Blood-brain Barrier Disruption Research Articles

Edaravone dexborneol protects against cerebral ischemia/reperfusion-induced blood-brain barrier damage by inhibiting ferroptosis via activation of nrf-2/HO-1/GPX4 signaling

PurposeFerroptosis has recently been recognized as a mechanism of cerebral ischemia-reperfusion (I/R) injury, attributed to blood-brain barrier (BBB) disruption. Edaravone dexboneol (Eda.B) is a novel neuroprotective agent widely employed in ischemic stroke, which is composed of edaravone (Eda) and dexborneol. This study aimed to investigate the protective effects of Eda.B on the BBB in cerebral I/R and explore its potential mechanisms. MethodsTransient middle cerebral artery occlusion (tMCAO) Sprague-Dawley-rats model was used. Rats were randomly assigned to sham-operated group (sham, n = 20), model group (tMCAO, n = 20), Eda.B group (Eda.B, n = 20), Eda group (Eda, n = 20) and dexborneol group (dexborneol, n = 20), and Eda.B + Zinc protoporphyria group (Eda.B + ZnPP, n = 5). Infarct area, cellular apoptosis and neurofunctional recovery were accessed through TTC staining, TUNEL staining, and modified Garcia scoring system, respectively. BBB integrity was evaluated via Evans blue staining. Nuclear factor E2 related factor 2 (Nrf-2)/heme oxygenase 1 (HO-1)/glutathione peroxidase 4 (GPX4) signaling were qualified by Western blot. Transmission electron microscopy (TEM) revealed alterations in ipsilateral brain tissue among groups. Glutathione (GSH) and malondialdehyde (MDA) levels, and Fe2+ tissue content determination were detected. ResultsEda.B effectively improved neurological deficits, diminished infarct area and cellular apoptosis, as well as ameliorated BBB integrity in tMCAO rats. Further, Eda.B significantly inhibited ferroptosis, as evidenced by ameliorated pathological features of mitochondria, down-regulated of MDA and Fe2+ levels and up-regulated GSH content. Mechanistically, Eda.B attenuated BBB disruption via Nrf-2-mediated ferroptosis, promoting nuclear translocation of Nrf-2, increasing HO-1, GPX4 expression, alleviating the loss of zonula occludens 1 (ZO-1) and occludin as well as decreasing 4-hydroxynonenal (4-HNE) level. ConclusionsThis study revealed for the first time that Eda.B safeguarded the BBB from cerebral I/R injury by inhibiting ferroptosis through the activation of the Nrf-2/HO-1/GPX4 axis, providing a novel insight into the neuroprotective effect of Eda.B in cerebral I/R.

Post-endovascular treatment, blood-brain barrier disruption, predicts patient outcomes better than pre-treatment status.

Blood-brain barrier (BBB) disruption is an important pathological change after cerebral infarction that exacerbates brain injury. We aimed to investigate and compare the predictive utility of pre-treatment BBB permeability (BBBP) and BBBP within 1 h after endovascular treatment (EVT) for hemorrhagic transformation (HT) and 90-day prognosis. Patients underwent preoperative computed tomography perfusion (CTP) and non-contrast CT (NCCT) within 1 h after EVT. Preoperative BBBP was determined by the relative permeability surface area product (rPS) in the hypoperfusion area. Postoperative BBBP was determined by the post-EVT Alberta Stroke Program Early CT Score (Post-ASPECTS), which is based on brain parenchymal hyperdensity on the postoperative NCCT. We included 100 patients. Univariate logistic regression analysis revealed correlations of preoperative rPS with HT, poor outcomes, and death. However, these correlations were not observed in multivariate logistic regression. A Post-ASPECTS ≤7 and could independently predict poor outcomes, while Post-ASPECTS ≤6 could independently predict death and HT. The baseline National Institutes of Health Stroke Scale (NIHSS) score could independently predict poor outcomes and death but not HT. A combined model using the baseline NIHSS and Post-ASPECTS scores had better predictive performance for poor outcomes and death than baseline NIHSS score alone; however, it was not superior to the predictive performance of the Post-ASPECTS score. The preoperative rPS cannot independently predict clinical outcomes in EVT-treated patients; contrastingly, the Post-ASPECTS score could independently predict poor outcomes, death, and HT. This parameter could inform prompt postoperative treatment decisions.

Abstract 7163: Pharmacokinetics assessment of intranasal NEO100 treatment on blood-brain barrier disruption and brain penetration of drugs in rodent brain

Abstract Background: Insufficient drug concentrations reaching the brain-localized tumor tissue remains one of the major challenges in the treatment of glioblastoma (GBM). An intranasal (IN) formulation of NEO100 (NeOnc Technologies, Inc., Los Angeles), a highly purified version of perillyl alcohol, has been recently reported to enhance drug concentrations in the brain upon IN co-delivery. Here, we report detailed pharmacokinetics (PK) and tissue analysis to quantitatively examine the extent of increase in drug concentrations in the brain after IN NEO100 administration. Furthermore, we also confirmed that IN NEO100 increases brain drug concentration by circumventing the blood brain barrier. Method: For PK analysis, either IN or oral formulation of a three-drug cocktail (ZEI, consisting of ZN-c3, everolimus, and infigratinib) was used to evaluate the impact of 3% IN NEO100 on the brain penetration profile of the three individual drugs. Athymic mice were grouped into four cohorts to receive 1) oral ZEI; 2) IN ZEI; 3) oral ZEI with IN NEO100; and 4) IN ZEI with IN NEO100. At 2, 4 and 6 hours post ZEI dosing, drug levels in plasma and brain tissue were measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). For BBB disruption study, athymic mice were treated with IN delivery of saline (negative control) or 3% NEO100 one hour post intravenous Evans blue (2%) administration. Tumor bearing mice with disrupted BBB served as positive control. Two hours post Evans blue administration, animals were perfused, and brains were collected and sectioned for confocal microscopy to image Evan’s blue autofluorescence. Results: PK analysis revealed that brain-to-plasma ratios (Kp) for ZN-c3, everolimus, and infigratinib remained nearly equal, independent of the route of administration, i.e. 0.11, 0.03, and 0.82 vs 0.09, 0.03, and 0.87, for IN vs oral routes, respectively. Administration of the ZEI together with IN NEO100, either through oral or IN routes, resulted in higher drug concentrations, both in the plasma and in the brain. However, while overall drug exposure was increased, Kp values of the drugs were not changed. Confocal imaging of brains from mice treated with 3% IN NEO100 did not show presence of Evans blue autofluorescence while positive control mice with disrupted BBB within the tumor core displayed high Evans blue fluorescence. Conclusions: Co-administration of IN NEO100 with ZN-c3, everolimus, and infigratinib increases their brain and plasma exposure. As a result, no significant increase in brain-to-plasma partition was registered for any of the three drugs tested in this study. IN NEO100-mediated increase in brain drug concentration was independent of BBB disruption Citation Format: Anil Thaghalli Shivanna, Tigran Margaryan, Mariya Stavnichuk, William Knight, Sonam Patel, Elaine Cabrales, An-Chi Tien, Thomas Chen, Nader Sanai, Artak Tovmasyan, Shwetal Mehta. Pharmacokinetics assessment of intranasal NEO100 treatment on blood-brain barrier disruption and brain penetration of drugs in rodent brain [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7163.

FGF17 protects cerebral ischemia reperfusion-induced blood-brain barrier disruption via FGF receptor 3-mediated PI3K/AKT signaling pathway

Maintaining blood-brain barrier (BBB) integrity is critical components of therapeutic approach for ischemic stroke. Fibroblast growth factor 17 (FGF17), a member of FGF8 superfamily, exhibits the strongest expression throughout the wall of all major arteries during development. However, its molecular action and potential protective role on brain endothelial cells after stroke remains unclear. Here, we observed reduced levels of FGF17 in the serum of patients with ischemic stroke, as well as in the brains of mice subjected to middle cerebral artery occlusion (MCAO) injury and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced brain microvascular endothelial cells (bEnd.3) cells. Moreover, treatment with exogenous recombinant human FGF17 (rhFGF17) decreased infarct volume, improved neurological deficits, reduced Evans Blue leakage and upregulated the expression of tight junctions in MCAO-injured mice. Meanwhile, rhFGF17 increased cell viability, enhanced trans-endothelial electrical resistance, reduced sodium fluorescein leakage, and alleviated reactive oxygen species (ROS) generation in OGD/R-induced bEnd.3 cells. Mechanistically, the treatment with rhFGF17 resulted in nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and upregulation of heme oxygenase-1 (HO-1) expression. Additionally, based on in-vivo and in-vitro research, rhFGF17 exerted protective effects against ischemia/reperfusion (I/R) -induced BBB disruption and endothelial cell apoptosis through the activation of the FGF receptor 3/PI3K/AKT signaling pathway. Overall, our findings indicated that FGF17 may hold promise as a novel therapeutic strategy for ischemic stroke patients.

Ginsenoside Rd enhances blood-brain barrier integrity after cerebral ischemia/reperfusion by alleviating endothelial cells ferroptosis via activation of NRG1/ErbB4-mediated PI3K/Akt/mTOR signaling pathway

The incidence of ischemic stroke is increasing year by year and showing a younger trend. Impaired blood-brain barrier (BBB) is one of the pathological manifestations caused by cerebral ischemia, leading to poor prognosis of patients. Accumulating evidence indicates that ferroptosis is involved in cerebral ischemia/reperfusion injury (CIRI). We have previously demonstrated that Ginsenoside Rd (G-Rd) protects against CIRI-induced neuronal injury. However, whether G-Rd can attenuate CIRI-induced disruption of the BBB remains unclear. In this study, we found that G-Rd could upregulate the levels of ZO-1, occludin, and claudin-5 in ipsilateral cerebral microvessels and bEnd.3 cells, reduce endothelial cells (ECs) loss and Evans blue (EB) leakage, and ultimately improve BBB integrity after CIRI. Interestingly, the expressions of ACSL4 and COX2 were upregulated, the expressions of GPX4 and xCT were downregulated, the levels of GSH was decreased, and the levels of MDA and Fe2+ were increased in ischemic tissues and bEnd.3 cells after CIRI, suggesting that ECs ferroptosis occurred after CIRI. However, G-Rd can alleviate CIRI-induced BBB disruption by inhibiting ECs ferroptosis. Mechanistically, G-Rd prevented tight junction loss and BBB leakage by upregulating NRG1, activating its tyrosine kinase ErbB4 receptor, and then activating downstream PI3K/Akt/mTOR signaling, thereby inhibiting CIRI-induced ferroptosis in ECs. Taken together, these data provides data support for G-Rd as a promising therapeutic drug for cerebral ischemia.

Hypochlorous acid derived from microglial myeloperoxidase could mediate high-mobility group box 1 release from neurons to amplify brain damage in cerebral ischemia–reperfusion injury

Myeloperoxidase (MPO) plays critical role in the pathology of cerebral ischemia–reperfusion (I/R) injury via producing hypochlorous acid (HOCl) and inducing oxidative modification of proteins. High-mobility group box 1 (HMGB1) oxidation, particularly disulfide HMGB1 formation, facilitates the secretion and release of HMGB1 and activates neuroinflammation, aggravating cerebral I/R injury. However, the cellular sources of MPO/HOCl in ischemic brain injury are unclear yet. Whether HOCl could promote HMGB1 secretion and release remains unknown. In the present study, we investigated the roles of microglia-derived MPO/HOCl in mediating HMGB1 translocation and secretion, and aggravating the brain damage and blood-brain barrier (BBB) disruption in cerebral I/R injury. In vitro, under the co-culture conditions with microglia BV cells but not the single culture conditions, oxygen–glucose deprivation/reoxygenation (OGD/R) significantly increased MPO/HOCl expression in PC12 cells. After the cells were exposed to OGD/R, MPO-containing exosomes derived from BV2 cells were released and transferred to PC12 cells, increasing MPO/HOCl in the PC12 cells. The HOCl promoted disulfide HMGB1 translocation and secretion and aggravated OGD/R-induced apoptosis. In vivo, SD rats were subjected to 2 h of middle cerebral artery occlusion (MCAO) plus different periods of reperfusion. Increased MPO/HOCl production was observed at the reperfusion stage, accomplished with enlarged infarct volume, aggravated BBB disruption and neurological dysfunctions. Treatment of MPO inhibitor 4-aminobenzoic acid hydrazide (4-ABAH) and HOCl scavenger taurine reversed those changes. HOCl was colocalized with cytoplasm transferred HMGB1, which was blocked by taurine in rat I/R-injured brain. We finally performed a clinical investigation and found that plasma HOCl concentration was positively correlated with infarct volume and neurological deficit scores in ischemic stroke patients. Taken together, we conclude that ischemia/hypoxia could activate microglia to release MPO-containing exosomes that transfer MPO to adjacent cells for HOCl production; Subsequently, the production of HOCl could mediate the translocation and secretion of disulfide HMGB1 that aggravates cerebral I/R injury. Furthermore, plasma HOCl level could be a novel biomarker for indexing brain damage in ischemic stroke patients.

Changes of rat’s brain vesseles after air shock wave exposure

Mild blast-induced traumatic brain injury is common among the military, resulting in cognitive impairment, reduced socialization, which leads to disability and, as a result, a deterioration in the quality of life. It is considered that blood-brain barrier disruption and microvascular dysfunction are the key to this type of injury. The purpose of study was to study changes in brain vessels after air shock wave exposure. The study was carried out on 48 mature male Wistar rats, which were randomly divided into 2 groups: an experimental group, in which animals were subjected to inhalation anesthesia using halothane and exposed to a shock wave with an overpressure of 26.4±3.6 kPa, and a Sham group. After simulation of injury on days 1st, 3rd, 7th, 14th, and 21st, the rats were euthanized and the brain was removed and after all subjected to standard histological procedures and stained with hematoxylin and eosin. For immunohistochemical studies, as primary antibodies were used eNOS. The finished preparations were examined by light microscopy and photographed. Disorders of the cerebral vessels in experimental rats were detected from day 1st of the posttraumatic period. It was found that the blast wave led to vascular rupture, as well as increased vascular permeability with diapedesis of red blood cells and cerebral edema for up to 21st days. Focal violations of the vascular wall integrity in cortical and hippocampal hemocapillaries, venular link of the submembrane vessels; changes in the morphology of the metabolic vessels endothelium; uneven blood filling of the brain vessels were of major importance. These changes indicate that increased eNOS expression leads to dilation of cerebral vessels, which is a compensatory mechanism in response to injury to improve cerebral blood circulation. However, eNOS is not involved in vasodilation, which we observed up to 21st day post-trauma.

TIMP1 protects against blood-brain barrier disruption after subarachnoid haemorrhage by inhibiting ubiquitination of astrocytic β1-integrin

BackgroundAstrocytes regulate blood-brain barrier (BBB) integrity, whereas subarachnoid haemorrhage (SAH) results in astrocyte dysregulation and BBB disruption. Here, we explored the involvement of tissue inhibitor of matrix metalloprotease-1 (TIMP1) in...

Association between renal insufficiency and lesion characteristics of posterior reversible encephalopathy syndrome.

Posterior reversible encephalopathy syndrome (PRES) is characterized by cerebral blood flow dysregulation and the blood-brain barrier (BBB) disruption. While renal insufficiency has been considered a factor in BBB fragility, the relationship between renal insufficiency and the PRES lesions volume remains unclear. This observational study was performed retrospectively. PRES patients were categorized into two groups with renal insufficiency, defined as an estimated glomerular filtration rate (eGFR) of less than 60mL/min/1.73m2 on the day of symptom occurrence. Lesion volume was measured using fluid-attenuated inversion recovery (FLAIR) imaging, and the brain was divided into nine regions. The volume of the parietal-occipital-temporal lobe was considered typical, while the other six regions were labeled as atypical. The study included 200 patients, of whom 94 (47%) had renal insufficiency. Patients with renal insufficiency had a larger lesion volume (144.7 ± 125.2cc) compared to those without renal insufficiency (110.5 ± 93.2cc; p = 0.032); particularly in the atypical lesions volume (49.2 ± 65.0 vs. 29.2 ± 44.3cc; p = 0.013). However, there was no difference in the reversibility of the lesions (35.2 ± 67.5 vs. 18.8 ± 33.4cc; p = 0.129). Multiple regression analysis revealed that decreases in eGFR (β = -0.34, 95% CI -0.62-0.05, p = 0.020) were positively associated with total lesion volume. Our findings suggest that PRES patients with renal insufficiency experience more severe lesion volumes, likely due to the atypical brain regions involvement. The lesions involving atypical regions may have a similar pathophysiology to typical lesions, as the PRES lesions reversibility was found to be similar between individuals with and without renal insufficiency.

Lipopolysaccharide exacerbates depressive-like behaviors in obese rats through complement C1q-mediated synaptic elimination by microglia.

Prolonged high-fat diet (HFD) consumption has been shown to impair cognition and depression. The combined effects of HFD and lipopolysaccharide (LPS) administration on those outcomes have never been thoroughly investigated. This study investigated the effects of LPS, HFD consumption, and a combination of both conditions on microglial dysfunction, microglial morphological alterations, synaptic loss, cognitive dysfunction, and depressive-like behaviors. Sixty-four male Wistar rats were fed either a normal diet (ND) or HFD for 12 weeks, followed by single dose-subcutaneous injection of either vehicle or LPS. Then, cognitive function and depressive-like behaviors were assessed. Then, rats were euthanized, and the whole brain, hippocampus, and spleen were collected for further investigation, including western blot analysis, qRT-PCR, immunofluorescence staining, and brain metabolome determination. HFD-fed rats developed obese characteristics. Both HFD-fed rats with vehicle and ND-fed rats with LPS increased cholesterol and serum LPS levels, which were exacerbated in HFD-fed rats with LPS. HFD consumption, but not LPS injection, caused oxidative stress, blood-brain barrier disruption, and decreased neurogenesis. Both HFD and LPS administration triggered an increase in inflammatory genes on microglia and astrocytes, increased c1q colocalization with microglia, and increased dendritic spine loss, which were exacerbated in the combined conditions. Both HFD and LPS altered neurotransmitters and disrupted brain metabolism. Interestingly, HFD consumption, but not LPS, induced cognitive decline, whereas both conditions individually induced depressive-like behaviors, which were exacerbated in the combined conditions. Our findings suggest that LPS aggravates metabolic disturbances, neuroinflammation, microglial synaptic engulfment, and depressive-like behaviors in obese rats.

Exacerbation of thromboinflammation by JAK2V617F mutation worsens the prognosis of cerebral venous sinus thrombosis

AbstractCerebral venous sinus thrombosis (CVST) is an uncommon venous thromboembolic event accounting for <1% of strokes resulting in brain parenchymal injuries. JAK2V617F mutation, the most frequent driving mutation of myeloproliferative neoplasms, has been reported to be associated with worse clinical outcomes in patients with CVST. We investigated whether hematopoietic JAK2V617F expression predisposes to specific pathophysiological processes and/or worse prognosis after CVST. Using an in vivo mouse model of CVST, we analyzed clinical, biological, and imaging outcomes in mice with hematopoietic-restricted Jak2V617F expression, compared with wild-type Jak2 mice. In parallel, we studied a human cohort of JAK2V617F-positive or -negative CVST. Early after CVST, mice with hematopoietic Jak2V617F expression had increased adhesion of platelets and neutrophils in cerebral veins located in the vicinity of CVST. On day 1, Jak2V617F mice had a worse outcome characterized by significantly more frequent and severe intracranial hemorrhages (ICHs) and higher mortality rates. Peripheral neutrophil activation was enhanced, as indicated by higher circulating platelet–neutrophil aggregates, upregulated CD11b expression, and higher myeloperoxydase plasma level. Concurrently, immunohistological and brain homogenate analysis showed higher neutrophil infiltration and increased blood-brain barrier disruption. Similarly, patients with JAK2V617F-positive CVST tended to present higher thrombotic burden and had significantly higher systemic immune-inflammation index, a systemic thromboinflammatory marker, than patients who were JAK2V617F-negative. In mice with CVST, our study corroborates that Jak2V617F mutation leads to a specific pattern including increased thrombotic burden, ICH, and mortality. The exacerbated thromboinflammatory response, observed both in mice and patients positive for JAK2V617F, could contribute to hemorrhagic complications.

The protective effects of statins in traumatic brain injury.

Traumatic brain injury (TBI), often referred to as the "silent epidemic", is the most common cause of mortality and morbidity worldwide among all trauma-related injuries. It is associated with considerable personal, medical, and economic consequences. Although remarkable advances in therapeutic approaches have been made, current treatments and clinical management for TBI recovery still remain to be improved. One of the factors that may contribute to this gap is that existing therapies target only a single event or pathology. However, brain injury after TBI involves various pathological mechanisms, including inflammation, oxidative stress, blood-brain barrier (BBB) disruption, ionic disturbance, excitotoxicity, mitochondrial dysfunction, neuronal necrosis, and apoptosis. Statins have several beneficial pleiotropic effects (anti-excitotoxicity, anti-inflammatory, anti-oxidant, anti-thrombotic, immunomodulatory activity, endothelial and vasoactive properties) in addition to promoting angiogenesis, neurogenesis, and synaptogenesis in TBI. Supposedly, using agents such as statins that target numerous and diverse pathological mechanisms, may be more effective than a single-target approach in TBI management. The current review was undertaken to investigate and summarize the protective mechanisms of statins against TBI. The limitations of conducted studies and directions for future research on this potential therapeutic application of statins are also discussed.

Cerebral Perfusion Characteristics and Dynamic Brain Structural Changes in Stroke-Prone Renovascular Hypertensive Rats: A Preclinical Model for Cerebral Small Vessel Disease.

Hypertension is a leading cause of cerebral small vessel disease (CSVD) and vascular dementia in elderly individuals. We aimed to assess cerebral perfusion and dynamic changes in brain structure in stroke-prone renovascular hypertensive rats (RHRSPs) with different durations of hypertension and to investigate whether they have pathophysiological features similar to those of humans with CSVD.The RHRSP model was established using the two-kidney, two-clip (2k2c) method, and the Morris water maze (MWM) test, MRI, immunohistochemistry, and biochemical analysis were performed at multiple time points for up to six months following the 2k2c operation.Systolic blood pressure was significantly greater in the RHRSP group than in the sham-operated group at week 4 post-surgery and continued to increase over time, leading to cognitive decline by week 20. Arterial spin labeling revealed cerebral hypoperfusion in the RHRSP group at 8 weeks, accompanied by vascular remodeling and decreased vessel density. Diffusion tensor imaging and Luxol fast blue staining indicated that white matter disintegration and demyelination gradually progressed in the corpus callosum and that myelin basic protein levels decreased. Eight weeks after surgery, blood-brain barrier (BBB) leakage into the corpus callosum was observed. The albumin leakage area was negatively correlated with the myelin sheath area (r=-0.88, p<0.001). RNA-seq analysis revealed downregulation of most angiogenic genes and upregulation of antiangiogenic genes in the corpus callosum of RHRSPs 24 weeks after surgery.RHRSPs developed cerebral hypoperfusion, BBB disruption, spontaneous white matter damage, and cognitive impairment as the duration of hypertension increased. RHRSPs share behavioral and neuropathological characteristics with CSVD patients, making them suitable animal models for preclinical trials related to CSVD.

Endothelial peroxiredoxin-4 is indispensable for blood–brain barrier integrity and long-term functional recovery after ischemic stroke

The endothelial lining of cerebral microvessels is damaged relatively early after cerebral ischemia/reperfusion (I/R) injury and mediates blood-brain barrier (BBB) disruption, neurovascular injury, and long-term neurological deficits. I/R induces BBB leakage within 1 h due to subtle structural alterations in endothelial cells (ECs), including reorganization of the actin cytoskeleton and subcellular redistribution of junctional proteins. Herein, we show that the protein peroxiredoxin-4 (Prx4) is an endogenous protectant against endothelial dysfunction and BBB damage in a murine I/R model. We observed a transient upregulation of Prx4 in brain ECs 6 h after I/R in wild-type (WT) mice, whereas tamoxifen-induced, selective knockout of Prx4 from endothelial cells (eKO) mice dramatically raised vulnerability to I/R. Specifically, eKO mice displayed more BBB damage than WT mice within 1 to 24 h after I/R and worse long-term neurological deficits and focal brain atrophy by 35 d. Conversely, endothelium-targeted transgenic (eTG) mice overexpressing Prx4 were resistant to I/R-induced early BBB damage and had better long-term functional outcomes. As demonstrated in cultures of human brain endothelial cells and in animal models of I/R, Prx4 suppresses actin polymerization and stress fiber formation in brain ECs, at least in part by inhibiting phosphorylation/activation of myosin light chain. The latter cascade prevents redistribution of junctional proteins and BBB leakage under conditions of Prx4 repletion. Prx4 also tempers microvascular inflammation and infiltration of destructive neutrophils and proinflammatory macrophages into the brain parenchyma after I/R. Thus, the evidence supports an indispensable role for endothelial Prx4 in safeguarding the BBB and promoting functional recovery after I/R brain injury.

Human umbilical cord mesenchymal stem cells reverse depression in rats induced by chronic unpredictable mild stress combined with lipopolysaccharide.

Inflammation and oxidative stress are considered crucial to the pathogenesis of depression. Rat models of depression can be created by combined treatments of chronic unpredictable mild stress (CUMS) and lipopolysaccharide (LPS). Behaviors associated with depression could be improved by treatment with mesenchymal stem cells (MSCs) owing to immunomodulatory functions of the cells. Therapeutic potentials of the MSCs to reverse pro-inflammatory cytokines, proteins, and metabolites were identified by transcriptomic, proteomic, and metabolomic analysis, respectively. A depression model was established in male SD rats by 2 weeks of CUMS combined with LPS. The models were verified by behavioral tests, namely SPT, OFT, EPM, and qRT-PCR for pro-inflammatory cytokines. Such depressed rats were administered human umbilical cord MSCs (hUC-MSCs) via the tail vein once a week for 2 and 4 weeks. The homing capacity was confirmed by detection of the fluorescent dye on day 7 after the hUC-MSCs were labeled with CM-Dil and administered. The expression of GFAP in astrocytes serves as a biomarker of CNS disorders and IBA1 in microglia serves as a marker of microglia activation were detected by immunohistochemistry at 2 and 4 weeks after final administration of hUC-MSCs. At the same time, transcriptomics of rat hippocampal tissue, proteomic and metabolomic analysis of the serum from the normal, depressed, and treated rats were also compared. Reliable models of rat depression were successfully induced by treatments of CUMS combined with LPS. Rat depression behaviors, pro-inflammatory cytokines, and morphological disorders of the hippocampus associated with depression were reversed in 4 weeks by hUC-MSC treatment. hUC-MSCs could reach the hippocampus CA1 region through the blood circulation on day 7 after administration owing to the disruption of blood brain barrier (BBB) by microglial activation from depression. Differentiations of whole-genome expression, protein, and metabolite profiles between the normal and depression-modeled rats, which were analyzed by transcriptomic, proteomics, and metabolomics, further verified the high association with depression behaviors. Rat depression can be reversed or recovered by treatment with hUC-MSCs.

Electroacupuncture regulates histone acetylation of Bcl-2 and Caspase-3 genes to improve ischemic stroke injury

BackgroundImbalances between Bcl-2 and caspase-3 are significant evidence of apoptosis, which is considered an influential factor in rapidly occurring neuronal cell death and the decline of neurological function after stroke. Studies have shown that acupuncture can reduce poststroke brain cell damage via either an increase in Bcl-2 or a reduction in caspase-3 exposure. The current study aimed to investigate whether acupuncture could modulate Bcl-2 and caspase-3 expression through histone acetylation modifications, which could potentially serve as a neuroprotective mechanism. MethodsThis study used TTC staining, Nissl staining, Clark neurological system score, and Evans Blue (EB) extravasation to evaluate neurological damage following stroke. The expression of Bcl-2/caspase-3 mRNA was detected by real-time fluorescence quantification of PCR (real-time PCR), whereas the protein expression levels of Bcl-2, Bax, caspase-3, and cleaved caspase-3 were assessed using western blotting. TUNEL staining of the ischemic cortical neurons determined apoptosis in the ischemic cortex. Histone acetyltransferase (HAT) and histone deacetylase (HDAC) activities, along with the protein performance of AceH3, H3K9ace, and H3K27ace, were detected to evaluate the degree of histone acetylation. The acetylation enrichment levels of H3K9 and K3K27 in the Bcl-2/caspase-3 gene were assessed using Chromatin Immunoprecipitation (ChIP) assay. ResultsOur data demonstrated that electroacupuncture (EA) exerts a significant neuroprotective effect in middle cerebral artery occlusion (MCAO) rats, as evidenced by a reduction in infarct volume, neuronal damage, Blood-Brain Barrier (BBB) disruption, and decreased apoptosis of ischemic cortical neurons. EA treatment can promote the mRNA and protein expression of the Bcl-2 gene in the ischemic brain while reducing the mRNA and protein expression levels of caspase-3 and effectively decreasing the protein expression levels of Bax and cleaved caspase-3. More importantly, EA treatment enhanced the level of histone acetylation, including Ace-H3, H3K9ace, and H3K27ace, significantly enhanced the occupancy of H3K9ace/H3K27ace at the Bcl-2 promoter, and reduced the enrichment of H3K9ace and H3K27ace at the caspase-3 promoter. However, the Histone Acetyltransferase inhibitor (HATi) treatment reversed these effects. ConclusionsOur data demonstrated that EA mediated the expression levels of Bcl-2 and caspase-3 in MCAO rats by regulating the occupancy of acetylated H3K9/H3K27 at the promoters of these two genes, thus exerting a cerebral protective effect in ischemic reperfusion (I/R) injury.

Anesthesia-mediated neuroinflammatory sequelae in post operative cognitive dysfunction: mechanisms and therapeutic implications

Post-operative cognitive dysfunction (POCD) is an iatrogenic cognitive decline with unclear etiology. While current hypotheses include surgical and pharmacological-induced neuroinflammatory mechanisms, the growing prevalence, especially amongst the geriatric population, emphasizes the ambiguity of the dysfunction. Recent studies have highlighted the potential role of general and regional anesthesia in the pathogenesis of POCD; these pharmacological effects have been demonstrated to disrupt blood-brain barrier integrity, influence microglial polarization, and have been linked to worsening prognoses in cognitive decline. Moreover, mechanical stress from surgical intervention and reperfusion injury may exacerbate the generation of reactive oxygen species (ROS), thereby increasing oxidative stress to the brain synergistically with blood-brain barrier disruptions. In previous studies, factors for the variable incidence and various risk factors have been explored. In this review, we examine the pharmacological effects of local, regional, and general anesthesia on molecular and cellular glial response, along with its intercellular interactions and previously reported clinical outcomes.

Central Nervous System Antimicrobial Exposure and Proposed Dosing for Anthrax Meningitis.

The high mortality of systemic anthrax is likely a consequence of the severe central nervous system inflammation that occurs in anthrax meningitis. Effective treatment of such infections requires, at a minimum, adequate cerebrospinal fluid (CSF) antimicrobial concentrations. We reviewed English medical literature and regulatory documents to extract information on serum and CSF exposures for antimicrobials with in vitro activity against Bacillus anthracis. Using CSF pharmacokinetic exposures and in vitro B. anthracis susceptibility data, we used population pharmacokinetic modeling and Monte Carlo simulations to determine whether a specific antimicrobial dosage would likely achieve effective CSF antimicrobial activity in patients with normal to inflamed meninges (ie, an intact to markedly disrupted blood-brain barrier). The probability of microbiologic success at achievable antimicrobial dosages was high (≥95%) for ciprofloxacin, levofloxacin (500 mg every 12 hours), meropenem, imipenem/cilastatin, penicillin G, ampicillin, ampicillin/sulbactam, doxycycline, and minocycline; acceptable (90%-95%) for piperacillin/tazobactam and levofloxacin (750 mg every 24 hours); and low (<90%) for vancomycin, amikacin, clindamycin, and linezolid. Prompt empiric antimicrobial therapy of patients with suspected or confirmed anthrax meningitis may reduce the high morbidity and mortality. Our data support using several β-lactam-, fluoroquinolone-, and tetracycline-class antimicrobials as first-line and alternative agents for treatment of patients with anthrax meningitis; all should achieve effective microbiologic exposures. Our data suggest antimicrobials that should not be relied on to treat suspected or documented anthrax meningitis. Furthermore, the protein synthesis inhibitors clindamycin and linezolid can decrease toxin production and may be useful components of combination therapy.

Glypican-1-targeted antibody–drug conjugate inhibits the growth of glypican-1-positive glioblastoma

Glioblastoma is the deadliest form of brain tumor. The presence of the blood–brain barrier (BBB) significantly hinders chemotherapy, necessitating the development of innovative treatment options for this tumor. This report presents the in vitro and in vivo efficacy of an antibody–drug conjugate (ADC) that targets glypican-1 (GPC1) in glioblastoma. The GPC1-ADC was created by conjugating a humanized anti-GPC1 antibody (clone T2) with monomethyl auristatin E (MMAE) via maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl linkers. Immunohistochemical staining analysis of a glioblastoma tissue microarray revealed that GPC1 expression was elevated in more than half of the cases. GPC1-ADC, when bound to GPC1, was efficiently and rapidly internalized in glioblastoma cell lines. It inhibited the growth of GPC1-positive glioma cell lines by inducing cell cycle arrest in the G2/M phase and triggering apoptosis in vitro. We established a heterotopic xenograft model by subcutaneously implanting KALS-1 and administered GPC1-ADC intravenously. GPC1-ADC significantly inhibited tumor growth and increased the number of mitotic cells. We also established an orthotopic xenograft model by intracranially implanting luciferase-transfected KS-1-Luc#19. After injecting Evans blue and resecting brain tissues, dye leakage was observed in the implantation area, confirming BBB disruption. We administered GPC1-ADC intravenously and measured the luciferase activity using an in vivo imaging system. GPC1-ADC significantly inhibited tumor growth and extended survival. In conclusion, GPC1-ADC demonstrated potent intracranial activity against GPC1-positive glioblastoma in an orthotopic xenograft model. These results indicate that GPC1-ADC could represent a groundbreaking new therapy for treating glioblastoma beyond the BBB.

Repeated blood–brain barrier opening with a nine-emitter implantable ultrasound device in combination with carboplatin in recurrent glioblastoma: a phase I/II clinical trial

Here, the results of a phase 1/2 single-arm trial (NCT03744026) assessing the safety and efficacy of blood-brain barrier (BBB) disruption with an implantable ultrasound system in recurrent glioblastoma patients receiving carboplatin are reported. A nine-emitter ultrasound implant was placed at the end of tumor resection replacing the bone flap. After surgery, activation to disrupt the BBB was performed every four weeks either before or after carboplatin infusion. The primary objective of the Phase 1 was to evaluate the safety of escalating numbers of ultrasound emitters using a standard 3 + 3 dose escalation. The primary objective of the Phase 2 was to evaluate the efficacy of BBB opening using magnetic resonance imaging (MRI). The secondary objectives included safety and clinical efficacy. Thirty-three patients received a total of 90 monthly sonications with carboplatin administration and up to nine emitters activated without observed DLT. Grade 3 procedure-related adverse events consisted of pre syncope (n = 3), fatigue (n = 1), wound infection (n = 2), and pain at time of device connection (n = 7). BBB opening endpoint was met with 90% of emitters showing BBB disruption on MRI after sonication. In the 12 patients who received carboplatin just prior to sonication, the progression-free survival was 3.1 months, the 1-year overall survival rate was 58% and median overall survival was 14.0 months from surgery.