Intranasal administration of human MSC for ischemic brain injury in the mouse: in vitro and in vivo neuroregenerative functions

Intranasal therapies for neonatal hypoxic-ischemic encephalopathy: Systematic review, synthesis, and implications for global accessibility to care

Neonatal hypoxic-ischemic encephalopathy (HIE) is the leading cause of neurodevelopmental morbidity in term infants worldwide. Incidence of HIE is highest in low and middle-income communities with minimal access to neonatal intensive care and an underdeveloped infrastructure for advanced neurologic interventions. Moreover, therapeutic hypothermia, standard of care for HIE in high resourced settings, is shown to be ineffective in low and middle-income communities. With their low cost, ease of administration, and capacity to potently target the central nervous system, intranasal therapies pose a unique opportunity to be a more globally accessible treatment for neonatal HIE. Intranasal experimental therapeutics have been studied in both rodent and piglet models, but no intranasal therapeutics for neonatal HIE have undergone human clinical trials. Additional research must be done to expand the array of treatments available for use as intranasal therapies for neonatal HIE thus improving the neurologic outcomes of infants worldwide.

Neuroprotection of Stem Cells Against Ischemic Brain Injury: From Bench to Clinic

Neurological injuries can have numerous debilitating effects on functional status including sensorimotor deficits, cognitive impairment, and behavioral symptoms. Despite the disease burden, treatment options remain limited. Current pharmacological interventions are targeted at symptom management but are ineffective in reversing ischemic brain damage. Stem cell therapy for ischemic brain injury has shown promising preclinical and clinical results and has attracted attention as a potential therapeutic option. Various stem cell sources (embryonic, mesenchymal/bone marrow, and neural stem cells) have been investigated. This review provides an overview of the advances made in our understanding of the various types of stem cells and progress made in the use of these stem cells for the treatment of ischemic brain injuries. In particular, the use of stem cell therapy in global cerebral ischemia following cardiac arrest and in focal cerebral ischemia after ischemic stroke are discussed. The proposed mechanisms of stem cells' neuroprotective effects in animal models (rat/mice, pig/swine) and other clinical studies, different routes of administration (intravenous/intra-arterial/intracerebroventricular/intranasal/intraperitoneal/intracranial) and stem cell preconditioning are discussed. Much of the promising data on stem cell therapies after ischemic brain injury remains in the experimental stage and several limitations remain unsettled. Future investigation is needed to further assess the safety and efficacy and to overcome the remaining obstacles.

Mesenchymal Stromal Cell therapy for Hypoxic Ischemic Encephalopathy: Future directions for combination therapy with hypothermia and/or melatonin

Hypoxic ischemic encephalopathy (HIE) remains a leading cause of neonatal mortality and lifelong disability across the world. While therapeutic hypothermia (HT) is beneficial, it is only partially protective and adjuvant treatments that further improve outcomes are urgently needed. In high-income countries where HT is standard care, novel treatments are tested in conjunction with HT. Mesenchymal stromal cells (MSC) represent a paradigm shift in brain protection, uniquely adapting to the host cellular microenvironment. MSC have low immunogenicity and potent paracrine effects stimulating the host tissue repair and regeneration and reducing inflammation and apoptosis. Preclinical studies in perinatal brain injury suggest that MSC are beneficial after hypoxia-ischemia (HI) and most preclinical studies of MSC with HT show protection. Preclinical and early phase clinical trials have shown that allogenic administration of MSC to neonates with perinatal stroke and HIE is safe and feasible but further safety and efficacy studies of HT with MSC in these populations are needed. Combination therapies that target all stages of the evolution of injury after HI (eg HT, melatonin and MSC) show promise for improving outcomes in HIE.

Dietary LPC-Bound n-3 LCPUFA Protects against Neonatal Brain Injury in Mice but Does Not Enhance Stem Cell Therapy

Neonatal hypoxic-ischemic (HI) brain injury is a prominent cause of neurological morbidity, urging the development of novel therapies. Interventions with n-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) and mesenchymal stem cells (MSCs) provide neuroprotection and neuroregeneration in neonatal HI animal models. While lysophosphatidylcholine (LPC)-bound n-3 LCPUFAs enhance brain incorporation, their effect on HI brain injury remains unstudied. This study investigates the efficacy of oral LPC-n-3 LCPUFAs from Lysoveta following neonatal HI in mice and explores potential additive effects in combination with MSC therapy. HI was induced in 9-day-old C57BL/6 mice and Lysoveta was orally supplemented for 7 subsequent days, with or without intranasal MSCs at 3 days post-HI. At 21-28 days post-HI, functional outcome was determined using cylinder rearing, novel object recognition, and open field tasks, followed by the assessment of gray (MAP2) and white (MBP) matter injury. Oral Lysoveta diminished gray and white matter injury but did not ameliorate functional deficits following HI. Lysoveta did not further enhance the therapeutic potential of MSC therapy. In vitro, Lysoveta protected SH-SY5Y neurons against oxidative stress. In conclusion, short-term oral administration of Lysoveta LPC-n-3 LCPUFAs provides neuroprotection against neonatal HI by mitigating oxidative stress injury but does not augment the efficacy of MSC therapy.

Modifying the Secretome of Mesenchymal Stem Cells Prolongs the Regenerative Treatment Window for Encephalopathy of Prematurity

Clinical treatment options to combat Encephalopathy of Prematurity (EoP) are still lacking. We, and others, have proposed (intranasal) mesenchymal stem cells (MSCs) as a potent therapeutic strategy to boost white matter repair in the injured preterm brain. Using a double-hit mouse model of diffuse white matter injury, we previously showed that the efficacy of MSC treatment was time dependent, with a significant decrease in functional and histological improvements after the postponement of cell administration. In this follow-up study, we aimed to investigate the mechanisms underlying this loss of therapeutic efficacy. Additionally, we optimized the regenerative potential of MSCs by means of genetic engineering with the transient hypersecretion of beneficial factors, in order to prolong the treatment window. Though the cerebral expression of known chemoattractants was stable over time, the migration of MSCs to the injured brain was partially impaired. Moreover, using a primary oligodendrocyte (OL) culture, we showed that the rescue of injured OLs was reduced after delayed MSC coculture. Cocultures of modified MSCs, hypersecreting IGF1, LIF, IL11, or IL10, with primary microglia and OLs, revealed a superior treatment efficacy over naïve MSCs. Additionally, we showed that the delayed intranasal administration of IGF1-, LIF-, or IL11-hypersecreting MSCs, improved myelination and the functional outcome in EoP mice. In conclusion, the impaired migration and regenerative capacity of intranasally applied MSCs likely underlie the observed loss of efficacy after delayed treatment. The intranasal administration of IGF1-, LIF-, or IL11-hypersecreting MSCs, is a promising optimization strategy to prolong the window for effective MSC treatment in preterm infants with EoP.

CXCL10 is a crucial chemoattractant for efficient intranasal delivery of mesenchymal stem cells to the neonatal hypoxic-ischemic brain

BACKGROUND

Hypoxic-Ischemic Encephalopathy (HIE) is a leading cause of mortality and morbidity in newborns. Recent research has shown promise in using intranasal mesenchymal stem cell (MSC) therapy if administered within 10 days after Hypoxia-Ischemia (HI) in neonatal mice. MSCs migrate from the nasal cavity to the cerebral lesion in response to chemotactic cues. Which exact chemokines are crucial for MSC guidance to the HI lesion is currently not fully understood. This study investigates the role of CXCL10 in MSC migration towards the HI-injured brain.

METHODS

HI was induced in male and female 9-day-old C57BL/6 mice followed by intranasal MSC treatment at day 10 or 17 post-HI. CXCL10 protein levels, PKH26-labeled MSCs and lesion size were assessed by ELISA, immunofluorescent imaging and MAP2 staining respectively. At day 17 post-HI, when CXCL10 levels were reduced, intracranial CXCL10 injection and intranasal PKH26-labeled MSC administration were combined to assess CXCL10-guided MSC migration. MSC treatment efficacy was evaluated after 18 days, measuring lesion size, motor outcome (cylinder rearing task), glial scarring (GFAP staining) and neuronal density (NeuN staining) around the lesion. Expression of the receptor for CXCL10, i.e. CXCR3, on MSCs was confirmed by qPCR and Western Blot. Moreover, CXCL10-guided MSC migration was assessed through an in vitro transwell migration assay.

RESULTS

Intranasal MSC treatment at day 17 post-HI did not reduce lesion size in contrast to earlier treatment timepoints. Cerebral CXCL10 levels were significantly decreased at 17 days versus 10 days post-HI and correlated with reduced MSC migration towards the brain. In vitro experiments demonstrated that CXCR3 receptor inhibition prevented CXCL10-guided migration of MSCs. Intracranial CXCL10 injection at day 17 post-HI significantly increased the number of MSCs reaching the lesion which was accompanied by repair of the HI lesion as measured by reduced lesion size and glial scarring, and an increased number of neurons around the lesion.

CONCLUSIONS

This study underscores the crucial role of the chemoattractant CXCL10 in guiding MSCs to the HI lesion after intranasal administration. Strategies to enhance CXCR3-mediated migration of MSCs may improve the efficacy of MSC therapy or extend its regenerative therapeutic window.

Mitochondria-targeted cerium vanadate nanozyme suppressed hypoxia-ischemia injury in neonatal mice via intranasal administration

Oxidative stress is a major obstacle for neurological functional recovery after hypoxia-ischemia (HI) brain damage. Nanozymes with robust anti-oxidative stress properties offer a therapeutic option for HI injury. However, insufficiency of nanozyme accumulation in the HI brain by noninvasive administration hinders their application. Herein, we reported a cerium vanadate (CeVO4) nanozyme to realize a noninvasive therapy for HI brain in neonatal mice by targeting brain neuron mitochondria. CeVO4 nanozyme with superoxide dismutase activity mainly co-located with neuronal mitochondria 1 h after administration. Pre- and post-HI administrations of CeVO4 nanozyme were able to attenuate acute brain injury, by inhibiting caspase-3 activation, microglia activation, and proinflammation cytokine production in the lesioned cortex 2 d after HI injury. Moreover, CeVO4 nanozyme administration led to short- and long-term functional recovery following HI insult without any potential toxicities in peripheral organs of mice even after prolonged delivery for 4 weeks. These beneficial effects of CeVO4 nanozyme were associated with suppressed oxidative stress and up-regulated nuclear factor erythroid-2-related factor 2 (Nrf2) expression. Finally, we found that Nrf2 inhibition with ML385 abolished the protective effects of CeVO4 nanozyme on HI injury. Collectively, this strategy may provide an applicative perspective for CeVO4 nanozyme therapy in HI brain damage via noninvasive delivery.

Stem cells in central nervous system diseases: Promising therapeutic strategies

Central nervous system (CNS) diseases are a leading cause of death and disability. Due to CNS neurons have no self-renewal and regenerative ability as they mature, their loss after injury or disease is irreversible and often leads to functional impairments. Unfortunately, therapeutic options for CNS diseases are still limited, and effective treatments for these notorious diseases are warranted to be explored. At present, stem cell therapy has emerged as a potential therapeutic strategy for improving the prognosis of CNS diseases. Accumulating preclinical and clinical evidences have demonstrated that multiple molecular mechanisms, such as cell replacement, immunoregulation and neurotrophic effect, underlie the use of stem cell therapy for CNS diseases. However, several issues have yet to be addressed to support its clinical application. Thus, this review article aims to summarize the role and underlying mechanisms of stem cell therapy in treating CNS diseases. And it is worthy of further evaluation for the potential therapeutic applications of stem cell treatment in CNS disease.

Roles and therapeutic potential of different extracellular vesicle subtypes on traumatic brain injury

Traumatic brain injury (TBI) is a leading cause of injury-related disability and death around the world, but the clinical stratification, diagnosis, and treatment of complex TBI are limited. Due to their unique properties, extracellular vesicles (EVs) are emerging candidates for being biomarkers of traumatic brain injury as well as serving as potential therapeutic targets. However, the effects of different extracellular vesicle subtypes on the pathophysiology of traumatic brain injury are very different, or potentially even opposite. Before extracellular vesicles can be used as targets for TBI therapy, it is necessary to classify different extracellular vesicle subtypes according to their functions to clarify different strategies for EV-based TBI therapy. The purpose of this review is to discuss contradictory effects of different EV subtypes on TBI, and to propose treatment ideas based on different EV subtypes to maximize their benefits for the recovery of TBI patients. Video Abstract.

Sleeping Beauty transposon system for GDNF overexpression of entrapped stem cells in fibrin hydrogel in a rat model of Parkinson's disease

There is currently no causal treatment available for Parkinson's disease (PD). However, the use of glial cell line-derived neurotrophic factor (GDNF) to provide regenerative effects for neurons is promising. Such approaches require translational delivery systems that are functional in diseased tissue. To do so, we used a non-viral Sleeping Beauty (SB) transposon system to overexpress GDNF in adipose tissue-derived mesenchymal stromal cells (adMSCs). Entrapment of cells in fibrin hydrogel was used to boost potential neurorestorative effects. Functional GDNF-adMSCs were able to secrete 1066.8 ± 169.4 ng GDNF/120,000 cells in vitro. The GDNF-adMSCs were detectable for up to 1 month after transplantation in a mild 6-hydroxydopamine (6-OHDA) hemiparkinson male rat model. Entrapment of GDNF-adMSCs enabled GDNF secretion in surrounding tissue in a more concentrated manner, also tending to prolong GDNF secretion relatively. GDNF-adMSCs entrapped in hydrogel also led to positive immunomodulatory effects via an 83% reduction of regional IL-1β levels compared to the non-entrapped GDNF-adMSC group after 1 month. Furthermore, GDNF-adMSC-treated groups showed higher recovery of tyrosine hydroxylase (TH)-expressing cells, indicating a neuroprotective function, although this was not strong enough to show significant improvement in motor performance. Our findings establish a promising GDNF treatment system in a PD model. Entrapment of GDNF-adMSCs mediated positive immunomodulatory effects. Although the durability of the hydrogel needs to be extended to unlock its full potential for motor improvements, the neuroprotective effects of GDNF were evident and safe. Further motor behavioral tests and other disease models are necessary to evaluate this treatment option adequately.

Intranasally delivered mesenchymal stromal cells decrease glial inflammation early in prion disease

Mesenchymal stromal cells (MSCs) are an intriguing avenue for the treatment of neurological disorders due to their ability to migrate to sites of neuroinflammation and respond to paracrine signaling in those sites by secreting cytokines, growth factors, and other neuromodulators. We potentiated this ability by stimulating MSCs with inflammatory molecules, improving their migratory and secretory properties. We investigated the use of intranasally delivered adipose-derived MSCs (AdMSCs) in combating prion disease in a mouse model. Prion disease is a rare, lethal neurodegenerative disease that results from the misfolding and aggregation of the prion protein. Early signs of this disease include neuroinflammation, activation of microglia, and development of reactive astrocytes. Later stages of disease include development of vacuoles, neuronal loss, abundant aggregated prions, and astrogliosis. We demonstrate the ability of AdMSCs to upregulate anti-inflammatory genes and growth factors when stimulated with tumor necrosis factor alpha (TNFα) or prion-infected brain homogenates. We stimulated AdMSCs with TNFα and performed biweekly intranasal deliveries of AdMSCs on mice that had been intracranially inoculated with mouse-adapted prions. At early stages in disease, animals treated with AdMSCs showed decreased vacuolization throughout the brain. Expression of genes associated with Nuclear Factor-kappa B (NF-κB) and Nod-Like Receptor family pyrin domain containing 3 (NLRP3) inflammasome signaling were decreased in the hippocampus. AdMSC treatment promoted a quiescent state in hippocampal microglia by inducing changes in both number and morphology. Animals that received AdMSCs showed a decrease in both overall and reactive astrocyte number, and morphological changes indicative of homeostatic astrocytes. Although this treatment did not prolong survival or rescue neurons, it demonstrates the benefits of MSCs in combatting neuroinflammation and astrogliosis.

Mechanistic approach of the therapeutic potential of mesenchymal stem cells on brain damage in irradiated mice: emphasis on anti-inflammatory and anti-apoptotic effects

BACKGROUND AND OBJECTIVES

Brain damage which has been induced by radiation generally occurs in radiotherapeutics patients. Stem cell transplantation represents a vital applicant for alleviating neurodegenerative disorders. This work aims at exploring the potential of bone marrow-derived mesenchymal stem cells (BM-MSCs) on brain injury induced by γ radiation in mice and the possible underlying mechanisms were elucidated.

MATERIALS AND METHODS

Mice were allocated into three groups; Group I (Control), Group II (Irradiated control) where mice submitted to 5 Gy of whole-body γ radiation, Group III (Irradiated + BM-MSCs) where mice were intravenously injected of BM-MSCs at a dose of 106 cells/mice 24 h following irradiation. Animals were sacrificed 28 d following exposure to γ radiation.

RESULTS

It was observed that BM-MSCs therapy provided a valuable tissue repair as evidenced by a reduction in inflammatory mediators including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), nuclear factor kappa (NF-κβ), phosphorylated NF-κβ-p65 (P-NF-κβ-p65), interferon-gamma (IFNγ) and monocyte chemoattractant protein-1 (MCP-1) associated with decreased levels of transforming growth factor-β (TGF-β) and vascular endothelial growth factor (VEGF) in brain tissues of irradiated mice. Furthermore, neuronal apoptosis was declined in brain tissues of the BM-MSCs group as remarkable inhibition of caspase-3 and Bax accompanied by elevation of Bcl-2 proteins expression. These results were supported by histopathological investigation.

CONCLUSIONS

In conclusion, BM-MSCs could display a vital rule in alleviating brain injury in radio-therapeutic patients.

Early evolution of glial morphology and inflammatory cytokines following hypoxic-ischemic injury in the newborn piglet brain

Neuroinflammation is a hallmark of hypoxic-ischemic injury and can be characterized by the activation of glial cells and the expression of inflammatory cytokines and chemokines. Interleukin (IL)-1β and tumor necrosis factor (TNF)α are among the best-characterized early response cytokines and are often expressed concurrently. Several types of central nervous system cells secrete IL-1β and TNFα, including microglia, astrocytes, and neurons, and these cytokines convey potent pro-inflammatory actions. Chemokines also play a central role in neuroinflammation by controlling inflammatory cell trafficking. Our aim was to characterise the evolution of early neuroinflammation in the neonatal piglet model of hypoxic-ischemic encephalopathy (HIE). Piglets (< 24 h old) were exposed to HI insult, and recovered to 2, 4, 8, 12 or 24H post-insult. Brain tissue from the frontal cortex and basal ganglia was harvested for assessment of glial cell activation profiles and transcription levels of inflammatory markers in HI piglets with comparison to a control group of newborn piglets. Fluorescence microscopy was used to observe microglia, astrocytes, neurons, degenerating neurons and possibly apoptotic cells, and quantitative polymerase chain reaction was used to measure gene expression of several cytokines and chemokines. HI injury was associated with microglial activation and morphological changes to astrocytes at all time points examined. Gene expression analyses of inflammation-related markers revealed significantly higher expression of pro-inflammatory cytokines tumor necrosis factor-α (TNFα) and interleukin 1 beta (IL-1β), chemokines cxc-chemokine motif ligand (CXCL)8 and CXCL10, and anti-inflammatory cytokine transforming growth factor (TGF)β in every HI group, with some region-specific differences noted. No significant difference was observed in the level of C-X-C chemokine receptor (CCR)5 over time. This high degree of neuroinflammation was associated with a reduction in the number of neurons in piglets at 12H and 24H in the frontal cortex, and the putamen at 12H. This reduction of neurons was not associated with increased numbers of degenerating neurons or potentially apoptotic cells. HI injury triggered a robust early neuroinflammatory response associated with a reduction in neurons in cortical and subcortical regions in our piglet model of HIE. This neuroinflammatory response may be targeted using novel therapeutics to reduce neuropathology in our piglet model of neonatal HIE.

Can Soluble Immune Checkpoint Molecules on Exosomes Mediate Inflammation?

Immune checkpoints (ICPs) are major co-signaling pathways that trigger effector functions in immune cells, with isoforms that are either membrane bound, engaging in direct cell to cell activation locally, or soluble, acting at distant sites by circulating freely or potentially via extracellular vesicles (EVs). Exosomes are small EVs secreted by a variety of cells carrying various proteins and nucleic acids. They are distributed extensively through biological fluids and have major impacts on infectious diseases, cancer, and neuroinflammation. Similarly, ICPs play key roles in a variety of disease conditions and have been extensively utilized as a prognostic tool for various cancers. Herein, we explored if the association between exosomes and ICPs could be a significant contributor of inflammation, particularly in the setting of cancer, neuroinflammation and viral infections, wherein the up regulation in both exosomal proteins and ICPs correlate with immunosuppressive effects. The detailed literature review of existing data highlights the significance and complexity of these two important pathways in mediating cancer and potentiating neuroinflammation via modulating overall immune response. Cells increasingly secret exosomes in response to intracellular signals from invading pathogens or cancerous transformations. These exosomes can carry a variety of cargo including proteins, nucleic acids, cytokines, and receptors/ligands that have functional consequences on recipient cells. Illustration generated using BioRender software.

Mechanisms of Tertiary Neurodegeneration after Neonatal Hypoxic-Ischemic Brain Damage

Neonatal encephalopathy linked to hypoxia-ischemia (H-I) which is regarded as the most important neurological problem of the newborn, can lead to a spectrum of adverse neurodevelopmental outcomes such as cerebral palsy, epilepsy, hyperactivity, cognitive impairment and learning difficulties. There have been numerous reviews that have focused on the epidemiology, diagnosis and treatment of neonatal H-I; however, a topic that is less often considered is the extent to which the injury might worsen over time, which is the focus of this review. Similarly, there have been numerous reviews that have focused on mechanisms that contribute to the acute or subacute injury; however, there is a tertiary phase of recovery that can be defined by cellular and molecular changes that occur many weeks and months after brain injury and this topic has not been the focus of any review for over a decade. Therefore, in this article we review both the clinical and pre-clinical data that show that tertiary neurodegeneration is a significant contributor to the final outcome, especially after mild to moderate injuries. We discuss the contributing roles of apoptosis, necroptosis, autophagy, protein homeostasis, inflammation, microgliosis and astrogliosis. We also review the limited number of studies that have shown that significant neuroprotection and preservation of neurological function can be achieved administering drugs during the period of tertiary neurodegeneration. As the tertiary phase of neurodegeneration is a stage when interventions are eminently feasible, it is our hope that this review will stimulate a new focus on this stage of recovery towards the goal of producing new treatment options for neonatal hypoxic-ischemic encephalopathy.

Therapeutic potential of hair follicle-derived stem cell intranasal transplantation in a rat model of ischemic stroke

BACKGROUND

Stem cell-based therapy has received considerable attention as a potential candidate in the treatment of ischemic stroke; however, employing an appropriate type of stem cells and an effective delivery route are still challenging. In the present study, we investigated the therapeutic effect of safe, noninvasive, and brain-targeted intranasal administration of hair follicle-derived stem cells (HFSCs) in a rat model of ischemic stroke.

METHODS

Stem cells were obtained from the adult rat hair follicles. In experiment 1, stroke was induced by 30 min middle cerebral artery occlusion (MCAO) and stem cells were intranasally transplanted immediately after ischemia. In experiment 2, stroke was induced by 120 min MCAO and stem cells were administered 24 h after cerebral ischemia. In all experimental groups, neurological performance, short-term spatial working memory and infarct volume were assessed. Moreover, relative expression of major trophic factors in the striatum and cortex was evaluated by the quantitative PCR technique. The end point of experiment 1 was day 3 and the end point of experiment 2 was day 15.

RESULTS

In both experiments, intranasal administration of HFSCs improved functional performance and decreased infarct volume compared to the MCAO rats. Furthermore, NeuN and VEGF expression were higher in the transplanted group and stem cell therapy partially prevented BDNF and neurotrophin-3 over-expression induced by cerebral ischemia.

CONCLUSIONS

These findings highlight the curative potential of HFSCs following intranasal transplantation in a rat model of ischemic stroke.

Mesenchymal stem cells for the treatment of cognitive impairment caused by neurological diseases

Patients with neurological diseases often have cognitive impairment, which creates a substantial emotional and economic burden for patients and their families. This issue urgently needs to be addressed. The pathological mechanism of this cognitive impairment is a complicated process that involves a variety of cells and molecules, central nervous system inflammatory reactions, oxidative stress, free radical damage and nerve protection factor-related metabolic disorders. Traditional treatments include neuroprotective agents and analgesic therapy. However, analgesic therapy cannot improve cognitive function, and the blood-brain barrier (BBB) largely blocks neuroprotective agents from entering the central nervous system; therefore, it is very important to find a more effective treatment. Mesenchymal stem cells (MSCs) have anti-inflammatory, anti-apoptotic and immunomodulatory properties and have been proven to play an important role in the treatment of many neurodegenerative diseases. Most importantly, MSCs are likely to cross the BBB. Therefore, MSC therapy is regarded as an important means of ameliorating neurological impairment. The purpose of this review is to summarize recent researches on the treatment of cognitive dysfunction caused by neurological diseases with MSCs.

Combined hypothermia and mesenchymal stem cells in animal models of neonatal hypoxic-ischaemic encephalopathy: a systematic review

BACKGROUND

The objective of this study was to systematically review the literature to determine the effect of combined hypothermia (HTH) and mesenchymal stem cell (MSC) therapy (administered during or immediately before or after HTH) compared with HTH alone on brain injury and neurobehavioural outcomes in animal models of neonatal hypoxic-ischaemic encephalopathy.

METHODS

Primary outcomes assessed were neuropathological measures and neurobehavioural measures of brain outcome. Secondary outcomes were brain protein proinflammatory cytokine status. Risk of bias (ROB) was assessed with the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) ROB assessment tool.

RESULTS

Of 393 studies identified, 3 studies in postnatal day 7 (P7) male Sprague-Dawley rats met the inclusion criteria. Meta-analyses were undertaken for neuropathological measures (apoptotic cells, astrocytes, microglia), neurobehavioral measures (rotarod test and negative geotaxis), and proinflammatory cytokine levels. Two of the three studies scored low or unclear ROB across all measures. Treatment with HTH-MSCs together significantly improved astrocyte optical density by standardised mean difference (SMD) of 0.71 [95% confidence interval (CI) -1.14, -0.28]. No other measures showed significant differences.

CONCLUSIONS

There is insufficient preclinical data to confirm the efficacy of combined HTH-MSC therapy over HTH alone. Future studies should utilise a reporting checklist such as in SYRCLE or Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines to improve reporting standards.

IMPACT

Very few articles investigating the use of MSCs for the treatment of hypoxic-ischaemic encephalopathy are clinically relevant. Continuing to publish studies in models of hypoxic-ischaemic encephalopathy without the inclusion of HTH therapy does not progress the field towards improved clinical outcomes. This study shows that HTH and MSC therapy improves measures of astrogliosis. More studies are required to establish the efficacy of HTH and MSCs on measures of neuropathology and neurobehavior. The reporting of preclinical data in this space could be improved by using reporting checklists such as the SYRCLE or ARRIVE tools.

Mesenchymal Stem Cell Application and Its Therapeutic Mechanisms in Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH), a common lethal subtype of stroke accounting for nearly 10–15% of the total stroke disease and affecting two million people worldwide, has a high mortality and disability rate and, thus, a major socioeconomic burden. However, there is no effective treatment available currently. The role of mesenchymal stem cells (MSCs) in regenerative medicine is well known owing to the simplicity of acquisition from various sources, low immunogenicity, adaptation to the autogenic and allogeneic systems, immunomodulation, self-recovery by secreting extracellular vesicles (EVs), regenerative repair, and antioxidative stress. MSC therapy provides an increasingly attractive therapeutic approach for ICH. Recently, the functions of MSCs such as neuroprotection, anti-inflammation, and improvement in synaptic plasticity have been widely researched in human and rodent models of ICH. MSC transplantation has been proven to improve ICH-induced injury, including the damage of nerve cells and oligodendrocytes, the activation of microglia and astrocytes, and the destruction of blood vessels. The improvement and recovery of neurological functions in rodent ICH models were demonstrated via the mechanisms such as neurogenesis, angiogenesis, anti-inflammation, anti-apoptosis, and synaptic plasticity. Here, we discuss the pathological mechanisms following ICH and the therapeutic mechanisms of MSC-based therapy to unravel new cues for future therapeutic strategies. Furthermore, some potential strategies for enhancing the therapeutic function of MSC transplantation have also been suggested.

Intranasal application of stem cells and their derivatives as a new hope in the treatment of cerebral hypoxia/ischemia: a review

Intranasal delivery of stem cells and conditioned medium to target the brain has attracted major interest in the field of regenerative medicine. In pre-clinical investigations during the last ten years, several research groups focused on this strategy to treat cerebral hypoxia/ischemia in neonates as well as adults. In this review, we discuss the curative potential of stem cells, stem cell derivatives, and their delivery route via intranasal application to the hypoxic/ischemic brain. After intranasal application, stem cells migrate from the nasal cavity to the injured area and exert therapeutic effects by reducing brain tissue loss, enhancing endogenous neurogenesis, and modulating cerebral inflammation that leads to functional improvements. However, application of this administration route for delivering stem cells and/or therapeutic substances to the damaged sites requires further optimization to translate the findings of animal experiments to clinical trials.

Stem cells in neonatal diseases: An overview

Preterm birth and its common complications are major causes of infant mortality and long-term morbidity. Despite great advances in understanding the pathogenesis of neonatal diseases and improvements in neonatal intensive care, effective therapies for the prevention or treatment for these conditions are still lacking. Stem cell (SC) therapy is rapidly emerging as a novel therapeutic tool for several diseases of the newborn with encouraging pre-clinical results that hold promise for translation to the bedside. The utility of different types of SCs in neonatal diseases is being explored. SC therapeutic efficacy is closely associated with its secretome-conditioned media and SC-derived extracellular vesicles, and a subsequent paracrine action in response to tissue injuries. In the current review, we summarize the pre-clinical and clinical studies of SCs and its secretome in diverse preterm and term birth-related diseases, thereby providing new insights for future therapies in neonatal medicine.

Optimization of an Intranasal Route for the Delivery of Human Neural Stem Cells to Treat a Neonatal Hypoxic-Ischemic Brain Injury Rat Model

OBJECTIVE

Stem cell administration via the intranasal route has shown promise as a new therapy for hypoxic-ischemic encephalopathy (HIE). In this study, we aimed to improve the intranasal delivery of stem cells to the brain.

METHODS

Human neural stem cells (hNSCs) were identified using immunofluorescence, morphological, and flow cytometry assays before transplantation, and cell migration capacity was examined using the transwell assay. Cerebral hypoxia-ischemia (HI) was induced in 7-day-old rats, followed by the intranasal transplantation of CM-Dil-labeled hNSCs. We examined various experimental conditions, including preconditioning hNSCs with hypoxia, catheter method, multiple low-dose transplantation, head position, cell appropriate concentration, and volume. Rats were sacrificed 1 or 3 days after the final intranasal administration, and parts of the nasal tissue and whole brain sections were analyzed under a fluorescence microscope.

RESULTS

The isolated hNSCs met the characteristics of neural stem cells. Hypoxia (5% O₂, 24 h) enhanced the surface expression of CXC chemokine receptor 4 (CXCR4) (9.21 ± 1.9% ~ 24.76 ± 2.24%, P < 0.01) on hNSCs and improved migration (toward stromal cell-derived factor 1 [SDF-1], 0.54 ± 0.11% ~ 8.65 ± 1.76%, P < 0.001; toward fetal bovine serum, 8.36 ± 0.81% ~ 21.74 ± 0.85%, P < 0.0001). Further improvement increased the number of surviving cell distribution with increased uniformity on the olfactory epithelium and allowed the cells to stay in the nasal cavity for at least 72 h, but they did not survive for longer than 48 h. Optimization of pre-transplantation conditions augmented the success rate of intranasally delivered cells to the brain (0-41.6%). We also tentatively identified that hNSCs crossed the olfactory epithelium into the tissue space below the lamina propria, with cerebrospinal fluid entering the cribriform plate into the subarachnoid space, and then migrated toward injured areas along the brain blood vessels.

CONCLUSION

This study offers some helpful advice and reference for addressing the problem of repeatability in the intranasal delivery of stem cells.

Neural stem cell delivery using brain-derived tissue-specific bioink for recovering from traumatic brain injury

Traumatic brain injury is one of the leading causes of accidental death and disability. The loss of parts in a severely injured brain induces edema, neuronal apoptosis, and neuroinflammation. Recently, stem cell transplantation demonstrated regenerative efficacy in an injured brain. However, the efficacy of current stem cell therapy needs improvement to resolve issues such as low survival of implanted stem cells and low efficacy of differentiation into respective cells. We developed brain-derived decellularized extracellular matrix (BdECM) bioink that is printable and has native brain-like stiffness. This study aimed to fabricate injured cavity-fit scaffold with BdECM bioink and assessed the utility of BdECM bioink for stem cell delivery to a traumatically injured brain. Our BdECM bioink had shear thinning property for three-dimensional (3D)-cell-printing and physical properties and fiber structures comparable to those of the native brain, which is important for tissue integration after implantation. The human neural stem cells (NSCs) (F3 cells) laden with BdECM bioink were found to be fully differentiated to neurons; the levels of markers for mature differentiated neurons were higher than those observed with collagen bioinkin vitro. Moreover, the BdECM bioink demonstrated potential in defect-fit carrier fabrication with 3D cell-printing, based on the rheological properties and shape fidelity of the material. As F3 cell-laden BdECM bioink was transplanted into the motor cortex of a rat brain, high efficacy of differentiation into mature neurons was observed in the transplanted NSCs; notably increased level of MAP2, a marker of neuronal differentiation, was observed. Furthermore, the transplanted-cell bioink suppressed reactive astrogliosis and microglial activation that may impede regeneration of the injured brain. The brain-specific material reported here is favorable for NSC differentiation and suppression of neuroinflammation and is expected to successfully support regeneration of a traumatically injured brain.

Involvement of various chemokine/chemokine receptor axes in trafficking and oriented locomotion of mesenchymal stem cells in multiple sclerosis patients

Multiple sclerosis (MS) is a specific type of chronic immune-mediated disease in which the immune responses are almost run against the central nervous system (CNS). Despite intensive research, a known treatment for MS disease yet to be introduced. Thus, the development of novel and safe medications needs to be considered for the disease management. Application of mesenchymal stem cells (MSCs) as an emerging approach was recruited forthe treatment of MS. MSCs have several sources and they can be derived from the umbilical cord, adipose tissue, and bone marrow. Chemokines are low molecular weight proteins that their functional activities are achieved by binding to the cell surface G protein-coupled receptors (GPCRs). Chemokine and chemokine receptors are of the most important and effective molecules in MSC trafficking within the different tissues in hemostatic and non-hemostatic circumstances. Chemokine/chemokine receptor axes play a pivotal role in the recruitment and oriented trafficking of immune cells both towards and within the CNS and it appears that chemokine/chemokine receptor signaling may be the most important leading mechanisms in the pathogenesis of MS. In this article, we hypothesized that the chemokine/chemokine receptor axes network have crucial and efficacious impacts on behavior of the MSCs, nonetheless, the exact responsibility of these axes on the targeted tropism of MSCs to the CNS of MS patients yet remained to be fully elucidated. Therefore, we reviewed the ability of MSCs to migrate and home into the CNS of MS patients via expression of various chemokine receptors in response to chemokines expressed by cells of CNS tissue, to provide a great source of knowledge.

Mitochondrial dysfunction in perinatal asphyxia: role in pathogenesis and potential therapeutic interventions

Perinatal asphyxia (PA)-induced brain injury may present as hypoxic-ischemic encephalopathy in the neonatal period, and long-term sequelae such as spastic motor deficits, intellectual disability, seizure disorders and learning disabilities. The brain injury is secondary to both the hypoxic-ischemic event and oxygenation-reperfusion following resuscitation. Following PA, a time-dependent progression of neuronal insult takes place in terms of transition of cell death from necrosis to apoptosis. This transition is the result of time-dependent progression of pathomechanisms which involve excitotoxicity, oxidative stress, and ultimately mitochondrial dysfunction in developing brain. More precisely mitochondrial respiration is suppressed and calcium signalling is dysregulated. Consequently, Bax-dependent mitochondrial permeabilization occurs leading to release of cytochrome c and activation of caspases leading to transition of cell death in developing brain. The therapeutic window lies within this transition process. At present, therapeutic hypothermia (TH) is the only clinical treatment available for treating moderate as well as severe asphyxia in new-born as it attenuates secondary loss of high-energy phosphates (ATP) (Solevåg et al. in Free Radic Biol Med 142:113-122, 2019; Gunn et al. in Pediatr Res 81:202-209, 2017), improving both short- and long-term outcomes. Mitoprotective therapies can offer a new avenue of intervention alone or in combination with therapeutic hypothermia for babies with birth asphyxia. This review will explore these mitochondrial pathways, and finally will summarize past and current efforts in targeting these pathways after PA, as a means of identifying new avenues of therapeutic intervention.

Delayed Double Treatment with Adult-Sourced Adipose-Derived Mesenchymal Stem Cells Increases Striatal Medium-Spiny Neuronal Number, Decreases Striatal Microglial Number, and Has No Subventricular Proliferative Effect, after Acute Neonatal Hypoxia-Ischemia in Male Rats

Perinatal hypoxia-ischemia (HI) is a major cause of striatal injury. Delayed post-treatment with adult-sourced bone marrow-derived mesenchymal stem cells (BMSCs) increased the absolute number of striatal medium-spiny neurons (MSNs) following perinatal HI-induced brain injury. Yet extraction of BMSCs is more invasive and difficult compared to extraction of adipose-derived mesenchymal stem cells (AD-MSCs), which are easily sourced from subcutaneous tissue. Adult-sourced AD-MSCs are also superior to BMSCs in the treatment of adult ischemic stroke. Therefore, we investigated whether delayed post-treatment with adult-sourced AD-MSCs increased the absolute number of striatal MSNs following perinatal HI-induced brain injury. This included investigation of the location of injected AD-MSCs within the brain, which were widespread in the dorsolateral subventricular zone (dlSVZ) at 1 day after their injection. Cells extracted from adult rat tissue were verified to be stem cells by their adherence to tissue culture plastic and their expression of specific ‘cluster of differentiation’ (CD) markers. They were verified to be AD-MSCs by their ability to differentiate into adipocytes and osteocytes in vitro. Postnatal day (PN) 7/8, male Sprague-Dawley rats were exposed to either HI right-sided brain injury or no HI injury. The HI rats were either untreated (HI + Diluent), single stem cell-treated (HI + MSCs×1), or double stem cell-treated (HI + MSCs×2). Control rats that were matched-for-weight and litter had no HI injury and were treated with diluent (Uninjured + Diluent). Treatment with AD-MSCs or diluent occurred either 7 days, or 7 and 9 days, after HI. There was a significant increase in the absolute number of striatal dopamine and cyclic AMP-regulated phosphoprotein (DARPP-32)-positive MSNs in the double stem cell-treated (HI + MSCs×2) group and the normal control group compared to the HI + Diluent group at PN21. We therefore investigated two potential mechanisms for this effect of double-treatment with AD-MSCs. Specifically, did AD-MSCs: (i) increase the proliferation of cells within the dlSVZ, and (ii) decrease the microglial response in the dlSVZ and striatum? It was found that a primary repair mechanism triggered by double treatment with AD-MSCs involved significantly decreased striatal inflammation. The results may lead to the development of clinically effective and less invasive stem cell therapies for neonatal HI brain injury.

Neuroprotective Potential of Bone Marrow-Derived Mesenchymal Stem Cells Following Chemotherapy

Cisplatin (CP) is extensively used in the medical oncology field for malignancy treatment, but its use is associated with neurological side effects that compromise the patients' quality of life. Cytotherapy is a new treatment strategy for tissue damage that has recently emerged. The use of bone marrow-derived mesenchymal stem cells (BM-MSCs) was investigated for its therapeutic potential against CP-induced chemobrain as well as various models of brain damage. This study was carried out to elucidate, for the first time, the role of the intravenous injection (IV) of BM-MSCs against CP-induced neurotoxicity in a rat model through investigation of the parameters of oxidative stress, inflammation, and apoptosis in brain tissue. A rat model of neurotoxicity was generated by intraperitoneal injection of 7.5 mg/kg CP while 2 × 10⁶ BM-MSCs was given by IV as a therapeutic dose. Injection of CP led to a significant rise in malondialdehyde and nitric oxide levels accompanied by a marked depletion of superoxide dismutase and reduced glutathione content in brain tissue in comparison to the normal control (NC) rats. Furthermore, a remarkable rise in the brain levels of inflammatory cytokines interleukin (IL)-1β and IL-6, together with the expression of apoptotic marker caspase-3, and the downregulation of the brain expression of proliferating marker Ki-67 in brain tissue were detected in the CP group compared to the NC group. Histopathological alterations were observed in the brain tissue of the CP group. BM-MSCs mitigated the biochemical and histopathological alterations induced by CP without affecting brain cell proliferation. BM-MSCs could be used as a promising neuroprotective agent against CP-induced neurotoxicity.

Mechanism of White Matter Injury and Promising Therapeutic Strategies of MSCs After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the most fatal subtype of stroke with high disability and high mortality rates, and there is no effective treatment. The predilection site of ICH is in the area of the basal ganglia and internal capsule (IC), where exist abundant white matter (WM) fiber tracts, such as the corticospinal tract (CST) in the IC. Proximal or distal white matter injury (WMI) caused by intracerebral parenchymal hemorrhage is closely associated with poor prognosis after ICH, especially motor and sensory dysfunction. The pathophysiological mechanisms involved in WMI are quite complex and still far from clear. In recent years, the neuroprotection and repairment capacity of mesenchymal stem cells (MSCs) has been widely investigated after ICH. MSCs exert many unique biological effects, including self-recovery by producing growth factors and cytokines, regenerative repair, immunomodulation, and neuroprotection against oxidative stress, providing a promising cellular therapeutic approach for the treatment of WMI. Taken together, our goal is to discuss the characteristics of WMI following ICH, including the mechanism and potential promising therapeutic targets of MSCs, aiming at providing new clues for future therapeutic strategies.

Neonatal Mesenchymal Stem Cell Treatment Improves Myelination Impaired by Global Perinatal Asphyxia in Rats

The effect of perinatal asphyxia (PA) on oligodendrocyte (OL), neuroinflammation, and cell viability was evaluated in telencephalon of rats at postnatal day (P)1, 7, and 14, a period characterized by a spur of neuronal networking, evaluating the effect of mesenchymal stem cell (MSCs)-treatment. The issue was investigated with a rat model of global PA, mimicking a clinical risk occurring under labor. PA was induced by immersing fetus-containing uterine horns into a water bath for 21 min (AS), using sibling-caesarean-delivered fetuses (CS) as controls. Two hours after delivery, AS and CS neonates were injected with either 5 μL of vehicle (10% plasma) or 5 × 10⁴ MSCs into the lateral ventricle. Samples were assayed for myelin-basic protein (MBP) levels; Olig-1/Olig-2 transcriptional factors; Gglial phenotype; neuroinflammation, and delayed cell death. The main effects were observed at P7, including: (i) A decrease of MBP-immunoreactivity in external capsule, corpus callosum, cingulum, but not in fimbriae of hippocampus; (ii) an increase of Olig-1-mRNA levels; (iii) an increase of IL-6-mRNA, but not in protein levels; (iv) an increase in cell death, including OLs; and (v) MSCs treatment prevented the effect of PA on myelination, OLs number, and cell death. The present findings show that PA induces regional- and developmental-dependent changes on myelination and OLs maturation. Neonatal MSCs treatment improves survival of mature OLs and myelination in telencephalic white matter.

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.

Nasal administration of mesenchymal stem cells reverses chemotherapy-induced peripheral neuropathy in mice

Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most frequently reported adverse effects of cancer treatment. CIPN often persists long after treatment completion and has detrimental effects on patient's quality of life. There are no efficacious FDA-approved drugs for CIPN. We recently demonstrated that nasal administration of mesenchymal stem cells (MSC) reverses the cognitive deficits induced by cisplatin in mice. Here we show that nasal administration of MSC after cisplatin- or paclitaxel treatment- completely reverses signs of established CIPN, including mechanical allodynia, spontaneous pain, and loss of intraepidermal nerve fibers (IENF) in the paw. The resolution of CIPN is associated with normalization of the cisplatin-induced decrease in mitochondrial bioenergetics in DRG neurons. Nasally administered MSC enter rapidly the meninges of the brain, spinal cord and peripheral lymph nodes to promote IL-10 production by macrophages. MSC-mediated resolution of mechanical allodynia, recovery of IENFs and restoration of DRG mitochondrial function critically depends on IL-10 production. MSC from IL-10 knockout animals are not capable of reversing the symptoms of CIPN. Moreover, WT MSC do not reverse CIPN in mice lacking IL-10 receptors on peripheral sensory neurons. In conclusion, only two nasal administrations of MSC fully reverse CIPN and the associated mitochondrial abnormalities via an IL-10 dependent pathway. Since MSC are already applied clinically, we propose that nasal MSC treatment could become a powerful treatment for the large group of patients suffering from neurotoxicities of cancer treatment.

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.

Microglia-Mediated Neurodegeneration in Perinatal Brain Injuries

Perinatal brain injuries, including encephalopathy related to fetal growth restriction, encephalopathy of prematurity, neonatal encephalopathy of the term neonate, and neonatal stroke, are a major cause of neurodevelopmental disorders. They trigger cellular and molecular cascades that lead in many cases to permanent motor, cognitive, and/or behavioral deficits. Damage includes neuronal degeneration, selective loss of subclasses of interneurons, blocked maturation of oligodendrocyte progenitor cells leading to dysmyelination, axonopathy and very likely synaptopathy, leading to impaired connectivity. The nature and severity of changes vary according to the type and severity of insult and maturation stage of the brain. Microglial activation has been demonstrated almost ubiquitously in perinatal brain injuries and these responses are key cell orchestrators of brain pathology but also attempts at repair. These divergent roles are facilitated by a diverse suite of transcriptional profiles and through a complex dialogue with other brain cell types. Adding to the complexity of understanding microglia and how to modulate them to protect the brain is that these cells have their own developmental stages, enabling them to be key participants in brain building. Of note, not only do microglia help build the brain and respond to brain injury, but they are a key cell in the transduction of systemic inflammation into neuroinflammation. Systemic inflammatory exposure is a key risk factor for poor neurodevelopmental outcomes in preterm born infants. Based on these observations, microglia appear as a key cell target for neuroprotection in perinatal brain injuries. Numerous strategies have been developed experimentally to modulate microglia and attenuate brain injury based on these strong supporting data and we will summarize these.

Intranasal mesenchymal stem cell therapy to boost myelination after encephalopathy of prematurity

Encephalopathy of prematurity (EoP) is a common cause of long-term neurodevelopmental morbidity in extreme preterm infants. Diffuse white matter injury (dWMI) is currently the most commonly observed form of EoP. Impaired maturation of oligodendrocytes (OLs) is the main underlying pathophysiological mechanism. No therapies are currently available to combat dWMI. Intranasal application of mesenchymal stem cells (MSCs) is a promising therapeutic option to boost neuroregeneration after injury. Here, we developed a double-hit dWMI mouse model and investigated the therapeutic potential of intranasal MSC therapy. Postnatal systemic inflammation and hypoxia-ischemia led to transient deficits in cortical myelination and OL maturation, functional deficits and neuroinflammation. Intranasal MSCs migrated dispersedly into the injured brain and potently improved myelination and functional outcome, dampened cerebral inflammationand rescued OL maturation after dWMI. Cocultures of MSCs with primary microglia or OLs show that MSCs secrete factors that directly promote OL maturation and dampen neuroinflammation. We show that MSCs adapt their secretome after ex vivo exposure to dWMI milieu and identified several factors including IGF1, EGF, LIF, and IL11 that potently boost OL maturation. Additionally, we showed that MSC-treated dWMI brains express different levels of these beneficial secreted factors. In conclusion, the combination of postnatal systemic inflammation and hypoxia-ischemia leads to a pattern of developmental brain abnormalities that mimics the clinical situation. Intranasal delivery of MSCs, that secrete several beneficial factors in situ, is a promising strategy to restore myelination after dWMI and subsequently improve the neurodevelopmental outcome of extreme preterm infants in the future.

Cell motility and migration as determinants of stem cell efficacy

BACKGROUND

Stem cells` (SC) functional heterogeneity and its poorly understood aetiology impedes clinical development of cell-based therapies in regenerative medicine and oncology. Recent studies suggest a strong correlation between the SC migration potential and their therapeutic efficacy in humans. Designating SC migration as a denominator of functional SC heterogeneity, we sought to identify highly migrating subpopulations within different SC classes and evaluate their therapeutic properties in comparison to the parental non-selected cells.

METHODS

We selected highly migrating subpopulations from mesenchymal and neural SC (sMSC and sNSC), characterized their features including but not limited to migratory potential, trophic factor release and transcriptomic signature. To assess lesion-targeted migration and therapeutic properties of isolated subpopulations in vivo, surgical transplantation and intranasal administration of MSCs in mouse models of glioblastoma and Alzheimer's disease respectively were performed.

FINDINGS

Comparison of parental non-selected cells with isolated subpopulations revealed superior motility and migratory potential of sMSC and sNSC in vitro. We identified podoplanin as a major regulator of migratory features of sMSC/sNSC. Podoplanin engineering improved oncovirolytic activity of virus-loaded NSC on distantly located glioblastoma cells. Finally, sMSC displayed more targeted migration to the tumour site in a mouse glioblastoma model and remarkably higher potency to reduce pathological hallmarks and memory deficits in transgenic Alzheimer's disease mice.

INTERPRETATION

Functional heterogeneity of SC is associated with their motility and migration potential which can serve as predictors of SC therapeutic efficacy.

FUNDING

This work was supported in part by the Robert Bosch Stiftung (Stuttgart, Germany) and by the IZEPHA grant.

hUCMSCs Mitigate LPS-Induced Trained Immunity in Ischemic Stroke

Innate immune memory is a part of the innate immune system that facilitates the elimination of pathogens. However, it may exacerbate neuropathology. In this study, we found that innate immune memory is detrimental in stroke, because it promotes the acute immune response and exacerbates ischemic infarcts. Mesenchymal stem cell therapy has been widely studied for its therapeutic potential in various diseases including stroke, but whether it diminishes innate immune memory has not been studied. Here, our study demonstrates that, after the activation of innate immune memory by lipopolysaccharide, mesenchymal stem cell therapy can diminish innate immune memory though down-regulation of H3 methylation and subsequently protect against stroke. Our results demonstrate that innate immune memory is detrimental in stroke, and we describe a novel potential therapeutic target involving the use of mesenchymal stem cells to treat stroke patients.

BM-MSC Transplantation Alleviates Intracerebral Hemorrhage-Induced Brain Injury, Promotes Astrocytes Vimentin Expression, and Enhances Astrocytes Antioxidation via the Cx43/Nrf2/HO-1 Axis

Intracerebral hemorrhage (ICH) is a particularly severe form of stroke, and reactive astrogliosis is a common response following injury to the central nervous system (CNS). Mesenchymal stem cells (MSCs) are reported to promote neurogenesis and alleviate the late side effects in injured brain regions. Gap junctions (Gjs) are abundant in the brain, where the richest connexin (Cx) is Cx43, most prominently expressed in astrocytes. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an essential transcription factor regulating antioxidant reactions. Here, we aimed to explore whether bone marrow MSCs (BM-MSCs) could alleviate brain injury and protect astrocytes from apoptosis, by regulating Cx43 and Nrf2. We validated the effect of BM-MSC transplantation in an ICH model in vivo and in vitro and detected changes using immunofluorescence, as well as protein and mRNA expression of glial fibrillary acidic protein (GFAP), vimentin (VIM), Cx43, Nrf2, and heme oxygenase-1 (HO-1). Our results showed that BM-MSC transplantation attenuated brain injury after ICH and upregulated VIM expression in vivo and in vitro. Additionally, Cx43 upregulation and Nrf2 nuclear translocation were observed in astrocytes cocultured with BM-MSC. Knockdown of Cx43 by siRNA restrained Nrf2 nuclear translocation. Cx43 and Nrf2 had a connection as determined by immunofluorescence and coimmunoprecipitation. We demonstrated that astrocytes undergo astroglial-mesenchymal phenotype switching and have anti-apoptotic abilities after BM-MSC transplantation, where Cx43 upregulation triggers Nrf2 nuclear translocation and promotes its phase II enzyme expression. The Cx43/Nrf2 interaction of astrocytes after BM-MSC transplantation may provide an important therapeutic target in the management of ICH.

Bone marrow mesenchymal stem cells transplantation alleviates brain injury after intracerebral hemorrhage in mice through the Hippo signaling pathway

Intracerebral hemorrhage (ICH) is a common acute nervous system disease with high mortality and severe disability. Mesenchymal stem cells (MSCs) have been reported to promote neurogenesis and to alleviate side effects in areas of brain injury areas. The Hippo pathway regulates diverse cellular processes, including cell survival, proliferation, differentiation, and organ size. Here, we found that transplantation of bone marrow MSCs (BM-MSCs) into the brains of mice could alleviate ICH-mediated injury and protect astrocytes from apoptosis by regulating mammalian sterile 20-like kinase (MST)1 and Yes-associated protein (YAP). Knocking down of MST1 by si-RNA triggered YAP nuclear translocation. We further demonstrated that astrocytes undergo astroglial-mesenchymal phenotype switching and become capable of proliferating after BM-MSC transplantation via the Hippo signaling pathway. Together, our identification of the Hippo pathway in mediating the beneficial effects of BM-MSCs may provide a novel therapeutic target in the treatment and management of ICH.

Bone-marrow derived mesenchymal stromal cells infusion in therapy refractory juvenile idiopathic arthritis patients

Objectives

To compare the total number of adverse events (AEs) before and after mesenchymal stromal cell (MSC) infusion in refractory JIA and to evaluate its effectiveness.

Methods

Single-centre Proof of Mechanism Phase Ib, open label intervention study in JIA patients previously failing all biologicals registered for their diagnosis. Six patients received 2 million/kg intravenous infusions of allogeneic bone-marrow derived MSC. In case of ACR-Ped30-response but subsequent loss of response one and maximal two repeated infusions are allowed.

Results

Six JIA patients with 9.2 years median disease duration, still active arthritis and damage were included. All had failed methotrexate, corticosteroids and median five different biologicals. MSC were administered twice in three patients. No acute infusion reactions were observed and a lower post-treatment than pre-treatment incidence in AEs was found. The one systemic onset JIA (sJIA) patient had again an evolving macrophage activation syndrome, 9 weeks after tocilizumab discontinuation and 7 weeks post-MSC infusion. Statistically significant decreases were found 8 weeks after one MSC infusion in VAS well-being (75–56), the JADAS-71 (24.5–11.0) and the cJADAS10 (18.0–10.6).

Conclusion

MSC infusions in six refractory JIA patients were safe, although in sJIA stopping the ‘failing’ biologic treatment carries a risk of a MAS flare, as the drug might still suppress the systemic features.

Trial registration

Trial register.nl, http://https://www.trialregister.nl, NTR4146.

Stem cell therapy for preventing neonatal diseases in the 21st century: Current understanding and challenges

Diseases of the preterm newborn such as bronchopulmonary dysplasia, necrotizing enterocolitis, cerebral palsy, and hypoxic-ischemic encephalopathy continue to be major causes of infant mortality and long-term morbidity. Effective therapies for the prevention or treatment for these conditions are still lacking as recent clinical trials have shown modest or no benefit. Stem cell therapy is rapidly emerging as a novel therapeutic tool for several neonatal diseases with encouraging pre-clinical results that hold promise for clinical translation. However, there are a number of unanswered questions and facets to the development of stem cell therapy as a clinical intervention. There is much work to be done to fully elucidate the mechanisms by which stem cell therapy is effective (e.g., anti-inflammatory versus pro-angiogenic), identifying important paracrine mediators, and determining the timing and type of therapy (e.g., cellular versus secretomes), as well as patient characteristics that are ideal. Importantly, the interaction between stem cell therapy and current, standard-of-care interventions is nearly completely unknown. In this review, we will focus predominantly on the use of mesenchymal stromal cells for neonatal diseases, highlighting the promises and challenges in clinical translation towards preventing neonatal diseases in the 21st century.

Recent Advances in Stem Cell Research in Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke with significant morbidity and mortality, and it often leads to poor clinical outcome. Although great efforts have been made toward animal and clinical studies, optimal therapy of SAH remains a challenge for scientists and clinicians. Increasing evidence suggests that stem-cell-based therapies may provide innovative approaches for treatment of SAH-related disability. In this review, we summarized the recent advances in stem cell research in SAH. Neuroregeneration after SAH could be conducted by the activation of endogenous neural stem cells (NSCs), transplantation of external stem cells, or reprogramming non-neuronal cell to neurons. The potential mechanism and signaling pathways, as well as the efficiency and safety of these stem cell treatments, were discussed in detail. Although lots of challenges remain for translating the laboratory findings and technologies into clinical therapies, these research studies provided the foundation and guidance for using different resources of stem cells as a brain repair strategy after SAH.

Bone Marrow Mesenchymal Stem Cells' Secretome Exerts Neuroprotective Effects in a Parkinson's Disease Rat Model

Parkinson's disease (PD) is characterized by a selective loss of dopamine (DA) neurons in the human midbrain causing motor dysfunctions. The exact mechanism behind dopaminergic cell death is still not completely understood and, so far, no cure or neuroprotective treatment for PD is available. Recent studies have brought attention to the variety of bioactive molecules produced by mesenchymal stem cells (MSCs), generally referred to as the secretome. Herein, we evaluated whether human MSCs-bone marrow derived (hBMSCs) secretome would be beneficial in a PD pre-clinical model, when compared directly with cell transplantation of hBMSCs alone. We used a 6-hydroxydpomanie (6-OHDA) rat PD model, and motor behavior was evaluated at different time points after treatments (1, 4, and 7 weeks). The impact of the treatments in the recovery of DA neurons was estimated by determining TH-positive neuronal densities in the substantia nigra and fibers in the striatum, respectively, at the end of the behavioral characterization. Furthermore, we determined the effect of the hBMSCs secretome on the neuronal survival of human neural progenitors in vitro, and characterized the secretome through proteomic-based approaches. This work demonstrates that the injection of hBMSCs secretome led to the rescue of DA neurons, when compared to transplantation of hBMSCs themselves, which can explain the recovery of secretome-injected animals' behavioral performance in the staircase test. Moreover, we observed that hBMSCs secretome induces higher levels of in vitro neuronal differentiation. Finally, the proteomic analysis revealed that hBMSCs secrete important exosome-related molecules, such as those related with the ubiquitin-proteasome and histone systems. Overall, this work provided important insights on the potential use of hBMSCs secretome as a therapeutic tool for PD, and further confirms the importance of the secreted molecules rather than the transplantation of hBMSCs for the observed positive effects. These could be likely through normalization of defective processes in PD, namely proteostasis or altered gene transcription, which lately can lead to neuroprotective effects.

Intranasal Delivery of Mesenchymal Stromal Cells Protects against Neonatal Hypoxic⁻Ischemic Brain Injury

Cerebral palsy (CP) is a permanent motor disorder that results from brain injury and neuroinflammation during the perinatal period. Mesenchymal stromal cells (MSCs) have been explored as a therapy in multiple adult neuroinflammatory conditions. Our study examined the therapeutic benefits of intranasal delivery of human umbilical cord tissue (UC) derived-MSCs in a rat model of neonatal hypoxic–ischemic (HI) brain injury. To do this, HI was performed on postnatal day 10 Sprague-Dawley rat pups via permanent ligation of the left carotid artery, followed by a hypoxic challenge of 8% oxygen for 90 min. A total of 200,000 UC-MSCs (10 million/kg) were administered intranasally 24 h post-HI. Motor control was assessed after seven days, followed by post-mortem. Analysis included brain immunohistochemistry, gene analysis and serum cytokine measurement. Neonatal HI resulted in brain injury with significant loss of neurons, particularly in the hippocampus. Intranasal administration of UC-MSCs significantly reduced the loss of brain tissue and increased the number of hippocampal neurons. HI significantly upregulated brain inflammation and expression of pro-inflammatory cytokines, while intranasal UC-MSCs significantly reduced markers of neuroinflammation. This study demonstrated that a clinically relevant dose (10 million/kg) of UC-MSCs was neuroprotective following HI by restoring neuronal cell numbers and reducing brain inflammation. Therefore, intranasal delivery of UC-MSCs may be an effective therapy for neonatal brain injury.

The Potential of Stem Cell Therapy to Repair White Matter Injury in Preterm Infants: Lessons Learned From Experimental Models

Diffuse white matter injury (dWMI) is a major cause of morbidity in the extremely preterm born infant leading to life-long neurological impairments, including deficits in cognitive, motor, sensory, psychological, and behavioral functioning. At present, no treatment options are clinically available to combat dWMI and therefore exploration of novel strategies is urgently needed. In recent years, the pathophysiology underlying dWMI has slowly started to be unraveled, pointing towards the disturbed maturation of oligodendrocytes (OLs) as a key mechanism. Immature OL precursor cells in the developing brain are believed to be highly sensitive to perinatal inflammation and cerebral oxygen fluctuations, leading to impaired OL differentiation and eventually myelination failure. OL lineage development under normal and pathological circumstances and the process of (re)myelination have been studied extensively over the years, often in the context of other adult and pediatric white matter pathologies such as stroke and multiple sclerosis (MS). Various studies have proposed stem cell-based therapeutic strategies to boost white matter regeneration as a potential strategy against a wide range of neurological diseases. In this review we will discuss experimental studies focusing on mesenchymal stem cell (MSC) therapy to reduce white matter injury (WMI) in multiple adult and neonatal neurological diseases. What lessons have been learned from these previous studies and how can we translate this knowledge to application of MSCs for the injured white matter in the preterm infant? A perspective on the current state of stem cell therapy will be given and we will discuss different important considerations of MSCs including cellular sources, timing of treatment and administration routes. Furthermore, we reflect on optimization strategies that could potentially reinforce stem cell therapy, including preconditioning and genetic engineering of stem cells or using cell-free stem cell products, to optimize cell-based strategy for vulnerable preterm infants in the near future.

Restoring In Vivo-Like Membrane Lipidomics Promotes Exosome Trophic Behavior from Human Placental Mesenchymal Stromal/Stem Cells

Human mesenchymal stem cells (hMSCs) are an effective tool in regenerative medicine notably for their intrinsic plentiful paracrine activity rather than differentiating properties. The hMSC secretome includes a wide spectrum of regulatory and trophic factors, encompassing several naked molecules as well as different kinds of extracellular vesicles (EVs). Among EVs, exosomes represent an intriguing population, able to shuttle proteins, transcription factors, and genetic materials, with a relevant role in cell-to-cell communication, modulating biological responses in recipient cells. In this context, the extracellular milieu can greatly impact the paracrine activity of stem cells, modifying their metabolism, and the dynamics of vesicle secretion. In the present study, we investigated the effects elicited on exosome patterning by tailored, ad hoc formulated lipid supplementation (Refeed^®) in MSCs derived from human fetal membranes (hFM-MSCs). Wound healing experiments revealed that stem cell exposure to exosomes obtained from Refeed^®-supplemented hFM-MSCs increased their migratory capability, although the amount of exosomes released after Refeed^® supplementation was lower than that yielded from non-supplemented cells. We found that such a decrease was mainly due to a different rate of exosomal exocytosis rather than to an effect of the lipid supplement on the endocytic pathway. Endoplasmic reticulum homeostasis was modified by supplementation, through the upregulation of PKR-like ER kinase (PERK) and inositol-requiring enzyme 1α (IRE1α). Increased expression of these proteins did not lead to stress-induced, unfolded protein response (UPR)-mediated apoptosis, nor did it affect phosphorylation of p38 kinase, suggesting that PERK and IRE1α overexpression was due to augmented metabolic activities mediated by optimization of a cellular feeding network afforded through lipid supplementation. In summary, these results demonstrate how tailored lipid supplementation can successfully modify the paracrine features in hFM-MSCs, impacting both intracellular vesicle trafficking and secreted exosome number and function.

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.

Mitochondrial transfer from mesenchymal stem cells to neural stem cells protects against the neurotoxic effects of cisplatin

Mesenchymal stem cells (MSCs) transfer healthy mitochondria to damaged acceptor cells via actin-based intercellular structures. In this study, we tested the hypothesis that MSCs transfer mitochondria to neural stem cells (NSCs) to protect NSCs against the neurotoxic effects of cisplatin treatment. Our results show that MSCs donate mitochondria to NSCs damaged in vitro by cisplatin. Transfer of healthy MSC-derived mitochondria decreases cisplatin-induced NSC death. Moreover, mitochondrial transfer from MSCs to NSCs reverses the cisplatin-induced decrease in mitochondrial membrane potential. Blocking the formation of actin-based intercellular structures inhibited the transfer of mitochondria to NSCs and abrogated the positive effects of MSCs on NSC survival. Conversely, overexpression of the mitochondrial motor protein Rho-GTPase 1 (Miro1) in MSCs increased mitochondrial transfer and further improved survival of cisplatin-treated NSCs.

In vivo, MSC administration prevented the loss of DCX+ neural progenitor cells in the subventricular zone and hippocampal dentate gyrus which occurs as a result of cisplatin treatment. We propose mitochondrial transfer as one of the mechanisms via which MSCs exert their therapeutic regenerative effects after cisplatin treatment.