Blood-brain barrier structure and function and the challenges for CNS drug delivery

Evaluation of the distribution of the boron neutron capture therapy drug 4-borono-L-phenylalanine (BPA) in a rat brain tumor model using liquid chromatography/tandem mass spectrometry (LC-MS/MS)

The blood-brain barrier (BBB) restricts drug delivery to the brain. Although recent advancements have led to the development of drugs designed to bypass the BBB, the treatment of neurological disorders remains a clinical challenge. In this study, we quantitatively evaluated the distribution of 4-borono-L-phenylalanine (BPA), a drug used in boron neutron capture therapy (BNCT), in brain tumors. Recent findings have shown that the BBB exhibits heterogeneity in drug uptake, particularly in the context of brain tumors, which often leads to treatment failure and/or recurrence. Understanding the heterogeneity of the BBB is crucial to facilitate effective drug delivery and treatment of brain tumors using BNCT. Herein, we performed boron distribution mapping in 26 brain segments from a rat model of metastatic melanoma using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The boron concentrations measured using LC-MS/MS in tumor and cerebral cortex samples were relatively close to those obtained via inductively-coupled plasma atomic emission spectrometry (ICP-AES) under the same administration conditions, suggesting that the measurements obtained with LC-MS/MS were plausible. The boron distribution in the tumor, obtained by LC-MS/MS, suggested heterogeneous accumulation. In our next study, we will investigate a method to determine the BPA concentration in smaller samples (less than 1 mg) or lower concentration of BPA in order to capture the characteristics of tumor heterogeneity in detail.

Nanomedicine for targeting brain Neurodegeneration: Critical barriers and circadian rhythm Considerations

The development of novel therapies for central nervous system (CNS) diseases, particularly neurodegenerative disorders like Alzheimer's disease (AD), is a critical global health priority. Biotherapeutics, such as monoclonal antibodies (mAbs) and RNA-based therapies, have shown potential for treating brain disorders. However, their clinical progress is limited by their difficult access to their brain targets. At the preclinical level, nanotechnology has been shown, to help these molecules overcome the biological barriers that imped their adequate brain delivery. This review highlights advances in this area and the challenges for the translation to the clinic. Key nanotechnology-based strategies, such as surface modifications utilizing endogenous protein corona, functionalization with targeting ligands, therapeutic ultrasound-mediated microbubble oscillation were particularly analyzed. Additionally, in line with the focus of the Special Issue, this review integrates the concept of chronotherapy, with a focus on AD treatment, highlighting the idea that, by aligning nanoparticle (NP)-based drug delivery with circadian rhythms, it may be possible to improve therapeutic outcomes. Finally, the article analyzes current strategies in CNS drug delivery in clinical trials and provides future directions within this frame, notably in the area of AD.

Smart Bioelectronics for Real-Time Diagnosis and Therapy of Body Organ Functions

Noncommunicable diseases (NCDs) associated with cardiovascular, neurological, and gastrointestinal disorders remain a leading cause of global mortality, sounding the alarm for the urgent need for better diagnostic and therapeutic solutions. Wearable and implantable biointegrated electronics offer a groundbreaking solution, combining real-time, high-resolution monitoring with innovative treatment capabilities tailored to specific organ functions. In this comprehensive review, we focus on the diseases affecting the brain, heart, gastrointestinal organs, bladder, and adrenal gland, along with their associated physiological parameters. Additionally, we provide an overview of the characteristics of these parameters and explore the potential of bioelectronic devices for in situ sensing and therapeutic applications and highlight the recent advancements in their deployment across specific organs. Finally, we analyze the current challenges and prospects of implementing closed-loop feedback control systems in integrated sensor-therapy applications. By emphasizing organ-specific applications and advocating for closed-loop systems, this review highlights the potential of future bioelectronics to address physiological needs and serves as a guide for researchers navigating the interdisciplinary fields of diagnostics, therapeutics, and personalized medicine.

Rebamipide (Mucosta®), a clinically approved drug, alleviates neuroinflammation and dopaminergic neurodegeneration in a Parkinson's disease model

BACKGROUND

Parkinson's disease (PD) is characterized by dopaminergic neuron loss, neuroinflammation, and motor dysfunction. PD is a multifactorial disease, with neuroinflammation driven by NLRP3 inflammasome activation representing an important component of its pathological progression. Therefore, we aimed to evaluate the therapeutic potential of rebamipide (Mucosta®), a clinically approved anti-inflammatory agent, in PD by targeting the NLRP3 inflammasome. Specifically, we examined the effects of rebamipide on neuroinflammation, dopaminergic neuron preservation, and motor deficits using BV2 microglia cells and a 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced mouse model.

MAIN BODY

Rebamipide alleviated microglial activation and downstream neuroinflammation by suppressing the NLRP3-NEK7 interaction, resulting in dopaminergic neuron protection in the MPTP-induced PD model. Rebamipide downregulated IL-1β levels in BV2 microglia cells treated with α-synuclein and MPP+. Molecular docking analysis revealed a high binding affinity between rebamipide and the NLRP3-NEK7 interaction interface. Surface plasmon resonance analysis confirmed the direct binding of rebamipide to NLRP3, with notable kinetic affinity, supporting its role as a novel NLRP3 inflammasome inhibitor. Rebamipide significantly downregulated IL-1β levels, microglial activation, and dopaminergic neuron loss in the MPTP mouse model by disrupting inflammasome activation. Rebamipide preserved dopamine levels in the striatum and improved motor deficits, including bradykinesia and motor coordination. The neuroprotective effects of rebamipide were neutralized in NLRP3 knockout mice, confirming the dependency of its action on NLRP3.

CONCLUSION

Considering its established clinical use, this study supports repurposing rebamipide for treating PD and other NLRP3 inflammasome-driven neuroinflammatory diseases.

The curse of blood-brain barrier and blood-tumor barrier in malignant brain tumor treatment

The blood-brain barrier (BBB) is crucial for brain homeostasis but is a major obstacle in delivering anticancer drugs to brain tumors. However, this perspective requires re-evaluation, particularly for malignant brain tumors, such as gliomas and brain metastases. In these aggressive tumors, the BBB undergoes significant alterations, leading to the formation of a more permeable blood-tumor barrier. While this increased permeability allows better drug penetration, heterogeneity in blood-tumor barrier (BTB) integrity across different tumor regions remains a challenge. Additionally, the main challenge in treating brain tumors lies not in BBB penetration but in the lack of effective drugs. Conventional chemotherapies, including temozolomide and nitrosourea agents, have shown limited efficacy, and resistance mechanisms often reduce their long-term benefits. The "BBB curse" has often been blamed for the slow progress in drug development. However, emerging evidence suggests that even larger-molecule therapies, such as antibody-drug conjugates, can successfully target brain tumors. This review aims to critically reassess the roles of the BBB and BTB in brain tumor therapy, highlighting their impact on drug delivery and evaluating the current landscape of chemotherapeutic strategies. Furthermore, it explores new approaches to overcome treatment limitations, emphasizing the need for personalized and targeted therapeutic strategies.

Exosome-powered neuropharmaceutics: unlocking the blood-brain barrier for next-gen therapies

BACKGROUND

The blood-brain barrier (BBB) presents a formidable challenge in neuropharmacology, limiting the delivery of therapeutic agents to the brain. Exosomes, nature's nanocarriers, have emerged as a promising solution due to their biocompatibility, low immunogenicity, and innate ability to traverse the BBB. A thorough examination of BBB anatomy and physiology reveals the complexities of neurological drug delivery and underscores the limitations of conventional methods.

MAIN BODY

This review explores the potential of exosome-powered neuropharmaceutics, highlighting their structural and functional properties, biogenesis, and mechanisms of release. Their intrinsic advantages in drug delivery, including enhanced stability and efficient cellular uptake, are discussed in detail. Exosomes naturally overcome BBB barriers through specific translocation mechanisms, making them a compelling vehicle for targeted brain therapies. Advances in engineering strategies, such as genetic and biochemical modifications, drug loading techniques, and specificity enhancement, further bolster their therapeutic potential. Exosome-based approaches hold immense promise for treating a spectrum of neurological disorders, including Alzheimer's, Parkinson's, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), brain tumors, stroke, and psychiatric conditions.

CONCLUSION

By leveraging their innate properties and engineering innovations, exosomes offer a versatile platform for precision neurotherapeutics. Despite their promise, challenges remain in clinical translation, including large-scale production, standardization, and regulatory considerations. Future research directions in exosome nanobiotechnology aim to refine these therapeutic strategies, unlocking new avenues for treating neurological diseases. This review underscores the transformative impact of exosome-based drug delivery, paving the way for next-generation therapies that can effectively penetrate the BBB and revolutionize neuropharmacology.

Functionalized Nanoparticles: A Promising Approach for Effective Management of Alzheimer's Disease

The severe neurodegenerative disease known as Alzheimer's disease (AD) is typified by a progressive loss of memory and cognitive function. The prevalence of AD is rising due to an aging global population, calling for novel treatment strategies. A potential treatment option for AD that shows promise is the use of functionalized nanoparticles (NPs). Recent developments in the synthesis, design, and use of functionalized NPs in AD therapy are examined in this review. An outline of the pathophysiological mechanisms underlying AD is given in the first section, focusing on the roles played by tau protein aggregates and amyloid-beta plaques in the development of the illness. We then explore the many approaches used to functionalize NPs, such as surface alterations and bioconjugation methods, which enable accurate drug administration, targeted delivery, and enhanced biocompatibility. The review also emphasizes the therapeutic potential of functionalized NPs, highlighting their capacity to improve neuroprotection, lower amyloid-beta aggregation, and improve blood-brain barrier penetration. The potential of NPs as a tool for disease modification and symptom relief is highlighted by recent pre-clinical and clinical research. Concerns about toxicity and safety are also covered, underscoring the significance of thorough testing and the field's future directions. Functionalized NPs have great promise as a multimodal strategy to treat AD, offering patients hope for better quality of life, early diagnosis, and efficient disease treatment. This study highlights the growing role of nanotechnology in the search for novel and potent therapies for AD.

Review: The potential role of placental extracellular vesicles in blood-brain barrier disruption and neuroinflammation in preeclampsia

Preeclampsia is a complex pregnancy disorder characterized by hypertension and multisystem organ damage, notably affecting the liver, kidneys, and brain. Eclampsia, a severe form of preeclampsia, is marked by the sudden onset of generalized tonic-clonic seizures. Brain complications, including eclampsia, are responsible for 60-70 % of preeclampsia-related maternal deaths, particularly in low-income regions. Despite the significant impact of brain complications in preeclampsia, their underlying pathophysiology remains unclear. Evidence suggests that brain edema in preeclampsia and eclampsia results from disruption of the blood-brain barrier (BBB). Although direct analysis of the BBB is challenging, in vitro studies indicate that plasma from women with preeclampsia can compromise the BBB, with the specific circulating factors involved still unidentified. Among the potential culprits, recent findings highlight placental-derived small extracellular vesicles (PDsEVs) as key players in BBB disruption observed in preeclampsia. This review examines the role of PDsEVs in the pathophysiology of brain edema associated with preeclampsia, emphasizing areas for future research, including neuroinflammation and neuron dysfunction. Additionally, we discuss the protective role of magnesium sulfate in these processes.

Advances in PET Imaging of α7 Nicotinic Receptors: From Radioligand Development to CNS Applications

Positron emission tomography (PET) has significantly advanced our understanding of the brain by enabling non-invasive imaging and quantification of molecular processes, including receptor binding. In this review, we explore the development and application of PET radioligands targeting the α7 nicotinic acetylcholine receptor (α7 nAChR), a receptor implicated in various central nervous system (CNS) diseases, such as Alzheimer's disease, schizophrenia and cognitive disorders. Despite challenges associated with the low density of α7 nAChRs and difficulties in achieving adequate brain penetration, several promising radioligands have been developed, including 11C-(R)-MeQAA, 11C-NS14492 and 18F-ASEM. These radioligands facilitate the evaluation of the 'three pillars of survival' in drug development: tissue accessibility, target engagement and downstream pharmacology. PET imaging offers critical insights into drug distribution across the blood-brain barrier, receptor occupancy and the pharmacodynamic effects of α7 nAChR-targeted therapies. By reviewing current radioligands and their applications, we highlight the potential of PET imaging to deepen our understanding of α7 nAChR-mediated signalling pathways and its implications for CNS drug discovery. Future innovations in radioligand development, including more selective and brain-penetrant compounds, will be key to fully realizing the potential of PET imaging in α7 nAChR-targeted research and treatment.

PepH3-modified nanocarriers for delivery of therapeutics across the blood-brain barrier

BACKGROUND

Nanocarriers targeting the blood-brain barrier (BBB) are promising drug delivery systems to enhance the penetration of therapeutic molecules into the brain. Immunotherapy, particularly monoclonal antibodies designed to bind amyloid-beta peptides have become a promising strategy for Alzheimer's disease, but ensuring efficacy and safety is challenging and crucial for these therapies. Our aim was to develop an innovative nanocarriers conjugated with PepH3, a cationic peptide derived from Dengue virus type-2 capsid protein that crosses the BBB and acts as a shuttle peptide for the encapsulated single domain antibody (sdAb) recognizing Aβ oligomers.

RESULTS

PepH3 peptide enhanced the uptake of the nanoparticles (NPs) into brain endothelial cells, and transcytosis of sdAb, as a potential therapeutic molecule, across both rat and human BBB culture models. The cargo uptake was a temperature dependent active process that was reduced by metabolic and endocytosis inhibitors. The cellular uptake of the cationic PepH3-tagged NPs decreased when the negative surface charge of brain endothelial cells became more positive after treatments with a cationic lipid or with neuraminidase by digesting the glycocalyx. The NPs colocalized mostly with endoplasmic reticulum and Golgi apparatus and not with lysosomes, indicating the cargo may avoid cellular degradation.

CONCLUSIONS

Our results support that combination of NPs with a potential brain shuttle peptide such as PepH3 peptide can improve the delivery of antibody fragments across the BBB.

Advancements and challenges in CAR T cell therapy for pediatric brain tumors: A review

Chimeric Antigen Receptor (CAR) T cell therapy represents a groundbreaking advancement in immunotherapy, initially gaining FDA approval for treating hematological malignancies. This therapy has shown promising results in solid tumors, particularly in pediatric brain tumors, which are the leading cause of cancer-related death in children. CAR T cells are engineered to target specific antigens on tumor cells, thereby reducing off-target effects and increasing the cytotoxic impact on cancer cells. Over the years, CAR T cell technology has evolved through five generations, each enhancing the structure, functionality, and safety of these cells. Despite these advancements, the application of CAR T cells in solid tumors, especially within the central nervous system (CNS), faces significant challenges. These include the physical barrier posed by the blood-brain barrier (BBB), the immunosuppressive tumor microenvironment (TME), and the heterogeneity of tumor antigens. The review discusses several promising antigenic targets for CAR T cells in pediatric brain tumors, such as HER2, EphA2, IL-13Rα2, and Survivin, which have been explored in recent clinical trials. These trials have shown early promise in improving patient outcomes, though the risks of cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) remain concerns. The future of CAR T cell therapy lies in overcoming these barriers through innovative approaches like "Armored CARs" or TRUCKs, designed to modulate the TME and improve CAR T cell efficacy in solid tumors. Additionally, combination therapies and safety switches in next-generation CAR T cells are being explored to enhance therapeutic potential while minimizing adverse effects.

Advancements in Nanoemulsion-Based Drug Delivery Across Different Administration Routes

Nanoemulsions (NEs) have emerged as effective drug delivery systems over the past few decades due to their multifaceted nature, offering advantages such as enhanced bioavailability, protection of encapsulated compounds, and low toxicity. In the present review, we focus on advancements in drug delivery over the last five years across (trans)dermal, oral, ocular, nasal, and intra-articular administration routes using NEs. Rational selection of components, surface functionalization, incorporation of permeation enhancers, and functionalization with targeting moieties are explored for each route discussed. Additionally, apart from NEs, we explore NE-based drug delivery systems (e.g., NE-based gels) while highlighting emerging approaches such as vaccination and theranostic applications. The growing interest in NEs for drug delivery purposes is reflected in clinical trials, which are also discussed. By summarizing the latest advances, exploring new strategies, and identifying critical challenges, this review focuses on developments for efficient NE-based therapeutic approaches.

Use of Quantum Dots as Nanotheranostic Agents: Emerging Applications in Rare Genetic Diseases

Rare genetic diseases (RGDs) affect a small percentage of the global population but collectively have a substantial impact due to their diverse manifestations. Although the precise reasons behind these diseases remain unclear, roughly 80% of cases are genetically linked. Recent efforts focus on understanding pathology and developing new diagnostic and therapeutic approaches for RGDs. However, there persists a gap between fundamental research and clinical therapeutic approaches, where advancements in nanotechnology offer promising improvements. In this context, nanosized light-emitting quantum dots (QDs), ranging from 2-10 nm, are promising materials for diverse applications. Their size-tunable light emission, high quantum yield, and photostability allow for precise tracking of cargo. Additionally, QDs can be functionalized with therapeutic agents, antibodies, or peptides to target specific cellular pathways, enhancing treatment efficacy while minimizing side effects. By combining diagnostic and therapeutic capabilities in a single platform, QDs thus offer a versatile and powerful approach to tackle rare genetic disorders. Despite several reviews on various therapeutic applications of QDs, their utilization in the specific domain of RGDs is not well documented. This review highlight QDs' potential in diagnosing and treating certain RGDs and addresses the challenges limiting their application.

Cancer brain metastasis: molecular mechanisms and therapeutic strategies

Brain metastases (BMs) are the most common intracranial tumors in adults and the major cause of cancer-related morbidity and mortality. The occurrence of BMs varies according to the type of primary tumors with most frequence in lung cancer, melanoma and breast cancer. Among of them, lung cancer has been reported to have a higher risk of BMs than other types of cancers with 40 ~ 50% of such patients will develop BMs during the course of disease. BMs lead to many neurological complications and result in a poor quality of life and short life span. Although the treatment strategies were improved for brain tumors in the past decades, the prognosis of BMs patients is grim. Poorly understanding of the molecular and cellular characteristics of BMs and the complicated interaction with brain microenvironment are the major reasons for the dismal prognosis of BM patients. Recent studies have enhanced understanding of the mechanisms of BMs. The newly identified potential therapeutic targets and the advanced therapeutic strategies have brought light for a better cure of BMs. In this review, we summarized the mechanisms of BMs during the metastatic course, the molecular and cellular landscapes of BMs, and the advances of novel drug delivery systems for overcoming the obstruction of blood-brain barrier (BBB). We further discussed the challenges of the emerging therapeutic strategies, such as synergistic approach of combining targeted therapy with immunotherapy, which will provide vital clues for realizing the precise and personalized medicine for BM patients in the future.

Alanine and glutathione targeting of dopamine- or ibuprofen-coupled polypeptide nanocarriers increases both crossing and protective effects on a blood-brain barrier model

BACKGROUND

Targeting the blood-brain barrier (BBB) is a key step for effective brain delivery of nanocarriers. We have previously discovered that combinations of BBB nutrient transporter ligands alanine and glutathione (A-GSH), increase the permeability of vesicular and polypeptide nanocarriers containing model cargo across the BBB. Our aim was to investigate dopamine- and ibuprofen-coupled 3-armed poly(L-glutamic acid) nanocarriers targeted by A-GSH for transfer across a novel human co-culture model with induced BBB properties. In addition, the protective effect of ibuprofen containing nanoparticles on cytokine-induced barrier damage was also measured.

METHOD

Drug-coupled nanocarriers were synthetized and characterized by dynamic light scattering and transmission electron microscopy. Cellular effects, uptake, and permeability of the nanoparticles were investigated on a human stem cell-based co-culture BBB model with improved barrier properties induced by a small molecular cocktail. The model was characterized by immunocytochemistry and permeability for marker molecules. Nanocarrier uptake in human brain endothelial cells and midbrain organoids was quantified by spectrofluorometry and visualized by confocal microscopy. The mechanisms of cellular uptake were explored by addition of free targeting ligands, endocytic and metabolic inhibitors, co-localization of nanocarriers with intracellular organs, and surface charge modification of cells. The protective effect of ibuprofen-coupled nanocarriers was investigated against cytokine-induced barrier damage by impedance and permeability measurements.

RESULTS

Targeted nanoformulations of both drugs showed elevated cellular uptake in a time-dependent, active manner via endocytic mechanisms. Addition of free ligands inhibited the cellular internalization of targeted nanocarriers suggesting the crucial role of ligands in the uptake process. A higher permeability across the BBB model was measured for targeted nanocarriers. After crossing the BBB, targeted dopamine nanocarriers subsequently entered midbrain-like organoids derived from healthy and Parkinson's disease patient-specific stem cells. The ibuprofen-coupled targeted nanocarriers showed protective effects against cytokine-induced barrier damage.

CONCLUSION

BBB-targeted polypeptide nanoparticles coupled to therapeutic molecules were effectively taken up by brain organoids or showing a BBB protective effect indicating potential applications in nervous system pathologies.

Permeability Benchmarking: Guidelines for Comparing in Silico, in Vitro, and in Vivo Measurements

Permeability is a measure of the degree to which cells can transport molecules across biological barriers. Units of permeability are distance per unit time (typically cm/s), where accurate measurements are needed to define drug delivery in homeostasis and to model dysfunction occurring during disease. This perspective offers a set of community-led guidelines to benchmark permeability data across multidisciplinary approaches and different biological contexts. First, we lay out the analytical framework for three methodologies to calculate permeability: in silico assays using either transition-based counting or the inhomogeneous-solubility diffusion approaches, in vitro permeability assays using cells cultured in 2D or 3D geometries, and in vivo assays utilizing in situ brain perfusion or multiple time-point regression analysis. Then, we demonstrate a systematic benchmarking of in silico to both in vitro and in vivo, depicting the ways in which each benchmarking is sensitive to the choices of assay design. Finally, we outline seven recommendations for best practices in permeability benchmarking and underscore the significance of tailored permeability assays in driving advancements in drug delivery research and development. Our exploration encompasses a discussion of "generic" and tissue-specific biological barriers, including the blood-brain barrier (BBB), which is a major hurdle for the delivery of therapeutic agents into the brain. By addressing challenges in reconciling simulated data with experimental assays, we aim to provide insights essential for optimizing accuracy and reliability in permeability modeling.

The Secretome of Brain Endothelial Cells Exposed to the Pyrrolizidine Alkaloid Monocrotaline Induces Astrocyte Reactivity and Is Neurotoxic

Monocrotaline (MCT) has well-characterized hepatotoxic and pneumotoxic effects attributed to its active pyrrole metabolites. Studies have previously shown that astrocytes and neurons are targets of MCT, and that toxicity is attributed to astrocyte P450 metabolism to reactive metabolites. However, little is known about MCT toxicity and metabolism by brain endothelial cells (BECs), cells that, together with astrocytes, are specialized in xenobiotic metabolism and neuroprotection. Therefore, in the present study, we evaluated the toxicity of MCT in BECs, and the effects on astrocyte reactivity and neuronal viability in vitro. MCT was purified from Crotalaria retusa seeds. BECs, obtained from the brain of adult Wistar rats, were treated with MCT (1-500 µM), and cell viability and morphology were analyzed after 24-72 h of treatment. Astrocyte/neuron co-cultures were prepared from the cortex of neonatal and embryonic Wistar rats, and the cultures were exposed to conditioned medium (secretome) derived from BECs previously treated with MCT (100-500 µM, SBECM100/500). MCT was not toxic to BECs at the concentrations used and induced a concentration-dependent increase in cell dehydrogenase after 72 h of treatment, suggesting resistance to damage and drug metabolism. However, exposure of astrocyte/neuron co-cultures to the SBECM for 24 h induced changes in the cell morphology, vacuolization, and overexpression of GFAP in astrocytes, characterizing astrogliosis, and neurotoxicity with a reduction in the length of neurites labeled for β-III-tubulin, effects that were MCT concentration-dependent. These results support the hypothesis that MCT neurotoxicity may be due to products of its metabolism by components of the BBB such as BECs and astrocytes, which may be responsible for the brain lesions and symptoms observed after intoxication.

Towards a New Dawn for Neuro-Oncology: Nanomedicine at the Service of Drug Delivery for Primary and Secondary Brain Tumours

(1) Background/Objectives: Primary and secondary brain tumours often hold devastating prognoses and low survival rates despite the application of maximal neurosurgical resection, and state-of-the-art radiotherapy and chemotherapy. One limiting factor in their management is that several antineoplastic agents are unable to cross the blood-brain barrier (BBB) to reach the tumour microenvironment. Nanomedicine could hold the potential to become an effective means of drug delivery to overcome previous hurdles towards effective neuro-oncological treatments. (2) Methods: A scoping review following the PRISMA-ScR guidelines and checklist was conducted using key terms input into PubMed to find articles that reflect emerging trends in the utilisation of nanomedicine in drug delivery for primary and secondary brain tumours. (3) Results: The review highlights various strategies by which different nanoparticles can be exploited to bypass the BBB; we provide a synthesis of the literature on the ongoing contributions to therapeutic protocols based on chemotherapy, immunotherapy, focused ultrasound, radiotherapy/radiosurgery, and radio-immunotherapy. (4) Conclusions: The emerging trends summarised in this scoping review indicate encouraging advantageous properties of nanoparticles as potential effective drug delivery mechanisms; however, there are still nanotoxicity issues that largely remain to be addressed before the translation of these innovations from laboratory to clinical practice.

Discovery of Brain-Penetrative Negative Allosteric Modulators of NMDA Receptors Using FEP-Guided Structure Optimization and Membrane Permeability Prediction

N-Methyl-d-aspartate (NMDA) receptors, a subtype of ionotropic glutamate receptors in the central nervous system (CNS), have garnered attention for their role in brain disorders. Specifically, GluN2A-containing NMDA receptors have emerged as a potential therapeutic target for the treatment of depressive disorders and epilepsy. However, the development of GluN2A-containing NMDA receptor-selective antagonists, represented by N-(4-(2-benzoylhydrazine-1-carbonyl)benzyl)-3-chloro-4-fluorobenzenesulfonamide (TCN-201) and its derivatives, faces a significant challenge due to their limited ability to penetrate the blood-brain barrier (BBB), hampering their in vivo characterization and further advancement. In this study, we reported a series of 2-((5-(phemylamino)-1,3,4-thiadiazol-2-yl)thio)-N-(cyclohexylmethyl)acetamide derivatives, achieved through a structure-guided optimization strategy using free energy perturbation (FEP) and BBB permeability estimation. Through systematic exploration of various phenyl substitutions, compound 1f emerged as a standout compound, demonstrating substantially enhanced inhibitory activity compared with the lead compound TCN-213. Compound 1f not only displayed satisfactory BBB permeability but also showed antidepressant-like potency in the hydrocortisone-induced zebrafish depression-like model. All results position it as a promising candidate for developing innovative therapeutics for NMDA receptor-related disorders.

Systematic Review of Pre-Clinical Systems Using Artificial Microenvironments and Anti-Migratory Drugs to Control Migration of Glioblastoma Cells

BACKGROUND

Glioblastoma multiforme (GBM) is the most prevalent primary brain tumour, with an incidence of 2 per 100,000. The standard clinical treatments do not sufficiently target cell migration and invasion, leading to recurrence after surgical resection and resistance after chemotherapy and radiotherapy. Pre-clinical studies are being conducted to construct artificial substrates that can mimic the tumour microenvironment (TME) to prevent GBM cells from migrating along their primary route through blood vessels and white matter tracts. Alongside, targeted therapies using anti-migratory or ‘migrastatic’ drugs are also being developed. This study aimed to review the therapeutic translational strategies emerging from the study of the GBM microenvironment and anti-migratory drugs.

METHODS

A systematic literature search was carried out using search key terms and synonyms. Full-paper screening was performed based on specific inclusion and exclusion criteria.

RESULTS

From the systems interrogated, the ‘Nanofibre’ assay is suitable to simulate white matter tracts, while hydrogel-based invasion assays and GBM cerebral organoid (GLICO) mimic the brain extracellular matrix. Inhibitors with anti-migratory activity found in this study are active involving distinct molecular mechanisms and have been tested on cell migration assays.

CONCLUSION

Overall, we have analysed therapeutic strategies emerging from an artificial GBM TME approach and from the identification of anti-migratory inhibitors. Both carry potential to improve treatment options to prevent tumour dissemination and spread for GBM.

Nanoparticle Interactions with the Blood Brain Barrier: Insights from Drosophila and Implications for Human Astrocyte Targeted Therapies

This review explores the intricate connections between Drosophila models and the human blood-brain barrier (BBB) with nanoparticle-based approaches for neurological treatment. Drosophila serves as a powerful model organism due to its evolutionary conservation of key biological processes, particularly in the context of the BBB, which is formed by glial cells that share structural and functional similarities with mammalian endothelial cells. Recent advancements in nanoparticle technology have highlighted their potential for effective drug delivery across the BBB, utilizing mechanisms such as passive diffusion, receptor-mediated transcytosis, and carrier-mediated transport. The ability to engineer nanoparticles with specific physicochemical properties-such as size, surface charge, and functionalization-enhances their targeting capabilities, particularly towards astrocytes, which play a crucial role in maintaining BBB integrity and responding to neuroinflammation. Insights gained from Drosophila studies have informed the design of personalized nanomedicine strategies aimed at treating neurodegenerative diseases, including Alzheimer's, Parkinson's disease etc. As research progresses, the integration of findings from Drosophila models with emerging humanized BBB systems will pave the way for innovative therapeutic approaches that improve drug delivery and patient outcomes in neurological disorders.

Advanced tissue technologies of blood-brain barrier organoids as high throughput toxicity readouts in drug development

Recent advancements in engineering Complex in vitro models (CIVMs) such as Blood-brain barrier (BBB) organoids offer promising platforms for preclinical drug testing. However, their application in drug development, and especially for the regulatory purposes of toxicity assessment, requires robust and reproducible techniques. Here, we developed an adapted set of orthogonal image-based tissue methods including hematoxylin and eosin staining (HE), immunohistochemistry (IHC), multiplex immunofluorescence (mIF), and Matrix Assisted Laser Desorption/Ionization Mass Spectrometry Imaging (MALDI-MSI) to validate CIVMs for drug toxicity assessments. We developed an artificial intelligence (AI) algorithm to increase the throughput and the reliability of histomorphologic evaluations of apoptosis for in vitro toxicity studies. Our data highlight the potential to integrate advanced morphology-based readouts such as histological techniques and digital pathology algorithms for use on CIVMs, as part of a standard preclinical drug development assessment.

Nanoparticles in CNS Therapeutics: Pioneering Drug Delivery Advancements

INTRODUCTION

The incidence of Central Nervous System (CNS) disorders, including Parkinson's disease, Alzheimer's disease, stroke, and malignancies, has risen significantly in recent decades, contributing to millions of deaths annually. Efficacious treatment of these disorders requires medicines targeting the brain. The Blood-brain Barrier (BBB) poses a formidable challenge to effective drug delivery to the brain, hindering progress in CNS therapeutics. This review explores the latest developments in nanoparticulate carriers, highlighting their potential to overcome BBB limitations.

OBJECTIVE

This study aimed to evaluate and summarise the critical factors and pathways in the nanoparticle- based CNS targeted drug delivery.

METHODS

An extensive literature search was conducted, comprising the initial development of nanoparticle- based CNS-targeted drug delivery approaches to the latest advancements using various online search tools.

RESULTS

The properties of nanoparticles, such as type of nanoparticles, size, shape, surface charge, hydrophobicity, and surface functionalisation, along with properties of the BBB during normal and pathological conditions and their impact on the delivery of nanoparticles across the BBB, are identified and discussed here.

CONCLUSION

Important properties and pathways that determine the penetration of nanoparticles across the CNS are reviewed in this article, along with recent advances in the field.

A narrative review on potential applications of spanlastics for nose-to-brain delivery of therapeutically active agents

Spanlastics, which are commonly referred to as elastic niosomes, presents a modified advancement in the area of colloidal system based drug delivery carriers. They are different from niosomes, which are non-ionic surfactant vesicles in having an edge activator. Initially, they were described as ocular drug delivery systems in 2011 by Kakkar and Kaur. Spanlastics have discovered a wide range of applications via different routes of administration. The purpose of this article is to provide information about spanlastics, a newly developed drug delivery system for the management of diseases pertaining to the Central Nervous System (CNS) via intranasal route. The article begins with the details on spanlastics and their composition, their benefits over traditional niosomes, and the mechanism underlying their enhanced absorption. Their applications through various routes of administration in a variety of diseases for a variety of drugs have been discussed. Furthermore, the article explains the nose to brain delivery channels and the advantages that this route offers over conventional delivery routes. Finally, the article discusses the studies encompassing the drug candidates that have been formulated as intranasal spanlastics for the management of different diseased conditions along with the future prospects of this emerging drug delivery system.

Therapeutic Potential of Ocimum basilicum L. Extract in Alleviating Autistic-Like Behaviors Induced by Maternal Separation Stress in Mice: Role of Neuroinflammation and Oxidative Stress

A confluence of genetic, environmental, and epigenetic factors shapes autism spectrum disorder (ASD). Early-life stressors like MS play a contributing role in this multifaceted neurodevelopmental disorder. This research was to explore the efficacy of Ocimum basilicum L. (O.B.) extract in mitigating behaviors reminiscent of autism prompted by maternal separation (MS) stress in male mice, focusing on its impact on neuroinflammation and oxidative stress. MS mice were treated with O.B. extract at varying dosages (20, 40, and 60 mg/kg) from postnatal days (PND) 51-53 to PND 58-60. Behavioral experiments, including the Morris water maze, three-chamber test, shuttle box, and resident-intruder test, were conducted post-treatment. The method of maternal separation involved separating the pups from their mothers for 3 h daily, from PND 2 to PND 14. Molecular analysis of hippocampal tissue was performed to assess gene expression of Toll-like receptor 4 (TLR4), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β). Hippocampal and serum malondialdehyde (MDA) levels and total antioxidant capacity (TAC) were measured. O.B. extract administration resulted in the amelioration of autistic-like behaviors in MS mice, as evidenced by improved spatial and passive avoidance memories and social interactions, as well as reduced aggression in behavioral tests. O.B. extract attenuated oxidative stress and neuroinflammation, as indicated by decreased MDA and increased TAC levels, as well as downregulation of TLR4, TNF-α, and IL-1β expression in the hippocampus. O.B. extract may offer a novel therapeutic avenue for ASD, potentially mediated through its anti-inflammatory and antioxidant properties.

Unraveling Neurological Drug Delivery: Polymeric Nanocarriers for Enhanced Blood-Brain Barrier Penetration

Treating neurological illnesses is challenging because the blood-brain barrier hinders therapeutic medications from reaching the brain. Recent advances in polymeric nanocarriers (PNCs), which improve medication permeability across the blood-brain barrier, may influence therapy strategies for neurological diseases. PNCs have several ways to deliver medications to the nervous system. This review article provides a summary of the parts and manufacturing methods involved in making PNCs. Additionally, it highlights the elements that result in PNCs having enhanced blood-brain barrier penetration. A combination of passive and active targeting strategies is used by PNCs intended to overcome the blood-brain barrier. Among these are micellar structures, nanogels, nanoparticles, cubosomes, and dendrimers. These nanocarriers, which are functionalized with certain ligands that target BBB transporters, enable the direct delivery of drugs to the brain. Mainly, the BBB prevents medications from entering the brain. Understanding the BBB's physiological and anatomical characteristics is necessary to get over this obstacle. Preclinical and clinical research demonstrates the safety and effectiveness of these PNCs, and their potential use in the treatment of neurological illnesses, including brain tumors, Parkinson's disease, and Alzheimer's disease, is discussed. Concerns that PNCs may have about their biocompatibility and possible toxicity are also covered in this review article. This study examines the revolutionary potential of PNCs in CNS drug delivery, potential roadblocks, ongoing research, and future opportunities for PNC design progress. PNCs open the door to more focused and efficient treatment for neurological illnesses by comprehending the subtleties of BBB penetration.

Exosomes as nature's nano carriers: Promising drug delivery tools and targeted therapy for glioma

Exosomes, minute vesicles originating from diverse cell types, exhibit considerable potential as carriers for drug delivery in glioma therapy. These naturally occurring nanocarriers facilitate the transfer of proteins, RNAs, and lipids between cells, offering advantages such as biocompatibility, efficient cellular absorption, and the capability to traverse the blood-brain barrier (BBB). In the realm of cancer, particularly gliomas, exosomes play pivotal roles in modulating tumor growth, regulating immunity, and combating drug resistance. Moreover, exosomes serve as valuable biomarkers for diagnosing diseases and assessing prognosis. This review aims to elucidate the therapeutic and diagnostic promise of exosomes in glioma treatment, highlighting the innovative advances in exosome engineering that enable precise drug loading and targeting. By circumventing challenges associated with current glioma treatments, exosome-mediated drug delivery strategies can enhance the efficacy of chemotherapy drugs like temozolomide and overcome drug resistance mechanisms. This review underscores the multifaceted roles of exosomes in glioma pathogenesis and therapy, underscoring their potential as natural nanocarriers for targeted therapy and heralding a new era of hope for glioma treatment.

Crosstalk Between the Nervous System and Colorectal Cancer

The nervous system is the dominant regulatory system in the human body. The traditional theory is that tumors lack innervation. However, an increasing number of studies have shown complex bidirectional interactions between tumors and the nervous system. Globally, colorectal cancer (CRC) is the third most common cancer. With the rise of tumor neuroscience, the role of nervous system imbalances in the occurrence and development of CRC has attracted increasing amounts of attention. However, there are still many gaps in the research on the interactions and mechanisms involved in the nervous system in CRC. This article systematically reviews emerging research on the bidirectional relationships between the nervous system and CRC, focusing on the following areas: (1) Effects of the nervous system on colon cancer. (2) Effects of CRC on the nervous system. (3) Treatment of CRC associated with the nervous system.

Immune cell infiltration and modulation of the blood-brain barrier in a guinea pig model of tuberculosis: Observations without evidence of bacterial dissemination to the brain

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb) infection, is a chronic inflammatory disease. Although typically associated with inflammation of the lungs and other peripheral tissues, increasing evidence has uncovered neurological consequences attributable to Mtb infection. These include deficits in memory and cognition, increased risk for neurodegenerative disease, and progressive neuropathology. Although the neurological effects of the disease, without CNS infection, have been characterized, the mechanism of neurotoxicity is unknown. We hypothesized that alterations to the blood-brain barrier (BBB) allows peripheral immune cells to enter the brain, initiating a neuroinflammatory response. To test this hypothesis, guinea pigs were exposed by aerosol to a laboratory and a clinical Mtb strain for 15 days. Following Mtb infection, proteins critical to BBB function, including claudin V and collagen IV, are modulated without evidence of bacterial dissemination to the brain. This is correlated with increased contact of astrocytic processes to vessels in the brain, as well as increased expression of the water channel protein aquaporin 4 (AQP4) on endfeet. Upon further investigation, we discovered the potential role of glial reactivity, which is increased following infection with both bacterial strains, in the progression of BBB changes and, ultimately, the permeability of peripheral immune cells into the brain. Through these data, we have obtained a preliminary understanding of the mechanisms of cellular stress in the brain following pulmonary Mtb infection which should be further investigated in future studies.

Effective Nose-to-Brain Delivery of Blood-Brain Barrier Impermeant Anti-IL-1β Antibody via the Minimally Invasive Nasal Depot (MIND) Technique

Treatment of neuroinflammation and neurodegenerative diseases using biologic therapies is limited due to the blood-brain barrier (BBB). This study explores a clinically validated approach to bypass the BBB for the purposes of direct central nervous system (CNS) delivery of antibodies using the Minimally Invasive Nasal Depot (MIND) technique. Using a lipopolysaccharide (LPS)-induced mouse model of neuroinflammation, we evaluated the efficacy of MIND in delivering a BBB impermeant full-length anti-IL-1β antibody. The results demonstrated that MIND delivery resulted in a significant reduction in IL-1β levels and microglial activation in relevant brain regions, notably outperforming conventional intravenous (IV) administration. These results underscore the ability of the MIND approach to transform the treatment landscape for a range of neurodegenerative diseases by enabling the targeted delivery of otherwise BBB impermeant therapeutics.

Nose to brain strategy coupled to nano vesicular system for natural products delivery: Focus on synaptic plasticity in Alzheimer's disease

A wide number of natural molecules demonstrated neuroprotective effects on synaptic plasticity defects induced by amyloid-β (Aβ) in ex vivo and in vivo Alzheimer's disease (AD) models, suggesting a possible use in the treatment of this neurodegenerative disorder. However, several compounds, administered parenterally and orally, are unable to reach the brain due to the presence of the blood-brain barrier (BBB) which prevents the passage of external substances, such as proteins, peptides, or phytocompounds, representing a limit to the development of treatment for neurodegenerative diseases, such as AD. The combination of nano vesicular systems, as colloidal systems, and nose to brain (NtB) delivery depicts a new nanotechnological strategy to overtake this limit and to develop new treatment approaches for brain diseases, including the use of natural molecules in combination therapy for AD. Herein, we will provide an updated overview, examining the literature of the last 20 years and using specific keywords that provide evidence on natural products with the ability to restore synaptic plasticity alterations in AD models, and the possible application using safe and non-invasive strategies focusing on nano vesicular systems for NtB delivery.

Neurons enhance blood-brain barrier function via upregulating claudin-5 and VE-cadherin expression due to glial cell line-derived neurotrophic factor secretion

Blood-brain barrier (BBB) prevents neurotoxins from entering central nervous system. We aimed to establish and characterize an in vitro triple co-culture BBB model consisting of brain endothelial cells hCMEC/D3, astrocytoma U251 cells, and neuroblastoma SH-SY5Y cells. Co-culture of SH-SY5Y and U251 cells markedly enhanced claudin-5 and VE-cadherin expression in hCMEC/D3 cells, accompanied by increased transendothelial electrical resistance and decreased permeability. Conditioned medium (CM) from SH-SY5Y cells (S-CM), U251 cells (U-CM), and co-culture of SH-SY5Y and U251 cells (US-CM) also promoted claudin-5 and VE-cadherin expression. Glial cell line-derived neurotrophic factor (GDNF) levels in S-CM and US-CM were significantly higher than CMs from hCMEC/D3 and U-CM. Both GDNF and US-CM upregulated claudin-5 and VE-cadherin expression, which were attenuated by anti-GDNF antibody and GDNF signaling inhibitors. GDNF increased claudin-5 expression via the PI3K/AKT/FOXO1 and MAPK/ERK pathways. Meanwhile, GDNF promoted VE-cadherin expression by activating PI3K/AKT/ETS1 and MAPK/ERK/ETS1 signaling. The roles of GDNF in BBB integrity were validated using brain-specific Gdnf silencing mice. The developed triple co-culture BBB model was successfully applied to predict BBB permeability. In conclusion, neurons enhance BBB integrity by upregulating claudin-5 and VE-cadherin expression through GDNF secretion and established triple co-culture BBB model may be used to predict drugs' BBB permeability.

Exosome Cargo in Neurodegenerative Diseases: Leveraging Their Intercellular Communication Capabilities for Biomarker Discovery and Therapeutic Delivery

The inexorable progression of neurodegenerative diseases (NDs), including Alzheimer's disease, Parkinson's disease, Huntington's disease, amyotrophic lateral sclerosis, and multiple sclerosis, is closely related to irreversible brain decline. Accurately characterizing pathophysiological features and identifying reliable biomarkers for early diagnosis and optimized treatment are critical. Hindered by the blood-brain barrier (BBB), obtaining sensitive monitoring indicators for disease progression and achieving efficient drug delivery remain significant challenges. Exosomes, endogenous nanoscale vesicles that carry key bioactive substances, reflect the intracellular environment and play an important role in cell signaling. They have shown promise in traversing the BBB, serving dual roles as potential biomarkers for NDs and vehicles for targeted drug delivery. However, the specific mechanisms by which exosome influence NDs are not fully understood, necessitating further investigation into their attributes and functionalities in the context of NDs. This review explores how exosomes mediate multifaceted interactions, particularly in exacerbating pathogenic processes such as oxidative stress, neuronal dysfunction, and apoptosis integral to NDs. It provides a comprehensive analysis of the profound impact of exosomes under stress and disease states, assessing their prospective utility as biomarkers and drug delivery vectors, offering new perspectives for tackling these challenging diseases.

Advances and Challenges of Bioassembly Strategies in Neurovascular In Vitro Modeling: An Overview of Current Technologies with a Focus on Three-Dimensional Bioprinting

Bioassembly encompasses various techniques such as bioprinting, microfluidics, organoids, and self-assembly, enabling advances in tissue engineering and regenerative medicine. Advancements in bioassembly technologies have enabled the precise arrangement and integration of various cell types to more closely mimic the complexity functionality of the neurovascular unit (NVU) and that of other biodiverse multicellular tissue structures. In this context, bioprinting offers the ability to deposit cells in a spatially controlled manner, facilitating the construction of interconnected networks. Scaffold-based assembly strategies provide structural support and guidance cues for cell growth, enabling the formation of complex bio-constructs. Self-assembly approaches utilize the inherent properties of cells to drive the spontaneous organization and interaction of neuronal and vascular components. However, recreating the intricate microarchitecture and functional characteristics of a tissue/organ poses additional challenges. Advancements in bioassembly techniques and materials hold great promise for addressing these challenges. The further refinement of bioprinting technologies, such as improved resolution and the incorporation of multiple cell types, can enhance the accuracy and complexity of the biological constructs; however, developing bioinks that support the growth of cells, viability, and functionality while maintaining compatibility with the bioassembly process remains an unmet need in the field, and further advancements in the design of bioactive and biodegradable scaffolds will aid in controlling cell adhesion, differentiation, and vascularization within the engineered tissue. Additionally, integrating advanced imaging and analytical techniques can provide real-time monitoring and characterization of bioassembly, aiding in quality control and optimization. While challenges remain, ongoing research and technological advancements propel the field forward, paving the way for transformative developments in neurovascular research and tissue engineering. This work provides an overview of the advancements, challenges, and future perspectives in bioassembly for fabricating neurovascular constructs with an add-on focus on bioprinting technologies.

Optimization of Potent, Efficacious, Selective and Blood-Brain Barrier Penetrating Inhibitors Targeting EGFR Exon20 Insertion Mutations

Herein, we report the optimization of a series of epidermal growth factor receptor (EGFR) Exon20 insertion (Ex20Ins) inhibitors using structure-based drug design (SBDD), leading to the discovery of compound 28, a potent and wild type selective molecule, which demonstrates efficacy in multiple EGFR Ex20Ins xenograft models and blood-brain barrier penetration in preclinical species. Building on our earlier discovery of an in vivo probe, SBDD was used to design a novel bicyclic core with a lower molecular weight to facilitate blood-brain barrier penetration. Further optimization including strategic linker replacement and diversification of the ring system interacting with the c-helix enabled photolytic and metabolic stability improvements. Together with refinement of molecular properties important for achieving high brain exposure, including molecular weight, H-bonding, and polarity, 28 was identified.

Ultrasound frequency-controlled microbubble dynamics in brain vessels regulate the enrichment of inflammatory pathways in the blood-brain barrier

Microbubble-enhanced ultrasound provides a noninvasive physical method to locally overcome major obstacles to the accumulation of blood-borne therapeutics in the brain, posed by the blood-brain barrier (BBB). However, due to the highly nonlinear and coupled behavior of microbubble dynamics in brain vessels, the impact of microbubble resonant effects on BBB signaling and function remains undefined. Here, combined theoretical and prospective experimental investigations reveal that microbubble resonant effects in brain capillaries can control the enrichment of inflammatory pathways that are sensitive to wall shear stress and promote differential expression of a range of transcripts in the BBB, supporting the notion that microbubble dynamics exerted mechanical stress can be used to establish molecular, in addition to spatial, therapeutic windows to target brain diseases. Consistent with these findings, a robust increase in cytotoxic T-cell accumulation in brain tumors was observed, demonstrating the functional relevance and potential clinical significance of the observed immuno-mechano-biological responses.

Utilizing Multifaceted Approaches to Target Drug Delivery in the Brain: From Nanoparticles to Biological Therapies

The blood-brain barrier (BBB) poses an important obstacle to treating neurological disorders because it limits the entry of therapeutic agents into the central nervous system (CNS). Surmounting this barrier is crucial for delivering drugs effectively and targeting precise areas of the brain affected by conditions like Parkinson's disease, Alzheimer's disease, and brain tumors. This review examines the diverse strategies employed to enhance brain targeting, including nanotechnology, viral vectors, and biological therapies. Nanoparticles, liposomes, and dendrimers offer promising approaches for encapsulating drugs and facilitating their transport across the BBB. Viral vectors, such as adeno-associated viruses, demonstrate high transfection efficiency for gene therapy applications in CNS diseases. Biological therapies, including stem cell transplantation and neuromodulation techniques, can potentially restore normal cellular function and treat genetic disorders. Challenges such as BBB permeability, safety concerns, and regulatory considerations are discussed, along with future perspectives on precision medicine, noninvasive delivery methods, and biomarker discovery. By addressing these challenges and embracing innovative approaches, the field of brain drug targeting aims to transfer the way that neurological illness is treated and improve patient outcomes.

Role of blood-brain barrier dysfunction in the development of poststroke epilepsy

Stroke is a major contributor to mortality and morbidity worldwide and the most common cause of epilepsy in the elderly in high income nations. In recent years, it has become increasingly evident that both ischemic and hemorrhagic strokes induce dysfunction of the blood-brain barrier (BBB), and that this impairment can contribute to epileptogenesis. Nevertheless, studies directly comparing BBB dysfunction and poststroke epilepsy (PSE) are largely absent. Therefore, this review summarizes the role of BBB dysfunction in the development of PSE in animal models and clinical studies. There are multiple mechanisms whereby stroke induces BBB dysfunction, including increased transcytosis, tight junction dysfunction, spreading depolarizations, astrocyte and pericyte loss, reactive astrocytosis, angiogenesis, matrix metalloproteinase activation, neuroinflammation, adenosine triphosphate depletion, oxidative stress, and finally cell death. The degree to which these effects occur is dependent on the severity of the ischemia, whereby cell death is a more prominent mechanism of BBB disruption in regions of critical ischemia. BBB dysfunction can contribute to epileptogenesis by increasing the risk of hemorrhagic transformation, increasing stroke size and the amount of cerebral vasogenic edema, extravasation of excitatory compounds, and increasing neuroinflammation. Furthermore, albumin extravasation after BBB dysfunction contributes to epileptogenesis primarily via increased transforming growth factor β signaling. Finally, seizures themselves induce BBB dysfunction, thereby contributing to epileptogenesis in a cyclical manner. In repairing this BBB dysfunction, pericyte migration via platelet-derived growth factor β signaling is indispensable and required for reconstruction of the BBB, whereby astrocytes also play a role. Although animal stroke models have their limitations, they provide valuable insights into the development of potential therapeutics designed to restore the BBB after stroke, with the ultimate goal of improving outcomes and minimizing the occurrence of PSE. In pursuit of this goal, rapamycin, statins, losartan, semaglutide, and metformin show promise, whereby modulation of pericyte migration could also be beneficial.

Advancements in strategies for overcoming the blood-brain barrier to deliver brain-targeted drugs

The blood-brain barrier is known to consist of a variety of cells and complex inter-cellular junctions that protect the vulnerable brain from neurotoxic compounds; however, it also complicates the pharmacological treatment of central nervous system disorders as most drugs are unable to penetrate the blood-brain barrier on the basis of their own structural properties. This dramatically diminished the therapeutic effect of the drug and compromised its biosafety. In response, a number of drugs are often delivered to brain lesions in invasive ways that bypass the obstruction of the blood-brain barrier, such as subdural administration, intrathecal administration, and convection-enhanced delivery. Nevertheless, these intrusive strategies introduce the risk of brain injury, limiting their clinical application. In recent years, the intensive development of nanomaterials science and the interdisciplinary convergence of medical engineering have brought light to the penetration of the blood-brain barrier for brain-targeted drugs. In this paper, we extensively discuss the limitations of the blood-brain barrier on drug delivery and non-invasive brain-targeted strategies such as nanomedicine and blood-brain barrier disruption. In the meantime, we analyze their strengths and limitations and provide outlooks on the further development of brain-targeted drug delivery systems.

Unveiling the hidden connection: the blood-brain barrier's role in epilepsy

Epilepsy is characterized by abnormal synchronous electrical activity of neurons in the brain. The blood-brain barrier, which is mainly composed of endothelial cells, pericytes, astrocytes and other cell types and is formed by connections between a variety of cells, is the key physiological structure connecting the blood and brain tissue and is critical for maintaining the microenvironment in the brain. Physiologically, the blood-brain barrier controls the microenvironment in the brain mainly by regulating the passage of various substances. Disruption of the blood-brain barrier and increased leakage of specific substances, which ultimately leading to weakened cell junctions and abnormal regulation of ion concentrations, have been observed during the development and progression of epilepsy in both clinical studies and animal models. In addition, disruption of the blood-brain barrier increases drug resistance through interference with drug trafficking mechanisms. The changes in the blood-brain barrier in epilepsy mainly affect molecular pathways associated with angiogenesis, inflammation, and oxidative stress. Further research on biomarkers is a promising direction for the development of new therapeutic strategies.

Challenges and Future Perspectives in Modeling Neurodegenerative Diseases Using Organ-on-a-Chip Technology

Neurodegenerative diseases (NDDs) affect more than 50 million people worldwide, posing a significant global health challenge as well as a high socioeconomic burden. With aging constituting one of the main risk factors for some NDDs such as Alzheimer's disease (AD) and Parkinson's disease (PD), this societal toll is expected to rise considering the predicted increase in the aging population as well as the limited progress in the development of effective therapeutics. To address the high failure rates in clinical trials, legislative changes permitting the use of alternatives to traditional pre-clinical in vivo models are implemented. In this regard, microphysiological systems (MPS) such as organ-on-a-chip (OoC) platforms constitute a promising tool, due to their ability to mimic complex and human-specific tissue niches in vitro. This review summarizes the current progress in modeling NDDs using OoC technology and discusses five critical aspects still insufficiently addressed in OoC models to date. Taking these aspects into consideration in the future MPS will advance the modeling of NDDs in vitro and increase their translational value in the clinical setting.

Minimally invasive nasal infusion (MINI) approach for CNS delivery of protein therapeutics: A case study with ovalbumin

One of the primary obstacles in treating central nervous system (CNS) disorders lies in the limited ability of disease-modifying drugs to cross the blood-brain barrier (BBB). Our previously described Minimally Invasive Nasal Depot (MIND) technique has proven successful in delivering various drugs to the brain in rat models via a trans-olfactory mucosal approach. In this study, we introduce a novel Minimally Invasive Nasal Infusion (MINI) delivery approach for administering ovalbumin, a model protein, utilizing a programmable infusion pump (iPRECIO SMP-310R) in a mouse model. This research highlights the significant role of olfactory mucosa in nose-to-brain delivery, with an efficacy of nearly 45% compared to intracerebroventricular (ICV) administration. This demonstrates its potential as an alternative procedure for treating CNS diseases, offering a greater safety profile relative to the highly invasive clinical routes traditionally adopted for CNS drug delivery.

CAR T-cell therapy: a potential treatment strategy for pediatric midline gliomas

Pediatric brain tumors are the primary cause of death in children with cancer. Diffuse midline glioma (DMG) and diffuse intrinsic pontine glioma (DIPG) are frequently unresectable due to their difficult access location, and 5-year survival remains less than 20%. Despite significant advances in tumor biology and genetics, treatment options remain limited and ineffective. Immunotherapy using T cells with a chimeric antigen receptor (CAR) that has been genetically engineered is quickly emerging as a new treatment option for these patients. High levels of expression were detected for both disialoganglioside (GD2) and B7-H3 in pediatric DMG/DIPG. Numerous studies have been conducted in recent years employing various generations of GD2-CAR T cells. The two most prevalent adverse effects found with this therapy are cytokine release syndrome, which varies in severity from mild constitutional symptoms to a high-grade disease associated with potentially fatal multi-organ failure, and neurotoxicity, known as CAR T-cell-related encephalopathy syndrome. During the acute phase of anticancer action, peri-tumoral neuro-inflammation might cause deadly hydrocephalus. The initial results of clinical trials show that the outcomes are not highly encouraging as B cell malignancies and myelomas. In vivo research on CAR T-cell therapy for DIPG has yielded encouraging results, but in human trials, the early results have shown potentially fatal side effects and very modest, but fleeting improvements. Solid tumors present a hindrance to CAR T-cell therapy because of the antigenic dilemma and the strong immune-suppressing tumor microenvironment.

Adenosine and adenosine receptors in metabolic imbalance-related neurological issues

Metabolic syndromes (e.g., obesity) are characterized by insulin resistance, chronic inflammation, impaired glucose metabolism, and dyslipidemia. Recently, patients with metabolic syndromes have experienced not only metabolic problems but also neuropathological issues, including cognitive impairment. Several studies have reported blood-brain barrier (BBB) disruption and insulin resistance in the brain of patients with obesity and diabetes. Adenosine, a purine nucleoside, is known to regulate various cellular responses (e.g., the neuroinflammatory response) by binding with adenosine receptors in the central nervous system (CNS). Adenosine has four known receptors: A1R, A2AR, A2BR, and A3R. These receptors play distinct roles in various physiological and pathological processes in the brain, including endothelial cell homeostasis, insulin sensitivity, microglial activation, lipid metabolism, immune cell infiltration, and synaptic plasticity. Here, we review the recent findings on the role of adenosine receptor-mediated signaling in neuropathological issues related to metabolic imbalance. We highlight the importance of adenosine signaling in the development of therapeutic solutions for neuropathological issues in patients with metabolic syndromes.

Blood-brain barrier alterations and their impact on Parkinson's disease pathogenesis and therapy

There is increasing evidence for blood-brain barrier (BBB) alterations in Parkinson's disease (PD), the second most common neurodegenerative disorder with rapidly rising prevalence. Altered tight junction and transporter protein levels, accumulation of α-synuclein and increase in inflammatory processes lead to extravasation of blood molecules and vessel degeneration. This could result in a self-perpetuating pathophysiology of inflammation and BBB alteration, which contribute to neurodegeneration. Toxin exposure or α-synuclein over-expression in animal models has been shown to initiate similar pathologies, providing a platform to study underlying mechanisms and therapeutic interventions. Here we provide a comprehensive review of the current knowledge on BBB alterations in PD patients and how rodent models that replicate some of these changes can be used to study disease mechanisms. Specific challenges in assessing the BBB in patients and in healthy controls are discussed. Finally, a potential role of BBB alterations in disease pathogenesis and possible implications for therapy are explored. The interference of BBB alterations with current and novel therapeutic strategies requires more attention. Brain region-specific BBB alterations could also open up novel opportunities to target specifically vulnerable neuronal subpopulations.

Upregulation of Transferrin Receptor 1 (TfR1) but Not Glucose Transporter 1 (GLUT1) or CD98hc at the Blood-Brain Barrier in Response to Valproic Acid

BACKGROUND

Transferrin receptor 1 (TfR1), glucose transporter 1 (GLUT1), and CD98hc are candidates for targeted therapy at the blood-brain barrier (BBB). Our objective was to challenge the expression of TfR1, GLUT1, and CD98hc in brain capillaries using the histone deacetylase inhibitor (HDACi) valproic acid (VPA).

METHODS

Primary mouse brain capillary endothelial cells (BCECs) and brain capillaries isolated from mice injected intraperitoneally with VPA were examined using RT-qPCR and ELISA. Targeting to the BBB was performed by injecting monoclonal anti-TfR1 (Ri7217)-conjugated gold nanoparticles measured using ICP-MS.

RESULTS

In BCECs co-cultured with glial cells, Tfrc mRNA expression was significantly higher after 6 h VPA, returning to baseline after 24 h. In vivo Glut1 mRNA expression was significantly higher in males, but not females, receiving VPA, whereas Cd98hc mRNA expression was unaffected by VPA. TfR1 increased significantly in vivo after VPA, whereas GLUT1 and CD98hc were unchanged. The uptake of anti-TfR1-conjugated nanoparticles was unaltered by VPA despite upregulated TfR expression.

CONCLUSIONS

VPA upregulates TfR1 in brain endothelium in vivo and in vitro. VPA does not increase GLUT1 and CD98hc proteins. The increase in TfR1 does not result in higher anti-TfR1 antibody targetability, suggesting targeting sufficiently occurs with available transferrin receptors without further contribution from accessory VPA-induced TfR1.

Macrophages and HLA-Class II Alleles in Multiple Sclerosis: Insights in Therapeutic Dynamics

Antigen presentation is a crucial mechanism that drives the T cell-mediated immune response and the development of Multiple Sclerosis (MS). Genetic alterations within the highly variable Major Histocompatibility Complex Class II (MHC II) have been proven to result in significant changes in the molecular basis of antigen presentation and the clinical course of patients with both Adult-Onset MS (AOMS) and Pediatric-Onset MS (POMS). Among the numerous polymorphisms of the Human Leucocyte Antigens (HLA), within MHC II complex, HLA-DRB1*15:01 has been labeled, in Caucasian ethnic groups, as a high-risk allele for MS due to the ability of its structure to increase affinity to Myelin Basic Protein (MBP) epitopes. This characteristic, among others, in the context of the trimolecular complex or immunological synapsis, provides the foundation for autoimmunity triggered by environmental or endogenous factors. As with all professional antigen presenting cells, macrophages are characterized by the expression of MHC II and are often implicated in the formation of MS lesions. Increased presence of M1 macrophages in MS patients has been associated both with progression and onset of the disease, each involving separate but similar mechanisms. In this critical narrative review, we focus on macrophages, discussing how HLA genetic alterations can promote dysregulation of this population's homeostasis in the periphery and the Central Nervous System (CNS). We also explore the potential interconnection in observed pathological macrophage mechanisms and the function of the diverse structure of HLA alleles in neurodegenerative CNS, seen in MS, by comparing available clinical with molecular data through the prism of HLA-immunogenetics. Finally, we discuss available and experimental pharmacological approaches for MS targeting the trimolecular complex that are based on cell phenotype modulation and HLA genotype involvement and try to reveal fertile ground for the potential development of novel drugs.

Cannabidiol: Pharmacodynamics and pharmacokinetic in the context of neuropsychiatric disorders

In this chapter we explored the growing interest in cannabinoids, particularly cannabidiol (CBD), over the last two decades due to their potential therapeutic applications in neurodegenerative and psychiatric disorders. CBD, a major non-psychotomimetic compound derived from Cannabis sativa, is highlighted as a safer alternative to other cannabinoids like Δ9-tetrahydrocannabinol (THC). Clinical trials have been investigating CBD formulations for conditions such as schizophrenia, multiple sclerosis, Alzheimer's, Parkinson's diseases, and stress-related disorders. However, limited access to CBD-approved formulations primarily due to their high-cost and concerns about the quality of market-available products, challenges regulatory agencies globally. The pharmacokinetics of CBD, especially after oral administration, present challenges with erratic absorption and low bioavailability. CBD's "promiscuous" pharmacodynamics involve interactions with various targets beyond the endocannabinoid system, complicating precise dosing in therapeutic interventions. This chapter delves into CBD's dose-response curves, revealing complexities that pose challenges in clinical practice. Nanobiotechnology emerges as a promising solution, with recent developments showing improved bioavailability, stability, and reduced toxicity through nanoencapsulation of CBD. While this phytocannabinoid holds immense promise in neuropsychopharmacology, we provided a comprehensive overview of the current state of CBD research and suggests potential future directions regarding the pharmacology of CBD, harnessing the benefits of this intriguing compound.

Advances in modeling permeability and selectivity of the blood-brain barrier using microfluidics

The blood-brain barrier (BBB) protects the brain by actively allowing the entry of ions and nutrients while limiting the passage of from toxins and pathogens. A healthy BBB has low permeability and high selectivity to maintain normal brain functions. Increased BBB permeability can result from neurological diseases and traumatic injuries. Modern engineering technologies such as microfluidics and fabrication techniques have advanced the development of BBB models to simulate the basic functions of BBB. However, the intrinsic BBB properties are difficult to replicate. Existing in vitro BBB models demonstrate inconsistent BBB permeability and selectivity due to variations in microfluidic design, cell types and arrangement, expression of tight junction (TJ) proteins, and use of shear stress. Specifically, microfluidic designs have flow channels of different sizes, complexity, topology, and modular structure. Different cell types are selected to mimic various physiological conditions. These factors make it challenging to compare results obtained using different experimental setups. This paper highlights key factors that play important roles in influencing microfluidic models and discusses how these factors contribute to permeability and selectivity of the BBB models.

Nongenomic ERα-AMPK Signaling Regulates Sex-Dependent Bcrp Transport Activity at the Blood-Brain Barrier

The blood-brain barrier (BBB) is an extensive capillary network that protects the brain from environmental and metabolic toxins while limiting drug delivery to the central nervous system (CNS). The ATP-binding cassette transporter breast cancer resistance protein (Bcrp) reduces drug delivery across the BBB by actively transporting its clinical substrates back into peripheral circulation before their entry into the CNS compartment. 17β-Estradiol (E2)-elicited changes in Bcrp transport activity and expression have been documented previously. We report a novel signaling mechanism by which E2 decreases Bcrp transport activity in mouse brain capillaries via rapid nongenomic signaling through estrogen receptor α. We extended this finding to investigate the effects of different endocrine-disrupting compounds (EDCs) and selective estrogen receptor modulators (SERMs) on Bcrp transport function. We also demonstrate sex-dependent expression of Bcrp and E2-sensitive Bcrp transport activity at the BBB ex vivo. This work establishes an explanted tissue-based model by which to interrogate EDCs and SERMs as modulators of nongenomic estrogenic signaling with implications for sex and hormonal regulation of therapeutic delivery into the CNS.