Intranasal delivery of stem cells to the brain

Improvement of spatial learning and memory deficits by intranasal administration of human olfactory ecto-mesenchymal stem cells in an Alzheimer's disease rat model

Mesenchymal stem cells therapy provides a new perspective of therapeutic approaches in the treatment of neurodegenerative diseases. The present study aimed to investigate the effects of intranasally transplanted human "olfactory ecto-mesenchymal stem cells" (OE-MSCs) in Alzheimer's disease (AD) rats. In this study, we isolated OE-MSCs from human olfactory lamina propria and phenotypically characterized them using immunocytochemistry and flow cytometry. The undifferentiated OE-MSCs were transplanted either by intranasal (IN) or intrahippocampal (IH) injection to rat models of AD, which were induced by injecting amyloid-beta (Aβ) intrahippocampally. Behavioral, histological, and molecular assessments were performed after a three-month recovery period. Based on the results, intranasal administration of OE-MSCs significantly reduced Aβ accumulation and neuronal loss, improved learning and memory impairments, and increased levels of BDNF (brain-derived neurotrophic factor) and NMDAR (N-methyl-D-Aspartate receptors) in the AD rat model. These changes were more significant in animals who received OE-MSCs by intranasal injection. The results of this study suggest that OE-MSCs have the potential to enhance cognitive function in AD, possibly mediated by BDNF and the NMDA receptors.

Innovative drug delivery strategies to the CNS for the treatment of multiple sclerosis

Disorders of the central nervous system (CNS), such as multiple sclerosis (MS) represent a great emotional, financial and social burden. Despite intense efforts, great unmet medical needs remain in that field. MS is an autoimmune, chronic inflammatory demyelinating disease with no curative treatment up to date. The current therapies mostly act in the periphery and seek to modulate aberrant immune responses as well as slow down the progression of the disease. Some of these therapies are associated with adverse effects related partly to their administration route and show some limitations due to their rapid clearance and inability to reach the CNS. The scientific community have recently focused their research on developing MS therapies targeting different processes within the CNS. However, delivery of therapeutics to the CNS is mainly limited by the presence of the blood-brain barrier (BBB). Therefore, there is a pressing need to develop new drug delivery strategies that ensure CNS availability to capitalize on identified therapeutic targets. Several approaches have been developed to overcome or bypass the BBB and increase delivery of therapeutics to the CNS. Among these strategies, the use of alternative routes of administration, such as the nose-to-brain (N2B) pathway, offers a promising non-invasive option in the scope of MS, as it would allow a direct transport of the drugs from the nasal cavity to the brain. Moreover, the combination of bioactive molecules within nanocarriers bring forth new opportunities for MS therapies, allowing and/or increasing their transport to the CNS. Here we will review and discuss these alternative administration routes as well as the nanocarrier approaches useful to deliver drugs for MS.

CSF-derived extracellular vesicles from patients with Parkinson's disease induce symptoms and pathology

Parkinson's disease is characterized by the gradual appearance of intraneuronal inclusions that are primarily composed of misfolded α-synuclein protein, leading to cytotoxicity and neural death. Recent in vitro and in vivo studies suggest that misfolded α-synuclein may spread transcellularly in a prion-like manner, inducing pathological aggregates in healthy neurons, and is disseminated via secretion of extracellular vesicles. Accordingly, extracellular vesicles derived from brain lysates and CSF of patients with Parkinson's disease were shown to facilitate α-synuclein aggregation in healthy cells. Prompted by the hypothesis of Braak and colleagues that the olfactory bulb is one of the primary propagation sites for the initiation of Parkinson's disease, we sought to investigate the role of extracellular vesicles in the spread of α-synuclein and progression of Parkinson's disease through the olfactory bulb. Extracellular vesicles derived from the CSF of patients diagnosed with Parkinson's disease or with a non-synucleinopathy neurodegenerative disorder were administered intranasally to healthy mice, once daily over 4 days. Three months later, mice were subjected to motor and non-motor tests. Functional impairments were elucidated by histochemical analysis of midbrain structures relevant to Parkinson's disease pathology, 8 months after EVs treatment. Mice treated with extracellular vesicles from the patients with Parkinson's disease displayed multiple symptoms consistent with prodromal and clinical-phase Parkinson's disease such as hyposmia, motor behaviour impairments and high anxiety levels. Furthermore, their midbrains showed widespread α-synuclein aggregations, dopaminergic neurodegeneration, neuroinflammation and altered autophagy activity. Several unconventional pathologies were also observed, such as α-synuclein aggregations in the red nucleus, growth of premature grey hair and astrogliosis. Collectively, these data indicate that intranasally administered extracellular vesicles derived from the CSF of patients with Parkinson's disease can propagate α-synuclein aggregation in vivo and trigger Parkinson's disease-like symptoms and pathology in healthy mice.

Human umbilical cord-derived mesenchymal stem cells promote repair of neonatal brain injury caused by hypoxia/ischemia in rats

Administration of human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) is believed to be an effective method for treating neurodevelopmental disorders. In this study, we investigated the possibility of hUC-MSCs treatment of neonatal hypoxic/ischemic brain injury associated with maternal immune activation and the underlying mechanism. We established neonatal rat models of hypoxic/ischemic brain injury by exposing pregnant rats to lipopolysaccharide on day 16 or 17 of pregnancy. Rat offspring were intranasally administered hUC-MSCs on postnatal day 14. We found that polypyrimidine tract-binding protein-1 (PTBP-1) participated in the regulation of lipopolysaccharide-induced maternal immune activation, which led to neonatal hypoxic/ischemic brain injury. Intranasal delivery of hUC-MSCs inhibited PTBP-1 expression, alleviated neonatal brain injury-related inflammation, and regulated the number and function of glial fibrillary acidic protein-positive astrocytes, thereby promoting plastic regeneration of neurons and improving brain function. These findings suggest that hUC-MSCs can effectively promote the repair of neonatal hypoxic/ischemic brain injury related to maternal immune activation through inhibition of PTBP-1 expression and astrocyte activation.

Temozolomide hexadecyl ester targeted plga nanoparticles for drug-resistant glioblastoma therapy via intranasal administration

Introduction: Temozolomide (TMZ) is the first-line drug for glioblastoma (GBM), but it is limited in clinical use due to the drug resistance, poor brain targeting, and side effects. Temozolomide hexadecyl ester (TMZ16e), a TMZ derivative with high lipophilicity, membrane permeability, and high anti-glioma properties, has the potential to reverse drug resistance. In this study, anti-ephrin type-A receptor 3 (EphA3) modified TMZ16e loaded nanoparticles (NPs) were prepared for targeted GBM therapy via intranasal administration to deliver TMZ16e to the brain, treat drug-resistant glioma effectively, and reduce peripheral toxicity.

Methods: TMZ16e loaded NPs were prepared by emulsion solvent evaporation method followed by modified with anti-EphA3 (anti-EphA3-TMZ16e-NPs). In vitro evaluations were performed by an MTT assay and flow cytometry analysis. The orthotopic nude mice models were used to evaluate the anti-glioma effect in vivo. Additionally, we investigated the anti-drug resistant mechanism by western blot analysis.

Results: The particle size of the prepared NPs was less than 200 nm, and the zeta potential of TMZ16e-NPs and anti-EphA3-TMZ16e-NPs were -23.05 ± 1.48 mV and -28.65 ± 1.20mV, respectively, which is suitable for nasal delivery. In vitro studies have shown that anti-EphA3 modification increased the cellular uptake of nanoparticles in T98G cells. The cytotoxicity in the anti-EphA3-TMZ16e-NPs treated group was significantly higher than that of the TMZ16e-NPs, TMZ16e, and TMZ groups (p < 0.01), and the cell cycle was blocked. Western blotting analysis showed that the TMZ16e-loaded NPs were able to effectively downregulate the expression level of O6-methylguanine-deoxyribonucleic acid-methyltransferase (MGMT) protein in T98G cells and reverse drug resistance. In vivo studies showed that the median survival time of tumor-bearing nude mice in the anti-EphA3-TMZ16e-NPs group was extended to 41 days, which was 1.71-fold higher than that of the saline group and the TUNEL staining results of the brain tissue section indicated that the TMZ16e-loaded NPs could elevate apoptosis in T98G cells.

Conclusion: In conclusion, the TMZ16e-loaded NPs can be effectively delivered to the brain and targeted to gliomas, exhibiting better anti-glioma activity, indicating they possess great potential in the treatment of drug-resistant glioma.

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.

Diagnostic and Therapeutic Potential of Extracellular Vesicles

Extracellular vesicles (EVs) are naturally phospholipid enclosed nanovesicles released by many cells in the body. They are stable in circulation, have low immunogenicity, and act as carriers for functionally active biological molecules. They interact with target organs and bind to the receptors. Their target specificity is important to use EVs as noninvasive diagnostic and prognostic tools. EVs play a vital role in normal physiology and cellular communication. They are known to protect their cargo from degradation, which makes them important drug carriers for targeted drug delivery. Using EVs with markers and tracking their path in systemic circulation can be revolutionary in using them as diagnostic tools. We will discuss the scope of this in this paper. Although there are limitations in EVs isolation and storage, their high biocompatibility will fuel more innovations to overcome these challenges.

The Role of Extracellular Vesicles in the Developing Brain: Current Perspective and Promising Source of Biomarkers and Therapy for Perinatal Brain Injury

This comprehensive review focuses on our current understanding of the proposed physiological and pathological functions of extracellular vesicles (EVs) in the developing brain. Furthermore, since EVs have attracted great interest as potential novel cell-free therapeutics, we discuss advances in the knowledge of stem cell- and astrocyte-derived EVs in relation to their potential for protection and repair following perinatal brain injury. This review identified 13 peer-reviewed studies evaluating the efficacy of EVs in animal models of perinatal brain injury; 12/13 utilized mesenchymal stem cell-derived EVs (MSC-EVs) and 1/13 utilized astrocyte-derived EVs. Animal model, method of EV isolation and size, route, timing, and dose administered varied between studies. Notwithstanding, EV treatment either improved and/or preserved perinatal brain structures both macroscopically and microscopically. Additionally, EV treatment modulated inflammatory responses and improved brain function. Collectively this suggests EVs can ameliorate, or repair damage associated with perinatal brain injury. These findings warrant further investigation to identify the optimal cell numbers, source, and dosage regimens of EVs, including long-term effects on functional outcomes.

Nose-to-brain delivery: exploring newer domains for glioblastoma multiforme management

Glioblastoma multiforme (GBM) is the most common and aggressive form of the primary brain tumors in humans. The intricate pathophysiology, the development of resistance by tumor cells, and the inability of the drugs to effectively cross the blood-brain and blood-tumor barriers result in poor prognosis for GBM patients, with a median survival time of only 1 to 2 years. Nose-to-brain delivery offers an attractive, noninvasive strategy to enhance drug penetration or transport novel drug/gene carriers into the brain. Although the exact mechanism of intranasal delivery remains elusive, the olfactory and trigeminal nerve pathways have been found to play a vital role in circumventing the traditional barriers of brain targeting. This review discusses the intranasal pathway as a novel domain for delivering drugs and nanocarriers encapsulating drugs/genes, as well as stem cell carriers specifically to the glioma cells. Considering the fact that most of these studies are still in preclinical stage, translating such intranasal delivery strategies from bench to bedside would be a critical step for better management and prognosis of GBM. Graphical abstract.

From Transcriptome to Behavior: Intranasal Injection of Late Passage Human Olfactory Stem Cells Displays Potential in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, which is caused by the loss of dopaminergic (DAergic) neurons. Thus, cell replacement therapy (CRT) might be regarded as an alternative therapy to effectively treat motor functional defects in PD patients. Human olfactory ectomesenchymal stem cells (OE-MSCs) are a novel type of mesenchymal stem cells (MSCs) with a strong tendency to differentiate into DAergic neurons. However, there are various barriers to successful CRT including the proliferation capacity of stem cells at higher passage numbers as well as the route of stem cell delivery. In this regard, we aimed to explore the efficacy of late passage OE-MSC administration through the intranasal (IN) route in PD rat models. Herein, the proliferation capacity of OE-MSCs was compared at early and late passage numbers; then, the results were validated via RNA sequencing analysis. Subsequently, the efficacy of IN injection of late passage OE-MSC in PD models was evaluated. The results manifested the absence of noticeable differences in proliferation capacity and signaling pathways in OE-MSCs at early and late passage numbers. Moreover, it was found that the IN administration of OE-MSCs with a high passage number substantially increased the levels of DAergic markers and improved the motor function in rat models of PD. Overall, our findings suggested that OE-MSCs with a high passage number are a promising CRT candidate due to their fundamental potential to provide a large number of cells with an enormous proliferation capacity. Moreover, they exhibit the high efficiency of IN administration as a noninvasive route of late-passage OE-MSC delivery for CRT, particularly for PD.

Human umbilical cord mesenchymal stromal cells as an adjunct therapy with therapeutic hypothermia in a piglet model of perinatal asphyxia

BACKGROUND

With therapeutic hypothermia (HT) for neonatal encephalopathy, disability rates are reduced, but not all babies benefit. Pre-clinical rodent studies suggest mesenchymal stromal cells (MSCs) augment HT protection.

AIMS

The authors studied the efficacy of intravenous (IV) or intranasal (IN) human umbilical cord-derived MSCs (huMSCs) as adjunct therapy to HT in a piglet model.

METHODS

A total of 17 newborn piglets underwent transient cerebral hypoxia-ischemia (HI) and were then randomized to (i) HT at 33.5°C 1-13 h after HI (n = 7), (ii) HT+IV huMSCs (30 × 106 cells) at 24 h and 48 h after HI (n = 5) or (iii) HT+IN huMSCs (30 × 106 cells) at 24 h and 48 h after HI (n = 5). Phosphorus-31 and hydrogen-1 magnetic resonance spectroscopy (MRS) was performed at 30 h and 72 h and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells and oligodendrocytes quantified. In two further piglets, 30 × 106 IN PKH-labeled huMSCs were administered.

RESULTS

HI severity was similar between groups. Amplitude-integrated electroencephalogram (aEEG) recovery was more rapid for HT+IN huMSCs compared with HT from 25 h to 42 h and 49 h to 54 h (P ≤ 0.05). MRS phosphocreatine/inorganic phosphate was higher on day 2 in HT+IN huMSCs than HT (P = 0.035). Comparing HT+IN huMSCs with HT and HT+IV huMSCs, there were increased OLIG2 counts in hippocampus (P = 0.011 and 0.018, respectively), internal capsule (P = 0.013 and 0.037, respectively) and periventricular white matter (P = 0.15 for IN versus IV huMSCs). Reduced TUNEL-positive cells were seen in internal capsule with HT+IN huMSCs versus HT (P = 0.05). PKH-labeled huMSCs were detected in the brain 12 h after IN administration.

CONCLUSIONS

After global HI, compared with HT alone, the authors saw beneficial effects of HT+IN huMSCs administered at 24 h and 48 h (30 × 106 cells/kg total dose) based on more rapid aEEG recovery, improved 31P MRS brain energy metabolism and increased oligodendrocyte survival at 72 h.

Intranasal delivery of mitochondria for treatment of Parkinson's Disease model rats lesioned with 6-hydroxydopamine

The feasibility of delivering mitochondria intranasally so as to bypass the blood-brain barrier in treating Parkinson's disease (PD), was evaluated in unilaterally 6-OHDA-lesioned rats. Intranasal infusion of allogeneic mitochondria conjugated with Pep-1 (P-Mito) or unconjugated (Mito) was performed once a week on the ipsilateral sides of lesioned brains for three months. A significant improvement of rotational and locomotor behaviors in PD rats was observed in both mitochondrial groups, compared to sham or Pep-1-only groups. Dopaminergic (DA) neuron survival and recovery > 60% occurred in lesions of the substantia nigra (SN) and striatum in Mito and P-Mito rats. The treatment effect was stronger in the P-Mito group than the Mito group, but the difference was insignificant. This recovery was associated with restoration of mitochondrial function and attenuation of oxidative damage in lesioned SN. Notably, P-Mito suppressed plasma levels of inflammatory cytokines. Mitochondria penetrated the accessory olfactory bulb and doublecortin-positive neurons of the rostral migratory stream (RMS) on the ipsilateral sides of lesions and were expressed in striatal, but not SN DA neurons, of both cerebral hemispheres, evidently via commissural fibers. This study shows promise for intranasal delivery of mitochondria, confirming mitochondrial internalization and migration via RMS neurons in the olfactory bulb for PD therapy.

Advances in intranasal application of stem cells in the treatment of central nervous system diseases

Stem cells are characterized by their self-renewal and multipotency and have great potential in the therapy of various disorders. However, the blood-brain barrier (BBB) limits the application of stem cells in the therapy of neurological disorders, especially in a noninvasive way. It has been shown that small molecular substances, macromolecular proteins, and even stem cells can bypass the BBB and reach the brain parenchyma following intranasal administration. Here, we review the possible brain-entry routes of transnasal treatment, the cell types, and diseases involved in intranasal stem cell therapy, and discuss its advantages and disadvantages in the treatment of central nervous system diseases, to provide a reference for the application of intranasal stem cell therapy.

Intranasal Transplantation of Human Neural Stem Cells Ameliorates Alzheimer's Disease-Like Pathology in a Mouse Model

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by memory impairments, which has no effective therapy. Stem cell transplantation shows great potential in the therapy of various disease. However, the application of stem cell therapy in neurological disorders, especially the ones with a long-term disease course such as AD, is limited by the delivery approach due to the presence of the brain blood barrier. So far, the most commonly used delivery approach in the therapy of neurological disorders with stem cells in preclinical and clinical studies are intracranial injection and intrathecal injection, both of which are invasive. In the present study, we use repetitive intranasal delivery of human neural stem cells (hNSCs) to the brains of APP/PS1 transgenic mice to investigate the effect of hNSCs on the pathology of AD. The results indicate that the intranasally transplanted hNSCs survive and exhibit extensive migration and higher neuronal differentiation, with a relatively limited glial differentiation. A proportion of intranasally transplanted hNSCs differentiate to cholinergic neurons, which rescue cholinergic dysfunction in APP/PS1 mice. In addition, intranasal transplantation of hNSCs attenuates β-amyloid accumulation by upregulating the expression of β-amyloid degrading enzymes, insulin-degrading enzymes, and neprilysin. Moreover, intranasal transplantation of hNSCs ameliorates other AD-like pathology including neuroinflammation, cholinergic dysfunction, and pericytic and synaptic loss, while enhancing adult hippocampal neurogenesis, eventually rescuing the cognitive deficits of APP/PS1 transgenic mice. Thus, our findings highlight that intranasal transplantation of hNSCs benefits cognition through multiple mechanisms, and exhibit the great potential of intranasal administration of stem cells as a non-invasive therapeutic strategy for AD.

[Research progress of different types of stem cells in treatment of ischemic stroke]

Objective

To review the recent research progress of different types of stem cells in the treatment of ischemic stroke.

Methods

By searching the PubMed database, a systematic review had been carried out for the results of applying different types of stem cells in the treatment of ischemic stroke between 2000 and 2020.

Results

Stem cells can be transplanted via intracranial, intravascular, cerebrospinal fluid, and intranasal route in the treatment of ischemic stroke. Paracrine and cell replacement are the two major mechanisms of the therapy. The researches have mainly focused on utilization of neural stem cells, embryonic stem cells, and mesenchymal stem cells. Each has its own advantages and disadvantages in terms of capability of migration, survival rate, and safety. Certain stem cell therapies have completed phase one clinical trial.

Conclusion

Stem cells transplantation is feasible and has a great potential for the treatment of ischemic stroke, albeit that certain obstacles, including the selection of stem cells, transplantation strategy, migration ability, survival rate, still wait to be solved.

Intranasal Delivery: Effects on the Neuroimmune Axes and Treatment of Neuroinflammation

This review highlights the pre-clinical and clinical work performed to use intranasal delivery of various compounds from growth factors to stem cells to reduce neuroimmune interactions. We introduce the concept of intranasal (IN) delivery and the variations of this delivery method based on the model used (i.e., rodents, non-human primates, and humans). We summarize the literature available on IN delivery of growth factors, vitamins and metabolites, cytokines, immunosuppressants, exosomes, and lastly stem cells. We focus on the improvement of neuroimmune interactions, such as the activation of resident central nervous system (CNS) immune cells, expression or release of cytokines, and detrimental effects of signaling processes. We highlight common diseases that are linked to dysregulations in neuroimmune interactions, such as Alzheimer's disease, Parkinson's disease, stroke, multiple sclerosis, and traumatic brain injury.

Nanoparticlized System: Promising Approach for the Management of Alzheimer's Disease through Intranasal Delivery

Alzheimer's disease (AD) is a neurodegenerative brain problem and responsible for causing dementia in aged people. AD has become most common neurological disease in the elderly population worldwide and its treatment remains still challengeable. Therefore, there is a need of an efficient drug delivery system which can deliver the drug to the target site. Nasal drug delivery has been used since prehistoric times for the treatment of neurological disorders like Alzheimer's disease (AD). For delivering drug to the brain, blood brain barrier (BBB) is a major rate limiting factor for the drugs. The desired drug concentration could not be achieved through the conventional drug delivery system. Thus, nanocarrier based drug delivery systems are promising for delivering drug to brain. Nasal route is a most convenient for targeting drug to the brain. Several factors and mechanisms need to be considered for an effective delivery of drug to the brain particularly AD. Various nanoparticlized systems such as nanoparticles, liposomes, exosomes, phytosomes, nanoemulsion, nanosphere, etc. have been recognized as an effective drug delivery system for the management of AD. These nanocarriers have been proven with improved permeability as well as bioavailability of the anti-Alzheimer's drugs. Some novel drug delivery systems of anti-Alzheimer drugs are under investigation of different phase of clinical trials. Present article highlights on the nanotechnology based intranasal drug delivery system for the treatment of Alzheimer's disease. Furthermore, consequences of AD, transportation mechanism, clinical updates and recent patents on nose to brain delivery for AD have been discussed.

Particles Containing Cells as a Strategy to Promote Remyelination in Patients With Multiple Sclerosis

The repair of demyelinated lesions is a key objective in multiple sclerosis research. Remyelination fundamentally depends on oligodendrocyte progenitor cells (OPC) reaching the lesion; this is influenced by numerous factors including age, disease progression time, inflammatory activity, and the pool of OPCs available, whether they be NG2 cells or cells derived from neural stem cells. Administering OPCs has been proposed as a potential cell therapy; however, these cells can only be administered directly. This article discusses the potential administration of OPCs encapsulated within hydrogel particles composed of biocompatible biomaterials, via the nose-to-brain pathway. We also discuss conditions for the indication of this therapy, and such related issues as the influence on endogenous remyelination, migration of OPCs to demyelinated areas, and the immune response, given the autoimmune nature of multiple sclerosis. Chitosan and derivatives constitute the most promising biomaterial for this purpose, although these issues must be addressed. In conclusion, this line of research may yield an alternative to the remyelinating drugs currently being studied.

Neurorestoration Approach by Biomaterials in Ischemic Stroke

Ischemic stroke (IS) is the leading cause of disability in the western world, assuming a high socio-economic cost. One of the most used strategies in the last decade has been biomaterials, which have been initially used with a structural support function. They have been perfected, different compounds have been combined, and they have been used together with cell therapy or controlled release chemical compounds. This double function has driven them as potential candidates for the chronic treatment of IS. In fact, the most developed are in different phases of clinical trial. In this review, we will show the ischemic scenario and address the most important criteria to achieve a successful neuroreparation from the point of view of biomaterials. The spontaneous processes that are activated and how to enhance them is one of the keys that contribute to the success of the therapeutic approach. In addition, the different routes of administration and how they affect the design of biomaterials are analyzed. Future perspectives show where this broad scientific field is heading, which advances every day with the help of technology and advanced therapies.

Olfactory Ensheathing Cells: A Trojan Horse for Glioma Gene Therapy

BACKGROUND

The olfactory ensheathing cells (OECs) migrate from the peripheral nervous system to the central nervous system (CNS), a critical process for the development of the olfactory system and axonal extension after injury in neural regeneration. Because of their ability to migrate to the injury site and anti-inflammatory properties, OECs were tested against different neurological pathologies, but were never studied in the context of cancer. Here, we evaluated OEC tropism to gliomas and their potential as a "Trojan horse" to deliver therapeutic transgenes through the nasal pathway, their natural route to CNS.

METHODS

OECs were purified from the mouse olfactory bulb and engineered to express a fusion protein between cytosine deaminase and uracil phosphoribosyltransferase (CU), which convert the prodrug 5-fluorocytosine (5-FC) into cytotoxic metabolite 5-fluorouracil, leading to a bystander killing of tumor cells. These cells were injected into the nasal cavity of mice bearing glioblastoma tumors and OEC-mediated gene therapy was monitored by bioluminescence imaging and confirmed with survival and ex vivo histological analysis. All statistical tests were two-sided.

RESULTS

OECs migrated from the nasal pathway to the primary glioma site, tracked infiltrative glioma stemlike cells, and delivered therapeutic transgene, leading to a slower tumor growth and increased mice survival. At day 28, bioluminescence imaging revealed that mice treated with a single injection of OEC-expressing CU and 5-FC had tumor-associated photons (mean [SD]) of 1.08E + 08 [9.7E + 07] vs 4.1E + 08 [2.3E + 08] for control group (P < .001), with a median survival of 41 days vs 34 days, respectively (ratio = 0.8293, 95% confidence interval = 0.4323 to 1.226, P <  .001) (n = 9 mice per group).

CONCLUSIONS

We show for the first time that autologous transplantation of OECs can target and deliver therapeutic transgenes to brain tumors upon intranasal delivery, the natural route of OECs to the CNS, which could be extended to other types of cancer.

The role of non-coding RNAs in neuroprotection and angiogenesis following ischemic stroke

Stroke is the leading cause of death and physical disability worldwide. Non-coding RNAs (ncRNAs) are endogenous molecules that play key roles in the pathophysiology and retrieval processes following ischemic stroke. The potential of ncRNAs, especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in neuroprotection and angiogenesis highlights their potential as targets for therapeutic intervention. In this review, we document the miRNAs and lncRNAs that have been reported to exert regulatory actions in neuroprotective and angiogenic processes through different mechanisms involving their interaction with target coding genes. We believe that exploration of the expression profiles and the possible functions of ncRNAs during the recovery processes will help comprehension of the molecular mechanisms responsible for neuroprotection and angiogenesis, and may also contribute to find biomarkers and targets for future stroke intervention.

Intranasal Delivery of Bone Marrow Stromal Cells Preconditioned with Fasudil to Treat a Mouse Model of Parkinson's Disease

OBJECTIVE

Stem cell transplantation is a promising strategy with great potential to treat Parkinson's disease (PD). Nevertheless, improving the cell delivery route and optimising implanted cells are necessary to increase the therapeutic effect. Herein, we investigated whether intranasal delivery of bone marrow stromal cells (BMSCs) has beneficial effects in a PD mouse model and whether the therapeutic potential of BMSCs could be enhanced by preconditioning with fasudil.

METHODS

A PD mouse model was developed by intraperitoneally administering 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Mice were treated intranasally with phosphate buffered saline (PBS), BMSCs, or BMSCs preconditioned with fasudil. One month later, the effects of BMSC treatment were analysed.

RESULTS

Our study showed that fasudil could accelerate the proliferation of BMSCs and promote brain-derived neurotrophic factor (BDNF) secretion in vitro. Intranasally administered BMSCs were capable of surviving and migrating in the brain. Intranasal delivery of BMSCs preconditioned with fasudil significantly improved motor function and reduced dopaminergic neuron loss in substantia nigra; treatment with BMSCs and PBS resulted in similar outcomes. Preconditioning with fasudil inhibited the activation and aggregation of microglia, suppressed immune response, and reinforced BDNF secretion in MPTP-PD mice significantly more than treatment with BMSCs alone.

CONCLUSION

The present study demonstrates that intranasally administering BMSCs preconditioned with fasudil is a promising cell-based therapy for PD.

Human intracerebroventricular (ICV) injection of autologous, non-engineered, adipose-derived stromal vascular fraction (ADSVF) for neurodegenerative disorders: results of a 3-year phase 1 study of 113 injections in 31 patients

We have chosen to test the safety of human intracerebroventricular (ICV) brain injections of autologous non-genetically-modified adipose-derived stromal vascular fraction (ADSVF). In this IRB-approved trial, 24 patients received ICV ADSVF via an implanted reservoir between 5/22/14 and 5/22/17. Seven others were injected via their ventriculo-peritoneal shunts. Ten patients had Alzheimer's disease (AD), 6 had amyotrophic lateral sclerosis (ALS), 6 had progressive multiple sclerosis (MS-P), 6 had Parkinson's "Plus" (PD+), 1 had spinal cord injury, 1 had traumatic brain injury, and 1 had stroke. Median age was 74 (range 41-83). Injections were planned every 2-3 months. Thirty-one patients had 113 injections. Patients received SVF injection volumes of 3.5-20 cc (median:4 cc) containing 4.05 × 10⁵ to 6.2 × 10⁷ cells/cc, which contained an average of 8% hematopoietic and 7.5% adipose stem cells. Follow-up ranged from 0 to 36 months (median: 9.2 months). MRIs post injection(s) were unchanged, except for one AD patient whose hippocampal volume increased from < 5th percentile to 48th percentile (NeuroQuant^® volumetric MRI). Of the 10 AD patients, 8 were stable or improved in tests of cognition. Two showed improvement in P-tau and ß-amyloid levels. Of the 6 MS-P patients all are stable or improved. Four of 6 ALS patients died of disease progression. Twelve of 111 injections (11%) led to 1-4 days of transient meningismus, and mild temperature elevation, which resolved with acetaminophen and/or dexamethasone. Two (1.8% of injections) required hospitalization for these symptoms. One patient (0.9% of injections) had his reservoir removed and later replaced for presumed infection. In this Phase 1 safety trial, ADSVF was safely injected into the human brain ventricular system in patients with no other treatment options. Secondary endpoints of clinical improvement or stability were particularly promising in the AD and MS-P groups. These results will be submitted for a Phase 2 FDA-approved trial.

Intracerebroventricular Administration of Neural Stem Cells after Cardiac Arrest

Cardiac arrest (CA) is a serious disease with high rates of mortality and disability worldwide. Currently, neither pharmacological intervention nor therapeutic hypothermia can reverse the neural injury caused by CA. Neural stem cell therapy is a promising treatment for brain injury. We investigated the effects of the intracerebroventricular (ICV) administration of human neural stem cells (hNSCs) on global brain ischemia injury after CA. Twelve Long-Evans rats (4 Male and 8 female) subjected to 8-min asphyxia-CA were randomly assigned to hNSC treatment (n=7) or control group (n=5). The hNSCs were slowly infused into the left lateral ventricular 3 hours after resuscitation. An additional two rats subjected to 8-min asphyxia-CA were euthanized at 4 weeks after resuscitation to confirm the survival and function of transplanted PKH26 pre-labeled hNSCs by brain slides and whole cell patch clamp. Electrophysiological monitoring, quantitative EEG value (qEEG-IQ) and neurological deficit score (NDS) were used to evaluate the functional outcome. Immunofluorescence staining was used to investigate the survival of neurons and track migration of hNSCs. There was a significant improvement on the behavior tests evaluated as a subgroup of NDS (p <; 0.05) in the NSCs group than the control group. Immunofluorescent co-staining of PKH26 and NeuN verified the neuronal differentiation from transplanted PKH26+ hNSCs in the hippocampus CA1 and cortex 4 weeks after CA. The whole-cell patch clamp technique confirmed the spontaneous firing activity that was recorded in cell-attached mode from the functional mature neurons derived from transplanted cells. Transplanted hNSCs via ICV administration markedly improved neurologic outcomes after CA. Further studies are needed to elucidate the neuroprotective mechanism.

Golden Exosomes Selectively Target Brain Pathologies in Neurodegenerative and Neurodevelopmental Disorders

Exosomes, nanovesicles that are secreted by different cell types, enable intercellular communication at local or distant sites. Alhough they have been found to cross the blood brain barrier, their migration and homing abilities within the brain remain unstudied. We have recently developed a method for longitudinal and quantitative in vivo neuroimaging of exosomes based on the superior visualization abilities of classical X-ray computed tomography (CT), combined with gold nanoparticles as labeling agents. Here, we used this technique to track the migration and homing patterns of intranasally administrated exosomes derived from bone marrow mesenchymal stem cells (MSC-exo) in different brain pathologies, including stroke, autism, Parkinson's disease, and Alzheimer's disease. We found that MSC-exo specifically targeted and accumulated in pathologically relevant murine models brains regions up to 96 h post administration, while in healthy controls they showed a diffuse migration pattern and clearance by 24 h. The neuro-inflammatory signal in pathological brains was highly correlated with MSC-exo accumulation, suggesting that the homing mechanism is inflammatory-driven. In addition, MSC-exo were selectively uptaken by neuronal cells, but not glial cells, in the pathological regions. Taken together, these findings can significantly promote the application of exosomes for therapy and targeted drug delivery in various brain pathologies.

Deciduous DPSCs Ameliorate MPTP-Mediated Neurotoxicity, Sensorimotor Coordination and Olfactory Function in Parkinsonian Mice

Parkinson's disease (PD) is a neurodegenerative disorder defined by progressive deterioration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Dental pulp stem cells (DPSCs) have been proposed to replace the degenerated dopaminergic neurons due to its inherent neurogenic and regenerative potential. However, the effective delivery and homing of DPSCs within the lesioned brain has been one of the many obstacles faced in cell-based therapy of neurodegenerative disorders. We hypothesized that DPSCs, delivered intranasally, could circumvent these challenges. In the present study, we investigated the therapeutic efficacy of intranasally administered DPSCs in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Human deciduous DPSCs were cultured, pre-labelled with PKH 26, and intranasally delivered into PD mice following MPTP treatment. Behavioural analyses were performed to measure olfactory function and sensorimotor coordination, while tyrosine hydroxylase (TH) immunofluorescence was used to evaluate MPTP neurotoxicity in SNpc neurons. Upon intranasal delivery, degenerated TH-positive neurons were ameliorated, while deterioration in behavioural performances was significantly enhanced. Thus, the intranasal approach enriched cell delivery to the brain, optimizing its therapeutic potential through its efficacious delivery and protection against dopaminergic neuron degeneration.

Application of olfactory ensheathing cells in clinical treatment of spinal cord injury: meta-analysis and prospect

Background:

A number of clinical trials of olfactory ensheathing cells (OECs) for the treatment of chronic spinal cord injury (SCI) have been carried out all over the world. However, their safety and efficacy have not been basically evaluated. Moreover, there are no uniform standards laid out for the use of optimal source, transplantation method and the dosage of OECs.

Objective:

This study evaluated the source, dose, and route of transplantation of OECs for the treatment of chronic SCI.

Methods:

PubMed, Cochrane Library, EMBASE, CNKI, and Wanfang Data were searched for the clinical studies of OECs in the treatment of chronic SCI on July 2018.

Results:

A total of 30 articles on OECs transplantation for chronic SCI were selected for comprehensive evaluation of OECs sources, doses, and transplantation methods. The efficacy of OECs in the treatment of chronic SCI was evaluated using Review Manager 5.3.

Conclusion:

Fetal OECs are the primary source of cells for the treatment of chronic SCI in OECs, with standardized cell-culture and quality-control processes. Fetal OECs can significantly improve the neurological function of patients with chronic SCI. It is an ideal cell therapy for neurorestoration. However to explore more precise and minimally invasive treatment options are required in the future.

Therapy of breast cancer brain metastases: challenges, emerging treatments and perspectives

Brain metastases are the most common central nervous system tumors in adults, and incidence of brain metastases is increasing due to both improved diagnostic techniques (e.g. magnetic resonance imaging) and increased cancer patient survival through advanced systemic treatments. Outcomes of patients remain disappointing and treatment options are limited, usually involving multimodality approaches. Brain metastases represent an unmet medical need in solid tumor care, especially in breast cancer, where brain metastases are frequent and result in impaired quality of life and death. Challenges in the management of brain metastases have been highlighted in this review. Innovative research and treatment strategies, including prevention approaches and emerging systemic treatment options for brain metastases of breast cancer, are further discussed.

The Route by Which Intranasally Delivered Stem Cells Enter the Central Nervous System

Intranasal administration is a promising route of delivery of stem cells to the central nervous system (CNS). Reports on this mode of stem cell delivery have not yet focused on the route across the cribriform plate by which cells move from the nasal cavity into the CNS. In the current experiments, human mesenchymal stem cells (MSCs) were isolated from Wharton’s jelly of umbilical cords and were labeled with extremely bright quantum dots (QDs) in order to track the cells efficiently. At 2 h after intranasal delivery in immunodeficient mice, the labeled cells were found under the olfactory epithelium, crossing the cribriform plate adjacent to the fila olfactoria, and associated with the meninges of the olfactory bulb. At all times, the cells were separate from actual nerve tracts; this location is consistent with them being in the subarachnoid space (SAS) and its extensions through the cribriform plate into the nasal mucosa. In their location under the olfactory epithelium, they appear to be within an expansion of a potential space adjacent to the turbinate bone periosteum. Therefore, intranasally administered stem cells appear to cross the olfactory epithelium, enter a space adjacent to the periosteum of the turbinate bones, and then enter the SAS via its extensions adjacent to the fila olfactoria as they cross the cribriform plate. These observations should enhance understanding of the mode by which stem cells can reach the CNS from the nasal cavity and may guide future experiments on making intranasal delivery of stem cells efficient and reproducible.

Intranasal Delivery of Umbilical Cord-Derived Mesenchymal Stem Cells Preserves Myelination in Perinatal Brain Damage

Preterm white matter injury (WMI) is an important cause for long-term disability. Stem cell transplantation has been proposed as a novel therapeutic approach. However, intracerebral transplantation is not feasible for clinical purpose in newborns. Intranasal delivery of cells to the brain might be a promising, noninvasive therapeutic approach to restore the damaged brain. Therefore, our goal is to study the remyelinating potential of human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) after intranasal delivery. Wistar rat pups, previously brain-damaged by a combined hypoxic-ischemic and inflammatory insult, received hWJ-MSC (150,000 cells in 3 μL) that were intranasally delivered twice to each nostril (600,000 cells total). WMI was assessed by immunohistochemistry and western blot for myelination, astrogliosis, and microgliosis. The expression of preoligodendrocyte markers, and neurotrophic factors, was analyzed by real-time polymerase chain reaction. Animals treated with intranasally delivered hWJ-MSC showed increased myelination and decreased gliosis compared to untreated animals. hWJ-MSC may, therefore, modulate the activation of microglia and astrocytes, resulting in a change of the brain microenvironment, which facilitates the maturation of oligodendrocyte lineage cells. This is the first study to show that intranasal delivery of hWJ-MSC in rats prevented hypomyelination and microgliosis in a model of WMI in the premature rat brain. Further studies should address the dose and frequency of administration.

Emerging Roles of microRNAs in Ischemic Stroke: As Possible Therapeutic Agents

Stroke is one of the leading causes of death and physical disability worldwide. The consequences of stroke injuries are profound and persistent, causing in considerable burden to both the individual patient and society. Current treatments for ischemic stroke injuries have proved inadequate, partly owing to an incomplete understanding of the cellular and molecular changes that occur following ischemic stroke. MicroRNAs (miRNA) are endogenously expressed RNA molecules that function to inhibit mRNA translation and have key roles in the pathophysiological processes contributing to ischemic stroke injuries. Potential therapeutic areas to compensate these pathogenic processes include promoting angiogenesis, neurogenesis and neuroprotection. Several miRNAs, and their target genes, are recognized to be involved in these recoveries and repair mechanisms. The capacity of miRNAs to simultaneously regulate several target genes underlies their unique importance in ischemic stroke therapeutics. In this Review, we focus on the role of miRNAs as potential diagnostic and prognostic biomarkers, as well as promising therapeutic agents in cerebral ischemic stroke.

Drug delivery in overcoming the blood-brain barrier: role of nasal mucosal grafting

The blood-brain barrier (BBB) plays a fundamental role in protecting and maintaining the homeostasis of the brain. For this reason, drug delivery to the brain is much more difficult than that to other compartments of the body. In order to bypass or cross the BBB, many strategies have been developed: invasive techniques, such as temporary disruption of the BBB or direct intraventricular and intracerebral administration of the drug, as well as noninvasive techniques. Preliminary results, reported in the large number of studies on the potential strategies for brain delivery, are encouraging, but it is far too early to draw any conclusion about the actual use of these therapeutic approaches. Among the most recent, but still pioneering, approaches related to the nasal mucosa properties, the permeabilization of the BBB via nasal mucosal engrafting can offer new potential opportunities. It should be emphasized that this surgical procedure is quite invasive, but the implication for patient outcome needs to be compared to the gold standard of direct intracranial injection, and evaluated whilst keeping in mind that central nervous system diseases and lysosomal storage diseases are chronic and severely debilitating and that up to now no therapy seems to be completely successful.

Effect of intranasal stem cell administration on the nigrostriatal system in a mouse model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease worldwide. It affects the locomotor system, leading to a final severe disability through degeneration of dopaminergic neurons. Despite several therapeutic approaches used, no treatment has been proven to be effective; however, cell therapy may be a promising therapeutic method. In addition, the use of the intranasal (IN) route has been advocated for delivering various therapies to the brain. In the present study, the IN route was used for administration of mesenchymal stem cells (MSCs) in a mouse model of PD, with the aim to evaluate IN delivery as an alternative route for cell based therapy administration in PD. The PD model was developed in C57BL/6 mice using intraperitoneal rotenone administration for 60 consecutive days. MSCs were isolated from the mononuclear cell fraction of pooled bone marrow from C57BL/6 mice and incubated with micrometer-sized iron oxide (MPIO) particles. For IN administration, we used a 20 µl of 5×10⁵ cell suspension. Neurobehavioral assessment of the mice was performed, and after sacrifice, brain sections were stained with Prussian blue to detect the MPIO-labeled MSCs. In addition, immunohistochemical evaluation was conducted to detect tyrosine hydroxylase (TH) antibodies in the corpus striatum and dopaminergic neurons in the substantia nigra pars compacta (SNpc). The neurobehavioral assessment revealed progressive deterioration in the locomotor functions of the rotenone group, which was improved following MSC administration. Histopathological evaluation of brain sections in the rotenone+MSC group revealed successful delivery of MSCs, evidenced by positive Prussian blue staining. Furthermore, rotenone treatment led to significant decrease in dopaminergic neuron number in SNpc, as well as similar decrease in the corpus striatum fiber density. By contrast, in animals receiving IN administration of MSCs, the degeneration caused by rotenone treatment was significantly counteracted. In conclusion, the present study validated that IN delivery of MSCs may be a potential safe, easy and cheap alternative route for stem cell treatment in neurodegenerative disorders.

Perillyl Alcohol and Its Drug-Conjugated Derivatives as Potential Novel Methods of Treating Brain Metastases

Metastasis to the central nervous system remains difficult to treat, and such patients are faced with a dismal prognosis. The blood-brain barrier (BBB), despite being partially compromised within malignant lesions in the brain, still retains much of its barrier function and prevents most chemotherapeutic agents from effectively reaching the tumor cells. Here, we review some of the recent developments aimed at overcoming this obstacle in order to more effectively deliver chemotherapeutic agents to the intracranial tumor site. These advances include intranasal delivery to achieve direct nose-to-brain transport of anticancer agents and covalent modification of existing drugs to support enhanced penetration of the BBB. In both of these areas, use of the natural product perillyl alcohol, a monoterpene with anticancer properties, contributed to promising new results, which will be discussed here.

Biodistribution of in vitro-derived microglia applied intranasally and intravenously to mice: effects of aging

BACKGROUND AIMS

The age of both the donor and the recipient has a potential influence on the efficacy of various cell therapies, but the underlying mechanisms are still being charted. We studied the effect of donor and recipient age in the context of microglia migration.

METHODS

Microglia were in vitro--differentiated from bone marrow of young (3 months) and aged (12 months) mice and transplanted into young (∼ 3 months) and aged (∼ 17 months) C57BL/6 mice (n = 25) through intravenous and intranasal application routes. Recipients were not immune-suppressed or irradiated. Transplanted microglia were tracked through the use of a sex-mismatched setup or histologically with the use of cells from enhanced green fluorescent protein enhanced green fluorescent protein transgenic mice.

RESULTS

No acute rejections or transplant-associated toxicity was observed. After 10 days, both intravenously and intranasally transplanted cells were detected in the brain. Transplanted cells were also found in the blood and the lymph system. The applied cells were also tracked in lungs and kidney but only after intravenous injection subjected to a "pulmonary first-pass effect." After 28 days, intravenously delivered cells were also found in the bone marrow and other organs, especially in aged recipients. Whereas in young recipients the transplanted microglia did not appear to persist, in aged brains the transplanted cells could still be identified up to 28 days after transplantation. However, when cells from aged donors were used, no signals of transplanted cells could be detected in the recipients.

CONCLUSIONS

This study establishes proof of principle that in vitro--derived microglia from young but not from aged donors, intravenously or intranasally transplanted, migrate to the brain in young and aged recipients.

Intranasal delivery: circumventing the iron curtain to treat neurological disorders

INTRODUCTION

The blood-brain barrier (BBB) is like an iron curtain that prevents exogenous substances, including most drugs, from entering the CNS. Intranasal delivery has been demonstrated to circumvent the BBB due to the special anatomy of the olfactory and trigeminal neural pathways that connect the nasal mucosa with the brain and the perivascular pathway within the CNS. In the last two decades, the concepts, mechanisms and pathways of intranasal delivery to the CNS have led to great success both in preclinical and clinical studies. More researchers have translated results from bench to bedside, and a number of publications have reported the clinical application of intranasal delivery.

AREAS COVERED

This review summarizes results from recent clinical trials utilizing intranasal delivery of therapeutics to explore its pharmacokinetics and application to treating neurological disorders. Moreover, existing problems with the methods and possible solutions have also been discussed. The promising results from clinical trials have demonstrated that intranasal delivery provides an extraordinary approach for circumventing the BBB. Many drugs, including high-molecular-weight molecules, could potentially improve the treatment of neurological disorders via intranasal administration.

EXPERT OPINION

Intranasal delivery is a novel method with great potential for delivering and targeting therapeutics to the CNS to treat neurological disorders.

Intranasal delivery of hypoxia-preconditioned bone marrow-derived mesenchymal stem cells enhanced regenerative effects after intracerebral hemorrhagic stroke in mice

Intracerebral hemorrhagic stroke (ICH) causes high mortality and morbidity with very limited treatment options. Cell-based therapy has emerged as a novel approach to replace damaged brain tissues and promote regenerative processes. In this study we tested the hypothesis that intranasally delivered hypoxia-preconditioned BMSCs could reach the brain, promote tissue repair and improve functional recovery after ICH. Hemorrhagic stroke was induced in adult C57/B6 mice by injection of collagenase IV into the striatum. Animals were randomly divided into three groups: sham group, intranasal BMSC treatment group, and vehicle treatment group. BMSCs were pre-treated with hypoxic preconditioning (HP) and pre-labeled with Hoechst before transplantation. Behavior tests, including the mNSS score, rotarod test, adhesive removal test, and locomotor function evaluation were performed at varying days, up to 21days, after ICH to evaluate the therapeutic effects of BMSC transplantation. Western blots and immunohistochemistry were performed to analyze the neurotrophic effects. Intranasally delivered HP-BMSCs were identified in peri-injury regions. NeuN+/BrdU+ co-labeled cells were markedly increased around the hematoma region, and growth factors, including BDNF, GDNF, and VEGF were significantly upregulated in the ICH brain after BMSC treatment. The BMSC treatment group showed significant improvement in behavioral performance compared with the vehicle group. Our data also showed that intranasally delivered HP-BMSCs migrated to peri-injury regions and provided growth factors to increase neurogenesis after ICH. We conclude that intranasal administration of BMSC is an effective treatment for ICH, and that it enhanced neuroregenerative effects and promoted neurological functional recovery after ICH. Overall, the investigation supports the potential therapeutic strategy for BMSC transplantation therapy against hemorrhagic stroke.

Intranasal Delivery of Bone Marrow Mesenchymal Stem Cells Improved Neurovascular Regeneration and Rescued Neuropsychiatric Deficits after Neonatal Stroke in Rats

Neonatal stroke is a major cause of mortality and long-term morbidity in infants and children. Currently, very limited therapeutic strategies are available to protect the developing brain against ischemic damage and promote brain repairs for pediatric patients. Moreover, children who experienced neonatal stroke often have developmental social behavior problems. Cellular therapy using bone marrow mesenchymal stem cells (BMSCs) has emerged as a regenerative therapy after stroke. In the present investigation, neonatal stroke of postnatal day 7 (P7) rat pups was treated with noninvasive and brain-specific intranasal delivery of BMSCs at 6 h and 3 days after stroke (1 × 106cells/animal). Prior to transplantation, BMSCs were subjected to hypoxic preconditioning to enhance their tolerance and regenerative properties. The effects on regenerative activities and stroke-induced sensorimotor and social behavioral deficits were specifically examined at P24 of juvenile age. The BMSC treatment significantly reduced infarct size and blood-brain barrier disruption, promoted angiogenesis, neurogenesis, neurovascular repair, and improved local cerebral blood flow in the ischemic cortex. BMSC-treated rats showed better sensorimotor and olfactory functional recovery than saline-treated animals, measured by the adhesive removal test and buried food finding test. In social behavioral tests, we observed functional and social behavioral deficits in P24 rats subjected to stroke at P7, while the BMSC treatment significantly improved the performance of stroke animals. Overall, intranasal BMSC transplantation after neonatal stroke shows neuroprotection and great potential as a regenerative therapy to enhance neurovascular regeneration and improve functional recovery observed at the juvenile stage of development.

Opportunities and challenges: stem cell-based therapy for the treatment of ischemic stroke

Stem cell-based therapy for ischemic stroke has been widely explored in animal models and provides strong evidence of benefits. In this review, we summarize the types of stem cells, various delivery routes, and tracking tools for stem cell therapy of ischemic stroke. MSCs, EPCs, and NSCs are the most explored cell types for ischemic stroke treatment. Although the mechanisms of stem cell-based therapies are not fully understood, the most possible functions of the transplanted cells are releasing growth factors and regulating microenvironment through paracrine mechanism. Clinical application of stem cell-based therapy is still in its infancy. The next decade of stem cell research in stroke field needs to focus on combining different stem cells and different imaging modalities to fully explore the potential of this therapeutic avenue: from bench to bedside and vice versa.

Intranasal delivery of stem cells as therapy for central nervous system disease

Stem cells, upon entering the CNS, can preferentially migrate into disease foci, where they exert therapeutic effects that compensate for lost tissue, reconstructing damaged neuronal circuitry and establishing in the brain a new microenvironment suitable for cell survival. However, the route of stem cell delivery into the CNS remains a challenge: with systemic administration (e.g., intravenous injection), a fraction of cells may be trapped in other organs than the CNS, while direct CNS injections, e.g., intracerebroventricular or transcranial, are invasive. Intranasal (i.n.) delivery of stem cells, in contrast, can effectively bypass the blood-brain barrier, rapidly enter the CNS, and minimize systemic distribution. I.n. delivery of stem cells may therefore be a safe and non-invasive way of targeting the CNS and would thus be a promising therapeutic option for CNS disease. In this review we discuss the i.n. route for stem cell delivery into the CNS, and the perspectives of i.n. stem cell-based therapy in CNS disease.

Adoptive transfer of cytokine-induced immunomodulatory adult microglia attenuates experimental autoimmune encephalomyelitis in DBA/1 mice

Microglia are resident antigen-presenting cells in the central nervous system (CNS) that either suppress or promote disease depending on their activation phenotype and the microenvironment. Multiple sclerosis (MS) is a chronic inflammatory disease causing demyelination and nerve loss in the CNS, and experimental autoimmune encephalomyelitis (EAE) is an animal model of MS that is widely used to investigate pathogenic mechanisms and therapeutic effects. We isolated and cultured microglia from adult mouse brains and exposed them to specific combinations of stimulatory molecules and cytokines, the combination of IL-4, IL-10, and TGF-β yielding the optimal regime for induction of an immunosuppressive phenotype (M2). M2 microglia were characterized by decreased expression or production of CD86, PD-L1, nitric oxide, and IL-6, increased expression of PD-L2, and having a potent capacity to retain their phenotype on secondary proinflammatory stimulation. M2 microglia induced regulatory T cells, suppressed T-cell proliferation, and downmodulated M1-associated receptor expression in M1 macrophages. Myelin oligodendrocyte glycoprotein (MOG)-induced EAE was induced in DBA/1 mice and at different time points (0, 5, 12, or 15 days postimmunization) 3 × 10⁵ M2 microglia were transferred intranasally. A single transfer of M2 microglia attenuated the severity of established EAE, which was particularly obvious when the cells were injected at 15 days postimmunization. M2 microglia-treated mice had reduced inflammatory responses and less demyelination in the CNS. Our findings demonstrate that adult M2 microglia therapy represents a novel intervention that alleviated established EAE and that this therapeutic principle may have relevance for treatment of MS patients.

Intranasal delivery of FSD-C10, a novel Rho kinase inhibitor, exhibits therapeutic potential in experimental autoimmune encephalomyelitis

Viewing multiple sclerosis (MS) as both neuroinflammation and neurodegeneration has major implications for therapy, with neuroprotection and neurorepair needed in addition to controlling neuroinflammation in the central nervous system (CNS). While Fasudil, an inhibitor of Rho kinase (ROCK), is known to suppress experimental autoimmune encephalomyelitis (EAE), an animal model of MS, it relies on multiple, short-term injections, with a narrow safety window. In this study, we explored the therapeutic effect of a novel ROCK inhibitor FSD-C10, a Fasudil derivative, on EAE. An important advantage of this derivative is that it can be used via non-injection routes; intranasal delivery is the preferred route because of its efficient CNS delivery and the much lower dose compared with oral delivery. Our results showed that intranasal delivery of FSD-C10 effectively ameliorated the clinical severity of EAE and CNS inflammatory infiltration and promoted neuroprotection. FSD-C10 effectively induced CNS production of the immunoregulatory cytokine interleukin-10 and boosted expression of nerve growth factor and brain-derived neurotrophic factor proteins, while inhibiting activation of p-nuclear factor-κB/p65 on astrocytes and production of multiple pro-inflammatory cytokines. In addition, FSD-C10 treatment effectively induced CD4(+) CD25(+) , CD4(+) FOXP3(+) regulatory T cells. Together, our results demonstrate that intranasal delivery of the novel ROCK inhibitor FSD-C10 has therapeutic potential in EAE, through mechanisms that possibly involve both inhibiting CNS inflammation and promoting neuroprotection.

Intranasal delivery of central nervous system-retargeted human mesenchymal stromal cells prolongs treatment efficacy of experimental autoimmune encephalomyelitis

Treatment with mesenchymal stromal cells (MSCs) is currently of interest for a number of diseases including multiple sclerosis. MSCs are known to target inflamed tissues, but in a therapeutic setting their systemic administration will lead to few cells reaching the brain. We hypothesized that MSCs may target the brain upon intranasal administration and persist in central nervous system (CNS) tissue if expressing a CNS-targeting receptor. To demonstrate proof of concept, MSCs were genetically engineered to express a myelin oligodendrocyte glycoprotein-specific receptor. Engineered MSCs retained their immunosuppressive capacity, infiltrated into the brain upon intranasal cell administration, and were able to significantly reduce disease symptoms of experimental autoimmune encephalomyelitis (EAE). Mice treated with CNS-targeting MSCs were resistant to further EAE induction whereas non-targeted MSCs did not give such persistent effects. Histological analysis revealed increased brain restoration in engineered MSC-treated mice. In conclusion, MSCs can be genetically engineered to target the brain and prolong therapeutic efficacy in an EAE model.

Bone Marrow-Derived Stem Cells and Strategies for Treatment of Nervous System Disorders: Many Protocols, and Many Results

Bone marrow stem cells are the best known stem cell type and have been employed for more than 50 years, especially in pathologies of the hematopoietic and immune systems. However, their therapeutic potential is much broader, and they can also be employed to palliate neural diseases. Apart from their plastic properties, these cells lack the legal or ethical constraints of other stem cell populations, that is, embryonic stem cells. Current research addressing the integration of bone marrow-derived cells into the neural circuits of the central nervous system, their features, and applications is a hotspot in neurobiology. Nevertheless, as in other leading research lines the efficacy and possibilities of their application depend on technical procedures, which are still far from being standardized. Accordingly, for efficient research this large range of variants should be taken into account as they could lead to unexpected results. Rather than focusing on clinical aspects, this review offers a compendium of the methodologies aimed at providing a guide for researchers who are working in the field of bone marrow transplantation in the central nervous system. It seeks to be useful for both introductory and trouble-shooting purposes, and in particular for dealing with the large array of bone marrow transplantation protocols available.

Roadmap of miR-122-related clinical application from bench to bedside

INTRODUCTION

microRNA (miRNA) regulates target gene expression to influence many physiological and pathophysiological processes. The liver-specific miRNA, miR-122, contributes to liver function and plays a very important role in hepatic diseases including the viral hepatitis C (HCV). For this reason, developing an miR-122-related clinical application could be very useful in managing or treating many hepatic disorders.

AREAS COVERED

This review introduces the basic concepts of miRNA and miR-122. It also discusses the possibility of miR-122 as a biomarker and summarizes the results of anti-miR-122 treatment from basic research to a Phase IIa clinical trial. Furthermore, the authors discuss the potential opportunities and challenges found in clinical trials with miravirsen.

EXPERT OPINION

miR-122 may be a useful biomarker as both a diagnostic and prognostic tool. Furthermore, miravirsen is a novel treatment with great potential for hepatic disease treatment, especially in HCV. However, there is certainly the need for future investigations to better determine whether miR-122 is really specific for liver. It is also important to elucidate whether miR-122 is actually specific for HCV genome and further investigate the therapeutic potential of miravirsen. Only once these studies have been completed can anti-miR-122 treatment potentially enter the clinical practice.