatment is unclear but suggested to be paracrine, through secretion of extracellular vesicles (EVs). Therefore, we investigated in this study the protective effects of mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) in a preclinical model of preterm hypoxic-ischemic brain injury. Ovine fetuses were subjected to global hypoxia-ischemia by transient umbilical cord occlusion, followed by in utero intravenous administration of MSC-EVs. The therapeutic effects of MSC-EV administration were assessed by analysis of electrophysiological parameters and histology of the brain. Systemic administration of MSC-EVs improved brain function by reducing the total number and duration of seizures, and by preserving baroreceptor reflex sensitivity. These functional protections were accompanied by a tendency to prevent hypomyelination. Cerebral inflammation remained unaffected by the MSC-EV treatment. Our data demonstrate that MSC-EV treatment might provide a novel strategy to reduce the neurological sequelae following hypoxic-ischemic injury of the preterm brain. Our study results suggest that a cell-free preparation comprising neuroprotective MSC-EVs could substitute MSCs in the treatment of preterm neonates with hypoxic-ischemic brain injury, thereby circumventing the potential risks of systemic administration of living cells.

SIGNIFICANCE

Bone marrow-derived mesenchymal stromal cells (MSCs) show promise in treating hypoxic-ischemic injury of the preterm brain. Study results suggest administration of extracellular vesicles, rather than intact MSCs, is sufficient to exert therapeutic effects and avoids potential concerns associated with administration of living cells. The therapeutic efficacy of systemically administered mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) on hypoxia-ischemia-induced injury was assessed in the preterm ovine brain. Impaired function and structural injury of the fetal brain was improved following global hypoxia-ischemia. A cell-free preparation of MSC-EVs could substitute for the cellular counterpart in the treatment of preterm neonates with hypoxic-ischemic brain injury. This may open new clinical applications for "off-the-shelf" interventions with MSC-EVs.

Stem cell-based therapies for the newborn lung and brain: Possibilities and challenges

There have been substantial advances in neonatal medical care over the past 2 decades that have resulted in the increased survival of very low birth weight infants, survival that in some centers extends to 22 weeks gestational age. Despite these advances, there continues to be significant morbidity associated with extreme preterm birth that includes both short-term and long-term pulmonary and neurologic consequences. No single therapy has proven to be effective in preventing or treating either developmental lung and brain injuries in preterm infants or the hypoxic-ischemic injury that can be inflicted on the full-term brain as a result of in utero or perinatal complications. Stem cell-based therapies are emerging as a potential paradigm-shifting approach for such complex diseases with multifactorial etiologies, but a great deal of work is still required to understand the role of stem/progenitor cells in normal development and in the repair of injured tissue. This review will summarize the biology of the various stem/progenitor cells, their effects on tissue repair in experimental models of lung and brain injury, the recent advances in our understanding of their mechanism of action, and the challenges that remain to be addressed before their eventual application to clinical care.

Stem Cells for Neonatal Brain Disorders

Despite recent advances in neonatal intensive care medicine, neonatal brain injury resulting from intraventricular hemorrhage or hypoxic-ischemic encephalopathy remains a major cause of neonatal mortality and neurologic morbidities in survivors. Several studies have indicated that stem cell therapy is a promising novel therapy for neonatal brain injury resulting from these disorders. This review summarizes recent advances in stem cell research for treating neonatal brain injury due to intraventricular hemorrhage or hypoxic-ischemic encephalopathy with a particular focus on preclinical data, covering important issues for clinical translation such as optimal cell type, route, dose and timing of stem cell therapy, and translation of these preclinical results into a clinical trial.

Stem Cells: Potential Therapy for Neonatal Injury?

Stem cell transplantation (SCT) is an established first-line or adjunctive therapy for a variety of neonatal and adult diseases. New evidence in preclinical models as well as a few human studies show the potential utility of SCT in neuroprotection and in the modulation of inflammatory injury in at risk-neonates. This review briefly summarizes current understanding of human stem cell biology during ontogeny and present recent evidence supporting SCT as a viable approach for postinsult neonatal injury.

Murine model: maternal administration of stem cells for prevention of prematurity

OBJECTIVE

Using a mouse model of intrauterine inflammation, we have demonstrated that exposure to inflammation induces preterm birth and perinatal brain injury. Mesenchymal stem cells (MSCs) have been shown to exhibit immunomodulatory effects in many inflammatory conditions. We hypothesized that treatment with human adipose tissue-derived MSCs may decrease the rate of preterm birth and perinatal brain injury through changes in antiinflammatory and regulatory milieu.

STUDY DESIGN

A mouse model of intrauterine inflammation was used with the following groups: (1) control; (2) intrauterine inflammation (lipopolysaccharide); and (3) intrauterine lipopolysaccharide+intraperitoneal (MSCs). Preterm birth was investigated. Luminex multiplex enzyme-linked immunosorbent assays were performed for protein levels of cytokines in maternal and fetal compartments. Immunofluorescent staining was used to identify and localize MSCs and to examine microglial morphologic condition and neurotoxicity in perinatal brain. Behavioral testing was performed at postnatal day 5.

RESULTS

Pretreatment with MSCs significantly decreased the rate of preterm birth by 21% compared with the lipopolysaccharide group (P<.01). Pretreatment was associated with increased interleukin-10 in maternal serum, increased interleukin-4 in placenta, decreased interleukin-6 in fetal brain (P<.05), decreased microglial activation (P<.05), and decreased fetal neurotoxicity (P<.05). These findings were associated with improved neurobehavioral testing at postnatal day 5 (P<.05). Injected MSCs were localized to placenta.

CONCLUSION

Maternally administered MSCs appear to modulate maternal and fetal immune response to intrauterine inflammation in the model and decrease preterm birth, perinatal brain injury, and motor deficits in offspring mice.

Early gestation chorionic villi-derived stromal cells for fetal tissue engineering

AIM: To investigate the potential for early gestation placenta-derived mesenchymal stromal cells (PMSCs) for fetal tissue engineering.

METHODS: PMSCs were isolated from early gestation chorionic villus tissue by explant culture. Chorionic villus sampling (CVS)-size tissue samples (mean = 35.93 mg) were used to test the feasibility of obtaining large cell numbers from CVS within a clinically relevant timeframe. We characterized PMSCs isolated from 6 donor placentas by flow cytometry immunophenotyping, multipotency assays, and through immunofluorescent staining. Protein secretion from PMSCs was examined using two cytokine array assays capable of probing for over 70 factors in total. Delivery vehicle compatibility of PMSCs was determined using three common scaffold systems: fibrin glue, collagen hydrogel, and biodegradable nanofibrous scaffolds made from a combination of polylactic acid (PLA) and poly(lactic-co-glycolic acid) (PLGA). Viral transduction of PMSCs was performed using a Luciferase-GFP-containing lentiviral vector and efficiency of transduction was tested by fluorescent microscopy and flow cytometry analysis.

RESULTS: We determined that an average of 2.09 × 10⁶ (SD ± 8.59 × 10⁵) PMSCs could be obtained from CVS-size tissue samples within 30 d (mean = 27 d, SD ± 2.28), indicating that therapeutic numbers of cells can be rapidly expanded from very limited masses of tissue. Immunophenotyping by flow cytometry demonstrated that PMSCs were positive for MSC markers CD105, CD90, CD73, CD44, and CD29, and were negative for hematopoietic and endothelial markers CD45, CD34, and CD31. PMSCs displayed trilineage differentiation capability, and were found to express developmental transcription factors Sox10 and Sox17 as well as neural-related structural proteins NFM, Nestin, and S100β. Cytokine arrays revealed a robust and extensive profile of PMSC-secreted cytokines and growth factors, and detected 34 factors with spot density values exceeding 10³. Detected factors had widely diverse functions that include modulation of angiogenesis and immune response, cell chemotaxis, cell proliferation, blood vessel maturation and homeostasis, modulation of insulin-like growth factor activity, neuroprotection, extracellular matrix degradation and even blood coagulation. Importantly, PMSCs were also determined to be compatible with both biological and synthetic material-based delivery vehicles such as collagen and fibrin hydrogels, and biodegradable nanofiber scaffolds made from a combination of PLA and PLGA. Finally, we demonstrated that PMSCs can be efficiently transduced (> 95%) with a Luciferase-GFP-containing lentiviral vector for future in vivo cell tracking after transplantation.

CONCLUSION: Our findings indicate that PMSCs represent a unique source of cells that can be effectively utilized for in utero cell therapy and tissue engineering.

Neural stem cells: are they the hope of a better life for patients with fetal-onset hydrocephalus?

I was honored to be awarded the Casey Holter Essay Prize in 2013 by the Society for Research into Hydrocephalus and Spina Bifida. The purpose of the prize is to encourage original thinking in a way to improve the care of individuals with spina bifida and hydrocephalus. Having kept this purpose in mind, I have chosen the title: Neural stem cells, are they the hope of a better life for patients with fetal-onset hydrocephalus? The aim is to review and discuss some of the most recent and relevant findings regarding mechanisms leading to both hydrocephalus and abnormal neuro/gliogenesis. By looking at these outcome studies, it is hoped that we will recognize the potential use of neural stem cells in the treatment of hydrocephalus, and so prevent the disease or diminish/repair the associated brain damage.