A blood-brain barrier overview on structure, function, impairment, and biomarkers of integrity

Camouflaging nanoreactor traverse the blood-brain barrier to catalyze redox cascade for synergistic therapy of glioblastoma

The blood-brain barrier (BBB) is a complex and highly restrictive barrier that prevents most biomolecules and drugs from entering the brain. However, effective strategies for delivering drugs to the brain are urgently needed for the treatment of glioblastoma. Based on the efficient BBB penetration properties of exosomes derived from brain metastatic breast cancer cells (EB), this work prepared a nanoreactor (denoted as MAG@EB), which was constructed by self-assembly of Mn2+, arsenate and glucose oxidase (GOx) into nanoparticles wrapped with EB. MAG@EB can enhance the efficiency of traversing the BBB, target and accumulate at in situ glioblastoma sites. The GOx-driven glycolysis effectively cuts off the glucose supply while also providing an abundance of H2O2 and lowering pH. Meanwhile, the released Mn2+ mediated Fenton-like reaction converts elevated H2O2 into highly toxic ·OH. Besides, AsV was reduced to AsIII by glutathione, and the tumor suppressor gene P53 was activated by AsIII to kill glioblastoma cells. Glioblastoma succumbed to the redox cascade triggered by MAG@EB, as the results demonstrated in vivo and in vitro, yielding a remarkable therapeutic effect. This work provides a promising therapeutic option mediated by cascaded nanoreactors for the future treatment of glioblastoma.

Mechanism of Cu entry into the brain: many unanswered questions

Brain tissue requires high amounts of copper (Cu) for its key physiological processes, such as energy production, neurotransmitter synthesis, maturation of neuropeptides, myelination, synaptic plasticity, and radical scavenging. The requirements for Cu in the brain vary depending on specific brain regions, cell types, organism age, and nutritional status. Cu imbalances cause or contribute to several life-threatening neurologic disorders including Menkes disease, Wilson disease, Alzheimer's disease, Parkinson's disease, and others. Despite the well-established role of Cu homeostasis in brain development and function, the mechanisms that govern Cu delivery to the brain are not well defined. This review summarizes available information on Cu transfer through the brain barriers and discusses issues that require further research.

LPS-induced whole-blood cytokine production and depressive symptoms in dementia spousal caregivers: The moderating effect of childhood trauma

Dementia spousal caregivers are at risk for adverse mental and physical health outcomes. Caregiver burden, anticipatory grief, and proinflammatory cytokine production may contribute to depressive symptoms among caregivers. People who report childhood trauma are more likely to have exaggerated stress responses that may also contribute to depressive symptoms in adulthood. This study aimed to test whether the relationship between whole-blood cytokine production and depressive symptoms is strongest in caregivers who report high levels of childhood trauma.

METHODS

A sample of 103 dementia spousal caregivers provided self-report data on demographics, health information, caregiver burden, anticipatory grief, and depressive symptoms. We also determined lipopolysaccharide-induced whole-blood cytokine production as the primary measure of immune cell reactivity. We measured interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10) and converted z-scores of each cytokine into a composite panel. We regressed depressive symptoms on proinflammatory cytokine production, caregiver burden, and anticipatory grief, adjusting for demographic and health-related covariates.

RESULTS

Whole-blood cytokine production and childhood trauma were associated with depressive symptoms. Childhood trauma moderated the relationship between whole-blood cytokine production and depressive symptoms. Whole-blood cytokine production was only associated with depressive symptoms at mean and high levels of childhood trauma, but not at low levels of childhood trauma. The main effects of burden and anticipatory grief on depressive symptoms were strongest for caregivers reporting high levels of childhood trauma.

DISCUSSION

Childhood trauma has lasting impacts on psychosocial experiences later in life and has effects that may confer susceptibility to inflammation-related depression. Our findings contribute to ongoing efforts to identify risk factors for adverse mental health in dementia spousal caregivers.

Carbon monoxide-releasing molecule-3 exerts neuroprotection effects after cardiac arrest in mice: A randomized controlled study

Background

Post-cardiac arrest brain injury (PCABI) is the leading cause of death in survivors of cardiac arrest (CA). Carbon monoxide-releasing molecule (CORM-3) is a water-soluble exogenous carbon monoxide that has been shown to have neuroprotection benefits in several neurological disease models. However, the effects of CORM-3 on PCABI is still unclear.

Methods

A mice model combined asystole with hemorrhage was used. Mice were anesthetized and randomized into 4 groups (n = 12/group) and underwent either 9.5 min CA followed by cardiopulmonary resuscitation (CPR) or sham surgery. CORM-3 (30 mg/kg) or vehicle (normal saline) were administered at 1 h after return of spontaneous circulation or sham surgery. Survival, neurologic deficits, alterations in the permeability of the brain-blood barrier and cerebral blood flow, changes of oxidative stress level, level of neuroinflammation and neuronal degeneration, and the activation of Nrf2/HO-1 signaling pathway were measured.

Results

In CORM-3 treated mice that underwent CA/CPR, significantly improved survival (75.00% vs. 58.33%, P = 0.0146 (24 h) and 66.67% vs. 16.67%, P < 0.0001 (72 h)) and neurological function were observed at 24 h and 72 h after ROSC (P < 0.05 for each). Additionally, increased cerebral blood flow, expression of tight junctions, and reduced reactive oxygen species generation at 24 h after ROSC were observed (P < 0.05 for each). CORM-3 treated mice had less neuron death and alleviated neuroinflammation at 72 h after ROSC (P < 0.05 for each). Notably, the Nrf2/HO-1 signaling pathway was significantly activated in mice subjected to CA/CPR with CORM-3 treatment.

Conclusions

CORM-3 could improve survival and exert neuroprotection after CA/CPR in mice. CORM-3 may be a novel and promising pharmacological therapy for PCABI.

Charge-switchable cell-penetrating peptides for rerouting nanoparticles to glioblastoma treatment

Glioblastoma (GB) is one of the most lethal types of neoplasms with unique anatomic, physiologic, and pathologic features that usually persist after exposure to standard therapeutic modalities. It is biologically aggressive, and the existence of the blood-brain barrier (BBB) limits the efficacy of standard therapies. In this work, we hypothesize the potential of surface-functionalized ultra-small nanostructured lipid carriers (usNLCs) with charge-switchable cell-penetrating peptides (CPPs) to overcome this biological barrier and improve targeted delivery to brain tumor tissues. The big question is: what is the potential of CPPs in directing nanoparticles toward brain tumor tissue? To answer this question, the usNLCs were functionalized with distinct biomolecules [five CPPs, c(RGDfK) and transferrin, Tf] through electrostatic interaction and its ability as a targeting approach to BBB (HBMEC) and glioma cells (U87 cells) evaluated in terms of physicochemical properties, cellular uptake, permeability in a 2D-BBB model, and tumor growth inhibition. Monte Carlo simulations elucidated CPP adsorption patterns. The permeability studies revealed that targeted usNLCs, especially usNLCsTf and usNLCsCPP4, exhibited an increased permeability coefficient compared to the non-targeted usNLCs. Functionalized usNLCs evidenced enhanced uptake in BBB cells, with smaller CPPs showing higher internalization (CPP1 and CPP2). Similarly, functionalized usNLCs exhibited more significant cytotoxicity in glioma cells, with specific CPPs promoting favorable internalization. Analysis of the endocytic pathway indicated that usNLCsCPPs were mainly internalized by direct translocation and caveolae-mediated endocytosis. Optimal usNLCs with dual targeting capabilities to both BBB and GB cells provide a promising therapeutic strategy for GB.

Dynamic changes in key factors of the blood-brain barrier in early diabetic mice

Chronic hyperglycemia can result in damage to the hippocampus and dysfunction of the blood-brain barrier (BBB), potentially leading to neurological disorders. This study examined the histological structure of the hippocampus and the expression of critical genes associated with the BBB at 2 early stage time points in a streptozotocin-induced diabetes mellitus (DM) mouse model. Routine histology revealed vascular congestion and dilation of Virchow-Robin spaces in the hippocampal CA1 region of the DM group. Neuronal alterations included rounding and swelling and reduction in Nissl bodies and increased apoptosis. Compared to the control group, TJP1 mRNA expression in the DM group was significantly lower (P < .05 or P < .01), while mRNA levels of JAM3, TJP3, CLDN5, CLDN3, and OCLN initially increased and then decreased. At 7, 14, and 21 days, mRNA levels of the receptor for advanced glycation end products (AGER) were greater in the DM group than in the control group (P < .05 or P < .01). These findings indicate that early-stage diabetes may cause structural and functional impairments in hippocampal CA1 in mice. These abnormalities may parallel alterations in the expression of key BBB tight junction molecules and elevated AGER expression in early DM patients.

Quantification of oxidative stress markers in the blood sera following subacute administration of different oximes in rats

Oxidative stress status, as a disruption of redox homeostasis, in the blood sera of Wistar rats caused by repeated application of selected acetylcholinesterase reactivators - asoxime, obidoxime, K027, K048, K074, and K075 were evaluated. Throughout this study, each oxime in a dose of 0.1 of LD50/kg im was given 2x/week for 4 weeks. Then, seven days after the last oximes' application, markers of lipid peroxidation (malondialdehyde, MDA), and protein oxidation (advanced oxidation protein products, AOPP), as well as the activity of antioxidant enzymes (catalase, CAT, superoxide dismutase, SOD, reduced glutathione, GSH, and oxidized glutathione, GSSG), were determined. Oxidative stress parameters, MDA and AOPP were significantly highest in the K048-, K074- and K075-treated groups (p < 0.001). The activity of CAT was significantly elevated in the obidoxime-treated group (p < 0.05), while treatment with K027, K048, and K074 induced high elevation in SOD levels (p < 0.01, p < 0.001). Interestingly, the activity of GSH in each oxime-treated group was significantly elevated. Unlike, treatment with obidoxime caused elevation in GSSG levels (p < 0.01). As a continuation of our previously published data, these results assure that applied oximes following subacute treatment ameliorated the oxidative status and further adverse systemic toxic effects in rats.

Insect-derived extracts and peptides in neuroprotection

Throughout history, various cultures have recognized the significance of insects and have integrated them into traditional medicinal practices. In addition to medicines, insects are garnering attention as a sustainable and nutritious dietary alternative. Although edible insects have long been recognized as food sources in many Asian cultures, recent scientific studies have highlighted their potential therapeutic benefits, particularly in the field of neuroprotection. This review explores insect-derived extracts and peptides, elucidating their neuroprotective potential. This review highlights the potential use of insects as a source of neuroprotective agents. Advancements in neuroprotection may find a key ally in insects as our understanding of the symbiotic relationship between insects and human health becomes more profound.

Navigating the neurological frontier: Macromolecular marvels in overcoming blood-brain barrier challenges for advanced drug delivery

The blood-brain interface poses formidable obstacles in addressing neurological conditions such as Alzheimer's, Multiple Sclerosis, brain cancers, and cerebrovascular accidents. Serving as a safeguard against potential threats in the blood, this barrier hinders direct drug delivery to affected cells, necessitating specialized transport mechanisms. Within the realm of nanotechnology, the creation of nanoscale carriers, including macromolecules such as polymers, lipids, and metallic nanoparticles, is gaining prominence. These carriers, tailored in diverse forms and sizes and enriched with specific functional groups for enhanced penetration and targeting, are capturing growing interest. This revised abstract explores the macromolecular dimension in understanding how nanoparticles interact with the blood-brain barrier. It re-evaluates the structure and function of the blood-brain barrier, highlighting macromolecular nanocarriers utilized in drug delivery to the brain. The discussion delves into the intricate pathways through which drugs navigate the blood-brain barrier, emphasizing the distinctive attributes of macromolecular nanocarriers. Additionally, it explores recent innovations in nanotechnology and unconventional approaches to drug delivery. Ultimately, the paper addresses the intricacies and considerations in developing macromolecular-based nanomedicines for the brain, aiming to advance the creation and evolution of nanomedicines for neurological ailments.

Advancing glioblastoma treatment through iron metabolism: A focus on TfR1 and Ferroptosis innovations

Glioblastoma (GBM) represents a formidable challenge in oncology, characterized by aggressive proliferation and poor prognosis. Iron metabolism plays a critical player in GBM progression, with dysregulated iron uptake and utilization contributing to tumor growth and therapeutic resistance. Iron's pivotal role in DNA synthesis, oxidative stress, and angiogenesis underscores its significance in GBM pathogenesis. Elevated expression of iron transporters, such as transferrin receptor 1 (TfR1), highlights the tumor's reliance on iron for survival. Innovative treatment strategies targeting iron dysregulation hold promise for overcoming therapeutic challenges in GBM management. Approaches such as iron chelation therapies, induction of ferroptosis to nanoparticle-based drug delivery systems exploit iron-dependent vulnerabilities, offering avenues for enhance treatment efficacy and improve patient outcomes. As research advances, understanding the complexities of iron-mediated carcinogenesis provides a foundation for developing precision medicine approaches tailored to combat GBM effectively. This review explores the intricate relationship between iron metabolism and GBM, elucidating its multifaceted implications and therapeutic opportunities. By consolidating the latest insights into iron metabolism in GBM, this review underscores its potential as a therapeutic target for improving patient care in combination with the standard of care approach.

Postmortem biochemistry of GFAP, NSE and S100B in cerebrospinal fluid and in vitreous humor for estimation of postmortem interval: a pilot study

Postmortem interval (PMI) is a challenging issue in forensic practice. Although postmortem biomarkers of traumatic brain injury (TBI) are recognised as an emerging resource for PMI estimation, their role remains controversial. This study aims to evaluate postmortem concentrations of three TBI biomarkers (GFAP, NSE and S100B) in two matrices (cerebrospinal fluid and vitreous humor), in order to find out if these markers could be adopted in PMI estimation. Thirty-five deceased individuals with known PMI who underwent forensic autopsy at the University of Parma were examined. Matrices were collected during autopsy, then biomarker concentrations were determined through the enzyme-linked immunosorbent assay. Statistical significance of the data in relation to PMI was studied. The correlation of biomarkers with PMI, examined with samples divided into six groups according to the number of days elapsed since death, was not statistically significant, although S100B in cerebrospinal fluid showed an increasing trend in cases from 1 to 5 days of PMI. Comparison between cases with 1 day of PMI and those with 2 or more days of PMI showed a statistically significant correlation for GFAP and NSE in cerebrospinal fluid. GFAP and NSE in cerebrospinal fluid represent appropriate biomarkers in PMI estimation to distinguish cases with one day of PMI from those with two or more days of PMI. The current study was limited by the scarcity of the cohort and the narrow spectrum of cases. Further research is needed to confirm these observations.

Microneedle-mediated drug delivery for neurological diseases

Neurological disorders, including brain injury, brain tumors, and neurodegenerative diseases, rank as the second leading cause of death worldwide. Exploring effective new treatments for neurological disorders has long been a hot research issue in clinical practice. Recently, microneedles (MNs) have attracted much attention due to their designation as a "painless and non-invasive" novel transdermal delivery method, characterized by their biocompatibility and sustainability. The advantages of MNs open an avenue for potential therapeutic interventions targeting neurological disorders. This review presents a concise overview of progress in the field of MNs, with highlights on the application in the treatment of neurological disorders. Notably, trends in the development of MNs and future challenges are also discussed.

The significance of upper glycolytic components in regulating retinal pigment epithelial cellular behavior

Cell adhesion to the extracellular matrix and its natural outcome of cell spreading, along with the maintenance of barrier activity, are essential behaviors of epithelial cells, including retinal pigment epithelium (RPE). Disruptions in these characteristics can result in severe vision-threatening diseases such as diabetic macular edema and age-related macular degeneration. However, the precise mechanisms underlying how RPE cells regulate their barrier integrity and cell spreading are not fully understood. This study aims to elucidate the relative importance of upper glycolytic components in governing these cellular behaviors of RPE cells. Electric Cell-Substrate Impedance Sensing (ECIS) technology was utilized to assess in real-time the effects of targeting various upper glycolytic enzymes on RPE barrier function and cell spreading by measuring cell resistance and capacitance, respectively. Specific inhibitors used included WZB117 for Glut1 inhibition, Lonidamine for Hexokinase inhibition, PFK158 for PFKFB3/PFK axis inhibition, and TDZD-8 for Aldolase inhibition. Additionally, the viability of RPE cells was evaluated using a lactate dehydrogenase (LDH) cytotoxicity assay. The most significant decrease in electrical resistance and increase in capacitance of RPE cells were observed due to dose-dependent inhibition of Glut1 using WZB117, as well as Aldolase inhibition with TDZD-8. LDH level analysis at 24-72 h post-treatment with WZB117 (1 and 10 μM) or TDZD-8 (1 μM) showed no significant difference compared to the control, indicating that the disruption of RPE functionality was not attributed to cell death. Lastly, inhibition of other upper glycolytic components, including PFKFB3/PFK with PFK158 or Hexokinase with Lonidamine, did not significantly affect RPE cell behavior. This study provides insights into the varied roles of upper glycolytic components in regulating the functionality of RPE cells. Specifically, it highlights the critical roles of Glut1 and Aldolase in preserving barrier integrity and promoting RPE cell adhesion and spreading. Such understanding will guide the development of safe interventions to treat RPE cell dysfunction in various retinal disorders.

Melatonin: A potential nighttime guardian against Alzheimer's

In the context of the escalating global health challenge posed by Alzheimer's disease (AD), this comprehensive review considers the potential of melatonin in both preventive and therapeutic capacities. As a naturally occurring hormone and robust antioxidant, accumulating evidence suggests melatonin is a compelling candidate to consider in the context of AD-related pathologies. The review considers several mechanisms, including potential effects on amyloid-beta and pathologic tau burden, antioxidant defense, immune modulation, and regulation of circadian rhythms. Despite its promise, several gaps need to be addressed prior to clinical translation. These include conducting additional randomized clinical trials in patients with or at risk for AD dementia, determining optimal dosage and timing, and further determining potential side effects, particularly of long-term use. This review consolidates existing knowledge, identifies gaps, and suggests directions for future research to better understand the potential of melatonin for neuroprotection and disease mitigation within the landscape of AD.

Maternal n-3 enriched diet reprograms the offspring neurovascular transcriptome and blunts inflammation induced by endotoxin in the neonate

Infection during the perinatal period can adversely affect brain development, predispose infants to ischemic stroke and have lifelong consequences. We previously demonstrated that diet enriched in n-3 polyunsaturated fatty acids (n-3 PUFA) transforms brain lipid composition in the offspring and protects the neonatal brain from stroke, in part by blunting injurious immune responses. Critical to the interface between the brain and systemic circulation is the vasculature, endothelial cells in particular, that support brain homeostasis and provide a barrier to systemic infection. Here, we examined whether maternal PUFA-enriched diets exert reprograming of endothelial cell signalling in postnatal day 9 mice after modeling aspects of infection using LPS. Transcriptome analysis was performed on microvessels isolated from brains of pups from dams maintained on 3 different maternal diets from gestation day 1: standard, n-3 enriched or n-6 enriched diets. Depending on the diet, in endothelial cells LPS produced distinct regulation of pathways related to immune response, cell cycle, extracellular matrix, and angiogenesis. N-3 PUFA diet enabled higher immune reactivity in brain vasculature, while preventing imbalance of cell cycle regulation and extracellular matrix cascades that accompanied inflammatory response in standard diet. Cytokine analysis revealed a blunted LPS response in blood and brain of offspring from dams on n-3 enriched diet. Analysis of cerebral vasculature in offspring in vivo revealed no differences in vessel density. However, vessel complexity was decreased in response to LPS at 72 h in standard and n-6 diets. Thus, LPS modulates specific transcriptomic changes in brain vessels of offspring rather than major structural vessel characteristics during early life. N-3 PUFA-enriched maternal diet in part prevents an imbalance in homeostatic processes, alters inflammation and ultimately mitigates changes to the complexity of surface vessel networks that result from infection. Importantly, maternal diet may presage offspring neurovascular outcomes later in life.

Harnessing cells to improve transport of nanomedicines

Efficient tumour treatment is hampered by the poor selectivity of anticancer drugs, resulting in scarce tumour accumulation and undesired off-target effects. Nano-sized drug-delivery systems in the form of nanoparticles (NPs) have been proposed to improve drug distribution to solid tumours, by virtue of their ability of passive and active tumour targeting. Despite these advantages, literature studies indicated that less than 1% of the administered NPs can successfully reach the tumour mass, highlighting the necessity for more efficient drug transporters in cancer treatment. Living cells, such as blood cells, circulating immune cells, platelets, and stem cells, are often found as an infiltrating component in most solid tumours, because of their ability to naturally circumvent immune recognition, bypass biological barriers, and reach inaccessible tissues through innate tropism and active motility. Therefore, the tumour-homing ability of these cells can be harnessed to design living cell carriers able to improve the transport of drugs and NPs to tumours. Albeit promising, this approach is still in its beginnings and suffers from difficult scalability, high cost, and poor reproducibility. In this review, we present an overview of the most common cell transporters of drugs and NPs, and we discuss how different cell types interact with biological barriers to deliver cargoes of various natures to tumours. Finally, we analyse the different techniques used to load drugs or NPs in living cells and discuss their advantages and disadvantages.

Senescence-associated microvascular endothelial dysfunction: A focus on the blood-brain and blood-retinal barriers

The blood-brain barrier (BBB) and blood-retinal barrier (BRB) constitute critical physiochemical interfaces, precisely orchestrating the bidirectional communication between the brain/retina and blood. Increased permeability or leakage of these barriers has been demonstrably linked to age-related vascular and parenchymal damage. While it has been suggested that the gradual aging process may coincide with disruptions in these barriers, this phenomenon is significantly exacerbated in individuals with age-related neurodegenerative disorders (ARND). This review focuses on the microvascular endothelium, a key constituent of BBB and BRB, highlighting the impact of endothelial senescence on barrier dysfunction and exploring recent discoveries regarding core pathways implicated in its breakdown. Subsequently, we address the "vascular senescence hypothesis" for ARND, with a particular emphasis on Alzheimer's disease and age-related macular degeneration, centered on endothelial senescence. Finally, we discuss potential senotherapeutic strategies targeting barrier dysfunction.

Recent Insights into the Neurobiology of Alzheimer's Disease and Advanced Treatment Strategies

In recent years, significant advancements have been made in understanding Alzheimer's disease from both neurobiological and clinical perspectives. Exploring the complex systems underlying AD has unveiled insights that could potentially revolutionize therapeutic approaches. Recent investigations have highlighted intricate interactions among genetic, molecular, and environmental factors in AD. Optimism arises from neurobiological advancements and diverse treatment options, potentially slowing or halting disease progression. Amyloid-beta plaques and tau protein tangles crucially influence AD onset and progression. Emerging treatments involve diverse strategies, such as approaches targeting multiple pathways involved in AD pathogenesis, such as inflammation, oxidative stress, and synaptic dysfunction pathways. Clinical trials using humanized monoclonal antibodies, focusing on immunotherapies eliminating amyloid-beta, have shown promise. Nonpharmacological interventions such as light therapy, electrical stimulation, cognitive training, physical activity, and dietary changes have drawn attention for their potential to slow cognitive aging and enhance brain health. Precision medicine, which involves tailoring therapies to individual genetic and molecular profiles, has gained traction. Ongoing research and interdisciplinary collaboration are expected to yield more effective treatments.

Small Scale, Big Impact: Nanotechnology-Enhanced Drug Delivery for Brain Diseases

Central nervous system (CNS) diseases, ranging from brain cancers to neurodegenerative disorders like dementia and acute conditions such as strokes, have been heavily burdening healthcare and have a direct impact on patient quality of life. A significant hurdle in developing effective treatments is the presence of the blood-brain barrier (BBB), a highly selective barrier that prevents most drugs from reaching the brain. The tight junctions and adherens junctions between the endothelial cells and various receptors expressed on the cells make the BBB form a nonfenestrated and highly selective structure that is crucial for brain homeostasis but complicates drug delivery. Nanotechnology offers a novel pathway to circumvent this barrier, with nanoparticles engineered to ferry drugs across the BBB, protect drugs from degradation, and deliver medications to the designated area. After years of development, nanoparticle optimization, including sizes, shapes, surface modifications, and targeting ligands, can enable nanomaterials tailored to specific brain drug delivery settings. Moreover, smart nano drug delivery systems can respond to endogenous and exogenous stimuli that control subsequent drug release. Here, we address the importance of the BBB in brain disease treatment, summarize different delivery routes for brain drug delivery, discuss the cutting-edge nanotechnology-based strategies for brain drug delivery, and further offer valuable insights into how these innovations in nanoparticle technology could revolutionize the treatment of CNS diseases, presenting a promising avenue for noninvasive, targeted therapeutic interventions.

Alteration in early resting‑state functional MRI activity in comatose survivors of cardiac arrest: a prospective cohort study

BACKGROUND

This study aimed to explore the characteristics of abnormal regional resting-state functional magnetic resonance imaging (rs-fMRI) activity in comatose patients in the early period after cardiac arrest (CA), and to investigate their relationships with neurological outcomes. We also explored the correlations between jugular venous oxygen saturation (SjvO2) and rs-fMRI activity in resuscitated comatose patients. We also examined the relationship between the amplitude of the N20-baseline and the rs-fMRI activity within the intracranial conduction pathway of somatosensory evoked potentials (SSEPs).

METHODS

Between January 2021 and January 2024, eligible post-resuscitated patients were screened to undergo fMRI examination. The amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), and regional homogeneity (ReHo) of rs-fMRI blood oxygenation level-dependent (BOLD) signals were used to characterize regional neural activity. Neurological outcomes were evaluated using the Glasgow-Pittsburgh cerebral performance category (CPC) scale at 3 months after CA.

RESULTS

In total, 20 healthy controls and 31 post-resuscitated patients were enrolled in this study. The rs-fMRI activity of resuscitated patients revealed complex changes, characterized by increased activity in some local brain regions and reduced activity in others compared to healthy controls (P < 0.05). However, the mean ALFF values of the whole brain were significantly greater in CA patients (P = 0.011). Among the clusters of abnormal rs-fMRI activity, the cluster values of ALFF in the left middle temporal gyrus and inferior temporal gyrus and the cluster values of ReHo in the right precentral gyrus, superior frontal gyrus and middle frontal gyrus were strongly correlated with the CPC score (P < 0.001). There was a strong correlation between the mean ALFF and SjvO2 in CA patients (r = 0.910, P < 0.001). The SSEP N20-baseline amplitudes in CA patients were negatively correlated with thalamic rs-fMRI activity (all P < 0.001).

CONCLUSIONS

This study revealed that abnormal rs-fMRI BOLD signals in resuscitated patients showed complex changes, characterized by increased activity in some local brain regions and reduced activity in others. Abnormal BOLD signals were associated with neurological outcomes in resuscitated patients. The mean ALFF values of the whole brain were closely related to SjvO2 levels, and changes in the thalamic BOLD signals correlated with the N20-baseline amplitudes of SSEP responses.

TRIAL REGISTRATION

NCT05966389 (Registered July 27, 2023).

Central nervous system metastases in advanced non-small cell lung cancer: A review of the therapeutic landscape

Up to 40% of patients with non-small cell lung cancer (NSCLC) develop central nervous system (CNS) metastases. Current treatments for this subgroup of patients with advanced NSCLC include local therapies (surgery, stereotactic radiosurgery, and, less frequently, whole-brain radiotherapy), targeted therapies for oncogene-addicted NSCLC (small molecules, such as tyrosine kinase inhibitors, and antibody-drug conjugates), and immune checkpoint inhibitors (as monotherapy or combination therapy), with multiple new drugs in development. However, confirming the intracranial activity of these treatments has proven to be challenging, given that most lung cancer clinical trials exclude patients with untreated and/or progressing CNS metastases, or do not include prespecified CNS-related endpoints. Here we review progress in the treatment of patients with CNS metastases originating from NSCLC, examining local treatment options, systemic therapies, and multimodal therapeutic strategies. We also consider challenges regarding assessment of treatment response and provide thoughts around future directions for managing CNS disease in patients with advanced NSCLC.

Systemic Brain Delivery of Oligonucleotide Therapeutics Enhanced by Protein Corona-Assisted DNA Cubes

The systemic delivery of oligonucleotide therapeutics to the brain is challenging but highly desirable for the treatment of brain diseases undruggable with traditional small-molecule drugs. In this study, a set of DNA nanostructures is prepared and screened them to develop a protein corona-assisted platform for the brain delivery of oligonucleotide therapeutics. The biodistribution analysis of intravenously injected DNA nanostructures reveals that a cube-shaped DNA nanostructure (D-Cb) can penetrate the brain-blood barrier (BBB) and reach the brain tissue. The brain distribution level of D-Cb is comparable to that of other previous nanoparticles conjugated with brain-targeting ligands. Proteomic analysis of the protein corona formed on D-Cb suggests that its brain distribution is driven by endothelial receptor-targeting ligands in the protein corona, which mediate transcytosis for crossing the BBB. D-Cb is subsequently used to deliver an antisense oligonucleotide (ASO) to treat glioblastoma multiforme (GBM) in mice. While free ASO is unable to reach the brain, ASO loaded onto D-Cb is delivered efficiently to the brain tumor region, where it downregulates the target gene and exerts an anti-tumor effect on GBM. D-Cb is expected to serve as a viable platform based on protein corona formation for systemic brain delivery of oligonucleotide therapeutics.

Poliovirus capsid protein VP3 can penetrate vascular endothelial cells

The poliovirus (PV) enters the central nervous system (CNS) via the bloodstream, suggesting the existence of a mechanism to cross the blood-brain barrier. Here, we report that PV capsid proteins (VP1 and VP3) can penetrate cells, with VP3 being more invasive. Two independent parts of VP3 are responsible for this function. Both peptides can penetrate human umbilical cord vascular endothelial cells, and one peptide of VP3 could also penetrate peripheral blood mononuclear cells. In an in vitro blood-brain barrier model using rat-derived astrocytes, pericytes, and endothelial cells, both peptides were observed to traverse from the blood side to the brain side at 6 h after administration. These results provide insights into the molecular mechanisms underlying PV invasion into the CNS.

Dysregulation of Ion Channels and Transporters and Blood-Brain Barrier Dysfunction in Alzheimer's Disease and Vascular Dementia

The blood-brain barrier (BBB) plays a critical role in maintaining ion and fluid homeostasis, essential for brain metabolism and neuronal function. Regulation of nutrient, water, and ion transport across the BBB is tightly controlled by specialized ion transporters and channels located within its unique cellular components. These dynamic transport processes not only influence the BBB's structure but also impact vital signaling mechanisms, essential for its optimal function. Disruption in ion, pH, and fluid balance at the BBB is associated with brain pathology and has been implicated in various neurological conditions, including stroke, epilepsy, trauma, and neurodegenerative diseases such as Alzheimer's disease (AD). However, knowledge gaps exist regarding the impact of ion transport dysregulation on BBB function in neurodegenerative dementias. Several factors contribute to this gap: the complex nature of these conditions, historical research focus on neuronal mechanisms and technical challenges in studying the ion transport mechanisms in in vivo models and the lack of efficient in vitro BBB dementia models. This review provides an overview of current research on the roles of ion transporters and channels at the BBB and poses specific research questions: 1) How are the expression and activity of key ion transporters altered in AD and vascular dementia (VaD); 2) Do these changes contribute to BBB dysfunction and disease progression; and 3) Can restoring ion transport function mitigate BBB dysfunction and improve clinical outcomes. Addressing these gaps will provide a greater insight into the vascular pathology of neurodegenerative disorders.

Association of APOE genotype with blood-brain barrier permeability in neurodegenerative disorders

Apolipoprotein E (APOE) is recognized for its role in modulating blood-brain barrier (BBB) permeability in vitro, which may have significant implications for the pathogenesis and progression of neurodegenerative disorders. However, evidence in vivo is contrasting. This study explores the impact of APOE genotypes on BBB integrity among 230 participants experiencing cognitive impairment, encompassing cases of Alzheimer's disease (AD) as well as various non-AD neurodegenerative conditions. To assess BBB integrity, we utilized cerebrospinal fluid (CSF)/serum albumin ratios and CSF/serum kappa and lambda free light chains (FLCs) as indirect markers. Our findings show a dose-dependent increase in BBB permeability in individuals carrying the APOE ε4 allele, marked by elevated CSF/serum albumin and FLCs ratios, with this trend being especially pronounced in AD patients. These results highlight the association of APOE ε4 with BBB permeability, providing valuable insights into the pathophysiology of neurodegenerative diseases.

3,3',4,5'-Tetramethoxy-trans-stilbene and 3,4',5-trimethoxy-trans-stilbene prevent oxygen-glucose deprivation-induced injury in brain endothelial cell

Blood-brain barrier (BBB) disruption is a major pathophysiological event of ischemic stroke. Brain microvascular endothelial cells are critical to maintain homeostasis between central nervous system and periphery. Resveratrol protects against ischemic stroke. 3,3',4,5'-tetramethoxy-trans-stilbene (3,3',4,5'-TMS) and 3,4',5-trimethoxy-trans-stilbene (3,4',5-TMS) are resveratrol derivatives with addition of methoxy groups, showing better pharmacokinetic performance. We aimed to explore their protective effects and underlying mechanisms. Oxygen-glucose deprivation (OGD) model was applied in bEnd.3 cell line, mouse brain microvascular endothelium to mimic ischemia. The cells were pre-treated with 3,3',4,5'-TMS or 3,4',5-TMS (1 and 5 μM, 24 h) and then subjected to 2-h OGD injury. Cell viability, levels of proinflammatory cytokines and reactive oxygen species (ROS), and protein expressions were measured by molecular assays and fluorescence staining. OGD injury triggered cell death, inflammatory responses, ROS production and nuclear factor-kappa B (NF-κB) signalling pathway. These impairments were remarkably attenuated by the two stilbenes, 3,3',4,5'-TMS and 3,4',5-TMS. They also alleviated endothelial barrier injuries through upregulating the expression of tight junction proteins. Moreover, 3,3',4,5'-TMS and 3,4',5-TMS activated 5' adenosine monophosphate-activated protein kinase (AMPK) and endothelial nitric oxide synthase (eNOS). Overall, 3,3',4,5'-TMS and 3,4',5-TMS exert protective effects against OGD damage through suppressing cell death, inflammatory responses, oxidative stress, as well as BBB disruption on bEnd.3 cells.

Microphysiological Blood-Brain Barrier Systems for Disease Modeling and Drug Development

The blood-brain barrier (BBB) is a highly controlled microenvironment that regulates the interactions between cerebral blood and brain tissue. Due to its selectivity, many therapeutics targeting various neurological disorders are not able to penetrate into brain tissue. Pre-clinical studies using animals and other in vitro platforms have not shown the ability to fully replicate the human BBB leading to the failure of a majority of therapeutics in clinical trials. However, recent innovations in vitro and ex vivo modeling called organs-on-chips have shown the potential to create more accurate disease models for improved drug development. These microfluidic platforms induce physiological stressors on cultured cells and are able to generate more physiologically accurate BBBs compared to previous in vitro models. In this review, different approaches to create BBBs-on-chips are explored alongside their application in modeling various neurological disorders and potential therapeutic efficacy. Additionally, organs-on-chips use in BBB drug delivery studies is discussed, and advances in linking brain organs-on-chips onto multiorgan platforms to mimic organ crosstalk are reviewed.

Exploiting Metabolic Defects in Glioma with Nanoparticle-Encapsulated NAMPT Inhibitors

The treatment of primary central nervous system tumors is challenging due to the blood-brain barrier and complex mutational profiles, which is associated with low survival rates. However, recent studies have identified common mutations in gliomas [isocitrate dehydrogenase (IDH)-wild-type and mutant, WHO grades II-IV; with grade IV tumors referred to as glioblastomas (GBM)]. These mutations drive epigenetic changes, leading to promoter methylation at the nicotinic acid phosphoribosyl transferase (NAPRT) gene locus, which encodes an enzyme involved in generating NAD+. Importantly, NAPRT silencing introduces a therapeutic vulnerability to inhibitors targeting another NAD+ biogenesis enzyme, nicotinamide phosphoribosyl transferase (NAMPT), rationalizing a treatment for these malignancies. Multiple systemically administered NAMPT inhibitors (NAMPTi) have been developed and tested in clinical trials, but dose-limiting toxicities-including bone marrow suppression and retinal toxicity-have limited their efficacy. Here, we report a novel approach for the treatment of NAPRT-silenced GBMs using nanoparticle (NP)-encapsulated NAMPTis administered by convection-enhanced delivery (CED). We demonstrate that GMX1778 (a NAMPTi) can be formulated in degradable polymer NPs with retention of potency for NAMPT inhibition and anticancer activity in vitro, plus sustained drug release in vitro and in vivo. Direct injection of these drugs via CED into the brain is associated with reduced retinal toxicity compared with systemic administration. Finally, we show that CED of NP-encapsulated GMX1778 to NAPRT-silenced intracranial GBM xenografts in mice exhibit significant tumor growth delay and extends survival. These data support an approach to treat gliomas harboring defects in NAD+ metabolism using CED of NP-encapsulated NAMPTis to greatly improve the therapeutic index and treatment efficacy for this class of drugs.

Abnormal Cerebrovascular Activity, Perfusion, and Glymphatic Clearance in Lewy Body Diseases

Cerebrovascular activity is not only crucial to optimal cerebral perfusion, but also plays an important role in the glymphatic clearance of interstitial waste, including α-synuclein. This highlights a need to evaluate how cerebrovascular activity is altered in Lewy body diseases. This review begins by discussing how vascular risk factors and cardiovascular autonomic dysfunction may serve as upstream or direct influences on cerebrovascular activity. We then discuss how patients with Lewy body disease exhibit reduced and delayed cerebrovascular activity, hypoperfusion, and reductions in measures used to capture cerebrospinal fluid flow, suggestive of a reduced capacity for glymphatic clearance. Given the lack of an existing framework, we propose a model by which these processes may foster α-synuclein aggregation and neuroinflammation. Importantly, this review highlights several avenues for future research that may lead to treatments early in the disease course, prior to neurodegeneration. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

COVID-19 and Long COVID: Disruption of the Neurovascular Unit, Blood-Brain Barrier, and Tight Junctions

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), could affect brain structure and function. SARS-CoV-2 can enter the brain through different routes, including the olfactory, trigeminal, and vagus nerves, and through blood and immunocytes. SARS-CoV-2 may also enter the brain from the peripheral blood through a disrupted blood-brain barrier (BBB). The neurovascular unit in the brain, composed of neurons, astrocytes, endothelial cells, and pericytes, protects brain parenchyma by regulating the entry of substances from the blood. The endothelial cells, pericytes, and astrocytes highly express angiotensin converting enzyme 2 (ACE2), indicating that the BBB can be disturbed by SARS-CoV-2 and lead to derangements of tight junction and adherens junction proteins. This leads to increased BBB permeability, leakage of blood components, and movement of immune cells into the brain parenchyma. SARS-CoV-2 may also cross microvascular endothelial cells through an ACE2 receptor-associated pathway. The exact mechanism of BBB dysregulation in COVID-19/neuro-COVID is not clearly known, nor is the development of long COVID. Various blood biomarkers could indicate disease severity and neurologic complications in COVID-19 and help objectively diagnose those developing long COVID. This review highlights the importance of neurovascular and BBB disruption, as well as some potentially useful biomarkers in COVID-19, and long COVID/neuro-COVID.

Propofol Suppresses LPS-induced BBB Damage by Regulating miR-130a-5p/ZO-1 Axis

The blood-brain barrier (BBB) is a highly selective semi-permeable barrier that separates circulating blood from the extracellular fluid of the brain and central nervous system, which is crucial for maintaining brain homeostasis. This study aimed to explore the role of propofol in BBB damage and further evaluate the underlying molecular mechanism. Lipopolysaccharide (LPS) was administered to mice to create an in vivo BBB damage mice model. Additionally, hCMEC/D3 cells as brain microvascular endothelial cells (BMECs) were treated with LPS to establish the in vitro BBB damage cell model. Subsequently, propofol was used for the BBB damage model. Evans blue staining and fluorescein sodium were utilized in the in vivo experiments to demonstrate BBB leakage and BBB permeability. Cell counting kit-8 (CCK-8) assay was used to assess cell viability and the trans-endothelial electrical resistance (TEER) value was measured using an epithelial voltmeter. Furthermore, enzyme-linked immunosorbent assay was performed to measure the levels of the inflammatory cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). The levels of miR-130a-5p and zonula occludens-1 (ZO-1) in brain tissues and cells were detected using reverse transcription-quantitative polymerase chain reaction, western blot, or immunofluorescence staining. Furthermore, a dual-luciferase reporter assay was used to demonstrate the association between miR-130a-5p and ZO-1. Propofol treatment suppressed BBB leakage, the amount of fluorescein sodium, and the levels of IL-1β and TNF-α in the LPS-induced BBB damage mice model. Meanwhile, propofol treatment increased the TEER value in the LPS-induced hCMEC/D3 cells. Additionally, propofol treatment significantly down-regulated miR-130a-5p and up-regulated ZO-1. More importantly, miR-130a-5p directly targeted ZO-1 and negatively regulated ZO-1 expression in hCMEC/D3 cells. Furthermore, miR-130a-5p mimic partially reversed the effect of propofol on the TEER value and the levels of inflammatory cytokines such as IL-1β and TNF-α in the LPS-induced hCMEC/D3 cells. Propofol suppressed LPS-induced BBB damage by regulating miR-130a-5p/ZO-1 axis. These findings suggested a potentially effective treatment approach for BBB damage.

Blood brain barrier dysfunction in healthy aging and dementia: Why, how, what for?

The blood brain barrier (BBB) is an indispensable structure that maintains the central nervous system (CNS) microenvironment for a correct neuronal function. It is composed by highly specialized microvessels, surrounded by astrocytes, pericytes, neurons and microglia cells, which tightly control the influx and efflux of substances to the brain parenchyma. During aging, the BBB becomes impaired, and it may contribute to the development of neurodegenerative and neurological disorders including Alzheimer's disease and other dementias. Restoring the BBB can be a strategy to prevent disease onset and development, reducing the symptoms of these conditions. This work critically reviews the major mechanisms underlying BBB breakdown in healthy and unhealthy aging, as well as biomarkers and methodologies that accurately assess its impairment. Complementarily, potential therapeutic targets are discussed as new strategies to restore the normal function of the BBB in aging.

Comparative in silico analysis of CNS-active molecules targeting the blood-brain barrier choline transporter for Alzheimer's disease therapy

This study investigated the blood‒brain barrier (BBB) permeability of the central nervous system (CNS)-active compounds donepezil (DON), methionine (MET), and memantine (MEM) by employing a comprehensive in silico approach. These compounds are of particular interest for Alzheimer's disease (AD) therapy. Rigid-flexible molecular docking simulations indicated favorable binding affinities of all the compounds with BBB-ChT, with DON exhibiting the highest binding affinity (ΔGbind = -10.26 kcal/mol), predominantly mediated by significant hydrophobic interactions. In silico kinetic profiling suggested the stability of the DON/BBB-ChT complex, with ligand release prompted by conformational changes. 3D molecular alignment corroborated a minor conformational shift for DON in its minimal binding energy pose. Predictions indicated that active transport mechanisms notably enhance the brain distribution of donepezil compared to that of MET and MEM. Additionally, DON and MEM exhibited low mutagenic probabilities, while MET was identified as highly mutagenic. Overall, these findings highlight the potential of donepezil for superior BBB penetration, primarily through active transport mechanisms, underscoring the need for further validation through in vitro and in vivo studies for effective AD treatment.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00245-w.

Proteomic Profiling Reveals Age-Related Changes in Transporter Proteins in the Human Blood-Brain Barrier

The Blood-Brain Barrier (BBB) is a crucial, selective barrier that regulates the entry of molecules including nutrients, environmental toxins, and therapeutic medications into the brain. This function relies heavily on brain endothelial cell proteins, particularly transporters and tight junction proteins. The BBB continues to develop postnatally, adapting its selective barrier function across different developmental phases, and alters with aging and disease. Here we present a global proteomics analysis focused on the ontogeny and aging of proteins in human brain microvessels (BMVs), predominantly composed of brain endothelial cells. Our proteomic profiling quantified 6,223 proteins and revealed possible age-related alteration in BBB permeability due to basement membrane component changes through the early developmental stage and age-dependent changes in transporter expression. Notable changes in expression levels were observed with development and age in nutrient transporters and transporters that play critical roles in drug disposition. This research 1) provides important information on the mechanisms that drive changes in the metabolic content of the brain with age and 2) enables the creation of physiologically based pharmacokinetic models for CNS drug distribution across different life stages.

The Acute Impact of Propofol on Blood-Brain Barrier Integrity in Mice

PURPOSE

We investigated whether short term infusion of propofol, a highly lipophilic agonist at GABAA receptors, which is in widespread clinical use as anesthetic and sedative, affects passive blood-brain barrier (BBB) permeability in vivo.

METHODS

Mice were anesthetized with an intraperitoneal injection of ketamine/xylazine followed by a continuous IV infusion of propofol in lipid emulsion through a tail vein catheter. Control groups received ketamine/xylazine anesthesia and an infusion of Intralipid, or ketamine/xylazine anesthesia only. [13C12]sucrose as a permeability marker was injected as IV bolus 15 min after start of the infusions. Brain uptake clearance, Kin, of sucrose was calculated from the brain concentrations at 30 min and the area under the plasma-concentration time curve. We also measured the plasma and brain concentration of propofol at the terminal time point.

RESULTS

The Kin value for propofol-infused mice was significantly higher, by a factor of 1.55 and 1.87, compared to the Intralipid infusion and the ketamine/xylazine groups, respectively, while the control groups were not significantly different. No difference was seen in the expression levels of tight junction proteins in brain across all groups. The propofol plasma concentration at the end of infusion (10.7 µM) matched the clinically relevant range of blood concentrations reported in humans, while concentration in brain was 2.5-fold higher than plasma.

CONCLUSIONS

Propofol at clinical plasma concentrations acutely increases BBB permeability, extending our previous results with volatile anesthetics to a lipophilic injectable agent. This prompts further exploration, potentially refining clinical practices and ensuring safety, especially during extended propofol infusion schemes.

Antibacterial and Cytotoxicity of Extracts and Isolated Compounds from Artemisia abyssinica: A Combined Experimental and Computational Study

Artemisia abyssinica is a widely cultivated hedge plant in Ethiopia. Traditionally, they have been used to treat a variety of health conditions, including intestinal problems, infectious diseases, tonsillitis, and leishmaniasis. Silica gel chromatographic separation of the methanol and ethyl acetate extracts of the leaves, roots, and stem barks of A. abyssinica led to the isolation of 12 compounds, labeled as 1-12. Among these, compounds 1, 3, 4, 5, and 7-11 are reported as new to the genus Artemisia. The extracts and isolated compounds from A. abyssinica were evaluated for their in vitro antibacterial activity against four bacterial strains: Streptococcus pyogenes, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, using the disc diffusion assay. All of the extracts displayed weak antibacterial activity, with inhibition zone diameters (IZDs) ranging from 6.10 ± 0.3 to 9.30 ± 0.20 mm. The isolated compounds, on the other hand, exhibited weak to moderate antibacterial activity, with IZDs ranging from 6.00 ± 0.300 to 13.50 ± 0.50 mm. The most potent antibacterial activity was observed for compound 6, which showed an IZD of 13.30 ± 0.50 mm against E. coli and 13.50 ± 0.50 mm against P. aeruginosa. This activity was comparable to that of the positive control ceftriaxone, which had IZDs of 14.1 ± 0.3 and 13.8 ± 0.5 mm against E. coli and P. aeruginosa, respectively. The in silico molecular docking analysis against DNA gyrase B revealed that compound 5 showed a higher binding affinity (-6.9 kcal/mol), followed by compound 10 (-6.7 kcal/mol) and compound 12 (-6.3 kcal/mol), whereas ciprofloxacin showed -7.3 kcal/mol. The binding affinities of compounds 5, 11, 10, and 9 were found to be -5.0, -4.3, -4.2, and -4.0 kcal/mol against S. aureus Pyruvate kinase, respectively, whereas ciprofloxacin showed a binding affinity of -4.9 kcal/mol, suggesting that compound 5 had a better binding affinity compared with ciprofloxacin. The effect of extracts of A. abyssinica was evaluated for cytotoxic activity against the breast cancer cell line (MCF-7) by the MTT assay. The extracts induced a decrease in cell viability and exerted a cytotoxic effect at a concentration of 20 μg/mL. The highest percent cell viability was observed for the methanol extract of the stem (92.9%), whereas the least was observed for the methanol extract of the root (34.5%). The result of the latter was significant compared with the positive control. The binding affinities of the isolated compounds were also assessed against human topoisomerase inhibitors IIβ. Results showed that compound 5 showed a binding affinity of -6.0 kcal/mol, followed by 11 (-5.4 kcal/mol), 10 (-5.0 kcal/mol), and 11 (-4.9 kcal/mol). Similar to ciprofloxacin, compounds 4, 5, 6, 9, 10, and 12 comply with Lipinski's rule of five. Overall, the comprehensive investigation of the chemical constituents and their biological activities reinforces the traditional medicinal applications of A. abyssinica and warrants further exploration of this plant as a source of novel therapeutic agents.

Biochanin A restored the blood-brain barrier in cerebral ischemia-reperfusion in rats

OBJECTIVE

Blood-brain barrier is a protective layer that regulates the influx and efflux of biological materials for cerebral tissue. The aim of this study was to investigate the effects of Biochanin A on cerebral histopathology and blood-brain barrier immunohistochemically.

METHODS

A total of 24 rats were assigned to three groups: sham, ischemia-reperfusion, and ischemia-reperfusion+Biochanin A. Ischemia-reperfusion was performed by occluding the left carotid artery for 2/24 h. Notably, 20 mg/kg Biochanin A was administered to rats for 7 days after ischemia-reperfusion. Blood was collected for malondialdehyde and total oxidant/antioxidant status analysis. Cerebral tissues were processed for histopathology and further for immunohistochemical analysis.

RESULTS

Malondialdehyde content with total oxidant status value was significantly increased and total antioxidant status values were significantly decreased in the ischemia-reperfusion group compared with the sham group. Biochanin A treatment significantly improved scores in the ischemia-reperfusion+Biochanin A group. The normal histological appearance was recorded in the cerebral sections of the sham group. Degenerated neurons and vascular structures with disrupted integrity of the cerebral cortex were observed after ischemia-reperfusion. Biochanin A alleviated the histopathology in the cerebrum in the ischemia-reperfusion+Biochanin A group. Ischemia-reperfusion injury decreased the expression of blood-brain barrier in the ischemia-reperfusion group compared to the sham group. Administration of Biochanin A upregulated the blood-brain barrier immunoreactivity in the cerebrum by restoring blood-brain barrier.

CONCLUSION

Cerebral ischemia-reperfusion caused an increase in oxidative stress and pathological lesions in the cerebrum. Biochanin A treatment restored the adverse effects of ischemia-reperfusion injury by restoring blood-brain barrier.

Click3D: Click reaction across deep tissues for whole-organ 3D fluorescence imaging

Click chemistry offers various applications through efficient bioorthogonal reactions. In bioimaging, pretargeting strategies have often been used, using click reactions between molecular probes with a click handle and reporter molecules that make them observable. Recent efforts have integrated tissue-clearing techniques with fluorescent labeling through click chemistry, allowing high-resolution three-dimensional fluorescence imaging. Nevertheless, these techniques have faced a challenge in limited staining depth, confining their use to imaging tissue sections or partial organs. In this study, we introduce Click3D, a method for thoroughly staining whole organs using click chemistry. We identified click reaction conditions that improve staining depth with our custom-developed assay. The Click3D protocol exhibits a greater staining depth compared to conventional methods. Using Click3D, we have successfully achieved whole-kidney imaging of nascent RNA and whole-tumor imaging of hypoxia. We have also accomplished whole-brain imaging of hypoxia by using the clickable hypoxia probe, which has a small size and, therefore, has high permeability to cross the blood-brain barrier.

Stress and the gut-brain axis: an inflammatory perspective

The gut-brain axis (GBA) plays a dominant role in maintaining homeostasis as well as contributes to mental health maintenance. The pathways that underpin the axis expand from macroscopic interactions with the nervous system, to the molecular signals that include microbial metabolites, tight junction protein expression, or cytokines released during inflammation. The dysfunctional GBA has been repeatedly linked to the occurrence of anxiety- and depressive-like behaviors development. The importance of the inflammatory aspects of the altered GBA has recently been highlighted in the literature. Here we summarize current reports on GBA signaling which involves the immune response within the intestinal and blood-brain barrier (BBB). We also emphasize the effect of stress response on altering barriers' permeability, and the therapeutic potential of microbiota restoration by probiotic administration or microbiota transplantation, based on the latest animal studies. Most research performed on various stress models showed an association between anxiety- and depressive-like behaviors, dysbiosis of gut microbiota, and disruption of intestinal permeability with simultaneous changes in BBB integrity. It could be postulated that under stress conditions impaired communication across BBB may therefore represent a significant mechanism allowing the gut microbiota to affect brain functions.

Polyamidoamine Dendrimers: Brain-Targeted Drug Delivery Systems in Glioma Therapy

Glioma is the most common primary intracranial tumor, which is formed by the malignant transformation of glial cells in the brain and spinal cord. It has the characteristics of high incidence, high recurrence rate, high mortality and low cure rate. The treatments for glioma include surgical removal, chemotherapy and radiotherapy. Due to the obstruction of the biological barrier of brain tissue, it is difficult to achieve the desired therapeutic effects. To address the limitations imposed by the brain's natural barriers and enhance the treatment efficacy, researchers have effectively used brain-targeted drug delivery systems (DDSs) in glioma therapy. Polyamidoamine (PAMAM) dendrimers, as branched macromolecular architectures, represent promising candidates for studies in glioma therapy. This review focuses on PAMAM-based DDSs in the treatment of glioma, highlighting their physicochemical characteristics, structural properties as well as an overview of the toxicity and safety profiles.

M1-type microglia-derived exosomes contribute to blood-brain barrier damage

BACKGROUND

As a key substance for intercellular communication, exosomes could be a potential strategy for stroke treatment. Activated microglia disrupt the integrity of blood-brain barrier (BBB) to facilitate the stroke process. Hence, this study was designed to investigate the effect of microglia-derived exosomes on BBB cell model injury and to explore the underlying molecular mechanisms.

METHODS

M1 polarization of BV2 cells was induced with LPS and their derived exosomes were isolated. Astrocytes were cultured in primary culture and constructed with End3 cells as a BBB cell model. After co-culture with exosomes, the BBB cell model was examined for changes in TEER, permeability, and expression of BBB-related proteins (Claudin-1, Occludin, ZO-1 and JAM). Resting and M1-type BV2 cell-derived exosomes perform small RNA sequences and differentially expressed miRNAs (DE-miRNAs) are identified by bioinformatics.

RESULTS

M1-type BV2 cell-derived exosomes decreased End3 cell viability, and increased their apoptotic ratio. Moreover, M1 type BV2 cell-derived exosomes dramatically enhanced the permeability of BBB cell model, and diminished the TEER and BBB-related protein (Claudin-1, Occludin, ZO-1) expression. Notably, resting BV2 cell-derived exosomes had no effect on the integrity of BBB cell model. Sequencing results indicated that 71 DE-miRNAs were present in M1 BV2 cell-derived exosomes, and their targets mediated neurological development and signaling pathways such as MAPK and cAMP. RT-qPCR confirmed the differential expression of mmu-miR-125a-5p, mmu-miR-122b-3p, mmu-miR-139-3p, mmu-miR-330-3p, mmu-miR-3057-5p and mmu-miR-342-3p consistent with the small RNA sequence. Furthermore, Creb1, Jun, Mtor, Frk, Pabpc1 and Sdc1 are the most well-connected proteins in the PPI network.

CONCLUSION

M1-type microglia-derived exosomes contribute to the injury of BBB cell model, which has the involvement of miRNAs. Our findings provide new perspectives and potential mechanisms for future M1 microglia-derived exosomes as therapeutic targets in stroke.

3D Brain Vascular Niche Model Captures Invasive Behavior and Gene Signatures of Glioblastoma

Glioblastoma (GBM) is a lethal brain cancer with no effective treatment; understanding how GBM cells respond to tumor microenvironment remains challenging as conventional cell cultures lack proper cytoarchitecture while in vivo animal models present complexity all at once. Developing a culture system to bridge the gap is thus crucial. Here, we employed a multicellular approach using human glia and vascular cells to optimize a 3-dimensional (3D) brain vascular niche model that enabled not only long-term culture of patient derived GBM cells but also recapitulation of key features of GBM heterogeneity, in particular invasion behavior and vascular association. Comparative transcriptomics of identical patient derived GBM cells in 3D and in vivo xenotransplants models revealed that glia-vascular contact induced genes concerning neural/glia development, synaptic regulation, as well as immune suppression. This gene signature displayed region specific enrichment in the leading edge and microvascular proliferation zones in human GBM and predicted poor prognosis. Gene variance analysis also uncovered histone demethylation and xylosyltransferase activity as main themes for gene adaption of GBM cells in vivo . Furthermore, our 3D model also demonstrated the capacity to provide a quiescence and a protective niche against chemotherapy. In summary, an advanced 3D brain vascular model can bridge the gap between 2D cultures and in vivo models in capturing key features of GBM heterogeneity and unveil previously unrecognized influence of glia-vascular contact for transcriptional adaption in GBM cells featuring neural/synaptic interaction and immunosuppression.

Beneficial Effects of Manilkara zapota-Derived Bioactive Compounds in the Epigenetic Program of Neurodevelopment

Gestational diet has a long-dated effect not only on the disease risk in offspring but also on the occurrence of future neurological diseases. During ontogeny, changes in the epigenetic state that shape morphological and functional differentiation of several brain areas can affect embryonic fetal development. Many epigenetic mechanisms such as DNA methylation and hydroxymethylation, histone modifications, chromatin remodeling, and non-coding RNAs control brain gene expression, both in the course of neurodevelopment and in adult brain cognitive functions. Epigenetic alterations have been linked to neuro-evolutionary disorders with intellectual disability, plasticity, and memory and synaptic learning disorders. Epigenetic processes act specifically, affecting different regions based on the accessibility of chromatin and cell-specific states, facilitating the establishment of lost balance. Recent insights have underscored the interplay between epigenetic enzymes active during embryonic development and the presence of bioactive compounds, such as vitamins and polyphenols. The fruit of Manilkara zapota contains a rich array of these bioactive compounds, which are renowned for their beneficial properties for health. In this review, we delve into the action of each bioactive micronutrient found in Manilkara zapota, elucidating their roles in those epigenetic mechanisms crucial for neuronal development and programming. Through a comprehensive understanding of these interactions, we aim to shed light on potential avenues for harnessing dietary interventions to promote optimal neurodevelopment and mitigate the risk of neurological disorders.

"Filler-Associated Acute Stroke Syndrome": Classification, Predictive Modelling of Hyaluronidase Efficacy, and Updated Case Review on Neurological and Visual Complications

INTRODUCTION

The rising use of soft tissue fillers for aesthetic procedures has seen an increase in complications, including vascular occlusions and neurological symptoms that resemble stroke. This study synthesizes information on central nervous system (CNS) complications post-filler injections and evaluates the effectiveness of hyaluronidase (HYAL) treatment.

METHODS

A thorough search of multiple databases, including PubMed, EMBASE, Scopus, Web of Science, Google Scholar, and Cochrane, focused on publications from January 2014 to January 2024. Criteria for inclusion covered reviews and case reports that documented CNS complications related to soft tissue fillers. Advanced statistical and computational techniques, including logistic regression, machine learning, and Bayesian analysis, were utilized to dissect the factors influencing therapeutic outcomes.

RESULTS

The analysis integrated findings from 20 reviews and systematic analyses, with 379 cases reported since 2018. Hyaluronic acid (HA) was the most commonly used filler, particularly in nasal region injections. The average age of patients was 38, with a notable increase in case reports in 2020. Initial presentation data revealed that 60.9% of patients experienced no light perception, while ptosis and ophthalmoplegia were present in 54.3 and 42.7% of cases, respectively. The statistical and machine learning analyses did not establish a significant linkage between the HYAL dosage and patient recovery; however, the injection site emerged as a critical determinant.

CONCLUSION

The study concludes that HYAL treatment, while vital for managing complications, varies in effectiveness based on the injection site and the timing of administration. The non-Newtonian characteristics of HA fillers may also affect the incidence of complications. The findings advocate for tailored treatment strategies incorporating individual patient variables, emphasizing prompt and precise intervention to mitigate the adverse effects of soft tissue fillers.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Unraveling neurovascular mysteries: the role of endothelial glycocalyx dysfunction in Alzheimer's disease pathogenesis

While cardiovascular disease, cancer, and human immunodeficiency virus (HIV) mortality rates have decreased over the past 20 years, Alzheimer's Disease (AD) deaths have risen by 145% since 2010. Despite significant research efforts, effective AD treatments remain elusive due to a poorly defined etiology and difficulty in targeting events that occur too downstream of disease onset. In hopes of elucidating alternative treatment pathways, now, AD is commonly being more broadly defined not only as a neurological disorder but also as a progression of a variety of cerebrovascular pathologies highlighted by the breakdown of the blood-brain barrier. The endothelial glycocalyx (GCX), which is an essential regulator of vascular physiology, plays a crucial role in the function of the neurovascular system, acting as an essential vascular mechanotransducer to facilitate ultimate blood-brain homeostasis. Shedding of the cerebrovascular GCX could be an early indication of neurovascular dysfunction and may subsequently progress neurodegenerative diseases like AD. Recent advances in in vitro modeling, gene/protein silencing, and imaging techniques offer new avenues of scrutinizing the GCX's effects on AD-related neurovascular pathology. Initial studies indicate GCX degradation in AD and other neurodegenerative diseases and have begun to demonstrate a possible link to GCX loss and cerebrovascular dysfunction. This review will scrutinize the GCX's contribution to known vascular etiologies of AD and propose future work aimed at continuing to uncover the relationship between GCX dysfunction and eventual AD-associated neurological deterioration.

Systemic Effects of Photoactivated 5,10,15,20-tetrakis(N-methylpyridinium-3-yl) Porphyrin on Healthy Drosophila melanogaster

Porphyrins are frequently employed in photodynamic therapy (PDT), a non-invasive technique primarily utilized to treat subcutaneous cancers, as photosensitizing agents (PAs). The development of a new PA with improved tissue selectivity and efficacy is crucial for expanding the application of PDT for the management of diverse cancers. We investigated the systemic effects of 5,10,15,20-tetrakis(N-methylpyridinium-3-yl)-porphyrin (TMPyP3) using Drosophila melanogaster adult males. We established the oral administration schedule and demonstrated that TMPyP3 was absorbed and stored higher in neuronal than in non-neuronal extracts. Twenty-four hours after oral TMPyP3 photoactivation, the quantity of hydrogen peroxide (H2O2) increased, but exclusively in the head extracts. Regardless of photoactivation, TMPyP3 resulted in a reduced concentration of H2O2 after 7 days, and this was linked with a decreased capacity to climb, as indicated by negative geotaxis. The findings imply that systemic TMPyP3 therapy may disrupt redox regulation, impairing cellular signaling and behavioral outcomes in the process. To determine the disruptive effect of porphyrins on redox homeostasis, its duration, and the mechanistic variations in retention across various tissues, more research is required.

The emerging role of brain neuroinflammatory responses in Alzheimer's disease

As the most common cause of dementia, Alzheimer's disease (AD) is characterized by neurodegeneration and synaptic loss with an increasing prevalence in the elderly. Increased inflammatory responses triggers brain cells to produce pro-inflammatory cytokines and accelerates the Aβ accumulation, tau protein hyper-phosphorylation leading to neurodegeneration. Therefore, in this paper, we discuss the current understanding of how inflammation affects brain activity to induce AD pathology, the inflammatory biomarkers and possible therapies that combat inflammation for AD.

Systems-level computational modeling in ischemic stroke: from cells to patients

Ischemic stroke, a significant threat to human life and health, refers to a class of conditions where brain tissue damage is induced following decreased cerebral blood flow. The incidence of ischemic stroke has been steadily increasing globally, and its disease mechanisms are highly complex and involve a multitude of biological mechanisms at various scales from genes all the way to the human body system that can affect the stroke onset, progression, treatment, and prognosis. To complement conventional experimental research methods, computational systems biology modeling can integrate and describe the pathogenic mechanisms of ischemic stroke across multiple biological scales and help identify emergent modulatory principles that drive disease progression and recovery. In addition, by running virtual experiments and trials in computers, these models can efficiently predict and evaluate outcomes of different treatment methods and thereby assist clinical decision-making. In this review, we summarize the current research and application of systems-level computational modeling in the field of ischemic stroke from the multiscale mechanism-based, physics-based and omics-based perspectives and discuss how modeling-driven research frameworks can deliver insights for future stroke research and drug development.

Peptide-Hitchhiking for the Development of Nanosystems in Glioblastoma

Glioblastoma (GBM) remains the epitome of aggressiveness and lethality in the spectrum of brain tumors, primarily due to the blood-brain barrier (BBB) that hinders effective treatment delivery, tumor heterogeneity, and the presence of treatment-resistant stem cells that contribute to tumor recurrence. Nanoparticles (NPs) have been used to overcome these obstacles by attaching targeting ligands to enhance therapeutic efficacy. Among these ligands, peptides stand out due to their ease of synthesis and high selectivity. This article aims to review single and multiligand strategies critically. In addition, it highlights other strategies that integrate the effects of external stimuli, biomimetic approaches, and chemical approaches as nanocatalytic medicine, revealing their significant potential in treating GBM with peptide-functionalized NPs. Alternative routes of parenteral administration, specifically nose-to-brain delivery and local treatment within the resected tumor cavity, are also discussed. Finally, an overview of the significant obstacles and potential strategies to overcome them are discussed to provide a perspective on this promising field of GBM therapy.

Unveiling the impact of aging on BBB and Alzheimer's disease: Factors and therapeutic implications

Alzheimer's disease (AD) is a highly prevalent neurodegenerative condition that has devastating effects on individuals, often resulting in dementia. AD is primarily defined by the presence of extracellular plaques containing insoluble β-amyloid peptide (Aβ) and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau). In addition, individuals afflicted by these age-related illnesses experience a diminished state of health, which places significant financial strain on their loved ones. Several risk factors play a significant role in the development of AD. These factors include genetics, diet, smoking, certain diseases (such as cerebrovascular diseases, obesity, hypertension, and dyslipidemia), age, and alcohol consumption. Age-related factors are key contributors to the development of vascular-based neurodegenerative diseases such as AD. In general, the process of aging can lead to changes in the immune system's responses and can also initiate inflammation in the brain. The chronic inflammation and the inflammatory mediators found in the brain play a crucial role in the dysfunction of the blood-brain barrier (BBB). Furthermore, maintaining BBB integrity is of utmost importance in preventing a wide range of neurological disorders. Therefore, in this review, we discussed the role of age and its related factors in the breakdown of the blood-brain barrier and the development of AD. We also discussed the importance of different compounds, such as those with anti-aging properties, and other compounds that can help maintain the integrity of the blood-brain barrier in the prevention of AD. This review builds a strong correlation between age-related factors, degradation of the BBB, and its impact on AD.